Difference between revisions of "4° Clinical case: Temporomandibular disorders"

The chapter delves into the complexities of diagnosing and treating temporomandibular disorders (TMD), challenging traditional perceptions of malocclusion by emphasizing the need to relate occlusal morphology to trigeminal neuromotor responses. A case is presented where a subject, despite clear occlusal abnormalities, shows perfect symmetry in latency, amplitude, and integral areas of the trigeminal Central Nervous System (tCNS), leading to the conclusion that not all occlusal irregularities result in masticatory disorders.

This narrative underscores a critical shift from traditional dental diagnostics towards a more integrated approach termed 'Functional Neuro Gnathology' (NGF method). This approach prioritizes the functionality of the masticatory system rather than its structural aspects alone, represented by a new diagnostic model named 'Index D is the datum of'. This model seeks to align clinical dental practice with the latest neurological insights, offering a comprehensive method for evaluating and addressing TMD.

The chapter cites a study by Ahmad and Schiffman, which reveals that 4.6% of the US population is affected by TMD, with an annual management cost excluding imaging, approximated at $4 billion. This statistic frames the discussion on the economic and healthcare significance of accurate TMD diagnosis and treatment.

Discussion transitions into an exploration of the overlapping symptoms between TMD and other craniofacial conditions, which complicates the diagnostic process. Conventional diagnostics may not adequately distinguish between different underlying causes of similar symptoms due to their overlapping nature. This overlap is often seen in patients who present with both TMD and symptoms of other craniofacial disorders, suggesting a need for a more nuanced approach to diagnosis that considers a broader range of possibilities rather than a single cause.

The text criticizes the deterministic mindset in medical diagnostics, which often fails to account for the complexity and variability of human pathology. Instead, it advocates for an indeterministic and probabilistic view of medicine, which is better suited to address the multifaceted nature of conditions like TMD.

 

 

 

 

 

The narrative concludes with a call for a broader integration of neurophysiological assessments in dental practice, particularly for complex cases like TMD. The NGF method represents a paradigm shift in TMD management, advocating for a holistic approach that considers both the dental and neurological aspects of the disorder. This approach not only improves diagnostic accuracy but also enhances treatment outcomes by addressing the root causes of symptoms rather than just managing them superficially.

 

This detailed examination and discussion aim to promote a deeper understanding of the interconnected nature of craniofacial disorders and the potential benefits of integrating neurognathological insights into dental practice. By doing so, it hopes to pave the way for more effective and comprehensive treatments that can significantly improve patient outcomes in TMD and related conditions.<blockquote>

 

 

 

 

 

 

 

 

 

'''Economic Impact of TMD''' - Discusses the significant healthcare costs associated with managing TMD, highlighting the financial importance of effective diagnosis and treatment.</blockquote>

An article by Ahmad and Schiffman<ref name=":0">Mansur Ahmad, Eric L Schiffman. Temporomandibular Joint Disorders and Orofacial Pain. Dent Clin North Am. 2016 Jan;60(1):105-24. doi: 10.1016/j.cden.2015.08.004.Epub 2015 Oct 21.</ref> revealed interesting elements that call for a more in-depth analysis of the TMD phenomenon. The authors reported, in fact, that about 5-12% of the US population is affected by TMD and the annual cost of TMD management, excluding imaging costs, is about $4 billion. Interview Survey (NHIS) that included a total of 189,977 people, 4.6% (n = 8964) had temporomandibular joint and muscle disorders (TMJD).

We know by now that 'TMD' is the second most common chronic musculoskeletal condition after chronic low back pain<ref>Schiffman E, Ohrbach R, Truelove E, et al. Diagnostic criteria for temporomandibular disorders (DC/TMD) for clinical and research applications: recommendations of the International RDC/TMD Consortium Network* and orofacial pain special interest group†. J Oral Facial Pain Headache 2014;28(1):6–27</ref> and although Ahmad and Schiffman<ref name=":0" /> have exhaustively reported on the importance of imaging to make correct intra-articular diagnoses of TMJ, the doubt arises of the overlapping of symptomatic-clinical states as we have seen in the clinical cases reported in the previous chapters of Masticationpedia.

