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Clinical Outcomes of Vertical Distraction Osteogenesis for Dental Implantation: A Systematic Review and Meta-Analysis.

PURPOSE
The aim of this study was to evaluate the clinical outcomes of vertical distraction osteogenesis (VDO) for patients with vertically deficient alveolar ridges in terms of (1) the cumulative implant survival rate, (2) bone gain, (3) bone resorption before and after implant insertion, and (4) complications.


MATERIALS AND METHODS
An electronic search was conducted via MEDLINE (PubMed), EMBASE, and the Cochrane Library, complemented by manual searches, to identify eligible clinical studies of VDO before dental implantation. Two reviewers independently performed the study selection and data extraction. The implant survival rate, mean bone gain, and bone resorption amount, with 95% confidence intervals (CIs), were pooled separately. A random-effects model or fixed-effects model was chosen based on the heterogeneity. A funnel plot and Egger's test were performed to identify publication bias.


RESULTS
Of the 4,391 records after removal of duplicates, 113 full-text articles were obtained for further analysis, and 12 articles were ultimately included in the analysis. Two studies were defined as low quality. The estimated cumulative implant survival rate was 98.00% (95% CI: 96.02% to 99.40%), with a mean follow-up of 3.52 years. The bone gain was 7.92 mm (95% CI: 6.27 to 9.57 mm), with a range from 4 to 20 mm, and the level of bone relapse between the end of the distraction and the implant insertion was 0.97 mm (95% CI: 0.68 to 1.26 mm). The complication rate was high, with rates of 0.728 per site and 0.821 per patient. The most common major complication was basal bone fracture, with a rate of 2.27%, and the most common minor complication was displacement of the transport segments, with a rate of 16.71%.


CONCLUSION
Vertical alveolar defects could be rehabilitated successfully with distraction osteogenesis, and the implant placed in the distraction sites showed a high cumulative survival rate. However, the high complication rate necessitates caution. Due to the observed heterogeneity, the results of this meta-analysis should be interpreted with caution.