Psychological stress-relieving effects of chewing - Relationship between masticatory function-related factors and stress-relieving effects

Influence of Chewing Gummy Jelly Containing Aroma Compound on Psychological Stress and Autonomic Nervous System Activity: A Randomized Crossover Trial

The aim of this randomized crossover trial was to clarify the effects of chewing gummy jelly containing a compound of decanoic acid, oligonol, methyl cellulose, and citral (DOMAC) on mental stress and autonomic nervous activity in facemask wearers. A placebo gummy jelly was used in conjunction with DOMAC. Eight healthy adults with no tooth loss (mean age: 35±5 yr) were included. The participants were required to chew one DOMAC or placebo gummy jelly for 5 min after wearing a facemask for 20 min in the laboratory, then the other gummy jelly after a washout period. Rate of change in salivary immunoglobulin A (IgA) as a marker of stress was compared between before and after chewing. Additionally, sympathetic and parasympathetic activity was compared at both time points. A significant difference was observed in the percentage change in salivary IgA from that at before wearing a facemask: 127±34% (mean±standard deviation) while wearing a facemask; 46±20% while chewing DOMAC gummies; and 47±26% while chewing placebo gummies (p<0.05). Parasympathetic nervous system activity was 971.2±1040.7 ms2 at 20 min after facemask wearing; 295.0±253.0 ms2 after DOMAC gummy chewing; and 1956.1±2798.0 ms2 after chewing a placebo gummy jelly; with significant differences only being found between 20 min after facemask wearing and after DOMAC gummy chewing (p<0.05). Sympathetic nervous system activity was 1.80±1.83 at 20 min after facemask wearing; 4.06±3.33 after DOMAC gummy chewing; and 4.95±7.02 after chewing a placebo gummy jelly; with significant differences only being found between 20 min after facemask wearing and after DOMAC gummy chewing. These results suggest that chewing gummy jellies containing DOMAC relieves stress caused by facemask wearing and activates sympathetic nervous system activity.

White matter abnormalities mediate the association between masticatory dysfunction and cognition among older adults

BACKGROUND

Masticatory parameters, such as reduced number of teeth and posterior contacts, have been shown to be associated with reduced cognitive status. The underlying mechanisms that affect these associations, are however, not well understood.

OBJECTIVES

The study aims to investigate the association between masticatory dysfunction and cognition and explore the mediating effect of brain structure.

METHODS

In this cross-sectional study, 45 older adults with subjective masticatory dysfunction (mean age 72.3 ± 4.0 years) were included. Mini-Mental State Examination score <25, brain trauma, neurological disease, neurodegenerative disorders, depression or poor Swedish language skills were criteria for exclusion. Cognitive functions (executive function and episodic memory) and masticatory dysfunction defined by functional occluding status (FOS; the number of occluding units and number of remaining teeth) were analysed with partial correlation models. Structural magnetic resonance imaging was performed on 28 feasible participants. Multiple regression analyses were performed to evaluate the predictive value of brain structure and white matter hypointensities (WM-hypo) on cognitive functions. A mediation analysis was applied to assess significant predictor/s of the association between FOS and cognition.

RESULTS

Both episodic memory and executive functions were positively correlated with FOS. WM-hypo predicted cognitive status (executive function, p ≤ .01). WM-hypo mediated 66.6% (p = 0.06) of the association between FOS and executive functions.

CONCLUSION

Associations between FOS and cognitive functions are reported, where FOS, a potential modifiable risk factor, was related to both episodic memory and executive functions. The mediating effect of WM-hypo on the association between FOS and executive functions highlights the impact of the vascularisation of the brain on the link between mastication and cognition. The present study provides increased knowledge that bridges the gap between masticatory dysfunction and cognition.

