In Part two I continue the conversation about the relationship between the joint load and the occlusal contacts we create when we design an occlusion. That occlusion can be transitional on an appliance or final, created using an equilibration or restorative dentistry. Joint load is one of three considerations when designing an occlusion for a patient with a history of TMD or wear. We need to think about the relationship of the contacts to the joint load, the muscle engagement and the force across the teeth. An upcoming hands on program I will be teaching at The Pankey Institute addresses restoring the occlusally compromised patient, whether the compromise is joints, muscles or wear.
Join me at The Pankey Institute for Restoring The Occlusally Compromised Patient, no prerequisites.
Ann Marie Gorczyca says
Very interesting, Lee Ann. Very interesting comments about the anterior only appliances.
Thank you so much for posting this. I appreciate your posts very much.
Lawrence Gottesman, DDS says
Dear Lee Ann:
I think that your discussions in part one and two create intriguing and important questions related to clinical diagnosis and treatment decisions. In order to discover how the entities you discuss relate to TMD, you need to understand and answer the following questions. I would be happy to answer these questions for you should you desire. However, much of your discussion related to appliance therapy and reduction of joint loads and muscle forces is incorrect! Despite the clinical success which can be achieved through the therapy we provide the explanations for benefit will have to be answered differently.
1. What is the role of occlusion, particularly the second molar, in the articulation of the TMJ?
2. When and where is the TMJ loaded?
3. When and where is the TMJ unloaded?
4. What is the correlation between EMG, bite force, muscle force, joint loads, and joint stability?
5. What is the composition of EMG?
6. How does the composition of EMG confer the properties of joint load?
7. Is low EMG associated with reduced muscle forces and joint loads?
8. Is high EMG in the elevator muscles associated with neuromuscular incoordination?
9. What is the definition of neuromuscular incoordination?
10. How does the occlusal scheme relate to joint loads?
11. How do we explain the difference between working and non-working side EMG and joint loads?
12. How does the EMG differential correlate with TM joint disorders?
13. How do we explain degenerative joint disorders and relate them to vulnerable malocclusions based upon EMG and occlusal schemes?
14. Why can appliances create an anterior open bite?
15. What is the role of long centric in joint kinematics and joint loads?
16. What is the differential role of the condyles during jaw movement?
17. What are the posterior determinants of occlusion?
18. How can the second molar dilemma be explained in terms of these principles?
19. Why does the frequency of CR/MIP differential displacement values approach 100%?
20. Why are the condyles down and back from CR in most studies, but almost always below CR?
21. Why did nature make so many mistakes?
Lee Ann Brady says
Dr. Gottesman – thank you very much for your insight into this topic. The goal of my blog is to provide a review of my clinical experience and training and highlight the topics that top of mind for me. I certainly understand the limits of my experience and training and appreciate that your views may be unique and may even conflict with my own. Again, I appreciate your insights and thank you for the exchange of ideas/thoughts.
All the best, Lee.