Prevalence and correlation with sex, age, and dental status of bone apposition at the mandibular angle and radiographic alterations of the temporomandibular joints: a retrospective observational study in an adult Swiss population.

BACKGROUND: The purpose of this study was to determine the prevalence of radiographic changes in the mandibular angle (bone apposition) and osseous alterations in the temporomandibular joints (TMJs) in the adult population of Switzerland. In addition, the study intended to investigate possible correlations between the two sites of contour bone changes (mandibular angle and TMJ) and to analyze various patient-related factors, including sex, age, dental status, and medical history. METHODS: Panoramic radiographs of 600 patients distributed into six age groups (283 females, 317 males, aged 20 to 79 years) were included to evaluate radiographic changes. The bone in the mandibular angle region and the shape of the condylar heads were examined for contour changes (bone apposition at the jaw angles and osseous changes of the TMJs). General estimating equations, binormal tests, and chi-squared tests were used for statistical analysis. RESULTS: Approximately half of the mandibular angles (47.8%) showed bone apposition, mostly bilateral. TMJ alterations were less common (27%), often unilateral, with flattening being the most frequent finding. No significant correlation was found between the two sites. Bone apposition at the mandibular angle showed a significant male predominance, whereas TMJ changes did not differ by sex. Alterations in both sites increased with age, and were not related to dental status or analgesic use. CONCLUSIONS: Bone apposition at the mandibular angle should be interpreted as part of the natural functional adaptation of the bone associated with aging. Assuming that parafunctional habits may influence the development and progression of alterations in the mandibular angle or TMJs, the presence of radiographic changes in these areas should prompt dental clinicians to investigate further in this direction. TRIAL REGISTRATION: The study was approved by the Swiss Association of Research Ethics Committees (swissethics), BASEC reference number: 2020-00963 (25.05.2020).

Sex hormones associated with temporomandibular pain on palpation in male adolescents-Results of the epidemiologic LIFE child study.

OBJECTIVE: This study aimed to investigate whether the sex steroid precursor hormone dehydroepiandrosterone sulphate (DHEA-S), sex hormone-binding globulin (SHBG) and testosterone (TT) are associated with temporomandibular (TM) pain on palpation in male adolescents. METHODS: Out of the LIFE Child study dataset containing 1022 children and adolescents aged 10-18 years (496 males, 48.5%), we used a subsample of 273 male adolescents (mean age: 13.8 ± 2.3 years) in advanced pubertal development (PD) to analyse the association between hormones and TM pain. The Tanner scale was applied to describe the stage of PD. Pain on palpation of the temporalis and masseter muscles and the TM joints (palpation pain) was assessed using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Serum levels of sex hormones (DHEA-S, SHBG and TT) were determined using standardised laboratory analyses. Free TT was estimated from the ratio between TT and SHBG (free androgen index[FAI]). We calculated the risk of perceived positive palpation pain for male participants as a function of hormone levels (DHEA-S, FAI) taking into account age and body mass index (BMI). RESULTS: Among more developed (Tanner stage 4-5) male adolescents, 22.7% (n = 62) reported palpation pain in the TM region. In these participants, FAI levels were approximately half that of individuals without such pain (p < .01). DHEA-S levels were about 30% lower in the pain group (p < .01). In multivariable regression analyses, the odds ratio (OR) for pain on palpation decreased to 0.75 (95% confidence interval [CI]: 0.57-0.98) per 10 units of FAI level compared to those without pain, after controlling for the effects of age and adjusted BMI. We observed the same effect for this subgroup per unit of DHEA-S serum level (OR = 0.71; 95% CI: 0.53-0.94). CONCLUSION: At subclinical lower levels of serum free TT and DHEA-S, male adolescents are more likely to report pain on standardised palpation of the masticatory muscles and/or TM joints. This finding supports the hypothesis that sex hormones may influence pain reporting.

Number of occlusal contacts during maximum intercuspation in dentate adults: A systematised review.

