# Introduction

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We would like our reader to have an immediate perception of the topics that will be debated in Masticationpedia; we will review some of the most current issues concerning the epistemological evolution of science in general, and medical as well as dental medicine in particular...

In this phase we will consider the two fundamental aspects of Progress of Science, according to the Kuhn Paradigms, and Epistemology which questions the concepts of "Statistical Inference" and 'Interdisciplinarity'.

These two themes, which apparently seem to be in conflict with each other, as the first one needs disciplinarity to highlight the "Anomalies in the Paradigm" and the second needs "Interdisciplinarity", they will integrate through a resolving element that consists of "metacognitive scaffolds", i.e. cognitive bridges between specialist disciplines. In this context, therefore, the reader will be better able to appreciate the stochastic approach towards one of the most controversial topics in masticatory rehabilitations, such as, "Malocclusion", from which come most of the masticatory rehabilitation procedures such as orthodontics, prosthesis and orthognathic surgery.

So, in addition to anticipating the scientific and philosophical aspect of Masticationpedia, we will finally focus on topics such as "Complex Systems", the "Emergent Behaviour" of Complex Systems and "System’s Coherence": necessary steps to introduce scientific clinical topics which bring with them doubts, questions and at the same time paradigmatic innovations tending to change the status quo of the deterministic and reductionist clinical thinking routine, before a stochastic and interdisciplinary language logic.

 Article by  Gianni Frisardi

## Ab ovo[1]

Before getting to the heart of the Masticationpedia treatment, a premise is appropriate, that mainly concerns two aspects of the social, scientific and clinical reality of the current and the immediately preceding era.

In the last century, we witnessed exponential growth in technological and methodological "Innovations" specifically in dentistry[2]; these innovations have in some way influenced decision-making strategies, opinions, schools of thought and axioms in order to improve quality of life, as stated in the "Exposure Science in the 21st Century"[3]. However, this exponential growth brings with it, implicitly, conceptual gray areas (in practical terms "side effects") which are sometimes underestimated, but which may call into question some Scientific Certainties or make them less absolute and more probabilistic.[4]

The phases of paradigm change according to Thomas Kuhn

The two sensitive aspects of the current social, scientific and clinical reality (which seem to conflict with each other, but as we will see at the end of this reading will be complementary) are the "Progress of Science" according to Kuhn and the "Epistemology".

## Progress of Science according to Thomas Kuhn

Thomas Kuhn in his most famous work states that science cyclically passes through some phases indicative of its operation.[5][6] According to Kuhn, science is paradigmatic, and the demarcation between science and pseudoscience can be traced back to the existence of a paradigm. The evolution of scientific progress is assimilated to a continuous curve which undergoes discontinuity in paradigm changes. For example, in phase 2 of the Kuhn Paradigms, called Normal Science, scientists are seen as problem solvers, who work to improve the agreement between the paradigm and nature.

This phase, in fact, is based on a set of basic principles dictated by the paradigm, which are not questioned but which, indeed, are entrusted with the task of indicating the coordinates of the works to come. In this phase, the measuring instruments with which the experiments are made are developed, most of the scientific articles are produced and its results constitute significant growth in scientific knowledge. In the normal science phase both successes and failures will be achieved; the failures are called by Kuhn anomalies, or events that go against the paradigm.

As a good problem solver, the scientist tries to solve these anomalies.

### Kuhn's phases in Dentistry

Kuhn, however, divides the evolution of a paradigm into five phases; this is a fundamental process for Masticationpedia, but to keep tuned with the project, we will limit ourselves to describing the two most significant phases:

It is almost obvious that Kuhnian scientific philosophy prefers disciplinarity, as an anomaly in the genomic paradigm will be noticed better by a geneticist than by a neurophysiologist. Now this concept would seem to be in contrast with the epistemological evolution of Science, so it is better to stop a minute upon it in detail.

## Epistemology

 The black swan symbolizes one of the historical problems of epistemology: if all the swans we have seen so far are white, can we decide that all the swans are white?Really? Kuhn used optical illusion to demonstrate how a paradigm shift can cause a person to see the same information in a completely different way: which animal is the one here aside?Sure?

Epistemology (from the Greek ἐπιστήμη, epistème, "certain knowledge" or "science", and λόγος, logos, "speech") is that branch of philosophy which deals with the conditions under which scientific knowledge can be obtained and the methods for achieving such knowledge.[7] The term specifically indicates that part of gnoseology which studies the foundations, validity and limits of scientific knowledge. In English-speaking countries, the concept of epistemology is instead mainly used as a synonym for gnoseology or knowledge theory — the discipline that deals with the study of knowledge.

