The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Effect of Different Temperatures on Flexural Cyclic Fatigue Resistance of 2Shape and OneShape Rotary Endodontic Instruments3553647911110.21608/edj.2020.79111ENMarwa MahmoudBedierAssociate Professor of Endodontics, Endodontic Department, Faculty of Dentistry, Cairo University, EgyptShaimaa IsmailGawdatAssociate Professor of Endodontics, Endodontic Department, Faculty of Dentistry, Cairo University, EgyptJournal Article20200325Objectives: The aim of the present study was to evaluate the effect of the different temperatures on the flexural cyclic fatigue of 2 Shape and OneShape rotary endodontic files.<br />Materials and Methods: Forty-rotary endodontic files were divided according to the type of instrument used and the surrounding temperature (n=10); 2Shape and OneShape rotary endodontic files rotated in a custom made simulated canal model block fixed to a beaker containing water with temperature adjusted to either 37 °C or 60 °C. Time was recorded from the beginning of rotation until the fracture was detected, then the number of cycles to failure (NCF) and the length of the fractured segment (FL) were evaluated. Two representative samples were photographed under scanning electron microscopy. Two-way Analysis of Variance (ANOVA) was used to study the effect of the type of instrument used and temperature on the number of cycles to failure and the length of the fractured segment. <br />Results: 2Shape rotary endodontic files used at 37° C showed statistically significant highest mean of number of cycles to failure compared to 2Shape at 60°C (P<0.001), then OneShape used at 37°C, and finally the OneShape used at 60 °C (P<0.011).<br />Conclusions: 2 Shape showed more resistance to flexural cyclic fatigue than OneShape, and high temperature seemed to have a reducing effect on the flexural cyclic fatigue resistance of the both tested rotary endodontic instruments.<br /> Objectives: The aim of the present study was to evaluate the effect of the different temperatures on the flexural cyclic fatigue of 2 Shape and OneShape rotary endodontic files.<br />Materials and Methods: Forty-rotary endodontic files were divided according to the type of instrument used and the surrounding temperature (n=10); 2Shape and OneShape rotary endodontic files rotated in a custom made simulated canal model block fixed to a beaker containing water with temperature adjusted to either 37 °C or 60 °C. Time was recorded from the beginning of rotation until the fracture was detected, then the number of cycles to failure (NCF) and the length of the fractured segment (FL) were evaluated. Two representative samples were photographed under scanning electron microscopy. Two-way Analysis of Variance (ANOVA) was used to study the effect of the type of instrument used and temperature on the number of cycles to failure and the length of the fractured segment. <br />Results: 2Shape rotary endodontic files used at 37° C showed statistically significant highest mean of number of cycles to failure compared to 2Shape at 60°C (P<0.001), then OneShape used at 37°C, and finally the OneShape used at 60 °C (P<0.011).<br />Conclusions: 2 Shape showed more resistance to flexural cyclic fatigue than OneShape, and high temperature seemed to have a reducing effect on the flexural cyclic fatigue resistance of the both tested rotary endodontic instruments.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Minimally invasive endodontics and permanent restorations of endodontically treated teeth: literature review3653787911210.21608/edj.2020.79112ENMohammad I.Al-ObaidaAssociate Professor / Consultant Endodontist, King Saud University, College of DentistryJournal Article20200325The primary goal of endodontic therapy is the long-term survival of a functional tooth through the prevention and/or treatment of apical periodontitis. However, successful endodontic outcomes depend on many factors, such as the structural integrity of the tooth after root canal preparation and the quality of the final restoration. The field of endodontics is continuously changing due to the introduction of new techniques and technological advances. Currently, minimally invasive endodontics is considered as the recommended approach during root canal therapy, with permanent restorative decisions saved for the postoperative period. Various materials and techniques have been developed and/or proposed to increase the life span of endodontically treated teeth while maintaining adequate root strength and maintaining the balance between biological, mechanical, adhesive, functional, and esthetic parameters. This critical review aims to assess the literature on recent trends in conservative endodontic treatment and adhesive dentistry for the restoration of endodontically treated teeth. The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Effect of attachment height on chewing efficiency for mandibular over denture wearer3793877911310.21608/edj.2020.79113ENHala MohamedAbd El HameedAssociate Professor of Prosthodontics, Faculty of Dentistry Suez Canal UniversityJournal Article20200325Purpose: The intent of this research was to study the effect of attachment height on chewing efficiency of the patients wearing mandibular overdenture <br />Materials and methods: Twelve male patients had completely edentulous maxillary and mandibular ridges, were elected to perform this study. All Patients received complete maxillary denture and mandibular over denture retained by two implants with locator abutments divided into two equal groups according to the length of the locator attachment.<br />GroupI: the patients were received locator abutment with 1mm in height.<br />Group II: the patients were received locator abutment with 3mm in height<br />Colored chewing gum used for estimation of chewing efficiency of the patients by the help of special software programs. The data was reordered and statistically analyzed at( two, four &six) weeks from over denture insertion .<br />Results: between groups the results of this study reveled that Group II representing higher means of Delta E values than group I throughout different follow-up periods. These values were statistically significant at four and six weeks from over denture insertion at p ≤ 0.05 .Within groups the results of this study presented that the means of Delta E values for group I& group II increase throughout different follow-up periods. These values were statistically non significant at all observation periods for group I and statistically significant for group II at p ≤ 0.05. <br />Conclusion: Within the restrictions of this study it could be concluded that, the attachment height affects chewing efficiency of the patient.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Effect of occlusal scheme on bolus transport during feeding for complete denture wearers3893957911410.21608/edj.2020.79114ENAbdallah M.IbrahimLecturer of Removable Prosthodontics, Faculty of Dentistry, Mansoura University, EgyptJournal Article20200325Objectives: This study was aimed to evaluate the influence of different occlusal schemes on bolus movement during feeding for complete denture wearers. <br />Methods: Thirty completely edentulous patients were participated in this study. All patients were randomly classified in two equal groups. Group I received a complete denture with bilateral balanced occlusal scheme (BBO) and group II received a complete denture with lingualized balanced occlusal scheme (LBO). Patients were instructed to chew and swallow ¼ of cookie (coated with pudding and barium powder) with and without denture. Masticatory duration, number of chewing cycles, number of swallow, oropharyngeal residue, and penetration aspiration observation were measured by using videofluoroscopic assessment at baseline, 2 weeks and 3 months after denture insertion.<br />Results: Penetration of food into the larynx was significantly founded in edentulous patients without complete dentures. After 3 month of denture insertion, LBO group showed a statistically significant reduction in masticatory duration, and number of chewing cycles (p<0.05) compared to BBO group.<br />Conclusion: The occlusal scheme has been found to be important in swallowing function as lingualized balanced occlusal scheme improve chewing ability and oral preparatory stage of swallowing in comparison to bilateral balanced occlusal scheme after 3 month of denture insertion.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Treatment of Dentinal Hypersensitivity using desensitizing agents plus soft laser irradiation. A Randomized Comparative Clinical Trial3974037911510.21608/edj.2020.79115ENMona M.GhoneimAssociate Professor of Restorative Dentistry, Faculty of Dentistry, Alexandria university, Egypt.NayerAboelsaadAssociate Professor of Periodontology, Faculty of Dentistry, Beirut Arab University, LebanonJournal Article20200325This study aimed to evaluate the efficacy of diode laser combined with two in-office desensitizing agents 8% Arginine-CaCO3 and 1.23 NaF varnish on reducing dentine hypersensitivity (DH) in periodontitis patients. <br />Materials and Methods: Forty patients having stage I and Stage II periodontitis were selected according to the criteria of AAP (2017) with complaint of (DH) after routine periodontal therapy . Patients were randomly divided into two groups: group1- received NaF varnish then diode laser application at 1 W (PW) ,(CW) for 30 seconds using 320µ fiber. Group-2, treated with 8%Arginine-CaCO3 plus same laser irradiation. Each tooth received three application Dentine hypersensitivity evaluation was by tactile, air-blast, and thermal stimuli and measured using VAS scores. The patient’s response was recorded at baseline, one month and 3 month after the application.<br />Results and conclusions: The results were statistically analyzed, and it was found that 8% Arginine-CaCO3 plus laser treatment was more effective than 1.23% NaF-varnish plus laser at time intervals. Sensitivity score differences between the groups were statistically significant at one and three months. The 8% Arginine-CaCO3 group exhibited statistically significant reduction in dentine hypersensitivity on three stimuli at baseline to one and three months. It was concluded that 8% Arginine- CaCO3 plus laser irradiation is more effective than 1.23% NaF varnish plus laser irradiation in reduction of patients’ pain in periodontitis patients.