Overbite correction with fully customized lingual appliances

2013-04-09BACKGROUND: Overbite is the vertical relation of the upper to lower incisors. Normal overbite is considered normal within 1-3 mm, and excessive over 4 mm. ❧ OBJECTIVE: Goal of this study is to determine the mechanism of overbite correction with customized appliances. ❧ MATERIALS AND METHODS: Cephalometric radiographs for 39 consecutive cases with >4 mm. of overbite were digitized and traced in Dolphin Imaging Software. In order to assess changes, tracings were superimposed by the Bjork structural method. All cases were from a single orthodontic office in Germany and treated with Incognito lingual system. Sample was divided into growing and non-growing subgroups according to chronological age. Descriptive statistics and comparison between subgroups are presented. ❧ RESULTS: Treatment and growth changes in growing patients included: 1) molar extrusion 2) anterior incisor intrusion 3) anterior incisor flaring. Treatment and aging changes in growing patients included: 1) minimal molar extrusion 2) anterior incisor intrusion 3) greater anterior incisor flaring 4) mandibular autorotation. The difference between groups was the increase in facial heights. ❧ CONCLUSIONS: Growing and non-growing differed (as expected) in the increase of facial heights. Incisor inclination depended on the desired inclination designed into the custom lingual appliance as opposed to increased inclination (flared) incisors often reported in other studies. Overbite correction was a combination of molar extrusion, incisor intrusion, incisor flaring, and mandibular autorotation. Future research is needed to define the target overbite for specific patients in order to allow for optimum function