DIGITAL SPECTROPHOTOMETER EVALUATION OF THE INFLUENCE OF SCREW COLOR AND ACCESS HOLE FILL ON THE COLOR OF SCREW- RETAINED IMPLANT CROWNS

Statement of problem: Although screw-retained implant crowns are commonly preferred by clinicians, there remain a limited number of studies on how color affected by screw color and access hole fill.
 
purpose: The purpose of this study was to  determine the influence of  screw color, opaque shade and composite thickness on the color of screw-retained implant crowns with use of digital spectrophotometer.
 
materials and methods: eighty specimens were divided into two groups ,gray group (pure titanium) and golden-colored group (anodized titanium) which used as two backgrounds. Composite discs with 1mm, 2mm,0.5mm opaque+0.5mm composite and 0.5mm opaque+1.5mm composite were fabricated. Titanium specimens and composite discs were placed into a collective mold in various tested groups for color measurements.
 
reSultS: Quantitative in concern to clinical color matching tolerance, It was found that, group 4A and 4B recorded the lowest ∆E as they could not detected by human eyes. Quantative color matching evaluation showed, no significant differences between gray and golden colored titanium(background), (P >0.05) while golden colored titanium gave higher ∆E than grey titanium group. For grey titanium; it was found that Group (4A) was the lowest ∆E value (1.20±0.4), followed by Group(2A) (4.00±1.3∆E), then Group (3A) (5.55±1.8 ∆E)while Group (1A) was the highest (7.6±2.53∆E) The difference in color change was significantly where (P= 0.001<0.05).\ For golden colored titanium; it was found that Group(4B) recorded the lowest ∆E value (1.15±0.38) followed by Group (2B)(3.65±1.26∆E) then Group (3B) (4.15±1.3∆E) while Group (1B) was the highest (5.55±01.8∆E). The difference in color change was significantly where (P= 0.0001<0.05).
 
conclusion: composite thickness and opaque shade composite affected ∆E values (p<0.05). while, the color of the background did not affect ∆E values (p>0.05) of the color of final restoration.
 
clinical implications: Screw color and access hole fill play an important role on the color of screw-retained implant crowns. In present study, regardless the implant color, the use of 0.5mm opaque composite covered by 1.5 mm composite resin affected the color of final restoration significantly.