The influence of abutment surface roughness on plaque accumulation and peri‐implant mucositis

Abstract

Bacterial adhesion to intra-oral, hard surfaces is firmly influenced by the surface roughness to these structures. Previous studies showed a remarkable higher subgingival bacterial load on rough surfaces when compared to smooth sites. More recently, the additional effect of a further smoothening of intra-oral hard surfaces on clinical and microbiological parameters was examined in a short-term experiment. The results indicated that a reduction in surface roughness below R(a) = 0.2 microns, the so-called "thresholds R(a)", had no further effect on the quantitative/qualitative microbiological adhesion or colonisation, neither supra- nor subgingivally. This study aims to examine the long-term effects of smoothening intra-oral hard transgingival surfaces. In 6 patients expecting an overdenture in the lower jaw, supported by endosseus titanium implants, 2 different abutments (transmucosal part of the implant): a standard machined titanium (R(a) = 0.2 microns) and one highly polished and made of a ceramic material (R(a) = 0.06 microns) were randomly installed. After 3 months of intra-oral exposure, supra- and subgingival plaque samples from both abutments were compared with each other by means of differential phase-contrast microscopy (DPCM). Clinical periodontal parameters (probing depth, gingival recession, bleeding upon probing and Periotest-value) were recorded around each abutment. After 12 months, the supra- and subgingival samples were additionally cultured in aerobic, CO2-enriched and anaerobic conditions. The same clinical parameters as at the 3-month interval were recorded after 12 months. At 3 months, spirochetes and motile organisms were only detected subgingivally around the titanium abutments. After 12 months, however, both abutment-types harboured equal proportions of spirochetes and motile organisms, both supra- and subgingivally. The microbial culturing (month 12) failed to detect large inter-abutment differences. The differences in number of colony- forming units (aerobic and anaerobic) were within one division of a logarithmic scale. The aerobic culture data showed a higher proportion of Gram-negative organisms in the subgingival flora of the rougher abutments. From the group of potentially "pathogenic" bacteria, only Prevotella intermedia and Fusobacterium nucleatum were detected for anaerobic culturing and again the inter-abutment differences were negligible. Clinically, the smoothest abutment showed a slightly higher increase in probing depth between months 3 and 12, and more bleeding on probing. The present results confirm the findings of our previous short-term study, indicating that a further reduction of the surface roughness, below a certain "threshold R(a)" (0.2 microns), has no major impact on the supra- and subgingival microbial composition.

Relevance of surface characteristics in the adhesiveness of polymicrobial biofilms to crown restoration materials

“…Shintani (14) reported that plaque adhesion increases on rougher surfaces. In contrast, Bollen et al reported that Ra values less than 0.2 µm do not affect bacterial adhesion (28), and a study by Nascimento et al showed that bacterial adhesion to titanium and zirconium was insensitive to Ra (29). However, Dorkhan et al reported high bacterial adhesion on rough surfaces coated with saliva (30) and found that adhesion to composite resin is not influenced by surface characteristics.…”

Adhesion of Streptococcus sanguinis to Dental Implant and Restorative Materials in vitro

“…Generally, rough surfaces promote bacterial adhesion whereas smooth surfaces minimize it [13][14][15] . According to Bollen et al 16) , surface roughness below Ra=0.2 m had no further quantitative and qualitative effects on bacterial adhesion. Moreover, variations around this value had only a negligible impact on bacterial adhesion.…”

Comparative Analysis of Surface Topography of Custom CAD/CAM ZirconiaAbutments by means of Optical Profilometry

“…12 Studies confirm that a roughness of Sa= 0.2 μm can be accepted as a threshold; significantly exceeding this promotes the risk of mechanical plaque retention. 13 However, 4 roughness should not be critically below this threshold to facilitate soft-tissue adherence and avoid loss of attachment.…”