Gender Difference in Associations between Chronic Temporomandibular Disorders and General Quality of Life in Koreans: A Cross-Sectional Study

Cross-Cultural Validation of the Thai Oral Health Impact Profile for Temporomandibular Disorders

OBJECTIVES

The Oral Health Impact Profile for Temporomandibular Disorders (OHIP-TMDs) is a validated condition-specific outcome measure to help guide decision-making in the management of the condition. There is no Thai version of OHIP-TMDs, and therefore the original English version needs cross-cultural adaptation translation, and validation with a Thai population to reduce the anomalies due to language and cultural differences. This study aimed to develop the Thai-language version of OHIP-TMDs, perform a cross-cultural adaptation to Thailand, and assess its content validity, internal consistency, reliability, and construct validity.

METHODS

The original English version of OHIP-TMDs was forward and backward translated into Thai language using the International Network for Orofacial Pain and Related Disorders methodology (INfORM) protocol for cross-cultural adaptation. The Content Validity Index (CVI) was performed by 5 orofacial pain (OFP) specialists to establish content validity. The OHIP-TMDs-T was then tested in 2 groups of Thai dental patients including 110 TMD patients and 110 control participants. The internal reliability and test-retest reliability (n = 30) were investigated in the TMD group using Cronbach alpha coefficient and intraclass correlation coefficient (2-way mixed effect model), respectively. The difference in OHIP-TMDs-T score between the TMD group and control group was investigated for known group validity.

RESULTS

Cronbach alpha and intraclass correlation coefficients were 0.942 and 0.797, respectively. The CVI collected from the OFP specialists was 0.92. There was a statistical difference in the OHIP-TMDs-T overall score between the TMD group (95% CI, 40-46) and control group (95% CI, 2.0-3.4) (Z = 9.060, r = 1, P < .001).

CONCLUSIONS

The OHIP-TMDs-T is a valid and reliable tool for evaluating the quality of life and the impact on oral health in Thai patients with TMD.

Muscle oxygenation and pain in different types of temporomandibular disorders

OBJECTIVES

Studies exploring variations in peripheral muscle oxygenation and pressure pain thresholds (PPT) of masticatory muscles in individuals with Temporomandibular Disorders (TMDs) are limited. The purpose of this study was to compare variations in peripheral oxygenation of the masseter muscle; PPT of the masseter and temporal muscles and correlate peripheral muscle oxygenation and PPT of the masseter muscle in individuals with different types of TMDs.

MATERIALS AND METHODS

Cross-sectional study involving 116 participants classified into three groups: muscle group (MG, n = 32), joint group (JG, n = 30) and muscle-joint group (MJG, n = 54). Individuals aged 26.97 ± 6.93, 68.97% female, 31,03% males were included. All participants were evaluated using the Diagnostic Criteria for Temporomandibular Disorders, Near-infrared spectroscopy (NIRS) for peripheral muscle oxygenation and pressure algometer for PPT.

RESULTS

There was no difference in masseter muscle oxygenation among groups. In the masseter muscle, a weakly positive correlation was observed between PPT and variation in tissue saturation index in the MG (rho = 0.365) and JG (rho = 0.317). In addition, the MJG expressed lower PPT (p = 0.004) than JG, demonstrating that MJG had more pain in this muscle.

CONCLUSIONS

MJG have lower PPT in the masseter muscle. Although the PPT is dependent on the type of TMDs, the correlation between PPT and oxygenation is weak. All TMDs groups evaluated (MG, JG, MJG) showed hemodynamic similarities of the masseter muscle.

CLINICAL RELEVANCE

Understanding pain thresholds and the hemodynamic behavior of the masticatory muscles contributes to a more assertive physiotherapeutic assessment in TMDs, serving as a basis for careful and individualized interventions.

Prevalence of temporomandibular disorders and their associated factors in Confucian heritage cultures: A systematic review and meta-analysis

BACKGROUND

Temporomandibular disorders (TMDs) may be an 'idiom' of psychological distress in Confucian heritage cultures (CHCs).

OBJECTIVES

This systematic review/meta-analysis estimated the prevalence of TMDs in CHCs and compared the differences in TMD occurrence between time periods and age groups. Additionally, the associated biopsychosocial risk factors were also examined.

METHODS

The study protocol was developed a priori following the PRISMA guidelines and Joanna Briggs Institute systematic review methodology (CRD42021245526). Electronic searches of seven databases were conducted from January 2002 to Dec 2021. Reference lists of identified studies were hand-searched for additional articles. Study selection, quality assessment, and data extraction were done. Meta-analysis was performed using the RevMan 5.4 software.

RESULTS

Forty-eight articles were included in the systematic review. Overall prevalences were: TMDs-15% (95% CI: 15-16%); TMD pain-8% (95% CI: 7-9%); TMJ sounds-24% (95% CI: 21-27%); and TMJ locking-7% (95% CI: 1-13%). While TMD prevalence appeared to have declined from 2002 to 2011 to 2012-2021, the occurrence of TMD pain, TMJ sounds, and locking increased marginally or remained constant. TMD prevalence in children/adolescents was 18% (95% CI: 14-22%) and 17% (95% CI: 16-18%) among adults. Significant associations between TMDs and bruxism/psychological distress/education levels were specified by 73%/90%/88% of the relevant studies.

CONCLUSIONS

TMDs are prevalent in CHCs and a slight increase in TMD pain (2%) and TMJ sounds (8%) were discerned over the past two decades. TMDs are related to a myriad of biopsychosocial variables, particularly psychological distress, and these factors must be addressed within the cultural context of patients.

Exploring Temporomandibular Disorders (TMDs) and Occlusion Debate in Dentistry: Biting Into Controversy

Some conditions known as temporomandibular disorders (TMDs) affect surrounding muscles and jaw joints. In dentistry, there has been discussion and research on the connection between TMDs and occlusion, which is how the upper and lower teeth meet. Although some dental experts have proposed a direct link between TMDs and occlusion, the specifics of this relationship are still unclear and have many facets. More particularly, the research facets of "occlusion" remain one of the most contentious subjects in TMDs. This abstract aims to provide an overview of TMDs and occlusion, summarizing the key points from the literature. The etiological factors contributing to the TMDs, including occlusal, psychological, and hormonal factors, are also analyzed. The second part of the article includes the concept of malocclusion, emphasizing its significance in masticatory function and overall health. Anterior open and posterior open bites and the potential influence of occlusal factors on TMDs are elucidated.

