Onset Of Temporomandibular Disorders Research Articles

Correlação entre sinais e sintomas da Disfunção Temporomandibular (DTM) e severidade da má oclusão

Introdução O papel da oclusão como fator etiológico das disfunções temporomandibulares (DTMs) tem sido um assunto polêmico e ainda controverso. Objetivo Avaliar a correlação entre sinais e sintomas da disfunção temporomandibular e a severidade da má oclusão. Método Foram avaliados 135 estudantes de Odontologia da UFPB. A presença de DTM foi estimada através do Índice Anamnésico de Fonseca (DMF) e de questões objetivas sobre seus sintomas. Os estudantes também foram submetidos a um protocolo resumido de avaliação clínica de DTM. A avaliação dos fatores oclusais foi realizada através do Índice de Prioridade de Tratamento (IPT) aplicado a modelos de gesso dos arcos dentários superior e inferior. As diferenças entre as médias do IPT relacionadas aos sinais e sintomas de DTM foram determinadas por meio dos testes t e One-way ANOVA. As correlações entre os fatores oclusais e a DTM foram determinadas a partir de correlação de Pearson. Resultado A severidade da má oclusão, segundo o IPT, não influenciou no surgimento de DTM e de sinais clínicos musculares ou articulares, e na necessidade de tratamento. A má oclusão de classe II, trespasse vertical acentuado e dentes girados foram estatisticamente correlacionados à necessidade de tratamento e aos sinais clínicos de DTM. Conclusão Em modelos multifatoriais, como na fisiopatologia da DTM, a oclusão pode desempenhar um papel de cofator na predisposição ou perpetuar as diferentes formas de DTM, não devendo ser considerada fator principal.

Genetic Variants Associated With Development of TMD and Its Intermediate Phenotypes: The Genetic Architecture of TMD in the OPPERA Prospective Cohort Study

Genetic risk factors are believed to combine with environmental exposures and contribute to the risk of developing temporomandibular disorder (TMD). In this prospective cohort study, 2,737 people without TMD were assessed for common genetic variation in 358 genes known to contribute to nociceptive pathways, inflammation, and affective distress. During a median follow-up period of 2.8 years, 260 people developed first-onset TMD. Hazard ratios were computed as measures of association between 2,924 single-nucleotide polymorphisms and TMD incidence. After correction for multiple testing, no single single-nucleotide polymorphism was significantly associated with risk of onset TMD. However, several single-nucleotide polymorphisms exceeded Bonferroni correction for multiple comparison or false discovery rate thresholds (.05, .1, or .2) for association with intermediate phenotypes shown to be predictive of TMD onset. Nonspecific orofacial symptoms were associated with voltage-gated sodium channel, type I, alpha subunit (SCN1A, rs6432860, P = 2.77 × 10−5) and angiotensin I–converting enzyme 2 (ACE2, rs1514280, P = 4.86 × 10−5); global psychological symptoms with prostaglandin-endoperoxide synthase 1 (PTGS1, rs3842803, P = 2.79 × 10−6); stress and negative affectivity with amyloid-β (A4) precursor protein (APP, rs466448, P = 4.29 × 10−5); and heat pain temporal summation with multiple PDZ domain protein (MPDZ, rs10809907, P = 3.05 × 10−5). The use of intermediate phenotypes for complex pain diseases revealed new genetic pathways influencing risk of TMD. PerspectiveThis article reports the findings of a large candidate gene association study of first-onset TMD and related intermediate phenotypes in the OPPERA Study. Although no genetic markers predicted TMD onset, several genetic risk factors for clinical, psychological, and sensory phenotypes associated with TMD onset were observed.

Psychological Factors Associated With Development of TMD: The OPPERA Prospective Cohort Study

