As part of a complete joint & muscle exam joint auscultation is necessary. We need to be able to answer the question “Where is the disc relative to the head of the condyle in rotation and translation?”. The answer to this question identifies disc position on both the medial pole and the lateral pole and helps us begin to assess the risks. Ultimately the definitive answer to this question requires an MRI, but auscultation is one early way to get an idea. The following video discusses doppler auscultation as well as demonstrating the technique and creating an opportunity to listen to an observe the sounds.
Any of you who regularly read my blog know I regularly treat TMD in my practice, both occluso-muscle disorders and joint issues. The first line of defense for many of these patients is an occlusal appliance or orthotic and the design of that device is dependent on the results of a joint, muscle and occlusal exam. Appliances fall into one of six categories based on design, regardless of the name that may be attached to it.
I’ve spent a good deal of time this summer preparing for a hands on occlusion workshop I will be teaching with Mary Osborne and Dr. Mark Kleive in January of next year. The course includes access to a protected webpage that will host hours of video content available 3 months before we meet in Glendale at my office. A key diagnostic record for analyzing a patient’s occlusion is a set of mounted models in centric relation. There are multiple ways to help a patient find centric relation, one of which is bimanual guidance (bilateral manipulation). There are also a number of materials that we can use to capture a centric relation bite record. The wax record demonstrated can be more challenging to acquire, but is more accurate and easier when mounting the models. The following is a short excerpt from a video on wax platform centric relation records.
In January of next year the Seattle Study Club Symposium will be in Phoenix. I am excited to be presenting at the meeting for the first time, and my topic is “Implant Reconstruction for the Challenging Occlusion”. One of the challenges we will be discussing are patients with deep bites. Our goal is to place the teeth esthetically in the face, create adequate inter-occlusal space while minimizing the forces and optimizing the occlusion. This short video discusses opening vertical dimension as an option for gaining inter-occlusal space and what the consequences are as we design the occlusion.
As a follow up to last week’s video on diagnosing wear, this video looks specifically at the signs of attrition. Attrition is the loss of tooth structure from rubbing the teeth together. Understanding that a patient’s wear is due to attrition is critical in assessing the ongoing risk to their tooth structure and restorations.
In this video I discuss the common causes of tooth wear. Although attrition, or grinding, is prevalent, it is not the only cause of tooth wear. In order to understand the risks the patient presents with for further destruction of their teeth or restorations, we need to understand the cause of what we are seeing.
It is routine to see patients with lower incisal edges that are worn into the dentin. The wear can be from attrition or from erosion, and is often a combination of the two. When dentin is exposed and the wear is progressing at a rate that is not age appropriate I want to do something to protect these teeth and slow the progression of the damage. When I think about possible restorative options I want to do what is appropriate, stay conservative if possible and manage the restorative challenges that are present with lower incisors due to their size and shape. These factors combined with the fabulous properties of our new composites have me using direct composite more and more in these situations.
Last week teaching a hands on equilibration course one of the participants told a story about a new patient to his office who was in active appliance therapy and frustrated because the former dentist wouldn’t move to the next step of the treatment plan and the patient felt “stuck” in the appliance. His question to me was whether it was wise to move ahead with definitive restorative therapy. So when is appliance therapy complete? The answer to that question hinges on your reasons for placing a patient in an appliance.
I know even the mention of the words centric relation probably has some readers bristling, as this is a much argued over topic. With that said the research by Lundeen and Gibbs at the University of Florida shows that we do seat our condyles into the fossa during the chewing stroke. This seated condylar position is often used as a reference position to treat patients whether as part of reorganizing their occlusion to alleviate TMD symptoms or for restorative or orthodontic treatments. The next question is do people seat their condyles other than during normal function as part of the chewing stroke. I believe the answer is yes. One of the pieces of evidence is the number of patients that I have with wear facets that correspond exactly to their first point of contact with their condyles seated. These same patients do not mark this area with articulating paper in intercuspal position or when following their excursives.
Blunting or shortening of the roots of teeth that have been moved orthodontically is commonly seen. In reviewing the orthodontic literature I learned that there is a distinction between mild root resorption and significant. If we look at any loss of root length using radiographs the number of cases where it presents is very high, estimated in some studies to be upwards of 70%. However this loss of a fraction of a millimeter of root length is not clinically impactful and often not noted on radiographs unless measurements are taken. Significant root resorption, which has clinical implications of mobility and potential premature loss of the tooth, is much less common. Studies show varying frequencies from 4-18%, depending on factors like pre-op root shape, the orthodontic mechanics used, presence of congenitally missing teeth, extraction etc.
Over the years, I have treated numerous patients with “significant” root resorption and have always found managing the occlusal forces to be a critical factor. Mobility is one of the classic findings on incisors with significant resorption, and can be very concerning to the patient as well as the dental team. One of the first things I want to do when this situation presents is an occlusal analysis. The existing functional occlusion needs to be understood in intercuspal position, end to end and excursive movements to assess the force on the mobile teeth. The next question is how you might alter the functional occlusion to reduce the forces. If I believe I can improve the mobility through altering the patients occlusion I will test this with an appliance. Based on positive results we can then make those same occlusal changes to the teeth.
One of the ways I work together with the orthodontist is to diagnose root resorption and the need to manage the occlusion prior to the removal of the brackets. I have been truly amazed with the resolution of mobility and the longevity of incisors with very severe root resorption once the forces are exquisitely controlled.