title: Odds ratio in the estimation of the significance of occlusal factors in craniomandibular disorders.
abstract: The usage of odds ratios for estimating the significance of occlusion is based on the assumption that the aetiological factors are additive and interchangeable in several different composite causes. If the factor studied is a necessary causal factor, odds ratios cannot be used in risk estimation. The present study analysed odds ratios in a sample of children half of whom had undergone an annual prophylactic elimination of occlusal interferences. The sample consisted of 178 children followed up for 5 years from the baseline age of 5 or 10. The distribution of interferences was computed for children with tenderness of the masticatory muscles ('cases'), and for children without ('controls'). Although the increase in the number of children free from interferences was not remarkable, the overall result was statistically significant (P < 0.01). None of the children free from interferences showed muscular tenderness at any of the annual examinations. Therefore, odds ratios could not be calculated in our study sample. It is concluded that estimation by means of odds ratios of the significance of occlusal factors in CMD may be misleading.
mesh_terms: D016022:Case-Control Studies; D016302:Centric Relation; D002648:Child; D002675:Child, Preschool; D003767:Dental Occlusion, Balanced; D003769:Dental Occlusion, Traumatic / Q000150:complications* / Q000628:therapy; D006801:Humans; D016017:Odds Ratio; D015203:Reproducibility of Results; D013706:Temporomandibular Joint Dysfunction Syndrome / Q000209:etiology*