Case-control studies have consistently associated psychological factors with chronic pain in general and with temporomandibular disorder (TMD) specifically. However, only a handful of prospective studies have explored whether preexisting psychological characteristics represent risk factors for first-onset TMD. The current findings derive from the prospective cohort study of the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) cooperative agreement. For this study, 3,263 TMD-free participants completed a battery of psychological instruments assessing general psychological adjustment and personality, affective distress, psychosocial stress, somatic symptoms, and pain coping and catastrophizing. Study participants were then followed prospectively for an average of 2.8 years to ascertain cases of first-onset of TMD, and 2,737 provided follow-up data and were considered in the analyses of TMD onset. In bivariate and demographically adjusted analyses, several psychological variables predicted increased risk of first-onset TMD, including reported somatic symptoms, psychosocial stress, and affective distress. Principal component analysis of 26 psychological scores was used to identify latent constructs, revealing 4 components: stress and negative affectivity, global psychological and somatic symptoms, passive pain coping, and active pain coping. In multivariable analyses, global psychological and somatic symptoms emerged as the most robust risk factor for incident TMD. These findings provide evidence that measures of psychological functioning can predict first onset of TMD. Future analyses in the OPPERA cohort will determine whether these psychological factors interact with other variables to increase risk for TMD onset and persistence. PerspectiveThis article reports that several premorbid psychological variables predict first-onset TMD in the OPPERA study, a large prospective cohort study designed to discover causal determinants of TMD pain. Measures of somatic symptoms were most strongly associated with TMD onset, but perceived stress, previous life events, and negative affect also predicted TMD incidence.

Assessment of cervical spine postural disorders in patients with temporomandibular dysfunction: a radiographic evaluation

This study aimed to assess the impact of abnormal head and neck posture on development of temporomandibular disorders (TMD) and to evaluate the possible correlation between cervical spine postural disorders and TMD by measuring craniocervical angles and distances in cervical spine radiographs of individuals with and without symptoms of temporomandibular joint dysfunction. Forty-six subjects aged 20–50 years were selected from the outpatient department of M.S. Ramaiah Dental College and divided into TMD and control groups with 23 subjects per group. The patients were subjected to clinical and radiographic evaluations. TMD diagnosis was based on clinical criteria in the Research Diagnostic Criteria for TMD (RDC/TMD). Radiographic evaluation comprised intraobserver and interobserver analyses of lateral cervical spine radiographs with measurements of three angles and two distances in the craniocervical region. Diagnosis of myofascial pain without limited mouth opening (n = 12) was the most frequent TMD diagnosis according to RDC/TMD. Radiographic evaluation showed that only atlas plane angle (APA) (p = 0.002) and anterior translation distance (ATD; Tz C2–C7) (p < 0.001) showed significant differences between the TMD group (APA: 20.96 ± 7.94°; ATD: 11.04 ± 5.270 mm) and control group (APA: 28.17 ± 10.395°, ATD: 5.70 ± 3.535 mm). Significant correlations were observed for the parameters between the observers (p < 0.05). The present results suggest that head and body posture could be related to the initial onset, development, and perpetuation of TMD and that TMD patients have a tendency to exhibit cervical spine hyperlordosis.

Are Occlusal Characteristics, Headache, Parafunctional Habits and Clicking Sounds Associated with the Signs and Symptoms of Temporomandibular Disorder in Adolescents?

[Purpose] To assess the association between the oclusal characteristics, headache, parafunctional habits and clicking sounds and signs/symptoms of TMD in adolescents. [Subjects] Adolescents between 14 and 18 years of age. [Methods] The participants were evaluated using the Helkimo Index and a clinical examination to track clicking sounds, parafunctional habits and other signs/symptoms of temporomandibular disorder (TMD). Subjects were classified according to the presence or absence of headache, type of occlusion, facial pattern and type of bite. In statistical analyse we used the chi-square test and Fisher's exact test, with a level of significance of 5%. [Results] The sample was made up of 81 adolescents with a mean age of 15.64 years; 51.9% were male. The prevalence of signals/symptoms of TMD was 74.1%, predominantly affecting females. Signals/symptoms of TMD were significantly associated with clicking sounds, headache and nail biting. No associations were found between signals/symptoms of TMD and angle classification, type of bite and facial pattern. [Conclusion] Headache is one of the most closely associated symptoms of TMD. Clicking sounds were found in the majority of cases. Therefore, the sum of two or more factors may be necessary for the onset and perpetuation of TMD.

Summary of Findings from the OPPERA Baseline Case-Control Study: Implications and Future Directions

