Effects of modified abutment characteristics on peri-implant soft tissue health: A systematic review and meta-analysis

Objectives: The purpose of this systematic review was to evaluate the impact of the abutment characteristics on peri-implant tissue health and to identify the most suitable material and surface characteristics. Methods: A protocol was developed aimed to answer the following focused question: Which is the effect of the modification of the abutment design in regard to the maintenance of the peri-implant soft tissue health? Further subanalysis aimed to investigate the impact of the abutment material, macroscopic design, surface topography and surface manipulation. Randomised controlled trials (RCTs) with a follow-up of at least 6months after implant loading were considered as inclusion criteria. Meta-analyses were performed whenever possible. Results: Nineteen final publications from thirteen investigations were included. The results from the meta-analysis indicated that zirconia abutments (Zi) experienced less increase in BOP values over time [n=3; WMD=-26.96; 95% CI (-45.00; -8.92); p=.003] and less plaque accumulation [n=1; MD=-20.00; 95% CI (-41.47; 1.47); p=.068] when compared with titanium abutments (Ti). Bone loss was influenced by the method of abutment decontamination [n=1; MD=-0.44; 95% CI (-0.65; -0.23); p<.001]. The rest of the studied outcomes did not show statistically significant differences. Conclusions: The macroscopic design, the surface topography and the manipulation of the implant abutment did not have a significant influence on peri-implant inflammation. In contrast, the abutment material demonstrated increased BOP values over time for Ti when compared to Zi abutments.