Technical Complications and Marginal Bone Loss Depending on the Crown Material of Dental Implants in the Posterior Region: A 3‐Year Randomized Clinical Study

Background/Objectives: This single-center, randomized controlled clinical trial evaluated the impact of two crown materials—lithium disilicate (LS2) and a polymer-infiltrated hybrid ceramic (HC)—on marginal bone loss (MBL) and technical complications in implant-supported single-tooth restorations over a three-year period. Methods Sixty patients with posterior single-tooth gaps were randomly assigned to receive either LS2 or HC crowns on iSy (Camlog) implants. All restorations were fabricated as CAD/CAM-based hybrid abutment crowns bonded to prefabricated titanium bases. Standardized radiographs were taken at baseline (T0) and at three years (T1) to assess MBL using ImageJ software. Technical complications were prospectively recorded. Data analysis was descriptive and exploratory. Results: Fifty-eight cases were available for final evaluation. The three-year implant survival rate was 100%. Mean marginal bone remodeling was minimal (mesial: LS2 0.15 mm, HC 0.08 mm; distal: LS2 0.13 mm, HC 0.12 mm), with no statistically significant intergroup differences. Bone apposition was observed in 74.1% of cases. Male patients showed significantly greater mesial bone loss (p = 0.024). Technical complications occurred more frequently in the HC group, including crown fractures (25%), decementation (17.9%), and screw loosening (14.3%). In the LS2 group, only screw loosening (12.5%) was observed. Conclusions: Lithium disilicate-based hybrid abutment crowns demonstrated high clinical reliability with stable peri-implant bone and fewer technical complications over three years. In contrast, hybrid ceramic crowns were associated with a higher rate of mechanical failure. Material selection should therefore be a key consideration in planning implant-supported single-tooth restorations.