Frequency of awake bruxism behaviours in the natural environment. A 7-day, multiple-point observation of real-time report in healthy young adults.

The aim of this study was to assess awake bruxism (AB) behaviours in a sample of healthy young adults using a smartphone-based application for a real-time report (ie, ecological momentary assessment [EMA], also called experience sampling method [ESM]). Forty-six dental students used a smartphone application that sent 15 alerts at random intervals during the day for 1 week to collect AB self-reports. They had to answer on time by tapping on the display icon that refers to their current condition of jaw muscles: relaxed; teeth contact; teeth clenching; teeth grinding; jaw clenching without teeth contact (ie, bracing). The average frequency of relaxed jaw muscles, as a percentage of answers over the 7 days, was 71.7%. Teeth contact (14.5%) and jaw clenching (10.0%) were the most frequent AB behaviours. No significant gender differences were detected. Interindividual differences were quite relevant, but the overall frequency was in general only moderately variable from day-to-day. Coefficient of variation (CV) was low for the condition "relaxed jaw muscles" (0.44). At the individual level, teeth contact was the most prevalent behaviour, with a 39.1%-52.2% proportion of subjects reporting it at least once a day. During a 7-day observation period, the frequency of real-time report of AB behaviours in a sample of healthy young adults was 28.3%. The low daily variability in the average frequency value for the relaxed jaw muscles condition suggests that EMA may be a reliable strategy to get deeper into the epidemiology of oral behaviours. This investigation introduced EMA principles to the study of AB and provided data on the frequency of AB behaviours in young adults that could be compared to populations with risk/associated factors and possible clinical consequences.

Subjects with temporomandibular joint disc displacement do not feature any peculiar changes in body posture.

The presence of body posture changes among patients with temporomandibular disorders (TMD) has been a controversial topic in dentistry. Based on that, the aim of this study was to assess postural features of pain-free subjects with internal derangement of the temporomandibular joint (TMJ), viz. disc displacement, when compared to subjects with normal disc position. A total of 21 subjects with unilateral, pain-free TMJ disc displacement (DD) and 21 subjects without any TMD signs of symptoms were assessed for body posture changes by means of posturographic evaluation of several body segments and postural balance reactions through the centre of mass during jaw movements using a balance platform. Posturographic measurements showed the absence of any significant differences between the two groups in any of the outcome parameters. Similarly, all balance platform responses to mandibular movements were not different between groups. There are no significant differences in body posture between subjects with and without unilateral disc displacement in the temporomandibular joint. Such observations, indicating a well-preserved postural balance in the presence of TMJ internal derangement, put into serious question the potential influence of TMJ disorders on whole body posture and viceversa.

Single- or multiple-session viscosupplementation protocols for temporomandibular joint degenerative disorders: a randomized clinical trial.

The aim of the study was to compare the effectiveness of two single-session protocols, either adopting high- (protocol A) or medium-molecular weight hyaluronic acid (protocol B), with the reference five-session protocol of temporomandibular joint (TMJ) lavage plus viscosupplementation (protocol C) in the management of chronic TMJ degenerative disorders. A randomized clinical trial (RCT) with ten participants per treatment group was designed, with multiple observation points, ending at 6 months after treatment. Pain levels on a 10-point VAS scale were selected as the primary outcome variable to rate treatment effectiveness, along with a number of secondary outcome parameters. Findings showed that Group C patients had the highest decrease in pain levels. Nonparametric permutation analyses revealed that the global effect of treatment was significantly different between the three protocols (P = 0·024). Pairwise comparisons showed that the differences of treatment effect between the two single-session interventions were negligible (global P-value = 0·93). On the contrary, the five-session protocol was significantly superior to both single-session protocols (global P-values ranging from 0·003 to 0·012). In conclusion, in a population of age-, sex-, and psychosocial aspects-matched study groups, the standard of reference five-session protocol proved to be superior at 6 months as far as the decrease in pain levels was concerned, whilst there were no differences between the two single-session interventions. The absence of differences in treatment effect as for some other secondary clinical outcome variables may suggest that there is further space for future investigations attempting to reduce the number of multiple interventions for TMJ viscosupplementation.

Diagnostic accuracy of portable instrumental devices to measure sleep bruxism: a systematic literature review of polysomnographic studies.

