Relationship between parafunctional habits, malocclusions and temporomandibular disorders in primary and mixed dentition[Correlazione tra parafunzioni orali, malocclusioni e disordini temporomandibolari in pazienti in dentizione primaria e mista]

Objectives: The aim of this study is to understand the relationships among oral parafunctions (such as tongue thrust and bruxism), malocclusions(monolateral posterior crossbite, deep bite, II Class) and temporomandibular disorders (TMD) and to assess whether these parafunctions may be considered a risk factor in the development of TMD. Materials and methods: Four-hundred twelve children (201 females, 211 male) were examined by the same expert orthodontist. Clinical findings were assessed by a questionnaire including parafunctional habits, malocclusions and TMD symptoms. The results were submitted to descriptive statistical analysis and Fisher's exact test. Results: The results shows that tongue thrust is positively related to TMD in boys (p = 0.023), posterior crossbite is associated with TMD both in boys and girls (p = 0.013; p = 0.05) while Class II malocclusion is linked to TMD in girls only (p = 0.036). Conclusions: The authors conclude that parafunctional habits, with the exception of tongue thrust in boys, are not statistically associated with the presence of signs and/or symptoms of TMD in the sample of children examined in this study. Class II malocclusion in girls and posterior crossbite both in girls and boys are the only malocclusions related to TMD. © 2010 Elsevier Srl. All rights reserved.