Temporomandibular disorder symptoms and their association with quality of life of dental patients in Malaysia

OBJECTIVE

To assess the prevalence of temporomandibular disorders (TMD) and their effects on quality of life (QoL) of dental patients.

METHODS

A survey consisting of two validated questionnaires was distributed to dental patients registered at the University of Malaya Faculty of Dentistry. The Fonseca Anamnestic Index (FAI) evaluates the prevalence and severity of TMD, while the Oral Health Impact Profile - Temporomandibular Disorder (OHIP-TMD) appraises the effects of TMD on oral health-related QoL.

RESULTS

Out of 342 patients (aged 16 to 50 years, 45% male and 55% female) enrolled in the survey, 50.9% had varying degrees of TMD. All 7 domains of OHIP-TMD showed a statistically significant correlation with TMD severity.

CONCLUSION

TMD seems to be prevalent among Malaysian dental patients. Not only does TMD affect the QoL of an individual, but the more severe the degree of reported symptoms, the poorer their perceived oral health QoL.

Psoriatic Arthritis Involving TMJ: A Review on Pathogenesis and Consideration on Eventual Gender Differences

Psoriatic arthritis is defined as chronic inflammatory arthritis associated with psoriasis. The current data regarding gender differences in clinical manifestation and therapeutic outcomes of psoriatic arthritis are limited. Generally, men show a peripheral disease manifestation, while women have an axial distribution of the lesions. If we look at temporomandibular joint (TMJ) involvement, epidemiological data on the involvement of the TMJ are hard to find. Few studies on therapeutic management and the related impact on the quality of life are reported in the literature. Given the morpho-functional peculiarities of the TMJ and the different pain burdens between male and female genders, when manifestation of psoriatic arthritis occurs, clinicians should face it using a multidisciplinary approach for a correct diagnosis and successful treatment. This review aims to examine the diagnostic signs of psoriatic arthritis in the TMJ, the eventual variations of this disease in male and female patients, and the therapeutical strategies. The coordination of different specialties is fundamental to the remission of clinical symptoms and lesion regression.

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.

Primary headaches in scuba divers and the effect of temporomandibular dysfunction

OBJECTIVE

This study aimed to evaluate the frequency of episodic primary headaches (EPH) and temporomandibular dysfunction's (TMD) effect in experienced scuba divers.

METHODS

A form consisting of the Fonseca Anamnestic Index and a structured headache questionnaire was sent to individuals using social media platforms.

RESULTS

A total of 132 divers and 104 non-divers were included the study. In male divers, EPH and TMD were not different from the non-diver group (p = 0.1, p = 0.1), and TMD had an effect on increasing the possibility of migraine (OR = 2.5, p = 0.04). In female divers, the possibility of EPH and TMD were also lower (OR = 0.1, p < 0.001, OR = 0.2, p = 0.01).

CONCLUSION

Scuba diving does not pose a risk for EPH or TMD in either gender. TMD treatment in male divers is important for uncontrolled migraine attacks.

Is acupuncture an effective treatment for temporomandibular disorder?: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Acupuncture is used for treating various disorders, but its effects on temporomandibular disorder (TMD) remain unclear. This study aimed to assess the effectiveness and safety of acupuncture for TMD via a systematic review of randomized clinical trials.

METHODS

A total of 11 Korean and worldwide databases were searched to identify acupuncture studies in adults with TMD. A Cochrane risk of bias assessment was performed on all articles; a meta-analysis, which involved the categorization according to the type of control used (inactive control, active control, or add-on), was subsequently performed. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation methodology.

RESULTS

The qualitative analysis of randomized clinical trials with acupuncture as the intervention included 32 articles, 22 of which were included in the quantitative analysis (471 participants). Acupuncture significantly improved outcomes (effect rate, relative risk [RR]: 7.00, 95% confidence interval [CI]: 1.91, 25, 62; visual analog scale, standardized mean difference: 0.49, 95% CI: 0.24, 0.73) versus active controls (effect rate, RR: 1.19; 95% CI: 1.12, 1.27). In the analysis of add-ons, acupuncture significantly improved the effect rate and pain intensity (effect rate, RR: 1.36; 95% CI: 1.04, 1.77; visual analog scale, mean difference: -1.23; 95% CI -1.79, -0.67). However, the quality of evidence was determined to range from low to very low.

CONCLUSION

Acupuncture in TMD significantly improved outcomes versus active controls and when add-on treatments were applied. However, as the quality of evidence was determined to be low, well-designed clinical trials should be conducted in the future.

Artificial intelligence for detecting temporomandibular joint osteoarthritis using radiographic image data: A systematic review and meta-analysis of diagnostic test accuracy

In this review, we assessed the diagnostic efficiency of artificial intelligence (AI) models in detecting temporomandibular joint osteoarthritis (TMJOA) using radiographic imaging data. Based upon the PRISMA guidelines, a systematic review of studies published between January 2010 and January 2023 was conducted using PubMed, Web of Science, Scopus, and Embase. Articles on the accuracy of AI to detect TMJOA or degenerative changes by radiographic imaging were selected. The characteristics and diagnostic information of each article were extracted. The quality of studies was assessed by the QUADAS-2 tool. Pooled data for sensitivity, specificity, and summary receiver operating characteristic curve (SROC) were calculated. Of 513 records identified through a database search, six met the inclusion criteria and were collected. The pooled sensitivity, specificity, and area under the curve (AUC) were 80%, 90%, and 92%, respectively. Substantial heterogeneity between AI models mainly arose from imaging modality, ethnicity, sex, techniques of AI, and sample size. This article confirmed AI models have enormous potential for diagnosing TMJOA automatically through radiographic imaging. Therefore, AI models appear to have enormous potential to diagnose TMJOA automatically using radiographic images. However, further studies are needed to evaluate AI more thoroughly.

