• Research in Community and Public Health Nursing
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• v.28 no.3
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• pp.302-312
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• 2017

Purpose: The purpose of this study was to identify associated factors of chewing discomfort among community-dwelling elderly. Methods: The study was cross-sectional design and secondary data analysis using the 6th Korea National Health and Nutrition Examination Survey. Among the total of 7,550 participants, data was analyzed with 1,126 adults aged 65 years and over. Chewing discomfort was assessed by the perceived chewing discomfort. Multivariate logistic regression analysis was used to find the associated factors of chewing discomfort. Results: Along with 61.7% of the participants reported having chewing discomfort, 85.2% reported to perceive poor oral health and 35.0% had oral pain. In multivariate logistic regression, perceived oral health (OR 3.22, 95% CI 2.24~4.63), oral pain (OR 2.46, 95% CI 1.76~3.43), activity limitation (OR 1.71, 95% CI 1.05~2.80), teeth requiring treatment (OR 1.61, 95% CI 1.14~2.26), number of remaining teeth (OR 1.60, 95% CI 1.22~2.10) and educational level (OR 1.56, 95% CI 1.15~2.12) were the significant predictors of chewing discomfort. Conclusion: The prevalence in chewing discomfort was high in elderly Koreans and various factors were associated with chewing discomfort. To improve chewing ability, it is suggested that the national level of policies offer strategical oral health programs in this population.

• Journal of Oral Medicine and Pain
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• v.48 no.4
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• pp.159-168
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• 2023

Purpose: Coordinated activity between the jaw and neck muscles is important in oral motor tasks such as chewing. This study examined coherence between the jaw and neck muscles during chewing in healthy adults. Methods: A total of 12 healthy adults underwent electromyography (EMG) of the jaw and neck muscles during right-sided chewing at a frequency of 1 Hz. Surface electrodes were placed over the temporalis (TA), masseter (MS), anterior digastric (DA), and sternocleidomastoid (SM) muscles on the right side. EMG signals were processed for coherence and phase analysis using advanced signal processing techniques. Results: The MS and TA muscle pair exhibited high synchronization when chewing (median coherence=0.992). Contrarily, the coherence values between the MS and DA, as well as the MS and SM muscle pairs, were relatively low (median coherence=0.848 and 0.957, respectively). Phase analysis revealed minimal temporal differences between the MS and TA muscle pair and the MS and SM muscle pair, whereas substantial phase shifts were observed between the MS and DA muscle pair. Conclusions: During chewing in healthy adults, the TA muscle works synergistically whereas the DA muscle antagonistically with the MS muscle, and the SM muscle supports the activity of the MS muscle. The observed synchrony and coordination provide insights into the intricate interplay among these muscles during oral motor tasks.

• Journal of the Korean Dietetic Association
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• v.29 no.4
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• pp.248-260
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• 2023

This study provides basic data when planning nutrition support for healthy aging by revealing the relationship between various symptoms in the elderly and nutrient intake. From the 8th National Health and Nutrition Examination Survey, data from senior citizens aged 65 years or older in 2021 were used, and answers on the depression prevalence, activity restrictions, complaints of discomfort when chewing, and nutrient intake were analyzed through SPSS multiple logistic regression analysis. In the case of depression, there was a significant effect on the intake of four of the 20 nutrients (water, protein, cholesterol, and vitamin E). When experiencing activity restrictions, the intake of eight of the 20 nutrients (phosphorus, magnesium, vitamin A, vitamin D, beta-carotene, retinol, thiamine, and niacin) was affected. When experiencing chewing discomfort, the intake of three of the 20 nutrients (fat, magnesium, and vitamin E) was affected. Elderly people who suffer from depression, activity restrictions, and discomfort with chewing are at risk of various nutrient deficiencies, and related studies need to be conducted.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.8
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• pp.1116-1124
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• 2005

