The Roth Williams TMJ Research Centre

Establishing clear treatment goals in Orthodontics increases diagnostic ability thus reducing the risk of treatment failure. Treatment failures are often thought to be due to poor cooperation or incorrect wire /brace selection. Misdiagnosis is the usual culprit.

A failed orthodontic result can take the form of TMJ symptoms, instability, worn teeth, periodontal decline, or facilal balance decline. We regarded condylar displacement as a major factor in contributing to unstable results. Condylar displacement means that when a patient bites their teeth together the condyle comes out of the fossa . The result is that problems will arise. The timeline of when these problems occur will vary… but they will occur. Dr Roth used to say that you find out the "fruits of your orthodontic labor 10 years after the treatment is complete." Any change in the temporomandibular joints has a direct effect on the occlusal relationship between the upper and lower teeth. Thus correct mandibular position / condyle -fossa relationship is one of the five treatment goals.

Dr Roth said we must have goals for all areas influenced by orthodontic treatment. Roughly these can be divided into Five Areas:

  • Facial Esthetics
  • Dental Esthetics
  • Functional Occlusion
  • Periodontal Health
  • Healthy Tmj (Correct Condylar -Fossa Relationship).

We have touched upon the importance of the condylar position as a goal. To reiterate: The goal is to have the teeth hit simultaneously when the condyle is seated in an anterior superior position on the disc centered transversely. The condyles and the discs move together down the eminentia from their uppermost position in the fossae as the jaw opens. If disc displacement is complete or even partial the disc, condyle, and fossa undergo degenerative changes. This results in a change of how the condyle moves which, together with changes in jaw position result in adverse changes to the profile (ie the mandible appears to drop backwards and an open bite.)

Facial Esthetics?

When we have clear-cut goals for facial esthetics we can choose tooth movements, wires and the extraction decision to move in that direction. Talking with the family or the patient about facial harmony (as well as the other goals) allow the topic of Jaw surgery to be freely discussed.

One of the most common things seen is a facial asymmetry as viewed when looking at the patient from the front. These asymmetries are closely related to TMJ status, occlusal function tooth alignment and esthetics.

Dental Esthetics?

Dental esthetics and facial esthetics are mutually complementary. If we are to achieve proper esthetics AND proper functional occlusion we may need you, the restorative dentist to recreate the anatomical crown length that was present before the patient parafunctioned 20% to 30% away!

Functional Occlusion

It seems that the profession has forgotten that most patients need 3-4 mm of vertical overlap (overbite) of the anterior teeth to provide adequate disclusion of the posterior teeth in functional movements. Additionally the Canines need a mesial inclination to allow proper mandibular movement laterally.

Periodontal Tissues

The periodontium that supports the teeth needs an adequate thickness. If teeth are excessively flared buccally or labially the risk for recession increases. Currently there is a trend that implies that fitting all of the teeth in the arches (non extraction therapy) results in reaching ideal all of the goals listed above. This is not true. Dr Roth proposed his philosophy was based on specific goals in each of the areas discussed above. Non extraction is a treatment modality…. It should NOT be a philosophy of care!

The Roth Williams TMJ Research Centre leads University research effort on temporomandibular joint and muscle disorders. In a landmark study, the centre is tracking healthy people over time to identify risk factors that contribute to the development of these conditions. Preliminary results from this study have identified a series of clinical, psychological, sensory, genetic and nervous system factors that may increase the risk of having chronic TMJ disorders. These new findings expand our scientific understanding of the onset and natural course of TMJ disorders and may lead to new diagnostic and treatment approaches.

Additionally, researchers are using data from a TMJ implant registry and repository that collected health information from patients who received implants and from those who had implants removed. Recent studies using the data have helped researchers plan for new pain medication trials and other research projects.

Pain Studies

Because pain is the major symptom of these conditions, Our scientists are conducting a wide range of studies to better understand the pain process, including:

  • Understanding the nature of facial pain in TMJ disorders and what it may hold in common with other pain conditions, such as headache and widespread muscle pain,
  • Exploring differences between men and women in how they respond to pain and to pain medications,
  • Pinpointing factors that lead to chronic or persistent jaw joint and muscle pain,
  • Examining the effects of stressors, such as noise, cold and physical stress, on pain symptoms in patients with TMJ disorders to learn how lifestyle adjustments can decrease pain,
  • Identifying medications, or combinations of medications and conservative treatments, that will provide effective chronic pain relief,
  • Investigating possible links between osteoarthritis and a history of orofacial pain.

Replacement Parts

Research is also under way to grow human tissue in the laboratory to replace damaged cartilage in the jaw joint. Other studies are aimed at developing safer, more life-like materials to be used for repairing or replacing diseased temporomandibular joints, discs, and chewing muscles.