Serum cortisol level and disc displacement disorders of the temporomandibular joint

Temporomandibular disorders (TMD) are a significant public health problem, affecting approximately 5–12% of the population. Objectives: This retrospective cross‐sectional study investigated the relationship between 8 AM serum cortisol levels (8ASC) and disc displacement disorders (DDD) of TMD. One hundred and forty patients with DDD were recruited. Among them, 60 patients comprised the case group of disc displacement without reduction with limited opening (DDWORWLO, age 37·7 ± 17·22), and 80 were ‘other DDD’ for the control group (age 36·4 ± 13·08). The independent variables included domains of demography, history, malocclusion, comorbid symptoms, comorbid TMD and 8ASC. Data were analysed with the chi‐square test, logistic regression and receiver operating characteristic (ROC) curve. Results of multiple logistic regression showed that 8ASC was the only factor significantly related to DDWORWLO (P = 0·006). Receiver operating characteristic analysis of DDWORWLO and 8ASC indicated an area under the curve of 0·669, standard error of 0·049 and P value of 0·001. The adequate cut‐off point of 8ASC was 12·45 (μg dL^?1), with sensitivity of 0·636, and specificity of 0·729. 8 AM serum cortisol level can be used as a clinical clue to differentiate DDWORWLO from other DDD.     

The incidence of osteoarthritic change on computed tomography of Korean temporomandibular disorder patients diagnosed by RDC/TMD; a retrospective study

Objective Osteoarthritis (OA) of the temporomandibular joint (TMJ) is generally thought to be an age-related disease like those of other joints. This study aims to investigate the incidence of computed tomographic (CT) OA changes in Korean temporomandibular disorder (TMD) patients diagnosed by the Research Diagnostic Criteria for TMD (RDC/TMD). Materials and methods The clinical records and radiographs of 1038 TMD patients (297 men and 741 women with mean age 31.1?±?17.4 and 34.0?±?16.2, respectively) diagnosed based on RDC/TMD Axis I in 2010 were reviewed. Results The incidence rate of OA changes in TMD patients is estimated to 27.3%, and higher in women than in men (15.5% in men and 32.0% in women) by 2.3 odds (p?p?Conclusions These results imply that the OA changes in young Korean TMD patients are as common as in the old and have no correlation with clinical pain and noise. Considered with high prevalence of TMDs known in the young population, the overall/absolute OA changes in the TMJ can be even higher in the young than in the old population, not like in other joints.     

Cytokines in healthy temporomandibular joint synovial fluid

Analysis of temporomandibular joint (TMJ) synovial fluid may elucidate the aetiology of temporomandibular disorders and arthritic conditions, as well as the inflammatory mechanisms involved. Knowledge about healthy synovial fluid is necessary to understand TMJ pathologies. We aimed to quantify the proinflammatory cytokines interleukin (IL)‐1β, IL‐2, IL‐6 and tumour necrosis factor (TNF), and the anti‐inflammatory cytokines IL‐10 and interferon (IFN)‐γ in healthy TMJ synovial fluid to serve as reference values for future studies on TMJ pathologies. Twenty healthy, young adult volunteers without temporomandibular dysfunction were included. Bilateral synovial fluid samples were obtained using the push‐pull technique with hydroxocobalamin described by Alstergren in 1999. Cytokines were quantified with Luminex multiplex assays and compared using nonparametric statistical analysis. No serious adverse effects were reported. Of 40 possible samples, 14 fulfilled the strict sampling criteria and were included in the analysis. Cytokine values (reported as medians with interquartile ranges) were as follows: TNF, 23 (13–37) pg mL^?1; IL‐2, 1·8 (0–22) pg mL^?1; and INF‐γ, 10 (0–47) pg mL^?1. IL‐1β, IL‐6 and IL‐10 were almost undetectable. In addition, TNF and INF‐γ cytokine levels correlated. We demonstrated that TNF was consistently detected and IFN‐γ and IL‐2 sporadically detected in the TMJ synovial fluid of healthy individuals using the hydroxocobalamin method and a multiplex assay. The cytokines IL‐10, IL‐1β and IL‐6 were barely detectable in this sample of healthy TMJs.     

