An orthodontic analysis of the smile dynamics with videography

Smile is one of the most effective means by which people convey their emotions. The objective of this study was to capture, analyse and measure the parameters through videos clips for studying the dynamics of posed and unposed smile and to measure the parameters through video clips for studying the dynamics of speech.

A total of 100 subjects seeking orthodontic treatment with Angle's Class I malocclusion were included in the study. The principal investigator selected the frames for speech and a panel of five members selected the appropriate frames for posed smile and unposed smiles. Frames after videography were used for measurements. Parameters like Maximum incisor exposure, Lower lip to upper incisor, Gingival exposure, Inter-labial gap etc were measured in "mm" for posed and unposed smile frames. Categorical data was compared using McNemar's test. p ​< ​0.05 was considered significant.

The median of maximum upper incisal exposure (p ​= ​2.2e-16), lower lip to upper incisor (p ​= ​2.422e-13^A), inter-labial gap (p ​= ​2.2e-16 ^A), smile width (p ​= ​5.212e-16 ^A) and smile index were significant (p ​= ​0.0001 ^A). There was a significant change from not exposed to exposed gingival exposure over posed smile to unposed smile (p ​= ​0.0008). The most posterior maxillary tooth visible in the posed and unposed groups were the second premolars in 57% and 74% patients, respectively. In both the smile groups, 55% of subjects exhibited a consonant smile.

It can be concluded that the information obtained from the current video graphic study can be used as a guideline for the diagnosis and as a part of comprehensive treatment planning.