Signal to noise ratio of masticatory muscle activity of functional and non-functional oral tasks.

BACKGROUND: Electromyographic activity (EMG) of masticatory muscles during wakefulness is understudied. It is unclear if single channel ambulatory EMG devices are sensitive enough to detect masticatory muscle activity (MMA) during wakefulness. OBJECTIVES: To compare the MMA of various oral tasks recorded with a single channel EMG device ((Grindcare4-datalogger Prototype device) (GC4-ß)) and a conventional EMG (cEMG) device. METHODS: EMG activity of 30 standardised oral tasks was recorded unilaterally from the masseter and anterior temporalis muscle in 24 healthy volunteers using GC4-ß and a cEMG device. To compare the EMG data, signal-to-noise ratios (SNR) were calculated as a way to normalise EMG activity across tasks. Analysis of variance was used to compare the SNR between the devices, muscles and oral tasks. RESULTS: SNR measured from GC4-ß was overall significantly higher than the cEMG device (p =.001). The SNR for maximum voluntary contraction (MVC) was significantly higher than all other tasks (p <.001). SNR for temporalis with GC4-ß was significantly higher for MVC, hard food, soft food, gum chewing (dominant side), rhythmic clenching and upper lip biting compared to the cEMG device (p <.021). The SNR for masseter with GC4-ß was significantly higher for hard food and gum chewing (dominant side), rhythmic clenching, rhythmic biting of an object and yawning compared to the cEMG device (p <.022). CONCLUSIONS: This study provides novel insight into the EMG patterns of numerous oral tasks enhancing knowledge of physiological differences between the masticatory muscles. Further, single channel EMG devices can effectively measure the EMG activity of various oral tasks during wakefulness.

Internal structure and validity of the bedside oral examination tool in patients with brain injury at neurorehabilitation setting.

OBJECTIVES: To assess the internal structure and validity of the 'bedside oral examination' (BOE) instrument in individuals with acquired brain injury (ABI). METHODS: Ninety ABI individuals were examined using BOE in their first week of neurorehabilitation. BOE measures oral health within eight categories including: swallow, tongue, odour, teeth, lips, saliva, mucosa and gingiva. To assess the validity of BOE, full-mouth clinical examination (gold standard) was performed. The internal structure of BOE was assessed using exploratory and confirmatory factor analyses. To measure the validity, the BOE scores were dichotomised into excellent oral health and altered oral health. Sensitivity, specificity and area under the receiver operating characteristic (ROC) curve of the six/eight BOE items were compared with their related clinical oral examination tool. RESULTS: Overall, the patients had poor oral health irrespective of the oral examination tool used. Factor analyses indicated two factors within BOE: 'oral hygiene' (teeth, gingiva and mucosa) and 'orofacial health' (lips, swallow and saliva). BOE tongue and odour items loaded in neither factor. BOE items showed low validity since the highest area under the ROC curve was 0.60. Findings on the sensitivity value ranged from 35.0 to 74.2, while specificity from 44.4 to 83.3, depending on the item evaluated. CONCLUSION: Bedside oral examination does not seem to be an ideal 'single' outcome tool in a neurorehabilitation setting as it lacks validity. BOE evaluates oral health as two independent but correlated components and treat them separately indicating precision treatment depending on their oral health dysfunction. It is advisable to use BOE as a screening tool. However, it should be complimented by proper clinical examination before establishing a treatment plan for oral health in patients with ABI.

Changes in oral health related quality of life and its associated factors in individuals with brain injury.

Purpose: To evaluate changes in oral health-related quality of life (OHRQoL) and associated factors in individuals with acquired brain injury (ABI) during hospitalization.Methods: Forty-six individuals with ABI were examined at week 1 and 5 of hospitalization. OHRQoL was recorded through Oral Health Impact Profile-14 (OHIP-14), clinical oral examinations were conducted, while orofacial health-related 'motor' and 'cognitive' scores were retrieved from patients' e-journal. Association between variables were investigated using factor analysis and multilevel regression modeling.Results: There were no significant differences in the OHIP-14 scores between week 1 and 5. Factors analysis revealed two OHIP-14 domains, 'psychosocial' and 'physica'. Individuals who improved their cognitive skills over study period and those with 'severe' periodontitis at baseline had increased scores of OHIP-14 'psychosocial' domain. Individuals who improved orofacial health-related 'motor' skills over study period had decreased 'physical' domain scores. Increased cognition over study period, current smoking and dental calculus were associated with increased 'physical' domain.Conclusions: The OHRQoL was poor both at week 1 and 5. Individual's cognitive and motor skills as well as their oral health status influenced their OHRQoL. Thus, individual's awareness and involvement in addition to oral care seem to be imperative in improving the OHRQoL in neurorehabilitation setting.

Effects of mouth rehabilitation with removable complete dentures on stimulus perception and the electromyographic activity of the orbicularis oris muscle.

STATEMENT OF PROBLEM: Many elderly individuals are rehabilitated with removable complete dentures, which require an initial adaptation period for both oral perception and the perioral muscles. Studies assessing the changes in stimulus perception and the electromyographic (EMG) activity of the orbicularis oris muscle shortly after conventional complete denture insertion are lacking. PURPOSE: The purpose of this clinical study was to evaluate the effect of mouth rehabilitation with removable complete dentures on stimulus perception and the EMG activity of the orbicularis oris muscle. MATERIAL AND METHODS: This study was approved by the Human Research Ethics Committee of the Araçatuba Dental School (São Paulo State University). Fifteen participants who had worn their removable complete dentures for at least 5 years and needed rehabilitation with new prostheses were enrolled in the study. A perception questionnaire was applied, and surface EMG examinations of the orbicularis oris muscle during rest, suction of water with a straw, and pronunciation of the syllables /bah/, /mah/, /pah/, and the word 'Mississippi' were performed before (T0) and 30 (T1) and 100 (T2) days after insertion of the new prostheses. The data were analyzed with the Cochran Q test, McNemar test, 2-way repeated measures ANOVA, and honestly significant difference (HSD) Tukey test (α=.05). RESULTS: Significant improvement was reported in the perception questionnaire in terms of the oral discomfort sensation in the T2 period. EMG activity decreased during rest and suction after insertion of the new prostheses. A statistical difference between the upper and lower fascicles of the orbicularis oris muscle was detected, with a decrease of EMG activity between the T0 and T1 periods on the lower fascicle, except for when pronouncing the /pah/ syllable. CONCLUSIONS: Mouth rehabilitation with removable complete dentures decreased oral discomfort and, depending on the oral function, decreased or increased EMG activity of the orbicularis oris muscle. In addition, the lower fascicle was more active than the upper fascicle during rest and most functional activities.