Gingival clefts revisited: Evaluation of the characteristics that make one more susceptible to gingival clefts.

INTRODUCTION: Orthodontic space closure after premolar extraction commonly results in the formation of a gingival cleft, which may contribute to orthodontic relapse and poor periodontal health. The purpose of this study was to examine clinical parameters that may predispose patients to gingival clefts.

METHODS: Twenty-nine patients planned for treatment with premolar extractions (n = 87) and orthodontic space closure were evaluated in this prospective study. The clinical measures included width of keratinized buccal gingiva, thickness of buccal gingiva, thickness of buccal bone, time of space closure, and the occurrence (presence or absence) and severity (volume) of cleft formation. The association of the clinical measures with gingival cleft formation and severity was assessed separately for patients according to age group: young adolescent (≤13 years of age), adolescent (14-18 years of age), and adult (≥19 years of age).

RESULTS: The overall incidence of gingival cleft formation was 73.2%, with a trend toward greater cleft formation in the young adolescents (79.4%) than in the adolescent and adult groups (69.2% and 68.2%, respectively). The mean severity of clefts exhibited a significant positive association with age group-young adolescent (26.6 mm2 ), adolescent (27.9 mm2 ), and adult (41.5 mm2 ). Buccal bone thickness was significantly correlated with gingival phenotype in the adolescent and adult groups (r = 0.42 and r = 0.52, respectively; both, P <0.05). Rate of space closure was significantly correlated with cleft formation (r = 0.71; P <0.001) in the adult group.

CONCLUSIONS: The formation of gingival clefts is common after premolar extraction and space closure. Adults with a thinner gingival phenotype were more likely to develop gingival clefts of greater severity. The rate of space closure was significantly and inversely correlated with cleft formation in adults, reflecting a greater likelihood of cleft formation with slower space closure. Although various clinical parameters show a correlation to both severity and incidence of clefts, all patients undergoing postextraction space closure appear to be at risk and should be monitored.