Influence of awake bruxism behaviors on fatigue of the masticatory muscles in healthy young adults

Abstract The present cross-sectional study aimed to analyze the relationship between awake bruxism and fatigue of masticatory muscles in healthy young adults. For this purpose, 121 graduate students participated in this study. Frequency of awake bruxism was collected for 7 consecutive days by ecological momentary assessment (EMA) using an online survey (mentimeter). Muscle fatigue was tested one day after EMA assessment, which consisted of voluntarily and continuously clenching at 30% (kgf/cm2) of maximum bite force (MBF) until exhaustion. The percentage of change in MBF after the clenching task, as compared to the MBF before the clenching task was measured. The average frequency of awake bruxism was 45.5% during 7 days. Sustained clenching resulted in a significant reduction in MBF values in the total sample (p < 0.05). Nevertheless, no significant correlation was found between frequency of awake bruxism behaviors and percent of change in MBF and endurance time during the fatigue test. Therefore, it can be concluded that young healthy adults present a relatively high frequency of awake bruxism behaviors that do not seem to impact the degree of masticatory muscle fatigue.

The association of self-reported awake bruxism with anxiety, depression, pain threshold at pressure, pain vigilance, and quality of life in patients undergoing orthodontic treatment

Abstract This study aimed to evaluate whether the presence of awake bruxism was associated with temporomandibular dysfunction symptoms, pain threshold at pressure, pain vigilance, oral health-related quality of life (OHRQoL), and anxiety and depression symptoms in patients undergoing orthodontic treatment. Methodology This observational study followed patients who had started receiving orthodontic treatment for six months. The following variables were measured three times (at baseline, one month, and six months): pressure pain threshold (PPT) in the right and left masseter, anterior temporalis, and temporomandibular joint (TMJ), and right forearm; pain vigilance and awareness questionnaire; and shortened form of the oral health impact profile (OHIP-14). Anxiety and depression symptoms were measured using the Beck anxiety inventory and the Beck depression inventory, respectively. The patients were divided into two main groups according to the presence (n=56) and absence (n=58) of possible awake bruxism. The multi-way analysis of variance (ANOVA) was applied on the date (p=0.050). Results TMJ and/or muscle pain were not observed in both groups. Time, sex, age group, and awake bruxism did not affect the PPT in the masticatory muscles and pain vigilance (p>0.050). However, the primary effect of awake bruxism was observed when anxiety (ANOVA: F=8.61, p=0.004) and depression (ANOVA: F=6.48, p=0.012) levels were higher and the OHRQoL was lower (ANOVA: F=8.61, p=0.004). Conclusion The patients with self-reported awake bruxism undergoing an orthodontic treatment did not develop TMJ/masticatory muscle pain. The self-reported awake bruxism is associated with higher anxiety and depression levels and a poorer OHRQoL in patients during the orthodontic treatment.

Collagenous matrix as a predictor for bone formation: a digital technique for collagen quantification

The collagenous matrix plays a fundamental role in the process of bone regeneration, so it is essential to study how it is primarily formed in situations in which critical bone defects are created. Objective: this study seeks to quantify the collagenous matrix formed in critical bone defects in the calvaria of mice over the process of bone regeneration promoted by the association of poly(lactide-co-glycolide) (PLGA) porous scaffolds and stem cells from deciduous teeth (SCDT). In addition, this study attempted to establish a precise protocol for the digital quantification of collagen through a histological method. Materials and method: Nine Wistar rats were used, in which critical defects of 8.0 mm of diameter were made in their calvarium. The animals were divided into three groups (n = 9): I ­ PLGA scaffolds; II ­ PLGA scaffolds/SCDT; III ­ PLGA scaffolds/SCDT maintained in osteogenic medium for 13 days. Within sixty postoperative days, calvaria were removed for histometric analysis following a digital protocol. A specific digital analysis method was designed for this study, in which a more precise quantification and differentiation between collagen fibers and non-collagenous tissue was possible, excluding factors that would normally alter the results. Results: it was noted that the association of PLGA scaffolds and SCDT maintained in osteogenic medium resulted in collagen matrix formation statistically higher than the other groups (p<0.05). Conclusion: the protocol designed for collagen quantification was precise and efficient, producing methodologically standardized results.