Transitioning to chronic temporomandibular disorder pain: A combination of patient vulnerabilities and iatrogenesis

Effects of orthodontic aligners on 24-hour masseter muscle activity: a multiple-day electromyographic study

OBJECTIVE

This study aimed to assess the effects of aligners on masseter muscle activity by using an electromyographic device in the home environment.

METHODS

The study was performed on healthy patients who required orthodontic treatment. Three different 24 h-EMG recording sessions were performed in different conditions: without aligners, with passive aligners, and with active aligners. The non-functional MMA work index (nfMMA-WI) and the non-functional MMA time index (nfMMA-TI) for both awake and sleep hours were assessed. ANOVA test was used to compare the average activity during the three recording conditions.

RESULTS

On average, a total recording time of 204.7 ± 7.9 hours were provided for each patient. For most patients, ANOVA test showed an absence of significant differences between the recording sessions.

CONCLUSIONS

The impact of our results is not negligible: clinicians can find remarkable support to the hypothesis that the use of aligners affects the MMA only in a minority of subjects.

The Nocebo Effect: A Bias in Clinical Practice-An Ethical Approach

BACKGROUND

The nocebo effect is often disregarded in medical practice and is certainly much less known than the placebo effect, although, in reality, both can influence therapeutic decision making and the quality of life of patients. However, the nocebo effect raises a number of issues not only of a practical nature related to clinical activity but also ethical dilemmas related to the observance of the patient's autonomy, nonmaleficence, or informed consent and the information on which it is based.

AREAS OF UNCERTAINTY

The ethical dilemmas raised by the nocebo effect revolve around how informed consent can be achieved, the accuracy and volume of information that is transmitted to the patient, and how to report negative side effects of therapeutic treatment.

DATA SOURCES

In September 2023, a narrative analysis of the literature was conducted using a combination of keywords such as nocebo, placebo, ethics, therapeutic relationship from PubMed, Scopus, Google Scholar, and so on, as well as from official documents developed at an international level (World Health Organization), for a period of 10 years (2012-2021).

RESULTS

Analyzing the articles that remarked upon the significant impact of ethics in nocebo research or in the therapeutic relationship, we can state that the existence of several relevant issues of interest have been detected regarding the ethical use of nocebo and its impact in research or in clinics and thus the need for proper knowledge and management of the impact of nocebo effects. The ethical paradox of obtaining informed consent with the 2 goals, first, the need for complete information and second, the preservation of the autonomy of the patient, respectively, that of "primum non-nocere" and of avoiding unnecessary harm by revealing probable adverse effects is a point of interest for numerous studies. The potential for a nocebo effect is present when we inform patients about the risks and benefits of treatment, there being a clear link between the moral and ethical duty to inform patients and the need to avoid situations that increase the nocebo impact on how the disease or the adverse effects of the treatment are perceived. Adapting information about the side effects of medicines should focus on ensuring a balance between transparency and caution, especially in patients with a high potential for nocebo effect.

CONCLUSIONS

The nocebo effect had for a long time been unknown or denied, although it can interfere with the results of the treatment used. As the nocebo phenomenon becomes increasingly known in medical practice, the clinical and ethical implications are identified by medical staff, and nocebo's adverse responses are no longer ignored.

Accuracy of temporomandibular disorders diagnosis evaluated through the diagnostic criteria for temporomandibular disorder (DC/TDM) Axis II compared to the Axis I evaluations: a systematic review and meta-analysis

BACKGROUND

The temporomandibular joint (TMJ) is a complex joint that facilitates mandibular movements during speech, chewing, and swallowing activities. The Axis I evaluation of the DC/TMD focuses on assessing physical diagnoses related to TMDs. It includes an assessment of pain and functional limitations, such as jaw opening range, joint sounds, and joint tenderness. The Axis II evaluation of the DC/TMD provides information on the patient's psychological status and quality of life. This Systematic Review with Meta-Analysis aimed to evaluate the accuracy of Temporomandibular Disorders diagnosis considered through the Diagnostic Criteria for Temporomandibular Disorder (DC/TDM) axis II compared to the Axis I evaluations.

