ABSTRACT
OBJECTIVE: This retrospective study was conducted to analyze changes in the maxillary permanent molars after monobloc advancement with rigid external distraction (RED). SETTING: University hospital-based craniofacial center. MATERIALS AND METHODS: Fourteen patients, three in primary, eight in mixed, and three in permanent dentition underwent monobloc advancement with RED. After a latency period of 6 days, distraction was carried out for 18 days. Lateral cephalometric radiographs were taken before surgery (T1) and an average of 3.72 months after the removal of the distractor (T2). Panoramic radiographs were taken at T1, T2, and T3 (an average of 14.87 months after RED removal), to search for surgical tooth trauma, arrested crown/root development, impaction, tooth germ displacement, dilacerations, and other possible dental abnormalities. Vertical and horizontal displacement and angulations of the permanent maxillary molars were evaluated before and after surgery. STATISTICS: A paired t test was used to analyze significant changes in molar position after distraction. RESULTS AND CONCLUSIONS: Distraction created posterior arch length with significant horizontal forward movement of the first and second molars (p<.05) and minimal vertical displacement (p>.05). The procedure disrupted the development of one of the first molars, three of the second molars, and two of the third molars. Incidence of molar damage was increased in patients operated on during primary dentition. Careful surgical technique during pterygomaxillary disjunction, especially in young children, and long-term radiographic follow-up of maxillary molars is strongly recommended.