BACKGROUND: Evaluating occlusal contacts during maximum intercuspation is one of the requirements for guiding clinicians during occlusal corrections and has been a topic of considerable importance for researchers over many decades. OBJECTIVE: This systematised review intends to evaluate the average number of occlusal contacts present in dentate adults, as documented within the dental literature over the past four decades (1980s-2022). METHODOLOGY: Electronic searches were conducted in three databases (PubMed, Livivo and Ovid) using a combination of search words. RESULTS: A total of 651 records were identified through PubMed and another 37 records through Livivo and Ovid databases. After eliminating duplicates and irrelevant records, 168 records were screened. Full texts of 61 articles remained, out of which 18 relevant papers that presented occlusal contacts in quantifiable value were considered. Various occlusal indicators, such as articulating paper, wax sheets, shimstock foil, impression material, gnathodynamometers and digital occlusal analysis systems, were used to evaluate occlusal contacts. The number of occlusal contacts widely ranged from 11 to 70. These variations likely depends upon the type and technique of occlusal indicator used, diversity among sampled populations and differing data collection procedures. CONCLUSION: Different methods of identifying occlusal contacts in the intercuspal position yield different numbers and patterns of contacts, depending on the nature and physical properties of the indicators used.

The human masseter muscle revisited: First description of its coronoid part.

INTRODUCTION: The masseter muscle is considered to be bilayered, consisting of a superficial and a deep part. However, a few historical texts mention the possible existence of a third layer as well, but they are extremely inconsistent as to its position. Here we performed an anatomical study to clarify the presence and morphological characteristics of a distinct third layer of the masseter muscle. MATERIALS AND METHODS: We dissected 12 formaldehyde-fixed human cadaver heads, analysed CTs of 16 fresh cadavers, evaluated MR data from one living subject and examined histological sections using methyl methacrylate embedding of one formaldehyde-preserved head. RESULTS: An anatomically distinct, deep third layer of the masseter muscle was consistently demonstrated, running from the medial surface of the zygomatic process of the temporal bone to the root and posterior margin of the coronoid process. Ours is the first detailed description of this part of the masseter muscle. CONCLUSIONS: To facilitate discussion of this newly described part of the masseter, we recommend the name M. masseter pars coronoidea (coronoid part of the masseter) as a further reference. The arrangement of its muscle fibers suggest it being involved in stabilising the mandible by elevating and retracting the coronoid process.

Bone apposition at the mandibular angles as a radiological sign of bruxism: a retrospective study.

BACKGROUND: The main objective of this investigation was to determine on panoramic radiographs the prevalence of macroscopically visible alterations (bone apposition in combination with directional change) in the mandibular angle region in bruxism patients. Another aim was to describe and detect different morphological characteristics of the jaw angles. METHODS: Two hundred panoramic radiographs were studied: 100 images of adults with clinically diagnosed bruxism (73 women, 27 men, age range 21-83 years), 100 images of a comparison group consisting of adolescents (66 girls, 34 boys, age range 12-18 years). RESULTS: The morphological changes of the 400 jaw angles could be classified into four degrees. In the adult group, almost half of mandibular angles showed bone apposition. Conversely, the prevalence in the control group was zero. The localization of the appositions corresponds to the insertions of the masseter and medial pterygoid muscles at the mandibular angle. CONCLUSIONS: The bone apposition at the mandibular angles should be interpreted as a functional adaptation to the long-term increased loads that occur during the contraction of the jaw closing muscles due to bruxism. Hence, radiologically diagnosed bone apposition may serve as an indication or confirmation of bruxism.

Centric relation critically revisited-What are the clinical implications?