Temporomandibular Disorders as a Risk Factor for Suicidal Behavior: A Systematic Review

BACKGROUND

Temporomandibular disorders (TMD) are a group of common musculoskeletal dysfunctions that affect the temporomandibular joint or masticatory muscles and related structures or are expressed as a clinical combination of these two factors. The etiology of TMD is multifactorial and features related to anxiety, depression and mental disorders can contribute to the predisposition, onset and progression of TMD. The ability to adapt and develop coping attitudes was reduced in patients presenting with chronic pain, while suicidal behavior (suicidal ideation, suicide attempts, and suicide completion) was increased. The objective of this review was therefore to investigate suicidal behavior in relation to TMD.

METHODS

The review was performed according to the PRISMA 2020 guidelines. Six databases (PubMed, MEDLINE, EMBASE, Scopus, Ovid, and Google Scholar) were consulted through the use of keywords related to the review topic. The study is registered on PROSPERO (CRD42022320828).

RESULTS

The preliminary systematic search of the literature yielded 267 records. Excluding duplicates, 15 were considered potentially relevant and kept for title and abstract analysis. Only six articles were considered admissible reporting a single exposure factor, TMD and a single outcome, suicidal behavior, although these were evaluated through different assessment tools. We found a low association of TMD with suicidal behavior in observational studies, with estimates partly provided [prevalence ratio (PR) from 1.26 to 1.35, 95% confidence intervals (CI) from 1.15 to 1.19 (lower) and from 1.37 to 1.54 (higher); and odds ratios (OR) from 1.54 to 2.56, 95% CI from 1.014 to 1.157 (lower) and 2.051 to 6.484 (higher)], a relevant sample size (n = 44,645), but a few studies included (n = 6).

CONCLUSIONS

The results of the included studies showed that the prevalence data of suicidal behavior were more present in young adults with TMD, with a controversial association with gender. Suicidal behavior was also correlated and aggravated by the intensity of pain.

Gender Disparity and the Association Between Socioeconomic Status, Mental Health, and the Need for Long-Term Services and Support Among the Older Koreans

Background

Population aging-the inevitable increase in the percentage of older adults-is occurring all around the world as the fertility rate declines and life expectancy rises. This study examined the relationship between socioeconomic status (SES), mental health, and the need for long-term services and support (LTSS) among Korean older adults. It also aimed to provide evidence-based information for South Korea's long-term support services and programs.

Methods

This study used the data on older adults aged over 60 years from the 2018 Korean Longitudinal Study of Aging (KLoSA). Ultimately, 5,527 older adults were included in the database (42.6% men, 57.4% women). To clarify the association between SES, mental health, and the need for LTSS among older Korean men and women, chi-squared test, t-test, and structural equation modeling (SEM) were performed.

Results

The SEM analysis showed that a significant, negative association was observed between SES and the need for LTSS among these older adults-the higher SES groups would generally have less need for LTSS. Mental health had a strong, negative impact on the need for LTSS-better mental health status of the older individuals would indicate a lower need for LTSS, and the effect was stronger among older men. Meanwhile, the positive relationship between SES and mental health was verified-the higher the SES of these older adults the better their mental health.

Conclusions

Gender- and social class-sensitive impacts of mental health on the need for LTSS were observed in this study. These findings could provide an evidence-based reference for interventions targeting different genders and social classes in Korea's long-term care system, such as the enhancement of social welfare and mental health status of the older adults.

Effects of Occlusal Splints on Spinal Posture in Patients with Temporomandibular Disorders: A Systematic Review

There is still a gap in the scientific knowledge on the linkage between craniofacial structure and spinal postural control in temporomandibular disorder (TMD) patients. This systematic review aimed to assess the role of occlusal splints on spinal posture of TMD patients. PubMed, Web of Science, and Scopus were systematically searched from inception until 5 January 2022 to identify observational studies with a longitudinal study design presenting: patients with diagnosis of TMD according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD); occlusal splint therapy as intervention; postural assessment as outcome. Out of 133 records identified, 104 were suitable for data screening, and only 7 articles were included satisfying the eligibility criteria. We found that occlusal splints might have a positive effect on posture in TMD patients, albeit there is little evidence of appropriate investigation for postural assessment. This systematic review suggested that the occlusal splint might be considered a non-invasive therapeutic approach for patients with TMD. However, the low number of studies with high-quality methodology in these patients showed an urgent need for further research using combined force platform stabilometry and kinematic evaluation of the spine to investigate the impact of occlusal splints on posture.

The effect of functional mandibular advancement for adolescent patients with skeletal class II malocclusion on the TMJ: a systematic review and meta-analysis

OBJECTIVES

This study aimed to assess whether functional mandibular advancement (FMA) will cause temporomandibular joint disorders (TMD) or have side effects on temporomandibular joint (TMJ) in adolescent patients.

METHODS

All searched databases, including PubMed, Web of Science, EMBASE, Cochrane Central Register of Controlled Trails and Scopus were searched. Gray literature and unpublished literature was also searched. Randomized controlled trails (RCT) and non-randomized studies of the effects of interventions (NRSI) directly observe the condition of adolescent patients' TMJ after finishing treatment will be considered to include in our study. According to Cochrane Handbook, Cochrane Collaboration risk of bias tool was used to assess the quality of included RCTs, and Risk of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool was used to assess the quality of included NRSIs.

RESULT

Finally 18 researches were evaluated as eligible to include in this study. 5 of the studies were RCTs, 8 were NRSIs and 5 were systematic reviews. The data of RCTs and NRSIs were statistically pooled in meta-analysis. The number of samples under investigated among primary studies was 579 individuals,there were 80 patients who developed temporomandibular symptoms during or after treatment. But all the subjective symptoms disappeared during follow-up time. The statistical outcomes proved that patients received FMA didn't show more tendency to develop temporomandibular symptoms [I2 = 27%, OR = 0.54, 95%CI (0.33,0.87), p = 0.01].

CONCLUSION

(1) TMJ symptoms may occur during the functional oral appliance wearing, but the symptoms will release or disappear after treatment or during the follow-up period. (2) Less convincing evidence indicates that slightly previous TMD and condyle-glenoid fossa relationship will be improved after treatment. (3) There is TMJ disc anterior displacement observed during treatment, but most of them will return to the normal position later. (4) Moderate evidence support that FMA will not have side effects on TMJ of adolescent patients.

