Is low back pain a risk/prognostic factor for the development and/or progression of temporomandibular disorders? A systematic review with meta-analysis.

OBJECTIVES: To evaluate the association between low back pain (LBP) and painful temporomandibular disorders (TMDs). METHODS: Systematic review of observational studies. Searches were conducted using OVID MEDLINE, CINHAL, Web of Science and PUBMED databases up to 21 October 2022. Qualitative and quantitative analyses were performed. Risk of bias (RoB) was assessed using the Quality in Prognosis Studies tool (QUIPS). RESULTS: Eight studies were included in the present review with meta-analysis. The first onset of TMDs was more likely in patients with previous chronic LBP (hazard ratio (HR) 1.53 [95% confidence interval (CI): 1.28; 1.83, p < .00001]). In addition, patients with chronic LBP had 3.25 times the odds (OR) [95% CI: 1.94; 5.43, p < .00001] of having chronic TMDs than those who did not have chronic LBP. In addition, the higher the exposure to chronic LBP, the higher the risk of developing a first onset of TMDs. CONCLUSIONS: Chronic LBP can be considered a risk/contributing factor for painful TMDs. Although there is a high certainty in the evidence linking chronic LBP with the risk of a first onset of TMDs, there are insufficient studies to draw definitive conclusions. Furthermore, while an association between chronic LBP and chronic TMDs and a dose-effect was observed between these two conditions, a limited number of studies and evidence exist to support these findings. Future studies are needed to increase the body of evidence.

Factors predicting persistence of biologic drugs in psoriasis: a systematic review and meta-analysis.

BACKGROUND: Long-term therapy for psoriasis is impaired by gradual loss of effectiveness and treatment discontinuation. Identifying factors that affect biologic drug survival may help in treatment optimization. OBJECTIVES: To identify factors that predicted biologic drug persistence or discontinuation in a real-life setting. METHODS: We identified studies of biologic persistence in psoriasis through a comprehensive, systematic literature search using predefined search criteria. Studies were screened by title and abstract then further by full-text review. Hazard ratio (HR) data were extracted for all available predictive factors (HRs > 1 denoted biologic discontinuation, and HRs < 1 denoted biologic persistence). A meta-analysis of HRs (random-effects model) was used to assess any predictive factor included in at least two studies. RESULTS: Sixteen cohort studies were included in the review, with a total of 32 194 patients. A meta-analysis was performed on 13 studies (n = 29 802): nine for female sex (n = 28 090), six for obesity (n = 9311) and six for psoriatic arthritis (n = 24 444). Obesity and female sex predicted treatment discontinuation, with HRs of 1.21 [95% confidence interval (CI) 1.10-1.32, I2 = 0%] and 1.22 (95% CI 1.07-1.38, I2 = 84%), respectively. Concomitant psoriatic arthritis predicted biologic persistence (HR 0.83, 95% CI 0.80-0.86, I2 = 0%). Female sex predicted biologic discontinuation due to side-effects, with a pooled HR of 2.16 (95% CI 1.39-3.35, I2 = 67%). Other reported predictive factors (smoking, metabolic syndrome, biologic naivety, age, Dermatology Life Quality Index, dyslipidaemia, high socioeconomic status and concomitant methotrexate) were insufficiently reported for meta-analysis. CONCLUSIONS: Our meta-analysis demonstrates that female sex and obesity predict biologic discontinuation, and concomitant psoriatic arthritis predicts biologic survival. What's already known about this topic? Ineffectiveness is the main factor that causes drug discontinuation during long-term treatment of psoriasis. It is unclear which factors and comorbidities impact drug persistence. What does this study add? Female sex and obesity predict biologic discontinuation due to ineffectiveness and adverse events. Concomitant psoriatic arthritis is associated with improved drug persistence.

Impact of Selection Bias on Treatment Effect Size Estimates in Randomized Trials of Oral Health Interventions: A Meta-epidemiological Study.