Effects of medical and nursing group rounds combined with emotional nursing on quality of life and emotion in patients with malignant lymphoma

To investigate the effects of medical and nursing visits in the same group combined with emotional care on the quality of life and emotions of patients with malignant lymphoma. One hundred sixty cases of malignant lymphoma patients admitted to our hospital from March 2020 to July 2022 were selected as retrospective study subjects and divided into 80 cases each in the control group and the observation group according to the different nursing methods. Among them, the control group implemented conventional emotional care, and the observation group implemented medical and nursing visits in the same group on the basis of the control group. The differences in quality of life, anxiety-related scores and sleep quality between the 2 groups of patients with malignant lymphoma before and after nursing were compared. After nursing, the mental vitality (P = .015), social interaction (P < .001), emotional restriction (P = .007), and mental status (P = .028) scores of patients in the observation group were higher than those in the control group. After nursing, the Self-Rating Anxiety Scale (P < .001) and Hamilton Anxiety Scale (P < .001) of malignant lymphoma patients in the observation group were significantly lower than those in the control group, and the sleep quality (P < .001), increased awakening (P < .001), sleep disturbance (P < .001), night terrors (P < .001) scores in the observation group were significantly lower than those in the control group. The combination of medical and nursing group checkups and emotional care can effectively improve the quality of life and sleep of patients with malignant lymphoma and reduce adverse emotions, which is beneficial to patient prognosis and clinical treatment. It has certain reference value for the care of patients with malignant lymphoma.

Psychological Stress as a Determinant of Increased Maximum Voluntary Bite Force - A Clinical Observational Study

Background Psychological stress is a known risk factor and modulator for several oral diseases. It is among the critical etiological factors of bruxism and several other disorders. The quantum of bite force is one of the prime determinants of wear resistance and the clinical performance of restorations. Thus, the present study aims to investigate the relationship between the maximum voluntary bite force (MVBF) and the amount of perceived stress experienced by an individual.  Materials and methods Patients (n=111) fulfilling the exclusion and inclusion criteria were divided into high, medium, and low-stress groups based on their stress scores deduced from the Perceived Stress Scale questionnaire (PSS). Bite force measurement was recorded in Newtons (N) for each subject using a portable customized bite recording FlexiForce sensor (B 201). The data were analyzed using Kruskal-Wallis and independent samples t-test. Results  Among the females, the bite force in the medium and high-stress groups was greater compared to the low-stress level group. On the other hand, there was no difference in bite force between any of the stress level groups among male participants.  Conclusion The results show that higher MVBF is associated with higher perceived stress scores in adult females. Practical Implications Psychological counseling can be included in the dental treatment plan of individuals with a high-stress score to counteract their stress-related higher occlusal forces, parafunctional jaw movements, and risky oral health behaviors, thereby potentially reducing the incidence of adverse outcomes such as temporomandibular joint dysfunction and restoration failure by careful choice of restorative materials.

Relationship between age and occlusal force in adults with natural dentition

This study aimed to clarify the relationship between age and occlusal force in adults with natural dentition. A total of 385 adults (180 males and 205 females) with natural dentition participated in this study. Subjects were asked to perform maximum clenching for approximately 3 s, and the occlusal forces on both sides and habitual chewing side were calculated using a dental prescale. Regression analysis was performed by sex with occlusal forces on both sides and habitual chewing side as the dependent variable and age as the independent variable. In addition, all subjects were divided into three groups: young group (20-39 years), middle group (40-59 years), and old group (60 years and over), and the occlusal forces on both sides and habitual chewing side were compared among the three groups. The occlusal forces did not differ from 20 to 60 years old for both males and females, and the occlusal forces gradually decreased after 60 years old. The curve of the polynomial equation was the most suitable. The occlusal forces on both sides and the habitual chewing side were similar in the young and middle groups, and the values of the old group were significantly smaller than those of the other two groups. From these results, it was suggested that the occlusal force of adults with natural dentition does not differ from 20 to 60 years old and can be represented by a curve of a cubic polynomial, and it significantly decreases after 60 years old.

Eating habit patterns may predict maximum occlusal force: A preliminary study

Masticatory function is thought to be related to various eating habits, but it is difficult to evaluate overall masticatory function by assessing complex eating habits. Maximum occlusal force is an important indicator of masticatory function that is affected by age and sex. This preliminary study focused on the maximum occlusal force of young women and their eating habits, excluding food and nutritional factors, and investigated whether individual eating habits and eating habit patterns predict maximum occlusal force. We measured the maximum occlusal force for the whole dentition of 53 healthy young women before they ate lunch. The participants also completed a 12-item questionnaire about their eating habits. Scores were determined from the relationship between each item and increased maximum occlusal force. We found a significant but weak relationship between maximum occlusal force and some questions. The total questionnaire scores for the participants’ eating habits showed an almost normal distribution (mean ± standard deviation: 22.7 ± 2.6, median: 23.0, mode: 23.0, range of total scores: 17–28). The accuracy of the linear regression between the total scores for eating habits and maximum occlusal force was high but not perfect (β: standardized regression coefficient = 0.527, P < 0.001). Although further research is needed, our findings confirm that eating habit patterns are significantly associated with maximum occlusal force and may help predict occlusal force. Our results provide important information about eating patterns in humans.

