A clinical study of oral tori in southern Thailand: prevalence and the relation to parafunctional activity.

The objective of the present study was to investigate the relationship of oral tori and occlusal stress as indicated by parafunctional activity (clenching and grinding) and to report the prevalence of torus palatinus (TP) and torus mandibularis (TM) among patients attending a dental school hospital in southern Thailand. Six-hundred-nine individuals, 183 males and 426 females, were interviewed and examined for the presence of clenching and grinding habit. The presence of TP and TM was also examined in each individual and in the case of TM size was recorded. Tabulated analysis was carried out to find the crude relationships of the parafunction, age and sex to the presence of TP or TM. The relationships were then analyzed by logistic regression. Of these individuals, 376 (61.7%) had TP, whereas 182 (29.9%) had TM. The male:female prevalence ratios of TP and TM were 1:1.4 and 1:0.94, respectively. TP was, thus, more frequent in females. A strong association between clenching and grinding and the presence of TM was found. The presence of TM might be useful as a cue to look for signs of parafunction.