Overcorrection in vertical alveolar distraction osteogenesis for dental implants

A decrease in bone height following alveolar distraction osteogenesis (DO) before implant placement is common, and can be severe when alveolar DO is performed soon after surgical intervention. The aim of this study was to investigate the decrease in bone height after vertical alveolar DO and determine the need for overcorrection with implant placement. Thirty-five patients (17 males and 18 females, mean age 43.9 years) underwent 38 procedures with successful placement of 141 dental implants. Alveolar ridge height was evaluated using digital orthopantomographic radiographs taken shortly after the end of distraction, at consolidation and before implant placement. The mean distraction was 9.7 mm. The total vertical alveolar bone decrease was 2.1 mm (21%) during the consolidation period and 3.6 mm (37%) at implant placement. Although the 20 sites with a healthy alveolus (surgery >6 months) had bone reductions of 1.5 and 2.5 mm (15 and 25%) the 18 sites at which alveolar DO was performed within 6 months (mean 3.0) of surgical intervention had much greater bone loss of 2.7 and 4.8 mm (28 and 50%), respectively (**P < 0.01). These results indicate that any alveolar DO protocol should include a waiting period after the surgical intervention, as well as consider an overcorrection of more than 25% within the limits of the applied surgical protocol.