Author(s)

Morio Masunaga¹, Hiroshi Ueda^2*, Tatsuya Shibaguchi¹, Kazuo Tanne²

¹Masunaga Orthodontic Office, Osaka, Japan.
²Department of Orthodontics and Craniofacial Developmental Biology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.

Objective: The aim of study was to evaluate the nature of mesiodistal angulation of the posterior teeth in patients with maxillary high canine, and to identify possible associations of crowding with mesial axial angulation of the maxillary posterior teeth. Methods: The present study included seven Japanese male and 23 Japanese female patients. Study models were analyzed to evaluate the effectiveness of orthodontic treatment. A protractor was used to measure crown angulations, which were measured with reference to the posterior angle between the functional occlusal plane (FOP) and the long axis of the clinical crown of the lateral teeth and first molars. A sliding digital caliper was used to measure dental arch widths. Changes in the rotation of the maxillary molars were analyzed using “occlu-sograms”, which were printed from photographs of the occlusal aspect of the study model. Results: The maxillary teeth interacted with one another in the alveolar bone, resulting in progressive mesial tipping of the posterior teeth before orthodontic treatment. After orthodontic treatment, the angle relative to the FOP exhibited a significant increase, indicating that the maxillary teeth underwent distally directed uprighting (P < 0.05). The upper and lower dentitions exhibited a considerable increase in dental arch width after treatment (P < 0.01). Meanwhile, the rotation of the posterior teeth did not exhibit any significant changes. Conclusions: Based on the results, both uprighting of mesially tipped lateral teeth and expansion of narrow dental arches could prove to be keys to success in space regaining or correction of high canines and mild crowding.

High Canine, Posterior Teeth, Crown Angulation, Functional Occlusal Plane

Masunaga, M. , Ueda, H. , Shibaguchi, T. and Tanne, K. (2019) Mesially Directed Inclination of Posterior Teeth Contributing to Maxillary High Canine, and Changes during Orthodontic Treatment. Open Journal of Stomatology, 9, 64-74. doi: 10.4236/ojst.2019.93007.