Buccolingual Inclination of Second Molars in Untreated Adolescents and Adults with Near Normal Occlusion: A CBCT Study

Abstract

The mandibular second molars are lingually positioned relative to the alveolar ridge and have a limited amount of lingual alveolar bony support. As the maxillary second molars are articulated with the mandibular second molars, maintaining the normal buccolingual inclination of both maxillary and mandibular second molars would potentially help to not only optimize the masticatory function, but also avoid dehiscence and fenestration. The current study evaluated the buccolingual inclination of second molars in untreated adolescents and adults. One hundred and two Caucasian subjects with skeletal class I and minimum dental arch crowding/spacing were selected and divided into two groups: (1) adolescent group: age 12–18 years, N = 51 (21 females, 30 males); (2) adult group: age 19–65 years, N = 51 (40 females, 11 males). For each subject, the inclination for each second molar was measured as the angle between the long axis of each tooth and a vertical line on cone beam computed tomography images. The Mann–Whitney U test was used for intergroup comparisons. Maxillary second molars exhibited a buccal inclination of 15.30° in the adolescent group and 15.70° in the adult group. Mandibular second molars exhibited a lingual inclination of 17.05° in the adolescent group and 15.20° in the adult group. No statistically significant differences were detected between the age groups. In addition, a statistically significant difference was only found between genders in the adolescent group for the maxillary second molar inclination. In summary, maxillary second molars exhibited buccal inclination and mandibular second molars exhibited lingual inclination. The amount of buccolingual inclination of the second molars was similar in the adolescent and adult groups.

Correlation between Tooth Position Parameters and Apical Fenestration: A Cone-Beam Computed Tomography Study

“…More recently, in a CBCT study including adolescent and adult patients, it was found in all patients that the maxillary second molar showed buccal inclination, and the mandibular second molar showed lingual inclination [25]. These findings provide a rationale for the occurrence of lingual fenestrations in the lower teeth as identified in the current study.…”

Evaluation of Buccolingual Inclinations of First Molars Among Different Vertical Facial Patterns in Class II Division I Subjects

“…Wilson's curve is the name given to this occlusal curve in the coronal plane [ 6 ]. The natural curvature of the teeth is thought to allow the posterior teeth inclination to line up with the orientation and inward pull of the medial pterygoid muscle during contraction [ 7 ]. This provides optimal resistance to masticatory forces, facilitates access to food for efficient chewing, and ensures effective cuspal contact engagement [ 8 , 9 ].…”

“…Numerous research investigations addressing the inclinations of the posterior teeth have frequently divided their participants into groups based on sagittal [ 1 , 10 - 12 ] or vertical [ 2 , 13 - 17 ] skeletal features. Conversely, certain studies have examined inclinations without explicitly determining sagittal or vertical classification [ 5 - 7 , 18 , 19 ]. The majority of earlier studies have only used model casts to evaluate buccolingual inclination based on tooth crowns [ 1 , 10 - 13 , 18 ].…”

“…Hence, researchers sought the development of novel methods that would enable the visualization of both crown and root structures for an accurate assessment of tooth inclination. The development of three-dimensional imaging methods, including computed tomography (CT) and cone beam computed tomography (CBCT), allowed for the fulfillment of this requirement, which empowers practitioners to visualize and measure the true inclination of teeth [ 2 , 4 - 7 , 14 - 17 , 19 , 20 ].…”