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Enhancing the Osseodensification Concept Using Platelet-Rich Fibrin in Sinus Lifting for Maxillary Class II Kennedy Cases4054137911610.21608/edj.2020.79116ENAhmed MohamedEl-SayedAssociate professor of Removable Prosthodontics, Faculty of Dentistry, Cairo UniversitySherif AlySadekLecturer of Removable Prosthodontics, Faculty of Dentistry, Cairo University.Journal Article20200325Objectives: This study aimed to enhance Osseo densification by using Platelet-rich fibrin (PRF) on sinus lifting of maxillary implant in class II partially edentulous cases. <br />Materials and Methods: fourteen maxillary class II partially edentulous patients were selected and divided into two groups. Single implant was inserted in the edentulous region with closed sinus lifting technique for each patient in both groups, for group I implant was placed with the Densah bur drilling system together with PRF while in group II other implant was placed with that same system without PRF. Implant primary stability was measured using Resonance Frequency Analysis by Osstell immediately after torqueing the implants and every two weeks for 2 months. Rate of bone formation was followed up by taking CBCT after implant loading and followed up for one year. <br />Results: No significant difference was found regarding Osstell values at all follow up appointments for both groups. Regarding the bone formation, the group with PRF there was significant difference than the group without PRF. <br />Conclusions: Using Densah burs in closed sinus lifting consider very safely and effective technique and using PRF as grafting material in closed sinus lifting enhancing rate of bone formation.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)202001013D Finite Element Stress Analysis Of Different Abutment Materials in Screw, Implant and Cortical Bone4154217911710.21608/edj.2020.79117ENAmany M.KorselAss,Prof, Fixed Prosthodontics Department, Faculty of Dentistry, Tanta University, EgyptJournal Article20200325Purpose: To give an idea of different implant-abutment material behavior by evaluation the stress distribution of material type on surrounding structures of single implant- supported restorations.<br />Materials and Methods : A 3D Finite Analysis method used for evaluate the distribution of stress in implants were examined using different abutment materials: Titanium(Ti) - (Implant Blue Sky, Bredent, Senden, Germany), Zirconium(Zr) (Implant Blue Sky, Bredent, Senden, Germany), High Performance Polymer (BioHPP)-( Sky elegance abutment, Bredent, Senden, Germany). Fiber reinforced composite(FRC)( World Headquarters sigma-aldrich.) Loading applied and as loading five nodes top an monolithic ceramic restoration. Mises and deflection values through screw and implant and cortical bone were calculated. <br />Results : The results of the analysis showed that the abutment material affect stress distributions where the least stresses created on bone with BioHPP abutment (16.5Mpa) followed with FRC abutment (17.3Mpa). While its effect on screw showed clear differences, the least stresses created with Zirconia abutment (67.9Mpa) followed by Titanium abutment (85.29Mpa) then FRC (117.32Mpa) finally abutment. These showed BioHPP FRC abutments nearly have very close and less effort bone. The highest stresses on implant showed with FRC and BioHPP abutments as follow (142.4, 122.4 Mpa) while the least stresses with Zirconium and Titanium abutments <br />(126.5, 137.45 Mpa).<br />Conclusion: BioHPP and FRC abutment transmit less stress on the bone than Titanium and Zirconium . KEY WORDS : implant abutment,BioHPP , FRC,Stress analysisThe Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Effect of preheating and ultrasonic energy on penetration of low viscosity enamel resin infiltrant4234277911810.21608/edj.2020.79118ENMona M.GhoneimAssociate Professor of Restorative Dentistry, Faculty of Dentistry, Alexandria university, Egypt.Moustafa N.AboushelibProfessor of Biomaterials, Faculty of Dentistry, Alexandria university, EgyptHebatullahDawodResearcher at Biomaterials Lab, Faculty of Dentistry, Alexandria University, EgyptRowan A.GaberResearcher at Biomaterials Lab, Faculty of Dentistry, Alexandria University, EgyptNourhanRaafaResearcher at Biomaterials Lab, Faculty of Dentistry, Alexandria University, EgyptHagar M.AliResearcher at Biomaterials Lab, Faculty of Dentistry, Alexandria University, EgyptRania S.AbdelrahmanInstructor in Operative Department, Faculty of Dentistry, Alexandria University, EgyptJournal Article20200325Objectives: to determine the depth of resin infiltrated hybrid enamel after application of TTEMA/TEGDMA resin infiltration agent enriched with nano-hydroxy apatite applied on early carious enamel lesions.<br />Materials and Methods: Sound maxillary centrals were coated with a nail varnish, leaving a window of 4 mm × 4 mm on buccal surface of sound and intact enamel. All specimens were subsequently immersed in a demineralizing solution to produce artificial enamel lesions then etched with a mixture of 2% chlorhexidine and 10% hydrochloric acid. After washing and drying the enamel was coated with a low viscosity TTEMA/TEGDMA resin infiltration agent followed by light polymerization. The effect of addition of 10% nano-hydroxy apatite, preheating at 45ºC, and ultrasonic activation was tested in separate groups. Sectioned specimens were examined under a stereomicroscope equipped with a high-resolution digital camera for determining of the depth of penetration of the low viscosity resin in microns (α=0.05).<br />Results: Data analysis revealed significant difference in depth of enamel hybrid layer between the tested groups (F=14.2, P<0.001). Average penetration depth was 185 ± 17 µm for TTEMA/TEGDMA resin infiltration agent. Addition of 10% nano-hydroxy apatite reduced penetration depth to 141± 19 µm. On the contrary, preheating and ultrasonic activation increased penetration depth to 211± 13 µm and 221 ± 12 µm respectively.<br />Conclusions: Within the limitations of this study, the penetration depth of TTEMA/TEGDMA resin infiltration agent was significantly influenced by addition of nano-hydroxy apatite particles. Preheating and ultrasonic activation increased penetration depth significantly.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101The Marginal Fit and Fracture Resistance of Four‑Unit Monolithic and Bi -layered Zircon Fixed Dental Prosthesis4294387911910.21608/edj.2020.79119ENAmany M.KorselAss,Prof, Fixed Prosthodontics Department, Faculty of Dentistry, Tanta University, EgyptJournal Article20200325Purpose: This study aimed to evaluate the fit and fracture resistance of monolithic and Bi -layered zircon fixed dental prosthesis. <br />Materials and Methods:20 master models composed of two metal abutments and embedded vertically in autopolymerizing acrylic resin blocks to mimic clinical conditions for a four‑unit FDPs. Twenty FDPs were fabricated and divided into two groups (n = 10): group A, bilayered zirconia four‑unit FDPs; group B, monolithic zirconia four‑unit FDPs. The marginal gap of each retainer specimens was measured for both groups at 18 sites on the margin of the master dies using a digital microscope. Paired t-test was used to evaluate mean marginal gap changes. One-way ANOVA and post hoc tests were also employed for comparison among 2groups (α=.05). the Samples in each group were cemented to their corresponding model and then underwent artificial ageing by thermocycling of 5000/cycle. The fracture resistance test was done using universal testing machine at cross-head speed of 1 mm/min. Statistical analysis of the results and comparison between each two groups were performed using independent t,test (significance: P ≤ 0.05). <br />Results: Marginal gap was increased after porcelain veneering. The mean marginal gap values after veneering in the layering group (52.06 µm) was higher monolithic group (21.4 µm) in molar die margin CONCLUSION Three veneering methods altered the marginal fit of zirconia copings. All ceramic crowns made through two methods revealed clinically acceptable marginal fit.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Influence of Different Materials and Preparation Designs on Marginal Adaptation and Fracture Resistance of CAD/CAM Fabricated Occlusal Veneers4394527912010.21608/edj.2020.79120ENZeinab N.EmamAssociate professor, Fixed Prosthodontics Department, Faculty of Dentistry, Cairo University, Egypt, Associate
