Malocclusion

Malocclusion

"Malocclusion" derives from the Latin "malum," meaning "bad" or "wrong," and literally refers to an improper closure of the teeth. The notion of "closure" may seem intuitive; however, the adjective "bad" requires careful consideration, as its application in the medical context is less obvious than it may appear.

To approach an understanding of the term, this introduction poses a seemingly simple yet profoundly complex question, which in turn raises a series of related inquiries in the field of masticatory rehabilitation and, more specifically, in orthodontic disciplines: what exactly is meant by "Malocclusion"? It's interesting to note that, in 2019, a search for the term "Malocclusion" on PubMed yielded a whopping 33,309 articles, indicating a lack of uniform terminological consensus on the subject. Among these articles, some may provide conclusions of significant relevance, as strikingly demonstrated by the work of Smaglyuk and colleagues. This particularly significant study explores the interdisciplinary approach in diagnosing malocclusions:

«Diagnosis, treatment strategies, and prevention of anomalies and dento-facial deformities should be approached by considering the organism as a whole, especially in children, where the physical structure is still in the formative stage. It is essential to recognize the interconnectedness between the form and function of various organs and systems of the body, as these relationships are crucial for devising an effective treatment plan that respects and promotes the harmonious development of the patient.»

Another noteworthy piece of data emerged when, also in 2019, PubMed was specifically queried for interdisciplinary approaches in diagnosing malocclusions: the results drastically decreased to only four articles.

This observation regarding the topic of "Malocclusion" underscores two critical points: firstly, it highlights a growing awareness of anomalies that could trigger phase 4 of Kuhn's model, suggesting a potential moment of paradigmatic shift. Secondly, it signals a bifurcation in epistemic choices regarding the topic: on one hand, the tendency to generate Incremental Innovations, as evidenced by the other 33,309 articles, and on the other hand, a propensity towards a new gnoseological trajectory that favors a "Paradigmatic Innovation".

To explore the concept of "Paradigmatic Innovation", considered essential in this context, let's begin by posing a specific question:

Another noteworthy piece of data is that if in the same year, 2019, PubMed was queried about the interdisciplinarity in diagnosing malocclusions, the result dropped drastically to only four articles.

These premises regarding the question of "Malocclusion" indicate, on one hand, an alertness to anomalies that tend to trigger phase 4 of Kuhn and, on the other hand, a bifurcation in epistemic choice on the topic: one that generates Incremental Innovations (other 33,309 articles, perhaps) and another that prefers a new gnoseological path of "Paradigmatic Innovation".

Let's try to approach part of the concept that considers "Paradigmatic Innovation" essential, asking, for example:

Figure 1a:
Patient with malocclusion, open bite and right posterior crossbite who in rehabilitation terms should be treated with orthodontic therapy and/or orthognathic surgery.

What does "Malocclusion" mean?

To answer the previously posed question, let's examine a clinical case that clearly exemplifies "malocclusion".

The case involves a patient presenting a type of occlusion commonly defined by orthodontists as "malocclusion", characterized by a unilateral posterior crossbite and an anterior open bite; these conditions represent a form of malocclusion that can be effectively treated through the use of fixed orthodontic appliances, sometimes in combination with orthognathic surgery if necessary. The crossbite is identified as a significant alteration from normal occlusion, which requires concurrent treatment with the open bite due to their functional interrelationship.

It becomes clear that a deterministic approach to diagnosing such obvious occlusal incongruence might lead to considering both the crossbite and the open bite as both causes and effects of malocclusion, consequently suggesting orthodontic intervention to restore "Normocclusion". This mode of thinking would presuppose that the model (the masticatory system) should be "normalized" with respect to occlusion. Interpreted conversely, this would imply that the occlusal discrepancy is the cause of malocclusion and, by extension, pathology of the Masticatory Apparatus. (Figure 1a).

In the context of a clinical case highlighting the presence of malocclusion, with particular attention to the unilateral posterior crossbite and anterior open bite, the importance of dialogue between dentist and patient emerges. This informative conversation is crucial not only for sharing the diagnosis and treatment options but also for understanding the patient's concerns, expectations, and desires. Here's how such a dialogue might unfold:

Dentist: "Considering your malocclusion situation, which includes an open bite and unilateral posterior crossbite, treatment is recommended to improve both aesthetics and chewing functionality. Without intervention, you may experience future problems such as bruxism, swallowing difficulties, and potential postural issues."