Emerging evidence suggests that design flaws of randomized controlled trials can result in over- or underestimation of the treatment effect size (ES). The objective of this study was to examine associations between treatment ES estimates and adequacy of sequence generation, allocation concealment, and baseline comparability among a sample of oral health randomized controlled trials. For our analysis, we selected all meta-analyses that included a minimum of 5 oral health randomized controlled trials and used continuous outcomes. We extracted data, in duplicate, related to items of selection bias (sequence generation, allocation concealment, and baseline comparability) in the Cochrane Risk of Bias tool. Using a 2-level meta-meta-analytic approach with a random effects model to allow for intra- and inter-meta-analysis heterogeneity, we quantified the impact of selection bias on the magnitude of ES estimates. We identified 64 meta-analyses, including 540 randomized controlled trials analyzing 137,957 patients. Sequence generation was judged to be adequate (at low risk of bias) in 32% ( n = 173) of trials, and baseline comparability was judged to be adequate in 77.8% of trials. Allocation concealment was unclear in the majority of trials ( n = 458, 84.8%). We identified significantly larger treatment ES estimates in trials that had inadequate/unknown sequence generation (difference in ES = 0.13; 95% CI: 0.01 to 0.25) and inadequate/unknown allocation concealment (difference in ES = 0.15; 95% CI: 0.02 to 0.27). In contrast, baseline imbalance (difference in ES = 0.01, 95% CI: -0.09 to 0.12) was not associated with inflated or underestimated ES. In conclusion, treatment ES estimates were 0.13 and 0.15 larger in trials with inadequate/unknown sequence generation and inadequate/unknown allocation concealment, respectively. Therefore, authors of systematic reviews using oral health randomized controlled trials should perform sensitivity analyses based on the adequacy of sequence generation and allocation concealment.

Psychometric evaluation of a motor control test battery of the craniofacial region.

The primary objective of this study was to determine the structural and known-group validity as well as the inter-rater reliability of a test battery to evaluate the motor control of the craniofacial region. Seventy volunteers without TMD and 25 subjects with TMD (Axes I) per the DC/TMD were asked to execute a test battery consisting of eight tests. The tests were video-taped in the same sequence in a standardised manner. Two experienced physical therapists participated in this study as blinded assessors. We used exploratory factor analysis to identify the underlying component structure of the eight tests. Internal consistency (Cronbach's α), inter-rater reliability (intra-class correlation coefficient) and construct validity (ie, hypothesis testing-known-group validity) (receiver operating curves) were also explored for the test battery. The structural validity showed the presence of one factor underlying the construct of the test battery. The internal consistency was excellent (0.90) as well as the inter-rater reliability. All values of reliability were close to 0.9 or above indicating very high inter-rater reliability. The area under the curve (AUC) was 0.93 for rater 1 and 0.94 for rater two, respectively, indicating excellent discrimination between subjects with TMD and healthy controls. The results of the present study support the psychometric properties of test battery to measure motor control of the craniofacial region when evaluated through videotaping. This test battery could be used to differentiate between healthy subjects and subjects with musculoskeletal impairments in the cervical and oro-facial regions. In addition, this test battery could be used to assess the effectiveness of management strategies in the craniofacial region.

Jaw dysfunction is associated with neck disability and muscle tenderness in subjects with and without chronic temporomandibular disorders.

PURPOSE: Tender points in the neck are common in patients with temporomandibular disorders (TMD). However, the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with TMD still needs further investigation. This study investigated the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with and without chronic TMD. Participants. Forty females between 19 and 49 years old were included in this study. There were 20 healthy controls and 20 subjects who had chronic TMD and neck disability. METHODS: Subjects completed the neck disability index and the limitations of daily functions in TMD questionnaires. Tenderness of the masticatory and cervical muscles was measured using an algometer. RESULTS: The correlation between jaw disability and neck disability was significantly high (r = 0.915, P < 0.05). The correlation between level of muscle tenderness in the masticatory and cervical muscles with jaw dysfunction and neck disability showed fair to moderate correlations (r = 0.32-0.65). CONCLUSION: High levels of muscle tenderness in upper trapezius and temporalis muscles correlated with high levels of jaw and neck dysfunction. Moreover, high levels of neck disability correlated with high levels of jaw disability. These findings emphasize the importance of considering the neck and its structures when evaluating and treating patients with TMD.