professor, Fixed prosthodontics Division, Oral and maxillofacial Department, Faculty of Dentistry, Umm Al Qura University, KSANada AliA. AleemAssistant Professor, Conservative and Restorative Dentistry Department, Faculty of Dentistry, Umm Al Qura University, KSA.Journal Article20200325Statement of the problem: Thin, posterior occlusal veneers establish a conservative approach to conventional complete coverage restorations. Information about the proper material and its effect upon fracture resistance, which may affect the durability of the restoration, is still unknown.<br />Objective: This in-vitro study was carried out to assess the effect of variable materials and preparation designs on marginal fit and fracture resistance of CAD/CAM fabricated occlusal veneers.<br />Materials and Methods: A total number of sixty freshly extracted maxillary first premolars were collected. The selected teeth were inspected for being intact, non-restored and free from caries, cracks and severe occlusal erosive lesions. The teeth were chosen to be of comparable bucco-lingual and mesio-distal dimensions. All teeth were mounted along their long axis in epoxy resin templates. A standardized occlusal preparation (simulating advanced occlusal erosion) including enamel removal, dentin exposure and immediate dentin sealing were made. Teeth were randomly assigned equally to three test groups (n=20) according to the material of the CAD/CAM blocks used for fabrication of the occlusal veneers, group (I): Lithium di-silicate glass ceramics (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein), group (II): Hybrid all-ceramic material (VITA ENAMIC, VITA Zahnfabrik, Germany) and group (III): Nano ceramic reinforced resin composite (BRILLIANT Crios, Coltène/Whaledent AG, Switzerland). Each group was then sub-divided into two equal sub groups (n=10) according the preparation design used for occlusal veneer, where subgroup (1): represented the minimally invasive occlusal veneer preparation resembling occlusal erosion. Subgroup (2): represented occlusal veneer preparation with marginal chamfer. Teeth were restored with 1.0 mm thickness occlusal veneers. Vertical marginal gap distance for all occlusal veneers was measured using stereomicroscope. Following Vertical marginal gap distance measurements, the samples were subjected to cyclic fatigue loading for 60000 cycles which is equivalent to six months clinical service. Then vertical marginal gap distance for all samples was recalculated after fatigue loading testing. Fracture resistance test was done using universal testing machine. The load to fracture for all samples was recorded in Newton. Data were collected, tabulated and statistically analyzed. Results: Two ways ANOVA test results showed that CAD/CAM restorative materials used in this study, regardless of preparation design had a statistically significant effect on mean fracture resistance, whereas, preparation design regardless of type of material used had no statistically significant effect on mean fracture resistance. With Nano ceramic reinforced resin composite, hybrid ceramic and Lithium Di-silicate glass ceramics before or after cyclic fatigue loading; there was no statistically significant difference between marginal gap distances for the two preparation designs. <br />Conclusions: All the tested CAD/CAM materials showed fracture loads above the recommended minimum fracture strength for posterior restorations. CAD/CAM composite resin posterior occlusal veneers were superior to ceramic ones in terms of fracture resistance. All tested materials in both preparation designs whether before or after fatigue loading, exhibited marginal gap distance not exceeding that described in the literature as acceptable range.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Color stability and Microstructure Changes of Two Pressable Ceramics after Repeated Firing protocols4535687912110.21608/edj.2020.79121ENZeinabEmamAssociate Professor, Fixed Prosthodontics Department, Faculty of Dentistry, Cairo University, Egypt, Associate Professor, Fixed Prosthodontics Division, Oral and Maxillofacial Department, Faculty of Dentistry, Umm Al-Qura University.Shereen M.El SayedAssociate Professor, Fixed Prosthodontics Department, Faculty of Dentistry, Cairo University, Egypt, Associate Professor, Fixed Prosthodontics Division, Oral and Maxillofacial Department, Faculty of Dentistry, Umm Al-Qura University.Journal Article20200325Statement of the problem: it is important that researchers gather more information regarding the effect of repeated firing on optical properties and microstructure of all ceramic restoration<br />Purpose: The aim of this in vitro study was to investigate the effect of repeated firing on color stability and microstructure changes using X-ray diffraction, EDAX and SEM of two pressable ceramics.<br />Methods: A total number of forty eight freshly extracted maxillary central incisors were collected. The selected teeth were cleaned and disinfected in 0.5% sodium hypochlorite solution, then stored in distilled water for maximum two weeks until the testing began. The roots of the selected teeth were serrated with a disc for retention. The teeth were mounted vertically into auto-polymerizing acrylic resin material. Full coverage all-ceramic preparation was performed for all teeth. The prepared teeth were randomly divided into two equal test groups (n=24) according to the all-ceramic materials used for crown fabrication as follows: Group I: IPS e-max Press (LD): Twenty four prepared teeth were restored with pressable lithium di-silicate glass ceramics (IPS e.max press, Ivoclar, Vivadent AG, Schann, Lieshtenstein). Group II: Celtra Press (ZL): Twenty four prepared teeth were restored with pressable zirconia-reinforced lithium di-silicate glass ceramics (Celtra Press, Dentsply, Sirona.). Then samples were subjected to repeated firing cycles up to five firing cycles. Samples were divided into four equal subgroups (n= 6), according to the number of firing cycles performed for each sample. Subgroup (A) : Control samples, subgroup (B):1st firing cycle ,subgroup (C): 3rd firing cycle, Subgroup (D): 5th firing cycle. All ceramic crowns fabrication was done according to manufacturer instructions for each material. For each crown the L *, a* and b* was measured using spectrophotometer (Vita Easy shade) by placing the probe tip on the central part of the labial surface of the crown, the colorimetric values of ΔL*, Δ a* and Δb* were measured from differences in the respective L*, a*and b* values. The total color difference ΔE* were measured at each firing cycles subgroups for each group of ceramic materials. Data were collected, tabulated and statistically analyzed. Microstructural analysis for the two tested all ceramic materials was examined by X-ray diffractometer, scanning electron microscopy, the elemental chemical composition as well as quantitative analysis was measured by energy dispersive X -ray spectroscopy (EDAX) .This analysis was done after the control firing and the 5th firing cycle.<br /> Results: Regardless of the ceramic material, statistically significant color differences were resulted by repeated firing as follows ; perceptible but yet clinically acceptable for lithium di-silicate glass ceramics (LD), whereas, perceptible and clinically unacceptable for zirconia reinforced lithium di-silicate(ZL). The microstructure of the two pressable ceramic materials (LD, ZL) turned out to be unstable after repeated firing cycles for both ceramic materials.<br />Conclusions: Color stability is affected by repeated firing for both tested materials. Repeated firing is not recommended for ziconia reinforced lithium di-silicate because color changes (ΔE = 4.18) are exceeding the clinical acceptability.Repeated firings might result in microstructral changes within the ceramic materials.Microstructure analysis through SEM, EDAX and XRD is a reliable analytical approach.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101The Effect of Different Remineralizing Agents on Laser Bleached Enamel4694837912310.21608/edj.2020.79123ENAya ElsayedSamahaBDS, MSc, DDS, Operative Dentistry Department, Faculty of Dentistry, Ain Shams UniversityDina Hazem HassanGomaaBDS, MSc, DDS, Oral Biology Department, Faculty of Dentistry, Ain Shams UniversityJournal Article20200325One of the most required esthetic measures for patients with teeth discoloration or those who strive to have a beautiful smile and appearance is bleaching. The objective of this study is to analyze enamel morphological changes, chemical composition and microhardness following the application of 35% hydrogen peroxide, utilizing two various protocols for laser activation and the application of 4 different remineralizing agents. <br />Materials and methods: In this study, 40 extracted human lateral and central incisors were chosen where the researcher categorized teeth into 2 groups consisting of 20 incisors, using two different laser-activated bleaching protocols. The researcher then subdivided each group into 4 subsets consisting each of 5 incisors where 4 remineralizing agents were applied to each bleached subset. Enamel surface morphology was studied by ESEM. Calcium and Phosphorus content were measured by EDAX and microhardness Vicker’s test was performed to study the alteration in enamel hardness. Pre- and post-demineralization (bleaching) investigations were conducted and then they were repeated following remineralization. <br />Results: ESEM revealed the improvement of enamel surface morphology in the remineralized groups except in (HD) and (LD) groups. After remineralization, all groups had a higher weight percent of calcium (Ca) and phosphorus (P) levels than its levels after demineralization except in groups (HD) and Vicker’s hardness number in all groups showed significant increase except (HD) and (LD). <br />Conclusion: The use of remineralizing agents containing casein phosphopeptide-amorphous calcium phosphate, fluoride or hydroxyapatite nanoparticles could improve the enamel morphology, microhardness and chemical composition of laser bleached enamel.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101INFUENCE OF TOOTH-IMPLANT SUPPORTED TELESCOPIC OVERDENTURES WITH CERVICAL CLEARANCE ON SUPPORTING STRUCTURES OF UNILATERAL DISTAL EXTENSION RIDGE4854947912410.21608/edj.2020.79124ENSahar KH.Abdel-BaryAssistant Professor of Removable Prosthodontics, Misr University For Science and TechnologyNasser HusseinAliAssistant Professor of Fixed Prosthodontics, Misr University For Science and TechnologyJournal Article20200325Aim: This study aimed to evaluate the influence of tooth -implant supported telescopic partial overdentures with cervical clearance on the supporting structures of unilateral distal extension removable partial dentures. <br />Materials and methods: Twelve male partially edentulous patients exhibiting lower Kennedy class II (lost second premolar and molar teeth on one side) opposed by completely edentulous maxilla were selected. Single unilateral implant was placed in the edentulous first molar area of the distal extension ridge. Patients were rehabilitated by Maxillary complete dentures and mandibular tooth-implant retained telescopic partial overdentures. Patients were randomly divided by using closed envelope into two equal groups; according to the design of telescopic crown. Group I; patients received cervically relieved telescopic crowns, (cervical clearance), and Group II; patients received telescopic crowns with no relief between primary and secondary copings, (precise fit). Measuring probing depth, and radiographic changes in marginal bone height of the abutments, and crestal bone height of the residual ridge, were evaluated at 3, 6, 9 and 12 months after denture insertion.