Temporomandibular disorders assessment: medicolegal considerations in the evidence-based era

Relationship between natural or iatrogenic malocclusions and temporomandibular disorders: A case control study

OBJECTIVE

To investigate the link between malocclusions and temporomandibular disorders (TMD) with a focus on iatrogenic malocclusion. Other etiologies of TMD (oral parafunctions) were also assessed.

METHODS

The prevalence of malocclusions was correlated in two groups: patients with TMD (case group) and patients without TMD (control group). Malocclusions involving dental care were specified. Parafunctions in the case group were assessed.

RESULTS

A statistically significant association between TMD and overbite >4 mm, interferences in laterotrusion, and absence of Angle Class I was shown. A potential deleterious effect of iatrogenic malocclusions was highlighted.

CONCLUSION

The multifactorial etiology of TMD was confirmed because an association between TMD and three malocclusions was found, and all case patients had parafunction(s). Current recommendations advising first a reversible treatment, TMD care should start with a behavioral re-education to remove parafunctions. However, it is essential to avoid creating iatrogenic malocclusion during dental care.

Current thinking about medicolegal aspects of temporomandibular joint surgery

This paper considers the current situation regarding medicolegal risks in temporomandibular joint surgery from three perspectives: the law, the patient, and the surgeon. The law relating to successful claims of clinical negligence requires that a cause-and-effect relationship is demonstrated by the claimant. Complications are considered in the light of recent research on their stratification in other fields of surgery. Surgeons become repeat offenders rarely. They display certain common characteristics which are discussed in this paper.

Additional splint therapy has no superiority in myogenic temporomandibular disorders: A systematic review and meta-analysis of randomized controlled trials

Purpose Temporomandibular disorders (TMDs) are frequent stomatological disorders. However, their treatment is controversial. Therefore, we compared the efficacy of combination therapy (splint therapy along with physiotherapy, manual therapy, and counseling) with physiotherapy, manual therapy, and counseling alone. The extent of mouth opening and pain perception were the outcomes.Study selection Systematic searches for English publications were performed using four major literature databases (Cochrane Library, EMBASE, PubMed, and Web of Science). We included randomized controlled trials. We calculated mean differences with 95% confidence interval (CI) for pain perception and maximum mouth opening (MMO) for the two groups. The Hartung-Knapp adjustment was used for cases comprising at least five studies.Results Six articles were included in the pain perception category, and four were reviewed for MMO at baseline. Four articles assessed pain perception, and two assessed MMO at 1 month. Five articles were analyzed upon comparing pain perception at baseline and 1-month follow-up. The mean difference was -2.54 [95% CI: -3.38; to -1.70] in the intervention group and -2.33 [95% CI: -4.06; to -0.61] in the control group. Two articles were analyzed upon comparing MMO at baseline and 1-month follow-up. The mean difference in the intervention group was 3.69 [95% CI: -0.34; 7.72], whereas that in the control group was 3.62 [95% CI: -3.43; 10.67].Conclusions Both therapies can be used in the management of myogenic TMD. Due to the marginal differences between the baseline and 1-month values, our results could not confirm the efficacy of combination therapy.

Chewing performance of patients with worn dentition before and after restorations: A scoping review

BACKGROUND

Tooth wear is a multifactorial complex process related to the loss of dental tissue, due to chemical or mechanical processes, by abrasion, attrition, erosion. Restorative treatment represents an attempt to rebuild and recreate the lost structure.

OBJECTIVE

This scoping review aims to investigate whether restorative treatment of worn dentition (either with direct or indirect adhesive composite adhesive procedures or with prosthetic techniques) can have an impact on the masticatory performance parameters.

METHODS

A scoping review was conducted on multiple databases (Pubmed, Medline CENTRAL, ICTRP), following the PRISMA guidelines. Abstracts of research papers were screened for suitability, and full-text articles were obtained for those who satisfied the inclusion and exclusion criteria.

RESULTS

Only one article meet the inclusion criteria of the review. Restorative treatment of worn dentition although have a positive impact on the self-report ability to chew, has no effect on the masticatory performance test.

CONCLUSION

At the moment, not enough evidence to comment on the actual therapeutic role of restorative treatment on tooth wear is available. Clinicians, before taking any clinical decision, should carefully discuss with patients the needs and expectations of the treatment plan.

Acute dental malocclusion associated with lateral pterygoid muscle partial tear: Case Report and literature review

BACKGROUND

The article presents a rare case of acute malocclusion produced by a unilateral partial tear of the lateral pterygoid muscle and an up-to-date literature review of the pathology.

CLINICAL PRESENTATION

A 37-year-old female was examined; her chief complaints were pain on the right side of the temporomandibular joint (TMJ) area and mastication impairment associated with major occlusal modifications and anterior open bite. After magnetic resonance imaging (MRI) and cone beam computed tomography (CBCT) of the TMJ and subsequent MRI for soft tissue, the final diagnosis was a partial right lateral pterygoid muscle tear.

CONCLUSION

The case shows the value of combined imaging in temporomandibular disorders (TMD) and the importance of soft tissue evaluation in addition to articular examination, as the primary pathology might lie outside the joint. The authors' review of the current literature did not hitherto reveal a similar case.

