Factors influencing the success of GBR - Smoking, timing of implant placement, implant location, bone quality and provisional restoration

The aim of this retrospective clinical study was to evaluate the influence of different factors on the outcome of GBR treatment. 75 patients, who were not randomly assigned to the investigated parameters for clinical reasons, were included in the study. They presented with defect sites around implan ts and were treated with a xenogenic grafting material and a resorbable col lagen membrane. The defect morphology was described, its dimension was meas ured and calculated at the time of implant installation and at re-entry. Th e success of GBR treatment was related to several clinical variables and po ssible correlations were evaluated. Defect sites around maxillary implants showed significantly more bone fill (96%) compared to those in the mandible (78%). The insertion of a provisional restoration during the healing perio d was also associated with significantly better results than when no provis ional was inserted. Immediate and short-term delayed implant placements sho wed the best results both with 92% bone fill, when compared with long-term delayed placements with 80% bone fill (n.s.). In sites with type I bone qua lity (compact bone), a reduced bone fill was observed (64%). The results in dicate that successful bone fill can be achieved with GBR; this is more fea sible in the maxilla, when a provisional restoration is used. Early implant placement timings seem to be preferable due to the alveolar ridge preserva tion, more favorable defect morphologies and a higher regenerative capacity .