<br />Results: Statistical analysis revealed a significant increase in the means of the measured abutments probing depth, change in alveolar bone height of the abutments, and crestal bone height of the residual ridge (mm) during the follow up time intervals in both group I (cervical clearance) and group II (precise fit). Abutments having telescopic crowns with precise fit showed significantly higher probing depth and change in alveolar bone height compared to those with cervical clearance. There was no statistically significant difference in the change in crestal bone height between the two studied groups at the end of the study period. <br />Conclusions: Telescopic retainers with cervical clearance are recommended for unilateral partial dentures compared to those with precise fit as they have a lowest destructive effect on the change in probing depth and height of the marginal bone of the abutments. However, the change in the crestal bone height was not significantly affected by the design of the telescopic retainers.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101EFFECT OF HYPERBARIC OXYGEN THERAPY ON THE OSSEOINTEGRATION AROUND IMPLANTS AFTER MANDIBULAR RECONSTRUCTION BY DESTRACTION OSTEOGENESIS4955057912510.21608/edj.2020.79125ENSahar KH.Abdel-BaryAssociate Professor of Removable Prosthodntics, Faculty of Dentistry, Misr University for Science and TechnologyUsama A.MEl DakroryLecturer of Oral and Maxillofacial Surgery Department, Faculty of Dentistry, Misr University for Science and TechnologyJournal Article20200325Increases in mandibular width by distraction osteogenesis have recently been shown to be an acceptable and stable treatment option for deficiencies, and also, in the oral rehabilitation, where one of the major problems is the alveolar bone loss, and adjacent soft tissues.<br />Aim: The aim of this study is to evaluate the influence of hyperbaric oxygen therapy (HBOT), on the osseointegration of implants retained partial mandibular overdenture after reconstruction of mandibular deficiency by distraction osteogenesis. <br />Methods: This study was conducted on eight male patients with a lack of the anterior mandibular jaw bone due to anterior marginal mandibulectomy, and partially edentulous maxillary arch (different classes), selected from the maxillofacial outpatient clinic, Faculty of Dentistry, Misr University for Science and Technology, (mean age 43 years, minimum 35 years and maximum 51 years). For all patient, distraction the insufficient alveolar ridge by using an Extraosseous Track Alveolar Distractor (KLS Martin, Germany), after consolidation period, patients received maxillary and mandibular conventional acrylic partial dentures prior to implant insertion. Then, each patient received two endoosseous implants in the mandibular interforaminal region, (following two stage surgical protocols), to retain partial mandibular overdentures. Patients were randomly divided by closed envelops, into two equal groups. Group I; Patients were received hyperbaric oxygen therapy (HBOT), on a protocol of five sequential sessions (study group), while Group II; Patients were received no hyperbaric oxygen therapy (HBOT), as a control group. Ball attachments were screwed to the implants, after four months of surgery. All patients received new mandibular removable partial overdentures were retained by two implants, and designed as Kennedy class IV partial overdentures, to fitted partial mandibular overdentures. Marginal bone height changes and bone density were assessed using cone beam computed tomography(CBCT); at time of prosthetic loading, then after six, and twelve months.<br />Results: Decrease in marginal bone height and increase in bone density through a follow-up period (one year) were observed in both groups , however; group I; that received HBOT revealed less marginal bone resorption and more increase in bone density than group II. <br />Conclusion: After mandibular reconstruction by distraction osteogenesis, hyperbaric oxygen therapy effective treatment, and improve osseointegration around implants retained partial ovedentures, as it associated with increased bone density and reduced marginal bone loss after one year follow up.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Impact of Preparation Depth and Length on Fracture Resistance of Anterior Teeth Restored by Endocrowns and Post Retained Crowns5075167912610.21608/edj.2020.79126ENShamsWaazLecturer of Fixed Prosthodontics, Faculty of Dentistry, Minia University, Minia, EgyptJournal Article20200325Objectives: To evaluate the effect of preparation depth (3mm deep endocrown, 6 mm deep endocrown and post retained crown) and different remaining coronal length (1mm & 2mm) of CAD/CAM fabricated restorations (zirconia reinforced lithium silicate) on fracture resistance of endodontically treated anterior teeth. <br />Materials & Methods: Twenty zirconia reinforced lithium silicate restorations, VITA Suprinity ceramic (VITA Zahnfabrik, Germany) were fabricated through CAD-CAM on a central incisor root. The specimens were randomly divided to divided into four Groups (n = 5 in each) Group I: CAD/CAM zirconia reinforced lithium silicate short endocrown (3mm depth) with 1mm remaining coronal length, Group II: CAD/CAM zirconia reinforced lithium silicate short endocrown (3mm depth) with 2mm remaining coronal length, Group III: CAD/CAM zirconia reinforced lithium silicate long endocrown (6mm depth) with 1mm remaining coronal length and Group IV: zirconia reinforced lithium silicate crown retained by glass fiber post (Glassix radiopaque, H Nordin, Chailly/Montyreux, Switzerland) and composite core (nano hybrid universal A3 shade Z250XT (3M ESOE Z250XT, Seefeld,Germany)with 1mm dentin collar (conventional treatment). Then, all the specimens subjected to thermocycling (Robota BILGE,Turkey) and fracture resistance test was performed by using a universal testing machine (Lloyd LRX, Lloyd Instruments, Fareham Hants, UK) at 45º angle to the long axis of the teeth. The data was statistically explored using one-way ANOVA and post-hoc Tukey tests (P value < 0.05)<br />Results: The highest mean fracture resistance value was obtained on group II (835.3±7.9 N). While, the lowest mean value of fracture resistance was obtained in group IV (286.8-295.4N). Furthermore, the fracture resistance mean value hadn’t statistically significant different between all tested groups. <br />Conclusions: Anterior endocrown monoblock restorations with short depth (3mm) and 1mm ferrule height can be used as an unusual to post retained crown restorations.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Effect of Different Surface Finishing Procedures on the Color and Translucency of two CAD/CAM Monolithic Glass Ceramics5175307912710.21608/edj.2020.79127ENAmiraEl SharkawyAssistant professor of Fixed Prosthodontics, ProsthodonticsDepartment, College of Dentistry, Misr University for Science and Technology. , EgyptMohammed MoustafaShalabyLecturers of Fixed Prosthodontics, Fixed prosthodontics department, Faculty of Dentistry, Minia University, Egypt.Journal Article20200325Purpose: The purpose of this study was to investigate the effects of different surface finishing procedures, storage solutions, and prophylactic polishing on the color and translucency parameters (TPs) of two machinable glass ceramics; lithium silicate glass-ceramic (Obsidian)and lithium disilicate reinforced glass-ceramic (IPS e-max CAD). <br />Materials and Methods: Obsidian and e-max milling blocks were sectioned with a low speed cutting machineunder water cooling into square specimens (10×10×1 mm3)(N=60). The specimens were divided into 3 groups (n=10 each) according to the received surface treatment; finishing and polishing, glaze, and staining and glaze in accordance with manufacturers’ instructions. Then, each group was further subdivided into 2 storage subgroups, coffee and distilled water as a control (n =5 for each subgroup). Color and translucency values were measured in CIELAB color space with spectrophotometer at the initial stage, and following 18 days, and after fine-grit prophylactic polishing paste application. Color changes (ΔE) and translucency (ΔTPs) were calculated and statistically analyzed using One-way ANOVA for comparing surface treatment followed by Tukey’s pair-wise if showed significant. Student t-test was used within material type to show effect of staining. Multifactorial analysis of variance ANOVA was performed to detect significance between variables (material type, surface treatment, immersion solution and re-polish).<br />Results: There was a statistically significant difference between the ΔE values of both immersion solutions as (p = water) for both ceramics tested. Obsidian and e-max, glaze procedure showed lower color change values than finishing and polishing and staining and glazing surface(p > 0.05) following coffee storage. It was found that re-polish decreased color change significantly for both tested ceramics. The translucency was affected according the monolithic CAD/CAM ceramic type. The translucency of the e-max was found to be higher than that of obsidian glass-ceramic. Colorant coffee solution decreased the translucency of both obsidian and e-max ceramics. According to the results of this study, mechanical polishing exhibited highest translucency than stained and glazed and glazed groups. The re-polishing procedure decreased translucency parameter non-significantly for both tested ceramics. <br />Conclusions: Within the limitations of this study, the following conclusions could be drawn: Staining drinks as coffee had a negative effect on the color stability and translucency of both obsidian and e-max glass ceramic materials tested. Glaze procedure led to more color stability with respect to finishing and polishing and stained and glaze for both ceramics after 18 days coffee storage. Polishing paste led to a decrease in color changes for both ceramics tested. The translucency was affected according the monolithic CAD/CAM ceramic type. The translucency of the e-max lithium disilicate glass-ceramic was found to be higher than that of obsidian lithium silicate glass ceramic after different finishing procedure, after coffee storage and after re-polish. Finished and polished groups presented the highest translucency than stained and glazed and glazed for both ceramics tested. Re-polish decreased translucency parameters non-significantly for both tested ceramics.