Advancing Universal Oral Health Coverage via Person-Centred Outcomes

The World Health Organization member states proposed a comprehensive "Global Strategy on Oral Health," which includes achieving universal oral health coverage by 2030. Challenges and barriers, including persistent inequalities, will hamper the achievement of universal oral health coverage. In low- and middle-income countries, the oral health of a large proportion of the population has been neglected, increasing oral health inequalities. In high-income countries, some receive excessive dental treatment, whilst particularly those with higher needs receive too little dental care. Therefore, an analysis of individual countries' needs, encompassing the training of oral health professionals in a new philosophy of care and attention and the optimisation of the existing resources, is necessary. Distancing from a person-centred focus has prompted individual and societal issues, including under-/overdiagnosis and under-/overtreatment. The person-centred approach considers the perceptions, needs, preferences, and circumstances of individuals and populations. Patient-reported outcome measures, such as self-rated and -reported health, reflect an individual's overall perception of health and are designed to mediate human biology (ie, the disease) and psychology. The usage of patient-reported outcome measures in dentistry to place the individual at the centre of treatment is delayed compared to other areas. This paper discusses some challenges and potential solutions of patient-reported outcome measures in dentistry for achieving universal oral health coverage.

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'.

Photobiomodulation Therapy on the Palliative Care of Temporomandibular Disorder and Orofacial/Cervical Skull Pain: Preliminary Results from a Randomized Controlled Clinical Trial

The main symptoms of temporomandibular disorders (TMDs) are pain from musculoskeletal and/or joint-in the head and neck region-and complaints of difficulty in mandibular movements. The photobiomodulation therapy (PBMT) has been reported as a promising treatment in the management of these symptoms. The objective of this research was to assess the effect of PBMT immediately after irradiation on TMDs symptoms under a prospective clinical trial, randomized, triple-blinded, placebo-controlled, and with two parallel arms. According to the RDC/TMD, maximum mouth opening (MMO) and pain in the orofacial/cervical muscles and temporomandibular joint (TMJ) were recorded. One hundred forty-five participants (71 placebo and 74 PBMT experimental) were analyzed after irradiation protocols (sham-PBMT or PBMT) at the orofacial/cervical skull musculature and at the TMJ. The results showed a reduction in the total pain score (p = 0.026), a reduction in the number of painful points (p = 0.013), and an increase in the MMO (p = 0.016) in the PBMT protocol group when compared to the placebo protocol (sham-PBMT). The PBMT was shown to be effective in reducing orofacial/cervical skull pain immediately after the irradiation. It is clinically relevant and should be taken into consideration by professionals who are dedicated to treating this pathology because, in addition to bringing comfort to patients who need dental treatment, it also consists of a low-cost and low technical complexity clinical approach.

Evaluation and management of temporomandibular disorders. Part 2: an orthopaedic physical therapy update on examination and clinical reasoning

Temporomandibular (TM) disorders afflict many people globally and, despite the presence of existing peer-reviewed material that assists conservative orthopedic providers, recent advances in knowledge indicate that updated resources are required for students, clinicians, and educators. This two-part series builds off previously published material to present newer supplementary information that can be useful during the evaluation and management processes. Content in Part 1 of this series includes a discussion about the factors that have been shown to contribute to TM disorders, an updated perspective of relevant pain science, a discussion of self-report outcome measures, and various different topics related to the examination of patients with TM disorders. Part 2 addresses information related to the temporomandibular joint disc, joint hypermobility, oral splints, and clinical reasoning. In combination with other available publications, this two-part series provides clinicians an opportunity to improve their delivery of effective and efficient clinical services for people diagnosed with TM disorders.

Oral splints in the management of nociceptive pain and migraines: A scoping review

Temporomandibular disorders (TMDs) are characterized by numerous pain manifestations. Their treatment often involves the use of an oral splint. Recent research has found a relationship between migraines, nociceptive pain and TMDs. The aim of the present study was to perform a scoping review of studies in order to evaluate the effectiveness of the various types of oral splint in the treatment of migraine or nociceptive pain. Publications were retrieved from seven databases (PubMed, Web of Science, EMBASE, Scopus, ProQuest, SpringerLink and Ovid). Out of the 15 included publications, three studies were before and after studies, with no control group, whereas the other twelve studies were clinical trials, among which two publications were crossover studies. A clear, single distinction of pain was difficult to describe. Therefore, numerous publications focused on a combination of various types of pains, including myofascial, temporomandibular joint, headaches and migraine-like symptoms, all of which mimicked TMD pain. Overall, six studies used the stabilization splint (SS), three explored the comparison between the SS and the nociceptive trigeminal inhibition splint (NTIS) and two the NTIS. The majority of publications reported a positive outcome of splint therapy. Regarding the type of oral splint usage, the most commonly used one was the SS, followed by the NTIS. The definition and assessment of pain were heterogenous in the identified articles. The findings of the current study showed that occlusal splints may help with pain management, and that effective treatment of TMD-related pain at an early stage can enhance the quality of life of patients.

Are acupuncture and dry needling effective in the management of masticatory muscle pain: A network meta‐analysis of randomised clinical trials

BACKGROUND

Several studies have shown that both acupuncture and dry needling are effective in the treatment of musculoskeletal pains. Therefore, the aim of this network meta-analysis (NMA) was to investigate the treatment outcome of acupuncture and dry-needling for masticatory muscle pain (TMD-M) and to compare with active and inactive placebo.

