The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101MICROLEAKAGE ASSESSMENT AND EFFICIENCY OF TWO ANTIMICROBIAL PIT AND FISSURE SEALANTS: AN IN-VITRO STUDY7117197501910.21608/edj.2017.75019ENInesEl ZayatAssistant Professor, Department of Restorative Dentistry, Faculty of Oral and Dental Medicine, Misr International UniversityMaiEl BannaAssistant Professor, Department of Restorative Dentistry, Faculty of Oral and Dental Medicine, Misr International UniversityDoaa R .AhmedLecturer, Department of Restorative Dentistry, Faculty of Dentistry, Alexandria UniversityAmalEl ZayatFellow Dentist, Institute of Medical Research, Alexandria UniversityJournal Article20200302The purpose of this study was to evaluate microleakage and antimicrobial efficiency of two pit and fissure sealants, SeLECT Defense® and Ultra Seal XT Plus. <br />Methods: Intact human premolars were selected for the microleakage test and assigned randomly to two groups (n=20) according to the sealant used. After sealants application, the specimens were thermocycled then subjected to silver nitrate staining. Thin sections were obtained from each specimen, photo-developed then observed with polarizing light microscope. Microleakage was assessed according to a (0-4) scoring method where 0 indicated no leakage and 4 indicating most leakage to the base of the fissures. For evaluation of antimicrobial efficiency, tooth specimens were obtained from intact human molars and treated with Select Defense sealant (Group A), Ultra Seal XT Plus (Group B), while tooth specimens in Group C were left as control (n=20). Bacterial viability was evaluated after 24h, 48h, 72h and 96h, and was conducted by staining the adherent plaque with live/dead bacterial stain then observed with confocal laser scanning microscopy. Data obtained from microleakage and bacterial viability testes were analyzed using one-way ANOVA, Chi-square tests and Yuen-Welch tests (α=0.05). <br />Results: Microleakage scores were significantly lower with SeLECT Defense compared to Ultra Seal XT Plus (p<0.01). Analysis of bacterial viability data indicated both sealants tested showed significantly lower live/dead ratios means compared to the control group at 24h. The difference was not as significant after 96h of incubation. <br />Conclusion: The results of the current study indicate that both sealants tested show an antimicrobial efficiency that is more marked at 24h, nevertheless SeLECT Defense sealant could have a lower chance of failing due to microleakage compared to Ultra Seal XT Plus sealant.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101BONE RESPONSE TO DIFFERENT IMPLANT ABUTMENT CONNECTIONS IN IMMEDIATELY LOADED PARTIAL OVERDENTURES; A RANDOMIZED SPLIT MOUTH CLINICAL TRIAL7217277502010.21608/edj.2017.75020ENAhmedFahmyLecturer of Prosthodontics, Faculty of Dentistry, Cairo University.KhaledAzizAssociate Professor of Prosthodontics, Faculty of Dentistry, Cairo University.Journal Article20200302Introduction: Management of long span anterior edentulous area is considered a prosthodontics challenge related to many problems as length of the span, as well as functional principles are considered upon diagnosis, in addition to other biomechanical consideration and esthetics. <br />Materials and Methods: This study was carried out to detect the effect of using different implant abutment connections on supporting structure of implants supported partial overdenture in maxillary Kennedy class IV cases with immediate loading. Ten male patients were selected each patient received maxillary two implants, one with platform switch connection and other with conventional platform design. Both implants were immediately loaded with partial overdenture through a pair of locator attachment. Radiographic evaluations for bone height changes around installed implants were carried out at the time of overdenture insertion and after3, 6 and 9 months follow up. <br />Results: A statistically significant difference between the two implant designs was reported for all the follow up periods with Platform switched implant showing less values of bone loss compared to conventional platform implant. <br />Conclusion: The current study concluded that platform switching with immediate loading protocol are capable of reducing the amount of crestal bone loss.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101MARGINAL BONE LOSS OF TWO IMMEDIATELY LOADED NARROW VERSUS STANDARD DIAMETER IMPLANTS RETAINING MANDIBULAR OVERDENTURES: A RANDOMIZED CONTROLLED PILOT STUDY7297387502110.21608/edj.2017.75021ENIman AWRadiAssociate Professor, Prosthodontic Department, Faculty of Oral and Dental Medicine, Cairo University, Egypt.
Member of Evidence Based Dentistry Centre, Faculty of Oral and Dental Medicine, Cairo University, Egypt.Journal Article20200302Purpose: To evaluate peri-implant marginal bone loss in two immediately loaded narrow versus standard diameter implants retaining mandibular implant overdentures. <br />Material and methods: Twenty completely edentulous patients were collected from Outpatient Clinic of Prosthodontic Department, Faculty of Oral and Dental Medicine, Cairo University, for whom maxillary and mandibular dentures were constructed. Patients were randomly divided into two equal groups; N group which 10 received narrow (3x12 mm) and S group, 20 standard diameter implants (3.7x 12mm). Implants were immediately loaded using the previously constructed dentures, ball attachments for retention and silicone based resilient liner acting as female receptacle. Marginal bone loss was then assessed using standardized digital peri-apical radiographs at denture insertion, then 6 and 12 months later. Independent t test was used to study effect of group, while repeated measure ANOVA was used for studying effect of time on peri-implant marginal bone loss. Results were considered significant at p ≤0.05. <br />Results: For both groups a significant difference was found among the different follow up intervals and between mesial and distal aspects of all implants at 0-6 and 0-12 months. N was associated with significantly higher bone loss if compared to S at all follow up intervals with the highest bone loss recorded at distal aspects of both groups after one year (N=1.485±0.215, S=1.062±0.125). <br />Conclusion: Despite of the 100% one year survival rate found in both groups of the study, immediately loaded conventional diameter implants retaining mandibular overdentures are associated with lesser marginal bone loss if compared to immediately loaded narrow diameter ones.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101PREDICTABILITY OF PRIMARY IMPLANT STABILITY FROM CORTICAL BONE THICKNESS AND BONE DENSITY VALUES OF CONE BEAM COMPUTED TOMOGRAPHIC SCANS: A CROSS SECTIONAL STUDY7397467502210.21608/edj.2017.75022ENIman AWRadiAssociate Professor of Prosthodontics, Member of the Evidence Based Committee, Faculty of Oral and Dental
Medicine, Cairo University.NouranAbdel-NabiLecturer of Prosthodontics, Faculty of Oral and Dental Medicine, Cairo University.Journal Article20200302Statement of Problem: Prediction of primary implant stability is important before surgery to determine the possibility of immediate loading. <br />Purpose: To evaluate the predictability of primary implant stability from cortical bone thickness and bone density values of cone bone beam computed tomography (CBCT). <br />Material and Methods: 10 completely and partially edentulous patients were<br /> thickness and bone density, was investigated using Pearson’s correlation and multiple regression analysis. <br />Results: The regression model accounted for 61.5% of the variations in the implant stability with an insignificant impact (p value=014). Age was found to be the only variable that has a significant impact on implant stability with a coefficient correlation of – 0.47 and a p value of 0.03. Conclusions: Within the limitations of this study neither cortical bone thickness nor bone density obtained from a CBCT can predict primary implant stability. On the contrary, age seems to have a significant impact on the primary implant stability. <br />Clinical implications: CBCT does not seem to be a valuable tool for predicting the primary implant stability. Bone density and thickness readings should be interpreted with cautions.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101BIOMECHANICAL BEHAVIOR OF THREE SOLITARY IMPLANTS SUPPORTING MANDIBULAR OVERDENTURE: A RADIOGRAPHIC EVALUATION7477537502310.21608/edj.2017.75023ENKhaledAzizLecturer of Prosthodontics, Faculty of Dentistry, Cairo University.Journal Article20200302Objective: Bone assessment around three implants supporting mandibular overdenture<br />Methodology: Ten completely edentulous patient were meticulously selected to receive a mandibular overdenture retained by three un-splinted implants placed in the anterior region with ball and socket attachments. Mesial and distal bone for the three implants levels were monitored at the time of denture delivery, 6 and 12months.<br />Results: The results of this study revealed insignificant difference between the bone level and percentage of bone loss for the three implants along the whole study period. <br />Conclusion: The three-implant overdenture treatment can achieve favorable results from a biomechanical point of view as well as peri-implant bone responseThe Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101VERTICAL MARGINAL GAP DISTANCE AND RETENTION OF DIFFERENT CAD/CAM CERAMIC ENDOCROWNS WITH TWO PREPARATION DESIGNS7557677612310.21608/edj.2017.76123ENRehamElbastyLecturer of Fixed Prostodontics, Faculty of Oral and Dental Medicine, Cairo UniversityAdelEltannirProfessor of Fixed Prostodontics, Faculty of Oral and Dental Medicine, Cairo UniversityAtefShakerProfessor of Fixed Prostodontics, Faculty of Oral and Dental Medicine, Cairo UniversityJournal Article20200307<strong>Statement of the problem: </strong>The rehabilitation of severely damaged coronal hard tissue and endodontically treated teeth has always been a challenge in reconstructive dentistry. These teeth have been shown to exhibit a significantly shorter service life and an increased failure rate when compared with vital teeth.
<strong>Objective: </strong>This study evaluated the vertical marginal gap distance and retention of bonded CAD/CAM Ceramic Endocrowns as a conservative alternative in endodontically treated molar teeth following thermal cycling and fatigue loading compared to post and core supported Ceramic crowns.