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Weakening the bond strength of luting agents could be a goal in implant retained prosthetics5315407912810.21608/edj.2020.79128ENMostafa AAbdellatifAssociate Professor of Dental Materials Science, Biomaterials Department, Faculty of Oral and Dental Medicine, Future University in Egypt, FUE.Mohammed MoustafaShalabyLecturer of Fixed Prosthodontics, Fixed Prosthodontics Department, Faculty of Dentistry, Minia University, EgyptJournal Article20200325Aim of the study: The current study was conducted to provide a simple practical technique to relatively weaken the bond strength of E.max Press copings retained to zirconia implant abutment models. This technique should facilitate crown retrieval from onto implant abutments without affecting the integrity of the ceramic crowns, abutment or the implant’s integration, yet, the crown is still well retained during service.<br />Materials and methods: Twenty four zirconia implant abutment models were specially fabricated for the current study, to which 24 e.max press copings were cemented. According to the cementation technique, the samples were divided into four groups, 6 samples each. In Gp A, copings were cemented with a temporary resin luting cement without any surface treatment to the abutment models or the intaglio surfaces of the copings. In Gp B, abutments’ surfaces as well as intaglio surfaces of the copings were treated according to manufacturers’ instructions before cementation with permanent resin luting cement. In Gp C, abutments’ surfaces were coated with a single coat of fresh whole saliva before cementing copings with the permanent resin luting cement. In Gp D, same as in Gp C with replacement of saliva with single coat of glycerin. All assemblies were then subjected to aging through thermocycling for 5000 cycles.<br />All assemblies were then tested for retention of coping cemented to the zirconia implant abutment models and failure surfaces were then examined by stereomicroscope to detect the mode of failure.<br />Results: All samples in Gp A failed before any mechanical testing. Gp C reviled insignificant bond strength results compared to Gps B and D. However, Gp D showed significant reduction in bond strength compared to Gp B.<br />Conclusions: Glycerin coating of zirconia implant abutments before use of permanent resin luting cement would be a good technique to retain crown in place for longer time, yet still liable to easy retrieval.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Effect of deep marginal elevation on marginal adaptation and fracture resistance in endodontically treated teeth restored with endocrowns constructed by two different CAD/CAM ceramics: an in-vitro study5415567912910.21608/edj.2020.79129ENShams Waaz AmgadAliLecturer of Fixed Prosthodontics, Department of Fixed Prosthodontics, Faculty of Dentistry, Minia UniversityDalia Ali AhmedMoukarabLecturer of Endodontics, Department of Endodontics, Faculty of Dentistry, Minia UniversityJournal Article20200325Aim: To evaluate the effect of deep marginal elevation on the marginal adaptation and fracture resistance in endodontically treated teeth restored with endocrowns constructed by two CAD/CAM ceramics in an in-vitro model. <br />Material and methods: twenty four human, intact freshly extracted mandibular first molars were endodontically treated and mounted in an upright position in a standard plastic ring filled with acrylic resin 4mm apical to the CEJ. A standard endocrowns preparation was performed with a butt- joint occlusal margin for all specimens and a proximal box preparation was done on the mesial surfaces. The specimens were then equally divided in to two groups (n=12) according to the material used in construction group (M) using IPS e.max CAD ceramic blocks and group (V) using Vita Enamic ceramic blocks; then further divided in to two subgroups (n=6) according to the application of a mesial marginal elevation or not into (ME, VE) with marginal elevation and groups (MN, VN) without marginal elevation. All endocrowns were cemented to the corresponding preparation using dual cured self- adhesive resin cement (RelyX, Unicem). All specimens were thermally aged with 10000 cycle in water bath between 5˚C- 55˚C. The marginal adaptation was evaluated using stereomicroscope (40 ×) at 5 predetermined points on the mesial margin for each specimen and mean gap measurement was calculated. All specimens were then subjected to fracture resistance test via universal testing machine. The collected data was recorded, tabulated and transferred for statistical analysis. <br />Results: Vita Enamic with deep marginal elevation (VE) recorded the lowest marginal gap measurements at (69.3 µm)which is significantly lower than all tested subgroups (P < 0.001), while IPS e.max CAD with deep marginal elevation (ME) subgroup showed significantly higher fracture resistance (1478.2N) than all tested subgroups (P< 0.001). <br />Conclusion: Deep marginal elevation enhances both marginal adaptation and fracture resistance of IPS e.max CAD and Vita Enamic. IPS e.max CAD has higher fracture resistance while Vita Enamic has better marginal adaptation.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101The Effect of Two Implant-Abutment Connections on Maximum Bite Force, Prosthetic Maintenance and Peri-Implant Sulcular Fluid in Mandibular Implant Supported Telescopic Overdenture: A Split-mouth study5575707913010.21608/edj.2020.79130ENIman A.El-AsfahaniLecturer of Removable Prosthodontics, Faculty of Dentistry, Minia UniversityAmr M.IsmailAssociate Professor of Removable Prosthodontics, Faculty of Dentistry, Minia UniversityJournal Article20200325Purpose: The aim of this study was to evaluate and compare two different implant-abutment connections (conical and trilobe connection) in mandibular implant supported telescopic overdenture. The parameters of evaluation were the maximum bite force, prosthetic maintenance and peri-implant sulcular fluid. <br />Materials and method: Twelve completely edentulous patients received new complete dentures. After 3 months of adaption to the new denture, 24 implants (12 implants with conical implant-abutment connection (group A) and 12 implants with trilobe implant-abutment connection (group B). The Insertion of each type of implant was randomly assigned between the two contralateral sides intraorally for each patient using a statistical software. Each patient was treated according to split mouth design. The implants were inserted in the canine region of the mandible using two-stage surgical technique and conventional loading protocol. After 3 months, implants were exposed and a telescopic overdenture was constructed. The maximum bite force, prosthetic maintenance and peri-implant sulcular fluid for each group of implants were evaluated at loading time, after 6 and 12 months.<br />Results: There was no statistically significant difference in maximum bite force between group A and B the at loading time, but there was a statistically significant difference at 6 and 12 months follow up visits. The prosthetic maintenance events in group A were 1 event compared to 5 events in group B. There was no statistically significant difference between group A and B in the peri-implant sulcular fluid at loading time, 6 and 12 months follow up visits. <br />Conclusion: Within the limitations of this study, it can be concluded that the conical implant- abutment connection is associated with increased maximum bite force compared to the trilobe Implant-abutment connection. Conical implant-abutment connection can provide a stable implant system with fewer prosthetic complications and maintenance services compared to trilobe implant -abutment connection.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Effect of CAD/CAM versus conventional anterior repositioning splints on the management of temporomandibular joint disc displacement with reduction: A randomized controlled clinical trial5715857913110.21608/edj.2020.79131ENIman A.El-AsfahaniLecturer of Removable Prosthodontics, Faculty of Dentistry, Minia UniversitySahar A.KortamLecturer of Removable Prosthodontics, Faculty of Dentistry, Beni-Seuf UniversityJournal Article20200325Purpose: The aim of the current study was to investigate the effect of CAD/CAM versus conventional anterior repositioning splints (ARS) on the management of temporomandibular joint disc displacement with reduction. <br />Materials and methods: Twenty patients (15 females and 5males) diagnosed (clinically and by magnetic resonance imaging (MRI)) with disc displacement with reduction (DDWR) were selected from the outpatient clinic of oral and maxillofacial surgery department, Faculty of Dentistry, Beni-Suef University. Patients were randomly divided into two groups; Group I patients received ARS constructed following the conventional technique. Group I patients had 8 normal (control) and 12 DDwR joints as scanned by MRI. Group II patients received ARS constructed by CAD\CAM technique. Group II patients had 6 normal(control) and 14 DDwR joints as scanned by MRI. Subjective symptoms were evaluated using temporomandibular disorder (TMD) questionnaire before treatment (baseline), 1-, 3- and 6-months post- insertion. Moreover, MRI measurements of the disc-condyle angle and the disc/condyle positions were performed for normal (control) and DDwR joints in group I and group II. There measurements were done before treatment, immediately at the time of splint insertion and finally after 6 months post-insertion. <br />Results There was no statistically significant difference between the scores of TMD questionnaire items between group I and group II at baseline and different follow up visits. Likewise, there was no statistically significant difference in disc-condyle angle and disc/condyle positions (MRI measurements) between DDwR joints in group I (conventional ARS) and group II (CAD/CAM ARS) at pretreatment, immediately at the time of splint insertion and after 6 months post-insertion. <br />Conclusion Within the limitations of this study, there was no significant difference between the effect of CAD/CAM versus conventional ARS on the management of DDwR. Hence, the CAD/CAM ARS can provide a good substitute to the conventional ARS in treatment of DDwR eliminating human errors and saving time. Moreover, the superior effect of ARS in the management of DDwR could be related mainly to the design of the splint rather than the method involved in the construction of the splint.