Soft tissue surrounding switched platform implants : an immunohistochemical evaluation

Objectives This clinical and immunohistochemical study was designed to characterize the cellular and molecular patterns for bone loss of soft tissues surrounding implants restored with different implant platform configurations. Material and methods A total of 32 implants were restored using abutments with the following mismatches: 0 mm (control group), 0.25 mm (test group1), 0.5 mm (test group2) and 0.85 mm (test group3). Four years after, loading all sites were clinically healthy, and soft tissue samples were harvested and processed for immunohistochemical analysis. Amounts of lymphocytes T (LyT) -B (LyB), IL-17 and RANKL were assessed. Results No significant difference was found between groups (P > 0.05) in terms of infiltrated T and B cell counts, IL-17 and RANKL expressions. When pooled data were analysed, lymphocytes T counts and IL-17 were higher than lymphocytes B counts and RANKL. LyT and LyB counts were highly negatively correlated (Pearson's r > 0.7) and IL-17 was correlated (Pearson's r > 0.4, <0.7) to LyT and LyB. Conclusions After prolonged exposure of abutments in the oral cavity, the configuration of the implant abutment interface does not seem to affect the inflammatory cellular and molecular pattern responsible for bone loss.