Search

Background: Occlusal interferences lead to changes in mandibular kinematics to compensate and improve function. However, the effects of different types of eccentric disturbance on the comminution capacity are not known. Objective: To determine the immediate effect of eccentric occlusal interferences on masticatory performance. Methods: This crossover clinical trial included 12 healthy dentate subjects aged 25.2 ± 3.3 years who were randomly submitted to seven types of occlusal interference: unilateral and bilateral laterotrusive and mediotrusive, protrusive, dummy and control (no interference). The interference forms were planned in a semi‐adjustable articulator, fabricated with composite resin and adhered to the mandibular first molars such that subjects' maximum intercuspation was maintained. Masticatory performance and the chewing rate during 20 cycles were evaluated during subjects' comminution of silicone test food under one interference condition per test day; the multiple sieve method was applied to the comminuted particles. The interference was removed upon test completion, and a 1‐week washout period was applied between tests. Results: Comminuted median particle sizes were larger under unilateral (4.94 ± 0.41 mm) and bilateral (4.81 ± 0.49 mm) laterotrusive, bilateral mediotrusive (4.65 ± 0.50 mm) and protrusive (4.83 ± 0.54 mm) interferences (p <.05) than under the control (4.01 ± 0.52 mm) and dummy (4.18 ± 0.58 mm) conditions (p <.05). Only unilateral and bilateral laterotrusive interferences narrowed the comminuted particle size dispersion (p <.05). The chewing rate did not differ among conditions (p =.1944). Conclusion: Artificial eccentric interferences had an immediate adverse effect on masticatory performance by resulting in larger comminuted particles. Clinical trial registration: Brazilian Registry of Clinical Trials (RBR‐8g5zfg8). [ABSTRACT FROM AUTHOR]

Purpose: To assess the correlation between RDC/TMD Axis I and Axis II diagnoses and whether pain could mediate a possible correlation between these two variables.Materials and Methods: Data of both RDC/TMD axes were collected from 737 consecutive patients who sought TMD advice at the University of Padova, Italy. A descriptive analysis was used to report the frequencies of Axis I and II diagnoses, and Spearman test was performed to assess the correlation between the axes. Subsequently, the sample was divided into two groups (painful vs nonpainful TMD). Frequencies were reported using descriptive analysis, and chi-square test was used to compare groups. The painful TMD group was then divided based on the level of pain-related impairment (low = Groups I and II; high = Groups III and IV). Then, frequencies of depression and somatization were reported using descriptive analysis for each disability group, and chi-square test was used to compare groups.Results: No correlation levels were found between Axis I and any of the Axis II findings (Graded Chronic Pain Scale, depression, and somatization). The painful TMD group presented higher levels of depression and somatization (P < .05). Comparisons of depression and somatization frequencies between pain-impairment groups showed a significantly higher prevalence of abnormal scores for the severe pain-impairment group.Conclusion: There is no correlation between specific Axis I and Axis II findings. The presence of pain, independent of the muscle or joint location, is correlated with Axis II findings, and higher levels of pain-related impairment are associated with the most severe scores of depression and somatization. [ABSTRACT FROM AUTHOR]

Aims: To determine sleep quality and associated factors in a group of patients with painful TMDs. Methods: The medical records of 80 patients with arthralgia and/or myofascial pain were reviewed and compared to a healthy control group. Data about sex, age, subjective pain, physical activity, social activity, subjective sleep quality (Pittsburgh Sleep Quality Index [PSQI]), pain vigilance (Pain Vigilance and Awareness Questionnaire [PVAQ]), and pain catastrophizing (Pain Catastrophizing Scale [PCS]) were collected. Relationships between PSQI, age, pain intensity, PVAQ, and PCS in the TMD group were also analyzed. Data from the control group were used to transform the PSQI results into T-scores, which were then used to divide the TMD group into two subgroups: normal and impaired sleep. Results: TMD patients presented a significantly higher (P < .001) PSQI score than the control group. Also, in the TMD group, there was a low to moderate correlation between PSQI and pain intensity and a significant correlation between PVAQ and PCS. The impaired sleep group presented a significantly higher (P < .001) PSQI T-score than the normal sleep group. Univariate analysis showed that subjective pain, social activity, and the PCS total and subscale scores differed significantly between the different PSQI T-score groups. The comparison between TMD pain patients and control subjects showed a significantly higher prevalence of T-score discordance in almost all PSQI components in TMD patients with impaired sleep. Conclusion: Subjective sleep quality in painful TMD patients could be associated with and influenced by psychosocial factors (catastrophizing and hypervigilance), social activity, and pain intensity. [ABSTRACT FROM AUTHOR]