METHODS

A search was made in PubMed, Web of Science and Lilacs for articles published from the inception until 20 January 2023. We applied the Population, Exposure, Comparator, and Outcomes (PECO) model [1] to assess document eligibility. Only studies that evaluated patients by DC/TMD Axis I and Axis II were considered. Review Manager version 5.2.8 (Cochrane Collaboration) was used for the pooled analysis. We measured the odds ratio (OR) between the two groups (Axis I and Axis II).

RESULTS

Fifty-one articles were selected because of the search. Four papers were excluded before the screening: 2 pieces were not in English, and two were reviewed. The remaining 47 articles were selected for the title and abstract screening to evaluate whether they met the PECO criteria. Among these, four papers were established; the overall effect showed that there was no difference in TMD diagnosis between Axis I and Axis II (RR 1.17; 95% CI: 0.80- 1.71; Z:0.82; P = .41), suggesting that there is no difference between Axis I and Axis II.

CONCLUSION

In conclusion, DC/TMD is an effective tool for the diagnosis of TMD. It improves the accuracy of TMD diagnosis, allows for the classification of subtypes, and assesses psychosocial factors that may impact the development or maintenance of TMD symptoms.

A critical look at outcome measures: Comparison between four dental research journals by use of a hierarchical model

AIM

To assess the status quo of outcome measures used in treatment studies in Endodontics, and potentially identify strategies for improvement, by (i) systematically assessing the outcome measures using a conceptual model and (ii) comparing these with measures used in corresponding studies in the adjacent fields.

METHODOLOGY

The International Endodontic Journal, Caries Research, The Journal of Clinical Periodontology and The Journal of Oral & Facial Pain and Headache were selected to cover four adjacent dental disciplines. In each journal, the 50 most recent consecutive publications fulfilling inclusion criteria were included. A hierarchical model for diagnostic imaging studies was modified to assess studies related to treatment. The model comprised six levels, with technical as the lowest level and societal as the highest. Extracted data included study origin, study type, and identified outcome measures. Fisher's Exact Tests with Bonferroni corrections compared studies. p < .05 was considered statistically significant.

RESULTS

Amongst 756 publications, the 200 most recent studies matching the inclusion criteria were identified. Less than half (36.5%) assessed the clinical, patient, or societal aspects of treatment; 10.0% in International Endodontic Journal, 28.0% in Caries Research, 38.0% in Journal of Clinical Periodontology, and 70.0% in Journal of Oral & Facial Pain and Headache (p < .001).

CONCLUSIONS

According to included publications, research on treatment within the endodontic field is mainly focusing on technical and biological outcomes. The benefits of patients and society were less frequently examined than in corresponding journals in adjacent disciplines. When designing studies, including higher-level outcomes should be considered.

Research routes on awake bruxism metrics: Implications of the updated bruxism definition and evaluation strategies

BACKGROUND

With time, due to the poor knowledge on it epidemiology, the need to focus on awake bruxism as a complement of sleep studies emerged.

OBJECTIVE

In line with a similar recent proposal for sleep bruxism (SB), defining clinically oriented research routes to implement knowledge on awake bruxism (AB) metrics is important for an enhanced comprehension of the full bruxism spectrum, that is better assessment and more efficient management.

METHODS

We summarised current strategies for AB assessment and proposed a research route for improving its metrics.

RESULTS

Most of the literature focuses on bruxism in general or SB in particular, whilst knowledge on AB is generally fragmental. Assessment can be based on non-instrumental or instrumental approaches. The former include self-report (questionnaires, oral history) and clinical examination, whilst the latter include electromyography (EMG) of jaw muscles during wakefulness as well as the technology-enhanced ecological momentary assesment (EMA). Phenotyping of different AB activities should be the target of a research task force. In the absence of available data on the frequency and intensity of wake-time bruxism-type masticatory muscle activity, any speculation about the identification of thresholds and criteria to identify bruxers is premature. Research routes in the field must focus on the improvement of data reliability and validity.

CONCLUSIONS

Probing deeper into the study of AB metrics is a fundamental step to assist clinicians in preventing and managing the putative consequences at the individual level. The present manuscript proposes some possible research routes to advance current knowledge. At different levels, instrumentally based and subject-based information must be gathered in a universally accepted standardised approach.

