Traditional Beliefs of Evidence-Based Research or Meta-Analyses of Scientific and Objectively Derived Data

Article Written by Bruce Greenstein, DMD, Pinecrest (Miami), Florida

The question to ask of this doctor is “What are your “traditional beliefs”?

Part of the challenge in the TMJ arena is that it is significantly more difficult to perform “evidence-based” research or meta-analyses of “scientific” and objectively derived data. It is far easier to compare in the lab when evaluating the strengths of certain biomaterials – subjecting them to multiple tests in vitro by crushing or plying them apart and recording all the numbers and data for comparison. In those situations, very specific protocols can be followed and monitored throughout the experiment. The same holds true for comparing the seal of root canal treated teeth when you section them and use dyes to identify leaks.

Within the NM arena, we can objectively evaluate muscle EMGs and determine whether hyperactive vs “normal” (though work must be done to determine whether some muscles are relaxed versus fatigued as well as trying to compare electrode placement, interface with the skin surface and differences in muscles from one person to another affecting scan results). ESGs tell us about the location and intensity of noises and we interpret what is occurring within the joint complex based on spikes and deviations in the scans. CMS indicates the extent and quality of Md movement all of which is influenced by multiple factors – agreed.

To claim, as many doctors do, that evidence-based approaches to this science prove that occlusion plays only a minor (10-15%) role in symptoms ascribed to TMJD is disingenuous. I would ask how such articles evaluated the role played by bite adjustments – a “placebo effect”? Dentists pretending to adjust teeth, but really didn’t and the patient claimed all TMJ symptoms disappeared? What kind of evidence-based follow-up was done on these patients? How did one quantify that the patient had TMJ symptoms to begin with? Was the bite adjusted in CO or done in the old or new CR position or with use of ULF TENS unit?? So many variables to try to control, it’s no wonder things seem all over the place!

As just one example of bias, a recent author’s response under the heading “Rationalism” as erroneous support for successful splint therapy reads as follows …. “This kind of “junko logic” ignores all the possible theories on how splints might work (implying that occlusion plays limited to no role). For instance, Clark offers 5 possibilities: occlusal disengagement, restored occlusal vertical dimension, maxillomandibular realignment, TMJ repositioning, and cognitive awareness”. This comment cements my contention above about reasoning being disingenuous. One cannot claim that gnathologists and occlusal therapy (ex. removable orthotics or “splints”) plays a limited to no role in TMJ therapy, then turn around and claim “alternate possibilities” that have everything to do with occlusion!

Occlusal disengagement = eliminating interferences (isn’t that part of occlusal therapy?)
Restored Occlusal Vertical Dimension, Mx/Md realignment and TMJ repositioning all occur by virtue of using OCCLUSION-ORIENTED SPLINTS! Is that not what an orthotic does? It is exactly the intricate gearing along the biting surface of a micro-occlusally, well-adjusted orthotics that allow for the change in mandibular position and TMJ realignment. Otherwise, how did the jaw position or joint complex rearrange itself in the first place?
(I’m not about to get into a debate over cognitive awareness and behavioral issues a la Orofacial Pain theory. There’s room for many sorts of treatments and if that alone does the trick, fantastic, but when it doesn’t, where to next?)

This entire arena is based on a combination of BOTH objective data gathering and subjective data gathering from both doctor and patient. At no point have I seen anywhere how the GNM approach has discounted the role of posture, airway, soft tissue anatomy, health history or anything else that can influence outcomes in this field. The OC manuals are replete with references to these areas of influence. The pissing contest between CR, NM, PBD, BFDO, GNM, OFP (any other acronyms?) is ego-driven and fraught with political motivations that have less to do with patient and more to do with those debating.

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