Determination of a pressure pain threshold cut‐off value for the diagnosis of temporomandibular joint arthralgia

Temporomandibular joint (TMJ) disorders are divided by the American Academy of Orofacial Pain into five categories. The most common ones are joint pain, as arthralgia and joint disorders, as disc displacements. An important clinical presentation of arthralgia is the painful tenderness to manual palpation or decreased pressure pain threshold (PPT). The authors conducted a study to determine the appropriate PPT value to discriminate asymptomatic TMJ individuals from those with moderate to severe arthralgia. Forty‐nine individuals was evaluated and divided into groups: TMJ arthralgia, asymptomatic disc displacement and control group. Magnetic resonance images were obtained for all the groups, and algometry was performed on the TMJ lateral pole. Patients with arthralgia filled out a visual analogue scale (VAS). anova test with 1% of significance analysed the data. Specificity, sensitivity and ROC curve were also determined. Arthralgia group had significant lower PPT (mean of 1·07 kgf cm^?2) than the others. Asymptomatic disc displacement group (mean of 1·64 kgf cm^?2) has shown significant lower PPT than the control (mean of 2·35 kgf cm^?2). 89·66% of specificity and 70% of sensitivity were obtained when 1·36 kgf cm^?2 was applied to the TMJ (ROC area = 0·90). This value was considered to be the most appropriate to detected moderate to severe TMJ arthralgia. Indeed, the presence of disc displacement seems to significantly decrease PPT levels in asymptomatic subjects. The PPT value of 1·36 kgf cm^?2 can be used in the calibration procedures of the professionals involved with temporomandibular disorders and orofacial pain.     

Influence of intramuscular granisetron on experimentally induced muscle pain by acidic saline

The aim of this study was to investigate whether intramuscular administration of the 5‐HT₃ receptor antagonist granisetron reduces experimental muscle pain induced by repeated intramuscular injections of acidic saline into the masseter muscles. Twenty‐eight healthy and pain‐free volunteers, fourteen women and fourteen men participated in this randomized, double‐blind and placebo‐controlled study. After a screening examination and registration of the baseline pressure–pain threshold (PPT), the first simultaneous bilateral injections of 0·5 mL acidic saline (9 mg mL^?1, pH 3·3) into the masseter muscles were performed. Two days later, PPT and pain (VAS) were re‐assessed. The masseter muscle was then pre‐treated with 0·5 mL granisetron (Kytril^® 1 mg mL^?1 pH 5·3) on one side and control substance (isotonic saline, 9 mg mL^?1 pH 6) on the contralateral side. Two minutes thereafter a bilateral simultaneous injection of 0·5 mL acidic saline followed. The evoked pain intensity, pain duration, pain area and PPT were assessed. The volunteers returned 1 week later to re‐assess VAS and PPT. On the side pre‐treated with granisetron, the induced pain had significantly lower intensity and shorter duration (P < 0·05) compared with the side pre‐treated with control. A subgroup analysis showed that the effect of granisetron on pain duration was significant only in women (P < 0·001), while the effect on peak pain and pain area were significant in both sexes. The results showed no significant change in PPT. In conclusion, these results indicate that granisetron has a pain‐reducing effect on experimentally induced muscle pain by repeated acidic saline injection.     