Sociodemographic trends in a UK temporomandibular joint disorder clinic

Introduction Temporomandibular disorders (TMD) are a common source of facial pain, resulting from an interaction of biopsychosocial factors. However, social risk factors related to TMD have been researched very little, particularly in patients attending a tertiary care service.Aims To review sociodemographic trends among patients referred to a UK tertiary TMD clinic for specialist management. To provide an insight into the sociodemographic risk factors associated with TMD in patients referred for specialist input and to discuss the surrounding literature.Methods Retrospective review of notes of patients referred to a UK tertiary TMD clinic. Trends in areas of deprivation from which patients came from were quantified into deciles using the English Multiple Indices of Deprivation.Results The mean age of patients was 41.1 years, with women being overrepresented compared to men. Most patients were referred by their general dental practitioner, although a variety of secondary care specialties also referred to this service. A disproportionate number of patients came from the highest decile of deprivation, a trend seen throughout the entire sample and in patients seen by dental professionals specifically. There was no apparent association between this and longer symptom duration.Conclusion Women and those from areas with the highest levels of deprivation were overrepresented in this tertiary clinic setting. Dentists should maintain an awareness of the risk factors for TMD development as well as those which may complicate its management in cases requiring specialist input.

TMD in Females with Menstrual Disorders

BACKGROUND

Temporomandibular disorders (TMD) are a common reason for patients to present at dental offices. The majority of people with TMD are women between the age of 20 and 40 years. The purpose of this study was to assess the types and prevalence of temporomandibular disorders in female patients of reproductive age with menstrual disorders.

MATERIALS AND METHODS

The study involved 65 females of reproductive age (18-40 years, an average of 28.00 ± 6.27 years). The women who qualified for the study were patients of the University Center for Maternal and Newborn's Health hospitalized because of infertility or menstrual cycle disorders. Women with confirmed estrogen metabolism disorders participated in a clinical study with the use of Diagnostic Criteria for Temporomandibular Disorders (DC/TMD).

RESULTS

In the studied female patients with menstrual disorders, temporomandibular disorders (92.3%) were frequent occurrences. The most common type was intra-articular joint disorders (68%). Other reported complaints included masticatory muscle pain (44.62%), and degenerative joint diseases (12.3%).

CONCLUSIONS

1. In women with menstrual disorders, TMD may exist. 2. In women with TMD symptoms, their medical history should be extended to include the diagnosis of female hormone disorders.

A Female Psoriatic Arthritis Patient Involving the TMJ

Psoriatic arthritis (PsA) is an inflammatory chronic arthritis associated with psoriasis. Currently, data about gender differences in clinical manifestation and therapeutic outcomes of PsA are limited. Frequently, women manifest a peripheral disease while men have an axial localization. Moreover, women display higher disease activity and physical activity limitations, if compared to men. Although the involvement of the temporomandibular joint (TMJ) is quite rare, it can seriously impact the quality of life. The morpho-functional peculiarities of TMJ require a multidisciplinary approach to perform a correct diagnosis and a successful treatment. Here, we report a case of a woman affected by PsA involving TMJ treated by combining pharmacological therapy and an occlusal splint. The coordination between different specialties led to a complete remission of clinical symptoms and a regression of lesions.

Mapping research trends of temporomandibular disorders from 2010 to 2019: A bibliometric analysis

BACKGROUND

Because of various clinical manifestations and complicated courses, temporomandibular disorders (TMDs) are difficult to treat. Current knowledge about this disease remains insufficient for precise treatment after diagnosis.

OBJECTIVES

The objective of this study is to obtain and map the overall literature trends and most cited keywords in TMDs research.

METHODS

Many indicators, including annual number of publications, country distribution, global cooperations, author contributions, original journals, cited references and keywords, were calculated and evaluated using VOSviewer v.1.6.13, which visualised many results, from the WoSCC database.

RESULTS

A total of 3121 papers on TMDs research were retrieved from 2010 to 2019. The United States produced the most articles published, but the most productive institution was the University of Sao Paulo (Brazil). Researchers and institutions conducting TMDs research have shown a very widespread and close connection. TMDs have been studied worldwide by many research centres. Professor Svensson P was the most published researcher in TMDs research and the Journal of Oral Rehabilitation published the most TMDs research articles. The top cited references mainly presented diagnostic criteria of TMDs. The most cited keywords formed clusters: (a) Anatomical factor of TMDs, (b) Symptoms of TMDs and (c) RDC/TMD, the risk factors, biopsychosocial factors and epidemiology of TMDs.

CONCLUSIONS

The research results provide very valuable data for a thorough understanding of the research status of TMDs and demonstrated international cooperation.

Evaluation of temporomandibular disorders, quality of life, and oral habits among dentistry students

Objective: To evaluate temporomandibular disorders (TMD), quality of life, and oral habits in dentistry students.Methods: The study was performed with 480 students (287 females, 193 males). The Fonseca Questionnaire, Oral Health Impact Profile-14 (OHIP-14), and Oral Behaviors Checklist (OBC) were used.Results: The mean scores of the fifth-year students from Fonseca TMD, OHIP-14, and OBC were statistically significantly higher than those of the students in other years of study. The mean Fonseca score of female students was higher than those of the males. There was a statistically significant difference regarding the OHIP-14 scores based on the Fonseca TMD scores. A statistically significant difference regarding OBC was present based on the Fonseca TMD scores.Conclusion: The prevalence of TMDs was higher among the senior dentistry students. Necessary measures should be taken in the dentistry educational system to raise students' quality of life, improve joint disorders, and eliminate current oral habits.

Efficacy of occlusal splints in the treatment of temporomandibular disorders: a systematic review of randomized controlled trials

OBJECTIVE

This systematic review aimed to assess the efficacy of occlusal splints in the treatment of temporomandibular disorders (TMDs).

MATERIAL AND METHODS

This systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Four databases (Medline via Pubmed, Web of Science, Embase and Scopus) were searched, the last search was conducted on April 2020. Randomised controlled trials (RCTs) employing the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) or Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) as diagnostic criteria and including occlusal splint as one of the experimental groups were included in the present study. The data from the included studies were extracted and assessed for risk of bias.

RESULTS

Eleven studies were included. The sample size ranged from 12 to 96 subjects. The male to female ratio was 0 to 25%. The mean length of follow-up was 4 months. Occlusal splint had a positive effect on mandibular movements in all included studies. Seven studies showed a positive effect of occlusal splint on chronic pain reduction and pain intensity, while two others showed improvement of temporomandibular joint clicking sounds and locking of the jaws. Moreover, improvements in mouth opening, depression, and anxiety symptoms, were reported in four studies.