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Evaluation of antimicrobial activity of manually agitate (nano- chitosan and nano- propolis) against Enterococcus faecalis in comparison with sodium hypochlorite: an in-vitro study5875967913210.21608/edj.2020.79132ENDalia Ali AhmedMoukarabLecturer of Endodontics, Department of Endodontics, Faculty of Dentistry, Minia UniversityJournal Article20200325Aim: The purpose of this study was to evaluate in an in-vitro model the antibacterial efficacy of manually agitated nano- chitosan and nano-propolis as root canal irrigation protocols in comparison to manually agitated sodium hypochlorite against Enterococcus Faecalis.<br />Material and Methods: The root canals of 50 single rooted human premolars were flattened to a standard length of 18mm cleaned and shaped to a size F5 Protaper, apices closed with composite, fixed into an Eppendorf vial with silicon impression material, autoclaved, and randomly assigned to the test groups (n=10) . Negative control was autoclaved and microbial analyzed. The other 40 specimens were contaminated with freshly prepared suspension of E. Faecalis and incubated for 4 weeks and equally divided into 4 groups positive control group (n=10) was not subjected to any further treatments, group A final irrigation with 5.25% NaOCl, group B final irrigation with nano-chitosan and group C final irrigation with nano- propolis ; all irrigation protocols were combined with manual agitation with well fitted gutta perch cone for 2 minutes under a laminar flow hood. Microbial samples were collected from all the root specimens and colony forming units were counted and transformed into log CFU. The collected data were statistically analyzed. <br />Results: There was no statistical significant difference in log CFU count between group A (treated with NaOCl) and group B, C (treated with CNP and PNP) while groups A, B, C showed statistically significant difference from positive control group with (p> 0.05).<br />Conclusion: With in the limitations of the present study it can be concluded that all irrigation protocols had efficient antibacterial effect against E. faecalis. <br />Manually agitated (CNP or PNP) can be considered as a more safe, efficient, and simple alternative instead of sodium hypochlorite against E. faecalis.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Relationship between Shear Bond Strength and Fluoride Content of Fluoridated Teeth as Stated by Scanning Electron Microscopy and X-Ray Fluorescence Analysis5976097913310.21608/edj.2020.79133ENSamyEl-SaftyLecturer, Department of Dental Biomaterials, Faculty of Dentistry, Tanta UniversityTasneem AAlmohamadyOrthodontist, El-Santa Central Hospital, El-Santa, Gharbia, EgyptJournal Article20200325Objectives: To study the effect of fluoride treatment on shear bond strength (SBS) of orthodontic brackets and to investigate the relationship between SBS and fluoride content of fluoridated teeth by means of scanning electron microscopy (SEM) and X-ray fluorescence (XRF) analysis.<br />Materials and methods: A total of one hundred sound maxillary premolars were thoroughly cleaned and randomly assigned to 5 groups (n=20): control group without fluoride treatment and four groups fluoridated with Profluorid® Varnish 5% NaF (VOCO GmbH. Cuxhaven, Germany) and stored in artificial saliva for varied periods: 1 day, 3 days, 5 days and 7 days. After completing the predetermined storage time, specimens of each group were subdivided into two subgroups (n=10); ten specimens were used for SBS testing and the other ten specimens were submitted to XRF analysis to study their fluoride content. An etchant (phosphoric acid 37%) and a resin adhesive system Transbond XT (TXT) (3M ESPE, St. Paul, Minn) were used to bond the ceramic brackets (Perfect Clear, Orthodontic Sapphire Ceramic Brackets, HUBIT Co., Ltd. South Korea) to the teeth surfaces. Debonding was carried out in a universal testing machine (Lloyd, Type 500, Lloyd Instrument, England) at a cross-head speed of 1 mm/min. After debonding, a stereomicroscope (Olympus SZ 60, Japan) was used to determine the type of fracture of each specimen and scores of adhesive remnant index (ARI) were given. SEM investigation was conducted on representative specimens of debonded tooth surfaces of all groups in a scanning electron microscope (Jeol, JSM-5200LV scanning microscope, Japan). XRF analysis was carried out using AXIOS, WD-XRF Sequential Spectrometer (Malvern Panalytical, 2005, United Kingdom). Crowns of specimens of each subgroup were cut, ground and pressed by the aid of binding wax to form disc-shaped specimens (35 mm in diameter × 3 mm in thickness) that were submitted to the XRF analysis. One-way ANOVA, Tukey test and chi-square test were used to analyze the data. Significance level was established at (p ≤ 0.05). <br />Results: statistically significant differences were found between studied groups in both SBS values and ARI scores. SEM examination showed that fluoride layer acted as a barrier hindering proper etching of tooth surface that resulted in poorer bonding compared to control group. Longer storage, however, caused fluoride layer to be washed away giving better bonding. XRF analysis revealed greater fluoride content of groups with shorter storage time compared to those with longer storage. Linear regression analysis revealed a strong positive correlation (R2 = 0.936) between SBS and storage time and a strong negative correlation (R2 = 0.959) between SBS and fluoride content of fluoridated groups.<br />Conclusions: As confirmed by SEM and XRF analysis, fluoride reduced SBS of orthodontic brackets in the first few days of fluoride treatment. As fluoride dissolved in artificial saliva after a period of time, SBS recovered to normal values. <br />Clinical significance: For patients who are in need to orthodontic treatment, if fluoride treatment is mandatory, bonding of orthodontic brackets should be postponed seven days after treatment to get adequate bonding to the tooth structure.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Bar versus Locator attachments for maxillary implant overdentures opposed by implant supported mandibular overdentures. Clinical and radiographic evaluation6116227913410.21608/edj.2020.79134ENAhmad FathallaShawkyAssociate Professor of Removable Prosthodontics, Faculty of Dentistry Beni- Suef University0000-0002-6000-5976Ahmed Samir AhmedKhair AllahAssociate Professor of Removable Prosthodontics, Faculty of Dentistry Mansoura UniversityJournal Article20200325Purpose: The aim of this short-term clinical trial was to evaluate clinical and radiographic outcomes of Bar and Locator attachments used to retain maxillary implant overdentures opposed by implant supported mandibular overdentures. <br />Material and methods: Ten patients wearing conventional maxillary denture and implant supported mandibular overdentures received 4 implants in the maxillary arch using 2 stage surgical approach. Six months later maxillary overdentures were connected to the implants with locator (group 1) or bar (group 2) attachments. Plaque index, bleeding index, probing depth, implant stability, and marginal bone loss (using Cone beam computerized tomography) were evaluated at time of overdenture delivery, 6 months and 12 months later. <br />Results: Plaque and gingival indices increased significantly with time in bar group only. Bar overdentures recorded significant higher plaque and gingival scores than locator overdentures. No significant difference in pocket depth and implant stability was noted between time intervals or groups. Total marginal bone loss for locator group was significantly higher than bar group after 6 and 12 months. For both groups, marginal bone loss around canine implants was significantly higher than bone loss around premolar implants<br />Conclusion: Within the limits of this study, it could be concluded that both locator and bar retained maxillary overdentures are successful treatment options for patients complaining from instability of maxillary dentures opposed by implant retained mandibular denture. However, locator attachments are advantageous in terms of peri-implant soft tissue health and bar attachments are advantageous regarding peri-implant alveolar bone preservation.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Assessment of an Ergonomics Interventional Educational Program on Knowledge, Attitude, Practice and Behavior among a Group of Egyptian Dental Students6236327913510.21608/edj.2020.79135ENEmanAlaaLecturer, Pediatric Dentistry and Dental Public Health Department, Faculty of Oral and Dental Medicine, Future
