Reproducibility of a method for analysis of morphological changes in perioral soft tissue in children using video cameras

The Ability to Sustain Facial Expressions

To gain more insight into facial muscle function, imaging during action would be optimal. Magnetic resonance imaging is highly suitable for visualizing facial muscles. However, magnetic resonance imaging requires the individual to remain as still as possible for a while. Knowledge of the ability to sustain facial expressions is requisite before scanning individuals. This could help adapting the scanning protocol to obtain optimal quality of imaging the muscles in action. A study, including 10 healthy volunteers, was done to perceive the extent of movement while holding facial expressions of smiling and pouting. During 6 minutes, 3-dimensional photographs were taken every consecutive minute while the participants maintained their facial expressions as motionless as possible. The movement was objectified by creating distance maps between the 2 models and calculating the Root Mean Square using the software 3DMedX. The results showed that most movements occurred in the first minute, with a decrease of the intensity of the expression. After the first minute, the expression, although less intense, could be held stable. This implies that magnetic resonance imaging scanning during facial expression is possible, provided that the scanning starts after the first minute has elapsed. In addition, results demonstrated that more slackening of the muscles while smiling compared with pouting.

The Average Facial Expressions: A Range of Motion Analysis for Different Sex and Age Groups

Facial expressions are ubiquitous in communication. Therefore, assessment of mimic function is essential in facial surgery, but no reference standards are currently available. This prospective study aims to create reference values of three-dimensional landmark displacement for different sex and age groups.

Methods

Three-dimensional photographs were taken from healthy subjects in rest, maximum closed smile, and pouting. Displacement for both exercises of perioral landmarks was analyzed with MATLAB as absolute displacement and as the ratio of mouth width. Additionally, displacement in three planes was analyzed for each landmark. Averages were calculated for both genders in four age groups: 4-8, 8-12, 12-16, and >16 years.

Results

In total, 328 subjects were included. Oral landmarks predominantly moved forward and backward for both exercises. Nasal landmarks predominantly moved vertically. Growing up, oral landmark displacement decreased for smiling, whereas nasal landmark displacement increased. For pouting, oral landmark displacement increased while growing up, whereas nasal landmark displacement decreased.

Conclusions

The present study creates reference values for movement of perioral structures for different sex and age groups, for two facial expressions. These data are of great value for the assessment of mimic function and give insight into the development of facial animation over time.

Creating Three-Dimensional Templates of Smiling and Pouting Faces for Different Sex- and Age Groups

Smile appearance has a major psychological impact. Orthognathic surgery, which has harmonizing results on skeletal structures, can negatively influence the smile appearance due to soft tissue effects. To enhance the aesthetic effects of orthognathic surgery on soft tissues, reference models for large parts of the hospital’s adherent area are called for. This study aims to create average facial models for different sex and age groups in two facial exercises: maximum closed smile, and pouting. These models were created using coherent point drift and Procrustes algorithms in MATLAB. Principal component analysis was performed, and of 20 surgical landmarks, the in-group variation using standard deviation was calculated. Three distances were analyzed: nasal width, philtral width, and mouth width. To correct for facial size, these distances were analyzed as a ratio of intercanthal width. In total, 328 healthy subjects were included in the study. Subjects were grouped by sex, and in age categories spanning four years each, with an adult group with all ages >16 years. For both smiling and pouting faces, all ratios increased with ageing. These templates and data can benefit facial surgeons, to obtain an expected outcome according to the age of the patient.

Changes in Soft Tissue Profile After Orthodontic Treatment With and Without Extraction: A Systematic Review and Meta-analysis

OBJECTIVE

The objective of this systematic review and meta-analysis was to evaluate the soft tissue changes in adult orthodontic patients who received extraction treatment in comparison to their counterparts who received nonextraction orthodontic treatment.

METHODS

Electronic databases (CENTRAL-Cochrane Register of Controlled Trials, PubMed, Embase, EBESCOhost, LILACS, and Google Scholar) were searched up to March 2015. Handsearching was performed too. The selection process included controlled trials (prospective or retrospective and randomized or nonrandomized) on adult patients receiving orthodontic extraction treatment compared within the same study to a group treated without extraction. The outcomes of interest were the changes in linear and angular cephalometric measurements specific for soft tissue profile. Studies which fulfilled the selection criteria were retrieved. They were assessed for methodological quality based on a validated checklist. Studies of moderate to high quality were included.