MATERIAL AND METHOD

An electronic search was performed to identify randomised controlled trials (RCTs) published until September 2019, comparing dry-needling, acupuncture, and inactive as well as active placebo in patients with TMD-M. Outcome variables were post-treatment pain intensity, pressure pain threshold (PPT), and maximum mouth opening (MMO). The quality of evidence was rated according to Cochrane's tool for assessing the risk of bias. Mean difference was used to analyse via frequentist NMA using STATA-software.

RESULTS

Both NMA and direct pairwise meta-analysis have shown that there was no difference between active treatment with either acupuncture or dry-needling when compared to active and inactive placebo in patients with TMD-M with respect to pain intensity, and PPT (p > .05). However, there was a significant increase in MMO following dry-needling when compared to the placebo (very low-quality evidence).

CONCLUSION

Despite the short-term positive effect of MMO by dry-needling, this NMA could not show any pain-reducing effect in patients with TMD-M by acupuncture or dry-needling when compared to an active or inactive placebo. Taken together, this NMA indicates that it is the placebo effect that accounts for the majority of the treatment effect of TMD-M, rather than a real therapeutic effect of acupuncture/dry-needling.

The Impact of Wearing a Face Mask during the COVID-19 Pandemic on Temporomandibular Joint: A Radiological and Questionnaire Assessment

Aim  Several health problems have been reported to be triggered or facilitated by prolonged mask usage during the coronavirus disease 2019 (COVID-19) pandemic. While wearing a face mask, people tend to push their jaws forward and downward in a repetitive manner to hold their masks in the right position; these jaw motions may induce temporomandibular joint disorder (TMD). In this study, we aimed to investigate these repetitive jaw movements while wearing face masks and their effects on TMD.

Patients and Methods  Patients who applied with TMD signs between June 2020 and May 2021 were evaluated prospectively. A survey using a questionnaire was conducted to define patients with TMD that caused only by mask-related repetitive jaw movements. Demographic data (age and gender), mean duration of daily mask usage, mask type, and magnetic resonance imaging results were recorded.

Results  Prolonged daily mask usage (≥8 hours/day) was significantly higher in patients with mask-related habits (group a) with a rate of 40.4% ( p ≈ 0.001). Also, in this group, the disc displacement with reduction rate (54.6%) was higher compared with other groups ( p ≈ 0.010). On the contrary, patients with no underlying risk factor (group c) showed an unexpected high osteoarthritis rate ( p ≈ 0.029).

Conclusions  In this study, we demonstrate that correcting the position of a face mask by repetitive jaw movements can increase the occurrence of TMD. Informing individuals wearing face masks about the risk of TMD and the importance of choosing the appropriate mask size according to the face shape are important issues to be addressed in the near future.

Patients' perceptions on temporomandibular disorder treatment with hydrostatic oral splints - a pilot study

Objective

To evaluate temporomandibular disorder (TMD) treatment with a prefabricated, hydrostatic oral splint (HOS) based on self-reported patient’s symptoms using a standardized questionnaire.

Methods

Two hundred fifty-eight questionnaires from patients diagnosed with TMD and subsequently treated with HOS were collected from two independent private practices. Based on patient’s comfort the questionnaire recorded TMD symptoms and symptom regression. Descriptive and comparative statistics was carried out using SPSS.

Results

A total of 221 questionnaires were analyzed. Patients reported TMD symptoms such as pain (93.2%), TMJ clicking (66.1%), headache (25.8%), cervical spine disorders (23.5%), restricted mouth opening (22.6%) and tinnitus (11.8%). For most symptoms, improvement was reported mostly after two weeks, except for tinnitus, where positive effects were usually reported after four weeks.

Conclusion

HOS seem to be effective for immediate treatment of pain and other TMD symptoms. Based on the available data, a treatment period of four weeks can be recommended.

Temporomandibular joint trauma and disability assessment - A longitudinal exploratory study

BACKGROUND

Orofacial trauma can encompass, isolated or not, several anatomical regions, namely facial, dental and temporomandibular joint (TMJ), one of the most complex joints in the human body. Evidence-based knowledge in the field of TMJ trauma and in temporomandibular joint disorders (TMD) diagnosis and treatment, provides the necessary data for medico-legal assessment.

OBJECTIVE

The aim of this study is to bring up epidemiological data referring to TMJ injuries and sequelae, in order to present a medico-legal approach of TMJ disability.

METHODS

An observational longitudinal exploratory study was performed in the database of the National Institute of Legal Medicine and Forensic Sciences, Portugal, between 2000 and 2017, regarding inclusion and exclusion criteria.Statistical significance was set as P‹0.05, Fisher's exact test, Binomial test and Goodman and Kruskal's test were used.

RESULTS

Post-traumatic orofacial reports (n = 2622) included 234 TMJ-injury and 149 TMJ-sequelae.Epidemiological data was presented regarding age,gender, professional status and etiology. There was a statistically significant association between TMJ injury and TMJ sequela, despite a weak relation (ƛ = 0.170). No statistically significant association was identified between TMJ-injury/TMJ-sequelae and the professional status, etiology.

CONCLUSION

The TMJ sequela group is smaller than the TMJ-injury, reflecting that 2/3 of the injuries have been cured without a monetary compensation value and without Health costs. The association between TMJ injury and TMJ sequelae reinforces the necessity of preventive measures in TMJ trauma, namely in physical violence context and in medico-legal impairment.

