Treating TMD not so simple

In the “Ask Dr. Christensen” section of the February issue of Dental Economics® (page 65), there was a question posed concerning the differentiating and treating of “TMD.

In the “Ask Dr. Christensen” section of the February issue of Dental Economics® there was a question posed concerning the differentiating and treating of “TMD.” Dr. Christensen’s response deserves comment.

The condition known as TMD is skeletal in origin. Twenty years ago, Isberg et al (AJO 1985; (6):453-60) showed that internal derangements caused Temporalis hyperactivity (with eventual spasm, if untreated). They also pointed out that prematurities occurred every time on the ipsilateral side of the internal derangement and disappeared when the I/D was reduced - rightly concluding that equilibration should not be done until the I/D was treated. Internal derangement has been shown to be the result of retrusion of the condyle, either by bodily retrusion of the mandible or overclosure (which rotates the condyle posteriorly), or more often, a combination of both. Additionally, skeletal overclosure has been shown to cause hyperactivity in the muscles of closure (bruxism). A good article on this point, though not the only one, is by Graber (JADA 1969; 79:113545). Equilibration has never been shown to increase the vertical in correcting overclosure.

Many of the symptoms attributed to TMD have been brought about by mandibular retrusion (back, not short), which is highly associated with forward head posture, or FHP, and its many referral symptoms - otalgia, tinnitus, vertigo, headache, facial pain, and vagal-related symptoms. Examination of the cephalometric radiograph should show FHP, both by the position of the mandible and the straight cervical vertebrae shown in FHP. (Do not let a Class I ANGLE (tooth) classification fool you. If the maxilla is retruded, so is the mandible; and if the maxilla is significantly retruded, treatment is almost sure to be a failure with a very unhappy patient and doctor.)

Once the proper diagnosis has been determined, it is relatively simple to formulate a successful treatment plan; however, it is very rarely so simple as grinding away a little tooth structure.

Philip H. Witherspoon Jr, DDS
Bridgeton, Mo.

Rebuttal by Dr. Christensen

Thank you for the oppportunity to respond to Dr. Witherspoon’s comments on my answer to a question on TMD. I appreciate seeing his thoughts on the condition. Of course, there are many factors related to the cause of TMD.

After treating TMD relatively successfully for several decades, I must conclude that there are as many “theories” on TMD treatment as there are religions listed in the phone book. Clinical success is the final goal, and it can be achieved by many methods.

Gordon J. Christensen, DDS, MSD, PhD
Provo, Utah

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