C M Bollen

An in vivo Study of the Influence of the Surface Roughness of Implants on the Microbiology of Supra- and Subgingival Plaque

In nine patients with fixed prostheses supported by endosseous titanium implants, 2 titanium abutments (trans-mucosal part of the implant) were replaced by either an unused standard abutment or a roughened titanium abutment. After 3 months of habitual oral hygiene, plaque samples were taken for differential phase-contrast microscopy, DNA probe analysis, and culturing. Supragingivally, rough abutments harbored significantly fewer coccoid micro-organisms (64 us. 81%), which is indicative of a more mature plaque. Subgingivally, the observations depended on the sampling procedure. For plaque collected with paper points, only minor qualitative and quantitative differences between both substrata could be registered. However, when the microbiota adhering to the abutment were considered, rough surfaces harbored 25 times more bacteria, with a slightly lower density of coccoid organisms. The presence and density of periodontal pathogens subgingivally were, however, more related to the patients dental status than to the surface characteristics of the abutments. These results justify the search for optimal surface smoothness for all intra-oral and intra-sulcular hard surfaces for reduction of bacterial colonization and of periodontal pathogens.

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.