Purpose: This review aimed to summarize the current literature on the oral biofilm formation on alternative abutment materials compared with titanium (Ti) or Ti alloy in clinical and in situ conditions.
Materials and methods: An electronic database search was conducted in PubMed, Cochrane Library, EMBASE, Scopus, Web of Science, LIVIVO, BVS, ProQuest, and OpenGrey up to November 2020. Clinical and in situ studies evaluating the biofilm formed on metallic, ceramic, or polymeric abutment materials compared with Ti or Ti alloy were included. Outcome measures were microbial counts/profile, cell viability, and biofilm coverage/thickness. Clinical parameters were deemed secondary outcomes. Risk of bias was assessed by RoB 2 and ROBINS-I tools.
Results: A total of 10 clinical and 9 in situ studies were included. Meta-analysis was not performed due to heterogeneity across studies. The abutment materials polytetrafluoroethylene, gold alloy, gold-platinum alloy, cobalt-chromium, alumina, and zirconia were reported. Six out of ten clinical studies (60%) and four out of nine in situ studies (44%) found no qualitative or quantitative microbiologic differences between tested materials. When significant differences were detected, conflicting results were reported. Clinical outcomes were consistent with healthy conditions for all investigated materials.
Conclusion: There is not enough evidence to support the existence of relevant microbiologic differences in the biofilm formed on alternative abutment materials over Ti and its alloys in oral conditions. No evident relationship between microbiologic results and clinical outcomes were found. In situ studies and polymicrobial analyses showed a higher tendency to find significant differences between materials.