Clinical study of horizontal alveolar distraction with modified micro bone screws and subsequent implant placement

The aim of this study was to evaluate the clinical relevance of horizontal distraction osteogenesis (DO) with bone micro screws for reconstructing knife-edge alveolar crests before implant placement. Horizontal DO was performed in upper and lower alveolar crests of seven patients with resorption class IV according to Cawood and Howell. After osteotomy and a 1-week latency period, micro bone screws were reset daily for horizontal expansions by 0.5 mm. Dental implants were placed in the distracted area following a consolidation period of 12 weeks. Computer tomography was performed before DO and implant placement. Morphometric analysis showed a mean gain of 34.01 mm(2) (95% confidence interval [CI]: 10.55-57.48) in bone area and of 3.06 mm (95% CI: 1.81-4.31) in horizontal width, i.e. the horizontal dimension of the alveolus was approximately doubled within the first 5 mm of height. All 12 implants placed into the distracted area fulfilled the success criteria of stable osseointegration after 1 year of functional loading according to Albrektsson and colleagues. Despite the limited number of patients treated, data from the clinical study of horizontal DO with bone micro screws suggest that the generation of sufficient hard tissue in previously knife-edge alveolar crests for subsequent implant placement was possible.