Microbial communities of titanium versus zirconia abutments on implant-supported restorations: Biodiversity composition and its impact on clinical parameters over a 3-year longitudinal prospective study.

Abstract

BACKGROUND\nShifts in microbial communities are common over time, but they may disturb the host-microbiome homeostasis and result in inflammation of the peri-implant issues if a dysbiotic biofilm is established.\n\n\nPURPOSE\nConsidering that different oral substrate surfaces may have a relevant impact on the microbial adhesion and colonization, the aim of this study was to investigate the microbial communities of the biofilm formed on single-implant restorations using titanium or zirconia abutments and how they correlate with clinical parameters after 3-years of implant loading.\n\n\nMATERIALS AND METHODS\nMiSeq sequencing of 16S rRNA amplicons was used to characterize the oral biofilms of individuals (n = 20) who were sampled longitudinally during 3\u2009years of masticatory loading. Bioinformatics analysis and multivariate statistical analysis were used to evaluate the microbial diversity and clinical outcomes.\n\n\nRESULTS\nMicrobiomes of both abutment materials presented high alpha-diversity indices during all the experimental period, irrespective of the time of sampling. Microbial communities of titanium and zirconia were quite different over time, differing about 30% after 3\u2009years of functional loading. Similarity of microbiomes between tested abutments and contralateral teeth was also low, ranging between 45% and 50% after 3\u2009years of investigation. Periodontal pathogens commonly associated with peri-implantitis were found in both groups. Furthermore, both abutment materials presented strong correlations of diversity indices and microbial taxa with clinical outcomes.\n\n\nCONCLUSIONS\nThe type of abutment substrate significantly influenced diversity and clustering of communities during 3\u2009years of functional loading. The time of sampling had no effect on the variables. Large correlations were found between microbial findings and clinical outcomes.