<strong>Methods: </strong>Ninty caries free human molar teeth were selected and mounted in epoxy resin blocks. For vertical marginal gap distance test, sixty teeth were assigned into six groups (n=10) according to type of restoration as follows; GroupI: Endodontically treated teeth incorporating 1mm ferrule restored with IPS Empress CAD endocrowns. Group II: Endodontically treated teeth incorporating 1mm ferrule restored with IPS e.max CAD endocrowns. Group III: Endodontically treated teeth without incorporating ferrule restored with IPS Empress CAD endocrowns. Group IV: Endodontically treated teeth without incorporating ferrule restored with IPS e.max CAD endocrowns. Group V: Endodontically treated teeth incorporating 1mm ferrule restored with glass-fiber posts, composite cores and IPS Empress CAD crowns serving as a control group. Group IV<strong>:</strong>Endodontically treated teeth incorporating 1mm ferrule restored with glass-fiber posts, composite cores and IPS e.max crowns serving as another control group. For retention test, thirty teeth were divided into six groups (n=5). Same designs and types of restorations for the previous test were used for the retention test. All teeth were sectioned perpendicular to the long axis 2mm coronal to the proximal CEJ and then subjected to a standard endodontic treatment. A special milling machine was used for teeth preparation. All-Ceramic endocrowns and crowns were constructed using the Cerec InLab system and cemented with Rely x ARC dual cure adhesive resin cement. The vertical marginal gap distance was measured after cementation using a stereomicroscope. Measurements were made at twenty points for each specimen. In order to mimic the intraoral conditions, all the specimens were subjected to thermal cycling and fatigue loading in a pneumatic fatigue device. Mechanical fatigue was performed for 1,200,000 cycles in a water bath subjected to temperature changes between 5oC and 60oC. The vertical marginal gap distance was re measured at the same points to determine the effect of thermal cycling and fatigue loading. Retention was measured by dislodging the crowns along the long axis of the tooth using a computer controlled universal testing machine. The recorded data were tabulated and statistically analyzed.
<strong>Results: </strong>Regarding the vertical marginal gap distance; endocrowns with 1 mm ferrule showed the statistically significant highest mean gap distance. There was no statistically significant difference between endocrowns without ferrule and post & core supported crowns. For endocrowns with 1 mm ferrule; Empress CAD scored statistically significant higher mean marginal gap values than e.max CAD. There was a statistically significant increase in mean gap distance after thermal cycling and fatigue loading for all test groups. Regarding the retention; endocrowns with 1 mm ferrule showed the statistically significant highest mean retention value. Post & core supported crowns showed statistically significant lower mean value. While, endocrowns without ferrule recorded the lowest mean retention value. In both endocrowns with 1 mm ferrule and post and core supported crowns e.max CAD scored statistically significantly higher mean retention values than Empress CAD, while for the endocrowns without ferrule there was no statistically significant difference between e.max CAD and Empress CAD.
<strong>Conclusions: </strong>Endocrowns represent a successful conservative alternative to post and core supported crowns for restoring mutilated endodontically treated posterior teeth. All tested endocrown designs with both materials proved to have a clinically acceptable marginal gap distances. Preparation geometry for endocrown designs is a crucial factor for the retention of this kind of restorationsThe Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101EFFECT OF BIOPURE MTAD, SODIUM HYPOCHLORITE AND EDTA ON DENTIN MICROHARDNESS: IN VITRO STUDY7697747502510.21608/edj.2017.75025ENWaleedBalubaidGeneral Dentist, Department of Endodontics, Dental Center, King Fahad General Hospital, Jeddah, KSAYoussefAlgarniAssistant Professor of Endodontic, Department of Endodontics, King Khaled University, Abha, KSAAbdulazizBarashidGeneral Dentist, Primary Health Center, Jeddah, KSAJournal Article20200302Objectives: The aim of this study was to evaluate the microhardness of root dentin wall before and after irrigation with BioPure MTAD, 17% Ethylenediamine tetra acetic acid (EDTA) and sodium hypochlorite (NaOCl).<br />Study Design: Sixty-four freshly human extracted single-rooted teeth was used in this study. The teeth were divided into 4 groups, according to the irriganting solution used as final rinse: group (1) BioPure MTAD, group (2) 17% EDTA, group (3) 5.25% NaOCL and group (4) control group (distilled water). The teeth were sectioned longitudinally and prepared for evaluation of microhardness of root dentine before and after irrigation with each irrigants which the baseline microhardness testing was carried out using Vickers Microhardness Tester.<br />Results: The results were statistically analyzed (p<0.05) showing significant difference between all the irriganting solutions in relation to the control group.<br />Conclusion: The EDTA and BioPure MTAD drastically reduced the microhardness of root canal dentin followed by NaOCL.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101SHEAR BOND STRENGTH OF VISCOUS VERSUS RESIN MODIFIED GLASS IONOMERS TO DENTIN CONDITIONED WITH DIFFERENT PROTOCOLS7757827502610.21608/edj.2017.75026ENAsmaa A.YassenAssociate Professor of Operative Dentistry, Faculty of Dentistry, Cairo University, Egypt.Hossam A.AlhussinyLecturer of Operative Dentistry, Faculty of Dentistry, Suez Canal University, Egypt.Dina S.EldineLecturer of Operative Dentistry, Faculty of Dentistry, Misr International University, Egypt)Journal Article20200302Objectives: This study was conducted to examine the effect of conditioning protocols on shear bond strength of viscous glass-ionomer cement (GIC) Versus resin-modified glass-ionomer cement (RMGIC) to dentin. <br />Materials and methods: Forty caries free permanent molars were used. They were sectioned mesiodistally into two halves to obtain 80 specimens that were divided into eight groups (n=10) according to the conditioning protocol. In Group 1 and 2: Dentin was preconditioned with 10% polyacrylic acid either for 10 or 20 seconds and bonded to viscous glass ionomer (Fuji IX GP Extra) using a specially constructed mold (2 mm diameter X 3mm height). In Group 3 and 4: Preconditioning was followed as in group 1 and 2 but RMGI (Fuji II LC) was used. However, in group 5 and 6, dentin was preconditioned with 37% phosphoric acid either for 10 or 20 seconds followed by packing of viscous GI. Group 7 and 8: Preconditioning was done as previous followed by application of RMGI. The specimens were placed in a universal testing machine (Model 3345, Instron Corp., Canton, Mass., USA) with a cross head speed 0.5 mm/min and subsequently tested for shear bond strength SBS (MPa). Statistical analysis was done by using ANOVA and independent t test. <br />Results: SBS values revealed higher bond strength values for RMGI in comparison to viscous GI. Polyacrylic acid groups exhibited higher values than those of phosphoric acid. There was no significant difference in bond strength values of specimens conditioned by the two conditioners for either 10 or 20 seconds(P ≤ 0.05). <br />Conclusions: RMGI experienced high SBS values to dentin. The effect of acid used for dentin conditioning prior to viscous and RMGI can not be overemphasized.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101INFLUENCE OF AXIAL WALL CONVERGENCE ON THE MARGINAL FIT OF ZIRCONIA AND LITHIUM DISILICATE COPINGS AFTER DIFFERENT SURFACE TREATMENT7837927502710.21608/edj.2017.75027ENMaged MohammedZohdyMcs Phd Ain Shams Unversity Lecturer of Fixed Prosthodontis Ain Shams University and British University in EgyptAhmed AbdussalamElaradiMcs Phd of Fixed Prosthodontics Faculty of Dentistry Ain Shams University. Lecturer of Fixed Prosthodontics (ZU)
and S.C.C.L For teeth beautifying.Journal Article20200302Aim: The aim of this research was to study the effect of tooth convergence and internal surface treatment on the marginal fit of Zirconia and Lithium disilicate all-ceramic copings. <br />Materials and Methods: Two stainless steel dies were fabricated simulating a prepared maxillary premolar. The first die had 12°and the second 20° axial wall occlusal convergence. For each material (Zirconia and Lithium disilicate), Thirty non anatomical all ceramic copings were fabricated using inlab MC XL unit (15 copings on each die). For each group of taper, specimens were subdivided according to the technique of the internal surface treatment into three subgroup (5 copings each); air abrasion, tribochemical coating and acid etching. Cervical marginal accuracy was tested before and after cementation using a stereomicroscope. <br />Results: Taper 12° recorded statistically significant higher mean value than taper 20°. Acid etching recorded statistically significant lowest marginal gap mean value. Regardless to ceramic material, taper or cement, the marginal gap after cementation was statistically significant higher than before cementation (p<0.05) <br />Conclusion: Increasing the degree of taper lead to better marginal fit regardless the type of ceramic material. The marginal gap of e.max copings is better than that of zirconia in both before and after cementation. Copings treated with acid etching surface treatment show better marginal adaptation than tribochemical coating and sandblasting surface treatments regardless the type of ceramic material and degree of taper of the preparation.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101EFFECTS OF ADDING SILVER NANOPARTICLES ON THE BONDING OF ADHESIVE SYSTEM TO CEMENT GLASS FIBER POSTS7937987502810.21608/edj.2017.75028ENMohamed I.EbrahimAssistant Professor of Dental Biomaterials, Faculty of Dental Medicine Al Azhar University, Cairo (Boys).AmmarAl ShamraniAssistant Professor of Restorative Dentistry, Dean of Faculty of Dentistry, University of Taif. KSAJournal Article20200302Objective: The present study was conducted to evaluate effects of adding silver nanoparticles with 0.5% nanoparticles on the bonding of adhesive system to cement glass fiber posts. <br />Materials and methods: Twenty human maxillary canines were selected, the coronal portion was sectioned and teeth were endodontically instrumented and obturated with gutta percha. Gutta percha was removed using Largo drills, and then root canal walls of each sample were enlarged with the low-speed burs provided by the manufacturers. The depth of the post space preparation was 10 mm, measured from the cementoenamel junction. The samples were randomly divided into two groups according to adhesive system used. Group A: Adhesive system without additives and Group B: Adhesive system containing 0.5%nanoparticles of silver (NAg). Clearfil SE bond applied without and with additives of (NAg) then cured for 20 seconds using light emitting diodes. RelyX ARC resin cement was introduced into canal and posts were positioned and light-cured for <br />40 seconds then tensile test was done and recorded values of bond strengths in (MPa) were collected, tabulated and statistically analyzed. One way analysis of variance (ANOVA) and Tukey’s tests were used for testing the significance between the means of tested groups which are statistically significant when the P value ≤ 0.05.<br />Results: Tensile strength of adhesive system containing (NAg) (group B) [11.42MPa] had a statistically higher value than adhesive system without (NAg) (group A) [7.99MPa].<br />Conclusions: The results indicate that (NAg) with concentration 0.5% increase tensile bond strength of the adhesive system.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101INFLUENCE OF 2% CHLORHEXIDINE SOLUTION ON COMPRESSIVE STRENGTH, SOLUBILITY AND CALCIUM RELEASE OF CALCIUM ENRICHED CEMENT (CEM)7998047502910.21608/edj.2017.75029ENEmad A.AboalazamPhD, Lecturer, Operative Dentistry Department, Faculty of Dentistry, Suez Canal University.Marwa E.SharaanPhD, Lecturer, Endodontic Department, Faculty of Dentistry, Suez Canal University.Journal Article20200302Calcium enriched mixture cement (CEM) is widely used in endodontics due to its favorable properties. The addition of chlorhexidine to (CEM) material increases its antimicrobial efficiency however; its influence on the properties of this material is unclear. <br />Aim: This study was conducted to evaluate the effect of mixing 2% of Chlorhexidine on the compressive strength, solubility and calcium release of calcium enriched mixture cement. <br />Materials and methods: Two experimental groups were included in this study. The first group, CEM was mixed with CEM cement solution and the second group, calcium enriched mixture cement was mixed with 2% Chlorhexidine solution. Thirty cylindrical samples of 4 mm diameter and of 6 mm height were constructed per each group for assessment of compressive strength at 1, 7 and 15 days intervals 10 samples per each, furthermore, 10 samples of the same dimensions per each group were constructed for assessment of solubility and calcium ion release at 1, 7 and 15 days intervals. <br />Statistical analysis: Data were statistically analyzed using the Kolmogorov-Smirnov and Shapiro-Wilk tests. Independent t-test was used to compare between different mixing solutions on mean compressive strength (MPa), weight loss (μg) and rate of calcium release (ppm). <br />Results: The compressive strength value of CEM cement solution mixed samples was significantly higher than Chlorhexidine mixed ones (P≤0.001). Solubility and calcium ion release significantly increased at 7 and 15 days (P≤0.05) by adding Chlorhexidine to mixing solution. <br />Conclusion: Adding Chlorhexidine to CEM had a negative influence on its compressive strength and solubility rate.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101STRAIN GAUGE ANALYSIS OF TOOTH-IMPLANT-SUPPORTED FDP WITH NON-RIGID CONNECTORS USING DIFFERENT IMPLANT-ABUTMENT CONNECTIONS: INVITRO8058147503010.21608/edj.2017.75030ENRanaSherifAssociate Professor, Fixed Prosthodontics, Faculty of Oral and Dental Medicine, Cairo University.AhmedAbouel FetouhOral Medicine & Periodontology Department; Periodontal , Implant consultant & Clinical Director DGOI
Implantology Specialty Program, Misr International University. Diplomat American Board of Periodontogy.