This study systematically reviews the sleep bruxism (SB) literature published in the MEDLINE and Scopus databases to answer the following question: What is the validity of the different portable instrumental devices that have been proposed to measure SB if compared with polysomnographic (PSG) recordings assumed as the gold standard? Four clinical studies on humans, assessing the diagnostic accuracy of portable instrumental approaches (i.e. Bitestrip, electromyography (EMG)-telemetry recordings and Bruxoff) with respect to PSG, were included in the review. Methodological shortcomings were identified by QUADAS-2 quality assessment. Findings showed contrasting results and supported only in part the validity of the described diagnostic devices with respect to PSG. The positive predictive value (PPV) of the Bitestrip device was 59-100%, with a sensitivity of 71-84·2%, whilst EMG-telemetry recordings had an unacceptable rate of false-positive findings (76·9%), counterbalanced by an almost perfect sensitivity (98·8%). The Bruxoff device had the highest accuracy values, showing an excellent agreement with PSG for both manual (area under ROC = 0·98) and automatic scoring (0·96) options as well as for the simultaneous recording of events with respect to PSG (0·89-0·91). It can be concluded that the available information on the validity of portable instrumental diagnostic approaches with respect to PSG recordings is still scarce and not solid enough to support any non-PSG technique's employ as a stand-alone diagnostic method in the research setting, with the possible exception of the Bruxoff device that needs to be further confirmed with future investigations.

Effectiveness of treatment with viscosupplementation in temporomandibular joints with or without effusion.

The objective of this study was to determine whether the effectiveness of viscosupplementation with hyaluronic acid (HA) in patients with temporomandibular joint (TMJ) degenerative disorders depends on the presence of intra-articular effusion. In this study of case-control design, two groups of 25 patients were recruited: patients with a clinical diagnosis of painful chronic TMJ osteoarthritis and magnetic resonance imaging (MRI) signs of TMJ degeneration, with (effusion group) or without (no effusion group) MRI evidence of TMJ effusion. All patients underwent five weekly single-needle arthrocenteses plus medium molecular weight HA and 6 months of follow-up. Several clinical outcome parameters were assessed. For all variables, analysis of variance (ANOVA) for repeated measures was performed to assess the existence of significant within-group and between-group treatment effects. Over time, both groups showed significant improvements in all outcome parameters, which were maintained at the 6-month follow-up (P<0.05). Between-group comparisons showed that the treatment effects did not differ significantly for either the primary outcome variable (pain levels: F=0.849, P=0.548) or secondary outcome variables (chewing efficiency: F=0.854, P=0.544; functional limitation: F=1.35, P=0.226; mouth opening: F=0.658, P=0.707). The null hypothesis that there are no differences in treatment effectiveness between patients with and without effusion could not be rejected.

Correlation between self-reported and clinically based diagnoses of bruxism in temporomandibular disorders patients.

The present investigation was performed in a population of patients with temporomandibular disorders (TMD), and it was designed to assess the correlation between self-reported questionnaire-based bruxism diagnosis and a diagnosis based on history taking plus clinical examination. One-hundred-fifty-nine patients with TMD underwent an assessment including a questionnaire investigating five bruxism-related items (i.e. sleep grinding, sleep grinding referral by bed partner, sleep clenching, awake clenching, awake grinding) and an interview (i.e. oral history taking with specific focus on bruxism habits) plus a clinical examination to evaluate bruxism signs and symptoms. The correlation between findings of the questionnaire, viz., patients' report, and findings of the interview/oral history taking plus clinical examination, viz., clinicians' diagnosis, was assessed by means of φ coefficient. The highest correlations were achieved for the sleep grinding referral item (φ = 0·932) and for the awake clenching item (φ = 0·811), whilst lower correlation values were found for the other items (φ values ranging from 0·363 to 0·641). The percentage of disagreement between the two diagnostic approaches ranged between 1·8% and 18·2%. Within the limits of the present investigation, it can be suggested that a strong positive correlation between a self-reported and a clinically based approach to bruxism diagnosis can be achieved as for awake clenching, whilst lower levels of correlation were detected for sleep-time activities.

Natural course of temporomandibular disorders with low pain-related impairment: a 2-to-3-year follow-up study.

To describe the natural course of temporomandibular disorders (TMD) in patients with low levels of pain-related impairment, independently by the physical diagnoses they received. Amongst all patients who attended the TMD Clinic, University of Padova, Italy, during the year 2009, those who: (i) had Research Diagnostic Criteria for TMD (RDC/TMD) axis II Graded Chronic Pain Scale (GCPS) grade 0 or 1 scores, (ii) received counselling on their signs and symptoms at the time of their first visit and suggestions on how to self-manage their symptoms, (iii) did not attend the Clinic since the time of their last visit and (iv) were visited by the same resident, were recalled for a follow-up assessment during the period from September to December 2011. Sixty-nine patients (79% females; mean age 47.4 ± 11.3 years; range 26-77) of 86 who were potentially eligible accepted to enter the study. The time span since the first visit ranged from 23 to 36 months. At the follow-up assessment, the percentage of patients with muscle disorders decreased from 68.1% to 23.1%; disc displacement with reduction remained unchanged (52.1%), whilst the 5.7% of patients who had disc displacement without reduction with limited opening then showed absence of limitation; diagnoses related to other joint disorders decreased from 30.4% to 14.4% for arthralgia and from 27.5% to 24.6% for osteoarthritis/osteoarthrosis. In a sample of patients TMD with low pain-related impairment followed up with a single recall assessment at 2-to-3 years, the natural course of disease was generally favourable.