CONCLUSIONS

An occlusal splint can be considered as a non-invasive treatment approach for patients with TMD, especially those with signs and symptoms of restriction of mandibular movement and pain. Moreover, the present findings highlighted an urgent need of a standardised consensus regarding the prognostic evaluation of TMD.

A novel mobile application to determine mandibular and tongue laterality discrimination in women with chronic temporomandibular disorder

Background

Chronic pain from temporomandibular disorders (TMDs) is caused by a somatosensory disturbance due to sustained activation of central nervous system nociceptive pathways, which can induce changes in neuroplasticity in the thalamus, basal ganglia and limbic system, as well as disturbances in the somatosensory, prefrontal and orbitofrontal cortex and cognitive impairment. The main objective of this study was to determine the discrimination capacity of mandibular and tongue laterality between women with chronic TMDs and asymptomatic women.

Material and Methods

This descriptive-comparative study examined 2 groups with a total of 30 women. All participants were between the ages of 23 and 66 years and were assigned to the chronic TMD group or the asymptomatic group according to the inclusion criteria. We employed a mobile application developed specifically for this study to measure the accuracy and reaction time (RT) of mandibular and tongue laterality discrimination.

Results

The chronic TMD group had a lower success rate in laterality discrimination (mean mandibular accuracy of 40% and mean tongue accuracy of 67%) than the asymptomatic group (mean mandibular accuracy of 61% and mean tongue accuracy of 90%). These results showed statistically significant differences between the groups for mandibular laterality discrimination (d, 1.14; p<0.01) and tongue laterality discrimination (d, 0.79; p=0.03). The asymptomatic group had faster RTs than the chronic TMD group. The data revealed statistically significant differences for the right mandibular RT (d, 0.89; p=0.02) and right tongue RT (d, 0.83; p=0.03). However, there were no significant differences for left mandibular and left tongue RT.

Conclusions

We found that the women with chronic TMDs had a lower success rate and slower RTs in the discrimination of mandibular laterality when compared with the asymptomatic women.

Key words:Mobile application, tongue, chronic temporomandibular disorder, pain, lateral discrimination, cortical representation, reaction time.

Healthcare utilisation and costs for temporomandibular disorders: a descriptive, cross-sectional study

OBJECTIVE

Temporomandibular joint disorder (TMD) requires long-term management and can be a financial burden for patients. Here, we investigated the treatment received by people diagnosed with TMD and its relevant costs.

DESIGN

A descriptive, cross-sectional study.

SETTING AND PARTICIPANTS

We performed secondary data analysis of health insurance claims data provided by the Health Insurance Assessment and Review (HIRA) of the Republic of Korea. We reviewed the records of 10 041 patients who were diagnosed with TMD and who utilised outpatient healthcare service at least once between January and December 2017.

PRIMARY AND SECONDARY OUTCOME MEASURES

Data on use of medical services, hospitalisations, sociodemographic factors, treatment and medication were retrieved and analysed. Cost was defined as the cost of care incurred by a health insurance beneficiary at a care facility.

RESULTS

We reported the characteristics as medians, frequencies and percentages and found that most TMD patients were outpatients, women (58.9%) and in their 20s (46.4%). For visit type, 85.9% of all patients had an outpatient dental medical visit, with most visiting dental clinics and dental hospitals. Western medicine (WM; 9.8%) was prescribed more often, followed by Korean medicine (KM; 8.2%). The median expense per patient was highest among those in their 20s (58.00, 23.90, 53.40, 65.90 US$ for overall, WM, dental medicine (DM) and KM, respectively). Consultation fees accounted for the greatest percentage (42.8%) of DM and WM care expenses, while injection/non-surgical intervention fees accounted for the greatest percentage of KM care expenses. The most commonly used treatments for TMD were temporomandibular joint stimulation therapy (51.1%) and acupuncture (19.9%), considered as the most basic care for TMD. Psychosomatic agents (86.4%) were the most commonly used medications in outpatients.

CONCLUSIONS

While people with TMD most commonly received temporomandibular stimulation therapy, the costs and duration of treatment varied significantly for these patients.

Impact of prolotherapy in temporomandibular joint disorder: a quality of life assessment

Chronic pain and functional impairment associated with temporomandibular joint (TMJ) disorders (TMD) considerably reduce oral health-related quality of life (OHRQoL). In the present study we have assessed the influence of prolotherapy in patients with TMD by the subjective measurement of QoL using the Oral Health Impact Profile-14 (OHIP-14). Twenty-five patients diagnosed with TMD (mean (range) age 38 (18 - 70) years) were included. They had all undergone dextrose prolotherapy to the TMJ at regular time intervals (four times at intervals of two weeks) using the method suggested by Hemwall-Hackett. They were asked to answer the OHIP-14 questionnaire before and two years after prolotherapy. Seven domains of OHRQoL were rated on a 5-point Likert scale from 0 (never) to 4 (very often). Domain scores and total OHIP-14 scores were compared using inferential statistics (chi squared and Wilcoxon signed rank tests). Prolotherapy was effective over time, as all the domains' mean scores decreased considerably after treatment. The total mean score before prolotherapy was 21.20, which was extensively reduced to 13.08 after prolotherapy (p=0.001). There was statistically significant improvement in all domains, including functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap (p≤0.005 in all cases). We concluded that prolotherapy has a promising role in the improvement of OHRQoL of patients with TMD, and its beneficial effects persist at least two years after treatment.

Women’s oral health-related quality of life as a risk factor for TMD symptoms. A case-control study

OBJECTIVE

To investigate the association between temporomandibular disorder (TMD) symptoms and women's oral health-related quality of life (OHRQoL).Methods: An observational case-control study was performed with 765 adult women aged 21.5 years on average. Oral Health Impact Profile (OHIP-14) assessed OHRQoL and determined the selection of cases and controls matched by age and marital status at a ratio of 1:4 (153 cases: 612 controls). American Academy of Orofacial Pain's self-explanatory questionnaire assessed the TMD symptoms. The TMD symptoms' impact on OHRQoL was analyzed, estimating the odds ratio with a 95% confidence interval.

