| Abstract: | Third molar eruption is an unpredictable event. The position of the third molar continuously changes during development. The purpose of this study was to evaluate the influence of Bionator treatment on third molar position against an untreated control group. A Bionator is a loose‐fitting intra‐oral appliance that postures the mandible forward, thereby producing skeletal and dentoalveolar changes. Data were obtained from direct measurements of existing longitudinal panoramic radiographs taken during the course of a randomized study investigating Class II malocclusion treatment options. The following variables were analyzed: mandibular third molar depth in relation to the cemento‐enamel junction of the second molar; anterior–posterior (A–P) position in relation to the anterior border of the ramus; and angulation registered at the functional occlusal plane. Analysis of variance and ordinal logistic regression were used to investigate relationships between the variables. Angulation of the third molars changed substantially with varying depths (p<0.0008) and A–P positions (p<0.0001), but did not appear to relate appreciably to dental age (p>0.5) or treatment condition (p>0.4). The A–P position was significantly correlated to dental age (p>0.004) and Bionator treatment (p<0.0001), whereas depth was marginally associated with dental age (p<0.07) and not influenced by Bionator treatment (p>0.5). Third molars adopt a position further anterior in relation to the ramus with Bionator treatment than they do in controls. As dental age increases, Bionator use appears to positively influence third molar position. |