Axis II psychosocial findings predict effectiveness of TMJ hyaluronic acid injections.

The objective was to investigate the correlation between levels of depression, somatization, and pain-related impairment, as assessed by the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMDs) axis II, and the treatment outcome of a cycle of five weekly injections of hyaluronic acid immediately following arthrocentesis. 57 consecutive patients with a diagnosis of temporomandibular joint (TMJ) osteoarthritis according to the RDC/TMD underwent the treatment protocol and a follow-up assessment at 6 months. Axis II findings were assessed as potential predictors of improvement in visual analogue scale (VAS) values at the end of the observation period with respect to baseline. The percentage of VAS improvement at the end of treatment was inversely related to all the psychosocial variables. The best fitting model identified pain-related impairment (p<0.001) and disability points (p<0.001) as the most significant predictors of VAS changes. The percentage of variance in the outcome variable explained by the significant predictors was high (R(2) 70.5%). All the RDC/TMD axis II psychosocial scores (depression, somatization, and pain-related impairment levels) were inversely correlated with therapeutic outcome. The clinical relevance of these findings is important, since psychosocial diagnosis may be even more important than physical evaluation in terms of prognostic impact.

Psychometric features of temporomandibular disorders patients in relation to pain diffusion, location, intensity and duration.

The aim of the present investigation was to assess the psychological profile of a sample of patients with temporomandibular disorders (TMD) and to compare the psychometric scores between patients with pain of different diffusion, location, intensity and duration. One hundred and ten (N = 110) patients with painful TMD fulfilled three psychometric instruments. Pain features were assessed as categorical variables as concerns its diffusion, viz., diffuse or localised, duration, viz., more or <6 months, and location, viz., joint and/or muscles. Pain intensity was scored on a 0-100 Visual Analog Scale (VAS) rating. Patients with diffuse pain showed higher psychometric scores than patients with localised pain. No significant differences were detected between patients with pain lasting from more or equal than 6 months and those with pain lasting from <6 months as well as between patients with pain localised in the jaw muscles, joints or both, even if a trend for lower scores for patients with joint pain alone was observed. Pain intensity was significantly related with anxiety (ANX), depression (DEP) and somatisation(SOM) scores. In conclusion, pain diffusion and intensity were strongly related with high levels of SOM, ANX and DEP, while no differences in psychometric scores were detected between patients with pain of different duration and location.

Dental occlusion, body posture and temporomandibular disorders: where we are now and where we are heading for.

The aim of this investigation was to perform a review of the literature dealing with the issue of relationships between dental occlusion, body posture and temporomandibular disorders (TMD). A search of the available literature was performed to determine what the current evidence is regarding: (i) The physiology of the dental occlusion-body posture relationship, (ii) The relationship of these two topics with TMD and (iii) The validity of the available clinical and instrumental devices (surface electromyography, kinesiography and postural platforms) to measure the dental occlusion-body posture-TMD relationship. The available posturographic techniques and devices have not consistently found any association between body posture and dental occlusion. This outcome is most likely due to the many compensation mechanisms occurring within the neuromuscular system regulating body balance. Furthermore, the literature shows that TMD are not often related to specific occlusal conditions, and they also do not have any detectable relationships with head and body posture. The use of clinical and instrumental approaches for assessing body posture is not supported by the wide majority of the literature, mainly because of wide variations in the measurable variables of posture. In conclusion, there is no evidence for the existence of a predictable relationship between occlusal and postural features, and it is clear that the presence of TMD pain is not related with the existence of measurable occluso-postural abnormalities. Therefore, the use instruments and techniques aiming to measure purported occlusal, electromyographic, kinesiographic or posturographic abnormalities cannot be justified in the evidence-based TMD practice.

Self-reported bruxism and temporomandibular disorders: findings from two specialised centres.