RESULTS

Of the women, 86.9% in the case group, and 69.6% in the control group presented some TMD symptoms (p< 0.05). Women with an impacted OHRQoL are 2.95 (95% CI:1.79-4.86) times more likely to report some TMD symptoms (p< 0.05).

DISCUSSION

Women with a negative impact on OHRQoL are more likely to report TMD symptoms.

Progesterone Attenuates Allodynia of Inflamed Temporomandibular Joint through Modulating Voltage-Gated Sodium Channel 1.7 in Trigeminal Ganglion

Background

Women with temporomandibular disorders (TMDs) experience some amelioration of pain during pregnancy. Progesterone increases dramatically and steadily during pregnancy. Sodium channel 1.7 (Nav1.7) plays a prominent role in pain perceptions, as evidenced by deletion of Nav1.7 alone leading to a complete loss of pain. In a previous study, we showed that Nav1.7 in trigeminal ganglion (TG) is involved in allodynia of inflamed temporomandibular joint (TMJ). Whether progesterone modulates allodynia of inflamed TMJ through Nav1.7 in TG remains to be investigated.

Methods

The effects of progesterone on sodium currents of freshly isolated TG neurons were examined using whole-cell recording. Female rats were ovariectomized and treated with increasing doses of progesterone for 10 days. Complete Freund's adjuvant was administered intra-articularly to induce TMJ inflammation. TMJ nociceptive responses were evaluated by head withdrawal thresholds. Real-time PCR and Western blotting were used to examine Nav1.7 mRNA and protein expression in TG. Immunohistofluorescence was used to examine the colocalization of progesterone receptors (PRα/β) and Nav1.7 in TG.

Results

Whole-cell recording showed that progesterone could attenuate sodium currents. Moreover, progesterone dose-dependently downregulated Nav1.7 mRNA expression and reduced the sensitivity of TMJ nociception in ovariectomized rats. Furthermore, treatment with progesterone attenuated allodynia of inflamed TMJ in a dose-dependent manner and repressed inflammation-induced Nav1.7 mRNA and protein expression in ovariectomized rats. The progesterone receptor antagonist, RU-486, partially reversed the effect of progesterone on allodynia of inflamed TMJ and TMJ inflammation-induced Nav1.7 mRNA and protein expression.

Conclusion

Progesterone, by modulating trigeminal ganglionic Nav1.7, may represent a promising agent to prevent allodynia of inflamed TMJ.

Platelet Concentrate Treatments for Temporomandibular Disorders: A Systematic Review and Meta-analysis

OBJECTIVES

This systematic review compared platelet concentrates (PCs) versus hyaluronic acid (HA) or saline/Ringer's solution injections as treatments of temporomandibular osteoarthritis and disc displacement in terms of pain and maximum mouth opening (MMO).

METHODS

PubMed, Cochrane, and Scopus were searched up to March 6, 2020. Inclusion criteria were randomized clinical trials (RCTs). Exclusion criteria were case series, observational studies, animal studies, and reviews. The Effective Public Health Practice Project (EPHPP) quality assessment tool was used to assess the risk of bias in the included studies. The weighted mean difference was used to compare the results.

RESULTS

Nine RCTs were included with a total of 407 patients. The numbers of joints treated were 262, 112, and 112 in the PC, HA, and saline groups, respectively. The quality of studies was rated as strong in 4 studies, moderate in 4 studies, and weak in 1 study. The meta-analysis revealed that PCs decreased pain visual analogue scale (VAS) scores compared to HA by an average of -1.11 (CI, -1.62 to -0.60; P < 0.0001) and -0.57 (CI, -1.55 to 0.41; P = 0.26) at 3 and 12 mo follow-up respectively. Also, the average decrease in pain scores with PC compared to saline was -1.33 (CI, -2.61 to -0.06; P = 0.04), -2.07 (CI, -3.46 to -0.69; P = 0.003), and -2.71 (CI, -4.69 to -0.72; P = 0.008) at 3, 6, and 12 mo, respectively. Regarding MMO measurements, PC was comparable to HA, but it was significantly better than saline after 3 and 6 mo [2.9 mm (CI,1.47 to 4.3; P < 0.0001), and 1.69 mm (CI, 0.13 to 3.25; P = 0.03) respectively].

CONCLUSION

PC reduces pain VAS scores compared to HA during the first 3 m after treatment, and when compared to saline, it reduces pain and increases MMO for longer durations. However, due to differences between groups regarding PC preparation protocols and study heterogeneity, further standardized RCTs are required.

KNOWLEDGE TRANSFER STATEMENT

This study provides researchers and clinicians with quantitative and qualitative analyses of the current evidence regarding the clinical outcomes of platelet concentrate injections in the treatment of temporomandibular joint osteoarthritis and disc displacement in terms of pain control and maximum mouth opening.

Frequency distribution of temporomandibular disorders according to occlusal factors: A cross-sectional study

BACKGROUND

Temporomandibular disorder (TMD) is a common condition affecting the temporomandibular joint and causes pain and discomfort. However, the role of factors contributing to this problem is still controversial. The purpose of this cross-sectional study was to determine the correlation of occlusal factors and parafunctional habits with TMD and The determination of TMD prevalence among patients referring to Isfahan Dental School in 2017.

MATERIALS AND METHODS

In this cross-sectional study, A total of 200 patients between 20 and 50 years were examined and questioned based on the Research Diagnostic Criteria for Temporomandibular Disorders assessment instrument. The association of occlusal factors (dental relationship, lateral occlusal scheme, horizontal differences between centric occlusion and Maximum intercuspation (MI), difference between MI and mandibular resting position) and parafunctional habits (bruxism/clenching and habits) with TMD was analyzed using Chi-square tests and independent sample t-test (α = 0.05). Binomial logistic regression analysis was performed with respect to confounding variables.

RESULTS

The prevalence of TMD in the studied sample was 58.9%. Only bruxism showed a significant difference between TMD and non-TMD groups (P < 0.05). Other parafunctional and occlusal factors did not act as influential factors for TMD.

CONCLUSION

Parafunction may play an important role in the initiation of TMD, although other habits and occlusal factors are considered as noninfluential factors. However, larger sample size and multicenter sampling are recommended for the future studies.

