Long-term results of implants treated with guided bone regeneration: A 5-year prospective study

The aim of this prospective 5-year longitudinal study was to follow endoste al implants in which guided bone regeneration (GBR) was applied during impl ant placement. In 75 patients, defects around implants (Branemark System) w ere treated with Bio-Oss and Bio-Gide (112 implants). In split-mouth patien ts in this group, Bio-Oss and Gore-Tex were used in the second defect site (41 implants). All 75 patients had at least 1 implant that was entirely sur rounded by bone and served as the control (112 implants). After placement o f the definitive prostheses (single-tooth, fixed, or removable implant pros theses), patients were recalled after 6 months and then every 12 months dur ing a 5-year observation period. The following variables were investigated: implant survival, marginal bone level (MBL), presence of plaque, peri-impl ant mucosal conditions, height of keratinized mucosa (KM), and marginal sof t tissue level (MSTL), The cumulative implant survival rate after 5 years v aried between 93% and 97% for implants treated with or without GBR. The mea n MBL after 60 months was 1.83 mm for sites treated with Bio-Oss and Bio-Gi de, 2.21 mm for sites treated with Bio-Oss and Gore-Tex, and 1.73 mm for th e control sites, The MBL values were found to increase significantly with t ime and differed significantly among the treatment groups, During the obser vation period, KM varied between 3.16 and 3.02 mm, A slight recession of 0. 1 mm was observed, and plaque was found in 15% of all sites and was associa ted with inflammatory symptoms of the peri-implant mucosa, It was observed that such symptoms and recession correlated more strongly with the type of restoration than with the type of treatment. This study demonstrated that i mplants placed with or without GBR techniques had similar survival rates af ter 5 years, but that bone resorption was more pronounced in sites with GBR treatment. It was assumed that the use of GBR is indeed indicated when the initial defect size is larger than 2 mm in the vertical dimension.