Occlusal Vulnerability Hypervigilance, Neuroplasticity And Adaptation Ambra Michelotti. Episode 58. IOC 2020

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Farooq Ahmed


  1. No functional relationship of condyle and glenoid fossa – as condyle articulates with the articular eminence, and not the glenoid fossa Greene 2018
  2. Condyle positioning varies on the stage of mastication
  3. 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
  4. 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


  1. 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



  • 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


  1. Occlusal sensitivity Enkling 2010
  • Defined – Ability to detect small changes between teeth
  • Regulate jaw position, mandibular movement and occlusal force
  • Range 2-27 microns



  • 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



  • Neuroplasticity can occur from occlusal changes (changes to motor cortex)
  • Hypervigilance can cause occlusal sensitivity
  • Phycological distress from maladaptation can cause TMD
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