Temporomandibular disorder (TMD) is a widespread and common disease and therefore also an economic problem for the health care system. The prevalence of pain associated with muscles of the temporomandibular region is about 10% and 11.4% of the population suffer from a disc displacement with reduction . Women are more likely to suffer from TMD than men .
The clinical signs and symptoms of TMD are heterogenous. Most patients report of pain in the muscles of the stomathognathic system (i.e. myalgia) or pain or dysfunction of the temporomandibular joint (i.e. arthralgia, arthritis, disc displacement with/without reduction). Additionally other factors, like trauma, psychological or orthopedic disturbances can affect TMD .
The modern aetiological concept of TMD is mainly based on research by Dworkin and LeResche in the 1990s. Their research diagnostic criteria for temporomandibular disorders (RDC/TMD) considers somatic as well as psychological and social co-factors. The first axis includes a clinical examination that focuses on the muscles of the temporomandibular region and the status of the temporo-mandibular joint (pain/dysfunction). The second axis mainly focuses on the patient’s history including a graded chronic pain status, a jaw disability checklist, tools to evaluate the patient’s depression and non-specific physical symptoms and a checklist to gain detailed demographic information .
Today the RDC/TMD are commonly used by clinicians and investigators over the world since there are many translations available such as the German version .
Although occlusion remains unconsidered in the RDC/TMD instrument, dentists traditionally focus on it as a major aetiological factor. In addition, occlusion seems to be the only component of the stomathognathic system they are able to change structurally and morphologically.
As the role of occlusion is still unclear , the clinician should be careful in changing the patient’s occlusion irreversibly from the beginning. A temporary and reversible improvement towards a well-balanced static and dynamic occlusion should be the first step, which is mostly realized by a customized acrylic splint fabricated after registration of the centric condylar position (CCP). The patient is instructed to wear the splint several hours in the daytime and the whole night. In many cases this treatment leads to a relief of pain and an improvement in joint function .
This first therapeutic step might then be followed by other, more invasive and irreversible procedures such as prothodontics or orthodontics. These therapeutic options apply especially to patients who require prosthodontic or orthodontic intervention a priori. The sticking point of these interventions following splint therapy is precisely transferring and therefore maintaining the CCP.
The following article describes the orthodontist’s approach for transferring and maintaining a therapeutic condyle position into permanent occlusion using the Incognito-System (3M Unitek, Monrovia, USA).