Craniomandibular Dysfunction (CMD) after Dental Implant Restorations

Last Updated November 13, 2005

Osseonews was pleased to have the opportunity to speak with Dr. Alvaro Ordonez, a general practitioner and Director of TMJ Dental Consultants Inc, in Coral Gables, Florida. Dr. Ordonez has over a decade of experience treating patients who have developed CMD (Craniomandibular Dysfunction) after restoration with dental implants. Dr. Ordonez shares with us some of his observations and recommendations for treatment.

Osseonews: Dr. Ordonez, What is the incidence of CMD (Craniomandibular Dysfunction) in patients who have been restored using implants?

Dr. Ordonez: The true incidence is unknown. CMD is a relatively new and not well defined area of diagnosis and treatment. The biggest problem in forming an accurate estimate of the incidence of CMD would be to first implement a standardized system for evaluating these patients. This has not been accomplished yet and owing to the complexities and differences of opinion in this field, may never happen.

Our patients come to us usually because they have an existing CMD problem and we are a CMD\Facial Pain Center. We often use implants to restore the patient after we have ameliorated the CMD problems. We really are not seeing a true picture of the normal range of TMJ function for these patients simply because our patient population is very heavily weighted with patients with CMD.

If is very difficult to generate reliable data for the kinds of studies that we really need in the area of CMD. Perhaps creating as specific a questionnaire as possible to evaluate cases and enlisting multiple sites for inclusion in the collection of data would give us an idea of the actual condition of the patients before implant restoration. The same patients would need to be evaluated years after implant treatment to evaluate for potential problems. Personally, I believe that the combination of missing teeth and parafunctional habits can predispose a patient to CMD that meets an academically acceptable definition.

Osseonews: Is there a greater incidence of CMD associated with a particular kind of implant restoration?

Dr. Ordonez: That has not been my observation. In the early days of implant dentistry, not having a periodontal ligament in between the implant and the bone was considered a major problem because of the lack of proprioception. This proprioception deficit was believed by some to be a potential cause of CMD. In other words, since the implants lack proprioception, they fail to generate the kinds of nervous impulses or information that trigger self-protective reflexes. This was thought to lead to unbalanced force distribution on the implants which generates CMD. Without protective reflexes the jaws would in a sense, malfunction.

We did not observe this in our patients. We did not observe a precipitous increase in CMD cases after major implant restorations. So what happened here? And by the way, this is not just my observation but the observation of many researchers and experienced clinicians.

I believe a CMD problem in any patient could be caused by or related to so many different factors that include: the presence or absence of parafunctional habits, the type of parafunctional habit, the presence or absence of stress related factors (anxiety and or depression), mandibular position (whether deviated to the sides or anteriorly or posteriorly), macro- or micro-trauma, variable adaptation response, and so on.

Any restoration, including implant restorations could be a predisposing or precipitating factor for CMD if not done properly from the craniomandibular aspect. The advantage of implants again is that they can be use to restore missing teeth, enhancing the distribution of forces and restoring mandibular position which in turn affects neuromuscular mechanics. This is especially true for the patient with posterior bite collapse. If implant restorations are managed properly they should enhance stability and assist in the dispersion of forces.

Osseonews: How does the treatment of patients with CMD involving dental implants differ from patients who do not have dental implants?

Dr. Ordonez: There really is no difference between the ways we diagnose and treat patients with natural teeth and patients with implants. The point is that patients with CMD usually have multiple problems including: muscle disorders, joint related problems or internal TMJ derangements, Cervical Spine dysfunction, postural problems and complications from systemic medical problems. It is very rare to find a single problem; we usually find multiple problems that collectively produce the CMD.

After we arrive at a diagnosis, we often find that we have to work with other health care professionals because of the complexity of the many factors involved. All the parts of the body are linked together and often one pathosis can have repercussions on other structures and functions. Treatment may involve splints, physical therapy, spray and stretch, manipulation, electromyography, Botox, and other therapies.

Osseonews: What type of treatment would you recommend if a patient develops CMD after implant restorations? How does this differ from CMD caused by the restoration of natural teeth?

Dr. Ordonez: The first thing the dentist has to do is to assess the situation, is it primarily muscular? Is it primarily articular? Are we dealing with multiple factors? Once the dentist determines the etiology of the problem, he should inform the patient and proceed with the treatment.

