Wilson maxillary curve analyzed by CBCT. A study on normocclusion and malocclusion individuals

Abstract

The anatomy of dental compensation curve in the frontal plane described by George H. Wilson is one of the occlusal determinants of orthodontic treatment. However, there is few published comparing malocclusion and normocclusion individuals. Objectives: The aim of this study is to compare the curve of Wilson at first and second maxillary molars, normocclusion pattern and malocclusion pattern, with and without bilateral posterior crossbite, using angular references in CBCT studies. Material and Methods: We analyzed 10 cases of malocclusion with bilateral posterior crossbite, 10 cases of malocclusion without bilateral posterior crossbite and 10 cases with non orthodontic normocclusion (patients who underwent cone beam study for other reasons than orthodontic). All of them were adults, more than 19 years. Angular variables from left and right axis (line connecting the occlusal and furcation groove) of first and second molars towards a perpendicular to the frontal palate were measured. There was carried out an Anova test, Bonferroni analysis and Levene´s statistics. Results: The descriptive analysis of the results shows an average values of total maxillary curve of Wilson for first molars (sum of left and right angle) of 8.1° for normocclusion group, 0.4° for the malocclusion pattern with bilateral posterior crossbite and 16.9° for the malocclusion pattern without this alteration. The mean differences was statistical significant (P<0,042) between between malocclusion pattern groups with and without crossbite . Conclusion: The curve of Wilson, measured at maxillary first molars in patients with bilateral posterior crossbite is more concave than the other groups, suggesting no dentoalveolar compensations. Key words:Wilson curve, CBCT, buccal posterior occlusion, posterior crossbite.

Buccolingual inclination of molars in untreated children and adults: A cone beam computed tomography study

“…The results illustrated that the maxillary and mandibular molars were more upright in adults than in children, which was in support of the findings of Marshall et al 5 and Sayania et al 6 It is important to know that at the adult age, normally the maxillary molars still exhibited some buccal inclination, and mandibular molars still exhibited some lingual inclination, which was in agreement with the findings of Berrera et al 10 and Alkhatib and Chung. 11 Weinstein et al 16 reported that each unit of the dentition was in equilibrium with its surroundings at any instant.…”

“…Determining the tooth axis for the upper molars poses specific challenges due to the frequent divergence between the upper molar roots. Barrera et al 10 used a line connecting the central groove to the furcation for the molar axis, which was similar to the method used in this study. Kasai and Kawamura 11 defined the long axis to pass through the mid-point at one-half of the crown width and the mid-point at one-third of the distance from the root apex.…”

“…Barrera et al 10 investigated the inclination of maxillary first molars in adults using CBCT. Of the 10 normocclusion adults they evaluated, the average buccal inclination was 4.058 per side; of the 10 malocclusion adults with bilateral posterior crossbite, the average buccal inclination was only 0.28.…”

Evaluation of the Relationship between Curve of Spee, WALA-FA Distance and Curve of Wilson in Normal Occlusion

“…In the present study, the depth of COS was obtained for each tooth and by measuring the perpendicular distance from the cusp tips to the ROP. In the literature, apart from the investigations that measure CW by directly determining the axial inclination of the teeth in CBCT images (9), there were also measurements published in which the investigators create lines passing the buccal and lingual cusps of the teeth on the models, thereby removing the need for radiation. Similarly, the angle made by the line passing the cusp tips with the reference plane was measured in this study.…”

“…On the frontal plane, the occlusal table passing the cusp tips of the posterior teeth does not follow the same plane. Wilson described this as a compensational curve to prevent balancing interferences (9). This curve, specified by Andrews as the fourth key of the ideal occlusion, is given form by the buccolingual inclinations of the posterior teeth (10).…”