Evaluation of the Relationship between Occlusion and Temporomandibular Disorders in Six-Year-Old Preschool Children in Mashhad-Iran

The temporomandibular joint is the most complex set of joints in the human body. Therefore, its disorders need special care to be taken. In this issue, children are more at risk due to their greater susceptibility. The aim of this study was to evaluate the relationship between malocclusion and tempromandibular disorders(TMD) among the preschool children from different regions of Mashhad, Iran. For this deh1ive-observational study, 448 six-year-old children were randomly selected from pre-schools in Mashhad city. TMJ(tempromandibular joint), masticatory muscles and the occlusion status were examined and pain and tenderness of joint, masticatory muscles and tendons as well as jaw shift, clicking and crepitus during mouth opening were evaluated. Occlusion status of second primary molar or first permanent molar was also recorded. Data were analyzed using Chi-square and Mann Whitney tests. Frequency of TMD was 44.2%(14.5% with signs of clicking, crepitus, deviation, and deflection, 19.2% with muscle pain in palpation and 10.5% with a combination of muscular and joint problems). Most of the subjects had flush terminal plan in their primary molar(60.4%). Results showed a significant higher presence of TMD in subjects with reverse-overjet(P=0.007). No other significant differences were found among subjects with or without TMD in other evaluated indices. Since the frequency of TMD in children is remarkably high and children do not have the ability to express and localize their pain, dentists should look for signs of TMD on a routine schedule to minimize the long-term effects of this disorder. Further studies are needed to clarify the etiology of TMD in children.