Epidemiological Evaluation of the Multifactorial Aetiology of Wedge-shaped Defects

Objectives: The purpose of this study was to determine risk factors for the aetiology of wedge-shaped defects using dental and medical variables obtained in a population-based sample of the cross-sectional epidemiological ”Study of Health in Pomerania” (SHIP). Materials and Methods: Medical history, dental, and sociodemographic parameters of 2707 subjects aged 20 to 59 years with more than 4 natural teeth selected representatively and according to age distribution (age range: 20-59 years) were checked for correlations with the occurrence of wedge-shaped defects using a multilevel logistic regression model on a tooth and subject level. Results: The risk of developing wedge-shaped defects generally increased with age (except among 45- to 49-yr-olds). Following independent variables were found to be correlated with the occurrence of wedge-shaped defects: buccal recession of the gingiva odds ratio (OR)= 6.7; occlusal wear facets of scores 1, 2 and 3 OR= 1.5, 1.9, 1.9; tilted teeth OR= 1.4; inlays OR= 1.6 and tooth brushing behaviour OR= 1.9 to 2.0 (two times and tree times daily vs. ones a day). Maxillary and mandibular teeth behaved similarly in terms of wedge-shaped defects, with the exception of mandibular canines, which had a much lower risk of incurring wedge-shaped defects than do maxillary canines. First premolars had the highest risk for developing wedge shaped defects, followed by the second premolars. Conclusion: The results of this risk analysis indicated that the aetiology of wedge-shaped defects is multifactorial. The development of wedge-shaped defects probably results from the interaction of occlusal forces, which may produce a flexural load on the teeth and the abrasion of hard tooth substance caused by the toothbrush. Factors influencing occlusion comprised inlays and altered tooth positions.