Multivariate analysis of risk factors in relation to TMD symptoms

The epidemiological studies on risk factors for temporomandibular disorders (TMD) are still extremely lacking. Therefore, their aetiological significance has scarcely been documented. The aim of this study was to quantitatively investigate the relationship between hypothesized risk factors and the precipitation and perpetuation of TMD symptoms. The same 672 adults who participated in a previous study ( Matsuka et al., 1996 ) were selected for this study. All subjects had already answered a self‐administered questionnaire and the same questionnaire was sent to them 4 years after the first survey. The questionnaire failed to reach 58 subjects at the second survey. Of the remaining 614 subjects, 367 (166 males and 201 females with a mean age of 53·1 ± 14·2 years) returned the questionnaire, for a return rate of 59·8%. Information about three TMD symptoms [temporomandibular joint (TMJ) pain, limitation of mouth opening, TMJ noise] was obtained from the questionnaire, and fluctuation of these symptoms was assessed by comparing three pairs of answers between the first and second surveys. Information about 18 hypothesized risk factors for TMD (age, sex, trauma, bruxism, malocclusion, oral habit, etc.) were also obtained from the questionnaire at the first survey. To evaluate how strongly each risk factor was associated with precipitation and perpetuation of TMD symptoms, odds ratio of each risk factors for precipitating or perpetuating TMD symptoms was calculated by means of logistic regression analysis. Statistically significant risk factors for precipitating TMD symptoms were lip biting for TMJ pain (3·65) and trauma for limitation of mouth opening (3·20), and statistically significant risk factors for perpetuating TMD symptoms were female for TMJ pain (4·50) and TMJ noise (3·85) (odds ratio in parenthesis). The possible aetiological significance of these factors in TMD should be validated by future research.     

Increased phosphatidylcholine concentration in saliva reduces surface tension and improves airway patency in obstructive sleep apnoea

Surface tension may have important role for maintaining upper airway patency in patients with obstructive sleep apnoea. It has been demonstrated that elevated surface tension increases the pharyngeal pressures required to reopen the upper airway following collapse. The aim of the study was to evaluate the associations between the concentrations of endogenous surfactants in saliva with indices of upper airway patency in obstructive sleep apnoea. We studied 20 male patients with obstructive sleep apnoea (age: 60·3 ± 10·3 years; BMI: 25·9 ± 4·6 kg m^?2; AHI: 41·5 ± 18·6 events h^?1). We obtained 100‐μL samples of saliva prior to overnight polysomnographic sleep study. The surface tension was determined using the pull‐off force technique. The concentration of phosphatidylcholine (PC) was evaluated by liquid chromatography‐mass spectrometry (LC‐MS/MS). Regression analysis between apnoea, hypopnoea and apnoea/hypopnoea indices and the ratio of hypopnoea time/total disordered breathing time (HT/DBT) with surface tension and PC were performed. P < 0·05 was considered significant. The mean saliva surface tension was 48·8 ± 8·0 mN m^?1 and PC concentration was 15·7 ± 11·1 nM. The surface tension was negatively correlated with the PC concentration (r = ?0·48, P = 0·03). There was a significant positive correlation between surface tension with hypopnoea index (r = 0·50, P = 0·03) and HT/DBT (r = 0·6, P = 0·006), but not apnoea or apnoea/hypopnoea index (P > 0·11). Similarly, PC concentration negatively correlated with hypopnoea index (r = ?0·45, P = 0·04) and HT/DBT (r = ?0·6, P = 0·004), but not with apnoea index or AHI (P > 0·08). An increase in salivary PC concentration may increase upper airway patency in obstructive sleep apnoea through a reduction in surface tension.     

Effect of hypnosis on oral function and psychological factors in temporomandibular disorders patients

Summary This study investigated the effect of hypnosis in patients with temporomandibular disorders (TMD) with focus on oral function and psychological outcomes. Forty women (mean age ± s.d.: 38·6 ± 10·8 years) suffering from TMD (mean duration 11·9 ± 9·9 years) were randomized to four individual 1‐hour sessions of either hypnotic intervention or a control condition of simple relaxation. Pain intensity was assessed three times daily on a 0–10 Numerical Rating Scale. Additional outcomes were TMD‐associated symptoms assessed by the Research Diagnostic Criteria examination form and questionnaire, psychological symptoms (Symptom Check List 60), pain coping strategies (Coping Strategies Questionnaire), sleep difficulties (Pittsburgh Sleep Quality Index) and use of analgesics. Data were analyzed with between‐groups within‐subjects anova s. The hypnosis group significantly reduced the daily NRS pain scores from 4·5 ± 2·1 at baseline to 2·9 ± 2·4 after treatment (P < 0·001) compared to the control group where no significant changes were found (4·2 ± 1·4 to 3·9 ± 1·5) (P = 0·733). Number needed to treat for a 50% pain reduction was 4·0. The hypnosis group also increased use of the coping strategy ‘reinterpreting pain sensations’ from 5·2 ± 6·9 to 10·3 ± 6·8 (P < 0·001). Both groups exhibited significant reductions in the number of painful muscle palpation sites and pain on palpation (P < 0·004), in number of awakenings due to pain (P < 0·006), and in somatization, obsessive compulsive symptoms and anxiety (P < 0·004). Hypnosis thus appears to effectively reduce some aspects of complex TMD pain.     

