Posterior crossbite in the deciduous dentition period, its relation with sucking habits, irregular orofacial functions, and otolaryngological findings.

Introduction: The aim of this study was to assess unilateral posterior crossbite, sucking habits, orofacial functions, and otolaryngological findings in the deciduous dentition. These findings would allow us to establish a preventive program for posterior crossbite, based on interceptive treatment at an early stage of dental development. We would determine the predictive value for posterior crossbite development in correlation with the duration of sucking habits.

Methods: Data were collected on 30 children (13 boys, 17 girls) with unilateral posterior crossbite (mean age, 5.5 years; range, 3.6-7.2 years) and 30 children (17 boys, 13 girls) without crossbite (mean age, 5.9 years; range, 5.4-6.7 years), randomly selected from a local kindergarten. Information about each subject's nutritive and nonnutritive sucking behaviors was collected through parent interviews and questionnaires. An orthodontist and an otolaryngologist clinically examined all the children. Study models were obtained from all children, and dental arch parameters including arch widths in the canine and second deciduous molar regions were measured directly from the models. The data were then compared between the posterior crossbite and the noncrossbite groups.

Results: The results indicated correlations between prolonged pacifier sucking habit (P = 0.001), short frenulum linguae (P <0.001), smaller maxillary arch width (P <0.001), greater mandibular arch width (P <0.002), and unilateral posterior crossbite. A receiver operating characteristic curve was plotted for the pacifier sucking time. The borderline for the development of posterior crossbite suggested by the receiver operating characteristic curve was 18 months of pacifier sucking duration. The odds ratios between the crossbite and noncrossbite groups were 3.6 (CI = 0.97-13.4) for pacifier habit duration of 18 to 35 months and 21.9 (CI = 3.7-129.4) for pacifier suckers of more than 36 months. No significant correlation between enlarged adenoids and tonsils or impaired nasal breathing and the crossbite was found.

Conclusions: These results suggest that the duration of a pacifier habit and a short frenulum linguae are associated with posterior crossbite at the age of 4 or 5 years because of the low tongue posture in the mouth. Pediatricians and pedodontists should give precise recommendations for enhancing breast feeding and discontinuing pacifier habits at least until the child is 18 months of age. Further studies are also needed to determine more objectively the etiology of tongue posture, swallowing pattern, and the length of the frenulum linguae in children with posterior crossbite.