Splint therapy is often used, especially for muscular problems. Being familiar with multiple designs of splints is extremely useful. Although there are many schools of thought, this would often be your initial therapy. If the primary component is muscular, use a muscle relaxant temporarily or medications like cyclobenzaprine or even diazepam at night, to relax the muscles and induce the patient into a deep phase of sleep (which will decrease the incidence of parafunctional habits). If the problem is articular, then analgesics and anti-inflammatory medications are even better. Our experience suggests that there is a higher incidence of muscular disorders as a primary causative factor than articular.

Your best friend and your best strategy will always be a good splint (a night guard) right after treatment (it is like buying insurance). It will work as a shock absorber and it will distribute the forces even better and more precisely and it will wear down rather than the restorative material, natural teeth, bone or the implant and its components.

We recently conducted a study in which we recalled our CMD patients from 1999, 2000 and 2001 that were finished with dental implants and implant restorations. The results and conclusions of our study were very interesting.

Most of the problems were related to patients that stopped wearing their splints after the fifth year of maintenance, and the most common complication was fracture of the prosthetic ceramics. Think about it, low fusing ceramics fracture very easily. In fact, I have heard Gerard Chiche mentioned that these ceramic systems are still undergoing re-invention! Well, it is an advantage in these cases since I would rather see ceramic fracturing than implants and components fracturing and bone lost. “It is easier to replace the ceramic on top rather than the titanium under the ceramic.” The actual concepts of Dr Carl Misch have been tested in our patients, and results have been extremely interesting, since our implants are abused by clenchers and grinders every day of their lives.

Progressive loading in patients that have a history of CMD is a must! When we don’t progressively load, organizing the occlusion is really hard, and becomes problematic, especially if they have dual bite. Having a progressive transition from temporary restorations to permanent restorations is the way to go, especially in the posterior segment.

Developing the implant site from the beginning with atraumatic extractions and then enhancing the site by bone grafting is a must, so you may place the widest and longest implant for that specific site. Always extend the restoration and your implants to the second molar because the second molar absorbs and protects a great deal of forces that otherwise would be transferred to the TMJ.

Reject the concept of First Molar Occlusion. First Molar Occlusion is a very sad concept in the times that we live; this might create some controversy, but think about it. Where does this concept come from? It comes from the times of lack of resources to elevate sinuses and graft bone. It used to be tough to do sinus elevations and bone grafts. We didn’t know as much then as we know today about regeneration. Today I strongly recommend that if you want to plan your case considering the TMJ and biomechanics and occlusion, do everything you can to include the second molar, and try to create occlusal tables that resemble that of the original dentition. If wide implants are not possible, then plan for a Premolar looking type of crown. I want to be sure I am understood on this critical point. If you cannot use wide implants to support a Second Molar Occlusion, switch to a Premolar design for your second molar crown. This should be your standard operating protocol.

For the patients with a history of CMD, you want to wait long enough for osseointegration before you initiate temporary or permanent restoration. We have immediately loaded a good number of them, but we have used Botox in the masticatory muscles to decrease the applied parafunctional forces and this works well. Remember Planning, planning, planning!

There is a significant advantage of using single dental implants, since the forces would not rest only on the remaining natural teeth and so the remaining teeth would not be overloaded, so distribution would be better with dispersion of forces. We could now extend the occlusal span by adding a restoration in the first and second molar areas.

Osseonews: What is the success rate in treating patients with CMD and dental implant restorations compared to patients with natural teeth?

Dr. Ordonez: That is a very complicated question to answer but we have been analyzing the data that we have been collecting in comparing the two scenarios. I can also tell you that I know of at least another group looking at that too. Success is very high, similar to normal patients; complications are more related to the implant prosthetics.

We recently recalled 50 patients in September with more than 6 years of implant placement (47 showed up) a total of 141 Wide Diameter Implants. Most of these patients had Wide Diameter Implants with an external hex. We lost 4 implants in this group, 3 in the sinus areas and I have to blame it on the technique I used since at the time we were developing a modified supracrestal technique for sinus elevation that was presented as a clinical innovation last year at the Academy of Osseointegration. The other implant was lost about six month after placement and I believe it was also my fault since it was placed in an area with a severe apical lesion that was grafted and we waited 4 month when I believe we should have waited longer. The decisions and technique played a negative role greater than the parafunctional forces.