PURPOSE OF THE ARTICLE: Centric relation is a dental term that has undergone many alterations over the years, which in turn have led to significant clinical controversies. These continuing changes in the meaning of the term CR have not only led to confusion, but they also have resulted in a variety of unnecessary diagnostic and therapeutic procedures. Analysis of the dental literature reveals ongoing misunderstanding and disagreement regarding that term among both clinicians and academic dentists. MATERIALS AND METHODS: A search of the PubMed database was performed with the following search terms: "centric relation", "masticatory muscles", "maxillomandibular relationship" and "condylar position." Relevant literature from the past 70 years until the present day was meticulously scrutinised. RESULTS: As expected, the literature review on the topic of CR revealed a problematic pattern of changing definitions and clinical disagreements, all of which have had a significant impact on the practice of dentistry. CONCLUSION: There are semantic, conceptual and practical reasons for concluding that the term 'centric relation' is flawed. Those flaws have a significant impact on dental practice. Based on our analysis, argumentation is provided to conclude that the term 'centric relation' should be abandoned. Instead, it appears that every individual has a unique temporomandibular joint relationship which cannot be described by any singular term. In healthy dentate patients, this relationship is determined by the maximum intercuspation of the teeth and should therefore be considered as biologically acceptable.

["A picture is worth a thousand words " : Diagnosis of orofacial pain using Dolografie®]. / "Ein Bild sagt (noch) mehr " : Diagnostik orofazialer Schmerzen mittels Dolografie®.

BACKGROUND: Since 2017, the diagnosis of patients with orofacial pain at the University Center for Dental Medicine Basel has been supplemented by using standardized image graphics (Dolografie® [Affolter/Rüfenacht, Bern, Switzerland]). For this purpose, patients select from a set of 34 cards those that visually best match their pain and then explain the reason for their choice. OBJECTIVES: (1) How many cards are selected on average? (2) Do sex and age influence the choice of cards? (3) Are there preferences in the choice of cards? (4) Are there correlations between pain diagnostic categories (e.g., musculoskeletal versus neuropathic orofacial pain) and the cards selected? (4) Are there correlations between pain diagnostic categories (e.g., musculoskeletal versus neuropathic orofacial pain) and the selected cards? METHODS: The available complete pain anamnestic data of 143 patients were evaluated. RESULTS: (1) Patients selected an average of 3.5 cards to describe their pain. Up to six cards were sufficient for a detailed description of pain in almost all patients. With the 16 most frequently chosen cards, the majority of patients were able to adequately describe their pain. (2) Sex and age had no influence on the number of selected cards. (3) There were clear preferences: Card 02 was chosen most often (45 times), followed by cards 05 and 13 (27 times each). (4) A differentiating choice was made most clearly in neuropathic pain by a strong preference for card 28 and a disregard of card 18. CONCLUSION: The use of standardized image cards as a "visual communication tool" has proven to be a time-efficient procedure in the context of history taking, which helps to obtain clinically relevant information not previously expressed by the patient.

Influence of Coca-Cola on orthodontic materials. A systematic review.

This analysis was conducted to assess the impact of Coca-Cola on orthodontic materials compared to that of other fluids. Electronical searches were carried out in PubMed, Livivo, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov, supplemented by manual searches in the reference lists of the articles selected for full text evaluation. The risk of bias was assessed on the basis of a "risk of bias summary." A total of 216 bibliographic summaries of articles were obtained, eleven of which were relevant. Nine of these papers showed a low risk, while two publications from one in vivo study exhibited a high risk of bias. The continuing influence of Coca-Cola caused significant discoloration of elastomeric materials and resulted in significantly lower shear bond strength of the brackets and higher corrosion. With regard to orthodontic appliances, additional in situ and in vivo studies are desirable. Special attention should be paid to an appropriate number of samples or patients, as most investigations lacked a sufficient number of test subjects. In addition, investigations with long observation periods and documented beverage consumption should be preferred. The intake of cola-containing beverages during orthodontic therapy and the exposure duration of these beverages to orthodontic material should be reduced to a minimum, as this can impair the adhesive strength and lead to corrosion of orthodontic brackets. The interval between orthodontic appointments should be short to avoid discoloration of orthodontic elastomeric ligatures.

Maximum mandibular mobility in patients with temporomandibular disorders.