Effects of oral care with tongue cleaning on coughing ability in geriatric care facilities: a randomised controlled trial

Methods for preventing aspiration pneumonia are needed soon in order to reduce mortality from aspiration pneumonia and promote the health of the elderly. The aim of this randomised controlled trial was to examine whether oral care with tongue cleaning improves coughing ability in elderly individuals living in geriatric care facilities. Participants comprised of 114 residents of 11 group homes and private nursing homes in Aso City in Kumamoto Prefecture. Participants were randomly assigned to either (i) a group that underwent routine oral care with tongue cleaning (intervention group; n = 58) or (ii) a group that underwent routine oral care alone (control group; n = 56). Coughing ability was evaluated by measuring peak expiratory flow (PEF) before and after 4 weeks of intervention. Before the intervention, PEF did not differ significantly between the intervention group (1·65 ± 1·11 L s^?1) and control group (1·59 ± 1·05 L s^?1; P = 0·658). However, on termination of the intervention, PEF was significantly higher in the intervention group (2·54 ± 1·42 L s^?1) than in the control group (1·90 ± 1·20 L s^?1; P = 0·014). After the intervention, PEF had increased significantly in both groups; however, this increase was significantly greater in the intervention group (0·90 ± 0·95 L s^?1) than in the control group (0·31 ± 0·99 L s^?1; P < 0·001). Oral care with tongue cleaning led to increased PEF, suggesting improved coughing ability. Oral care incorporating tongue cleaning appears to be important for preventing aspiration pneumonia.     

Headache attributed to masticatory myofascial pain: impact on facial pain and pressure pain threshold

There is no clear evidence on how a headache attributed to temporomandibular disorder (TMD) can hinder the improvement of facial pain and masticatory muscle pain. The aim of this study was to measure the impact of a TMD‐attributed headache on masticatory myofascial (MMF) pain management. The sample was comprised of adults with MMF pain measured according to the revised research diagnostic criteria for temporomandibular disorders (RDC/TMD) and additionally diagnosed with (Group 1, n = 17) or without (Group 2, n = 20) a TMD‐attributed headache. Both groups received instructions on how to implement behavioural changes and use a stabilisation appliance for 5 months. The reported facial pain intensity (visual analogue scale – VAS) and pressure pain threshold (PPT – kgf cm^?2) of the anterior temporalis, masseter and right forearm were measured at three assessment time points. Two‐way anova was applied to the data, considering a 5% significance level. All groups had a reduction in their reported facial pain intensity (P < 0·001). Mean and standard deviation (SD) PPT values, from 1·33 (0·54) to 1·96 (1·06) kgf cm^?2 for the anterior temporalis in Group 1 (P = 0·016), and from 1·27 (0·35) to 1·72 (0·60) kgf cm^?2 for the masseter in Group 2 (P = 0·013), had significant improvement considering baseline versus the 5th‐month assessment. However, no differences between the groups were found (P > 0·100). A TMD‐attributed headache in patients with MMF pain does not negatively impact pain management, but does change the pattern for muscle pain improvement.     

