The gate keeper for each biological system is responsible for detecting and managing disease and parafunction. The dental profession has not succeeded in this endeavor as evidenced by the global epidemic of temporomandibular disorders (TMDs). At heart is the profession’s failure to distinguish between two distinct forms of parafunction: horizontal grinding (bruxism) and vertical clenching (dental compression syndrome or DCS), embracing one while ignoring the other more serious threat to the TMJ.

It was only natural that the profession focused on bruxism. The flattened dentitions in the old skulls were testament to its presence since the beginning of time while signs of DCS did not appear until the 19^th century. It was not apparent then that a guard would provide protection, so management took the form of equilibrating the occlusal surfaces to teeth to reduce bruxism’s forces [1]. Subsequently, a paradigm began to develop, seeking the best way that teeth should touch that would be the least susceptible to destructive lateral forces. It was termed “optimum function occlusion” [2]. Unfortunately, it was an error of judgment that would cloud our understanding of the mastication system for decades. This contradictory phrase erroneously describes dysfunction and closure as functional. It implies an occlusal destination as a goal rather than a more holistic approach to evaluating the system.

There was confusion. The American Dental Association (ADA) seeking clarity initiated three conferences to interpret the general concept of occlusion to fit comfortably into a dental school’s curriculum [3]. The first conference (1952) was chaotic with only one point of agreement: that any concept of occlusion should fit into one of two categories, “harmonious medium occlusion” (functional) and “disharmonious peripheral occlusion” (parafunctional). Unresolved, the 1975 conference again sought to define end goals without success. However, one important point of clarity did emerge from that meeting: Dr. Parker Mahan stated that a preferred goal was “to understand normal stomatognathic system function, to recognize occlusal dysfunction to determine its etiology, and how to treat it”. Dr. Mahan was spot-on. The dental community needs to recognize the limitations of the term “occlusion”, which has been overused, confused, and extended beyond its meaning; instead, it should develop a more comprehensive understanding of all the contributing factors to mastication disorders. This brings us to temporomandibular disorders.

Why are TMDs such an enigma? While developmental disorders, osteoarthritis, and trauma play a role in TMD etiology, at the heart of this misconception lies the profession’s inability to grasp the complexity of parafunction. Falling under the umbrella of bruxism, [4] clenching and grinding are two fundamentally distinct and powerful activities that differ not only in their force application to the TMJ, but in their management. Unfortunately, the dental community has completely embraced and accommodated bruxism while ignoring DCS. While horizontal parafunction results in the condyle gliding past the discs with reduced impact, vertical parafunctional forces, which are twice as powerful and lasts twice as long [4], force the condyles to target the menisci directly, leading to microtrauma, inflammation, and eventual displacement. When displacement did occur, symptom management prioritized preventive measures by replacing the damaged cartilage discs with Teflon-coated implants. This strategy exacerbated the condition, resulting in the recall of 25,000 implants with one implant working its way into the brain: the cause, clenching [5]. While clenching and grinding share certain central nervous system triggers, DCS has an extensive etiological portfolio that includes medications, exercise, sports, sleep apnea, pain, fear, and stretching [6]. Clenching doesn’t seem to bother most people as it is quiet within one’s subconscious. So, when problems occur, such as TMDs, damaged dentition, and alveolar bone loss, the focus is on the target, not the source. Unlike bruxism, where a guard will suffice during sleep, DCS requires patients to monitor themselves while awake, but it’s the practitioner’s mandate to recognize the signs to alert the patient. The application of a small question mark on a patient’s cellphone is a helpful reminder.

Conclusions

Using the term “occlusion” to refer to the mastication system has been troublesome and confusing. It is a significant oversimplification and can be considered misdirection in understanding the complexity on this biological system. A common inquiry asks the relationship of occlusion to TMDs? It would be better to question the liability of parafunction in the etiology of TMDs and then ask whether occlusion initiates the parafunction.

References

1. McCoy G (2024) The Story of Occlusion. J Oral Implantrol 50: 561- 562. [Ref.]
2. McCoy G (2024) A suitable Occlusion. British Journal of Healthcare and Medical Research 11: 79-80.
3. McCoy G (2021) The Most Controversial Subject in Dentistry. Int J Dent Oral Health 7: 1-4. [Ref.]
4. Paesani DA (2010) Bruxism: Theory and Practice, Quintessence Publishing Co. Ltd, United Kingdom
5. Wall Street Journal (1996).
6. McCoy G (1996) Dental Compression Syndrome, A New Look at an Old Disease. J Oral Implantrol 5: 35-49. [Ref.]

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Article Information

Article Type: OPINION ARTICLE

Citation: McCoy G (2025) Occlusion Confusion and Temporomandibular Disasters: How the Dental Profession Lost its Way. Int J Dent Oral Health 11(2): dx.doi.org/10.16966/2378-7090.433

Copyright: © 2025 McCoy G. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Publication history: 

Received date: 19 Mar, 2025

Accepted date: 12 May, 2025

Published date: 16 May, 2025