The articles in this Compendium present first findings from the baseline case-control study of the OPPERA Program, a series of studies designed to identify risk factors for onset and persistence of painful Temporomandibular Disorders (TMD). This first series of manuscripts represents precursors to the ultimate goal of the OPPERA Program study, which is to build and then test a multivariable model designed to identify causal determinants of new onset TMD, as well as its chronicity. Embedded in OPPERA’s baseline phase was a case-control study of chronic TMD, which collected extensive phenotypic and genotypic data from individuals with examiner-classified TMD arthralgia, myalgia, or both (“TMD cases”) and people who were found not to have TMD when examined (“controls”). The heuristic model guiding the OPPERA study hypothesizes that development and clinical manifestation of TMD is driven by two global intermediate phenotypes, psychological distress and pain amplification, which in turn are influenced by both genetic factors and environmental exposures.6 To address the model’s hypotheses, phenotypic data were collected across multiple domains, including socio-demographic, clinical, psychosocial, pain sensitivity, and autonomic function. Genetic data were also obtained in order to identify potential biological pathways underlying these intermediate phenotypes and thereby contributing causally to the development of TMD. After an overview, which provides the background and conceptual foundation for OPPERA, each of the subsequent articles reports associations between a particular phenotypic domain and TMD while the final article presents genetic associations with TMD. Rather than attempting a comprehensive analysis of this rich and complex dataset, the purpose of this first series of publications is to present the OPPERA data collection methods and to provide descriptive findings from this baseline phase. Future manuscripts will directly address the primary and secondary hypotheses of the OPPERA program. Consistent with the epidemiological approach to case-control studies, this series of papers reports odds ratios as measures of the degree of association between putative risk factors and TMD.10 For the numerous risk factors measured as continuous variables, such as psychological scales, standardized odds ratios were computed, representing the change in odds of TMD associated with an increase of one standard deviation of the continuous variable. The term “risk factor” is used broadly to represent variables (both etiologic events and characteristics) present prior to onset of TMD as well as those that occur during or after onset to exacerbate the symptoms of TMD. The variables of interest range from external causes of tissue damage to psychological and physiological processes affecting pain perception. Also included are commonly-occurring genetic variants that regulate biological pathways influencing those processes. Thus, across all manuscripts, the term “risk factor” conveys association and is not intended to imply causal influence or even temporal sequence. Below, we briefly summarize and integrate the major findings from each article and discuss future plans to elucidate factors underlying the development of TMD within the OPPERA Program.

Oral and Maxillofacial Surgery and Chronic Painful Temporomandibular Disorders—A Systematic Review

To provide a systematic review of the best available research literature investigating the relation of oral and maxillofacial surgical procedures to the onset or relief of chronic painful temporomandibular disorder (TMD). A comprehensive review of the databases CINAHL, Cochrane Library, Embase, Medline, NHS Evidence--Oral Health, PsycINFO, Web of Knowledge, and MetaLib was undertaken by 2 authors (P.S., M.H.) up to June 2009 using search terms appropriate to establishing a relation between orofacial surgical procedures and TMD. The search was restricted to English-language publications. Of the 1,777 titles reviewed, 35 articles were critically appraised but only 32 articles were considered eligible. These were observational studies that fell into 2 groups; 9 were seeking to establish a surgical cause for TMD. Of these, only 2 of a series of 3 claimed that there was a significant link, but this claim was based on weak data (health insurance records) and was abandoned in a subsequent report. Twenty-three studies were seeking to achieve relief by orthognathic surgical intervention. These were also negative overall, with 7 articles showing varying degrees of mostly nonsignificant improvement, whereas 16 showed no change or a worse outcome. No published report on the putative effect of implant insertion was found. These apparently contradictory approaches underline a belief that oral surgical trauma or gross malocclusion has a causative role in the onset of TMD. However, there was no overall evidence of a surgical causal etiology or orthognathic therapeutic value. This review emphasizes that it is in the patients' best interest to carry out prospective appropriately controlled randomized trials to clarify the situation.

Editor's Summary and Q&A: Twenty-year cohort study of health gain from orthodontic treatment: Temporomandibular disorders

