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1.
Low-Profile Electromagnetic Field Sensors in the Measurement and Modelling of Three-Dimensional Jaw Kinematics and Occlusal Loading.
Woodford, SC, Robinson, DL, Edelmann, C, Mehl, A, Röhrle, O, Vee Sin Lee, P, Ackland, DC
Annals of biomedical engineering. 2021;(6):1561-1571
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Abstract
Dynamic occlusal loading during mastication is clinically relevant in the design and functional assessment of dental restorations and removable dentures, and in evaluating temporomandibular joint dysfunction. The aim of this study was to develop a modelling framework to evaluate subject-specific dynamic occlusal loading during chewing and biting over the entire dental arch. Measurements of jaw motion were performed on one healthy male adult using low-profile electromagnetic field sensors attached to the teeth, and occlusal anatomy quantified using an intra-oral scanner. During testing, the subject chewed and maximally compressed a piece of rubber between both second molars, first molars, premolars and their central incisors. The occlusal anatomy, rubber geometry and experimentally measured rubber material properties were combined in a finite element model. The measured mandibular motion was used to kinematically drive model simulations of chewing and biting of the rubber sample. Three-dimensional dynamic bite forces and contact pressures across the occlusal surfaces were then calculated. Both chewing and biting on the first molars produced the highest bite forces across the dental arch, and a large amount of anterior shear force was produced at the incisors and the second molars. During chewing, the initial tooth-rubber contact evolved from the buccal sides of the molars to the lingual sides at full mouth closure. Low-profile electromagnetic field sensors were shown to provide a clinically relevant measure of jaw kinematics with sufficient accuracy to drive finite element models of occlusal loading during chewing and biting. The modelling framework presented provides a basis for calculation of physiological, dynamic occlusal loading across the dental arch.
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2.
Bite Force Simulator: A Novel Technique to Simulate Craniofacial Strain In Vitro.
Ip, KKC, You, P, Moore, CC, Ferreira, LM
The Journal of craniofacial surgery. 2020;(3):838-842
Abstract
Existing in vitro simulators rely on external manipulation of the skull to replicate masticatory forces; however, external manipulations do not accurately represent internal loads as in physiological muscle forces.The purpose of the project is to develop an in vitro simulator that internally replicates the forces of mastication. The simulator has 3-dimensional-printed piston mounts that are reverse-engineered using a computed tomography scan of the specimen. The mounts are attached to the skull at muscle attachment sites using adhesive. The pneumatic pistons are sutured to muscle tendons; when the pistons are activated, they pull on the tendons which proportionally replicate muscle loads. The force output of the pistons can be individually modified by a custom software. Strain gauges are attached to craniofacial bones to measure deformation under replicated muscle loads. A 6 degrees-of freedom force sensor is placed intraorally to measure the generated bite force.The methodology was validated on 6 fresh-frozen cadaveric heads. Change in strain measurements was observed with change in simulated muscle loads. The simulator can validate computer simulation models and provide an experimental platform for craniofacial and dental implants. It sets the framework for a new, more physiologically consistent way of studying craniofacial stresses.
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The association between mastication and mild cognitive impairment in Korean adults.
Kim, MS, Oh, B, Yoo, JW, Han, DH
Medicine. 2020;(23):e20653
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Abstract
Currently, a few of studies revealed that there is an association between mastication and cognitive impairment. There is no study of Korean adult representative samples in relation to mastication and cognitive decline. This study was to investigate the relationship between mastication and mild cognitive impairment in Korean adults.A population-based cross-sectional study was conducted in which a total of 7029 subjects (2987 men and 4042 women) over 45 years old were surveyed from the Korea Longitudinal Study on Aging (KLoSA), Round 5th survey. Logistic regression analysis was performed for the study data controlling for confounding factors such as age, gender, education, income, smoking, drinking, exercise, wearing denture, and the number of chronic diseases.Decreased chewing function is associated with mild cognitive impairment (odds ratio [OR] = 3.24, 95% confidence interval [CI] = 2.67-3.93) after controlling for confounding variables. In the participants who did not wear dentures, the reduction of chewing function was strongly correlated with mild cognitive impairment (OR = 3.97, 95% CI = 3.11-5.08).Mastication was associated with mild cognitive impairment. To prevent cognitive decline, health specialists should pay more attention to the decline of the mastication in people without dentures.
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Impairments in Food Oral Processing in Patients Treated for Tongue Cancer.
Depeyre, A, Pereira, B, Pham-Dang, N, Barthélémy, I, Hennequin, M
Dysphagia. 2020;(3):494-502
Abstract
Patients surgically treated for oral cancer are affected by several underestimated deglutition disorders risk factors. This study aims to characterize the level of these food oral processing (FOP) impairments in a group of patients treated by surgery for tongue cancer. Twenty-seven consecutive patients surgically treated for tongue cancer were evaluated concerning their chewing capacity (Mastication-test), and responded to questions concerning their capacity to bite, chew and manipulate food with their tongue, and their quality of life. According to the Mastication-test, 16 patients suffered total FOP incapacities (TI group), characterized by high tumor stage, invasive carcinological surgery and necessity of reconstructive surgery; 12 patients were partially or not impaired (PI/NI-group). Tongue movement score and number of dental units were lower in the TI group than in the PI/NI-group. Subjective FOP criteria were clearly impaired in the TI group and correlated with a poor oral health-related quality of life. One year after surgery, there is a decrease in BMI for TI group patients while the PI group patients had a significant increase in BMI. All patients surgically treated for oral cancer suffered FOP impairments, but not with the same severity. Totally impaired subjects are at higher risk from long-term malnutrition. Functional evaluation of FOP should form part of the post-operative follow-up for all patients suffering from tongue cancer, using a quick combined evaluation of chewing efficiency, oral health quality of life and nutritional status.