The impact of chronic orofacial pain on health-related quality of life

Background and aims

Health-related quality of life (HRQoL) assessments have been widely used in pain medicine as they are able to reflect the subjective and multidimensional nature of chronic pain. Studies have shown a consistent impairment in HRQoL in different chronic pain conditions. However, it is not known whether HRQoL is impaired in chronic orofacial pain (OFP). The generic 15D HRQoL instrument has been shown to fare as well as or better than other generic HRQoL instruments in the study of chronic pain. The aim was to investigate HRQoL in patients with chronic OFP using the generic 15D HRQoL instrument. The validity of the instrument was tested by studying the association of the 15D data with pain interference.

Methods

One hundred fifty-one patients (mean age 50 years, SD 15 years, 119 females) were recruited from three tertiary facial pain clinics. HRQoL data of the participants were contrasted with that of an age- and gender- standardized sample of general population by comparing the mean 15D scores and profiles. The data for the general population came from the National Health 2011 Survey representing Finnish population aged 18 years and older. Pain interference was assessed using Brief Pain Inventory. Based on pain interference distribution the participants were divided into tertiles. Statistical comparison between patient and population HRQoL values were performed using Monte-Carlo-type simulations. Statistical significance for the hypothesis of linearity was evaluated by using generalized linear models.

Results

The mean 15D score of OFP patients (0.824, SD 0.113) was statistically significantly lower than that of the age- and gender-standardized general population (0.929, SD 0.019) (p < 0.001). The difference between the patients and the general population was also clinically important, i.e. over the minimum clinically important difference in the 15D score. All mean 15D dimension values were significantly lower compared with the general population values (p < 0.001 for all dimensions). The largest differences were seen in the dimensions of discomfort and symptoms (0.418, SD 0.222 vs. 0.816, SD 0.027), sleeping (0.693, SD 0.258 vs. 0.838, SD 0.029), and vitality (0.702, SD 0.221 vs. 0.884 SD 0.026). There was a statistically significant linear decrease in the 15D dimension values (p < 0.001) with increasing pain interference. The greatest differences were found on the dimensions of discomfort and symptoms, sleeping and vitality.

Conclusions

HRQoL is significantly impaired in patients with chronic OFP. A decrease in the 15D dimension values with increasing pain interference indicated convergent validity between 15D and pain interference.

Implications

The findings suggest that 15D is an appropriate instrument for use in the assessment of HRQoL in OFP patients. By showing the usefulness of the 15D, the present study may encourage further use of generic HRQoL assessments in the study of chronic OFP, and contribute e.g. to the implementation of HRQoL as one of the core outcome measures in future treatment studies on chronic OFP.

Evaluation of temporomandibular disorder symptoms and oral health-related quality of life in adolescent orthodontic patients with different dental malocclusions

Objective: To estimate the prevalence of temporomandibular disorders in adolescent orthodontic patients with different dental malocclusions and to assess the relationship between oral health-related quality of life.Methods: This study was carried out on 648 randomly selected individuals 14-19 years of age. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), Fonseca Questionnaire, and Oral Health Impact Profile-14 (OHIP-14) forms were used.Results: TheGCPS,TMDPain,Fonseca,OHIP-14, PHQ-9, GAD-7,OBC,andPHQ-15 mean scores of female participants were statistically significantly higher than males (p < 0.05).There was a significant difference among the malocclusion groups in terms of their mean scores in GCPS, Fonseca, and OHIP-14 (p < 0.05).The age values and JFLS, TMD Pain, Fonseca, OHIP-14, PHQ-9, GAD-7, and PHQ-15 were statistically significant correlations in the positive direction.Conclusion: The DC/TMD form allows both a physical assessment of Axis I and II that examines psychosocial status and pain-related disorders and a more comprehensive assessment. The mean OHIP-14 and Fonseca questionnaire scores of Class III groups were found to be significantly higher.

Increased Oral Health-Related Quality of Life Postsynergistic Treatment with Ultrasound and Photobiomodulation Therapy in Patients with Temporomandibular Disorders

Background and objective: The object of this study was to analyze the oral health-related quality of life (OHRQoL) of patients with temporomandibular disorders (TMDs) who were treated simultaneously with ultrasound (US) and photobiomodulation therapy (PBMT). Materials and methods: This study included 13 patients of both genders, with diagnosis of TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders. The patients were treated with equipment consisting of US and PBMT in the same system. The treatment was applied to the left and right sides of the face in the masseter muscle, anterior temporalis muscle, and temporomandibular joint, two sessions per week for a total of eight sessions. The OHRQoL was assessed by the Oral Health Impact Profile (OHIP-14) at three moments: pretreatment (T₀), after the eight treatment sessions (T₁), and 30 days after termination of treatment (T₂). The Wilcoxon, Mann-Whitney U, Kruskall-Wallis, and Spearman's correlation coefficient tests were applied, with a significance threshold of 5%. Results: Psychological discomfort, physical pain, and psychological limitation were the domains where the highest scores were obtained at T₀. The total OHIP-14 scores at T₁ and T₂ were significantly lower than at T₀. No statistical differences were observed between T₁ and T₂. Conclusions: We conclude that synergistic treatment was effective in improving the OHRQoL of patients with TMDs, and that its beneficial effects persisted at 1 month after termination of treatment.

The many faces of genetic contributions to temporomandibular joint disorder: An updated review

OBJECTIVES

The aim was to review the literature regarding genetic contributions to temporomandibular joint disorder (TMD) after our 2008 publication.

SETTING AND SAMPLE POPULATION

Literature review.

MATERIAL AND METHODS

PubMed and MEDLINE were used to obtain literature in any language regarding genes and TMD, using the keywords "temporomandibular joint disorder" and "temporomandibular joint dysfunction" for studies published from 2009 to 2017.

RESULTS

In our search, 274 studies were found. We excluded 76 studies from animal models, 22 studies that were in vitro and 120 reports that were not cohort or case-control studies. Of the 274 results, 56 articles were selected for this review. Genes that are suggested to contribute to TMD included the ones related to disc and bone alterations as well as pain sensation.

CONCLUSION

Currently, no evidence of associated genetic variants, which can determine the development of TMD in individuals, could be translated to novel clinical management and public health strategies for patients suffering from TMD.

