The sample consisted of 316 subjects of both genders, with an age range 6-16 years divided into 4 groups: early mixed, intermediate mixed, late mixed and permanent dentition. MP was evaluated by the individual's ability to comminute a chewable test material in order to determine median particle size (X50) and distribution of particles in different sieves (¡°b¡±). BF was determined using a digital gnatodynamometer with fork strength of 10 mm. Orofacial function and orthodontic treatment need were screened using the Nordic Orofacial Test-Screening (NOT-S) protocol and Index of Orthodontic Treatment Need (IOTN), respectively. The results were submitted to descriptive statistics, normality test, analysis of variance and stepwise multiple linear regression to test relationship between MP and studied independent variables.
Variance of X50 and b between groups was statistically significant. But evaluation of variables that significantly contributed to MP variation showed that age, body mass index (BMI), BF and the presence of sleep bruxism were negatively related to X50 and the NOT-S clinical exam scores showed a positive relationship with X50.
In the studied sample, age, BMI, BF and the presence of sleep bruxism were related to better MP; but the increase in NOT-S scores was significantly related to poorer MP.