To evaluate (1) gingival zenith (GZ) of bilateral agenesis of maxillary lateral incisors treated either with tooth recontouring or implants, (2) the relationship between GZ as an aesthetic principle and smile attractiveness by laypersons.
Method:
Forty-two patients were split into three groups: space closure and tooth recontouring (TR, n=18), tooth implant (TI, n=10), controls with no treatment and no agenesis (CG, n=24). Patients’ plaster study models were scanned (Scanner R250 - 3Shape) and their images analyzed with the Software OrthoAnalyser (3Shape). GZ was evaluated via a line connecting the zenith of the central incisor to the zenith of the canine, towards the right and left sides of the smile. Specific GZ of the lateral incisor was measured by the difference between this line and the zenith of the lateral incisor in mm. Measures were taken twice by a single examiner with a 15-day interval. For aesthetic perception analysis, intraoral photos were randomly arranged in a video (Windows MovieMaker, Microsoft Corporation), shown twice to 30 laypersons (15 men, 15 women), and evaluated through a 5-point attractiveness scale. Statistical analyses were run with the Software R 2.10.1 (p˂0.05).
Result:
Positive correlation was found for within-observer measurements of the study models (Spearman Correlation, r=0,96). Significant differences were found for GZ measures on the left side between TR and CG (Kruskal-Wallis, p=.016). Negative Measures were found in TR on the right side (x̅ =-0.83) and left (x̅=-0.15), which indicates formation of gingival inverted triangles. As for aesthetic perception, the two laypersons’ analyses showed no significant differences (Wilcoxon Signed Rank, p=0.086). Similarly, no differences were found concerning different genders’ evaluations (p=0.261), and attractiveness perception regarding type of treatment (p=0.107) by Multinomial Logit Model.
Conclusion:
Although GZ measures in the TR showed more variation, they did not influence the perception of smile attractiveness by laypersons.