The influence of fiber content of hay (low-fiber 47% NDF and high-fiber 62% NDF of DM) and concentrate level (high 50% and low 20% of ration DM) on chewing activity, passage rate and nutrient digestibility were tested on four restrict-fed (11.1 to 13.7 kg DM/d) Holstein cows in late lactation. Aspects of ruminal fermentation and digesta particle size distribution were also investigated on two ruminally cannulated (100 mm i.d.) cows of the same group of animals. All digestion parameters studied were more affected by the fiber content of the hay and its ratio to non structural carbohydrates than by the concentrate level. Giving a diet of high-fiber (62% NDF) hay and low concentrate level (20%) increased chewing activity but decreased solid passage rate and total digestibility of nutrients due to a limited availability of fermentable OM in the late cut fiber rich hay. A supplementation of high-fiber hay with 50% concentrate in the diet seems to improve the ruminal digestion of cell contents, whilst a depression of the ruminal fiber digestibility was not completely avoided. Giving a diet of low-fiber (47% NDF) hay and high concentrate level (50%) reduced markedly the chewing and rumination activity, affected negatively the rumen conditions and, consequently, the ruminal digestion of fiber. A reduction of the concentrate level from 50 to 20% in the diet of low-fiber hay improved the rumen conditions as reflected by an increase of the ruminal solid passage rate and of fiber digestibility and in a decrease of the concentration of large particles and of the mean particle size of the rumen digesta and of the faeces. Generally, it can be summarised that, (i) concentrate supplementation is not a strategy to overcome limitations of low quality (fiber-rich) hay, and (ii) increase of the roughage quality is an effective strategy in ruminant nutrition, especially when concentrate availability for ruminants is limited.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.6
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• pp.560-571
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• 2002

Jaw relations and the recording methods have been controversial aspects of dentistry. The purpose of this study was to quantify the relative muscle activity of the masseter and temporal muscles in relation to different intermaxillary relations recorded by intra-oral tracer during maximal clenching and to decide the optimal mandibular position. Ten volunteers with healthy TMJ were studied. Intra-oral tracer was assembled and bite block was fabricated in the articulator. Intra-oral tracer was placed in the mouth, and four mandibular positions were recorded. EMG activity was recorded on a BIO-PAK system (Bio-Research Associates, Inc. USA.) in masseter and temporal muscle and compared in each mandibular positions. The results were as follows: 1. In comparison with maximum intercuspation, the chewing position was the most similar followed by tapping position, myocentric position and posterior border position. However the differences were not statistically significant. 2. In comparison of bilateral symmetry of masseter muscle, tapping position was the most symmetrical followed by chewing position and maximum intercuspation. Myocentric position and posterior border position were not symmetrical. (P<.05). 3. In comparison of bilateral symmetry of anterior temporal muscle, chewing position was the most symmetrical followed by posterior border position, maximum intercuspation, myocentric position and tapping position. However the differences were not statistically significant. 4. In comparison of proportionality of anterior temporal muscle to masseter muscle activity on left side, posterior border position was the greatest followed by myocentric position, taping position, chewing position and maximum intercuspation. And the proportionality of posterior border position was greater than that of maximum intercuspation. (P<.05). 5. In comparison of proportionality of anterior temporal muscle to masseter muscle activity on right side, myocentric position was the greatest followed by posterior border position, tapping position, maximum intercuspation and chewing position. However the differences were not statistically significant.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.2
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• pp.37-52
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• 1989

The purpose of this study was to investigate the relationship between sternocleidomastoid (SCM) and masseter muscles during occlusal functions by means of EMG recordings of examined muscles. For the study, eighteen normal subjects were selected and the Bio-electric Processor EM2 (Myo-tronics Research, Inc., U.S.A.) with the surface electrodes was used to record the EMG activity from the right and left middle of masseter and insertion of SCM of each subject during right and left gum-chewing and isometric contraction by changing the biting force at right eccentric position of jaw. The amount of biting force ranged from 5 to 70kg during isometric contraction were measured by use of Jaw Force Meter. (Nihon Koden Kogyo, Japan.) The results were as follows: 1. The activity onset of SCM and masseter on the same side was almost at the same time, and integrated EMG values of two muscles on the chewing side were higher than the same named muscles on the non-chewing side during gum-chewing. (p<0.01) 2. The regression correlation was not present between both masseters (p>0.05), but between both SCM muscles or muscles of two kinds on the chewing or non-chewing side. ($p{\leqq}0.05$) 3. The integrated EMG value of SCM on chewing or non-chewing side were about 10 percent of that of ipsilateral masseter. 4. Mean voltage of each examined muscles were almost proportional to biting force during isometric contraction and the slope of voltage/biting force line was steepest at the ipsilateral masseter, followed by contalateral masseter, ipsi- and contra-lateral SCM muscles. 5. Mean voltage of ipsilateral masseter was highest during isometric contraction, followed by ipsilateral masseter, contra- and ipsi-lateral SCM muscles.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.4
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• pp.718-730
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• 1995

This study was performed to measure the mandibular movement and the changes of masicatory and sternocleidomastoid muscle activity reflected by occlusal disturbance during habitual chewing. For this study, 18 subjects(14 males and 4 females with an average age of 24.0) were selected. The impression of each subject were taken for measuring intermolar distance on lower dentition. The activities of masticatory and sternocleidomastoid muscle and the mandibular movement were recorded and analyzed during habitual chewing by means of E.M.G.(electromyograph), E.G.N.(electrognathograph), rotate program in BioPak analyzing system(BioResearch Inc.). The results were as follows : 1. In EMG of the mandibular rest position, the mean value of muscle activites were increased by nocleidomastoid muscle and anterior belly of digastric muscle(0.05