Quality of reporting masticatory muscle electromyography in 2004: a systematic review.

This study evaluated the quality of reporting electromyography in studies evaluating the masticatory muscles published during 2004. Several electronic databases were searched. Abstracts and later articles were selected by a consensus from the five reviewers. An adaptation of the methodological checklist published by the International Society of Electrophysiology and Kinesiology (ISEK) was used. The following information regarding electrodes was reported on the 35 finally selected articles: location (94.3%), interelectrode distance (48.6%), and material (42.9%); detection and amplification: amplification type (54.3%), gain (25.7%), low high pass filters (60%) and cut-off frequencies (60%); electromyography (EMG) processing: sampling rate (74.2%), rectification (46.6%), root-mean square (RMS) (39.2%); number of bits and model of A/D card (17.1%); and normalization procedure (40%). Reasons for the poor reporting are discussed. Because of the general poor quality of reporting of the analysed studies, findings of studies using surface electromyography of masticatory muscles should be interpreted with caution.

Electromyographic activity of the masticatory and cervical muscles during resisted jaw opening movement.

One of the relaxation techniques that have been used by physical therapists when treating patients with temporomandibular disorders, is the agonist contract-antagonist relax technique (AC). When the AC technique is applied, a submaximal resistance to the jaw opening movement is necessary to cause relaxation of the masticatory muscles. No information about the effect of this technique on masticatory or cervical muscles has been found in the literature. Thus, the aim of this study was to evaluate the electromyographic activity of the masseter and anterior temporalis and the upper trapezius and splenius capitis during resisted jaw opening movement. A convenience sample of 30 students was used. Electromyography activity of the superficial masseter, anterior temporalis, upper trapezius and splenius capitis was registered before, during and after the application of this resistive movement to jaw opening. A two-way anova with repeated measures analysis was used to analyse data. The level of significance was at alpha = 0.05. The EMG activity of both the masticatory muscles and the cervical muscles increased during and after the application of resisted jaw opening (P < 0.05). Based on the results obtained from this study, the behaviour of all muscles analysed (masseter, anterior temporalis, splenius capitis and upper trapezius) was similar. All muscles increased their activity when the resistance to the jaw opening movement was applied. Complex muscular interactions of the supra- and infrahyoid muscles (jaw openers), masticatory muscles, and cervical muscles may exist to stabilize the craniomandibular system during resisted jaw opening.

A comparison of the head and cervical posture between the self-balanced position and the Frankfurt method.

Head and cervical posture evaluation has been a concern for many years, not only because of the purported relationship that exists between head and cervical posture in the presence of temporomandibular disorders, neck pain and headache, but also because of the biomechanical relationship between the head and cervical spine and dentofacial structures. Many methods have been suggested in an attempt to establish the best way to evaluate the position of the head using teleradiographs and cephalometric analysis. However, there is still no agreement as to which procedure is the best. The objective of this study was to evaluate the differences that exist between craniocervical measurements in lateral teleradiographs when comparing the position of the head in the self-balanced position to the position of the head using the Frankfurt method (Frankfurt plane parallel to the floor). Sixty-eight subjects who sought dental treatment in community health centres in Talca, Chile participated in this study. Rocabado analysis was used to measure the craniocervical variables. The Cobb analysis was used to measure cervical lordosis. A paired student t-test was used to evaluate the differences between both procedures, using an alpha of 0.05 and a power of 0.90. The use of the cephalostat changed only the craniocervical angle (P < 0.001). However, this change was minimal. No changes related to gender and age were found. More studies are needed to determine the variation between different procedures and to define a good procedure for evaluating head posture.