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Analysis of Masticatory Muscle Activity Based on Presence of Temporomandibular Joint Disorders.
Cho, GH, Lee, Y
Medical science monitor : international medical journal of experimental and clinical research. 2020;:e921337
Abstract
BACKGROUND This study was conducted to analyze the activity of masticatory muscles depending on the presence of temporomandibular joint disorders (TMD) when foods of various hardness are masticated. MATERIAL AND METHODS We enrolled 20 subjects (13 men and 7 women) who met our selection criteria, and they were divided into 3 groups (the Disorder Group, the Malalignment Group, and the Control Group) based on surveys and screening inspection. The average of reference voluntary contraction (RVC) was used to measure masticatory muscle activity. Using surface electromyography (SEMG) for each group during masticatory activity, the activities of the masseter muscle and temporalis muscle were measured based on the hardness of 3 different foods (soft, sticky, and hard). RESULTS Characteristics of these 3 groups prior to the experiment were identical, and subsequent findings were as follows: First, when masticating sticky food, the Disorder Group and Malalignment Group showed significant differences from the Control Group in activities of the masseter muscle and temporalis muscle (p<0.05). Second, when masticating hard food, the Malalignment Group and Control Group showed significant differences from the Disorder Group in the masseter muscle and temporalis muscle activities (p<0.05). Based on these findings, the study showed that malalignment affects movement of the temporomandibular joint during mastication of sticky food, and the temporomandibular joint movement was affected by the presence of pain during mastication of hard food. CONCLUSIONS Our results provide basic data useful in the diagnosis of temporomandibular joint disorder, as well as guiding future studies on this topic.
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Effects of Neuromuscular Electrical Stimulation Synchronized with Chewing Exercises on Bite Force and Masseter Muscle Thickness in Community-Dwelling Older Adults in South Korea: A Randomized Controlled Trial.
Park, JS, Jung, YJ, Kim, MJ
International journal of environmental research and public health. 2020;(13)
Abstract
This study is aimed at investigating the effects of synchronized neuromuscular electrical stimulation (NMES) and chewing exercises on bite force and the masseter muscle thickness in community-dwelling older adults. Material and methods: Forty older adults were enrolled in South Korea and randomly assigned to either an experimental or control group. The experimental group performed chewing exercises using the No-Sick Exerciser equipment synchronized with NMES applied to the bilateral masseter muscles, while the control group performed only chewing exercises. Both groups received interventions for 20 min/day, 5 days/week, for 6 weeks. Bite force was measured using the OCCLUZER device, and masseter muscle thickness was measured using a portable ultrasound. Results: Both groups showed a significant increase in bite force and masseter muscle thickness compared to baseline measurements (p < 0.05). The experimental group showed a significantly higher increase in bite force and masseter muscle thickness than the control group after combined intervention (p < 0.05). Conclusion: This study demonstrates that NMES synchronized with chewing exercises is more efficient in increasing bite force and masseter muscle thickness than chewing exercises alone in community-dwelling older adults.
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Effects of gum chewing on glycaemic control in women with gestational diabetes mellitus: A randomized controlled trial. Impact of chewing on hyperglycaemia in women with GDM.
Yerlikaya-Schatten, G, Trimmal, L, Rosicky, I, Husslein, P, Schatten, C, Eppel, D, Eppel, W, Tura, A, Göbl, CS
European journal of obstetrics, gynecology, and reproductive biology. 2020;:61-65
Abstract
BACKGROUND The amount of chewing might be relevant in reducing hyperglycaemia in diabetic patients. The study assessed the impact of enhanced chewing on glycaemic control in women with gestational diabetes mellitus (GDM). METHODS As an open-label, mono-centre randomized controlled trial, 59 women with recent diagnosis of GDM were included. They received either routine care or additional chewing gum intervention. SMBG was performed for five days. RESULTS No significant impact on mean values of postprandial glucose levels were observed. The estimated mean differences (intervention vs. control group) were: 4.9 mg/dl, 98.4 %CI -7.2-17.1 (breakfast); -4.5 mg/dl, 98.4 %CI -15.1-6.0 (lunch); -3.8 mg/dl, 98.4 %CI -15.9 to 8.4 (dinner). OGTT levels at 60 and 120 min. were associated with glucose levels after breakfast. CONCLUSION In conclusion, no significant differences in blood glucose levels were observed between the groups and therefore major effects of chewing on hyperglycaemia in women with GDM could be excluded. TRIAL REGISTRATION ClinicalTrials.gov; NCT03961542, Date of registration: 20.01.2019. Retrospectively registered.