Neuroimaging and artificial intelligence for assessment of chronic painful temporomandibular disorders-a comprehensive review

Chronic Painful Temporomandibular Disorders (TMD) are challenging to diagnose and manage due to their complexity and lack of understanding of brain mechanism. In the past few decades' neural mechanisms of pain regulation and perception have been clarified by neuroimaging research. Advances in the neuroimaging have bridged the gap between brain activity and the subjective experience of pain. Neuroimaging has also made strides toward separating the neural mechanisms underlying the chronic painful TMD. Recently, Artificial Intelligence (AI) is transforming various sectors by automating tasks that previously required humans' intelligence to complete. AI has started to contribute to the recognition, assessment, and understanding of painful TMD. The application of AI and neuroimaging in understanding the pathophysiology and diagnosis of chronic painful TMD are still in its early stages. The objective of the present review is to identify the contemporary neuroimaging approaches such as structural, functional, and molecular techniques that have been used to investigate the brain of chronic painful TMD individuals. Furthermore, this review guides practitioners on relevant aspects of AI and how AI and neuroimaging methods can revolutionize our understanding on the mechanisms of painful TMD and aid in both diagnosis and management to enhance patient outcomes.

Centric relation-A biological perspective of a technical concept

BACKGROUND

Few terms and concepts have been so extensively debated in dentistry as the words 'centric relation' (CR). Debates involve its biological, diagnostic and therapeutic usefulness.

METHODS

A review of the literature on the current concepts on CR as a diagnostic or therapeutic aid in dentistry was provided. Clinical trials assessing the superiority of one CR recording method over the others to identify patients with temporomandibular disorders (diagnostic use) or to manage patients with prosthodontic or orthodontic needs (therapeutic use) were tentatively included.

RESULTS

Due to the absence of literature addressing either of the above targets, a comprehensive overview was provided. The diagnostic use of CR as a reference position to identify the correct position of the temporomandibular joint condyle within the glenoid fossa is not supported and lacks anatomical support. From a therapeutic standpoint, the use of CR can be pragmatically useful in prosthodontics as a maxillo-mandibular reference position when occlusal re-organization is warranted and/or when the position of maximum intercuspation is no longer available.

CONCLUSIONS

The derived occlusal goals from a diagnostic misuse of CR are generally the result of circular reasoning, that is a technique is based on the recording of a certain condylar position that is believed to be 'ideal' and the treatment is considered successful when such position is shown by the specific instrument that was manufactured for that purpose. The term 'Centric Relation' might be replaced with the term 'Maxillo-Mandibular Utility Position'.

Temporomandibular Disorders as Contributors to Primary Headaches: A Systematic Review

AIMS

To systematically review the literature assessing associations between TMDs and primary headaches.

METHODS

Using validated clinical criteria, studies on TMDs and primary headaches published up to January 10, 2023 were identified using six electronic databases. This review adhered to the PRISMA 2020 guidelines and 27-item checklist and is registered on PROSPERO (CRD42021256391). Risk of bias was evaluated using the National Institutes of Health Quality Assessment Toolkits for Observational Cohort and Cross-Sectional Studies.

RESULTS

Two independent investigators rated 7,697 records against the primary endpoint and found 8 records meeting the eligibility requirements. Migraine was found to be the most common primary headache related to TMDs (61.5%), followed by episodic tension-type headache (ETTH; 38.5%). A moderate association was found for mixed TMDs with migraine and ETTH, with a large sample size and multiple studies included (n = 8). A very low-quality association was found for myalgia-related TMDs with migraine and ETTH (included studies, n = 2).

CONCLUSION

The association between TMDs and primary headaches is of great interest given the possible effectiveness of TMD management in reducing headache intensity/frequency in patients with TMDs and headache comorbidity. A moderate association was found for mixed TMDs with primary headaches, in particular migraine and ETTH. However, owing to the overall moderate certainty of evidence of the present findings, further longitudinal studies with larger samples investigating possible associated factors and using accurate TMD and headache category assignment are needed.

Overtreatment "Successes"--What Are the Negative Consequences for Patients, Dentists, and the Profession?