Tufts University, Boston, USA,LomayaGhanemLecturer, Fixed Prosthodontics, Conservative Dentistry Department, Faculty of Dentistry, Misr International UniversityJournal Article20200302Purpose: To evaluate and compare the strains generated around tooth and implant supported FDPs, including a non-rigid connector, arranged in a linear configuration.<br />Problem Statement: clinical evidence about the connection between the tooth and implant in a fixed dental prosthesis is limited. Certain clinical situations mandate such combination however the prognosis of such treatment is of concern. <br />Methods: Two models were fabricated to mimic missing lower second premolar, the anterior abutment was a natural tooth and the posterior one abutment was an implant attached to its corresponding abutment. 3-unit FDPs with a non-rigid connector and of 8 mm pontic mesio-distal width were constructed, alternating the location of the non-rigid connector at either abutments. Four strain gauges were attached mesially, distally, buccally and lingually to natural tooth and implant. Uniform static axial load of 300 N was applied to the central fossa of the FDP units parallel to the long axis. Strain (µm) induced at both the implant and tooth were recorded and analyzed. <br />Results: Lower mean strains were induced around the tooth on placing the non-rigid connector at the implant side and using cone connection, while around the implant insignificant difference was found. Lower mean strains were induced around both tooth and implant on placing the non-rigid connector at the tooth side and using cone connection. <br />Conclusion: connecting teeth -to-implants must be limited to cases with only one missing tooth. Placing the non-rigid connection at implant side and using cone connection provide favorable strain distribution.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101MICROLEAKAGE PATTERN AT TOOTH-ADHESIVE INTERFACE UNDER METAL-BRACKETS BONDED WITH CONVENTIONAL OR FLOWABLE NANO-ADHESIVE SYSTEMS8158217503110.21608/edj.2017.75031ENRania El-SaadyBadawyLecturer, Dental Materials, Suez-Canal University, Ismailia, EgyptNabil El-DesoukyAbou-ShamaaAssociate Professor, Department of Orthodontics, Suez-Canal University, Ismailia, EgyptWalid ShaabanElsayedLecturer, Oral Biology, Suez-Canal University, Ismailia, EgyptJournal Article20200302Objective: This in vitro study aimed to assess the microleakage at the tooth-adhesive interface underneath metal-brackets, either bonded with a conventional or a nano-adhesive system. <br />Materials and Methods: Dye penetration method was used to evaluate microleakage at the enamel-bracket interface. Twenty freshly-extracted human maxillary and mandibular premolars (average age: 15.47 ± 2.18 years) were randomly divided into two groups (n = 10/group/type of bonding composite). Group 1: metal-brackets bonded with conventional light-cured Transbond XT (3M-Unitek); Group 2: metal-brackets bonded with the light-cured flowable nano-hybrid composite Grandio SO Flow (Voco-Germany) used in combination with a one-step self-etch dual-cured adhesive, Futurabond DC (Voco-Germany). Specimens were thermocycled, immersed in Fuchsin dye, sectioned longitudinally, and evaluated for microleakage. Microleakage was recorded at the adhesive-enamel interface on both occlusal and gingival margins. Statistical analysis was performed using t-test as well as the paired t-tests. <br />Results: Both groups demonstrated microleakage at the adhesive-enamel interface, yet the metal-brackets bonded with the nano-composite Grandio SO Flow (G2) exhibited significantly higher microleakage values at the adhesive-enamel interface compared to brackets bonded with the conventional composite material (p < 0.05). <br />Conclusions: Flowable nano-composites may still not be the adhesive of choice for bracket bonding due to their remarkable microleakage at the enamel-adhesive interface in comparison to conventional light-cured Transbond XT (3M-Unitek).The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101EFFECT OF REPRESSING AND GLAZING ON COLOR REPRODUCTION, TRANSLUCENCY AND SURFACE ROUGHNESS OF LITHIUM DISILICATE GLASS-CERAMICS8238327503210.21608/edj.2017.75032ENAmr S.El-EtrebyLecturer of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt.Journal Article20200302Statement of problem: During heat-pressing of lithium dislilicate glass-ceramics, It is more economical to press several restorations from one ingot at the same time. However, this is often not possible and may result in a considerable amount of leftover material (The sprues and button). It has been reported that the leftover materials after heat-pressing are reused (repressed) in some dental laboratories. Sufficient knowledge about the consequences of such procedure is not available. <br />The issue is thereby raised whether the leftover material should be discarded or reused.<br />Purpose. The aim of the present study was to evaluate the effect of repressing and glazing on the color reproduction, translucency and surface roughness of lithium dislilicate pressable glass-ceramics (IPS e.max Press). As well as to describe the microstructural features present in pressed, and repressed material using Xray diffraction, EDAX and SEM <br />Materials and Methods: Twenty IPS e.max press discs (Pressed and Repressed groups n=10) of 15mm diameter, 1 mm thickness, in shade A3 were fabricated using heat pressed technique. Only the button parts and not the sprues were used for repressing. Color reproduction and translucency were measured using the Vita Easyshade spectrophotometer. Surface roughness was measured using a 3D laser scanning microscope. Crystalline structure and microstructural features present in pressed, and repressed material were described using Xray diffraction, EDAX and scanning electron microscope.<br />Results: Two-way analysis of variance (ANOVA), followed by Tuckey’s HSD test at <br />a significance level of p < 0.05 was performed. Regarding Color reproduction, Translucency and Roughness, significant difference was found between Glazed and Un-Glazed ceramics. <br />No statistical significant difference was found between Pressed and Repressed groups<br />Conclusions: Lithium disilicate glass-ceramic materials have reached their maximum crystallinity prior to repressing. It is important to produce a pore–free structure by only repressing the left over buttons and not the left over sprues. Repressing has no significant effect on Color, translucency and surface roughness and Glazing is crucial to increase color reproduction, translucency and decrease surface roughness of IPS e.max Press.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101THE EFFECT OF REPEATED HEAT-PRESSING ON THE BIAXIAL FLEXURAL STRENGTH AND SURFACE ROUGHNESS OF LITHIUM DISLILICATE GLASS-CERAMICS8338407503310.21608/edj.2017.75033ENAmr S.EL-EtrebyLecturer of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt.LomayaGhanemLecturer, Fixed Prosthodontics, Conservative Dentistry Department, Faculty of Oral and Dental Medicine, Misr
International University, Cairo, Egypt.Journal Article20200302Statement of problem: During heat-pressing of lithium dislilicate glass-ceramics, It is more economical to press several restorations from one ingot at the same time. However, this is often not possible and may result in a considerable amount of leftover material. It has been reported that the leftover materials after heat-pressing are reused in some dental laboratories. Sufficient knowledge about the consequences of such procedure is not available. The issue is thereby raised whether the leftover material should be discarded or reused.<br />Purpose: The aim of the present study was to evaluate the effect of repeated heat-pressing on biaxial flexural strength and surface roughness of lithium dislilicate pressable glass-ceramics (IPS e.max Press). As well as to describe the microstructural features present in fresh-pressed, and repressed material using Xray diffraction, EDAX and SEM <br />Materials and methods: Twenty pressed and repressed samples were prepared following the manufacturers’ recommendations measuring 15 mm × 1 mm per material. Biaxial flexure (piston on 3-ball method) was used to assess strength. X-ray diffraction was performed to identify the crystalline phases, and a scanning electron microscope was used to disclose microstructural features. Also surface roughness was evaluated<br />Results: BFS for pressed and repressed respectively; (375.8± 4.55) and (389.4±12.12) MPa; no significant difference was found between the Pressed and Repressed groups. Surface roughness for pressed glazed and unglazed respectively (0.27±0.05, and 1.14±0.16) – for repressed glazed and unglazed respectively (0.21±0.06 and 1.33±0.20) - for both groups, significant difference was found between Glazed and Un-Glazed ceramics. No statistical significant difference was found between Pressed and Repressed groups. Xray diffraction revealed the material is predominantly crystalline structure; lithium disilicate was identified to be the main crystalline phase, peaks after pressing and repeating pressing are similar, the crystalline phase assemblage did not change; however their radiation intensities (height) has, the dominant peak (highest peak) for the repressed sample is smaller compared to the pressed. EDAX results showed no change in composition between pressed and repressed samples. Microstuructural features SEM displayed a noted increase in crystal dimension after repressing <br />Conclusions. IPS e.max Press left over pressed buttons can be safely reused since repressing does not display consequent negative effects on Biaxial flexural strength and surface roughness, as well as microstructure.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101INFLUENCE OF POST CURING HEAT AND PRESSURE ACTIVATION FOR RESIN COMPOSITE ON IT’S SURFACE HARDNESS8418487503410.21608/edj.2017.75034ENAhmedFawzyLecturer of Operative Dentistry, Suez Canal University.Ahmed Mohamed HosenyFayedLecturer of Operative Dentistry, Misr international University.Journal Article20200302This study was conducted to evaluate the influence of post curing heat and pressure activation of resin composite on it’s surface hardness. <br />Materials and methods: A total of 30 disc specimens, 7mm in diameter and 2mm thick, were constructed from 3 different types of contemporary resin composite restoratives (10 each). For each restorative, half the numbers of the constructed specimens (5 discs) were served as directly cured composite, following their storage in water at 37±1oC for 24h. The remaining 5 specimens of each restorative were subject to post-curing heat and pressure in type B Lisa autoclave for 41 min using B-universal 121 cycle at 122.5ºC and a pressure of 1.16 bar to simulate one simple approach of chair-side indirect composite polymerization. Vickers hardness numbers were determined using a micro-hardness tester (Wilson ® Hardness Tester, Model Tukon 1102, Buehler, Lake Bluff, IL, USA) using a load of 50 gf for 15 seconds dwell time. The Vickers’s hardness number (N/mm2) was recorded as an average of six readings, three from each surface (top and bottom) for each specimen. <br />Results: ANOVA was used for the effect of additional heat activation and type of resin composite on it’s surface hardness. It was found that the use of an additional heat activation and type of resin composite (matrix type and degree of loading) had a statistical significant effect on VHN of resin composite tested. <br />Conclusion: The post-curing heat and pressure improves the surface hardness of the tested resin composites.