Cephalometric configuration of the occlusal plane in patients with anterior open bite

• Dentoalveolar tooth heights were compared in open-bite and normal occlusions.
• K-clustering was used to divide open-bite subjects into 2 groups, V-form and Y-form.
• Dentoalveolar heights of 4 mandibular teeth were greater in the Y-form group.
• Dentoalveolar heights of 5 maxillary teeth were greater in the open-bite group.
• Open bite may be caused by overeruption of the maxillary molars.

IntroductionThis study was performed to investigate the cephalometric configuration of the occlusal plane in patients with anterior open bite.MethodsOf 61 subjects with open bite (overbite ≥3.75 mm) who had been recruited consecutively from January 2006 to November 2013 and had no history of orthodontic treatment, 14 cephalometric landmarks indicating the incisal edge or the buccal or mesiobuccal cusp tips of each tooth were used for K-means clustering to classify the occlusal plane configuration. For the open-bite group and a control group with normal occlusion (n = 38), dentoalveolar height, which is the perpendicular distance of each tooth to the palatal or mandibular plane, was compared among the clusters and between the 2 groups.ResultsThe open-bite subjects were divided into 2 clusters according to occlusal contact of the premolars: Y-form and V-form (with and without premolar contact, respectively). The normalized dentoalveolar heights of the 4 mandibular teeth (lateral incisor to second premolar) were significantly greater in the Y-form class than in the V-form class. The dentoalveolar heights of the 5 maxillary teeth (lateral incisor to first molar) were significantly greater in the open-bite group than in the control group.ConclusionsFor anterior open-bite treatment, the cephalometric configuration of the occlusal plane should be considered based on the occlusal contacts of the premolars.