An evidence-based evaluation of the concept of centric relation in the 21st century

The concept and application of a temporomandibular joint (TMJ) relationship identified as centric relation (CR) has changed significantly over the past century. Originally proposed as a biologically reasonable position where maxillary and mandibular dentures should occlude, it later was applied to the dentate population as well. The term "ideal" was used by the gnathologic dental community as they sought to define the exact details of CR in terms of condyle-fossa relationships. Assessments of patients' occlusion were then made in relation to CR, and discrepancies between the two positions were described as being problematic. Since not all dentists have accepted this concept, the clinical application of CR has become a topic of major dental confusion and controversy. To further complicate things, the formal definitions of CR have continuously changed over the past 40 years. In this paper, the biologic development of occlusal and TMJ relationships is reviewed, followed by a discussion about the validity of applying CR concepts and procedures in contemporary clinical and research settings. Special attention is devoted to the alleged relationships between occlusion, jaw positions, and temporomandibular disorders (TMDs). Current evidence suggests that it is time to stop applying CR concepts to the evaluation and dental treatment of healthy dentate individuals. For patients with TMDs, it is time to apply current concepts of biopsychosocial assessment and management rather than following the 20th century mechanistic models of fixing dental and skeletal malalignments. Keywords: occlusion, orthodontics, prosthodontics, restorative dentistry, temporomandibular joint