Assessment of mandibular mobility is an integral part of many dental examinations. Yet, information on the maximum range of mandibular motion in large groups of patients with temporomandibular disorders (TMDs) is limited. Therefore, we analyzed the corresponding data of 500 TMD patients who had presented at the University Center for Dental Medicine Basel. All measurements had been carried out by one examiner. The average maximal values for unassisted jaw opening, protrusion, and movement to the right and left were 49.3 mm (SD: 9.1), 8.8 mm (SD: 2.3), 9.4 mm (SD: 2.5), and 11.8 mm (SD: 3.1), respectively. Since activities such as chewing, talking, oral hygiene or even yawning require neither very wide openings nor extensive lateral or protrusive excursions, we would like to propose the following general threshold values for impaired mandibular function: maximum interincisal distance < 30 mm; maximum laterotrusion as well as maximum protrusion < 5 mm. These cut-off values, which are lower than those traditionally suggested in the dental literature, appear to be sufficient to carry out functionally undisturbed mandibular movements. By lowering the traditionally higher thresholds, the spectrum of anatomical and functional variability is increased. In this way, patients and non-patients may be protected against medicalization, overdiagnosis, and overtreatment.

Facial pain ­ an interdisciplinary challenge / Neuropathische Gesichtsschmerzen ­ eine interdisziplinäre Herausforderung

Acute pain has a warning function and is necessary to survive. Conversely, chronic or recurrent pain is a pathological entity itself and has tremendous impact on the quality of life of the patients . Facial pain is very common and can have various causes. The trigeminal nerve innervates the face, and tumours along its intracranial way as well as peripheral injury can lead to facial pain. Also, infections and systemic diseases, like multiple sclerosis, may cause pain in the face, so can vascular compressions of the trigeminal or glossopharyngeal nerve. Detailed pain history is crucial in order to rule out other than dental reasons for facial pain before invasive dental therapy is initiated. A multidisciplinary approach and additional imaging modalities might be necessary to find the optimal treatment for the patient.

Occlusal dysesthesia-A clinical guideline.

BACKGROUND: The diagnosis and management of patients suffering from occlusal dysesthesia (OD) remain a major challenge for dental practitioners and affected patients. OBJECTIVES: To present the results of a literature-based expert consensus intended to promote better understanding of OD and to facilitate the identification and management of affected patients. METHODS: In 2018, electronic literature searches were carried out in PubMed, Cochrane Library and Google Scholar as well as in the archives of relevant journals not listed in these databases. This approach was complemented by a careful assessment of the reference lists of the identified relevant papers. The articles were weighted by evidence level, followed by an evaluation of their contents and a discussion. The result represents an expert consensus. RESULTS: Based on the contents of the 77 articles identified in the search, the current knowledge about clinical characteristics, epidemiology, aetiology, diagnostic process, differential diagnosis and management of OD is summarised. CONCLUSIONS: Occlusal dysesthesia exists independently of the occlusion. Instead, it is the result of maladaptive signal processing. The focus should be on patient education, counselling, defocusing, cognitive behavioural therapy, supportive drug therapy and certain non-specific measures. Irreversible, specifically an exclusively dental treatment approach must be avoided.

[Screening for temporomandibular disorders : A sensible approach?] / Screening für kraniomandibuläre Dysfunktionen : Eine sinnvolle Maßnahme?

BACKGROUND: Temporomandibular disorders (TMDs) are typically characterized by pain in the masticatory muscles and temporomandibular joints (TMJs) and by limitation of mandibular mobility. In June 2019, the German Society of Craniomandibular Function and Disorders presented a screening tool to identify individuals with TMDs. The assessment tool consists of patient history (three questions related to jaw pain, one question related to impaired mandibular mobility) and a clinical examination (palpation of masticatory muscles and TMJs; evaluation of maximum jaw opening; assessment of the presence of occlusal disturbances; documentation of TMJ noises). OBJECTIVES: The present article focusses on two questions: (1) Which of the nine parts of the tool are appropriate, and which are not? (2) In general, can screening for TMDs be recommended? CONCLUSION: While the anamnestic questions, as well as the assessment of maximum mandibular opening, reflect the clinically relevant symptoms and signs of TMD patients, the remaining four clinical measures do not. Furthermore, TMD screening for painful TMDs appears unnecessary because patients suffering from orofacial pain and/or restricted mandibular mobility are likely to consult a therapist by themselves. Therefore, the use of this screening tool may lead to overdiagnosis, possibly resulting in nonindicated diagnostic and therapeutic measures.

