Response of soft tissue to different abutment materials with different surface topographies: a review of the literature.

Soft tissue integration in the transmucosal zone of dental abutments supports the peri-implant tissues, improves esthetics, ensures soft tissue seal against microorganisms, and preserves crestal bone level. The aim of this literature review was to define the most favorable surface topography and macrodesign of the transmucosal zone of abutments to achieve optimal soft tissue seal. An electronic search of the PubMed/MEDLINE database was performed, seeking relevant English-language articles published between January 1, 2003, and October 11, 2014. The key terms implant abutment, surface topography, and soft tissue seal were used both singly and jointly with "AND" in this search. Additionally, a manual search was performed. Articles that did not distinguish between abutment and implant surfaces, investigated only 1-piece dental implants, or were systematic reviews were excluded, although 4 systematic reviews were studied to obtain background information. Out of a preliminary pool of 206 articles, 12 relevant articles were identified for final evaluation in addition to the 4 systematic reviews. These included 3 human studies, 3 animal studies, and 6 in vitro studies. The human histologic studies showed evidence of perpendicular insertion of human gingival fibroblasts into the treated abutment surface. Laser-ablated, hydrophilic, and oxidized titanium surfaces resulted in this type of attachment. Epithelial cells seem to slightly favor zirconia and polished titanium surfaces. Due to heterogeneity in the study designs, statistical methods, and reported results, meta-analysis of the data was not possible. Improvements in the surface topography and macrodesign of dental abutments might improve biocompatibility and adherence to soft tissue; however, manipulation of soft tissue and second-stage surgery could negate any advantages of the improved surfaces.