Normative Assessment of Maximum Mouth Opening and Neck Circumference as an Implications for Mandibular Function Evaluation

Background: Assessing mandibular function encompasses diagnostic procedures such as palpation of masticatory muscles and the temporomandibular joint (TMJ), occlusal assessment, and radiographic examinations. Measuring maximum mouth opening (MMO) is essential in evaluating conditions affecting the TMJ and surrounding structures. Previous studies have noted significant variability in MMO influenced by factors like age, sex, race, and body dimensions, highlighting the need for further demographic-specific research. Methods: This study aimed to establish normative MMO ranges in young Iraqi adults and investigate correlations between MMO and neck circumference. A multistage, stratified, and modest accidental sampling method was employed, recruiting 150 participants (75 males and 75 females) aged 18-40 from Ba'quba city. Data collection included demographic characteristics, medical history, physical examinations, and standardized measurements of neck circumference and MMO. Statistical analyses utilized Pearson correlation coefficients and t-tests to evaluate relationships between variables. Results: The mean MMO for all participants was 50.02 ± 4.09 mm, with males exhibiting significantly greater MMO (52.18 ± 4.21 mm) compared to females (47.63 ± 4.41 mm). The average neck circumference was 42.0 ± 4.8 cm for males and 36.1 ± 2.9 cm for females. Moderate positive correlations were observed between MMO and both height and weight. Additionally, partial correlations indicated relationships between neck circumference and factors such as physical activity, BMI, and blood pressure. Conclusion: The findings demonstrate significant correlations between neck circumference and MMO, suggesting neck circumference as a practical screening tool in clinical settings. The study emphasizes the variability in MMO across genders and its association with physical parameters, advocating for the integration of neck circumference in mandibular function assessments. Future research should explore additional anatomical factors influencing MMO to enhance diagnostic accuracy and patient care.