The Impact of Implant Abutment Angle and Height on Peri-implant Tissue Health: Retrospective Analyses from a Randomized Controlled Clinical Trial

PURPOSE: Implant abutment design may influence the predisposition of peri-implant sites to develop peri-implant inflammation, especially peri-implantitis. Therefore, the objectives of the current study were to examine the influence of (1) abutment emergence angle and, (2) abutment height on marginal periimplant bone stability in patients not considered susceptible to peri-implantitis. Furthermore, it was analyzed (3) whether Ti-Base abutments lead to wider abutment emergence angles as compared to onepiece abutments. MATERIALS AND METHODS: 48 abutments (i.e., 24 Ti-base- and 24 one-piece abutments in 24 patients) have been at abutment installation, after one year, and thereafter on a yearly basis for up to five years. Clinical and radiographic outcome variables were assessed. RESULTS: With regard to peri-implant marginal bone stability, (1) only moderately negative, albeit significant, correlations were found on the mesial sides of the one-piece abutments after 4 and 5 years for an abutment emergence angle >30° and no statistically significant negative correlations were found between a distance of less than or equal to versus more than 1.5 mm between the restoration margin and the crestal peri-implant bone level, neither for Ti-Base nor for one-piece abutments. Furthermore, (3) abutments bonded to Ti-bases are not associated with larger emergence angles than one-piece abutments. CONCLUSION: For patients at low risk of developing peri-implantitis it can be concluded, that neither (1) a larger abutment emergence angle (>30°) nor (2) a distance of less than or equal to 1.5 mm between the restoration margin and the crestal peri-implant bone level are per se associated with marginal periimplant bone loss. Furthermore, (3) abutments bonded to Ti-bases are not as such associated with wider emergence angles than one-piece abutments. Int J Prosthodont 2023. doi: 10.11607/ijp.8138.