Canting of the occlusal plane: Perceptions of dental professionals and laypersons

Objectives: To determine if canting of the occlusal plane influences esthetic evaluation of the smile among orthodontists, dentists and laypersons. Study Design: A frontal photo of a smile with 0 degrees occlusal plane canting in relation to the bipupillary plane was modified using Adobe Photoshop C3 (Adobe Systems Inc, San Jose, California) to generate two images with occlusal plane inclinations of 2 degrees and 4 degrees. The three images were evaluated esthetically by orthodontists (n=40) general dentists (n=40) and laypersons (n=40). Each image was awarded a score as follows: 1=esthetically acceptable; 2=moderately acceptable; 3=esthetically unacceptable. Evaluators also placed the three images in order in preference. Data were analyzed using the Kruskal-Wallis (p<0.05) and the Mann-Whitney tests, applying the Bonferroni Correction (p<0.016). Results: No significant differences (p>0.05) were found between the three groups for 0 degrees and 2 degrees cants (median for orthodontists=1; general dentists=1; laypersons=1). Orthodontists (median score=3) made evaluations of the image with 4 degrees occlusal plane that were significantly different from general dentists (median=2) and laypersons (median=2). All three groups put the 0 degrees image in first place in order of esthetic acceptability, the 2 degrees image in second place and the 4 degrees image in third place. Orthodontists placed the 0 degrees image in first place with significantly greater frequency (p<0.016) than laypersons. Conclusions: Occlusal plane canting of 0 degrees and 2 degrees were evaluated as esthetically acceptable by the three groups. The 4 degrees occlusal plane cant was evaluated more negatively by orthodontists than by general dentists and laypersons. All three groups placed the 0 degrees image in first place of esthetic acceptability, 2 degrees in second place and 4 degrees in third. Orthodontists put the 0 degrees image in first place with significantly greater frequency than laypersons.