Introduction Temporomandibular disorder (TMD) is a common condition. Studies of TMD in relation to orthodontic treatment did not show an association, but longitudinal studies from adolescence to adulthood are lacking. The aim of this study was to investigate the relationship between orthodontic treatment and TMD with a longitudinal study design. Methods This prospective cohort study was conducted in South Wales, United Kingdom. The baseline investigation was carried out in 1981 and involved children aged 11 to 12 years (n = 1018). Follow-up investigations were done in 1984 (n = 792), 1989 (n = 456), and 2000 (n = 337). Results Overall TMD prevalence increased from the baseline (3.2%) to age 19 to 20 (17.6%) and decreased by age 30 to 31 (9.9%). TMD prevalence was higher in females at all follow-up points, except the baseline. Overall, incidences of TMD were 11.9%, 11.5%, and 6.0% at the first, second, and last follow-ups, respectively. Females were more likely to develop TMD than males (hazard ratio [HR], 2.1; 95% CI, 1.3 and 3.3), and those with high self-esteem were less likely to develop TMD (HR, 0.6; 95% CI, 0.4 and 0.8). There was no association between orthodontic treatment and new TMD onset. The incidences of persistent TMD were 20.0%, 34.9%, and 28.0% at the first, second, and last follow-ups, respectively. Females were more likely to have persistent TMD than males (HR, 2.5; 95% CI, 1.0 and 6.1). There was no association between orthodontic treatment and persistent TMD. The only significant predictors of TMD in adults aged 30 to 31 were female sex (odd ratio, 3.0; 95% CI, 1.1 and 8.2) and TMD in adolescence (odds ratio, 4.5; 95% CI, 2.0 and 10.0). Conclusions Orthodontic treatment neither causes nor prevents TMD. Female sex and TMD in adolescence were the only predictors of TMD in young adulthood. Temporomandibular disorder (TMD) is a common condition. Studies of TMD in relation to orthodontic treatment did not show an association, but longitudinal studies from adolescence to adulthood are lacking. The aim of this study was to investigate the relationship between orthodontic treatment and TMD with a longitudinal study design. This prospective cohort study was conducted in South Wales, United Kingdom. The baseline investigation was carried out in 1981 and involved children aged 11 to 12 years (n = 1018). Follow-up investigations were done in 1984 (n = 792), 1989 (n = 456), and 2000 (n = 337). Overall TMD prevalence increased from the baseline (3.2%) to age 19 to 20 (17.6%) and decreased by age 30 to 31 (9.9%). TMD prevalence was higher in females at all follow-up points, except the baseline. Overall, incidences of TMD were 11.9%, 11.5%, and 6.0% at the first, second, and last follow-ups, respectively. Females were more likely to develop TMD than males (hazard ratio [HR], 2.1; 95% CI, 1.3 and 3.3), and those with high self-esteem were less likely to develop TMD (HR, 0.6; 95% CI, 0.4 and 0.8). There was no association between orthodontic treatment and new TMD onset. The incidences of persistent TMD were 20.0%, 34.9%, and 28.0% at the first, second, and last follow-ups, respectively. Females were more likely to have persistent TMD than males (HR, 2.5; 95% CI, 1.0 and 6.1). There was no association between orthodontic treatment and persistent TMD. The only significant predictors of TMD in adults aged 30 to 31 were female sex (odd ratio, 3.0; 95% CI, 1.1 and 8.2) and TMD in adolescence (odds ratio, 4.5; 95% CI, 2.0 and 10.0). Orthodontic treatment neither causes nor prevents TMD. Female sex and TMD in adolescence were the only predictors of TMD in young adulthood.

Twenty-year cohort study of health gain from orthodontic treatment: Temporomandibular disorders

Temporomandibular disorder (TMD) is a common condition. Studies of TMD in relation to orthodontic treatment did not show an association, but longitudinal studies from adolescence to adulthood are lacking. The aim of this study was to investigate the relationship between orthodontic treatment and TMD with a longitudinal study design. This prospective cohort study was conducted in South Wales, United Kingdom. The baseline investigation was carried out in 1981 and involved children aged 11 to 12 years (n = 1018). Follow-up investigations were done in 1984 (n = 792), 1989 (n = 456), and 2000 (n = 337). Overall TMD prevalence increased from the baseline (3.2%) to age 19 to 20 (17.6%) and decreased by age 30 to 31 (9.9%). TMD prevalence was higher in females at all follow-up points, except the baseline. Overall, incidences of TMD were 11.9%, 11.5%, and 6.0% at the first, second, and last follow-ups, respectively. Females were more likely to develop TMD than males (hazard ratio [HR], 2.1; 95% CI, 1.3 and 3.3), and those with high self-esteem were less likely to develop TMD (HR, 0.6; 95% CI, 0.4 and 0.8). There was no association between orthodontic treatment and new TMD onset. The incidences of persistent TMD were 20.0%, 34.9%, and 28.0% at the first, second, and last follow-ups, respectively. Females were more likely to have persistent TMD than males (HR, 2.5; 95% CI, 1.0 and 6.1). There was no association between orthodontic treatment and persistent TMD. The only significant predictors of TMD in adults aged 30 to 31 were female sex (odd ratio, 3.0; 95% CI, 1.1 and 8.2) and TMD in adolescence (odds ratio, 4.5; 95% CI, 2.0 and 10.0). Orthodontic treatment neither causes nor prevents TMD. Female sex and TMD in adolescence were the only predictors of TMD in young adulthood.

