A study of closed miniscrew anchorage in intrusion of mandibular incisors to correct deep overbite in adult patients

Abstract

Objective The purpose of this study is to investigate the effectiveness of the mandibular incisors intrusion by using closed miniscrew anchorage to correct the deep overbite in adult patients. Methods The sample comprised 20 adult patients with deep overbite who met the inclusion criteria. After surgical exposure of mandibular symphysis, one miniscrew was placed and closed up. Stainless steel ligature wire was tied with one end to miniscrew and the other end forming a cook exposed in oral cavity for later intrusion of mandibular incisors. Pre- and post-treatment cephalometric radiographs were measured and compared. Results All the patients had their deep overbite corrected, with an average decrease of 4 mm (P<0.001). The resistant center of mandibular incisors was intruded 2.8 mm remarkably (P<0.001). Meanwhile, significant labial proclination of the mandibular incisors were observed with increases in L1/MP and L1/NB (5.8° and 2.3°, respectively) and the decrease in Ul/L1 (P<0.01). With lower incisor intrusion and inclination, occlusal plane showed clockwise rotation, and the post-treatment MP/OP decreased significantly by 3.5°(P<0.001). The mandibular molars did not change significantly in inclination and vertical dimension. No significant root resorption of the incisors was found. Conclusions Intrusion of mandibular incisors through miniscrew anchorage could be used as an efficient method to correct deep overbite in adult patients. Key words: Miniscrew anchorage; Closed traction technique; Mandibular incisor intrusion; Deep overbite