Incidentally, the basic problem of epistemology today, as in Hume’s time, remains that of verifiability.[8][9]

The Hempel paradox tells us that each sighted white swan confirms that crows are black[10]; that is, each example not in contrast with the theory confirms a part of it:

${\displaystyle A\Rightarrow B=\lnot A\lor B}$

According to the objection of falsifiability, instead, no theory is ever true because, while there are only a finite number of experiments in favour, there is also theoretically an infinite number that could falsify it.[11]

 But it’s not all so obvious...

...because the very concept of epistemology meets continuous implementations, like in medicine:

 ${\displaystyle P-value}$: In medicine, for example, to confirm an experiment, a series of data coming from laboratory instruments or from surveys, the "Statistical Inference" is used, and in particular a famous value called "significance test" (P-value). Well, even this concept, now part of the researcher's genesis, is wavering. In a recent study, attention was focused on a "Campaign" conducted on "Nature" against the concept of "significance tests"[12].With over 800 signatories supporting important scientists, this "campaign" can be considered an important milestone and a "Silent Revolution" in statistics on logical and epistemological aspects[13][14][15]. The campaign criticizes the too simplified statistical analyses that can still be found in many publications to date.This eventually led to a discussion, sponsored by the American Statistical Association, which spawned a special issue of "The American Statistician Association" titled "Statistical Inference in the 21st Century: A World Beyond p <0,05", containing 43 articles by forward-looking statisticians[16]. The special question proposes both new ways to signal the importance of research results beyond the arbitrary threshold of a P-value, and some guides to conduct of research: the researcher should accept uncertainty, be reflective, open and modest in his/ her statements[16]. Future will show whether or not those attempts to statistically better support science beyond the significance tests will be reflected in future publications[17]. In this field too, we are on the same wavelength as the Progress of Science according to Kuhn, in that we are talking about the re-modulation of some descriptive statistical contents within the scope of disciplinarity. Interdisciplinarity: In science policy, it is generally recognized that science-based problem solving requires interdisciplinary research (IDR), as proposed by the EU project called Horizon 2020[18]. In a recent study, the authors focus on the question why researchers have cognitive and epistemic difficulties in conducting IDR. It is believed that the loss of philosophical interest in the epistemology of interdisciplinary research is due to a philosophical paradigm of science called "Physics Paradigm of Science", which prevents recognition of important IDR changes in both the philosophy of science and research.The proposed alternative philosophical paradigm, called "Engineering Paradigm of Science", makes alternative philosophical assumptions about aspects such as the purpose of science, the character of knowledge, the epistemic and pragmatic criteria for the acceptance of knowledge and the role of technological tools. Consequently, scientific researchers need so-called metacognitive scaffolds to assist them in the analysis and reconstruction of how "knowledge" is constructed in different disciplines.In interdisciplinary research, metacognitive scaffolds help interdisciplinary communication analyse and articulate how the discipline builds knowledge[19][20]

## P-value vs. Interdisciplinarity

Given the above, on a superficial view of the epistemic evolution of the Science, the two aspects of disciplinarity ("Physics Paradigm of Science", highlighting the anomaly) and Interdisciplinary ("Engineering Paradigm of Science", metacognitive scaffold), might seem to be in conflict with each other; in reality, however, as we are just going to see right in this chapter, they are two sides of the same coin because both tend to generate "Paradigmatic Innovation" without any conflict at all.

Now we could conclude that the "Innovations" are already "Progress of Science" in themselves, as stated in the article "Scientific basis of dentistry" by Yegane Guven, in which the effect of biological and digital revolutions is considered on dental education and daily clinical practice, such as personalized regenerative dentistry, nanotechnologies, virtual reality simulations, genomic information and stem cell studies.[21] The innovations mentioned by Guven are obviously to be considered as technological and methodological in nature; however, the Progress of Science does not move forward with this kind of Innovations, which are called "Incremental Innovations" and "Radical Innovations", but it occurs substantially through "Paradigmatic Innovations".

In the strictest sense of the phrase, "Paradigmatic Innovations" are essentially a change of thought and awareness that pervades the whole of humanity, starting from different social strata, from the Copernican scientific revolution to the current trend of Stochastic approach to the biological phenomenon[22].

