Effect of restoration material on marginal bone resorption around modified anatomic zirconia dental implants: A randomised controlled trial

OBJECTIVE: The primary aim of this study was to determine the effect of implant-supported porcelain-fused-to-metal (PFM) and indirect-composite-resin (ICR) fixed dental prostheses on peri-implant marginal bone resorption (MBR) in custom-made anatomic modified zirconia dental implants. METHODS: A prospective randomized controlled clinical trial was conducted. Participants with premolars indicated for dental extractions were recruited into this study to receive a single-unit implant-supported fixed dental prosthesis. Modified anatomic zirconia implants with thorny-retentive surfaces were placed and loaded randomly after 3 months with either PFM or ICR crowns. Participants were recalled after 12 and 18 months for radiographic evaluation of peri-implant MBR. Implants survival was also reported. RESULTS: 18 out of 20 zirconia implants were included in all study phases. 18-month survival rate was 90%. After 12 months of implant placement, the mean MBR values were 0.53 (±0.21) mm and 0.60 (±0.14) mm in the ICR group compared to 0.67 (±0.16) mm and 0.61 (±0.27) mm in the PFM group. In the 18-month follow-up, the mean MBR values were 0.61 (±0.27) and 0.67 (±0.16) mm in the ICR group compared to 0.77 (±0.29) and 0.77 (±0.27) mm in the PFM group. No significant differences were found in MBR mean values between study groups at 12- and 18-month follow-up points. CONCLUSION: This study showed that PFM and ICR crowns were viable zirconia-implant-supported restorations with no preference regarding MBR after 18 months. Nevertheless, long-term evaluations are warranted.