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Improvement in Food Intolerance Resulting from Roux-En-Y Gastric Bypass after Speech Therapy Intervention in Chewing.
Rossi, DC, Soares, AN, Silva, KRS, Britto, ATBO, Bosco, AA
Obesity surgery. 2019;(10):3195-3201
Abstract
INTRODUCTION Food intolerance is expected during the postoperative period following gastric bypass and may be associated with inadequate chewing. OBJECTIVE To evaluate chewing before and after speech therapy intervention in subjects undergoing Roux-en-Y gastric bypass who present with food intolerance. MATERIALS AND METHODS This was a randomized controlled trial, approved by the Brazilian Ethics and Research Committee under n. 438,600. The study population was allocated into two groups: the study group (SG), who received speech therapy intervention, and the control group (CG), who did not receive any intervention, in six visits at 7, 15, 30, 60, and 90 days (v7, v15, v30, v60, and v90) after the initial visit (v0). During v0 and v90, a chewing evaluation was performed according to the MBGR protocol adapted. The significance level adopted was 5%. RESULTS A total of 30 females (88%) and 4 males (12%) were analyzed. The SG had 18 subjects, and the CG had 16, with mean ages of 50.17 ± 12.28 years and 45.69 ± 9.78 years, respectively. The postoperative time ranged from 4 to19 months. In the SG, a marked improvement in the number of episodes of food intolerance was observed (p < 0.001), an improvement in the intake of cereals and meats (p = 0.004 and p < 0.001, respectively), and an improvement in chewing capacity and swallowing (p = 0.002 and p = 0.011, respectively). CONCLUSION Speech therapy intervention in chewing led to a marked improvement of food acceptance and food intolerance resulting from Roux-en-Y gastric bypass.
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Improvements in oral functions of elderly after simple oral exercise.
Kim, HJ, Lee, JY, Lee, ES, Jung, HJ, Ahn, HJ, Kim, BI
Clinical interventions in aging. 2019;:915-924
Abstract
Purpose: Conventional oral exercises in previous studies are considered impractical for continuous use in the elderly because of the extended duration needed for effective outcomes. Therefore, in the present study, a simple oral exercise (SOE) was developed to reduce performance time, focusing on improvements in mastication, salivation, and swallowing functions. The aim of this study was to determine the short-term effects of the SOE with respect to improving mastication, salivation, and swallowing function in elderly subjects ≥65 years of age. Patients and methods: The study included 84 subjects, all of whom performed the SOE 2 times per day for 1 week. Masticatory performance was assessed using the mixing ability index (MAI). Unstimulated saliva and the degree of moisture of the tongue/buccal mucosa were evaluated, and the repetitive saliva swallowing test was performed. On the basis of each of these four measurements, subjects were dichotomized into two groups with high (good) and low (poor) conditions. The same evaluations were conducted before and immediately after intervention, as well as after 1 week of intervention. A subjective evaluation with questionnaires was performed after 1 week of intervention. The changes were analyzed using repeated-measures ANOVA, Cochran's Q test, and McNemar's test. Results: The mean MAI increased by 6% immediately after the intervention, and by 16% in the poor-chewing group. Similarly, the amount of unstimulated saliva increased by 0.1 ml/min immediately after the SOE, and by 29% in the poor-salivation group. The degree of tongue moisture increased by 3% and was maintained. In the poor-swallowing group, 25% and 40% of the subjects were upgraded to the good-swallowing group immediately after intervention, as well as after 1 week of intervention, respectively. The subjects experienced less discomfort as their oral function improved. Conclusion: The SOE was effective in immediately improving oral functions, and improvement was maintained for 1 week.
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Effect of chewing rate on meal intake.
Paphangkorakit, J, Kanpittaya, K, Pawanja, N, Pitiphat, W
European journal of oral sciences. 2019;(1):40-44
Abstract
Fast eating has been shown to increase the risk of overweight in both children and adults. The objectives of the present study were to investigate the correlation between chewing rate and the number of chews per mouthful and to evaluate if they were associated with the weight of meal intake. Thirty healthy subjects, aged 18-24 yr, ate a test lunch at their habitual speed until they felt satiated. The activities of masseter and suprahyoid muscles were recorded to determine the number of chews and the moment of swallowing. The weight of meal intake was recorded along with body mass index (BMI), chewing rate, number of chews per mouthful, meal duration, ingestion rate, hunger, and food preference levels. The mean weight (±SD) of meal intake, chewing rate, and number of chews per mouthful were 261.4 ± 78.9 g, 94.4 ± 13.5 chews min-1 , 19.2 ± 6.4 chews per mouthful, respectively. Chewing rate was not correlated with the number of chews per mouthful. The multivariable linear regression showed that meal intake was significantly positively associated with chewing rate, meal duration, and BMI, but inversely associated with the number of chews per mouthful (adjusted R2 = 0.42). It was concluded that the number of chews was not associated with chewing rate but meal intake was explained by both reduced number of chews and increased chewing rate.