Peri-implant marginal bone changes with implant-supported metal-ceramic or monolithic zirconia single crowns: A retrospective clinical study of 1 to 5 years

Abstract

Statement of problemMonolithic zirconia has excellent mechanical and biologic properties. However, evidence of the clinical properties of implant-supported monolithic zirconia prostheses is limited. PurposeThe purpose of this retrospective clinical study was to compare the peri-implant marginal bone changes of metal-ceramic and monolithic zirconia single crowns in the posterior region after prosthetic loading. Material and methodsA total of 224 participants treated with 327 implants restored with either metal-ceramic or monolithic zirconia single crowns in the posterior region between 2012 and 2016 were included in this study. Clinical outcomes, including the plaque index, peri-implant probing depth, and bleeding on probing, were recorded, and the marginal bone level was recorded by using the panoramic radiographs obtained at implant placement, second-stage surgery, and the most recent follow-up visit. The included parameters were analyzed with the nonparametric Mann-Whitney tests (α=.05). ResultsThe mean follow-up time was 30.4 months, and the cumulative survival rate of implants was 100% and that of the prostheses was 99.1%. The plaque index was 0.46 in the metal-ceramic group, which was significantly higher (P<.05) than 0.37 in the monolithic zirconia group. However, no significant differences (P>.05) were observed in peri-implant probing depth and bleeding on probing between the 2 groups. The marginal bone level at implant placement, second-stage surgery, and the most recent follow-up visit was above the implant platform in both the metal-ceramic and monolithic zirconia groups. The marginal bone changes of the metal-ceramic group was 0.31 mm in the healing period and 0.38 mm in the prosthetic loading period, while in the monolithic zirconia group, it was 0.25 mm in the healing period and 0.43 mm in the prosthetic loading period; no significant differences (P>.05) were observed between the 2 groups. ConclusionsThe peri-implant marginal bone level change was comparable after prosthetic loading for metal-ceramic and monolithic zirconia single crowns, although monolithic zirconia was associated with reduced plaque.