Association between temporomandibular disorders with clinical and sociodemographic features: An observational study

BACKGROUND

Temporomandibular disorders (TMD) are the most common orofacial impairment, but the relevance of certain clinical features in TMD is not clear.

OBJECTIVE

The main objective of this study was to analyse if temporomandibular disorders (TMD) are associated with sociodemographic (eg age, height, weight, body mass index and gender), psychological (eg anxiety and depression) and clinical features (eg use of dental splints, orthodontics, retainers, bruxism, sleep disturbance, familiar prior history of TMD and dental occlusion).

METHODS

An observational study was conducted to calculate the correlation of TMD, as assessed with DC/TMD criteria, with sociodemographic, psychological and clinical features on 59 voluntary subjects with TMD (n = 45) and without TMD (n = 14). Sex, height, weight, body mass index, age, use of dental splint, orthodontics, retainers, parafunctional disorders, sleep disturbance, familiar history of TMD, bruxism, anxiety, stress and dental occlusion class data were included in a multivariable correlation analysis to determine which variables are associated with TMD and bruxism.

RESULTS

TMD was found to be correlated with none of the features assessed (P > .05), but a negative correlation with the use of dental splint (P < .05). Dental occlusion class showed no statistically significant correlation with any assessed feature (P > .05).

CONCLUSION

The etiology of TMD is not clear and considering certain clinical features including dental occlusion are not justified in the evidence-based TMD practice for making irreversible occlusal treatment decisions.

Diagnostic accuracy of the short-form Fonseca Anamnestic Index in relation to the Diagnostic Criteria for Temporomandibular Disorders

STATEMENT OF PROBLEM

Screening for temporomandibular disorders (TMDs) is important in research and clinical practice. The short-form Fonseca Anamnestic Index (SFAI) was recently introduced but had only been validated for muscle disorders.

PURPOSE

The purpose of this clinical study was to determine the diagnostic accuracy of the SFAI and its discrete and pooled items in relation to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) benchmark.

MATERIAL AND METHODS

A total of 866 consecutive participants with TMDs and 57 TMD-free controls (aged ≥18 years) were recruited. The participants (n=923; mean age 32.8 ±13.3 years; women 79.2%) answered the FAI, and TMD diagnoses were derived based on the DC/TMD protocol and algorithms. The 5-item SFAI, which comprised 2 pain-related and 3 function-related TMD questions, was subsequently acquired and assessed with reference to the DC/TMD diagnoses. The receiver operating characteristics (ROC) was used to verify accuracy (area under the curve [AUC]) and the best cutoff points. Sensitivity, specificity, predictive values, and likelihood ratios were also examined.

RESULTS

Pain-related (PT) and intra-articular (IT) TMDs were present in 48.3% (446/923) and 82.7% (763/923) of the participants, respectively. The SFAI demonstrated high accuracy for identifying all TMDs, PT, and IT (AUC of 0.97, 0.99, and 0.97, respectively). The best cutoff points were 12.5 for all TMDs/IT and 17.5 for PT. Sensitivity of the SFAI ranged from 90.7% to 97.5% while specificity varied from 93.0% to 96.5%, with the highest values for PT. As positive predictive values (99.4% to 99.5%) were greater than negative ones (41.7% to 83.3%), the SFAI was better at detecting the presence than the absence of TMDs. With reference to PT, the sensitivity, and specificity of the 2 discrete and pooled pain-related questions (questions 3 and 4), extended from 82.3% to 99.3% and 77.2% to 96.5% respectively. With regard to IT diagnoses, sensitivity and specificity ranged from 56.0% to 98.3% and 86.0% to 98.3% for the 3 discrete and pooled function-related items (questions 1, 2, and 5).

CONCLUSIONS

The SFAI presented high degrees of diagnostic accuracy in relation to the DC/TMD and can be used for screening TMDs. SFAI scores between 15 and 50 points should be used to identify the presence of TMDs, with scores ≥20 points specifying possible pain-related TMDs.

Patient Safety in Dental Practice: Lessons to Learn About the Risks and Limits of Professional Liability

Introduction

Health professionals should work with the notion of risk involved in the health care process. Dental practice risk is of particular interest because it encompasses both aesthetic and functional components. Focusing on guidelines suggested by the World Health Organization and objectives on patient safety, this study has 2 objectives: to present Portuguese medicolegal data on corporal damage evaluation related to iatrogenic sequelae during dental practice and to present updated evidence on patient safety.

Materials and methods

A retrospective study was performed by analysing data from the database of the Laboratory of Forensic Dentistry of the Faculty of Medicine, University of Coimbra, Portugal, from 2013 to 2018.

Results

One hundred seven medicolegal files were selected according to the inclusion and exclusion criteria. Iatrogenic sequelae (73.8%, 79 out of 107) were categorised as risks (60 out of 79) and malpractice (19 out of 79). The risk was associated mostly with mandibular dysfunction and orthodontic treatment (62.2%). Malpractice was mostly associated with neurological deficit and implant rehabilitation (47.4%).

Discussion and conclusion

Greater attention to these data by professionals was emphasised, especially when considering patient safety and health care quality. This article presents the Portuguese data on professional liability in the field of dental practice, categorising iatrogenic sequelae into risks and malpractice, as well as the oral rehabilitation procedure and timeline.