Ricinus communis treatment of denture stomatitis in institutionalised elderly

This study compared the effectiveness of Ricinus communis (RC) with Nystatin (NYS) and Miconazole (MIC) in the treatment of institutionalised elderly with denture stomatitis (DS). They (n = 30) were randomly distributed into three groups: MIC, NYS or RC. Clinical and mycological evaluations were performed prior to the use of the antifungal (baseline) and repeated after 15 and 30 days of treatment. The sample was clinically examined for oral mucosal conditions. Standard photographs were taken of the palate, and the oral candidiasis was classified (Newton's criteria). Mycological investigation was performed by swabbing the palatal mucosa, and Candida spp. were quantified by counting the number of colony‐forming units (cfu mL^?1). The clinical and mycological data were analysed, respectively by Wilcoxon and Student's t‐test (α = 0·05). Significant improvement in the clinical appearance of DS in the MIC and RC groups was observed between the 1st and 3rd collections (MIC – P = 0·018; RC – P = 0·011) as well as between the 2nd and 3rd collections (MIC – P = 0·018; RC – P = 0·011). Neither groups showed a statistically significant reduction in cfu mL^?1 at any time. Although none of the treatments decreased the cfu mL^?1, it was concluded that Ricinus communis can improve the clinical condition of denture stomatitis in institutionalised elderly patients, showing similar results to Miconazole.     

Clinical phenotype of South–East Asian temporomandibular disorder patients with upper airway resistance syndrome

Clinical and radiographic characteristics of a subset of South East Asian temporomandibular disorder (TMD) patients with comorbid upper airway resistance syndrome (UARS) were documented in a multi‐center prospective series of 86 patients (26 men and 60 women / mean age 35.7 years). All had excessive daytime sleepiness, high arousal index and Apnoea‐Hypopnoea Index (AHI) <5. The mean body mass index was 20·1, mean arousal index 16·2, mean respiratory disturbance index 19·6, mean AHI 3·9 while the mean Epworth Sleepiness Scale was 14·8. Many had functional somatic complaints; 66·3% headaches, 41·9% neck aches, 53·5% masticatory muscle myalgia, 68·6% temporomandibular joint (TMJ) arthralgia while 90·7% reported sleep bruxism (SB). Unlike patients with obstructive sleep apnoea (OSA), hypertension was uncommon (4·7%) while depression was prevalent at 68·6% with short REM latency of <90 min and an increased REM composition >25% documented in 79·6% and 57·6% of these depressed patients, respectively. 65·1% displayed a posteriorly displaced condyle at maximum intercuspation with or without TMJ clicking. Most exhibited a forward head posture (FHP) characterised by loss of normal cervical lordosis (80·2%), C0–C1 narrowing (38·4%) or an elevated hyoid position (50%), and 91·9% had nasal congestion. We postulate the TMD‐UARS phenotype may have originally developed as an adaptive response to ‘awake’ disordered breathing during growth. Patients with persistent TMD and/or reporting SB should be screened for UARS and chronic nasal obstruction, especially when they also present with FHP. The lateral cephalogram is a useful tool in the differentiation of UARS from other OSA phenotypes.     

Transcranial direct current stimulation and exercises for treatment of chronic temporomandibular disorders: a blind randomised‐controlled trial

To evaluate the effect of adding transcranial direct current stimulation (tDCS) to exercises for chronic pain, dysfunction and quality of life in subjects with temporomandibular disorders (TMD). Participants were selected based on the RDC/TMD criteria and assessed for pain intensity, pressure pain threshold over temporomandibular joint and cervical muscles and quality of life. After initial assessment, all individuals underwent a 4‐week protocol of exercises and manual therapy, together with active or sham primary motor cortex tDCS. Stimulation was delivered through sponge electrodes, with 2 mA amplitude, for 20 min daily, over the first 5 days of the trial. A total of 32 subjects (mean age 24·7 ± 6·8 years) participated in the evaluations and treatment protocol. Mean pain intensity pre‐treatment was 5·5 ± 1·4 for active tDCS group, and 6·3 ± 1·2 for sham tDCS. Both groups showed a decrease in pain intensity scores during the trial period (time factor – F_4·5,137·5 = 28·7, P < 0·001; group factor – F_1·0,30·0 = 7·7, P < 0·05). However, there were no differences between the groups regarding change in pain intensity (time*group interaction – F_4·5,137·5 = 1·5, P = 0·137). This result remained the same after 5 months (t‐test t = 0·29, P > 0·05). Pressure pain thresholds decrease and improvement in quality of life were also noticeable in both groups, but again without significant differences between them. Absolute benefit increase was 37·5% (CI 95%: ?15·9% to 90·9%), and number needed to treat was 2·66. This study suggests that there is no additional benefit in adding tDCS to exercises for the treatment of chronic TMD in young adults.     

