On the three-dimensional physiological position of the temporomandibular joint

Despite intensive research regarding the position of the temporomandibular joint, only few evidence-based facts are known about a three-dimensional physiological condyle-fossa relationship. The aim of this systematic literature review was therefore to summarize the existing literature regarding the condyle position and to draw conclusions about a standardized three-dimensional condyle position. An extended search profile based on the search strategy of the Cochrane Oral Health Group and applied to twelve medical databases was used to identify existing studies. Articles which were not electronically accessible (mainly those published before 1960) were identified from reference lists and bibliographies. These publications were assessed independently by two clinicians with reference to points based on specified criteria. The interexaminer agreement was assessed on the basis of the kappa coefficient.1903 articles published in the period 1899-2001 and relating to condyle position were identified. These studies showed a pronounced variability in their methodological approaches, with only 49 of them meeting the inclusion criteria. The interexaminer agreement yielded a kappa-value of 0.92. Although numerous studies used three-dimensional data, no physiological three-dimensional condyle position was determined. The most frequent analytic method was two-dimensional projection of the temporomandibular joint onto a subjectively selected sagittal plane. This evaluation method revealed a noticeable shift over time in condyle position from posterior to anterior, suggesting a clear-cut publication bias. Publications with the highest evidence level favored no specific position (p > 0.05). Simplification of the three-dimensional structure of the temporomandibular joint to a two-dimensional projection is questionable for therapeutic positioning of the condyle in relation to the fossa.