• Nadda Manoonsin, D.D.S.
• Paiboon Techalertpaisarn, D.D.S., Ph.D.

Background/objectives To evaluate the attractiveness of smile arcs obtained by different vertical
bracket positions and occlusal plane angles (OPAs).

Materials and methods Three dental models represented tooth position after leveling with three
bracket positions: a conventional bracket position (Con) according to a guideline based on tooth
measurement, and bracket positions resulted in extruding (Ext) or intruding (Int) the maxillary
incisors. Photographs of the three models were taken at OPAs of 5, 10, and 15° to the true horizontal.
The photographs were digitally morphed onto a posed female smile. Nine smile arc photographs were
obtained and assessed by a group of orthodontists, dentists, and laypeople.

Results At an average OPA (10°), the Con10 image received a significantly higher esthetic score
compared with the Ext10 and Int10 images. The Ext group smile attractiveness significantly decreased
from an OPA of 5° (Ext5 image) to 10° (Ext10 image), while the attractiveness of the Int group
significantly increased with increasing OPAs.

Conclusions Vertical bracket position and OPA affected smile arc esthetic perception. At an average
OPA, the smile arc obtained by bracket position based on tooth measurement resulted in the most
attractive smile arc compared with that obtained by bracket positions resulted in extruding or intruding
the maxillary incisors. Extruding the maxillary incisors may be beneficial to those with a low OPA,
while intruding the maxillary incisors may be done in patients with a high OPA without showing a flat
or reversed smile arc.

(CU Dent J. 2017;40:51-62)