Reference value of masticatory performance by measuring the amount of glucose extraction from chewing gummy jelly

PURPOSE

The purpose of this study was to determine a reference value for masticatory performance (MP) by measuring the amount of glucose extracted(AGE) from chewing gummy jelly.

METHODS

A total of 237 young adults (young group, 20-39 years), 147 middle-aged adults (middle-aged group, 40-59 years), and 177 older adults (old group, 60-87 years) participated in this study. All participants had natural dentition, excluding the third molars. AGE was measured when the participant chewed gummy jelly and used as a parameter of MP. AGE was compared among the three groups. Next, AGE in each group was compared between the habitual chewing side and non-habitual chewing side, and between males and females. The correlation between age and AGE was also investigated.

RESULTS

AGE in the young, middle, and old groups were similar, and no significant differences were observed. AGE was significantly higher in the habitual chewing side compared to the non-habitual chewing side, and in males than that in females. No significant correlations were found between age and AGE. AGE in the habitual chewing side of all ages was 221.9 ± 34.4 mg/dL for males and 206.0 ± 28.7 mg/dL for females. The mean-2SD (standard deviation) value representing the reference value of healthy adults was 153.1 mg/dL for males and 148.6 mg/dL for females, which was close to 150 mg/dL.

CONCLUSION

It was concluded that the reference value of masticatory performance as measured by the amount of glucose extraction after chewing gummy jelly was 150 mg/dL.

Neurotic personality trait as a predictor in the prognosis of composite restorations: A 24-month clinical follow up study

The role of personality traits in modulating the incidence and progression of medical disease conditions are well documented, however, there is a paucity of information for its effects on dental health conditions and specifically on the prognosis of restorative dental materials. This study aims to evaluate the clinical performance of Micro-hybrid and Nano-ceramic composite restorations among patients with different personality traits. A total of 323 patients, indicated to receive operative treatment at a University Dental College Hospital, were invited to participate in this study. Consenting patients were requested to complete the Big Five Inventory (BFI-44 Item) personality questionnaire and were evaluated by a psychiatrist for categorizing the participants based on their personality traits. Out of the recruited patients, 124 patients falling in to the dominant trait of Agreeableness (n = 62) and Neuroticism (n = 62) were included in the study for further investigation. Next, patients from the Agreeableness (Group A) and the Neuroticism personality trait group (Group N) were randomly divided into two subgroups each—sub group Am (n = 44) and Nm (n = 48) for Micro-hybrid composite restorations and Sub group An (n = 42) and Nn (n = 47) for Nano-ceramic composite restorations. Two trained and calibrated dentists prepared the cavities according to previously published methodology. The restorations were evaluated at baseline (immediately after restoration), 6-months, 12-months and 24-months intervals by two blinded independent dental professionals for anatomical form, secondary caries, color match, retention, marginal adaptation, surface texture, marginal discoloration and post-operative sensitivity. There is no statistically significant difference noted in various parameters of restoration performance between Micro-hybrid composite and Nano-ceramic composite compared among ‘agreeableness’ personality group and among ‘neuroticism’ personality group after controlling the personality trait factor. Higher ‘Neuroticism’ individuals had higher restoration deterioration in color matching and surface texture when compared to higher ‘Agreeableness’ trait individuals. Regression analysis showed no effect of gender or cavity size on the outcome of results. Assessment of personality traits may serve as a useful tool during treatment planning which would aid clinicians in choosing suitable restorative dental material and prosthesis design according to individual patient’s physiological and functional needs, thereby overall improving the quality of treatment provided.

Effects of stress on chewing and food intake in patients with anorexia nervosa

OBJECTIVE

The present study investigates the impact of psychosocial stress on chewing and eating behavior in patients with anorexia nervosa (P_AN ).