Aims: To determine whether there is an association between gene polymorphisms and patients with painful temporomandibular joint (TMJ) clicking when compared to patients with painless TMJ clicking and a healthy control group. Methods: In this pilot study, the genotypic and allelic frequencies of candidate single-nucleotide polymorphisms (SNP) were compared among 60 individuals divided equally into three groups: patients with painful TMJ clicking (n = 20); patients with painless TMJ clicking (n = 20); and healthy controls (n = 20). Participants were genotyped for the following SNPs using real-time polymerase chain reaction: MMP1 --16071G/2G, COMT Val158Met, TNFα --308, IL1β +3954, IL6 --174, and IL10 --1082. The pressure pain threshold (PPT) of the TMJ was also assessed. All variables were compared among groups. Results: Patients with painful TMJ clicking had a significant association and a higher frequency of MMP1 --16071G/2G (P = .042), COMT Val158Met (P = .030), and TNFα --308 (P = .016) when compared to the other groups, as well as a lower frequency of IL10 --1082. Considering PPT values, a progressively lower mean was found in individuals with painful TMJ clicking, followed sequentially by the painless TMJ clicking and the control groups. Conclusion: This pilot study showed that patients with painful TMJ clicking had a significant association with mutant genotypes related to degradation of extracellular matrix components, pain, proinflammation, and anti-inflammation. Furthermore, these patients also had significantly lower TMJ PPT values in all comparisons. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to evaluate the effect of frozen storage on the physical properties of a silicone-based test food material, highly used to evaluate the masticatory performance in research settings. Methods: A total of 1,666 silicone cubes of Optosil Comfort® with 5.6-mm edges were shaped and stored at -18°C. The cubes were subsequently tested for flexural strength (maximum force, displacement, stress, and strain) before breaking (n = 136), changes in weight and size (n = 170), and masticatory performance (n = 1360) at eight timepoints: immediately after cube preparation (baseline, no freezing), and 1, 2, 3 and 4 weeks, and 2, 4 and 6 months after frozen storage. The cubes were thawed 8 h before each assessment. Results: The maximum force, stress, maximum displacement, and deformation values for the cubes were not affected by freezing (P > 0.05). At all of the time points, the cubes exhibited similar weight (P = 0.366) and size (identical values). The masticatory performance for the cubes also showed no differences from baseline through 6 months (P = 0.061). Conclusion: Freezing Optosil Comfort® silicone cubes did not alter the physical and mechanical properties of the material, being suitable to optimize the assessment of masticatory parameters for research purposes. [ABSTRACT FROM AUTHOR]