Prevalence of temporomandibular disorders in patients seeking orthodontic treatment: A systematic review.

The objective of this systematic review was (a) to establish the prevalence of temporomandibular disorders (TMDs) in patients seeking orthodontic treatment and (b) to determine the association between the presence of TMD and sex, age and malocclusion. A systematic literature search was performed according to PRISMA guidelines from 1969 to 2019 using the PubMed and LIVIVO databases. Eight study articles met the inclusion and exclusion criteria. An additional three contributions were identified through manual searching of the reference lists of retrieved articles. The methodological quality of the 11 articles was assessed with the Joanna Briggs Institute Critical Appraisal Checklist for prevalence studies. TMD prevalence ranged from 21.1% to 73.3%. The frequency of painful TMD signs/symptoms varied from 3.4% to 65.7%, while non-painful signs/symptoms ranged from 3.1% to 40.8%. The percentage of males and females presenting with TMD varied from 10.6% to 68.1% and 21.2 to 72.4%, respectively. In all studies, TMD prevalence was higher among females. The majority of articles reported more TMD signs/symptoms in individuals older than 18 years as compared to younger ones (≤18 years). While in four studies no association between TMD and malocclusion was found, another three investigations indicated that TMD may be related to certain occlusal traits. The TMD prevalence in patients seeking orthodontic treatment was high, with many individuals presenting painful TMD signs/symptoms. Female and older patients appear to have a greater occurrence of TMD. Although no strong association between TMD and malocclusion was established, several occlusal traits were implicated.

Risk factors for bruxism

The aim of the present study was to summarize the risk factors for bruxism that were identified by a systematic search of the literature published between 2007 and 2016. Depending on the size of the odds ratios (ORs) and the lower limit of the 95% confidence intervals indicated by the reports, four risk categories were differentiated. Among others, emotional stress, consumption of tobacco, alcohol, or coffee, sleep apnea syndrome, and anxiety disorders were recognized as important factors among adults. In children and adolescents, apart from distress, behavioral abnormalities and sleep disturbances predominated. Knowledge of the identified risk factors may be useful when taking the medical history of bruxing patients. Although many of the described variables cannot be influenced by prophylactic or therapeutic means, we recommend the following patient-centered approach ("SMS therapy"): self-observation, muscle relaxation, stabilization (Michigan) splint.

Reliability and Validity of the Diagnostic Criteria for Temporomandibular Disorders Axis I in Clinical and Research Settings: A Critical Appraisal.

The recently published Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) Axis I, which is recommended for use in clinical and research settings, has provided an update of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The authors of the DC/TMD based their publication on the results of a Validation Project (2001-2008) and consecutive workgroup sessions held between 2008 and 2013. The DC/TMD represents a major change in both content and procedures; nonetheless, earlier concerns and new insights have only partly been followed up when drafting the new recommendations. Moreover, the emphasis on immediate implementation in clinical and research settings is not in line with the provided external evidence on which the DC/TMD is based. This Focus Article describes these concerns with regard to several aspects of the DC/TMD: the additional classification categories; the high dependency on pressure-pain results from use of the recommended palpation technique; the TMD pain screening instrument; the test population characteristics; the utility of additional subgroups; the use of a reference standard; the dichotomy between pain and dysfunction; and the DC/TMD algorithms. Thus, although the DC/TMD represents an improvement over the RDC/TMD, its immediate implementation in research and clinical care does not yet appear to be adequately substantiated.

Authors' Response to Critical Commentaries: Reliability and Validity of the DC/TMD Axis I.

No abstract available.