Juvenile Facial Growth and Mimicry: A Preliminary 3D Study

Three-dimensional nasal asymmetry analysis between adolescence and adulthood in postoperative patients with unilateral cleft lip and palate using computed tomography

AIM

To investigate the differences of the nasal soft and hard tissue asymmetry in postoperative patients with unilateral cleft lip and palate (UCLP) between adolescence and adulthood, and to explore the correlation of nasal soft and hard tissue asymmetry.

METHODS

CT data from 47 repaired UCLP patients were included and divided into two groups:1. adolescent group: 23 patients (15 males, 8 females; age: 10-12 years old). 2. adult group: 24 patients (16 males, 8 females; age:18-32 years old). The three-dimensional asymmetry in nasal soft and hard tissues was analyzed. Additionally, the correlation between nasal soft and hard tissue asymmetry was also analyzed.

RESULTS

Both the adolescent group and adult group showed asymmetries in nasal soft and hard tissues. Compared to the adolescent group, the adult group had a significantly increased horizontal asymmetry of nasal soft tissues Sbal (P < 0.05). Furthermore, the sagittal asymmetry of soft tissue Glat (P < 0.05), Sbal (P < 0.001), Sni (P < 0.001) and hard tissue LPA (P < 0.05) also increased significantly. In the adult group, there were more landmarks with a correlation between the asymmetry of nasal hard tissue and soft tissue compared to the adolescent group. There were moderate to strong correlations between nasal hard and soft tissue symmetries in the horizontal and sagittal directions (0.444 < r < 764), but no correlation in the vertical direction in the adult group (P > 0.05).

CONCLUSIONS

The asymmetry of nasal soft and hard tissues in patients with repaired UCLP becomes more apparent in the horizontal and sagittal dimensions from adolescence to adulthood. The correlation between the asymmetry of nasal hard tissue and soft tissue becomes stronger in the horizontal and sagittal dimensions. These factors should be taken into account when performing treatment for repaired UCLP patients in adolescence and adulthood.

The forensic imaging technique of age progression used within missing people cases: The Italian Missing Children association realizing age progression for Missing Child Kenya

The age progression technique allows to update identification photos of individuals who have been missing for years. This method is based on the study of the facial variation and on the dynamics of facial growth. Knowledge about changes in the distribution of facial fat and the tone of the cartilage allows realistic predictions of the facial appearance after many years. Beside these elements, age progression is also supported by similar characters between family members. This is why photos of the missing and family members are used to create an age progression, making the new identikit accurate. Non-profit associations are crucial for the dissemination of information on the problem of missing persons. In Italy, the Italian Missing Children association provides for free an age progression service with the support of forensic anthropology. With the activation of a protocol, consisting of guidelines, and a form for the request for age progression by family members, the Italian Missing Children has started a collaboration with Missing Child Kenya. It allowed to disseminate up-to-date photos of the presumed current appearance of the missing children in Kenya. Thus, in the present study some cases are reported, in which age progression technique was applied. The photos provided by Italian Missing Children were shown in video documentaries made by Missing Child Kenya, allowing to continue the dissemination of age progression photo during the Covid quarantines and to keep the population active in the search for the missing.

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.

Nasal asymmetry changes during growth and development in 6- to 12-year-old children with repaired unilateral cleft lip and palate: A 3D computed tomography analysis

Repaired unilateral cleft lip and palate (UCLP) is often accompanied by the deformity and asymmetry of the nasal region. Three‐dimensional analysis was performed to investigate the relationship between nasal soft‐ and hard‐tissue asymmetries, as well as the changes in nasal asymmetry with age, among children with repaired UCLP (age: 6–12 years). Forty‐seven patients were included in this study. Their computed tomography records were retrieved for analysis of the 3D asymmetry of 10 landmarks of the nasal soft and hard tissues. We observed that asymmetry was more severe in nasal hard tissues than in soft tissues, particularly in the sagittal dimension. Compared with patients aged 6–9 years old, patients aged 10 to 12 years old had significantly increased vertical asymmetry at the base of the alar groove (Gbase, p = 0.027) and the lateral point of the piriform aperture (LPA), (p < 0.001). The correlation between the LPA and the alar region was weak to moderate (r = 0.290 to 0.488). In conclusion, we found no evidence of growth and development in nasal hard‐tissue asymmetry among 6‐ to 12‐year‐old children with repaired UCLP, except for the vertical dimension. Nasal soft tissue exhibited a more preferable symmetry than hard tissue, and this could be attributed to the compensatory growth of nasal soft tissue, particularly in the vertical and sagittal dimensions. The weak to moderate correlations between nasal soft‐tissue asymmetry and hard‐tissue asymmetry were observed in the three dimensions. Surgeons should consider these factors when repositioning the nasal alar and controlling the size of the nostrils.

Association of masseter muscles thickness and facial morphology with facial expressions in children

OBJECTIVE

To evaluate the potential influence of muscular capacity and facial morphology on facial expressions in children.

MATERIALS AND METHODS

A cross-sectional study was carried out on 40 healthy children (ages 9-13), without previous orthodontic treatment. Masseter muscle thickness and anthropometric facial proportions were measured using ultrasound and digital calipers respectively. A three-dimensional infrared face-tracking system was used to register facial expressions. The maximal amplitude of smile and lip pucker (representing maximal lateral and medial commissure movement) were used for analysis. Stepwise regression was used to investigate whether muscle thickness or anthropometric facial proportions were associated with the quantity of commissure movement.

RESULTS

When performing maximal smile, children with thicker masseter muscles were found to have more limited displacement of the commissures (R = 0.39; p = 0.036). When performing lip pucker, children with thicker masseter muscles were found to have greater commissure movement (R = 0.40; p = 0.030). No significant associations were found between anthropometric facial proportions and facial expressions.

CONCLUSION

Masseter muscle thickness seems to be associated with facial expressions in children. Those with thicker muscles show more limited commissure movement when smiling, but greater movement with lip pucker. This indicates that masticatory muscles may serve as a surrogate for mimic muscle activity. Facial morphology of the subjects does not seem to be associated with facial expression.