The aims of this investigation were to report the frequency of temporomandibular disorders (TMD) diagnoses and the prevalence of self-reported awake and sleep bruxism as well as to describe the possible differences between findings of two specialised centres as a basis to suggest recommendations for future improvements in diagnostic homogeneity and accuracy. A standardised Research Diagnostic Criteria for TMD (RDC/TMD) assessment was performed on patients attending both TMD Clinics, viz., at the University of Padova, Italy (n=219; 74% women) and at the University of Tel Aviv, Israel (n=397; 79% women), to assign axis I physical diagnoses and to record data on self-reported awake and sleep bruxism. Significant differences were shown between the two clinic samples as for the frequency of TMD diagnoses (chi-square, P<0·001) and the prevalence of at least one positive response to bruxism items (chi-square, P<0·001). The more widespread use of TMJ imaging techniques in one clinic sample led to a higher prevalence of multiple diagnoses, and the higher prevalence of self-reported bruxism in patients with myofascial pain alone described in the other clinic sample was not replicated, suggesting that the different adoption of clinical and imaging criteria to diagnose TMD may influence also reports on their association with bruxism. From this investigation, it emerged that the features of the study samples as well as the different interpretation of the same diagnostic guidelines may have strong influence on epidemiological reports on bruxism and TMD prevalence and on the association between the two disorders.

Arthrocentesis with or without additional drugs in temporomandibular joint inflammatory-degenerative disease: comparison of six treatment protocols*.

The aim of the present pilot investigation was to compare the effectiveness of six treatment protocols providing temporomandibular joint (TMJ) arthrocentesis with or without additional drugs to manage symptoms in patients with inflammatory-degenerative TMJ disease. A consecutive series of 72 patients with TMJ osteoarthritis (axis group IIIb) with pain lasting from more than 6 months were randomly assigned to one of the groups receiving the following treatment protocols: single-session two-needle arthrocentesis (A), single-session two-needle arthrocentesis plus corticosteroid (B), single-session two-needle arthrocentesis plus low molecular weight hyaluronic acid (HA) (C), single-session two-needle arthrocentesis plus high molecular weight HA (D), 5 weekly two-needle arthrocenteses plus low molecular weight HA (E) and 5 weekly single-needle arthrocenteses plus low molecular weight HA (F). At the 3-month follow-up, improvement with respect to mean baseline values was recorded in all the five treatment groups completing the protocol. No significant differences emerged between groups in any outcome variable. The protocol providing five sessions of two-needle arthrocenteses plus low molecular weight HA allowed achieving the highest improvement in almost all the outcome variables. Findings suggested that no statistically significant differences existed between the treatment groups. The clinical significance of these findings needs to be tested with future studies on larger samples with longer follow-up periods.

Two-needle vs. single-needle technique for TMJ arthrocentesis plus hyaluronic acid injections: a comparative trial over a six-month follow up.

The aim of the study was to compare the effectiveness of five weekly two-needle arthrocentesis plus hyaluronic injections vs. the same protocol performed with a single-needle technique in patients with inflammatory-degenerative disorders of the temporomandibular joint (TMJ). 80 patients with TMJ osteoarthritis were randomly assigned to the two-needle or single-needle protocol and followed up for 6 months after treatment. Several outcome parameters, such as maximum pain at rest and maximum pain on chewing, subjective chewing efficiency, limitation in jaw function, jaw range of motion in mm, were recorded at baseline and multiple follow up assessments. Both treatment groups recorded significant improvement with respect to baseline levels in almost all outcome variables. The rate of improvement was not significantly different between the treatment protocols in any of the outcome variables (p-values between 0.143 and 0.970). No between-group differences emerged for the perceived subjective efficacy (p=0.321) and the treatment tolerability (p=0.783). The present investigation did not support the existence of significant differences in the treatment effectiveness for inflammatory-degenerative TMJ disorders of a cycle of five weekly injections of arthrocentesis plus hyaluronic acid injections performed according to the classical two-needle or the single-needle technique.

Influence of psychological symptoms on home-recorded sleep-time masticatory muscle activity in healthy subjects.

The present investigation attempts to describe the correlation between sleep-time masticatory muscle activity (MMA) and psychological symptoms by the use of a four-channel electromyography (EMG) home-recording device in a group of 15 healthy volunteers completing a battery of psychometric questionnaires for the assessment of anxiety, depression and anger. The integrated EMG signal was adopted to quantify the work (µV × s) produced by each of the four muscles (bilateral masseter and temporal) during the 5-h recording span and per each 1-h increment. The duration of MMA events and the muscle work during the first hour of sleep was related to trait anxiety scores for both masseter (P = 0·007) and temporalis muscles (P = 0·022). Trait anxiety was also significantly correlated to the total amount of MMA duration (in seconds) of the temporalis muscles (r = 0·558; P = 0·031). The present investigation provides support to the hypothesis that the duration of sleep-time masticatory muscle activity, especially during the early phases of a night's sleep, may be related to anxiety trait and not to anxiety state, depression or anger. These findings may support the view that features related to the individual management of anxiety, viz. trait, are likely to be more important than acute episodes of anxiety, viz. state, in the aetiology of sleep-time masticatory muscle activity. The role of other psychological symptoms is likely to be less important.