Patient: "Absolutely not, doctor. I have no intention of undergoing any treatment. I may have an imperfect smile, but my chewing function is excellent. I eat without any issues, so I don't see why I should worry."

Dentist: "I understand that you feel comfortable with your current chewing condition. However, it's important to consider that some problems may not be immediately evident but could manifest over time, affecting not only oral health but also overall well-being."

Patient: "I appreciate your concern, doctor, but really, I have no problems chewing or swallowing. And as for bruxism or postural issues, I don't suffer from them. I'm also very physically active. For me, undergoing treatment that I don't feel is necessary would be excessive."

Dentist: "I understand your position. It's crucial that you feel comfortable with any decision made regarding your health. My role is to inform you about potential long-term implications and available treatment options. If you ever change your mind or need further information, know that I'm here to assist you."

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The situation becomes particularly critical when we consider the patient's verbal language regarding their chewing functionality. This can be misleading, as it may not reflect a detailed understanding of the pathophysiology of the occlusal state. On the contrary, it could paradoxically indicate an intact system if interpreted through a "machine language" converted into verbal terms. In this impasse, neither the patient nor the observer (dentist) can assert with certainty the presence of an actual "Malocclusion."

In this context, the reference to the American Statistical Association's critique entitled "Statistical inference in the 21st century: A World Beyond p < 0.05" becomes relevant, as it invites the researcher to navigate uncertainty with sensitivity, reflexivity, openness, and modesty in assertions. This stance paves the way for interdisciplinarity as a key to addressing such complex issues.

The interdisciplinary approach becomes crucial in interpreting the biological phenomenon of "Malocclusion" through a stochastic mindset, which will be explored in more detail later.

A stochastic observer might note that, at time $T_{n}$, there is a low probability that the patient is in a state of occlusal disease, given their expression of optimal psychophysical well-being. This leads to the conclusion that occlusal discrepancy does not necessarily entail a neuromuscular and psychophysical functional disorder. Therefore, the masticatory system should not be normalized solely to occlusion but requires a broader understanding that includes the Trigeminal Nervous System.

To assess the integrity of the patient's Trigeminal Nervous System in the presence of "malocclusion," specific electrophysiological tests were performed. The results of these tests, shown in Figures 1b, 1c, and 1d (with explanations in the captions), should be interpreted as a "Conceptual Rationale" within the context of the "Malocclusion" issue. These introductory data reveal an apparent discrepancy between the occlusal state, which traditionally might be considered pathological, and the neurophysiological data demonstrating perfect synchronization and symmetry of trigeminal reflexes.

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  Figure 1b: Figure 1b displays the results of a motor-evoked potential test obtained through transcranial electrical stimulation of the trigeminal nerve roots. The focus is on structural symmetry, which was calculated by comparing the peak-to-peak amplitude of the evoked potentials in the right masseter muscle (upper trace) and left masseter muscle (lower trace).

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  Figura 1c: This figure shows the jaw reflex evoked by percussion of the chin with a piezoelectric neurological hammer. Once again, what stands out is the observed functional symmetry, highlighted by the analysis of peak-to-peak amplitude in the right and left masseter muscles. Functional symmetry in a malocclusion condition suggests that reflexive responses of the masticatory system can remain effectively balanced despite occlusal discrepancies. This further reinforces the argument that a diagnosis of malocclusion does not necessarily translate into manifest neuromuscular dysfunctions, and that the integrity of the masticatory system can be maintained.

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  Figura 1d: Illustrates the evoked mechanical silent period elicited by percussion of the chin with a triggered neurological hammer. This type of measurement focuses on the integral area of the right and left masseter muscles, and what emerges prominently is the functional symmetry between the two sides. The presence of this symmetry underscores that, despite the malocclusion condition, neuromuscular dynamics, specifically in terms of reflex inhibition after stimulation, are maintained in a balanced equilibrium.

Through the examination of these electrophysiological data – Figures 1b, 1c, and now 1d – a picture emerges that challenges conventional interpretations of malocclusion and its clinical implications. The observed functional symmetry in these measurements indicates that the approach to diagnosing and treating malocclusions could significantly benefit from a broader evaluation, including detailed analysis of neuromuscular function. These results emphasize the importance of an interdisciplinary and integrated diagnostic and therapeutic model that goes beyond simply correcting occlusal discrepancies to include an overall assessment of the well-being of the masticatory system and, by extension, the patient.

Occlusal Dismorphisms and Not Malocclusion ......which, as we will see shortly, is an entirely different matter.

Bibliography & references