Prevalence of diagnosed temporomandibular disorders: A cross-sectional study in Brazilian adolescents

Background

The prevalence of signs and symptoms of temporomandibular disorders (TMD) increases during adolescence and adulthood. Few studies have examined TMD prevalence in Brazilian adolescents.

Aim

To investigate the prevalence of TMD in Brazilian adolescents.

Methods

A representative population-based sample of 934 adolescents (10–14-years-old) was examined. TMD screening was performed using a questionnaire by the American Academy of Orofacial Pain. TMD diagnoses used research diagnostic criteria for temporomandibular disorders (RDC/TMD—Axis-I). Examinations were performed by a single calibrated examiner (kappa > 0.80).

Results

The prevalence of TMD symptoms was 34.9%; the most frequently reported symptoms were headache and neck ache (20.9%), followed by joint sounds (18.5%). Myofascial pain was the most prevalent type (10.3%), followed by disc displacement with reduction (8.0%) and arthralgia (3.5%). There was a significant association between sex and TMD symptoms; prevalence was significantly higher in girls (RP = 1.37; 95% CI = 1.14–1.65; p = 0.001). Myofascial pain of TMD and displacement with reduction were more prevalent in girls (RP = 1.76; p = 0.007 and RP = 2.06; p = 0.004, respectively).

Conclusion

TMD symptoms were present in 34.9% of adolescents, with myofascial pain being the most prevalent type (10.3%). TMD was significantly more common in girls. Routine pediatric dental care should include a TMD screening.

Association between temporomandibular disorders, chronic diseases, and ophthalmologic and otolaryngologic disorders in Korean adults: A cross-sectional study

INTRODUCTION

Temporomandibular disorders (TMDs) are common musculoskeletal conditions in the maxillofacial area. Although strong relationships between TMDs and other pain and diseases exist, few studies have comprehensively assessed the association between chronic diseases, ophthalmologic and otolaryngologic disorders and TMD.

METHODS

Of 25,534 individuals included in the fifth Korea National Health and Nutrition Examination Survey (2010-2012), 17,575 aged ≥20 years who completed survey items on TMD symptoms were included for cross-sectional analysis. Logistic regression analysis was performed to assess the association between chronic diseases, ophthalmologic and otolaryngologic disorders and examination findings, and TMD symptoms after adjusting for various confounding variables.

RESULTS

Out of 17,575 participants, 2,059 (11.75%) reported experience of ≥1 TMD symptom(s). Compared to individuals without chronic disease, those with asthma (odds ratio (OR) 1.46; 95% confidence interval (CI) 1.09-1.96), migraine (1.44; 1.26-1.65), osteoarthritis (1.51; 1.20-1.89), thyroid dysfunction (1.49; 1.13-1.96), and depressive symptoms (1.51; 1.29-1.77) had higher ORs for TMD prevalence. Participants with tinnitus (1.97; 1.70-2.27), hearing difficulties (1.55; 1.29-1.87), dizziness (1.52; 1.27-1.82), rhinitis (1.46; 1.28-1.65), and xerophthalmia (1.82; 1.57-2.12) also displayed higher ORs for TMD prevalence. Patients diagnosed with chronic rhinosinusitis upon otolaryngologic examination exhibited an OR of 1.44 (95% CI 1.11-1.87) for TMD prevalence, while that for individuals with abnormal laryngoscopic results was 0.57 (95% CI 0.36-0.90).

CONCLUSIONS

These findings imply that TMDs, chronic diseases, and ophthalmologic and otolaryngologic disorders hold various correlations, suggesting the need for multitarget approaches to effectively address this phenomenon.

Disk displacement, eccentric condylar position, osteoarthrosis - misnomers for variations of normality? Results and interpretations from an MRI study in two age cohorts

Background

Clinical decision-making and prognostic statements in individuals with manifest or suspected temporomandibular disorders (TMDs) may involve assessment of (a) the position of articular disc relative to the mandibular condyle, (b) the location of the condyle relative to the temporal joint surfaces, and (c) the depth of the glenoid fossa of the temporomandibular joints (TMJs). The aim of this study was twofold: (1) Determination of the prevalence of these variables in two representative population-based birth cohorts. (2) Reinterpretation of the clinical significance of the findings.

Methods

From existing magnetic resonance imaging (MRI) scans of the TMJs that had been taken in 2005 and 2006 from 72 subjects born between 1930 and 1932 and between 1950 and 1952, respectively, the condylar position at closed jaw was calculated as percentage displacement of the condyle from absolute centricity. By using the criteria introduced by Orsini et al. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 86:489-97, 1998), a textbook-like disc position at closed jaw was distinguished from an anterior location. TMJ morphology of the temporal joint surfaces was assessed at open jaw by measuring the depth of the glenoid fossa, using the method proposed by Muto et al. (J Oral Maxillofac Surg 52:1269-72, 1994).

Frequency distributions were recorded for the condylar and disc positions at closed jaw.

Student’s t-test with independent samples was used as test of significance to detect differences of condylar positions between the age cohorts (1930 vs. 1950) and the sexes. The significance levels were set at 5%. First, the results from the measurement of the age cohorts were compared without differentiation of sexes, i.e., age cohort 1930–1932 versus age cohort 1950–1952. Subsequently, the age cohorts were compared by sex, i.e., men in cohort 1930–1932 versus men in cohort 1950–1952, and women in cohort 1930–1932 women men in cohort 1950–1952.

Results

In both cohorts, condylar position was characterized by great variability. About 50% of the condyles were located centrically, while the other half was either in an anterior or in a posterior position. In both female cohorts, a posterior position predominated, whereas a centric position prevailed among men. Around 75% of the discs were positioned textbook-like, while the remaining forth was located anteriorly. Age had no statistically significant influence on condylar or on disc position. Conversely, comparison between the age groups revealed a statistically significant decrease of the depth of the glenoid fossa in both older cohorts. This age-dependent changes may be interpreted as flattening of the temporal joint surfaces.

Conclusions

We call for a re-interpretation of imaging findings because they may insinuate pathology which usually is not present. Instead, anterior or posterior positions of the mandibular condyle as well as an anterior location of the articular disc should be construed as a variation of normalcy. Likewise, flattening of articular surfaces of the TMJs may be considered as normal adaptive responses to increased loading, rather than pathological degenerative changes.

Trial registration

Not applicable.