RESULTS

Of the nine full texts which fulfilled the selection criteria, 5 were eligible for the quantitative analysis; they scored a moderate quality. Meta-analysis showed a significant increase regarding the nasolabial angle, upper lip thickness, labrale superioris to E-Line, and labrale inferioris to E-line in the extraction group, suggesting the flattening of the profile following extraction treatment.

CONCLUSION

A significant retraction of the lips and an increase in the nasolabial angle are associated with extraction protocols, but the degree to which these changes are considered detrimental/beneficial to the profile could be affected by different factors. Since these finding are based on studies of moderate quality, future research with well-conducted methodologies are highly recommended.

Dynamics of a smile in different age groups

OBJECTIVE

To evaluate smile in different age groups and to detect gender differences in smile.

MATERIALS AND METHODS

Digital videographic records of 241 randomly selected subjects were obtained for smile analysis. The subjects were divided into four groups by age (15-20 years, 21-30 years, 31-40 years, and 41-50 years). Each group was further subdivided by gender. After 41 subjects were excluded, the smile dimensions of 200 subjects were analyzed by two-way multivariate analysis of variance (MANOVA) with Duncan's multiple range post hoc test.

RESULTS

All dynamic measurements (change in upper lip length, upper lip thickness, commissure height, and intercommissural width from rest to smile) decreased with age in both males and females. Changes in upper lip length and commissure height on smiling were greater in males as compared with females of the same age groups. Changes in intercommissural width on smiling were greater in females as compared with males in all age groups.

CONCLUSION

Smile changes with increase in age, and the changes differ between males and females. Females had a wider smile as compared with males of similar age groups.

Exploring quantitative methods for evaluation of lip function

The objective was to explore quantitative methods for the measurement of lip mobility and lip force and to relate these to qualitative assessments of lip function. Fifty healthy adults (mean age 45 years) and 23 adults with diagnoses affecting the facial muscles (mean age 37 years) participated in the study. Diagnoses were Möbius syndrome (n=5), Facioscapulohumeral muscular dystrophy (n=6) and Myotonic dystrophy type 1 (n=12). A system for computerised 3D analysis of lip mobility and a lip force meter were tested, and the results were related to results from qualitative assessments of lip mobility, speech (articulation), eating ability and saliva control. Facial expressions studied were open mouth smile and lip pucker. Normative data and cut-off values for adults on lip mobility and lip force were proposed, and the diagnostic value of these thresholds was tested. The proposed cut-off values could identify all inviduals with moderate or severe impairment of lip mobility but not always the milder cases. There were significant correlations between the results from quantitative measurements and qualitative assessments. The examined instruments for measuring lip function were found to be reliable with an acceptable measuring error. The combination of quantitative and qualitative ways to evaluate lip function made it possible to show the strong relation between lip contraction, lip force, eating ability and saliva control. The same combination of assessments can be used in the future to study if oral motor exercises aimed at improving lip mobility and strength could have a positive effect on lip function.

The effect of lip strengthening exercises in children and adolescents with myotonic dystrophy type 1

OBJECTIVE

Myotonic dystrophy type 1 (DM1) is a slowly progressive neuromuscular disease. Most children and adolescents with DM1 have weak lips and impaired lip function. The primary aim of the present study was to investigate if regular training with an oral screen could strengthen the lip muscles in children and adolescents with DM1. If lip strength improved, a secondary aim would be to see if this could have an immediate effect on lip functions such as lip mobility, eating and drinking ability, saliva control, and lip articulation.

METHODS

Eight school aged children and adolescents (7-19 years) with DM1 were enrolled in an intervention study with a single group counterbalanced design. After three baseline measurements four children (Subgroup A) were randomly chosen to start 16 weeks therapy while the others (Subgroup B) acted as controls without therapy. After 16 weeks the subgroups changed roles. During treatment the participants exercised lip strength with an oral screen for 16 min, 5 days/week. Lip force, grip force (control variable), and lip articulation were followed-up every fourth week. At baseline, after treatment, and after maintenance, the assessment protocol was completed with measurements of lip mobility using 3D motion analysis and parental reports concerning eating ability and saliva control.

RESULTS

Seven of eight participants improved maximal lip strength and endurance but only four showed significant change. Increased lip strength did not automatically lead to improved function. There was a wide intra-individual variation concerning speech and eating ability within and between assessments. The treatment programme could be carried out without major problems but the frequency and the effect of training were affected by recurrent infections in some.