• The Journal of Advanced Prosthodontics
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• v.8 no.3
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• pp.187-193
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• 2016

PURPOSE. This pilot study was to find the influence of complete denture on the brain activity and cognitive function of edentulous patients measured through Electroencephalogram (EEG) signals. MATERIALS AND METHODS. The study recruited 20 patients aged from 50 to 60 years requiring complete dentures with inclusion and exclusion criteria. The brain function and cognitive function were analyzed with a mental state questionnaire and a 15-minute analysis of power spectral density of EEG alpha waves. The analysis included edentulous phase and post denture insertion adaptive phase, each done before and after chewing. The results obtained were statistically evaluated. RESULTS. Power Spectral Density (PSD) values increased from edentulous phase to post denture insertion adaption phase. The data were grouped as edentulous phase before chewing (EEG p1-0.0064), edentulous phase after chewing (EEG p2-0.0073), post denture insertion adaptive phase before chewing (EEG p3-0.0077), and post denture insertion adaptive phase after chewing (EEG p4-0.0096). The acquired values were statistically analyzed using paired t-test, which showed statistically significant results (P<.05). CONCLUSION. This pilot study showed functional improvement in brain function of edentulous patients with complete dentures rehabilitation.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.7
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• pp.960-964
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• 2014

An experiment was conducted to determine the effects of diets containing coarse-texture rice straw and small particle size alfalfa pellets as a part of total mixed ration (TMR) on milk productivity and chewing activity in lactating dairy cows. Sixteen multiparous Holstein dairy cows ($670{\pm}21kg$ body weight) in mid-lactation ($194.1{\pm}13.6$ days in milk) were randomly assigned to TMR containing 50% of timothy hay (TH) or TMR containing 20% of rice straw and 30% of alfalfa pellet mixture (RSAP). Geometric mean lengths of TH and RSAP were found to be 5.8 and 3.6, respectively. Dry matter intake, milk yield and milk composition were measured. Moreover, eating and ruminating times were recorded continuously using infrared digital camcorders. Milk yield and milk composition were not detected to have significant differences between TH and RSAP. Dry matter intake (DMI) did not significantly differ for cows fed with TH or RSAP. Although particle size of TH was larger than RSAP, eating, ruminating and total chewing time (min/d or min/kg of DMI) on TH and RSAP were similar. Taken together, our results suggest that using a proper amount of coarse-texture rice straw with high value nutritive alfalfa pellets may stimulate chewing activity in dairy cows without decreasing milk yield and composition even though the quantity of rice straw was 40% of TH.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.389-423
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• 1998

This investigation was designed to determine the effectiveness of the posterior occlusal schemes on masticatory activity during mastication in complete denture. Twelve edentulous subjects were selected for this study. All subjects had no past history and no functional abnormality on masticatory system and TMjoint. And, they had residual ridge of favorable morphology, firm mucosa and Class I skeletal jaw relationship, Twelve experimental denture with interchangeable occlusions(0-degree teeth, 30-degree teeth, Levin teeth and S-A teeth) were constructed for this study. The masticatory performance was analyzed by means of standard sieve(10, 16, 20, 30sieve), and the electrical activity from selected muscles(Temporalis and Masseter muscle) was recorded simultaneously with electromyography (Bio-Pak system) as the subject masticated test foods (rice, peanut and gum) with four different occlusal schemes. Mandibular movement was, also, measured with Sirognathography(Bio-Pak system). These recordings were performed in immediately, after 1 week and after 2 weeks of insertion of complete denture. The results were as fellows; 1. The average masticatory performance of 0-degree artificial teeth was higher than any other artificial teeth. 2. Masticatory performance in denture wearer was affected preferentially by food and artificial occlusal schemes. 3. During chewing, there was a statistical difference of EMG activity between masseter and temporal muscle(p<0.01). Especially, EMG activity of working masticatory muscle was highly affected by food rather than by artificial occlusal schemes. 4. In denture wearer, the velocity of opening was not affected by food, whereas, the velocity of closing was faster in soft food chewing than in hard food chewing, and the amount of vertical displacement was grater in chewing of soft and large bolus than in chewing of hard and small bolus. However, the amount of lateral displacement showed conversely(p<0.05). 5. It was considered that masticatory performance in denture wearer is not affected by the condition of residual ridge. the history of denture wear, the preference, the adaptation to artificial teeth and the total mesiodistal length of artificial posterior teeth.