Mandible meets maxilla - practice-oriented viewpoints and schools of thought on the topic of jaw relation

The maxillomandibular jaw relationship is of key importance in the context of prosthetic/reconstructive dentistry and dental functional therapy. Unfortunately, alterations of the definition for the location of the centric condylar position (CCP) in the past - from posterior to cranial and then to ventrocranial - have led to uncertainties. The accurate determination of the maxillomandibular jaw relationship and the transfer of this to a prosthetic restoration or an occlusal splint are subject to procedural limitations. Under good clinical conditions, the reproducibility of occlusal records and the spatial discrepancies between the recorded position and the jaw position after seating the restoration lie within a range of approximately 0.2 to 0.3 mm. Taking into consideration the guidance mechanisms of natural jaw movements, the intercuspation position (ICP) - taken up without occlusal interferences - is the target (or dependent) variable that is subordinate to the control (or independent) variables of the muscular activity and the joint positions. During manual guidance techniques for determining the jaw relationship, however, the natural guidance mechanisms of the craniomandibular system (CMS) are completely suppressed. If the standards of the dental profession are adhered to, functionally healthy patients are generally able to adapt without symptoms to alterations of the jaw position resulting from and dictated by the procedural requirements of dental treatment. This results in a new, age-appropriate, and functionally healthy state of physiological balance within the CMS. However, older patients, as well as patients with craniomandibular dysfunction (CMD) or a corresponding dental medical history, are characterized by a decreased ability to adapt. Modern rehabilitative dentistry must therefore ensure that extensive neuromuscular adaptation processes are kept to a minimum. Keywords: jaw relationship, control of jaw movements, retruded contact position (RCP), centric condylar position (CCP), craniomandibular system (CMS), craniomandibular dysfunction (CMD)