The role of occlusal factor in the etiology of temporomandibular dysfunction

The influence of occlusal condition at the onset of temporomandibular disorders (TMD) has been strongly debated for many years and still is the source of controversy. Up to the eighties in the last century, the occlusal factors such as the presence of uncured malocclusions, discrepancies between intercuspal position and retruded contact position greater than two millimeters, retrusive and nonworking side interferences and loss of posterior teeth were considered to be the primary causes of TMD. The aim of this study was to estimate the role of occlusal factor in the etiology of craniomandibular dysfunction and therapeutic effects of irreversible occlusal therapy (occlusal equilibration) in patients with TMD. In the investigation we studied a group of 200 men and women. The average age of the selected patients was between 18 and 25 years. The purpose of TMD signs and symptoms was confirmed in every patient using a special functional analysis and evaluating the craniomandibular index (CMI) according to Fricton and Schiffman. The value of craniomandibular index was determined in the group of 15 patients with signs and symptoms of temporomandibular dysfunction. In the study groups occlusal equilibration (selective grinding) was performed according to Okeson using the central position of the mandible as the referent position in the occlusal therapy. The value of CMI was determined before and 30 days after occlusal equilibration. The results of this study confirmed the significant reduction in the signs and symptoms of TMD after occlusal equilibration. The statistical elaboration of the differences between the values of CMI I (before treatment) and CMI II (30 days after treatment) revealed highly significant differences. The CMI I values in the group ranged between 0.076 and 0.346 with the mean value of 0.188 +/- 0.082.The values of CMI II ranged between 0.038 and 0.19 with the mean value of 0.038 +/- 0.053. The study conformed the validity of irreversible occlusal therapy (selective grinding) in patients with TMD.

Orthodontic Treatment, Genetic Factors, and Risk of Temporomandibular Disorder

Traditionally, four groups of factors have been identified in the etiology of temporomandibular disorder (TMD): anatomical variation in the masticatory system; psychosocial characteristics; pain in other body regions; and demographics. Orthodontic treatment has been variously cited both as a protective and harmful factor in TMD etiology. Recently, a search has begun for a genetic influence on TMD etiology. Genetic markers can be of additional value in identifying gene-environment interactions, that is, isolating population sub-groups, defined by genotype in which environmental influences play a relatively greater or lesser etiological role. This paper reviews concepts and study design requirements for epidemiological investigations into TMD etiology. Findings are presented from a prospective cohort study of 186 females that illustrate an example of gene-environment interaction in TMD onset. Among people with a variant of the gene encoding catechol-O-methyl-transferase, an enzyme associated with pain responsiveness, risk of developing TMD was significantly greater for subjects who reported a history of orthodontic treatment compared with subjects who did not (P=0.04). While further studies are needed to investigate TMD etiology, this genetic variant potentially could help to identify patients whose risk of developing TMD is heightened following orthodontic treatment, hence serving as a risk marker useful in planning orthodontic care.

The relationship of occlusal disharmonies and symptoms of temporomandibular disorders

The influence of occlusal condition on the onset of temporomandibular disorder (TMD) has been strongly debated for many years and is still the source of controversy. Until 1980s, the occlusal factors such as the presence of uncured malocclusions, discrepancies between intercuspal position (ICP) and retruded contact position (RCP) greater than two millimeters, occlusal abnormality, particularly mediotrusion and retrusion, and loss of posterior teeth were considered the primary causes ofTMD. The objective of our study was to find correlation of occlusion disharmonies (difference between ICP and RCP) and present sings and symptoms of TMD. The study involved 60 subjects between 18 and 26 years of age who were divided in two groups. The study group consisted of 30 subjects between 18 and 26 years of age with sings and symptoms of temporomandibular disorders (TMD). TMD was confirmed according to Helkimo index. An average value of Helkimo index in this group was 1. The control group included 30 subjects between 20 and 25 years of age without TMD sings and symptoms. An average value of Helkimo index in this group was 0. The function analysis of cinematic centers position in RCP and ICP was performed in each subject using the computer pantograph Arcus-Digma (KaVo EWL GmbH, Leutkirch, Germany). The results of our study showed that the translation tracing of cinematic points from RCP to ICP was significantly different in TMD subjects and asymptomatic group (p > 0.16). In addition, the study revealed that 53.4% of subjects with sings and symptoms of temporomandibular disorders had marked translation in the lower temporomandibular joint (0.61-1.2 mm) what directed to intracapsular disorders. The results of our study suggested significant difference of RCP and ICP between subjects with sings and symptoms of the temporomandibular disorders and subjects without sings and symptoms.