The prevalence of temporomandibular disorder signs in people with mental retardation

Summary The purpose of this study was to determine the prevalence of temporomandibular disorder (TMD) signs and tooth wear levels in a group of hospitalised patients with mental retardation (MR). A total of 118 patients with MR and 104 mentally healthy individuals (control) were included in this study. The groups consisted of equal numbers of male and female patients. TMD signs were evaluated according to the Research Diagnostic Criteria to assess the limitation in maximum mouth opening, the alterations in the mouth opening pathway and temporomandibular joint sounds. In addition, tooth wear was recorded. The frequency of at least one sign of TMD observed in patients with MR (79·7%) was significantly higher than in controls (69·2%) (P = 0.03). In addition, 43.2% of the patients with MR had more than one sign of TMD compared with 28.8% of the control group (P = 0·02). Prevalence of each sign exhibited in the MR and control groups was as follows: limitation in mouth opening, 24·6% vs. 13·5% (P = 0·02); deviation, 18·6% vs. 26·9% (P = 0·001); deflection, 29·7% vs. 10·6% (P = 0·001); TMJ sounds, 46·6% vs. 41·1% (P = 0·43); bilateral joint sounds 28·8% vs. 16·3% (P = 0·05) respectively. Prevalences of TMD signs were not different between genders in both groups (P > 0·05). Severe tooth wear was evident in 43·2% of the patients with MR compared with 20·6% of the controls (P = 0·001). In conclusion, patients with MR seem to be more prone to having TMD signs compared with the control population.     

Efficacy of low‐level laser therapy in the treatment of TMDs: a meta‐analysis of 14 randomised controlled trials

This study was designed to evaluate the efficacy of low‐level laser therapy (LLLT) in the treatment of temporomandibular disorders (TMDs). We searched electronic databases and references lists of relevant articles, retrieved all of the published randomised controlled trials in regard to these issues and then performed a meta‐analysis. Fourteen highly qualified RCTs reporting on a total of 454 patients, which evaluated the effectiveness of LLLT for patients suffering from TMDs were retrieved. The results indicated that LLLT was not better than placebo in reducing chronic TMD pain (weighted mean difference = ?19·39; 95% confidence interval = ?40·80–2·03; P < 0·00001; I² = 99%). However, the LLLT provided significant better functional outcomes in terms of maximum active vertical opening (MAVO) (weighted mean difference = 4·18; 95% confidence interval = 0·73–7·63; P = 0·006; I² = 73%), maximum passive vertical opening (MPVO) (weighted mean difference = 6·73; 95% confidence interval = 01·34–12·13; P = 0·06; I² = 73%), protrusion excursion (PE) (weighted mean difference = 1·81; 95% confidence interval = 0·79–2·83; P = 0·59; I² = 0%) and right lateral excursion (RLE) (weighted mean difference = 2·86; 95% confidence interval = 1·27–4·45; P = 0·01; I² = 73%). The results of our meta‐analysis have provided the best evidence on the efficacy of LLLT in the treatment of TMDs. This study indicates that using LLLT has limited efficacy in reducing pain in patients with TMDs. However, LLLT can significantly improve the functional outcomes of patients with TMDs.     