Now, what we have seen in that group is a more extensive amount of fracture and micro-fracture of the ceramics as I mentioned before after the fifth year and it was greater in the patients that stopped wearing their splints. We recalled these patients since we were planning a lecture at the Consensus Conference in success criteria in Pisa and we wanted to give the results. We were looking for crestal bone loss that some clinicians have reported on Wide Diameter Implants. We had two implants with major crestal bone loss in the same patient (it was an early bone loss with major threads exposure), and I truly believe it was related to my management at the time of that case. I don’t think it was the implants, it was my technique. We are processing and analyzing the data now.

These patients were or are heavy clenchers and or grinders and the percentage of success was similar to the other patients who are not CMD patients. I have to admit that the percentage of porcelain breakage was tremendous, higher than non-CMD but implant success was similar (based on the new success criteria that will be published soon). So expect to have complications that are mainly prosthetic due to maldistribution of forces. My point would be that we should translate this to our regular everyday patients who are probably not from a CMD population with such elevated forces. Therefore we should calculate our biomechanic tolerance in excess to what we usually see.

The teaching, again, is planning, case selection, case management and applied biomechanics. In Contemporary Implant Dentistry by Dr Misch, you have everything you need to manage these cases (e.g., implant biomechanics). The Textbook of Occlusion by Mohl, Zarb, Carlsson and Rugh has most of what you need to know on occlusion. Clinical Management of Temporomandibular Disorders and Orofacial Pain by Pertes and Gross has up to date information on comprehensive evaluation of CMD (Facial pain patients). Myofascial Pain and Dysfunction: The Trigger Points, by Travell and Simons provides the best information on muscle mechanics and muscle physiology. I strongly encourage you to get familiar with splints. I think that the Pankey institute has the most balanced program available to dentists that practice every-day dentistry and implant dentistry.

Osseonews: What are the best strategies to prevent CMD in implant patients?

Dr. Ordonez: Identify: Find out during your initial exam if this patient has parafunctional forces or habits that are present or at some point have been present in the system. If they are present then they should be controlled and managed. If they were present at some point, then they can come back at any time so you have to prepare for it by creating mechanisms to disperse them well and to withstand them.

Differentiate: There many types of parafunctional habits and they all work differently and have different behaviors, patterns and clinical signs and symptoms. A common mistake I see in top speakers is that they relate to clenching and grinding the same way! That is a major mistake that is affecting treatment planning and case management and even the way we look at patients and conduct research! Clenching and grinding are two separate entities, that are different and they have different manifestations, and different signs and symptoms; so they also need different clinical management. We in dentistry have paid more attention to the grinder and very little attention to the clencher.

The grinder is often the easier patient to treat. Most of the dental protocols in occlusion design are created to protect the restorations from grinding. We have paid more attention to the grinder since it is very destructive dentally while the clencher is the silent enemy and it’s the habit that causes the worst problems and the symptoms that mimic medical problems. Clenching is very hard to diagnose since there is no noise, no teeth wearing. An even more serious condition is when the patient grinds and clenches.

Interestingly about long term clenchers is the fact that they very often have vertical lines of micro fractures known as craze lines. They can also have abfractions, elongation and widening of the coronoid process and muscle tenderness of the deep portions of the masseter muscle and anterior temporalis muscle. We need to use these to identify these patients as early as the first appointment so we can plan for treatment modifications that ameliorate this problem.

Another habit that is especially dangerous is known as abnormal posturing of the jaw or sometimes known as ‘crossovers’ where the patient goes out of centric into odd eccentrics that makes no sense. This habit is very difficult to diagnose and whenever using immediate loading, special care should be taken to make sure the patient doesn’t do it since they can end up banging on the recently placed and loaded implant.

Conditioning: Conditioning means creating a healthy environment in which the implant can succeed by modifying the existing abnormal occlusal set-up, eliminating the trigger points (if any) and placing the implant in accordance with the fundamentals and principles of an appropriate protective occlusal design.

Protecting: Always, after a case has been successfully loaded, the best insurance you can provide to your new implant case is the protection by the use of occlusal splints. Remember that splints can be used as preventive devices whenever you feel that occlusal forces can be a problem. Treatment guiding devices produce precise mandibular positioning which may be required in some cases to reduce symptoms. They can also help us confirm a diagnosis.

Botox is successfully being used to decrease the muscle activity of the masticatory muscles therefore eliminating applied forces to a certain degree. When used in cases of patients with parafunctional habits we decrease the applied forces and facilitate the normal process of osseointegration.

OsseoNews: Thank you Dr. Ordonez for a very enlightening discussion.
Interview conducted by:
Gary J. Kaplowitz, DDS, MA, M Ed, ABGD

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