METHOD

The eating and chewing behavior of P_AN were examined in a standardized setting by means of a chewing sensor. These procedures encompassed n = 19 P_AN , age, and gender matched to n = 19 healthy controls (HC). Food intake and chewing frequency were assessed in two experimental conditions: rest versus stress (via Trier Social Stress Test). To verify stress induction, two appraisal scales were employed. In addition, chronic stress, psychological distress and eating disorder symptoms were assessed.

RESULTS

In terms of food intake and chewing frequency, the results of the 2x2 ANOVA demonstrated a significant effect of condition and group. During stress, all participants demonstrated a higher chewing frequency and a decreased ingestion. In general, patients ate less at a lower chewing frequency (vs. HC). However, sample specific analyses demonstrated that the eating and chewing behavior of P_AN remained unchanged regardless of the condition, except for their drinking. Food choices were comparable between the groups, but appetite values significantly differed.

DISCUSSION

The increase in chewing frequency in all participants during stress suggests that chewing might impact affect regulation, however, not specifically in P_AN . Future research should clarify to what extent the normalization of chewing behavior could ameliorate ED-symptoms (incl. food intake) in P_AN . The application of a chewing sensor could support this aim and future interventions.

Chewing Behavior Attenuates the Tumor Progression-Enhancing Effects of Psychological Stress in a Breast Cancer Model Mouse

We examined whether chewing behavior affects the tumor progression-enhancing impact of psychological stress. Human breast cancer cell line (MDA-MB-231) cells were inoculated into the mammary fat pads of athymic nude mice. The mice were assigned randomly to control, stress, and stress+chewing groups. Psychological stress was created by keeping mice in a transparent restraint cylinder for 45 min, three times a day, for 35 days after cell inoculation. Animals in the stress+chewing group were provided with a wooden stick for chewing on during the psychological stress period. Chewing behavior remarkably inhibited the tumor growth accelerated by the psychological stress. Immunohistochemical and Western blot findings revealed that chewing behavior during psychological stress markedly suppressed tumor angiogenesis and cell proliferation. In addition, chewing behavior decreased serum glucocorticoid levels and expressions of glucocorticoid and β2-adrenergic receptors in tumors. Chewing behavior decreased expressions of inducible nitric oxide synthase and 4-hydroxynonenal, and increased expression of superoxide dismutase 2 in tumors. Our findings suggest that chewing behavior could ameliorate the enhancing effects of psychological stress on the progression of breast cancer, at least partially, through modulating stress hormones and their receptors, and the subsequent signaling pathways involving reactive oxygen and nitrogen species.

Evaluation of occlusal force and masticatory performance in elderly adults with natural dentition unaffected by occlusal support

PURPOSE

This study aimed to clarify whether occlusal force and masticatory performance reduced in elderly adults and whether these parameters were affected by age.

METHODS

Seventy-eight elderly adults (elderly group) and 76 young adults (control group) with natural dentition were asked to maximally clench for 3 s, and occlusal force was calculated. The amount of glucose extraction after chewing a gummy jelly was measured as the parameter for masticatory performance. Occlusal force and masticatory performance were compared between the elderly and control groups. The correlation between age and occlusal force and between age and masticatory performance was also investigated.

RESULTS

Occlusal force was significantly smaller in the elderly group (P < 0.05). Masticatory performance was lower in the elderly group, but this difference was not statistically significant. No significant correlation was observed between age and occlusal force in the control group, but a negative correlation was found in the elderly group (P < 0.05). No significant correlation was found between age and masticatory performance in either group.

CONCLUSION

Occlusal force was affected by age and reduced significantly, whereas masticatory performance was not affected by age and was maintained in elderly adults.

Influence of Neuroticism on the Prognosis of Nanoceramic and Microhybrid Composite Restoration: A Comparative 1-year Clinical Study

AIM

This study aimed to compare the clinical performance of nanoceramic and microhybrid-based composite restorations in adult patients with different personality traits.