Obesity as a risk factor for temporomandibular disorders

We conducted a clinical cross‐sectional study to evaluate the association between obesity and the presence of painful temporomandibular disorders (TMD), controlling for age, gender, presence of migraine, depression, non‐specific somatic symptoms and obstructive sleep apnoea syndrome (OSAS) in an adult population. A total of 299 individuals (76·6% women) with a mean age of 36·8 ± 12·8 years were evaluated. TMD were classified using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Depression and non‐specific somatic symptoms were scored by the Symptom Checklist‐90, while pain and disability was rated by the Graded Chronic Pain Scale. Bioimpedanciometry (BIA) was used to assess obesity through total body fat percentage. Migraine was diagnosed according to the criteria of the International Classification of Headache Disorders‐2 (ICHD‐2). OSAS was classified according to the Berlin Questionnaire. We performed univariate and multivariate models, chi‐square tests and odds ratios (OR) with 95% confidence intervals (CI). In the single regression analysis, TMD‐pain was significantly associated with total body fat percentage (P = 0·01). In the multivariate analysis, migraine, age, non‐specific somatic symptoms and OSAS showed to be stronger predictors of TMD‐pain, and obesity did not retain in the regression model. The initial association found between obesity and TMD‐pain is lost when it was corrected for gender, migraine, non‐specific somatic symptoms and OSAS.     

Jaw clenching effects in relation to two extreme occlusal features: patterns of diagnoses in a TMD patient population

Objective:

The aim of this investigation was to compare the pattern of temporomandibular disorder (TMD) diagnoses in clenching patients with different occlusal features, the null hypothesis being that no between-group differences exist.

Materials and methods:

Two groups of subjects receiving a jaw clenching diagnosis and having large overjet or anterior open bite (Group A; N?=?45, 75·5% females, mean age: 38·1±15·9 years) or normal occlusion (Group B; N?=?69, 71% females, mean age: 34·6±13·8 years) were recruited among a TMD patient population and were given Research Diagnostic Criteria for TMD (RDC/TMD) axis I diagnoses, namely, group I muscle disorders, group II disc displacements, and group III arthralgia/osteoarthritis/osteoarthrosis.

Major findings:

The distribution of RDC/TMD single and combined group diagnoses was significantly different between the two groups (P<0·05), with Group A subjects showing a higher prevalence of multiple diagnoses (60% versus 43·3%), as well as a higher prevalence of combined RDC/TMD axis I group II and III diagnoses (37·8% versus 20·2%). All TMD signs and symptoms were more frequent in the patients with large overjet or anterior open bite with respect to the patients with normal occlusion.

Conclusion:

In a TMD patient population, jaw clenching may have different consequences in subjects with large overjet or anterior open bite with respect to subjects featuring normal occlusion.     

Evaluation of minimum interdental threshold ability in dentate female temporomandibular disorder patients

Summary Minimum interdental threshold is the smallest thickness that can be detected between teeth during an occlusion and has an influence on the occlusal force and on the control of mandibular movements. The aim of this study was to assess the possible association of the signs and symptoms of temporomandibular disorders (TMD) with the ability to detect a minimum interdental threshold. Two hundred women were equally divided into four groups: asymptomatic (control), subjects with masticatory muscle pain, with articular [temporomandibular joint (TMJ)] pain and mixed (muscular and articular pain). Evaluation of the ability to detect a minimum interdental threshold was performed using aluminium foils with 0·010, 0·024, 0·030, 0·050, 0·080 and 0·094 mm of thickness in the premolar region. A total of 20 tests with each thickness for each patient were performed, starting with the thickest foil (0·094 mm) and ending with the thinnest one. The myogenic pain and articular groups presented significantly higher threshold values (0·020 and 0·022 mm, respectively), when compared to the control. Both groups reached the level of certain perceptiveness only at 0·030 mm. No significant correlation was found between minimum interdental threshold and age. These results suggest that discrimination of thicknesses can be disturbed as a consequence of TMD manifestations and not the cause of it. Clinicians should, therefore, be aware that changes on muscles and TMJ can secondarily lead to occlusion changes. The mechanisms involved in this process, however, are not well understood and warrant further investigation.     

