Factors influencing secondary alveolar bone grafting in cleft lip and palate patients: prospective analysis using CT image analyzer.

OBJECTIVE

To examine the effect of migration of the germ of the lateral incisor into the bone for eruption factors on bone bridge resorption.

METHODS

Twenty-five subjects who underwent secondary alveolar bone graft were enrolled. The volume of the alveolar bone grafts immediately after the operation (V1), bone bridge formation 6 months postoperatively (V2), and tooth (teeth) migration into the bone bridge (Vt) were measured using a computed tomography (CT) image analyzer. Based upon these measurements, the following points were examined: (1) the correlation between the tooth-occupied ratio (Rt = Vt/V2 x 100) and the ratio of bone bridge resorption (Rv = (V1 - V2)/ V1 x 100); and (2) comparison of the tooth-occupied ratio (Rt) and the ratio of bone bridge resorption (Rv) between the groups with and without the germ of the lateral incisor.

RESULTS

A significant negative correlation was found between Rv and Rt (p < .001). Comparison of Rv and Rt between the groups with and without a germ of the lateral incisor revealed that both indices were significantly higher in the former group than the latter one (p < .05).

CONCLUSION

In cleft lip and palate patients with a germ of the lateral incisor, it is beneficial to carry out secondary bone grafting to the alveolar cleft at the age of 5 to 7 years, preceding eruption of the canine, in order to form a good bone bridge that will facilitate eruption of the lateral incisor and subsequent normal dentition and occlusion.