Prognostic implications of nasal cavity and cleft morphology in secondary bone grafting

To examine the prognostic significance of the skeletal morphology around the nasal cavity and the alveolar cleft in secondary bone grafting (SBG). Fifty-one alveolar clefts in 41 patients (10 bilateral and 31 unilateral cleft lips and palates) registered in the Tokushima University Dental Hospital were examined in this study. Evaluation of the bony bridge after SBG using dental radiographs at 1 year after surgery. The clefts were divided into two groups: group I (54.9%) in which the upper border of the bony bridge was preferably maintained on or above the horizontal reference line (RL) constructed at the level of the root apex of the upper central incisor adjacent to the cleft, and group II (45.1%) in which the bone level was lower than the RL. Presurgical cleft width was determined by the dental radiographs. The cleft/nasal cavity ratio; the value of the cleft width divided by the nasal cavity width on the cleft side, which was analyzed by frontal cephalograms before the SBG; and the cleft/apertura piriformis ratio, the value analyzed by computed tomography, were used. The age, sex, and eruptive stage of the canine teeth at the time of the SBG showed no significant difference between groups. The presurgical cleft width also showed no significant difference between group I (6.6 +/- 3.1 mm) and group II (7.9 +/- 3.3 mm). The cleft/nasal cavity ratio showed a significant difference between groups I and II (0.42 +/- 0.14, 0.75 +/- 0.25; p < .05). Furthermore, the cleft/apertura piriformis ratio also showed a significant difference between groups I and II (0.32 +/- 0.12, 0.65 +/- 0.26; p < .05). These results suggested that measurements of the skeletal morphology around the nasal cavity and alveolar cleft might aid in predicting the stability of the bony bridge after SBG.