The present cross-sectional case-control study aimed to determine if there is an association between specific oral behaviors, sleep bruxism (SB), awake bruxism (AB), and painful temporomandibular joint (TMJ) clicking. Ninety individuals were dived into three groups; Group 1 (n = 30): painful TMJ clicking; Group 2 (n = 30): painless TMJ clicking; and Group 3 (n = 30): control group. The following clinical data were studied: oral behaviors (unilateral chewing, gum chewing, nail biting, foreign objects biting, leaning with jaw against the hand, and sleeping in a position that pressures the jaw), SB, AB (including the frequency in 10 days, evaluated by ecological momentary assessment), and malocclusions investigated based on clinical inspections (anterior open bite, posterior cross-bite, abnormal overbite/overjet, occlusal guidance, mediotrusive and/or laterotrusive interferences, retruded contact position to maximum intercuspation slide, missing posterior teeth). All statistical tests (Kolmogorov-Smirnov, chi-square, and one-way ANOVA) were performed with a 5% significance level. Group 1 had the highest frequency of and a significant association with leaning with jaw in the hand, sleeping position that pressures the jaw, gum chewing, nail biting, and AB (p<0.05). Gum chewing, nail biting, and AB were associated with Group 2 only when compared to Group 3 (p<0.05). No significant difference among groups was found for other behaviors (unilateral chewing and foreign objects biting), SB, and all malocclusions (p>0.05). It can be concluded that patients with painful TMJ clicking had a higher frequency of and a significant association with some specific harmful behaviors and AB. [ABSTRACT FROM AUTHOR]

Aims: To systematically review the literature to assess whether genetic polymorphisms affect orofacial pain sensitivity in healthy individuals and in patients with chronic orofacial pain disorders. Methods: Electronic searches were conducted to identify observational studies and clinical trials investigating the association between genetic polymorphisms and orofacial pain sensitivity in healthy individuals and/or patients with chronic orofacial pain disorders. Searches were carried out in PubMed, Embase, and Scopus databases using Medical Subject Headings and free terms. Results: Seven studies fulfilled the eligibility criteria: four analyzed healthy subjects, two included chronic orofacial pain patients, and one included samples of healthy subjects and patients with neuropathic pain. The results showed that genes associated with mechanical and thermal pain sensitivity were mostly related to opioid, catecholaminergic, inflammatory, and dopaminergic pathways. Conclusion: Genetic polymorphisms related to opioid, catecholaminergic, inflammatory, and dopaminergic pathways were associated with sensitivity to thermal and pressure stimuli in the orofacial region. Therefore, genetic factors should be taken into account for an accurate interpretation of orofacial pain sensitivity. These results will allow for a better understanding of the etiopathogenesis of chronic pain affecting the orofacial region, and consequently for finding new therapeutic targets. [ABSTRACT FROM AUTHOR]

Masticatory muscle pain (MMP) is a common type of orofacial pain. Occlusal appliance (OA) is contemplated as a first-line conservative approach for chronic MMP, however, integrated biopsychosocial approaches such as counseling and self-care therapies (CSG) are also considered essential. Aim: This pilot study aimed to compare the use of a combined therapy (GSG + OA) and solely OA treatment on pain intensity related to chronic MMP over a 6-month follow-up. Methods: For this, 20 patients diagnosed with chronic MMP using the Diagnostic criteria for temporomandibular disorders (DC/TMD) were divided into 2 groups (n=10) and treated with OA or combined therapy (CoT; OA + CSG). Electromyographic muscle activity (EMG), visual analogue scale (VAS) and pressure pain threshold (PPT) were recorded at baseline, 1, 3 and 6 months after treatment. Data was collected and statistical analysis were applied at a significance level of 5%. Results: Results showed no significant differences at baseline among groups for any assessment. VAS showed that both treatments decreased subjective pain in volunteers over time, but no significant differences among both groups were observed at any evaluation time. For electromyography, CoT and OA presented no significant differences throughout the experiment neither on relaxed muscle position or maximum volunteer contraction. Finally, a significantly higher PPT for CoT was found for all muscles at the last assessment point (p<0.05). Conclusion: These findings suggest that both treatments are effective for the reduction of pain perception (VAS) in patients with chronic MMP. However, the addition of CSG to an OA therapy may be more beneficial for the improvement of tenderness on the same patients, at least in a long-term basis (> 3 months). Notwithstanding, a larger study should be performed to substantiate these findings. [ABSTRACT FROM AUTHOR]