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101IN VITRO MICRO SHEAR BOND STRENGTH OF DIFFERENT ADHESIVE SYSTEMS TO SOUND, CARIES AFFECTED AND SCLEROTIC DENTIN8498577503510.21608/edj.2017.75035ENAshraf ElsayedNasrAssistant Professor of Operative Dentistry, Cairo UniversityAhmedFawzyLecturer of Operative Dentistry, Suez Canal UniversityJournal Article20200302This in-vitro study compared the Micro Shear bond strength of different adhesive systems to prepared specimens of sound, caries affected and sclerotic dentin. <br />Materials and methods: A total of 90 freshly extracted human molar teeth were collected, 30 prepared for each type of dentin either sound, caries affected or sclerotic dentin. Every type of the prepared dentin groups was subdivided into five subgroups, each receive one of the tested adhesives (n=6). The teeth were embedded vertically in cylindrical Teflon mold of 2 cm height and 20 mm internal diameter using a chemically cured cross-linked acrylic resin, so as to have the full crown projecting above the surface of acrylic resin. Teeth were ground off using model trimmer with low speed and copious water coolant in direction perpendicular to the long axis of the tooth to expose the dentin surface. All the tested adhesive materials were applied on prepared dentin surface (Sound, carious, and sclerotic) together with resin composite material according to manufactures instructions. The prepared specimens were stored immediately in deionized water for 24 hours at 37°C before testing procedures. Micro shear bond strength (µSBS) was tested using the micro shear bond apparatus (DL200 Emic Sao Jose de Pinhas, PR, and Brazil). µSBS MPA= Shear force (N)/cross sectional area (mm2). <br />Results: ANOVA was used for the effect of type of dentin and adhesive system used. Sound dentin showed the highest µSBS followed by carious dentin and at last came sclerotic dentin. For the adhesive system total etch showed the highest µSBS followed by two step self-etch with etch and rinse and two step self-etch and at last came one step self-etch with etch and rinse and one step self-etch. <br />Conclusion: Total-etch adhesive revealed higher micro shear bond strength than self-etch adhesive irrespective of the type of dentin tested, in addition, the etch and rinse step improves micro shear bond strength of self-etch adhesive with different type of dentin.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101EFFECT OF NATURALLY DERIVED COLLAGEN CROSS-LINKERS ON DENTIN BONDING AT CLINICALLY RELEVANT EXPOSURE TIMES8598697503610.21608/edj.2017.75036ENNabawy A.AlrobeigyAssistant Professor, Department of Dental Biomaterials, Faculty of Dentistry, Tanta University, Tanta, Egypt.Journal Article20200302Purpose: To investigate the effect of treatment the demineralized dentin with two naturally derived collagen cross-linking agents on resin-dentin shear bond strength using three clinically relevant treatment times.<br />Materials and methods: 60 mid-coronal dentin specimens were randomly divided into two divisions (n=30) and either was treated with one of two cross-linking agents: 25% grape seed extract (GSE) and 25% ascorbic acid (ASA). The teeth of each division were further divided into three groups (n=10) according to the time of cross-linking agent application: 30 sec, 60 sec, and <br />90 sec. Additionally, 10 teeth were used as a control group (no treatment). After cross-linkers treatment and adhesive application, composite (Filtek Z250 XT) cylinders (3 mm diameter × 2 mm length) were built on all dentin surfaces. All specimens were stored in distilled water for 24 hours at 37˚C and then subjected to shear stress in a universal testing machine. Failure patterns were observed using a light microscope at 10X. The micromorphology of the fractured surfaces of selected specimens was evaluated using SEM. SBS data (MPa) were statistically analyzed by two-way ANOVA and t-test.<br />Results: Both cross-linking agents resulted in a significant (P<0.0001) increase in resin-dentin SBS in comparison to control, regardless of application time. SBS values of both cross-linking agents were significantly increased by increasing their application time from 30 to 90 sec, while they were not affected, between other treatment times. There was no significant (P = 0.5) differences in SBS values between the two cross linkers at each corresponding treatment time.<br />Conclusions: Resin-dentin SBS can be improved after treatment of demineralized dentin by GSE, and ASA cross-linking agents at a clinically relevant treatment times.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101ANTI BACTERIAL EFFECT OF DIFFERENT ADHESIVE ROOT CANAL SEALER8718747612710.21608/edj.2017.76127ENMedhat TahaElfaramawyLecturer of Endodontics. Faculty of Dentistry. Ain Shams UnivShady AliHusseinLecturer of Endodontics. Faculty of Dentistry. Ain Shams UnivJournal Article20200307Aim of the study: To compare the antibacterial effect of ActivGPsealer (Glass Ionomer based) (Brasseler, Savannah, USA) versus AD seal (Resin based sealer) (META, Chungcheongbuk-do, Korea) and AH 26 sealer (Resin based sealer) (Densply, USA) against E-faecalis using agar diffusion method. Samples were classified into 3 groups according to the material used Group 1: Activ GP sealer, Group 2: AD seal and group 3; AH 26. Each group was classified into three subgroups according to the observation periods (1 day, 3 days and 7 days). Each group consisted of 7 agar plates implanted with E-faecalis strain. 3 holes were created in each agar plate each hole contained one tested material. The results showed that the AH Plus exhibited the largest inhibitory zone followed by Activ GP which exhibited the anti bacterial activity only after 3 days while AD seal exhibited no antibacterial activity. It has been concluded that the antimicrobial activity of AH Plus was greater than Activ GP, which were more efficient in bacterial inhibition than AD seal.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101THE ANTI BACTERIAL EFFECT OF DIFFERENT FORMULATIONS OF CALCIUM HYDROXIDE AGAINST E-FAECALIS8758797503810.21608/edj.2017.75038ENMedhat TahaElfaramawyLecturer of Endodontics. Faculty of Dentistry. Ain Shams Univ.Shady AliHusseinLecturer of Endodontics. Faculty of Dentistry. Ain Shams Univ.Journal Article20200302Aim of the study: To compare the antibacterial effect of Nano-calcium hydroxide ( Nanostreams, Cairo, Egypt) mixed with saline versus conventional calcium hydroxide (GAMA dental lab,Cairo, Egypt) with saline and calcium hydroxide paste with iodoform (Cal plus) (Apexion, Karala, India) against E-faecalis using agar diffusion method. Samples were classified into 3 groups according to the material used. Each group was further divided into 3 subgroups according to the observation time (1day, 3days and 7 days). Each group consisted of 7 agar plates implanted with E-faecalis strain. 3 holes were created in each agar plate, each hole contained one tested material. The results showed that Nano calcium hydroxide had the largest inhibitory zone of E faecalis in agar diffusion test over all observation periods followed by conventional calcium hydroxide. The calcium hydroxide mixed with iodoform had the least average inhibitory zone. Calcium hydroxide Nano particles have superior anti microbial activity against E faecalis compared to other tested materials. The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101COLOR MASKING MEASUREMENT FOR CERAMIC COATING OF TITANIUM USED IN DENTAL IMPLANTS8818907503910.21608/edj.2017.75039ENKhaldounAjlouniProfessor, Department of Restorative Science, Baylor College of Dentistry, Texas A&M Health Science Center, Dallas, TX.WaleedElshahawyLecturer, Department of Fixed Prosthodontics, Faculty of Dentistry, Tanta University, Egypt.RaedAjlouniProfessor, Department of Restorative Science, Baylor College of Dentistry, Texas A&M Health Science Center, Dallas, TX.AbdelfattahSadakahProfessor, Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Egypt.Journal Article20200302Statement of problem: The dark metal color showing through the periimplant soft tissue as a result of poor implant placement or thin gingiva and progressive bone resorption is a common problem in implant dentistry. <br />Purpose: The purpose of this study was to test the color masking effect of porcelain applied on titanium used in fabricating the polished collar of tissue level implants to solve this problem.<br />Material and Methods: Type 4 commercially pure titanium disks and five porcelain dentin shades (A2, A3, B2, C2, and D3) were used. Ten titanium disk specimens per porcelain shade were air abraded and ultrasonically cleaned. Porcelain was condensed directly on the specimens, then fired and finished (1200 grit SiC paper). The color (L*a*b* values) of the polished specimens were measured using reflective spectrophotometer. The specimens were then ground and polished in 0.1 mm increments. Color was measured and ΔE values were calculated at each increment until the thickness at which the color coordinates start to change. ΔE greater than 3.3 was considered as a significant color mismatch detectable by the human eye. The data (n=10) was statistically analyzed by ANOVA/Tukey test at the 95% confidence level (α = .05).<br />Results: ΔE was less than 3.3 as long as the ceramic thickness was ≥ 0.5 mm for A2, A3, B2, and C2 shades. For D3, ΔE was less than 3.3 as long as the ceramic thickness was ≥ 0.4 mm.<br />Conclusions: The minimum ceramic thickness required to block the underlying titanium color is 0.5 mm for all shades except D3 which only needs 0.4 mm ceramic thickness. L* decreased with thickness increase. Redness a* and yellowness b*increased with thickness increase.