Evaluation of oro-facial function in young subjects with temporomandibular disorders.

The aim of this study was to evaluate bite force (BF) and oro-facial functions at different dentition phases (initial-mixed, intermediate-mixed, final-mixed and permanent dentition) in children and adolescents diagnosed with temporomandibular disorders (TMDs). The sample was selected from four public schools in Piracicaba, São Paulo, Brazil. Of the 289 participants recruited, aged 8-14 years old, 46 were placed into the TMD group. TMD was diagnosed using Axis I of the Research Diagnostic Criteria for Temporomandibular Disorders (2011). Oro-facial functions were evaluated using the Nordic Orofacial Test-Screening (NOT-S), which involves both an interview and a clinical examination. BF was measured using a digital gnathodynamometer. Age and body mass index (BMI) were also considered. The data were analysed by the following tests: Kolmogorov-Smirnov test, Student's t-test, Spearman and Pearson coefficients, Qui-square test, Fisher's exact or binomial test, as indicated. Moreover, univariate and multivariable logistic regression were applied. For the TMD group, scores associated with NOT-S interview and NOT-S total were higher than for the control group (P = 0.033 and P = 0.0062, respectively). No differences in BF between genders or groups (P > 0.05) were detected. Variables included in the multivariate logistic regression were BMI and NOT-S total. Based on this analysis, NOT-S total was associated with TMDs. Reported sensory function was the specific domain within NOT-S interview that established the significant difference between the groups (P = 0.021). The TMD group also had a greater number of alterations in the face-at-rest domain of the NOT-S exam (P = 0.007). Concluding, it did not detect an association between TMDs and either dentition phase or BF. Instead, BF correlated with age and BMI. Oro-facial dysfunction was associated with TMD in the studied sample, but this association may be bidirectional, requiring further researches.

Relationship between orofacial function, dentofacial morphology, and bite force in young subjects.

OBJECTIVE: The aim was to evaluate the relationship between orofacial function, dentofacial morphology, and bite force in young subjects. SUBJECTS AND METHODS: Three hundred and sixteen subjects were divided according to dentition stage (early, intermediate, and late mixed and permanent dentition). Orofacial function was screened using the Nordic Orofacial Test-Screening (NOT-S). Orthodontic treatment need, bite force, lateral and frontal craniofacial dimensions and presence of sleep bruxism were also assessed. The results were submitted to descriptive statistics, normality and correlation tests, analysis of variance, and multiple linear regression to test the relationship between NOT-S scores and the studied independent variables. RESULTS: The variance of NOT-S scores between groups was not significant. The evaluation of the variables that significantly contributed to NOT-S scores variation showed that age and presence of bruxism related to higher NOT-S total scores, while the increase in overbite measurement and presence of closed lip posture related to lower scores. Bite force did not show a significant relationship with scores of orofacial dysfunction. No significant correlations between craniofacial dimensions and NOT-S scores were observed. CONCLUSION: Age and sleep bruxism were related to higher NOT-S scores, while the increase in overbite measurement and closed lip posture contributed to lower scores of orofacial dysfunction.

Evaluation of facial asymmetry and masticatory muscle thickness in children with normal occlusion and functional posterior crossbite.

AIM: The aim of this study was to evaluate facial asymmetry and the thickness of the masticatory muscles in young children with normal occlusion and functional posterior crossbite. METHODS: The sample comprised 72 children of both genders (64.71±7.04 months) in the primary and early mixed stage of dentition, divided into four groups: primary-normal occlusion (PriN; N=19), primary-crossbite (PriC; N=19), mixed-normal occlusion (MixN; N=27), and mixed-crossbite (MixC; N=16). The thickness of the masseter and anterior portion of the temporalis muscle at rest and during maximal clenching were assessed by ultrasonography. Facial morphology and asymmetry were evaluated by standardized front-view photographs, in which the following measurements were recorded: anterior face height (AFH), bizygomatic facial width (BFW), angle of the eye (AE) and angle of the mouth (AM) (interpupillary and commissure planes in relation to mid-sagittal plane, respectively). RESULTS: The results showed that muscle thickness did not differ significantly between the sides of the dental arches in all groups (paired t-test). Only the groups with normal occlusion presented significant positive correlation between AE and AM (Pearson's correlation test). In PriN, only body weight was significantly related to masseter thickness; in MixN, facial morphology contributed significantly to masseter thickness at rest and maximal clenching, while the covariates weight, height and age did not relate to muscle thickness (stepwise backward multiple regression). CONCLUSION: In the studied sample, children with crossbite presented greater facial asymmetry than those with normal occlusion, and a greater masseter thickness was related to larger faces in the mixed dentition.