MATERIALS AND METHODS

Patients in accordance with the inclusion and exclusion criteria were asked to complete the BFI (Big Five Inventory) questionnaire. Of a total of 323 patients, 124 (67 males and 57 females) patients were categorized into agreeableness and neuroticism traits and were included in the study. The patients were randomly divided into two subgroups: SG I A (n = 31) and II A (n = 31) for microhybrid composite (Spectrum TPH 3, Dentsply/DeTrey, Konstanz, Germany), SG I B (n = 31) and II B (n = 32) for nanoceramic composite restorations (Ceram X mono, Dentsply/DeTrey, Germany). At baseline, 6 and 12 months, the restorations were evaluated using the Modified USPHS (United States Public Health Service) evaluation criteria. The Pearson chi-square and the Fisher's exact test were used to assess the difference between the personality traits and restorative material groups where a probability value of P < 0.05 was considered to be statistically significant.

RESULT

Most of the restorations scored alfa (A), whereas very few scored bravo (B) in all the subgroups. However, there were no charlie (C) or delta (D) scores. Overall, Spectrum TPH and Ceram x mono displayed superior performances in retention and postoperative sensitivity than all the other clinical parameters. Furthermore, Ceram x mono restorations showed more surface roughness than Spectrum TPH. No statistical differences in the restoration performance were found between both personalities and restorative material types.

CONCLUSION

Although neuroticism has an effect on various health outcomes, its impact on the clinical performance of composite restorations during the follow-up period was not observed. In addition, there was no difference between the performance of nanohybrid and microhybrid composite.

Association between Chewing Problems and Sleep among Japanese Adults

An association between physical illness and sleep has been suggested. Disordered chewing might be a physical factor that is associated with sleep issues. This cross-sectional study aimed to determine whether chewing problems are associated with sleep in Japanese adults. Sleep and chewing issues were evaluated in 6,025 community residents using a self-reported questionnaire. The prevalence of poor sleep quality and sleeping for <6 h/day (short duration) were 15.6% and 29.4%, respectively. Multivariate logistic regression analyses showed that prevalence of poor sleep quality was significantly associated with self-reported medical history (odds ratio (OR), 1.30; p < 0.001), self-reported symptoms (OR, 4.59; p < 0.001), chewing problems (OR, 1.65; p < 0.001), and poor glycemic control (OR, 1.43; p=0.035). The prevalence of short sleep duration was also significantly associated with female sex (OR, 1.23; p=0.001), self-reported symptoms (OR, 1.60; p < 0.001), chewing problems (OR, 1.30; p=0.001), and being overweight (OR, 1.41; p < 0.001). In conclusion, chewing problems were associated with poor sleep quality and short sleep duration among Japanese adults.

Comparative Evaluation of Marginal Adaptation and Fracture Strength of Different Ceramic Inlays Produced by CEREC Omnicam and Heat-Pressed Technique

Objective

The aim of this in vitro study was to evaluate marginal adaptation and fracture strength of inlays produced by CEREC Omnicam using different types of blocs and heat-pressed technique. Methods: Seventy-five extracted human mandibular molars were divided randomly into 5 groups (n=15). 60 molars in four groups received MOD inlay preparations. Experimental groups were CO: Intact teeth, EC: IPS e.max CAD and CEREC, LU: Lava Ultimate and CEREC, EL: IPS Empress CAD and CEREC, EP: IPS Empress Esthetic ingots and heat-pressed technique. Marginal gap measurements were taken with a stereomicroscope. Restorations were cemented with Variolink N and stored in distilled water at 37°C for 24 hours. All samples were subjected to thermocycling. The fracture strength of specimens was determined at a 0.5 mm/min crosshead speed until fracture. Fracture modes were determined. Statistical analyses were performed using one-way analysis of variance for fracture strength data and Kruskal–Wallis for marginal gap data (p=0.05).

Results

The mean marginal gap size of EC, LU, EL, and EP were 33.54 µm, 33.77 µm, 34.23 µm, and 85.34 µm, respectively. EP had statistically higher values than other groups. The fracture strength values were significantly higher in the intact teeth group (3959,00 ± 1279,79 N) than those of restored groups EC (2408,00 ± 607,97 N), LU (2206,73 ± 675,16), EL (2573.27 ± 644,73) ve EP (2879,53 ± 897,30).

Conclusion

Inlays fabricated using CEREC Omnicam demonstrated better marginal adaptation than inlays produced with heat-pressed technique, whereas fracture strength values of inlays fabricated with different type of blocks using CEREC Omnicam exhibited similarity to those fabricated with heat-pressed technique.