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101FAILURE TORQUE OF A NOVEL CERAMIC-NECK TITANIUM IMPLANT8918987504010.21608/edj.2017.75040ENWaleedElshahawyLecturer, Department of Fixed Prosthodontics, Faculty of Dentistry, Tanta University, Egypt.RaedAjlouniProfessor, Department of Restorative Science, Baylor College of Dentistry, Texas A&M Health Science Center, Dallas, TX.KhaldounAjlouniProfessor, Department of Restorative Science, Baylor College of Dentistry, Texas A&M Health Science Center, Dallas, TX.AbdelfattahSadakahProfessor, Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Egypt.Journal Article20200302Statement of problem: Dental implants are typically made of titanium. However, with the current systems in the market, it is common for the implant neck to show through the gingival tissues as a black or dark grey line and/or as a grayish discoloration of the periimplant soft tissue.<br />Purpose: The purpose of this study was to test a new implant design; the ceramic neck implant is a novel implant design for tooth replacement. The key component of this novel design is the ceramic shell that covers the polished collar of the tissue level titanium implant and masks its dark color, which gives an appearance that mimics natural dentition. The main aim was to determine the maximum torque for fracturing the ceramic shell and compare it to clinical implant insertion torque value.<br />Material and Methods: Thirty type 4 commercially pure titanium endosseous implants of three different diameters (3.3, 4.1, 4.8 mm) were used in this study. Porcelain was applied in 0.5 mm thickness on the polished collar of each implant as determined in a previous article. Axial-torsional universal testing machine was used to twist the implants at X N.cm/s until failure. The data (n=10) were statistically analyzed by ANOVA/Tukey test with a significant level α = .05. The maximum torque for each diameter group was also compared to optimum clinical implant insertion torque value of 35 Ncm (control) using one sample T-test (P<.001). <br />Results. None of the tested groups had a fractured ceramic shell at all. Instead, the implants carriers have fractured at certain torque levels. Therefore, the fracture of the implants carriers was selected as the maximum (failure) torque value. There was statistical difference for the failure torque (Mean ± SD) between 3.3 mm diameter and the other two diameters (P<.001) (F=15.6) while no statistical difference was found between the 4.1 mm and 4.8 mm diameters (p=.106). A statistically significant difference was found between failure torque of any one of the tested groups and the clinical insertion torque (P<.001).<br />Conclusions: Ceramic shells did not fracture. Instead, implants carriers have fractured at certain torque levels. These levels were sufficiently higher than the clinical torque values. This means that there are fewer chances that a fracture might happen while inserting the novel ceramic neck implant and/or the abutment.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101CANDIDAL COLONIZATION AND PALATAL DENTURE BASE ADAPTATION IN RELATION TO DENTURE BASE MATERIALS AND THEIR PROCESSING TECHNIQUES8999067612510.21608/edj.2017.76125ENHala MohamedAbd El HameedAssistant Professor of Prosthodontics, Faculty of Dentistry, Suez Canal UniversityJournal Article20200307<strong>Purpose: </strong>The purpose of this research was to compare between the effect of denture base materials and their processing techniques on palatal denture base adaptation and candidal colonization.
<strong>Materials and methods: </strong>Thirty identical denture bases was constructed by silicon mold which was made from a educational edentulous maxillary cast . Thirty maxillary stone casts were obtained by pouring hard dental stone in the previous silicon mold . Sheets of wax with 2mm thickness, each were adapted to their corresponding stone casts then divided equally into three groups. <strong>Group I: </strong>Ten maxillary heat cured acrylic resin denture bases processed by long cycle hot water bath curing technique. <strong>Group II</strong>: ten maxillary acrylic resin denture bases processed by microwave energy. <strong>Group III: </strong>Ten maxillary monomer free thermoplastic resin denture bases processed by sabelix injecting system. Palatal denture base adaptation and candidal colonization were evaluated. The data was recorded and statistically analyzed.
<strong>Results</strong>: The results of this study showed that statistically there was significant difference in palatal denture base adaptation between the tested groups as(p=0.024). The least mean gap (stone thickness) at the posterior palatal seal area was found in Acrifast denture base resin (G III) followed by GI. The least mean numbers of candidal colonies for the three groups was found in Acrifast denture base resin (G III) followed by GI . Statistically there was highly significant difference of candidal colonization between the three tested groups as(p<0.001).
<strong>Conclusion: </strong>Based on the limits of this study, it could be concluded that injectable monomer free thermoplastic resin denture base material is preferred to minimize candidal colonization, enhance the accuracy of denture base adaptation and increase the opportunity for obtaining successful complete dentureThe Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101EVALUATION OF STRESSES AND RETENTION IN TWO DIFFERENT TYPES OF BAR ATTACHMENT USED IN IMPLANT RETAINED MAXILLARY OBTURATOR9079177524410.21608/edj.2017.75244ENAmr Mohamed IsmailBadrLecturer of Prosthodontic Department, Minia UniversityAhmed Gamal AhmedHassanLecturer of Prosthodontic Department, Minia UniversityJournal Article20200303Purpose: The aim of this study was to compare the stresses and retention force of two different attachment systems in implant retained maxillary obturator.<br />Material & Methods: an acrylic model was constructed to simulate edentulous case with maxillary defect and three implants were inserted in the pre-maxillary region. The obturator was constructed with the first design bar with equator attachment (BEA) and screwed to the implants. The retention was measured at the base line and after 90,270,540,810,1080,1620,2160 cycles of insertion and removal respectively. Then the second design bar and clip attachment was constructed, screwed and retention testing procedures repeated as that for the first design. Universal testing machine was used for measuring the retentive forces of each retainer type. The vertical static load of 60 and 90 N was applied (loading machine) at three loading points on the obturator prosthesis for the two bar designs. The readings were tabulated and statistically analyzed.<br />Results: Two-factor ANOVA followed by pair-wise Newman-Keuls post-hoc tests were performed to detect significance between variables (Attachment type and aging). Bar and clip design recorded slightly lesser retention force than that of BEA at base line and at all cycles of insertion and removal but with no significant difference between the two designs. But regarding the effect of aging within each group; there was a significant difference at different cycles of insertion and removal. But regarding the stress analysis Bar and clip recorded to some extent less micro-strain values than BEA in most of surfaces at different points of loading.<br />Conclusion: The retention force of Bar and clip was slightly lesser than BEA at any given cycle of insertion and removal. Reduction of mean retentive force continues to occur over time within each group. Bar and clip recorded less micro-strain values than BEA at most of the surfaces specially when applying the load on the posterior intact side.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101ORAL REHABILITATION OF PATIENT WITH SICKLE CELL ANEMIA AND DENTAL ANOMALY: CASE REPORT9199237524510.21608/edj.2017.75245ENDalia A.AbuelenainDepartment of Restorative Dentistry, King Abdulaziz University Faculty of Dentistry, Jeddah, Saudi Arabia,Journal Article20200303Sickle cell anemia patients with dental anomalies represent a difficult challenge for the prosthetic dentist. Proper treatment planning with the medical and dental management of these patients are important prerequisites for successful results. This case report describes a full-mouth rehabilitation of a sickle cell anemia patient with worn-down dentition including the treatment planning, medical consultation, correction of vertical dimensions of occlusion, preparation, and restoration with porcelain fused to metal crowns.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101CRESTAL BONE LOSS USING DIFFERENT STUD ATTACHMENTS IN DISTAL EXTENSION CASES9259317524710.21608/edj.2017.75247ENHesham I.AlmEldeenLecturer, Prosthodontics Dept. Faculty of Oral and Dental Medicine Future University, Cairo, Egypt.Journal Article20200303The duality of support that characterizes distal extension removable partial dentures is often characterized by time-dependent adverse changes in both the abutment teeth and edentulous areas. Consequently, adjunctive implant has been proposed for mandibular class I and II removable partial denture designs. This current study evaluated the effect of locator attachment system and ball abutment with O-ring female metal housings in implant retained mandibular partial overdenture by measuring peri-implant crestal bone level. Twenty partially edentulous male patients exhibiting bilateral distal extension edentulous areas were selected. Two implants were installed in the first molar region following the two stage surgical technique. Patients were randomly divided into <br />2 equal groups; Group 1 locator attachments were used and Group 2 ball attachments were used. The mesial, distal, buccal and lingual marginal bone height around the implants was evaluated using cone beam CT. The measurements were carried out at insertion, six and twelve months post insertion. The results of this study showed a statistically significant increase in crestal bone height loss around the implants in both groups during the follow up period. In conclusion, ball -retained mandibular overdenture are associated with more marginal bone compared to locator abutments.