Layperson's preference of the transverse occlusal plane in asymmetric facial model

Abstract

Objective Facial asymmetries are common, especially deviated nose and chin. The clinician must consider these variables when establishing the smile, placement and angulation of the occlusal plane. The purpose of this article is to determine if nose and chin deviations affect the perception of laypeople towards different angulations of the occlusal plane cant. Materials and Method An asymmetric facial model was created from a symmetric facial model used in a previous study. Nose and chin were deviated 3 mm to the left and eight different pictures were created, each with different degrees of occlusal plane cant in both direction. Using a visual Likert scale delivered via Websurvey within the private practice setting, 120 randomly selected laypersons evaluated each image according to their own beauty preferences. Results In an asymmetric face, nose and chin deviated 3 mm to the left, a minor occlusal plane angulation of 2° can be perceptible regardless of the direction of the cant. Conclusions The occlusal plane should be as parallel to the interpupillary line as possible. If occlusal cant is present, less than 2° of angulation it is preferable, regardless of the direction of the nose and chin. Clinical Significance In the presence of an asymmetric face, the occlusal plane should be as parallel as possible to the interpupillary line. The direction of the deviation of the nose and the chin are irrelevant factors to determine the occlusal plane. An inclination of the occlusal plane can cause vertical discrepancy, which could subsequently create malocclusion. A complete dentofacial analysis can aim at assessing the angulation of the occlusal plane not only for esthetic outcomes, but for also allowing correct occlusal function.

Aesthetic Preference in the Transverse Orientation of the Occlusal Plane in Rehabilitation: Perspective of Laypeople and Dentists

“…The age of each group was not a factor that affected the perception of attractiveness, since when comparing each pair of images, the age ranges of each group did not differ significantly in their responses. This result is in agreement with what Silva et al stated when analyzing the perception of laypeople facing OP inclinations along with nose and chin deviations [12]. The opposite was found by Revilla-León et al since, on a scale from 1 to 6, for the classification of the OP inclination, older people (laypeople, dentist and dental students) tended to give higher ratings, that is, to consider images more attractive than the younger participants did [1].…”

“…In general, sex was not a factor that affected the perception of attractiveness of each of the groups, which is similarly to the results obtained in the study by Jiménez-Castellanos et al (for laypeople), in the study by Silva et al in [1,12,19,33]. The only exception regarding the participant's sex occurred in the case of lay women, who significantly preferred the OP parallel to the IL than with a mean between the IL and the CL equivalent to 1.5 degrees, while lay men had no significant results that could declare the existence of some preference.…”

“…In order to maintain facial harmony in the transverse analysis of the OP, from a frontal perspective, it is known that it must be perpendicular to the facial midline and parallel to the horizontal facial reference lines, such as the interpupillary line (IL) and the line of the labial commissures (CL) [12,13].…”

“…Currently, the scientific literature disagrees as to which horizontal reference to use in framing the OP in the facial context, and there is also a need to determine within what limits are visually accepted discrepancies in the transverse plane. Thus, the need for further studies to help clarify the dentists' decision-making process during the rehabilitative diagnosis process is urged [1,12,13,20].…”

A Comparative Study on the Perception of Dental Esthetics of Laypersons and Dental Students

“…Most of them involve digitally modified images that change several parameters of the smile aesthetics. (2)(3)(4) In a study where 96 subjects (dentists, dental technicians and laypersons) analyzed the ideal proportion of the maxillary central incisor, a preference for 82% ratio has been reported. Extreme values have been unanimously been considered non-aesthetic.…”