In this epistemological context (in addition to other initiatives such as the Research Diagnostic Criteria in the field of the Temporomandibular Disorders — RDC/TMDs), of the Evidence Based Medicine (and other), the Masticationpedia project inserts itself in order to highlight the dialectics dynamism about the progress of the masticatory rehabilitation science. Masticationpedia tends, moreover, to highlight the anomalies that inevitably stimulate a change of thought and therefore a "Paradigmatic Innovation".

Before proceeeding, it could be appropriate to observe a very concrete and significant case.

## Malocclusion

Malocclusion: it literally means a bad (malum, in Latin) closure of the dentition[23]. The closure is easy to understand, we believe, but the epithet "bad" must be understood with care as well, because it is not as simple as it seems.

To briefly grasp the concept, in this first introductory reading we will try to present a simple but highly debatable question that involves a series of other questions in the field of masticatory rehabilitation and especially in orthodontic disciplines: what is "Malocclusion"? Bear in mind that in 2019, a Pubmed query about this term returned a result of "only" 33,309 articles[24], which says it all about the hypothetical terminological agreement on the subject; and, therefore, very meaningful conclusions could be drawn every now and then from these articles, such as the ones we reproduce in full from an article by Smaglyuk and collaborators, a somewhat "sensational" article that deals with the interdisciplinary approach in the diagnosis of malocclusions[25]:

«The diagnostics, treatment tactics and prevention of dento-facial anomalies and deformations should be considered in the context of the integrity of the child's unformed organism, the interdependence of the form and functions of its organs and systems»

Another noteworthy fact is that if in the same 2019 Pubmed was questioned on interdisciplinarity in the diagnosis of malocclusions, the result dropped drastically to just four articles[26].

These premises to the "Malocclusion” question indicate, on one hand, an alert about anomalies that tend to activate Kuhn phase 4 and, on the other, a bifurcation in the epistemic choice on the subject: one that generates Incremental Innovations (others 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 the "Paradigmatic Innovation” as essential, asking ourselves 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?

We will answer this question by reporting a clinical case of evident “Malocclusion”.

Patient is with an occlusion that orthodontists call “Malocclusion” because it has a posterior unilateral crossbite and anterior openbite[27]; it is a malocclusion that can be treated with a fixed orthodontic therapy and possibly in combination with an orthognathic intervention[28]. Crossbite is another element of disturbance in normal occlusion because of which it is obligatorily treated together with the openbite[29][30][31].

It is self-evident that an observer with a deterministic mindset facing a phenomenon of such evident occlusal incongruity considers crossbite and openbite the cause of malocclusion (cause/effect) or vice versa; and it is obvious, as well, that the observer recommends an orthodontic treatment to restore a “Normocclusion”. This way of reasoning means that the model (masticatory system) is “normalized to occlusion”; and if read backwards, it means that the occlusal discrepancy is the cause of malocclusion and, therefore, of disease of the Masticatory System. (Figure 1a).

But let's hear what the two players say, the dentist and the patient, in the informative dialogue.

Figure 1b: Motor evoked potential from electrical transcranial stimulation of the trigeminal roots. Note the structural symmetry calculated by the peak-to-peak amplitude on the right and left masseters.
 The dentist tells the patient that he is suffering from severe malocclusion and that it should be treated to improve its aesthetics and chewing function. The patient, however, replies firmly: «No way, I haven't the slightest idea to do it at all, doctor, because I might even have an unrepresentative smile, but I eat very well.»The dentist’s reply is ready, so the practitioner insists by saying: «but you have a serious malocclusion with an openbite and a unilateral posterior crossbite, you should already have problems with bruxism and swallowing, as well as posture.»The patient closes the confrontation in a decisive way: «absolutely false: I chew very well, I swallow very well and at night I snore alot so I don’t grind; besides, I’m a sportsman and I don’t have any postural disturbance».

Now the conclusion remains very critical because we might be finding ourselves in front of a verbal language of the patient which is misleading because it is not specific and does not respond to a detailed physiopathogenetic knowledge of the occlusal state; or, paradoxically, we are otherwise facing a machine language converted into verbal language which guarantees the integrity of the system. At this point the situation is truly embarrassing because neither the patient nor the observer (dentist) will be able to say with certainty that the System is in a “Malocclusion” state.

Figure 1c: Mandibular reflex evoked by percussion of the chin through a triggered neurological hammer.
Note the functional symmetry calculated by the peak-to-peak amplitude on the right and left masseters.