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101THE EFFECT OF RECIPROCAL ARM ON THE SUPPORTING STRUCTURES OF THE ABUTMENTS IN CASES RETAINED BY UNILATERAL ATTACHMENT9339397524910.21608/edj.2017.75249ENHesham I.AlmEldeenLecturer, Prosthodontics Dept. Faculty of Oral and Dental Medicine Future University, Cairo, Egypt.Journal Article20200303Ten patients with kennedy class I classification utilizing OT unilateral extracoronal attachment were randomly divided in two groups using split mouth research design. Group I (without bracing arm) and group II (with a bracing arm on a prepared ledge at the survey line of the abutments). Radiographic evaluation of the abutments was made at time of denture insertion, 6months, 12months, 18 months, and 30 months after denture insertion to measure the bone height changes around the abutments. The results obtained showed a statistically significant difference in bone loss around the abutment teeth between the two groups. In Conclusion patients rehabilitated with OT unilateral extracoronal attachment with a bracing arm showed less vertical bone loss around the abutmentsThe Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101ESEM ANALYSIS OF ENAMEL SURFACE MORPHOLOGY ETCHED WITH ER,CR:YSGG LASER AND PHOSPHORIC ACID: IN VITRO STUDY9419477525010.21608/edj.2017.75250ENSahar AbdEl HalimAssistant Professor, Operative Dentistry Department, Misr University for Science and Technology, Egypt.RashaRaafatLecturer of Conservative Dentistry, Faculty of Dentistry, Cairo University, Egypt.AmrElGanzoryDDS,American Board of Prothodontics, Chicago ILL. Master of laser SinceJournal Article20200303Objectives: The aim of the present study was to evaluate the etching pattern of Er,Cr:YSGG and conventional etching on prepared samples of human enamel by environmental scanning electron microscope (ESEM).<br /> Materials and Methods: Forty five freshly extracted human upper premolars were used; the teeth had been extracted for orthodontic reasons and were collected and stored in a solution of 0.1% (wt/vol) thymol. The teeth were mounted vertically in a self-cure acrylic cylinder. One clinician prepared all the teeth, in each tooth, a 4x4 mm area was treated in middle third of the buccal surface. The teeth were divided into three groups according to type of etching techniques (n=15).Group(A): enamel etched with 37% phosphoric acid for 30 s, thoroughly rinsed with distilled water for 60 s and gently air dried.; Group (B): enamel was irradiated with Er,Cr:YSGG laser ablated with an energy output of 4.5 watt/30hz and Group (C):enamel was irradiated with Er,Cr:YSGG laser ablated with an energy output of 4.5 watt/20hz. In group b & c Er,Cr:YSGG laser (2.78 μm wavelength) used for 15 sec at 45degree angulations working distance 5mm on a square size 4x4mm on buccal surface. Micro-morphological changes of enamel surface were evaluated using an environmental scanning electron microscope at X250 & X1500 magnification.<br /> Results: In this study, laser with 30 Hz reveals a definite change in the surface of the enamel, most of the enamel prisms are interrupted showing an irregular outline. However laser with 20 Hz showed the ultra-structural appearance of enamel nearly similar to that of conventionally etched enamel with 37 percent phosphoric acid. <br />Conclusion: Within the limits of this in vitro study, both conventional acid etching & laser 20 Hz etching showed nearly similar effect on enamel surface, so the laser-etching can be successfully used as an alternative to the conventional acid-etch. On the other hand laser 30 Hz etching failed to induce an effect on enamel surface comparable to that of acid etching and therefore can’t be used as substitute for the conventional acid –etch.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101EFFECT OF CALCIUM CHANNEL-BLOCKERS ON CLINICAL OUTCOMES OF IMPLANT RETAINED OVERDENTURE IN HYPERTENSIVE PATIENTS9499617525110.21608/edj.2017.75251ENAhmed M.Alam-EldeinLecturer, Prosthodontic Department, Faculty of Dentistry, Tanta UniversityEmad A.MabroukLecturer, Prosthodontic Department, Faculty of Dentistry, Tanta UniversityAmer M. NasrMostafaLecturer, Prosthodontic Department, Faculty of Dentistry, Tanta University.Journal Article20200303Purpose: Calcium channel-blocking agents are used extensively for the management of hypertension. Gingival overgrowth around natural teeth has been previously reported in the literature with patients taking calcium channel-blocking agents. There are limited scientific documentations illustrating its effects around dental implants. This study compared the effects of Calcium channel-blocking agents (Amlodipine) and angiotensin receptor blockers (Valsartan) on dental implants retaining overdentures in hypertensive patients clinically and radiographically after two years of function. <br />Materials and Methods: Twenty completely edentulous male hypertensive patients wearing mandibular overdentures retained by two implants (3.6*12mm Dentium Two– piece (Ball type) dental implant, Dentium Implant System, Korea) were included in this study, Patients were equally and randomly divided into two groups, Group (I) were managed by Amlodipine according to their physician to control the hypertension. Group (II) were managed by Valsartan according to their physician to control the hypertension. Each case was evaluated clinically concerning plaque index, gingival index, probing depth and implant stability by using OSSTELL ISQ and radiographically concerning marginal bone loss at baseline (overdenture insertion) and after <br />6, 12 and 24 months. Data were collected, tabulated and statistically analyzed using t-Student test.<br /> Results: No statistical significant difference was found between the two groups (P≥0.05). <br />Conclusions: Based on the limitations of the present study and although no statistical difference was found between the effect of Amlodipine and Valsartan on dental implants under overdentures. Peridontium around implants in hypertensive patients managed by calcium channel blockers Amlodipine was affected more than that managed by Valsartan.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101APICAL TRANSPORTATION AND CENTERING RATIO IN S-CURVED CANALS USING NITI FULL ROTATION VERSUS RECIPROCATION SHAPING TECHNIQUES9639737525210.21608/edj.2017.75252ENMohammed HamdiAtteiaAssociate Professor of Endodontics, Department of Endodontics, Faculty of Oral and Dental Medicine, Cairo
UniversityJournal Article20200303Objectives: The aim of the present study is to compare apical transportation, centering ratio, changes in working length and canal axis ratio in the S-shaped canals using full rotation versus reciprocation shaping techniques. <br />Methodology: Twenty-five S-curved artificial canals were used. Five canals were used for the pre-instrumentation radiographs and records. The other 20 canals were divided into two groups (10 canals each); G1: One-Shape (OS) and G2: Wave-One (WO) files. Canals were prepared, and obturated. Post-obturation radiographs were taken with the same parameters of the pre-instrumentation records. Pre- and post-instrumentation digital images were evaluated with AutoCAD program analysis. <br />Results: Full rotation using OS files showed significantly far less apical transportation than WO reciprocation (P < 0.001). There was no statistically significant difference in centering ratio between full rotating and reciprocating files (P > 0.05). WO produced higher percentage increase in working length than OS files. Both techniques could not maintain the original canal <br />axis ratio. <br />Conclusions: Within the parameters of this study, Single-file shaping technique with full rotation instruments produced significantly less transportation and less violation of the working length than did the reciprocating WO instruments. Both techniques violated the original canal axis ratio and had nearly equal centering ratio, however, none of them was perfectly centered.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101EFFICACY OF INCISAL PREPARATION DESIGNS ON THE FRACTURE RESISTANCE OF TWO CAD/CAM LAMINATE VENEERS9759847525310.21608/edj.2017.75253ENEmanEssamInas TMotaweaHeba EEltayebJournal Article20200303Statement of problem: Mechanical properties are cardinal for the long-term clinical success of laminate veneer restorations. The most common failure is fracture and debonding, in which unfavorable occlusion and articulation play an important role. Nonetheless, the effect of different incisal preparations on the behavior of veneers remains controversial.<br />Objective: The purpose of this study was to evaluate the fracture load of two different CAD/CAM laminate veneer materials: resin nano-ceramic [lava ultimate] and lithium disilicate glass ceramic [IPS e-max CAD], with two different incisal preparation designs [butt-Joint and incisal overlap]; using both in-vitro and finite element analysis studies. <br />Materials and Methods: A total of 20 maxillary central incisors were used in this study. The samples were divided into two main groups (n=10), according to the CAD/CAM material used. Ten laminate restorations were constructed for each group following the manufacturer’s directions with the two preparation designs (5 samples each), then cemented on their corresponding teeth. Fracture load was recorded for each specimen using the universal testing machine. Meanwhile, Finite element analysis study was performed to assess the in-vitro observations. <br />Results: The results revealed that incisal overlap design with Lava ultimate laminate veneers recorded the highest mean fracture strength value (395 ±37.18 N). This was supported by the finite element results that showed that the incisal overlap design with lava ultimate laminate veneers had the lowest Von Mises stress (30.75 MPa). <br />Conclusions: Within the limitations of the present study, it was concluded that the butt-joint and incisal overlap designs demonstrated different mechanical behaviors with regard to the two different restorative materials. The incisal overlap design tolerated stresses better than the butt-joint design with both materials. Also, the incisal overlap design with resin nano-ceramic laminate veneers had the best stress distribution. Nevertheless, both types of CAD/CAM materials and different incisal preparation designs used could be considered strong enough to withstand the average anterior masticatory biting forces.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101FRACTURE RESISTANCE OF CAD/CAM FABRICATED IMPLANT - SUPPORTED ALL - CERAMIC CROWNS CEMENTED ON READY AND CUSTOM MADE ZIRCONIA ABUTMENTS98510027525410.21608/edj.2017.75254ENHanaa ISallamJournal Article20200303Statement of the problem: Despite their outstanding esthetic characteristics, the adequacy of implant-supported all-ceramic crowns under occlusal loads in the posterior segment of the jaw remains questionable. <br />Aim of the study: Evaluation of the fracture resistance of different CAD/CAM fabricated implant-supported all-ceramic monolithic posterior crowns cemented on ready and custom made zirconia abutments. <br />Materials and methods: 30 internal connection titanium dummy implants were embedded in epoxy resin and randomly divided into three groups (n=10 each) according to the crown material used; Group I: Polycrystalline ceramic (Katana Zirconia), Group II: Hybrid ceramic (Vita Enamic) and Group III: Lithium disilicate glass ceramic (IPS e.max CAD).All crowns were CAD/CAM fabricated as monolithic maxillary right first premolar.In each group, five crowns were cemented on ready made zirconia abutments (subgroup A) while the other five were cemented on custom made zirconia abutments (subgroup B). All samples were thermocycled (5o to 55o,10 seconds dwell time) then compressively loaded under axial static load till fracture using a universal testing machine with a loadcell of 5 kN at a cross-head speed of 1mm/min. The load required to fracture was recorded in Newton and failure modes were visually analyzed. Statistical analyses were performed by Two-way ANOVA and Tukey’s post-hoc test.