Three-dimensional finite element analysis of temporomandibular joints in patients with jaw deformity during unilateral molar clenching before and after orthognathic surgery

To analyze the effects of orthognathic surgery on stress distributions in the temporomandibular joint (TMJ) of patients with jaw deformity during unilateral molar clenching (UMC) by using three-dimensional (3D) finite element method.Nine patients with jaw deformity (preoperative group, 26.1 ± 5.6 years old) and 9 asymptomatic subjects (control group, 22.0 ± 6.0 years old) were selected. Furthermore, the patients with jaw deformity were also considered as the postoperative group after undergoing orthognathic surgery. Finite element models for the mandible, articular disc, and maxilla were developed through cone beam computed tomography. Contact was used to simulate the interaction of the articular disc, condyle, fossa, and upper and lower dentition. The muscle forces and boundary conditions corresponding to the UMC were applied on the models.The stresses on both TMJs of the control group were significantly different, whereas there was no significant difference on both sides for the preoperative group. All the stresses of the preoperative group were greater than those of the control and postoperative groups, except the minimum principal stress on the ipsilateral fossa.Orthognathic surgery is beneficial for alleviating the abnormal stress distributions on TMJ.

The Arabic Fonseca Anamnestic Index: Psychometric properties and use for screening temporomandibular disorders in prospective orthodontic patients

OBJECTIVE

This study aimed to develop/evaluate the psychometric properties of the Arabic Fonseca Anamnestic Index (FAI-A) and estimate the prevalence of TMDs in prospective orthodontic patients.

METHODS

The FAI-A was derived by forward-backward translation/cross-cultural adaption of the English FAI. Psychometric assessment of the FAI-A was performed with 308 orthodontic patients. Reliability was established via internal consistency and test-retest techniques, whereas, validity was verified by construct and convergent validity.

RESULTS

Cronbach's alpha value for the FAI-A was 0.77, and the intraclass correlation coefficient was 0.99. For construct validity, the distribution of eigenvalues indicated that three items (mouth opening difficulty, jaw movement difficulty, and jaw fatigue) accounted for 60.5% of the total variance observed. For convergent validity, the FAI-A items were significantly correlated to the global question.

CONCLUSION

The FAI-A showed good reliability/validity and may be useful for screening TMDs. About 17% of prospective orthodontic patients presented with moderate-to-severe TMD symptoms.

Evaluation of the Stomatognathic System before and after Osteopathic Manipulative Treatment in 120 Healthy People by Using Surface Electromyography

Objective: To investigate the action of osteopathic manipulative treatment on the muscular activity of the stomatognathic apparatus by using surface electromyography (sEMG). Material and Methods: Surface electromyography (sEMG) was performed on the masseter and anterior temporalis muscles of 120 subjects (73 F; 47 M), both at time T0 and T2. The sample was divided into three randomized groups of 40 subjects each: control, placebo, and osteopathic manipulative treatment (OMT). In the T1 interval between the two evaluations, the control group was not treated, the placebo group underwent a placebo treatment, and the OMT group underwent manipulative treatment. The mean value of each measurement and its coefficient of variation, between time T0 and T2, were calculated for both the intragroup (OMT, placebo, control) and the intergroup (OMT-placebo, OMT-control). Outcomes: In 40% of the subjects, statistically significant improvements were highlighted in the OMT. Whereas, the statistically significant results of the placebo and control groups were 7.5% and 17.5%, respectively, of which more than 75% moved away from the physiological range, showing a worsening of the muscular activity. This analysis showed statistically significant variations (p ≤ 0.05) in the OMT group compared to the placebo and the control groups. Conclusions: OMT determines variations of the activity of masticatory muscles.

Effects of Rapid Palatal Expansion on Chewing Biomechanics in Children with Malocclusion: A Surface Electromyography Study

Malocclusion during childhood may affect both morphology and masticatory function and could greatly affect the subsequent growth and development of the jaws and face. The purpose of this study was to evaluate the efficiency of surface electromyography in describing the effects of the rapid palatal expansion (RPE) on Masseter (M) and Temporalis Anterior (T) muscles' activity in 53 children with different types of malocclusion: bilateral posterior crossbite (BPcb), underdeveloped maxillary complex without crossbite (NOcb) and unilateral posterior crossbite on the right (UPCBr) and on the left (UPCBl). The muscular activities during chewing tasks were assessed bilaterally before and after RPE application and three months after removal. Both the envelope's peak (µV) and its occurrence (% of chewing task) were extracted from the surface electromyography signal. Our results showed the presence of statistically significant differences (p < 0.05) on temporomandibular joint muscles, across different assessments, in all the tested populations of subjects. Surface electromyography demonstrated a relationship between the correction of a maxillary transverse discrepancy and the restoration of a muscle's activation patterns comparable to healthy subjects for both T and M.

Occlusion and Temporomandibular Disorders: A Long-Standing Controversy in Dentistry

The relationship between temporomandibular disorders (TMDs) and occlusion remains controversial. Some authors believe that occlusion is the primary factor in the onset of TMD symptoms, whereas others feel that occlusion has no role in this at all. The majority of reasoning behind causation is based upon anecdotal rather than scientific evidence. Existing evidence in the literature supports the absence of a disease-specific association. This article describes this controversy and provides the reader with findings from contemporary literature.

