Artificial Intelligence (AI) Empowered Smile Simulations: Do They Accurately Predict Actual Post Treatment Outcomes

Primary outcomes

1. Smile line

   Time frame: through study completion, an average of 1 year

   The extent of the vertical tooth display on smiling or the elevation of the upper lip in relation to the maxillary incisors. Three types of smile lines have been described- high, average, and low. A high smile shows the maxillary anterior teeth along with a significant amount of gingiva, an average smile shows maxillary anterior teeth with only interproximal gingiva, and a low smile typically shows less than two-thirds of the maxillary anterior teeth

2. Smile arc

   Time frame: through study completion, an average of 1 year

   The relationship between the curvature of the maxillary anterior teeth and upper border of the lower lip. It is defined by drawing a line along the maxillary central incisal edges to the cusp tips of maxillary canines, which is related to another line drawn across the superior border of the lower lip. In subjects whose maxillary teeth are covered by lower lip, smile arc is designated as "not available". Three types of smile arcs have been described- "parallel to the teeth" (when the two lines follow the same curvature) also called a consonant smile, and a non-consonant smile, if the two lines are not parallel. A non-consonant smile can either be "straight" (with flatter curvature of the maxillary anterior teeth in relation to the lower lip) or "reverse" (when the maxillary anterior teeth form a reverse curve in relation to lower lip).

3. The most posterior teeth displayed

   Time frame: through study completion, an average of 1 year

   Smiles are categorized as displaying teeth up to the canines, first premolars, second premolars, or the first molars. A tooth is counted when more than half of its surface is visible.

4. The philtrum height

   Time frame: through study completion, an average of 1 year

   Distance measured in millimeters from subspinale (the base of the nose at the midline) to the most inferior portion of the upper lip on the vermilion tip beneath the philtral columns

5. Commissure height

   Time frame: through study completion, an average of 1 year

   Distance measured in millimeters from a line constructed from the alar bases through subspinale and then from the commissures perpendicular to this line. The differential lip growth exhibits the difference in height in philtrum and commissural height in adolescents.

6. Smile width/Inter-commissure width

   Time frame: through study completion, an average of 1 year

   The distance (mm) from outer commissure to outer commissure on smile in millimeters.

7. Smile index

   Time frame: through study completion, an average of 1 year

   The ratio between the horizontal smile width and the vertical smile height during smiling (smile width/smile height).

8. Maxillary inter-canine width

   Time frame: through study completion, an average of 1 year

   distance from the distal aspect of the right canine to the distal aspect of the left canine in millimeters

9. Buccal corridor

   Time frame: through study completion, an average of 1 year

   It is the space created between the buccal surface of the posterior teeth and the lip corners when the patient smiles. Orthodontists often refer to buccal corridors as "negative spaces". The buccal corridor is measured from the mesial line angle of the maxillary first premolars to the interior portion of the commissure of the lips. Moore et al [16]. have previously quantified a buccal corridor of 28% as medium-narrow, 15% as medium, 10% as medium-broad, and 2% as broad smile fullness

10. Amount of lower incisor show

    Time frame: through study completion, an average of 1 year

    The amount of lower incisor display which can be categorized into either 1) No show of lower incisors during smiling, 2) partial lower incisor exposure or 3) full length lower incisor exposure.