Intraobserver reliability of the 2-dimensional analysis of facial expressions

Changes in facial expressions following functional orthopaedic treatment for Class II division 1 malocclusion: a prospective controlled study

OBJECTIVE

The aim of this study was to quantify changes in facial expressions in children with Class II division 1 malocclusion treated with functional appliances.

MATERIALS AND METHODS

A prospective controlled study was carried out evaluating 20 children with Class II division 1 malocclusion (ages 9-13) treated with a functional appliance for 12 months (treatment group). Age- and gender-matched children without immediate orthodontic treatment need were followed up without treatment for 12 months (control group). A frame-mode video sequence was taken of each subject at the beginning and end of the 12-month study period, during which 5 distinct facial expressions (posed smile, spontaneous smile, aggressive smile, lip pucker, and maximal mouth opening) were recorded. Frames at which each facial expression was at its peak were analysed. Changes in horizontal and vertical facial anthropometric distances brought about by performing each facial expression were measured. Intragroup differences following treatment were assessed using paired t-tests, whereas intergroup differences were assessed using unpaired t-tests.

RESULTS

All treated children showed an improvement in dentoalveolar relationships. Initial facial expressions differed between groups, with the treatment group showing less marked changes during lip pucker and more marked changes during maximal mouth opening. In contrast, no statistically significant differences were found between groups for the final facial expressions.

CONCLUSIONS

This study suggests that functional appliance use in growing children with Class II division 1 malocclusion tends to normalize soft-tissue movements during facial expressions.

Class II functional appliance treatment and dynamic three-dimensional mimic muscle evaluation

BACKGROUND

Functional appliances have skeletal and dentoalveolar treatment effects, but knowledge on their effect on facial expressions is limited.

OBJECTIVE

To analyse changes in facial expressions, using three-dimensional (3D) mimic muscle evaluation, in growing children with Class II malocclusion and large overjet, undergoing functional appliance treatment.

METHODS

Fifteen growing children with Class II division 1 malocclusion, selected prospectively, had dynamic 3D recordings of facial expressions prior to and 12 months after commencing functional appliance treatment. Facial expressions recorded were smile and lip pucker, and the movements of the oral commissures were analysed, as well as mouth width and its symmetry. A control group of fifteen age- and sex-matched growing children without immediate need for orthodontic treatment had similar recordings prior to and after a 12-month observation period.

RESULTS

In the treatment group, the Class II malocclusion in all children improved after 12 months of functional appliance wear. With regard to movements of the oral commissures, the initial recordings of the treatment group did not show any significant differences to the control group for neither smile nor lip pucker. Differences were noted however when looking at mouth width asymmetry, where this tended to become more symmetrical in the functional appliance treatment group, during rest and during smiling, while it became more asymmetrical in the untreated control group.

CONCLUSION

The use of removable functional appliances in children with Class II division 1 malocclusion may have a positive effect on mouth width symmetry when smiling, making it more symmetrical.

Perception of Smile Esthetics by Orthodontists and Laypersons: Full Face and A Localized View of The Social and Spontaneous Smiles

Objective

The aim of the study was to evaluate the parameters that might affect the esthetic perception of localized and full-face views of social and spontaneous smiles.

Methods

Video records of 40 individuals were used. Further, 200 images of each individual were captured for social and spontaneous smiles with and without calibration glasses. Full-face images of social smile (SSF) and spontaneous smile (smile of joy) (JSF) were obtained. Furthermore, the mouth-area images of the same social (SSM) and spontaneous (JSM) smiles from each subject were acquired. Here 160 images were evaluated by orthodontists and laypersons using the Q-sort method. The data were analyzed with logistic regression and independent samples t-test.

Results

From the orthodontic perspective, upper lip thickness (p=0.004), lip curtain over incisors (p=0.016), maxillary incisor display (p=0.01), and buccal corridor ratio (p=0.006) were significant to determine attractive and unattractive images when viewing localized social smiles. Laypersons identified no particular parameter to explain the variation in preferences for all the image groups (p>0.05).

Conclusion

Upper lip thickness and maxillary incisor display during smiling were found to be effective for distinguishing images as attractive and unattractive by orthodontists. No objective evaluations for the attractiveness were made by laypersons.