( P ≤ 0.05)<br />Results: Fracture resistance of implant-supported all-ceramic monolithic posterior crowns was statistically significantly affected by the ceramic crown material and abutment type (P<0.001). Either with ready or custom-made zirconia abutments; zirconia crowns recorded the statistically significantly highest fracture resistance mean value followed by IPS e.max CAD ones while Vita Enamic crowns recorded the lowest values with no statistically significant difference between them and IPS e.max CAD crowns. Zirconia and Vita Enamic crowns cemented on custom made abutments recorded statistically significantly higher mean fracture resistance values than those cemented on ready made one. However, IPS e.max Cad crowns cemented on both abutment types showed statistically insignificant difference. Different failure modes were observed among the tested ceramic crowns without fracture of any abutment.<br />Conclusions: All tested implant-supported all-ceramic monolithic posterior crowns cemented on ready and custom made zirconia abutments had the potential to withstand the physiologic occlusal forces in the premolar region with the superiority of the zirconia crowns cemented on custom made zirconia abutments.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101STRESS ANALYSIS OF REMOVABLE PARTIAL DENTURES OF DISTAL EXTENSION CASES FABRICATED OF TWO RECENT AESTHETIC CAD/CAM PROSTHETIC MATERIALS VERSUS CONVENTIONALLY MANUFACTURED METALLIC RPDs100310177525510.21608/edj.2017.75255ENElsayed GadEidJournal Article20200303Recently, there are different types of esthetic materials used for RPDs framework fabrication some of which are applicable for CAD/CAM system. Distal extension base removable partial dentures exhibit composite type of support, which leads to movement of the denture base under load application and transmission of high amount of stresses to the supporting structures.<br />Aim: The current study was conducted to analyze the stress transmitted to the abutment teeth and the residual ridge by three types of RPDs of different materials; Conventionally manufactured metallic Co-Cr RPDs, and two thermoplastic RPD materials; Acetal (Polyoxymethylene; POM) and a modified PEEK (Poly-Ether-Ether-Ketone) material (BioHPP; Biocompatible high performance polymer) distal extension RPD frameworks both manufactured by computer aided design and computer aided manufacturing (CAD/CAM) system as two esthetic prosthetic materials. <br />Methods: Strain gauge technology was used to assess micro-strains induced to the denture supporting structures for the three fabricated RPDs groups. Master casts of ten patients with mandibular bilateral distal extension (the remaining teeth extending from left 1st premolar to right 1st premolar) were used so that each cast was duplicated into 4 casts; three of these casts were used for manufacturing of acetal and BioHPP frameworks by CAD/CAM system, and conventional Co-Cr RPD frameworks. The fourth cast was duplicated to obtain acrylic cast with movable acrylic abutment teeth over which the three RPDs (two metal-free and one metallic RPDs) of each case were seated and tested. The microstrain of the supporting structures was recorded on bilateral and unilateral loading.<br />Results: On bilateral loading: Mean value of microstrains recorded at the abutments was -63.75 and -18.75 at the ridge for Co-Cr group; For acetal group, it was -91.25 at the abutments and 18.94 at the ridge; For BioHPP group, microstrain was -106 at abutments, while it was 37.15 at the ridges. On unilateral loading: For Co-Cr group, microstrains recorded at right abutment was -52, while it was -6 at left abutment, and at right ridge it was -16.5 and -2 at left ridge; For acetal group, microstrains recorded at right abutment was -176 and -10 at left abutment, and at right ridge it was 17 and 4.5 at left ridge; For BioHPP group, microstrains recorded at right abutment was -284, while it was 10.5 at left abutment, and at right ridge it was 50.5 and 6.5 at left ridge.<br />Conclusion: Co-Cr RPDs group showed the least stresses transmitted to the supporting tissues followed by Acetal RPDs, while BioHPP RPDs group showed the highest mean values of microstrain induced to the abutment teeth and the residual ridge.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101COMPARISON BETWEEN THE EFFECT OF CONVENTIONAL REMOVABLE PARTIAL DENTURES AND TELESCOPIC REMOVABLE PARTIAL DENTURES ON POCKET DEPTHS AND ALVEOLAR BONE HEIGHT OF ABUTMENT TEETH101910267525610.21608/edj.2017.75256ENAhmedFayyadLecturer of Prosthodontics, Cairo UniversityNaglaNassouhyLecturer of Prosthodontics, Cairo UniversityJournal Article20200303Objective: this study was conducted to compare the effect of the conventional removable partial dentures (RPDs) and telescopic partial dentures on pocket depths and alveolar bone height of abutment teeth after a follow-up period of one year.<br />Materials and Methods: twenty eight patients with mandibular bilateral free-end saddle were selected for this study, with canines and first premolars as last standing abutments on both sides and an opposing maxillary dentulous arch. They were randomly divided into two groups, group I receiving a conventional RPD, and group II receiving a telescopic partial denture. CAD/CAM technology was used for the fabrication of Polymethylmethacrylate patterns for both copings and frameworks for the two groups followed by casting in the conventional manner. Radiographic bone height measurements and pocket depth measurements were performed for the two groups at denture delivery and after one year.<br />Results: there was no significant difference in percentage bone loss and pocket depth between the two groups after one year. However, only group II showed a significant increase in pocket depth after one year of follow-up. There was also an increase in bone loss in both groups after one year but it was not significant. <br />Conclusion: Minor changes in pocket depths and alveolar bone height were observed in both groups. However, the telescopic partial denture showed signs of gingival inflammation and increased pocket depths, while the conventional removable partial denture showed more favorable results.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101MECHANICAL PROPERTIES OF THE NEW KETAC™ UNIVERSAL GLASS IONOMER RESTORATIVE MATERIAL: EFFECT OF RESIN COATING102710357525710.21608/edj.2017.75257ENTarek A.SolimanLecturer of Dental Biomaterials, Faculty of Dentistry, Mansoura University, EgyptMaha S.OthmanLecturer of Operative Dentistry, Faculty Dentistry, Cairo University, EgyptJournal Article20200303Statement of the problem: Clinical performance and survival rates of posterior high strength GICs are questionable. A new generation of conventional glass-ionomer restorative material <br />(Ketac™ universal) without coating has been launched recently for restoring class I and II cavities without investigations.<br />Objectives: This study was conducted to evaluate the mechanical properties of a new generation of conventional glass ionomer (Ketac™ universal) for restoring posterior stress bearing areas.Furthermore, the effectiveness of resin coating on Ketac™ universal GIC was evaluated.<br />Materials and Methods: Three types of conventional glass ionomer restorative materials were selected for this study (Ketac™ Universal; KU, Ketac™ Molar; KM and Fuji IX GpFast; FIXF). Each GICs material specimens were prepared according to manufacturer’ instructions and distributed randomly into two groups (N=30) (uncoated and coated groups) and then conditioned in distilled waterat 370C for 24 hours. The flexural strength,compressive strength, and hardness tests for each material were evaluated using a universal testing machine. Furthermore, additional representative un-coated and coated specimens for each material were prepared for their characterization under scanning electron microscope. Data were analysed by multivariate ANOVA. Bonferroni post hoc test was used for multiple comparisons. Paired t-test was used to detect significant differences between un-coated and coated GICs. Interactions between GICs materials and coating were also performed. P-value is significant if it was less than .05.<br />Results: The highest significant flexural strength, compressive strength and hardness values were noticed with Ketac universal and the lowest was noted with FIXF. Also, only significant improvement in the flexural and compressive strength of FIXF when resin coating was applied.<br />Conclusions: KU represents an encouraging line of higher clinical longevity of GICs’ filling material in stress bearing areas. Also the resin coating has no significant effect on the tested mechanical properties of KU GICs.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101EFFECT OF DIFFERENT SURFACE TREATMENTS AND RESIN TYPES ON BONDING TO TRANSLUCENT ZIRCONIA103710467525810.21608/edj.2017.75258ENAhmed M.HamdyAssociate Professor, Fixed Prosthodontic Department, Faculty of Dentistry, MSA University.SaharAbdel-WahabAssociate Professor, Fixed Prosthodontics Department, Faculty of Oral and Dental Medicine, Al-Azhar University.Journal Article20200303Purpose: This in vitro study measured the adhesive properties of 10-MDP and MPE containing resin cements, using two types of zirconia surface treatments; selective infiltration etching(SIE) and airborne particle abrasion (APA) to translucent zirconia (3M, ESPE) .<br />Statement of Problem: Due to translucent zirconia modified composition (alumina content reduced to tenth of its weight) bonding strength to different resin cements after different surface treatments should be investigated adequately . <br />Materials and Methods:Sixty sintered Lava plus high translucency disks(3M,ESPE)were randomly divided into three study groups according to their surface treatment: (a) polished surface (control group); (b) air borne particle abraded (grit blasted) with 50 µm aluminum trioxide (APA); and (c) selective infiltration etching (SIE). Zirconia disks (15x2mm) were then bonded to 60 composite resin disks (8x4mm) using two different resin composite cements (Clearfil SA and Rely X). Resin-zirconia adhesion strength was evaluated using the microshear bond strength test (MSBS) after 24 hour of storage in deionized water at 37˚C. One way ANOVA and Scheffé s post-hoc tests were used to analyze the data (p<0.001). Then fractured samples were studied under SEM and classified according to failure pattern.