RÉSUMÉ
Aim: resorption of alveolar bone following tooth loss represents a major limitation in the use of dental implants. Procedures of ridge or socket preservation have been introduced to maintain bone dimensions and enable prosthetically driven implant positioning, yet circumventing two-stage bone graft surgery. The aim of the present systematic review and meta-analysis was to quantify reduction of alveolar ridge resorption in horizontal as well as vertical dimension (compared to untreated controls) reported in clinical trials on alveolar ridge grafting. Materials and Methods: systematic electronic and hand searches yielded 4 investigations published between 2000 and 2009 that met the inclusion criteria. A total of 74 ridge preservation procedures and 61 control sites were evaluated 6-7 months after surgery. Results: mean loss of bone height and width was 0.3 mm and 2.5 mm after ridge preservation surgery compared to 1.2 mm and 3.5 mm in the control group, respectively. Prevention of horizontal shrinkage (mean: 28%, range: 12-55%, OR = 1.6) was significantly less effective (p = 0.034) than reduction of vertical bone resorption (mean: 74%, range: 60-88%, OR = 4.9). Conclusion: alveolar ridge preservation may be effectively used to increase available bone height and width by 1 mm, on average