Alterations of the bone dimension following immediate implant placement into extraction socket: systematic review and meta-analysis

Aim: This systematic review was aimed at analysing bone dimensional alterations within the first year following immediate implant placement. Materials and Methods: The electronic search was conducted using MEDLINE (PubMed), Cochrane Central Register of Controlled Trials (CENTRAL) and EMBASE from January 1980 to October 2013. Quality assessment of selected articles was performed using Cochrane Collaboration's tool or Newcastle-Ottawa scale according to the design of each study. A meta-analysis was performed to estimate bone dimensional reduction. Weighted mean differences in bone dimension between baseline and follow-up measurement were calculated. Subgroup analysis and mete-regression were conducted to evaluate the effects of different variables. Results: A total of 1348 articles were identified following the search process. Six studies were included in the present review. The weighted mean buccal horizontal bone dimensional reduction (BHDr) was 1.07 mm and buccal vertical bone dimensional reduction (BVDr) was 0.78 mm. The weighted mean palatal bone dimensional reduction was 0.62 mm horizontally (PHDr) and 0.50 mm vertically (PVDr). The initial thickness of the buccal alveolar plate (TB) of the socket was the only variable significantly correlated with BHDr and BVDr in meta-regression analysis. Conclusions: The bone dimensions of immediate implant sites demonstrated approximately 0.5-1.0 mm reduction in vertical and horizontal aspects 4-12 months following surgery. The results should be interpreted with care because of the data heterogeneity. The correlation of the socket buccal wall thickness, and other variables, with dimensional changes of the bony ridge should be investigated further in controlled clinical trials.