Role of canine vertical position and gingival zenith level on smile aesthetics and qualitative evaluation of perception by orthodontists, general dentists and laypersons: A descriptive cross-sectional study
Authors: Rampuri Sakina , Kale Kinjal , Mirdehghan Nasim , Nene Sahil , Hegde Ashwith , Kalia Ajit 
Published: October 2024

: Our objectives were to verify the impact of alterations in the vertical position of the maxillary canines in smile aesthetic perceptions and to determine whether exposure of the gingival margins directly affects laypersons' and orthodontists' perceptions.

: To evaluate the impact of vertical position and gingival zenith level of maxillary canine on smile esthetics as judged by orthodontists, general dentist and laypersons

: This is a qualitative, descriptive cross-sectional study aimed at studying the role of vertical position and gingival zenith level on the smile esthetic perception. A smiling photograph of a male subject with and without exposing the gingival zeniths was selected, and vertical positions and gingival zenith levels of canine were symmetrically modified in increments of 0.5 mm, creating two sets of 4 new modified images varying from 1.0 mm of intrusion to 1.0 mm of extrusion and 1.0 mm of increasing and decreasing the height with gingival exposure. The total of 15 images were evaluated by 40 orthodontists, 40 general dentists and 40 laypersons, who determined the level of attractiveness of each smile on a visual analog scale.

: Both smile arc ( &#60;0.05) and gingival display amount ( &#60;0.001) had statistically significant influences on the perception of smile attractiveness. Smile attractiveness scores with reference to gingival display amount showed a statistically significant ( &#60;0.001) difference between the rater groups. A significant ( &#60;0.05) interaction between smile arc and gingival display amount was observed. No significant difference were noted with standard smiles and intrusion smiles. Also, with 0.5mm extrusion and intrusion images in low smile. The intra-evaluator groups showed no significant difference between intrusion and extrusion high as well as low smile images, (value&#60;0.05 for all). significant difference was seen in extrusion and intrusion high smile at 0.5mm and low smile images at 1mm level, extrusion and intrusion low smile images at 0.5mm level, (value&#62;0.05 for all), significantly higher intrusion and extrusion high smile images at 0.5mm level, (-value&#60;0.05 for all). extrusion and intrusion high as well as low smile images at 1mm and 0.5mm levels, (-value&#60;0.05 for all).

: Orthodontists were more critical in their assessments. There were no differences in the esthetic evaluations of smiles with and without gingival margin exposure for both groups of evaluators. For all the three evaluator groups, the most attractive ones were the standard smile and smile with the intrusion of 0.5 in high smile, standard and extrusion of 0.5 mm in the low smile group 0.5 mm of increased gingival zenith level (GZL) as perceived by orthodontists and general dentists, while for laypeople it was the standard smile. The unattractive smiles have extrusion and intrusion of 1mm for all the three evaluator groups 1 mm followed of decreased GZL of canine, for orthodontists and general dentist with 1mm increased. Laypeople, orthodontists scored all the images more critically by giving lesser scores compared to the general dentists and laypeople.