Surface electromyography of jaw muscles and kinesiographic recordings: diagnostic accuracy for myofascial pain.

The present investigations attempted to assess the diagnostic accuracy of commercially available surface electromyography (sEMG) and kinesiography (KG) devices for myofascial pain of jaw muscles. Thirty-six (n = 36) consecutive patients with a research diagnostic criteria for temporomandibular disorders (RDC/TMD) axis I diagnosis of myofascial pain and an age- and sex-matched group of 36 TMD-free asymptomatic subjects underwent sEMG and KG assessments to compare EMG parameters of the masseter and temporalis muscles as well as the jaw range of motion and the interarch freeway space. EMG data at rest were not significantly different between myofascial pain patients and asymptomatic subjects, while the latter achieved significantly higher levels of EMG activity during clenching tasks. Symmetry of muscle activity at rest and during clenching tasks, KG parameters of jaw range of motion and the measurement of the interarch vertical freeway did not differ between groups. Receiver operating characteristics curve analysis showed that, except EMG parameters during clenching tasks, all the other outcome sEMG and KG measures did not reach acceptable levels of sensitivity and specificity, with a 30·6-88·9% percentage of false-positive results. Therefore, clinicians should not use sEMG and KG devices as diagnostic tools for individual patients who might have myofascial pain in the jaw muscles. Whether intended as a stand-alone measurement or as an adjunct to making clinical decisions, such instruments do not meet the standard of reliability and validity required for such usage.

Occlusion and temporomandibular disorders: a malpractice case with medical legal considerations.

Occlusion and temporomandibular The issue of temporomandibular disorders (TMD) diagnosis and treatment has become a matter of increasing interest in the medical legal field in recent years. The old-fashioned theories based on the occlusal paradigm was proven to be erroneous, and clinicians who still provide irreversible treatments to TMD patients have to be conscious of the potential legal consequences of their behavior. The present paper described an illustrative case report of a patient to whom extensive and irreversible occlusal therapies were performed with the unique aim to provide relief from TMD symptoms. The treatment was unsuccessful and the dental practitioner was called into cause for a professional liability claim. The clinician was judged guilty of malpractice on the basis of the lack of scientific evidence of the irreversible occlusal approaches to TMD, which were erroneously used and did not give the patient any benefit, thus forcing him to a non necessary financial and biological cost. The failure to satisfy the contract with the patient, which is usually not covered by any insurance company, forced the practitioner to give the money back to the patient. The ethical and legal implications of such case were discussed, with particular focus on the concept that medical legal advices need to satisfy the highest standards of evidence and have to be strictly based on scientific knowledge.

Predictive factors of hyaluronic acid injections short-term effectiveness for TMJ degenerative joint disease.

This study attempted to identify baseline predictors of positive outcome of arthrocenteses plus hyaluronic acid injections in degenerative temporomandibular joint disease (TMJ DJD). Ninety (n=90) consecutive patients with Research Diagnostic Criteria for Temporomandibular Disorders TMJ osteoarthritis (RDC/TMD 1.0 Axis I Group IIIb) underwent a cycle of five arthrocenteses with injections of 1mL hyaluronic acid and were followed up for 3months. Eight potential predictors of positive treatment outcome (sex, age, pain duration, baseline pain at chewing, presence of uni- or bilateral arthritis, presence of other concurrent RDC/TMD diagnoses, type of intervention and tolerability of treatment) were included in a logistic regression model to identify baseline predictors of treatment effectiveness. At follow-up, 85·6% of patients improved with respect to baseline VAS values, and 64·4% had a 50% or more decrease (positive outcomes). Correlation with positive outcomes existed only for unilateral osteoarthritis, and the logistic regression identified the side of arthritis (unilateral/bilateral) as the only predictor of positive treatment outcome (P=0·032). The achievement of any treatment improvement was predicted by high baseline pain levels (P=0·016). The regression models explained only 7·7-15% of the variance in the outcome variable. The attempts to find predictors of positive treatment outcome with HA injections for TMJ degenerative joint disease have been successful only in part. The search for other outcome predictors is likely to benefit from the assessment of psychosocial features associated with TMJ disorders.