It is precisely at this moment that one remembers the criticism of the American Statistician Association titled “Statistical inference in the 21st century: A World Beyond p <0.05”, which urges the researcher to accept uncertainty, be sensible reflective, open and modest in his statements[16]: which basically translates into a search for interdisciplinarity.

Interdisciplinarity, in fact, could answer such a complex question; but it is nonetheless necessary to interpret the biological phenomenon of "“Malocclusion”" with a stochastic forma mentis of which we will discuss in detail later.

A stochastic observer may observe that there is a low probability that the patient, at the moment ${\displaystyle T_{n}}$, is in a state of occlusal disease, as the patient's natural language indicates ideal psychophysical health; he/she then concludes that the occlusal discrepancy could not be a cause of neuromuscular and psychophysical functional disorder. In this case, therefore, the Masticatory System can not only be normalized to the occlusion only, but a more complex model is needed too, so it has to be normalized to the Trigeminal Nervous System. The patient was then served a series of trigeminal electrophysiological tests to assess the integrity of his/her Trigeminal Nervous System in these “"Malocclusion”" clinical conditions.

Figure 1d: Mechanical silent period evoked by percussion of the chin through a triggered neurological hammer. Note the functional symmetry calculated on the integral area of the right and left masseters.

We can see the following output responses, which we report directly in figures 1b, 1c and 1d (with explanation in the caption, to simplify the discussion). These tests and their description by now should only be considered as “Conceptual Rationale” for the “Malocclusion” question; later they will be widely described and their analysis detailed in the specific chapters. It can already be noted in this first descriptive approach to the masticatory phenomenon that there is an evident discrepancy between the occlusal state (which at first would support the orthodoxy of classical orthodontics in considering it as “Malocclusive State”) and the neurophysiological data indicating incredible synchronization and perfect symmetry of the trigeminal reflexes.

These results can be attributed to anything less than a "malocclusion": we are obviously in front of an error of the logic Language in medicine, in this case it is in fact more appropriate to talk about...

 Occlusal dysmorphism and not Malocclusion (which, as we shall see a little further on, is quite another thing)

## Conclusion

Even before drawing conclusions, conceptual clarity must be made on some fundamental points which of course will be treated in detail in the specific chapters of Masticationpedia.

The Masticatory System should be considered as a “Complex System[32], not as a Biomechanical System focused exclusively on dental occlusion, because in this sense the “Occlusion” is nothing more than a subset of the Complex System interacting with the other subsets, such as periodontal receptors, neuromuscular spindles, recruitment of motor units, central nervous system, temporomandibular joint, etc., to give shape to an “Emerging Behaviour”, the masticatory one.

The peculiarity of this concept is that it is not possible to interpret or predict the “Emerging Behaviour” of a System by extracting objective data from a single subset. Instead, the integrity of the System must be quantified in its entirety, and only then can a segmentation of the whole be attempted to make an analytical description of the node itself. There are very important intellectual and scientific movements that are engaging with this issue; in this regard, the extraordinary work of Prof. Kazem Sadegh-Zadeh: Handbook of Analytic Philosophy of Medicine comes to mind.[33]

In the presented case, the question is resolved in the following language logic:

The subsets of the Masticatory System (teeth, occlusion, Temporomandibular joints, muscles, etc.) are in a state of "Coherence” with the Central Trigeminal Nervous System (see figures 1b, 1c and 1d), so the term “Malocclusion” cannot be used, the phrase “Occlusal Dismorphism” should be considered instead.
«This does not mean abolishing prosthetic, orthodontic and orthognathic masticatory rehabilitation treatments: on the contrary, this forma mentis tends to restore medical knowledge to dental rehabilitation disciplines, as well as offering an alternative to the scientific reductionism that converges in a deterministic interpretation of the biological phenomenon.»

Going beyond the specialist perimeters of the disciplines, as previously reported on interdisciplinarity, helps expanding the diagnostic and therapeutic models as it can be seen in the Clinical case in which a patient was treated with the OrthoNeuroGnathodontic method is reported.

In this way, an overall view of the entire Masticatory System is presented in order to gather the aesthetic and functional-neurophysiological components together to determine “Occlusal Stability” and to avoid “Relapses”, especially in orthodontic and orthognathic treatments.[34][35]

These are just some of the topics that will be covered extensively both in this chapter and in what we call “Extraordinary Science”. Meanwhile, in a fitting diversion our colourful friend Linus Sapiens, the little yellow man on the left, asks us:

«What do we mean by “Complex Systems” when we are talking about masticatory functions?»
(Not a trivial question, let's start talking, then, about the logic of medical language)

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