<br />Results: Different types of resin cement and surface treatment significantly influenced the MSBS (P<0.001). The highest mean MSBS values were recorded with MDP containing resin cement (Clearfil SA) in both SIE (26.18 ±1.12 MPa) and APA (21.67±1.34) groups. Bond strength values were reduced significantly in control group when using the two types of cements. Regarding failure pattern, MDP groups showed cohesive and MPE and control groups showed adhesive type.<br />Conclusion: SIE and APA in combination with 10-MDP containing resin cement established a strong durable bond to zirconia substrates than MPE groups. SIE and APA showed significant higher bond strength values than control groups.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101A CLINICAL STUDY OF THE INTERNAL FIT OF ZIRCONIA AND GOLD PLATINUM CAD/CAM FRAMEWORKS FIXED DENTAL PROSTHESIS104710547525910.21608/edj.2017.75259ENSaharAbdel WahabAhmed MHamdyJournal Article20200303Statement of problem: A new CAD/CAM technology for the fabrication of metal copings for metal –ceramic restorations has been introduced. However, no sufficient data on the internal fit of metal- ceramic restorations produced by this method is available yet.<br /> Purpose: This study was performed to compare the internal gap between abutment teeth and posterior fixed dental prosthesis (FDPs) fabricated utilizing yttria-stabilized tetragonal zirconia polycrystals and Gold Platinum metal ceramic alloy frameworks. <br />Materials and Methods: A randomized controlled clinical trial was performed, twenty FPDs were fabricated with yttria –stabilized zirconia poly crystals (Y-TZP –IPS e.max zir CAD) and metal –ceramic (MC Au-Pt) as follow(n=10): thirty patients were randomly selected for internal fit measurements. The internal fit of the FPDs frameworks were measured using replica technique. Data was analyzed with (ANOVA) test, followed by Tukey’s post hoc test.<br />Results: The internal gap, according to the thickness of the replica, was measured under magnification at the following locations: cervical, axial, and occlusal (cusp-tips and central). The internal gaps of FPDs with zirconia frameworks were significantly larger in cervical, axial, and centro-occlusal regions (cervical: 69.549± 10.484 µm vs. 60.493 ± 15.940 µm axial : 75.678 ± 8.996 µm vs. 53.356 ± 12.916 µm ; and centro-occlusal: 78.159± 10.272 µm vs. 69.343 ± 4.446 µm). The cervical gaps next to the pontics were significantly larger compared with those of the outer walls in both types of FPDs (zirconia: mean difference 71.655 ± 4.583 µm; metal-ceramic: mean difference 52.891± 5.665 µm ). <br />Conclusion: Posterior three-unit FPDs milled zirconia frameworks fabricated according to the manufacturer’s specifications exhibited larger internal gaps than those constructed using milled Gold Platinum metal-ceramic technique. <br /> Clinical implications: Both milled Gold platinum metal ceramic, and zirconia may be an alternative for 3- unit frameworks in terms of internal fit. Zirconia showed inferior results but within the range of clinical acceptability.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101INFLUENCE OF COBALT CHROMIUM FRAMEWORK FABRICATION TECHNIQUES ON MARGINAL ACCURACY AND FRACTURE BEHAVIOR OF IMPLANT-SUPPORTED METAL CERAMIC BRIDGES105510687526010.21608/edj.2017.75260ENHanaa I.SallamAssociate Professor of Fixed Prosthodontics, Faculty of Oral and Dental Medicine, Cairo University.Journal Article20200303Statement of problem: Marginal fit and structural integrity are keys for long term success of implant supported restorations. Little information is available regarding precision of marginal adaptation and fracture behavior of implant supported metal ceramic bridges with recently introduced milled Cobalt Chromium frameworks. <br />Aim of the study: Evaluation of marginal accuracy (before and after porcelain application) and fracture resistance of implant supported metal ceramic bridges with Cobalt Chromium (Co-Cr) frameworks fabricated using the new computer aided designing /computer aided manufacturing (CAD/CAM, soft milling/post sintering) technique in comparison to the conventional casting technique.<br />Materials & Methods: A total of 10 epoxy resin models were constructed into which two titanium dummy implants were inserted in each model and received straight titanium abutments. 10 Co-Cr cement retained frameworks were fabricated on the implant models, 5 with the new CAD/CAM soft milling/ post sintering technique (group I) and the other 5 with the lost wax casting technique (group II). All frameworks were veneered with porcelain by the layering technique. Vertical marginal gap distance between the Co-Cr frameworks and the implant abutments was measured using a stereo microscope at 16 predetermined points/abutment before and after porcelain application. Then metal ceramic bridges were cemented onto their corresponding abutments with temporary resin cement. Samples were loaded compressively under static vertical load till fracture in a universal testing machine with a loadcell of 5 kN at a cross-head speed of 1 mm/min. The load required to fracture was recorded in Newton. Fracture modes of all samples were visually analyzed. Data were statistically analyzed using the repeated measures ANOVA test for vertical marginal gap distance results (P<0.05) and the students t- test for fracture resistance results (P < 0.05). <br />Results: Framework fabrication techniques as well as porcelain application was statistically insignificantly affecting the vertical marginal gap distance as indicated by the repeated measures ANOVA test (P>0.05). Bridges with CAD/CAM fabricated frameworks recorded the lowest statistically insignificant vertical marginal gap distance mean value before porcelain application (24.63±4.27µ), while those with cast frameworks recorded the highest statistically insignificant vertical marginal gap distance mean value after porcelain application (25.21±7.08µ). Implant supported metal ceramic bridges with cast frameworks showed higher fracture resistance mean value (1608.56±215.04 N) than those with CAD/CAM fabricated frameworks (1392.73±160.75 N), the difference between groups was statistically insignificant as indicated by Student’s t -test (P >0.05). <br />Conclusions: CAD/CAM soft milled/post sintered Co-Cr frameworks may be considered promising alternative to conventional cast frameworks for implant supported metal ceramic bridges in terms of marginal accuracy and fracture resistance.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101THE EFFECT OF CHITOSAN AND PROPOLIS IRRIGATION ON ROOT DENTIN MICROHARDNESS106910757526110.21608/edj.2017.75261ENAbeer AbdelhakimElgendyAssociate Professor of Endodontics, Faculty of Dentistry Ain Shams UniversityJournal Article20200303Introduction: The aim of the present study is to evaluate comparatively the action of 0.2% chitosan, 4% propolis, 2.6 % NaOCl and 17% EDTA on human root dentin microhardness. <br />Methods: Twenty recently extracted single-rooted mandibular premolar teeth were selected. The roots were split longitudinally into 2 parts (40 specimens). The specimens were randomly divided into 4 groups and were treated with 0.2% chitosan, 4% propolis, 2.6 % NaOCl and 17% EDTA immediately after the initial baseline microhardness measurements. A standardized volume of 2 ml of each solution was used for 5 minutes. The reference microhardness values of untreated specimens were initially measured with a Vickers indenter under a 50-g load and a 10-second dwell time. Posttreatment microhardness values were obtained in the same manner as the initial ones. The decrease in microhardness was calculated as a percentage. Data were analyzed statistically by 1-way analysis of variance (P = .05) and the post hoc Tukey test for multiple comparisons at the same level of significance. Differences between pretreatment and post-treatment microhardness were statistically analyzed by using the t-test with a P value of .05 <br />Results: After treatment, all solutions significantly decreased the microhardness of root dentin (P < .05) however both 0.2% chitosan, 4% propolis significantly decreased dentin microhardness compared to 2.6 % NaOCl and 17% EDTA. <br />Conclusion: All the tested irrigation decreased root dentin microhardness however the effect of either 0.2% chitosan or 4% propolis decreased root dentin microhardness more than 2.6% NaOCl or 17% EDTA.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948463Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20170101CLINICAL AND RADIOGRAPHIC EVALUATION OF MAXILLARY SMALL DIAMETER IMPLANT SUPPORTED SCREW RETAINED RESTORATIONS: A TWENTY-FOUR MONTHS FOLLOW-UP107710877526210.21608/edj.2017.75262ENHeba E.KhorshidLecturer, Department of Prosthodontics, Faculty of Oral and Dental Medicine, Cairo University.Nora M.ShetaLecturer, Department of Prosthodontics, Faculty of Oral and Dental Medicine, Cairo University.Journal Article20200303Purpose: The Target of this work was to clinically and radiographically evaluate the marginal bone loss and stability of Small Diameter Implants in comparison with Standard Diameter implants in implant supported screw retained maxillary prostheses. <br />Materials and Methods: In this study, a total of seventy two implants were placed in twelve patients with completely edentulous maxillae. The patients were randomly grouped into two groups: Group A received small diameter implant and Group B received standard diameter implants. For each patient, six implants were placed in the lateral incisor/Canine region, first premolar and first molar region. Bone height measurements as well as Osstell RFA (resonance frequency analysis) measurements around each implant were performed at zero, four, eight and twenty-four months after definitive prostheses delivery.<br />Results: In this study, a total of 72 implants were installed (36 small diameter implants and 36 standard diameter implants). At the end of the 24 months follow-up period, statistical analysis showed no statistically significant difference in the crestal bone height and ISQ (implant stability quotient) values (p≤0.05) between the Group A and Group B.<br />Conclusion: Within the limited observation period and the number of patients included in this study, it may be concluded that the use of small-diameter implants appeared to be predictable if proper clinical guidelines are followed and appropriate prosthetic restorations are provided. Small-diameter implant supported screw retained restorations have success rate that appear to be comparable to that of standard diameter implants. This might thus be an efficient, low-cost solution, avoiding extensive bone augmentation procedures and reducing the surgical complexity of implant rehabilitations.