Factors affecting the mandibular range of motion in children

Purpose: identify factors that may influence the mandibular movement range (MMR).Methods: 181 schoolchildren participated, both gender, 8 to 12 years old, asymptomatic for temporomandibular disorders, according to RDC/TMD. Was performed the measurement of the maximum mouth opening (MMO) range, excursive movements of right and left laterality (RL and LL, respectively), and protrusion (PROT), being measured with the digital caliper Starret Série 799 millimeter measurements. Nutritionists registered anthropometric evaluations of height and weight.Results: average data of height and weight was: 32,23 ± 8,74 kg and 137,42 ± 9,52 cm, respectively. To the male gender we found: 49,59 ± 5,03 mm, on the MMO; 8,40 ± 1,74 mm, on the RL; 8,45 ± 1,41 mm, on the LL; 7,60 ± 1,40 mm, on the PROT; and to the female gender: 49,06 ± 4,43 mm, on the MMO; 7,77 ± 1,87 mm, on the RL; 8,02 ± 1,91 mm, on the LL; 6,89 ± 1,74 mm, on the PROT. The correlation between MMO and weight wasn´t significant (P>0,05). The variables frequently to the MMO were gender, age and height. However the gender wasn´t correlated with the MMO and LL, and without interference, after applied the regression, to the MMO, except to the PROT (P=0,001).Conclusion: the interfering factors on the movement range of MMO, RL, LL and PROT was: age, gender and height to the study sample, being the gender the less expressive variable. It´s suggested that to register the MMO, must be consider the age, height and gender, in children in between 8 to 12 years old.