Effects of estradiol hormone in menopausal women on anterior disc displacement of temporomandibular joint

Anterior disc displacement is a condition when the articular disc is in the anterior normal position. Epidemiological research shows that the prevalence of TMD is higher in women than in men. Women have a dominant hormone that is not owned by men, the hormone estradiol. Estrogen receptors and the hormone progesterone are found in articular joints in humans. Joint structure, extracellular matrix remodeling, and bone volume modification can be affected by sexual hormones. It was thought to cause changes in connective tissue in the TMJ structure. This study aims to determine the effect of the level of the hormone estradiol in menopausal women on anterior temporal disc displacement of the temporomandibular joint. Subjects were 40 postmenopausal women who were examined for temporomandary joints. The diagnosis of anterior disc displacement was made using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC / TMD) method. Subjects were grouped into subjects with normal tempromandibular joints and subjects with anterior disc displacement. Estradiol hormone was examined by the immunoassay method. This study’s conclusion is estradiol hormone in menopausal women with anterior disc displacement is higher than menopausal women without anterior disc displacement.

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.

Anterior open bite due to idiopathic condylar resorption during orthodontic retention of a Class II Division 1 malocclusion

A common dilemma when treating anterior open bite is understanding its etiology. Idiopathic condylar resorption (ICR) can cause open bite in affected individuals. Although it is prudent to not treat patients with ICR until active resorption has ceased, orthodontists may begin treating them because anterior open bite from ICR may not appear before or during their orthodontic treatment. This article reports a 12-year-old female who was diagnosed with ICR 10 months after completion of her orthodontic treatment for a Class II Division 1 malocclusion. When a young patient with a high mandibular angle and previous skeletal or dental Class II malocclusion returns with an open bite during the retention phase, the patient's condyles must be carefully examined to determine whether any temporomandibular joint disorder, such as ICR, is present. Currently, the controversy over the cause and the cure for ICR is continuing to challenge orthodontists in diagnoses and treatments. Orthodontists should closely monitor and offer informed treatment options to patients with risk factors for ICR or signs of its pathology that might develop at any stage of orthodontic treatment, including the retention period.

Potential Role of Rebamipide in Osteoclast Differentiation and Mandibular Condylar Cartilage Homeostasis

Background:

Temporomandibular joint osteoarthritis (TMJ-OA) is a degenerative disease that involves changes in subchondral bone and progressive degradation of cartilage. Currently, rebamipide, a gastroprotective drug, is administered to protect gastric mucosa and accelerate ulcer healing.

Objectives:

Recent studies have shown that rebamipide also attenuates cartilage degeneration by suppressing oxidative damage and inducing homeostasis of the extracellular matrix of articular chondrocytes. Regarding the latter, reduced expression of cathepsin K, NFATc1, c-Src, and integrin β3, and increased expression of nuclear factor-kappa B, have been found to be mediated by the transcription factor, receptor activator of nuclear factor kappa-B ligand (RANKL).

Methods:

Treatment with rebamipide was also found to activate, mitogen-activated protein kinases such as p38, ERK, and JNK to reduce osteoclast differentiation. Taken together, these results strongly indicate that rebamipide mediates inhibitory effects on cartilage degradation and osteoclastogenesis in TMJ-OA.

Results and Conclusion:

Here, we highlight recent evidence regarding the potential for rebamipide to affect osteoclast differentiation and TMJ-OA pathogenesis. We also discuss the potential role of rebamipide to serve as a new strategy for the treatment of TMJ-OA.

Assessment of the Orofacial Pain Patient

The diagnostic process of pain in the oral, facial, and head region is often perceived as more difficult due the numerous, extensively innervated structures located in this area. To successfully manage the patient with these pain presentations, it is critical for the clinician to spend ample time procuring a good medical and dental history. A systematic approach to the physical examination will ensure that sufficient data are acquired without overlooking potentially important contributing factors. The use of adjunctive laboratory tests and imaging studies should be based on the findings in the history and examination.

The mechanics of dental occlusion and disclusion

BACKGROUND

The mechanical environment associated with occluding teeth is the foundation for a wide range of research topics, clinical practice and dogma, product development and marketing, and medico-legal issues. The purpose of this study was to experimentally examine the relationships between occlusal factors and their impact on the associated contact forces.

METHODS

Matching pairs of 0°, 20°, 33° and 40° cusp first molar denture teeth were placed into Class I, II and III molar relationships. As the teeth were brought together into occlusion and then separated, the loads experienced by the mandibular tooth were continuously measured by a load cell that was supporting it.

FINDINGS

Loess smoothing splines were fitted to all data curves to calculate 95% confidence intervals. All lateral force magnitudes and directions were statistically different when compared between classes of occlusion, cusp angles, and occlusion vs. disclusion. Noteworthy counterintuitive observations were that the lateral contact force components were generally higher during disclusion than occlusion, the peak lateral force magnitudes did not always occur when the occlusal force was maximum, and the lateral contact force component magnitude can be larger than the occlusal force.

INTERPRETATION

Wedging and friction account for these unexpected results. The data indicate that each occlusion/disclusion cycle is characterized by complex transient loads that may impact wear facet and non-carious cervical lesion formation, implant and restorative failures, various aspects of occlusal trauma, and the concept of axial occlusal loading.