CONCLUSIONS

Maximal lip force and lip force endurance can improve in school aged children and adolescents with DM1. Improved lip strength alone cannot be expected to have an effect on lip articulation, saliva control, or eating and drinking ability in this population. Lip strengthening exercises can be a complement but not a replacement for speech therapy and dysphagia treatment. A prefabricated oral screen is an easy to use tool suitable for strengthening lip exercises.

Intraobserver reliability of the 2-dimensional analysis of facial expressions

PURPOSE

The aim of our study was to develop a reliable method to identify certain facial expressions of the lower face that are easy to re-create through proper instruction and with high reproducibility. We wanted to quantitatively evaluate facial expressions in a simple, efficient, and inexpensive manner that is easily applicable in many clinical settings and in a wide variety of patients.

MATERIALS AND METHODS

We included 40 healthy subjects (20 women [mean age, 25.6 years] and 20 men [mean age, 27.0 years]). A digital camcorder recorded a video sequence (video 1) where the subject was verbally asked to execute several facial expressions (posed smile, spontaneous smile, aggressive smile, lip pucker, and maximum opening). Two weeks later, the video session was repeated (video 2). Frames of each expression were selected from the digitized video sequences. Horizontal and vertical distances were measured in each selected frame.

RESULTS

We found no statistically significant differences between the 2 videos of the expressions studied (except vertical lip changes for posed smile, lip pucker, and maximum mouth opening expression). The calculated coefficient of reliability was high and varied between 0.994 and 0.996, which confirms the reliability of the method.

CONCLUSION

This 2-dimensional method is an accurate means to quantitatively evaluate facial expressions in a simple, efficient, and inexpensive manner. The lip pucker, posed smile, spontaneous smile, and aggressive smile were the best and most reproducible expressions of the chosen expressions in this study.

Lip morphological changes in orthodontic treatment. Class II division 1: malocclusion and normal occlusion at rest and on smiling

OBJECTIVE

To evaluate the morphological changes in the lips and to determine the degree of improvement in the smile after orthodontic treatment for Class II division 1 malocclusion.

MATERIALS AND METHODS

The sample subjects were divided into two groups: a group that consisted of 20 adult female patients with Angle Class II division 1 malocclusion and a control group that consisted of 28 adult female volunteers with normal occlusion. Frontal photographs were taken before and after orthodontic treatment, and 35 landmarks were placed on each tracing made from the photograph. Thereafter, landmarks were digitized into an x- and y-coordinate system with the subnasal point as the origin. The comparisons between pretreatment and posttreatment at rest and on smiling, and the comparisons between Class II division 1 and control group were made using Student's t-test.

RESULTS

Both the upper and lower lips in the smile of patients in the Class II division 1 pretreatment group were positioned downward, and the upward movement of the upper lip and mouth corners was smaller in comparison with the control group. These characteristics of the Class II smile improved after orthodontic treatment, but the differences with the control group remained unchanged immediately after treatment.

CONCLUSION

The soft tissue morphology shows a relative improvement after orthodontic treatment.

Gender and age differences in facial expressions

The aim of this research was to determine a reliable method for quantitatively evaluating the facial expressions of children and adults in order to assess their dependence on age and gender. This study evaluated 80 healthy subjects divided into four groups: 20 girls (mean age 10.6 years), 20 boys (mean age 10.8 years), 20 females (average age 25.6 years), and 20 males (average age 27.0 years). A video was used to record each individual executing three facial expressions: a rest pose, a lip pucker, and a posed smile. Representative video frames were chosen for each individual's expressions; they were digitized and then analysed with software that extracted a set of horizontal and vertical distances of the face. All distances measured in the posed smile and lip pucker were expressed as a percentage change from the rest pose. Statistical analysis with a two-way multivariate analysis of variance (MANOVA) was performed, with gender and age as the independent variables. It was evident that the ability to produce certain facial expressions differs between groups of individuals due to gender and age. Males had a greater upward vertical movement capacity in the studied facial expressions than females. Females had a more pronounced horizontal component in the posed smile. There was a trend from childhood to adulthood showing an increase in the percentage change in most vertical movements. This trend was present in both genders, though more pronounced in males. Using a robust quantitative method for collecting and analysing facial expressions, gender differences in adults were detected as well as differences between adults and children. The trend toward increasing vertical movements in adults compared with children suggests the possibility that the mimic musculature is developmentally regulated.