AIMS

To describe how some management practices in the field of orofacial musculoskeletal disorders (also described as temporomandibular disorders [TMDs]) are based on concepts about occlusal relationships, condyle positions, or functional guidance; for some patients, these procedures may be producing successful outcomes in terms of symptom reduction, but in many cases, they can be examples of unnecessary overtreatment.

METHODS

The authors discuss the negative consequences of this type of overtreatment for both doctors and patients, as well as the impact on the dental profession itself. Special focus is given to trying to move the dental profession away from the old mechanical paradigms for treating TMDs and forward to the more modern (and generally more conservative) medically based approaches, with emphasis on the biopsychosocial model.

RESULTS

The clinical implications of such a discussion are apparent. For example, it can be argued that the routine use of Phase II dental or surgical treatments for managing most orofacial pain cases represents overtreatment, which cannot be defended on the grounds of symptom improvement (ie, "successful" outcomes) alone. Similarly, there is enough clinical evidence to conclude that complex biomechanical approaches focusing on the search for an ideal specific condylar or neuromuscular position for the management of orofacial musculoskeletal disorders are not needed to produce a positive clinical result that is stable over time.

CONCLUSION

Typically, overtreatment successes cannot be easily perceived by the patients or the treating dentists because the patients are satisfied and the dentists feel good about those outcomes. However, neither party knows whether an excessive amount of treatment has been provided. Therefore, both the practical and ethical aspects of this discussion about proper treatment vs overtreatment deserve attention.

Prevalence of Temporomandibular Disorders Based on a Shortened Symptom Questionnaire of the Diagnostic Criteria for Temporomandibular Disorders and Its Screening Reliability for Children and Adolescents Aged 7-14 Years

The prevalence and adequacy of diagnostic approaches for temporomandibular disorders (TMD) in children and adolescents are still matters of debate. This study aimed to determine the prevalence of TMD and oral habits in children and adolescents aged 7-14 years and evaluate the consistency between self-reported TMD symptoms and clinical findings using a shortened Axis I of Diagnostic Criteria for TMD (DC/TMD). Children (aged 7-10) and adolescents (aged 11-14) of both sexes were invited to participate in this study (n = 1468). Descriptive statistics for all observed variables and Mann-Whitney U-Tests for the clinical examination were performed. A total of 239 subjects participated in the study (response rate 16.3%). The self-reported prevalence of TMD was found to be 18.8%. The most frequently reported oral habit was nail biting (37.7%), followed by clenching (32.2%) and grinding (25.5%). Self-reported headache increased with age, while clenching and grinding decreased. Based on the answers to the DC/TMD Symptom Questionnaire, subgroups of asymptomatic and symptomatic participants (n = 59; 24.7%) were established and randomly selected for the clinical examination (f = 30). The shortened Symptom Questionnaire showed a sensitivity of 0.556 and a specificity of 0.719 for pain during the clinical examination. Although the Symptom Questionnaire exhibited high specificity (0.933), its sensitivity (0.286) for temporomandibular joint sounds was low. Disc displacement with reduction (10.2%) and myalgia (6.8%) were the most common diagnoses. In conclusion, the self-reported prevalence of TMD in children and adolescents in this study was comparable to that reported in the literature for adults. However, the accuracy of the shortened Symptom Questionnaire as a screening tool for TMD-related pain and jaw sounds in children and adolescents was found to be low.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2021 dental literature in restorative dentistry to inform busy dentists regarding noteworthy scientific and clinical progress over the past year. Each member of the committee brings discipline-specific expertise to coverage of this broad topical area. Specific subject areas addressed, in order of the appearance in this report, include COVID-19 and the dental profession (new); prosthodontics; periodontics, alveolar bone, and peri-implant tissues; implant dentistry; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence daily dental treatment decisions with an emphasis on future trends in dentistry. With the tremendous volume of dentistry and related literature being published daily, this review cannot possibly be comprehensive. Rather, its purpose is to update interested readers and provide important resource material for those interested in pursuing greater details on their own. It remains our intent to assist colleagues in negotiating the extensive volume of important information being published annually. It is our hope that readers find this work useful in successfully managing the patients and dental problems they encounter.

