Myths
- No functional relationship of condyle and glenoid fossa – as condyle articulates with the articular eminence, and not the glenoid fossa Greene 2018
- Condyle positioning varies on the stage of mastication
- No ideal position of the condyle in the fossa, depends on fatigue of muscles, parafunction, posture, tongue pressure Rinchuse 2006
- No association between condylar position and signs of TMD Imanimoghaddam 2016
- Variation of anatomy is a predictor of TMD, 29-37%, not condyle position
- Occlusion causing TMD evidence low Turp 2012
- 30 year cohort study = no association of occlusal features with TMD. Ortho not associated with TMD. Olliver 2020
Controversy of TMD 2419 articles published – issue is the definitions of occlusion and TMD
Change occlusion terms to
- Occlusion interferences
- Occlusal sensitivity
- Occlusal Interferences
- Occlusal interferences have been suggested as the cause of bruxism – Ramfjord 1961 Both 1973
- No evidence that occlusal interference are more or less effective at TMD or bruxism List 2010, Manfidini 2018
- Usually masticatory system capable of adapting continuously to almost all types of dental interventions Greene 2015
- Artificial interference (orthodontics) in subjects with a history of TMD, caused greater TMD sensitivity Bell 2002, 2006
Investigation
- Occlusal interference bonded on healthy and pts with TMD
- Results
- Healthy subjects =reduced clenching and avoidance of occlusal disturbance
- TMD subjects = no avoidance behaviour
- Conclusion
- TMD patients have reduced occlusal adaptability
- Does daytime bruxism cause reduced occlusal adaptability?
- Results
- Healthy subjects = reduced clenching and avoidance of occlusal disturbance
- TMD subjects = reduced clenching but higher occlusal discomfort and pain
- Conclusion
- TMD patients have more pain
- What is the perception of pain in healthy and TMD patients?
- Experiment separator placed and pain recorded
- Results
- Health patients = less pain
- TMD patients = higher pain
- Conclusion
- High psychological distress and high state of anticipation and expectation = increased perceived pain
- Occlusal sensitivity Enkling 2010
- Defined – Ability to detect small changes between teeth
- Regulate jaw position, mandibular movement and occlusal force
- Range 2-27 microns
Investigation
- Periodontal pain
- TMD patients = greater occlusal sensitivity
- Muscle pain
- TMD patients = greater pain
- Caffeine
- greater occlusal sensitivity
Occlusal changes and neuroplastic change
- Modification to dental occlusion = changes neuroplastic changes to motor cortex – Avivi 2015
Conclusion
- Neuroplasticity can occur from occlusal changes (changes to motor cortex)
- Hypervigilance can cause occlusal sensitivity
- Phycological distress from maladaptation can cause TMD
