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

Aim of the study

To evaluate the influence of different factors on the outcome of guided bone regeneration (GBR).

Materials and methods

75 patients presenting with peri-implant bone defects were treated with xenografts (Bio-Oss^®) in association with resorbable collagen membranes (Bio-Gide^®). Measurements were carried out at the time of implant insertion and at re-entry (after 4 months in the mandible and 6 months in the maxilla).

Results and conclusions

The best results for GBR were obtained in the maxilla (96 % bone fill against 78 % in the mandible) and with the use of a provisional restoration during the healing phase. The immediate placement of the implants gave better results compared with those placed after a long interval. Regeneration is limited in the presence of compact bone (Type I bone quality). Tobacco use did not produce negative effects. Early placement of implants seemed to be preferable because the morphology of the defect is preserved and the bone has a higher capacity for regeneration.

Commentary

There are many factors which influence GBR. The most important element in this study was the site, the maxillary area being much more favourable for bone grafting.