Objectives: the aim of this randomized-controlled clinical trial was to compare the objective and subjective esthetic outcomes of two types of screwed-retained single-implant crowns.
Materials and methods: participants were randomly assigned to the test (all-ceramic) and control [porcelain-fused-to-ceramic (PFM)] groups and were seen under investigation at baseline (B), crown insertion (CI), 1-year follow-up (1Y), and 2-year follow-up (2Y). Objective parameters were assessed by an intra-oral digital photograph (1:1 ratio), a study cast, a standardized radiograph, periodontal/peri-implant measurements, and questionnaires were obtained for the subjective parameters. In addition, pink esthetic score (PES) and white esthetic score (WES) were calculated for both groups. For the subjective evaluation, a visual analogue scale (VAS) questionnaire was used to assess the level of patient satisfaction regarding the esthetic outcome. Then, nine expert clinicians visually inspected and assessed subjective evaluation at the professional level. Statistical analysis was used to compare between groups and investigational appointments.
Results: twenty patients were included in the study, 10 allocated to the all-ceramic group and 10 to the PFM group. No statistically significant differences were observed for the objective measurements comparing the test and control groups. Minor chipping of the ceramic veneering material was observed in the two patients of control group. The mean difference for all groups comparing objective parameters revealed an increase of papilla height between time points. A slight recession (0.26 mm) of the peri-implant mucosal margin at the implant site was observed between 1Y and 2Y. Mean values for PES and WES were 13.9 and 13.1 for the PFM group and for the all-ceramic group, respectively. These values were not statistically significant. Implant crown volume, outline, translucency, and characterization showed major discrepancies with the contra-lateral natural teeth. As for subjective parameters, VAS patients' responses regarding their perceptions of the esthetic outcome showed no statistical differences between groups and clinicians' accuracy scores were 50% and 47% for PFM and all-ceramic crowns, respectively.
Conclusion: PFM and all-ceramic single-implant restorations may be indistinguishable from each other regarding the objective/subjective assessment of esthetic integration. The material chosen for fabricating an implant crown per se does not ensure an optimal esthetic outcome if other esthetic parameters are not present.