University in Egypt.Sara H.YounisLecturer, Conservative Dentistry Department, Faculty of Oral and Dental Medicine, Future University in Egypt.Journal Article20200326Oral and Dental Medicine is a profession where clinically, operational skill is restricted to an area covering only a few tens of millimeters (the mouth) and requires repeated, precise force application while delivering oral health. Ergonomic is the science dealing with people and their working environment, but evaluation of ergonomics’ awareness is minimal among dentists. <br />Aim: To assess the effect of an ergonomics interventional educational program on knowledge, attitude, practice and behavior among a group of Egyptian dental students. <br />Subjects and Methods: In an interventional study, 40 right-handed dental students aged 20–25 years were educated and assessed on ergonomics in dentistry. The participants were requested to fill out a questionnaire about ergonomics before and after the interventional educational program. <br />Statistical analysis: Data were explored for normality using Kolmogorov-Smirnov and Shapiro-Wilk tests, data showed non-parametric (not-normal) distribution. Mann-Whitney test was used to compare between two groups in non-related samples. Wilcoxon test was used to compare between two groups in related samples. Spearman test was used to test correlation between variables. <br />Results: There was a statistically significant difference between (Before) and (After) groups where (p<0.001) regarding each of knowledge, attitude and practice in both females and males. Conclusions: The ergonomic educational program was effective in the promotion of knowledge, attitude and practice of dental students in relation to working body posture.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Surface Topography and Chemical Characteristics of Rotary Ni Ti Files of different manufacturing techniques after Multiple Use6336437913610.21608/edj.2020.79136END.MAbdAllahLecturer in Endodntic Department, Faculty of Dentistry, Suez Canal UniversityE.MElddamonyLecturer in Dental Materials Department, Faculty of Dentistry, Suez Canal UniversityR.AAbdelgawadLecturer in Dental Materials Department, Faculty of Dentistry, Suez Canal UniversityJournal Article20200326Background: This study designed to evaluate and compare surface physical and chemical characteristics of recently introduced rotary NiTi files Neolix (Neolix, Châtres-la-Forêt, France), One Curve (Micro mega, France) and AF™ Blue S ONE File System (Fanta, USA) before and after 1st and 3rd use. <br />Materials and Methods: In this study thirty brand-new endodontic files having tip size 25/0.6 of the following systems were used: Neolix (Neolix, Châtres-la-Forêt, France), One Curve (Micro mega, France) and AF™ Blue S ONE One-File System (Fanta, USA). These files were equally divided into three groups (n=10). Ninety simulated curved canals (Endo Training Block-L; Dentsply Maillefer, Ballaigues, Switzerland) with curvature of 45º±10º, with 0.02taper, 0.15 mm apical diameter, and 16 mm length were used. File`s surfaces examined by Environmental Scanning Electron Microscope ESEM (FEI Quanta 250 FEG, Berlin, Germany) at 500X magnification before use. Cutting blade (active part) images been processed and their micrographs were analyzed at the tip, 2 and 4 mm short of its cutting tip. The Nickel (Ni) and Titanium (Ti) average contents (wt %) on the instrument`s surface were also analyzed before their use, using an Energy Dispersive Spectrometer Device (EDAX - AMETEK, Inc., Mahwah, NJ, USA). All instruments prepared using electric motor (Motor X-Smart Plus, Dentsply/Maillefer), following manufacturer`s instructions for each system. Each used file prepared three simulated canals, after each canal instrumentation, each file was removed for cleaning its flutes gently with sterile gauze, and for canal irrigation using with 2 mL/ 2.5% NaOCl irrigating solution. After the first and third instrumentation performed; files were cleaned, dried, stored and sent to SEM equipment for post-instrumentation files surface’s topography analysis and chemical composition of the NiTi content (wt %) according to the previously described pre-instrumentation analysis protocol. SEM micrographs recorded on a CD-ROM and projected for three blinded examiners’. They were given a spreadsheet including the instrument data (number, the location to be evaluated; tip, 0-2mm or 2-4mm from the tip) and the side of the instrument (detail facing up or down), and the criteria of defects and deformation assessment namely (irregular edges, grooves, micro-cavities and burrs).Data were recorded and statistically analyzed.<br />Results: Analysis of surface defects (SEM) showed that; all file systems have pre-instrumentation surface defects which increased after use. Neolix file had highest significant difference in all detected surface defects with One Curve file, with AF™ Blue S ONE file in burs and micro-cavities at file`s Tip and 0-2mm, in all examination intervals(p<0.05). One Curve file showed the least surface defects with significant difference with AF™ Blue S ONE file in edges mean values at file`s Tip at all examination intervals. EDS chemical analysis of Ni and Ti % revealed; decrease in Ni, Ti weight % after first and third uses. Decrease in Ni% was more than Ti%. <br />Conclusion: surface defects of the studied instruments were recorded before use, continuous use promoted their increase. Chemical change results revealed significant changes in Ni and Ti content on instruments surface after reuse led to that may affect their performance.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Time-Dependent Effect of Different Intracanal Medicaments on Dentin Microhardness and Dislocation Resistance of MTA Used During Regenerative Endodontic Treatment6456587913710.21608/edj.2020.79137ENM.RHamdyLecturer in Endodntic Department, Faculty of Dentistry, Suez Canal UniversityE.MElddamonyLecturer in Dental Materials Department, Faculty of Dentistry, Suez Canal UniversityR.AAbdelgawadLecturer in Endodntic Department, Faculty of Dentistry, Suez Canal UniversityJournal Article20200326Objectives: This study was designed to measure and compare dentin microhardness and MTA (ProRoot, Dentsply Tulsa Dental, Tulsa, OK) dislocation resistance (DR) used in regenerative endodontic treatment (RET) after application of three different intracanal medication(ICM) for 2,4 and 12 weeks’ time intervals. <br />Material and methods: One-hundred sixty eight human maxillary central incisors were selected for the study. Teeth were cut apically 12 mm below and coronally 2 mm above the cemento-enamel junction. Canals were instrumented up to instrument F5 (ProTaper Universal, Dentsply Maillefer, Ballaigues, Switzerland), then Peeso drills (Mani, Tochigi, Japan) were used from No. 1 up to No. 6 , passing 1 mm beyond the apical foramen to obtain larger root canals. Between every 2 consecutive instruments 2 mL of 2.5% sodium hypochlorite (NaOCl) used for canals irrigation , final flush using 5 mL of 2.5% NaOCl and 5 mL of 17% ethylene-diamine-tetra-acetic acid (EDTA, Sigma) followed by 10 mL of distilled water. Samples were randomly divided according to the type of the ICM used inside the canal into 4 equal groups (n = 42); Group 1: Double antibiotic past(DAP) paste: 1:1 mixture of ciprofloxacin (Cipro 500 mg, Schering Plough, Kenilworth, NJ, USA) and metronidazole (Flagyl 500 mg, Sanofi-Aventis, Tours, France), Group 2: Bioactive glass powders (BAG S53P4) of 60 mol% SiO2, 12 mol% P2O5 and 28 mol% CaO composition were prepared through sol gel processing route, all reagents were purchased from Sigma-Aldrich(Dorset, UK). Group 3: Non-setting Calcium hydroxide (CH) (Merk, Germany) was used, and finally, Group 4(Control): where no ICM was applied. Samples were kept in saline solution for either 2, 4, and 12 weeks, randomly selected samples from each group n=14 at each interval where intracanal medication removed, half of them n=7 were subjected to dentin Vickers microhardness test, in remaining half n=7 MTA (ProRoot, Dentsply Tulsa Dental, Tulsa, OK) placed 4 mm deep into the coronal third of the roots having a 4 mm-long chamber, samples were stored for a week at 37 °C at 100 % humidity to allow the complete setting of MTA, then push-out test was used to measure the dislocation resistance DR of MTA. Collected data were analyzed using a two-way ANOVA followed by Bonferroni’s post-hoc test was used for pair-wise comparisons (P ≤ 0.05). <br />Results: showed that both DAP, CH groups of intracanal medication and time interval had a significant decreasing effect on dentine microhardness and MTA dislocation resistance the DR of MTA (P-value <0.001). While, BAG group`s results revealed significant increase in dentine microhardness and MTA dislocation resistance (P-value <0.001). The time factor displayed a significant effect on dentin microhardness and the DR of MTA (P-value <0.001).<br />Conclusion: Regarding situations in this study, intracanal medications type and duration of application used in root canals disinfection through RET must be carefully chosen to avoid negative effect on dentin microhardness or DR of MTA jeopardizing the success of the treatment. BAG (S53P4) showed promising results, further studies needed to complete investigations about it as intracanal medication in RET.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101All on 4 Versus All on 6 implant concepts for rehabilitation of edentulous maxilla. Short term randomized clinical and radiographic study6596707913810.21608/edj.2020.79138ENShahinaz Sayed MohamedHassanLecturer, Department of Removable Prosthodontics, Faculty of Dentistry, Beni-Suef University, Egypt.Amr Abd El Bary MahdyEmarahLecturer, Department of Removable Prosthodontics, Faculty of Dentistry, Fayoum University, Egypt.Journal Article20200326Purpose: The aim of the present study was to evaluate clinical and radiological outcomes of “All on 4” Versus “All on 6” implant concepts for rehabilitation of edentulous maxilla. <br />Materials and methods: 10 patients with complete maxillary edentulism and distal extension mandibular ridges who had resorption in the posterior aspects of the maxillary ridge were randomly assigned into 2 groups: Group 1 included 5 patients who received All on four maxillary prosthesis, and group 2 included 5 patients who received All on six maxillary prosthesis. Four (group 1) or six (group 2) implants were inserted between the maxillary sinuses and immediately loaded by provisional acrylic dentures. Definite screw retained porcelain fused to metal fixed prosthesis were inserted after 6 months. Plaque index, gingival index, probing depth, implant stability, and peri-implant bone loss were measured for both groups at base line (after insertion), 6 months and 12 months after insertion. <br />Results: The survival rate was 85% and 100% for group 1 and group 2 respectively. Plaque and gingival scores significantly increased with time in group 1 only. At 6 and 12 months, group 1 showed significant higher plaque and gingival scores than group 2. Pocket depth and implant stability increased significantly with time in both groups. Group 1 showed significant higher pocket depth and reduced implant stability than group 2 at all observations. Bone resorption significantly increased after 12 months compared to 6 months in both groups. Group 1 recorded significant higher bone loss than group 2 after 6 and 12 months of prosthesis delivery. <br />Conclusion: Within the limitations of this study, it could be concluded that All on 6 implant concept is recommended for restoration of atrophied maxilla compared to All on 4 implant concept as it was associated with improved clinical and radiographic parameters after one year.