Are occlusal features associated with different temporomandibular disorder diagnoses in bruxers?

Aims:

The present study was designed to test the hypothesis that dental occlusion may have a role in mediating the effects of bruxism in temporomandibular disorders (TMD) patients. It aimed to answer the clinical research question: in a population of TMD patients with clinically diagnosed clenching-type bruxism, are the different TMD diagnoses associated with different occlusal features?

Materials and methods:

A total of 294 TMD patients (73% females, mean age 38·3±9·2 years) who were positive for a clinical diagnosis of clenching-type bruxism underwent an assessment in accordance with the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) axis I, as well as a recording of nine occlusal features. Statistical analyses were performed to test the null hypotheses that: (1) no differences existed between the patients with or without the various occlusal features as for the prevalence of the various single and combined RDC/TMD group diagnoses (single variable analysis), and (2) having any specific occlusal feature makes no difference in distinguishing within the RDC/TMD diagnoses (multiple variable analysis).

Results:

The distribution of the different combination of RDC/TMD axis I diagnoses was significantly different in patients with laterotrusive interferences with respect to those without such interferences (chi-square?=?15·209; P?=?0·033) as well as in patients with a slide from retruded contact position (RCP) to maximum intercuspation (MI) >2 mm with respect to those without such slide (chi-square?=?4·029; P?=?0·012) and in those with or without molar class asymmetry (chi-square?=?17·438; P?=?0·015). Multinomial regression analysis showed that the model including the various occlusal features account for 20·4% of the variance for RDC/TMD diagnoses (Nagelkerke R²?=?0·204) and allowed the rejection of the null hypothesis that having such specific occlusal features makes no difference in distinguishing within the RDC/TMD diagnoses.

Conclusions:

Within the limitations of this study, it can be suggested that in a population of patients with TMD and clinically-diagnosed clenching-type bruxism, the patterns of TMD diagnoses may be influenced, at least in part, by the presence of some features of dental occlusion, namely, slide RCP-MI, laterotrusive interferences, and molar asymmetry.     

关节液中MMP-2和MMP-3含量对颞下颌关节紊乱病诊断的意义

目的:探讨关节液中基质金属蛋白酶-2(matrixmetalloproteinase-2,MMP-2)和基质金属蛋白酶-3(matrixmetalloproteinase-3,MMP-3)的表达与关节病变程度的关系。方法:留取颞下颌关节紊乱病(temporomandibularjointdisorder,TMD)患者126侧关节和健康志愿者32侧关节的关节液标本,依据临床检查和TMJ影象学检查将标本分为(1)关节炎症性疾病(capsulitis/synovitis,C/S)组(n=24);(2)结构紊乱(internalderangement,ID)组(n=58);(3)骨关节病(osteoarthritis,OA)组(n=44);(4)健康志愿者对照组(n=32)。用双抗体夹心酶联免疫法检测关节液标本中MMP-2和MMP-3的含量。结果:关节液中MMP-2含量:OA组(42.656±14.515)ng/mL,ID组(34.772±12.647)ng/mL,C/S组(29.500±8.177)ng/mL,对照组(20.927±4.830)ng/mL。关节液中MMP-3含量:OA组(74.677±46.910)ng/mL;ID组(49.086±22.298)ng/mL;C/S组(32.609±9.470)ng/mL;对照组(23.663±8.767)ng/mL。统计学检验:MMP-2和MMP-3在OA组与其余3组间比较均有显著性差异(P<0.05);ID组、C/S组与对照组间比较均有显著性差异(P<0.05);但ID组与C/S组间比较无显著差异(P>0.05)。结论:TMD患者关节液中MMP-2和MMP-3的表达水平随着关节病变程度的增加而显著升高,表明它们不仅参与了关节组织的病理破坏,而且与关节破坏程度密切相关,它们在关节液中的表达水平反映了TMD病变的严重程度。关节液中的MMP-2和MMP-3可以作为代表TMD关节损害和代谢的客观生化分子标志。