Rightly says Magda Krasińska-Mazur et al.<ref>Magda Krasińska-Mazur, Paulina Homel, Andrzej Gala, Justyna Stradomska, Małgorzata Pihut. Differential diagnosis of temporomandibular disorders - a review of the literature.Folia Med Cracov. 2022;62(2):121-137. doi: 10.24425/fmc.2022.141703.</ref> that the correct diagnosis of temporomandibular disorders is based on anamnesis and a thorough physical examination, as well as the results of additional tests.....but which ones?{{q2|What could be the best approach to TMDs patients?|.... we will present in this context a diagnostic model in the context of restoring the functional masticatory condition of the patient in question}}So far we have discussed many aspects that in some way delay the differential diagnosis in patients who report overlapping symptomatology and various clinical manifestations, a differential diagnosis that if, on the other hand, performed correctly and quickly could save the subject's life as happened to our 'Bruxer' and unfortunately not to our 'Balancer'. The doctor's forma mentis in these cases is fundamental and the decisive element remains that of stepping out of the 'specialist context' in order to take an indeterministic and probabilistic view of medicine at the same time. This is no different with regard to patients actually suffering from TMDs because there is no real neuro-gnathological discipline, the diagnosis as well as the therapy of these subjects remains the standard one, namely gnathological. The discipline of gnathology, although very valid, is also limited because it restricts the field of the 'observable' to the occlusal parameter, disregarding everything else that is part of the masticatory neuromotor network and beyond.<ref>Chiara Vompi, Emanuela Serritella, Gabriella Galluccio, Santino Pistella, Alessandro Segnalini, Luca Giannelli, Carlo Di Paolo. Evaluation of Vision in Gnathological and Orthodontic Patients with Temporomandibular Disorders: A Prospective Experimental Observational Cohort Study. J Int Soc Prev Community Dent PMID: 33042891 PMCID: PMC7523923 DOI: 10.4103/jispcd.JISPCD_273_19</ref> We will present this clinical case of a patient with DTMs to give a significant clinical diagnostic/therapeutic change in the field of 'Functional Neuro Gnathology' calling it, precisely, the NGF method.  

Figure 4 shows the neuromuscular responses of the silent period to chin percussion through a triggered neurological hammer when the patient was asked to clench her teeth maximally. If from a neurological point of view it is not possible to highlight elements referable to organic alterations of the _tCNS, some electrophysiological characteristics, however, are to be referred to a functional disorder of the system. In the upper trace, a decrease in the motor neuron reactivation phase can be seen immediately following the silent period. The possible neurophysiological mechanism capable of determining a similar decrease in facilitatory activities on the mandibular silent period can be ascribed to a change in the spindle motor drive induced by the input of muscle proprioceptors and nociceptors. The neuronal network of this process would take place through a loop formed by: muscle nociceptive afferents, the subnucleus caudalis of the V, inhibitory interneurons on static motor neurons and, as a last link, the modulation of the sensitivity of the neuromuscular spindles..<ref>Ro J.Y.,Capra  N.F.: Physiological evidence for caudal brainstem projections of jaw muscle spindle afferents.Exp.Brain Res 1999;128: 425-434</ref> <ref>Capra N.F.,Ro J.Y.: Experimental muscle pain produces central modulation of proprioceptive signals arising from jaw muscle spindles. Pain 2000; 86: 151-162.</ref><ref>Appelberg B.,Hulliger M.,Johansson H.Sojka P.: Actions on g-motoneurones elicited by electrical stimulation of group III muscle afferent fibers in the hind limb of the cat.J Physiol. 1983;335: 275-292.</ref><ref>Macefield  G.,Hagbarth E,Gorman R, Gandevia SC,, Burke D.: Decline in spindle support to a-motoneurones during sustained voluntary contractions.J.Physiol 1991;440:497-512.</ref><ref>Mense S.,Skeppar P.: Discharge behavior of feline gamma-motoneurones following induction of an  artificial myositis.Pain 1991; 46: 201-210.</ref><ref>Pedersen J, Ljubisavljevic M, Bergenheim M.,Johansson H.: Alterations in information trasmission  in ensembles  of primary muscle spindle afferents after muscle fatigue in heteronymous muscle.Neuroscience 1998;84: 953-959.</ref>  Also in this context the inhibitory component most likely prevails over the excitatory one and this could be ascribed to a malocclusion as we will see later. In particular, it can be noted the overlapping of the jaw jerk behavior, previously tested, in a path rectification condition. The arrow indicates the jaw jerk on all traces and the decrease in amplitude can be observed for the right masseter while it is relatively symmetrical on the temporal muscles.<br />