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Implant supported mandibular overdentures with Locator attachments in patients with resorbed mandibular ridges. A cross over study of patient satisfaction and oral health related quality of life6716817913910.21608/edj.2020.79139ENShahinaz Sayed MohamedHassanLecturer, Department of Removable Prosthodontics, Faculty of Dentistry, Beni-Suef University, Egypt.Mohamad Hossam El-DinHelmyLecturer, Department of Removable Prosthodontics, Faculty of Dentistry, Assiut University, Assiut , Egypt.Journal Article20200326Purpose: The aim of this cross over study was evaluation of patient satisfaction and oral health related quality of life (OHRQoL) for implant supported mandibular overdentures with locator attachments in patients with resorbed ridges <br />Materials and methods: Six participants (3 males and 3 females) with total maxillary and mandibular edentulism who complained from lack of retention of old mandibular dentures due to ridge resorption received new conventional dentures. After 3 months adaptation period, 4 implants were inserted between the 2 mental foramina of the mandible using one stage non submerged delayed loading approach. After 3 months of integration period, dentures were connected to the implants with Locator attachments. Patient satisfaction was measured using patient satisfaction questionnaires and oral health related quality of life was measured using oral health impact profile (OHIP-14). Measurements were made after 3 months of using conventional dentures (control group) and implant overdentures (study group). <br />Results: Regarding VAS questionnaires, test group showed significant higher general satisfaction, satisfaction compared to natural teeth, satisfaction with retention, stability, occlusion, speech, mastication, prosthesis is a part of patient, and lack of embarrassment compared to control group. Regarding OHIP-14, test group showed significant less pain and more comfort on eating, less self-consciousness, and less sensation of tense, more satisfaction with food and less interruption of meal, more ability to relax and less embarrassing, less irritation with other and more satisfaction with life generally and less difficulty in function well than control group <br />Conclusion: Implant supported mandibular overdentures with locator attachments are recommended for patients with atrophied mandibular ridges as they significantly improve patient satisfaction and quality of life compared to conventional dentures.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101CYCLIC FATIGUE RESISTANCE OF NEWLY INTRODUCED SURFACE AND THERMAL TREATED NICKEL-TITANIUM ROTARY FILES6836947914010.21608/edj.2020.79140ENHajer M.Abd ElHamidLecturer of Endodontic, Endodontic Department – MTI University – Cairo -EgyptJournal Article20200326Objectives The main objective of the present study invitro was to evaluate the cyclic fatigue resistance and metallurgic properties of newly thermal treated (CM wire) rotary Ni-Ti files with different surface treatments.<br />Materials and Methods: A total of one hundred and twenty rotary files were used from three different rotary systems with the same thermomechanical treatment – controlled memory wire (CM Wire) and different surface treatment technique using rotation motion. Groups were set as Group 1: M3 Pro Gold (United Dental, Shanghai, China) (CM Wire) size (25/0.04), Group 2: AF F One Blue (Fanta Dental Material Co., Shanghai, China) [controlled memory wire (CM Wire)] size (25/0.04) and Group 3: Hyflex EDM (25/ 0.04). These files were tested for cyclic fatigue resistance using a custom-made static cyclic fatigue testing apparatus with various angles and radius (angle 60 radius 2.5mm and 5mm radius and angle 90 radius 2.5mm and 5mm). Each rotary file was coated with EDTA after its attachment in handpiece supported in stainless steel cylinder apparatus. M3 Pro Gold rotary files, AF F one blue and Hyflex EDM rotary files were rotated at 500rpm 2.5N/cm torque according to manufacture instructions. Digital watch was used to record the time taken until file fracture in seconds and the (NCF) number of cycles till fracture were calculated. Scanning electron microscope SEM image of the fractured surface were taken. Statistical analysis was performed using one-way analysis of variance and Tukey’s test at the 95% confidence level (P = 0.05). <br />Results: After comparing the cyclic fatigue resistance of AF F One Blue and M3 Pro Gold by recording time till the file fracture was ranged between 670s to 1180s in all groups at angle 60 degree with different radius and 10s to 815s in all groups at angle 90 degree with different radius. There were no significant differences between the M3 Pro Gold and AF F One Blue rotary files at angle 60 degree and 90 degree in both radius 2.5mm and 5mm ( P> 0.05), while there were significant differences between the Hyflex EDM and M3 Pro Gold and AF F One Blue rotary files at angle 60 degree, radius 2.5mm ( P> 0.05). Hyflex EDM have the highly significant differences M3 Pro Gold and AF F One Blue rotary files at angle 90 degree, radius 2.5mm (P < 0.001). <br />Conclusions: All new thermomechanical treatment technique - controlled memory CM-Wire rotary systems represented great performance and remarkable enhancement in cyclic fatigue resistance but the Hyflex EDM rotary files had the highest cyclic fatigue resistance among the M3 Pro Gold and AF F one Blue rotary files. Also surface treatment of the rotary files enhancing the cyclic fatigue resistance by decreases surface micro cracks and the tendency to fracture.The Egyptian Dental Association (EDA)Egyptian Dental Journal0070-948466Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics)20200101Marginal Chipping Of Three Different CAD/CAM Ceramic Veneering Materials As Influenced By Machinability6957077914110.21608/edj.2020.79141ENCarlHanyAssociate Professor, Fixed Prosthodontics Department, Faculty of Dentistry, Cairo UniversityMahaTymourAssociate Professor, Fixed Prosthodontics Department, Faculty of Dentistry, Cairo UniversityJournal Article20200326Statement of the problem: The curiosity of many prosthodontists was attracted towards CAD/CAM technology combined with the newly specifically designed ceramic materials to achieve superb esthetic restorations for their patients. The new ceramic materials with their different mechanical properties might have an impact on their machinability particularly for producing thin esthetic restorations.<br />Purpose: The purpose of this investigation was to evaluate the marginal quality of three different ceramic veneers: Leucite reinforced, hybrid and lithium di-silicate in terms of edge chipping and chipping factor using different machining protocols.<br />Materials and methods: In order to achieve the purpose of this study, a maxillary central incisor of a Typodont was prepared for a feather edge veneer preparation to receive forty five ceramic veneers that were milled from three different materials using the Cerec CAD/CAM system. The three tested materials were leucite-reinforced glass ceramic (IPS Empress CAD), hybrid ceramic (Vita Enamic), and lithium di-silicate glass ceramic (IPS e.max CAD). The forty five veneers were classified into three groups according to the type of the material fifteen each, that were further divided into three subgroups of five specimens each according to the three tested machining speeds: normal, fast, and two-step. A digital camera was used for taking top images for the tested veneer margins that were imported into image analysis software to measure the peripheral veneer circumference (P). A stereomicroscope was used to measure the amount of marginal chipping of each veneer in microns (L). The chipping factor (CF) was calculated using the following equation: CF= L/P x 100, where (L) is the amount of marginal chipping and (P) is the marginal circumference of each veneer. The data of the chipping factor of each veneer margins were recorded and tabulated to be statistically analyzed in order to detect the influence of either the ceramic material or the machining protocol on the quality of the veneer margins in terms of edge chipping.<br />Results: Effect of ceramic type regardless of machining protocol: The statistical analysis of the obtained data revealed that e.max CAD (LD) showed the statistically significant highest mean chipping factor value (7.25 ± 2.56) followed by IPS Empress CAD (LR) (4.01 ± 0.83), and the least mean value was obtained with Vita Enamic (HC) (2.83 ± 1.56). Effect of machining protocol regardless of ceramic type: there was a statistically significant difference between the three milling techniques, where fast milling showed the highest mean chipping factor value (6.30±2.97), followed by normal milling (4.89±2.22) where the least chipping factor mean value (2.90±1.60) was obtained with the two-step milling.<br />Conclusions:<br />The edge quality of thin ceramic CAD/CAM restorations proved to be material dependent.<br />The machinability for producing thin CAD/CAM ceramic restorations influenced significantly their marginal quality.<br />The prosthodontist should be aware and knowledgeable about the mechanical properties of the recent CAD/CAM ceramic materials in order to choose the optimum one with the convenient milling protocol during the treatment planning to get the best clinical performance.