Potential risks of orthodontic therapy: a critical review and conceptual framework

This review examines some of the potential risks of orthodontic therapy along with their evidence base. The risks of orthodontic treatment include periodontal damage, pain, root resorption, tooth devitalization, temporomandibular disorder, caries, speech problems and enamel damage. These risks can be understood to arise from a synergy between treatment and patient factors. In general terms, treatment factors that can influence risk include appliance type, force vectors and duration of treatment whilst relevant patient factors are both biological and behavioural. Hence, the natural variation between orthodontic treatment plans and patients gives rise to variations in risk. A good understanding of these risks is required for clinicians to obtain informed consent before starting treatment as well as to reduce the potential for harm during treatment. After considering each of these risks, a conceptual framework is presented to help clinicians better understand how orthodontic risks arise and may therefore be mitigated.

Dental Angle class asymmetry and temporomandibular disorders

OBJECTIVES

The aim of this study was to determine whether there is an association between the presence of asymmetric molar or canine Angle classes on the two sides and the presence of temporomandibular joint dysfunction (TMD).

MATERIALS AND METHODS

Participants to the study were divided into two groups: TMD group (90 patients) or a control group (58 patients). In the TMD group, clinical assessment for TMD was performed according to the Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) guidelines by the same two trained examiners. In both groups, all subjects underwent an assessment of dental occlusion, focusing on the assessment of bilateral canine and molar Angle class relationship. The study protocol was reviewed and approved by the Institutional Review Board of the University of Padova, and each participant gave written consent to take part in the investigation.

RESULTS

TMJ pain was diagnosed in 58, disk displacement in 96, arthrosis in 17, and muscle pain in 46 individuals. Molar Angle class was symmetrical in 86 individuals and asymmetrical in 62 subjects. Molar Angle class was not correlated with any of the TMD diagnoses. Canine Angle class was correlated with TMJ arthrosis. Correlation values with the other TMD diagnoses were low and were not significant.

CONCLUSIONS

It can be suggested that an association between dental Angle class asymmetry and TMDs does not exist and that the role of dental asymmetries as a factor correlated with the presence of TMD signs and symptoms is minimal.

Orthodontics is temporomandibular disorder-neutral

OBJECTIVES

To assess if subjects with a clinical diagnosis of temporomandibular disorders (TMDs) have a similar prevalence of orthodontic history as a population of TMD-free individuals and to assess if those subjects who have a history of ideal orthodontics have fewer symptoms than those with a history of nonideal orthodontics.

MATERIALS AND METHODS

Two groups of age- and sex-matched individuals belonging to either a study ("TMD") or a control group were recruited. Subjects who underwent orthodontic treatment were classified as having a history of ideal or nonideal orthodontics based on the current presence of normal values in five reference occlusal features.

RESULTS

The correlation with a history of orthodontic treatment was not clinically significant for any of the TMD diagnoses (ie, muscle pain, joint pain, disc displacement, arthrosis), with Phi (Φ) coefficient values within the -0.120 to 0.058 range. Within the subset of patients with a history of orthodontics, the correlation of ideal or nonideal orthodontic treatment with TMD diagnoses was, in general, not clinically relevant or was weakly relevant.

CONCLUSIONS

Findings confirmed the substantial absence of clinically significant effects of orthodontics as far as TMD is concerned. The very low correlation values of a negative or positive history of ideal or nonideal orthodontics with the different TMD diagnoses suggest that orthodontic treatment could not have a true role for TMD.

Prevalence and associated factors for temporomandibular disorders in Chinese civilian pilots

PURPOSE

Piloting is a special profession with prolonged stress, which could induce the occurrence of TMD. This sample is useful to reduce the effect of confounders in the analyses. Based on this, the present study aims to determine the prevalence and associated factors for TMD in civilian pilots of China.

METHODS

A cross-sectional epidemiological survey was carried out in 616 male subjects (aged 23-52 years). The questionnaire included general information, chewing preference (bilateral or unilateral), and Trait Anxiety section of Spielberger State-Trait Anxiety Inventory (STAI-T). The clinical examination contained TMD screening per research diagnostic criteria for TMD and diagnosis of sleep bruxism per American Academy of Sleep Medicine standards. The level of statistical significance was set at P ≤ 0.05.

RESULTS

The program was conducted from June 2012 to April 2013, in which period, and the percentage of TMD in the samples we examined was 33.3 % (=205/616). Only high anxiety (OR 2.48; 95 % CI 1.25-4.90) and unilateral chewing preference (OR 12.67; 95 % CI 7.77-20.65) were the most significant associated factors with TMD. Also, salivary cortisol and the STAI-T score had a significant correlation (r = 0.47, P < 0.001).

CONCLUSIONS

It was more reliable to study the associated factors on TMD with the exclusion of the possible confounding factors, and only unilateral chewing preference and psychological stress had a significant association with TMD. In addition, the salivary cortisol levels might assist to assess psychological stress in epidemiological research.

The prevalence of temporomandibular disorders in patients with late whiplash syndrome who experience orofacial pain: a case-control series study

BACKGROUND

The authors conducted a study to compare the frequency of specific temporomandibular disorder (TMD) diagnoses in patients who had late whiplash syndrome (LWS) with that in a control group.

