The effect of axial midline angulation on dental esthetics

The purpose of this study was to analyze the effect of various degrees of axial midline angulation on the attractiveness of a smile. We explored the influence of age, race, sex, direction of midline deviation, education, occupation, and dominant hand on each evaluator's perception of dental esthetics. Photographs of smiling subjects--one man and one woman--were altered to produce both left and right axial midline angulations in 5 degree increments. Fifty orthodontists and 50 laypeople evaluated these altered photographs by assigning both a numerical attractiveness rating and an acceptable or unacceptable rating to each. The results showed that attractiveness scores and acceptability ratings declined consistently as axial midline angulation increased. Statistical analysis showed that both sex of the subject and occupation of the judge were significant variables (P < .05) in the evaluation of the subjects. Age, race, sex of the judge, education level, direction of midline deviation, and dominant hand were not statistically significant. The mean acceptable midline angulation for the male subject was 6.6 +/- 4.5 degrees for orthodontists and 10.7 +/- 6.2 degrees for laypeople. For the female subject, the mean acceptable threshold was 6.4 +/- 4.0 degrees for orthodontists and 10.0 +/- 6.1 degrees for laypeople (P < .001). Discrepancies of 10 degrees were unacceptable by 68% of orthodontists and 41% of laypeople.