In figure 9c and 9d, we can see not only the well balanced centric contacts but above all the mediotrusive excursions. A few more words should be spent on this subject. Benedikt Sagl et al.<ref>Sagl B, Schmid-Schwap M, Piehslinger E, Rausch-Fan X, Stavness I. The effect of tooth cusp morphology and grinding direction on TMJ loading during bruxism. Front Physiol. 2022 Sep 15;13:964930. doi: 10.3389/fphys.2022.964930. eCollection 2022.PMID: 36187792 </ref> state, in their study in which the contribution of tooth inclination, medio-otrusive and laterotrusive excursion and von Mises stresses on the articular disc was analysed, that mediotrusive bruxing generates higher loads than laterotrusive simulations. In this sense it is not clear whether the mediotrusive contacts are a protective or a pejorative element in the generation of temporomandibular joint disorders. So much so that an article by Walton TR and Layton DM<ref>Walton TR, Layton DM. Mediotrusive Occlusal Contacts: Best Evidence Consensus Statement. J Prosthodont. 2021 Apr;30(S1):43-51. doi: 10.1111/jopr.13328.PMID: 33783093</ref> increases the confusion as they first state that the presence of TM interference in patient populations is large and varies from 0% to 77% and then conclude that TM interference should be avoided in any occlusal treatment regimen to minimize pulpal, periodontal, structural and mechanical complications or exacerbation of temporomandibular disorders (TMD). The confusion increases when he concludes that natural molar MT interferences should only be eliminated if signs and symptoms of TMD are present. The question that arises is the following

A study by Leitão AWA et al.<ref>Leitão AWA, Borges MMF, Martins JOL, Coelho AA, Carlos ACAM, Alves APNN, Silva PGB, Sousa FB. Celecoxib in the treatment of orofacial pain and discomfort in rats subjected to a dental '''occlusal''' '''interference''' model. Acta Cir Bras. 2022 Aug 15;37(5):e370506. doi: 10.1590/acb370506. eCollection 2022.PMID: 35976283</ref> is extraordinarily significant having objectively simulated the interference in the animal and histologically analyzed the changes in the trigmeinal ganglion contextually with the behavior of the animal when treated with or without selective cyclooxygenase 2 (COX-2) inhibitor. Furthermore, the authors treated the animals with a daily infusion of 0.1 ml/kg of saline (DOI+SAL) and 16 or 32 mg/kg of celecoxib (DOI+cel -8, -16, -32 ). They noted that animals subjected to masseter nociceptive stimulation and interference DOI + SAL showed an increase in isplateral (P < 0.001) and contralateral (P < 0.001) nociception, an increase in the number of bites (P = 0.010), scratching (P < 0.001) and grimacing scores (P = 0.032) while in the DOI+cel-32 group, these parameters were reduced.

Si-Yi Mo et al.<ref>Mo SY, Xue Y, Li Y, Zhang YJ, Xu XX, Fu KY, Sessle BJ, Xie QF, Cao Y. Descending serotonergic modulation from rostral ventromedial medulla to spinal trigeminal nucleus is involved in experimental occlusal interference-induced chronic orofacial hyperalgesia. J Headache Pain. 2023 May 10;24(1):50. doi: 10.1186/s10194-023-01584-3.PMID: 37165344 </ref> reinforces the above neuro-occlusal correlation by demonstrating that the descending pathway from serotonergic (5-HT) neurons in the rostral ventromedial medulla (RVM) to 5-HT3 receptors in the spinal trigeminal nucleus (Sp5), plays an important role in facilitating the maintenance of orofacial hyperalgesia after delayed removal of experimental occlusal interference (REOI).