METHODS

The authors recruited 65 patients who had orofacial pain and a previous diagnosis of LWS and 65 age- and sex-matched control patients who had chronic orofacial pain without a history of whiplash injury (WI) for a case-control series study. All patients completed a questionnaire pertaining to the Research Diagnostic Criteria for Temporomandibular Disorders and underwent a clinical examination.

RESULTS

The authors compared the frequency of TMD diagnoses in case patients with that in control patients by using a χ(2) test; they set the α level a priori at .05. The number of patients diagnosed with myofascial pain (MP) and disk displacement with reduction (DDWR) was significantly higher in the case group than in the control group (P = .002 and P = .001, respectively).

CONCLUSIONS

The results of this study show a higher frequency of MP and DDWR in patients with LWS than in patients with chronic orofacial pain and no history of WI. Practical Implications. Clinicians should be knowledgeable about the correlation between WI and TMD so they can inform and treat patients accurately.

[Does dental class II division 2 predispose to temporomandibular disorders?]

Because of its anatomical/physiological characteristics, the Class II division 2 (class II, div. 2) is one of the malocclusions considered as a possible risk factor for Temporomandibular disorders (TMD). A literature review was conducted from the electronic databases of Medline and Elsevier Masson, through the year 2010, in order to clarify the relationships that may exist between Class II division 2 and TMD. This research helped identify 50 articles: 7 articles specifically concerned the Class II div. 2, 37 articles concerned some of the characteristics of the Class II div. 2, considered individually (Class II, deep bite, retroclined maxillary incisors, mandibular retrognathism) and 6 articles orthodontic treatment. From the conclusions of these studies, the Class II, div. 2 does not appear to represent a significant risk factor for TMD. The clearest association would involve mandibular retrognathism and the risk of articular disk displacement. However, given the low number of articles published on this topic, the methodological variability and the contradictory results, it is difficult to identify reliable conclusions and, consequently, the therapeutic indications for the treatment of Class II div. 2 patients with TMD.

Digital Evaluation of Functional Occlusion Parameters and their Association with Temporomandibular Disorders

CONTEXT

Dental researchers are contradictory in their opinion on the role of occlusion in TMD. Occlusal evaluation of both conventional and digital methods in TMD patients will provide the accurate information about the factors accountable for occlusal instability. Identifying the factors responsible will facilitate precise diagnosis and treatment for TMD.

AIM

The AIM of the study was to determine the dynamic occlusal parameters strongly associated with the etiology of Temporomandibular disorders.

MATERIAL AND METHODS

Study group consisted of 100 patients; it included 50 patients with normal TMJ(Group I) and remaining 50 patients had a minimum of one positive sign or symptom of Temporomandibular disorder (GroupII). The patient's dynamic occlusal contacts were evaluated by both conventional and digital methods. The Articulating paper was utilized for conventional occlusion analysis. During conventional analysis centric, lateral and protrusive interferences were evaluated along with loss of vertical dimension. Digital occlusal analysis was performed with T-Scan III. Clusion time, disclusion times were recorded for both groups. Chi-square and Student't' statistical analyses were performed to ascertain the association and statistically significant difference between the groups using SPSS19.

RESULTS

Group II patients predominantly (66%)had Group-function occlusion compared to Group I subject. Centric slide more than 2 mm found to have strong influence (p value 0.008) on the etiology of TMD. Among the occlusal interferences evaluated balanced side interferences had a strong correlation with TMD with p-value of 0.003. Working side interferences, protrusive interferences had a p-value of 0.157, 0.826 respectively, indicating weak association. T-Scan analysis showed Group I had 0.689, 0.9136, 0.7952, 0.9794 seconds of clusion, left, right, protrusive disclusion time respectively compared to corresponding 1.862, 1.7995, 1.6978, 1.9296 seconds for Group II. Statistically significant difference (p≤0.05) was found between the mean values of both groups.

CONCLUSION

Among the dynamic occlusal parameters evaluated centric slide and balancing side interferences were found to be highly influential in TMD etiology. TMD patients had prolonged clusion and disclusion times compared to healthy TMJ patients.

A cross-sectional study of the relationship between serum sexual hormone levels and internal derangement of temporomandibular joint

Temporomandibular disorders (TMD) are defined as clinical conditions that involve the masticatory muscles, temporomandibular joint (TMJ) or both. The aim of this study was to evaluate serum 17β-oestradiol and progesterone levels in menstruating women affected by internal derangement of the TMJ. A total of 142 women (mean age 30·2 ± 6·7) who referred to medical diagnostic laboratory of Iranian Academic Centre for Education, Culture and Research (ACECR), Mashhad Branch, were enrolled during 2007 and 2008. Forty-seven individuals had disc displacement with reduction (Group IIa) according to Research Diagnostic Criteria (RDC)/TMD Axis I diagnosis. Radioimmunoassay was used for the detection of serum 17β-oestradiol and progesterone levels in all 142 subjects. The mean progesterone level was significantly higher in control group (11·6 ± 10·4 ng mL(-1) ) compared to women with TMD (8·4 ± 6·8 ng mL(-1) , P = 0·03). No significant difference was found in two groups regarding 17β-oestradiol level. Lower progesterone level in women with TMD can suggest the more important role of this hormone in the development of the disorder.