A Systematic Review of Titanium Surface Properties for Reduced Biofilm Formation Based on Human Studies

Objectives: To systematically review if titanium rough surfaces are more susceptible to biofilm formation, when compared to smoother surfaces.
Methods: Eligibility criteria were settled to include studies that analyzed biofilm formation at human oral cavity of different titanium surfaces, based on roughness parameters. Evaluation was performed independently by two reviewers. Protocol was registered at PROSPERO (ID 177809). From the initial 5286 papers identified, 13 studies were included. Groups of individual studies were divided as smoother titanium surface (STS) and rougher titanium surface (RTS). Electronic database searches in PubMed, Web of Science and Scopus were performed up to January 2021, complemented by hand search. Mendeley Desktop was used to select papers. The Checklist for Quasi-Experimental Studies from The Joanna Briggs Institute Critical Appraisal was used to evaluate Risk of Bias.
Results: Splint systems with titanium specimens were orally exposed from 30 minutes to 31 days in healthy individuals. Studies analyzed biofilm formation at a machined titanium surface (STS) compared with a surface-treated titanium surface (RTS). STS mean roughness varied from 0.04 to 0.771µm. RTS values varied from 0.201 to 2.142µm. More surface contamination was commonly found at RTS when compared to STS surfaces. None of included investigations reported less biofilm formation at STS groups. Outcomes reliability was affected by lack of statistical analysis on roughness groups determination.
Conclusions: It is suggested that surface contamination is more common at rough than at machined titanium surfaces. Recommendations are settled in order to standardize future research to achieve stronger evidence.