Clinical relevance of the influence of surface free energy and roughness on the supragingival and subgingival plaque formation in man

Abstract

Previous clinical studies illustrated a positive correlation between the rate of “supragingival” plaque maturation and both the free energy and roughness of the intraoral hard surfaces (teeth, prostheses, implants). The present review of the literature aims to examine the clinical importance of these parameters especially in the “subgingival” environment, where plaque causes periodontitis. Despite the clear cut differences between supragingival and subgingival environments (with more possibilities for adhesion and fewer removal forces for the latter), both the surface roughness and the surface free energy remain important. This could be proven in an in vivo study in patients with implant-supported prostheses, where abutments (trans-mucosal connections between implant in the bone and prosthetic reconstruction) with different surface characteristics were examined. After an undisturbed subgingival plaque formation of 3 months, the roughened surfaces harboured significantly more bacteria (51 × 10 4 colony-forming units (CFU)) than both smooth abutments (3 × 10 4 CFU), and fluorinated ethylene-propylene (FEP) coated abutments with comparable roughness (11 × 10 4 CFU). The plaque composition was also slightly surface dependent, with a more pathogenic situation around the roughened titanium abutments. However, if the “in the pocket swimming flora” was considered, most differences disappeared.