Color Assessment of Screw-Retained Implant Prostheses Access Hole Fillings: An In-Vitro Study

Objectives: This study aimed to investigate the aesthetic aspect of screw-retained restorations by examining three different types of filling materials used for the access cavity, highlighting the significance of aesthetics in implant restorations. Materials and Methods: In this laboratory investigation, simulation samples of screw-retained restorations were filled with flowable composite resin (group F), opaque and flowable composite resin (group O) and porcelain plug (group P) at baseline (T0). The samples were subjected to thermocycling twice (T1 and T3), undergoing 1000 cycles in coffee, orange juice, and distilled water, followed by washing performed after each thermocycling (T2 and T4). Colorimetric analysis and surface roughness measurements were conducted, and the data were statistically analyzed using. two-way analysis of variance (ANOVA), ,Tukey post hoc, two-way analysis of covariance (ANCOVA), and paired-t test. P<0.05 was considered significant. Results: The type of filling material had a significant effect on the color difference observed between the restoration and filling materials (P<0.05). Notably, samples from group P exhibited a more pronounced color difference at T4, despite showing a lower color difference at T0, when compared to group O. Conclusion: The use of porcelain plugs did not provide a notable advantage over the combination of flowable and opaque composite resins, particularly given the difficulties in fabricating and positioning porcelain plugs within the access cavity. Therefore, it is recommended to utilize flowable composite resins in conjunction with an opaque composite resin layer beneath, to effectively conceal any dark shades from the underlying metal.