Gut Bless Your Pain—Roles of the Gut Microbiota, Sleep, and Melatonin in Chronic Orofacial Pain and Depression

Background. Increased attention has been paid to the gut–brain axis recently, but little is known so far regarding how this translates into pain susceptibility. Aim. The aim of this review is to determine whether gastroenterological disorders and sleep disorders (directly or indirectly) contribute to an increased susceptibility to depression and chronic orofacial pain. Method. A search was performed in the U.S. National Library of Medicine (PubMed) database in order to find studies published before 19 December 2021. We used the following terms: gut microbiome, OR sleep quality, OR melatonin, OR GERD, OR IBS, AND: depression OR chronic pain, in different configurations. Only papers in English were selected. Given the large number of papers retrieved in the search, their findings were described and organized narratively. Results. A link exists between sleep disorders and gastroenterological disorders, which, by adversely affecting the psyche and increasing inflammation, disturb the metabolism of tryptophan and cause excessive microglial activation, leading to increased susceptibility to pain sensation and depression. Conclusions. Pain therapists should pay close attention to sleep and gastrointestinal disorders in patients with chronic pain and depression.

Measuring Changes in Jaw Opening Forces to Assess the Degree of Improvement in Patients with Temporomandibular Disorders

Background: Currently, the degree of improvement in patients with TMDs is measured through subjective questionnaires and clinical examination This study aimed to investigate the properties of an objective quantitative measure of jaw-opening forces to assess clinical improvement in temporomandibular disorder (TMD) patients following treatment. Methods: Baseline jaw-opening forces were recorded for TMD-patients (n = 62) and a comparison group of TMD-free participants (n = 56), using a jaw-opening forces measuring device. TMD patients were divided into three subcategories (myofascial pain, disc-displacement, and myofascial pain and disc-displacement combined) and received a combination of treatment for six months; meanwhile, TMD-free participants did not receive treatment. Jaw-opening forces for each participant in both groups were measured at their six-month review appointment. Results: Jaw-opening forces were reliable at baseline (single measure ICC 0.98, 95% CI 0.97–0.98, ICC ≥ 0.94 for all groups and subcategories). Jaw-opening forces increased in the TMD group following treatment at six-months (18.6 N at baseline and 32.4 N at six-months, p < 0.001) and did not change significantly in the TMD-free group (49 N at baseline and 48.3 N at six-months). There was a small improvement in the disc displacement group (27.8% higher forces, p = 0.002). However, the myofascial-pain and myofascial-pain-and-disc-displacement groups showed significant improvement following treatment (93.5% higher forces, p < 0.001; 91.1% higher forces, p < 0.001; respectively). Conclusion: This study demonstrated that the measurement of jaw-opening forces could potentially be used to assess the clinical improvement in TMD patients following diagnosis and treatment.

Ultrasound Imaging of Head/Neck Muscles and Their Fasciae: An Observational Study

Background: Masticatory muscle thickness provides objective measurements of the temporomandibular motor function, which may change in patients with oral myofascial pain. Moreover, they are considered as being part of the craniocervical unit by a crucial relationship with cervical muscles and their fasciae. In this study, we aimed to assess by ultrasound (US) imaging the fasciae of the masseter, temporal, and sternocleidomastoid muscles to understand their mean thickness and eventual variation in relationship with the muscles, sides, and sex.

Methods: We studied 16 healthy volunteers without temporomandibular joint dysfunction. Concerning each subject were evaluated the range of motion of the temporomandibular joint and of the neck, the thickness of muscles and their fasciae of both sides, and the delta of muscle thickness.

Results: All the motor evaluations of the subjects showed normal ranges. The US results showed that the fasciae have a mean thickness of 0.50 ± 0.1 mm, which did not change during muscle contraction. The evaluated muscles presented a symmetry between right and left (p > 0.05), even if the delta of muscle (US) thickness had a huge range between different subjects, for example in the masseter muscle from 0.7 to 4.2 mm.

Conclusions: Ultrasound imaging is a suitable and reliable tool to study the muscles and fasciae of the head and neck region, permitting also the evaluation of the ability of the muscles to contract. Finally, identifying functional asymmetry that could become symptomatic, US imaging could allow an early rehabilitation treatment.