Actual state of the diurnal masseteric electromyogram: Differences between awareness and non-awareness of awake bruxism.

Purpose: This study aimed to elucidate the relationship between diurnal masseter muscle activity and awareness of diurnal awake bruxism (d-AB) by conducting a comparative analysis of electromyographic (EMG) data from individuals with and without awareness of diurnal awake bruxism (d-AB), utilizing EMG data gathered from multiple subjects.

Methods: Unilateral masseter electromyography (EMG) recordings were performed during the daytime using an ultraminiature wearable EMG device. A total of 119 participants (59 with awareness of diurnal tooth clenching [d-TC] and 60 without awareness of d-TC) were included.

Masticatory performance with one missing molar.

Purpose: This study aimed to evaluate masticatory performance in cases where one molar was missing.

Methods: Participants were 156 adults with one molar missing from their natural teeth, who were divided into group A (without prosthetic treatment) and group B (with prosthetic treatment). The non-missing side was designated as A1 or B1, and the missing side was designated as A2 or B2.

Usefulness of the masticatory score by occlusal support.

This study aimed to clarify the usefulness of masticatory score by occlusal support. A total of 605 adults were classified into four groups (A1, A2A3, B, and C) according to the Eichner classification, and the relationship between the amount of glucose eluted and masticatory score was investigated in each group. A significant correlation between the glucose eluted and masticatory score was observed in groups A2A3, B, and C, but not in A1, suggesting that the masticatory score is useful for evaluating the masticatory performance of complete denture wearers, but not adults with natural dentition.

Path pattern and movement during mastication on habitual and non-habitual chewing sides.

Purpose: To clarify the presence or absence of differences in path pattern and movement during mastication between the habitual and non-habitual chewing sides.

Methods: Participants were 225 healthy adults with natural dentition. Mandibular movement while chewing gummy jelly on each side was recorded, and masticatory path pattern was classified into five types (one normal and four abnormal).

Validity of analysis of masticatory movement using a two-dimensional mandibular movement recording device.

To clarify the validity of analysis of masticatory movement using a two-dimensional (2D) mandibular movement recording device, masticatory movements (pattern of movement path, opening distance, masticatory width, and cycle time) were compared between simultaneous recordings made by 2D and three-dimensional (3D) devices in healthy adults. The 2D device can perform the same level of mandibular movement analysis as the 3D device if the distance between LED and camera is fixed (15 cm), and the findings indicated the suitability of the 2D device for clinical application.

Relationships of physical constitution with occlusal force and masticatory performance in adults with natural dentition.

This study aimed to clarify whether physical constitution affects masticatory function. A total of 251 healthy adults with completely natural dentition participated in this study. Height, weight, and body mass index (BMI) were used as parameters representing physical constitution, and the amount of glucose eluted from chewed gummy jelly and maximum occlusal force was used as parameter representing masticatory function.

Usefulness of newly devised food intake score in removable denture wearers.

Background: Although the food intake score (FIS) from conventional food intake questionnaires is widely used, the evaluation method, number of foods and food selection used in the questionnaire can be improved.

Objective: This study aimed to evaluate the usefulness of a newly devised FIS in removable denture wearers.

Methods: A total of 219 removable denture wearers were asked about their food intake, and three types of FIS (FIS1, FIS2 and FIS3) were calculated as subjective parameters.

Masticatory path pattern and masticatory performance while chewing gummy jelly.

The purpose of this study was to clarify masticatory path pattern and masticatory performance during gummy jelly chewing. A total of 235 healthy adults were asked to chew gummy jelly for 20 s on each side, and the masticatory movement was recorded using a Motion Visi-Trainer (MVT V1). Next, the amount of glucose extraction was measured as a parameter of masticatory performance.

Evaluation of automatic cleaning in analysis of occlusal force.

This study aimed to clarify the usefulness of automatic cleaning in analysis of occlusal force. The maximum occlusal force was calculated in 151 healthy adults before cleaning (B), after manual cleaning (M), and after automatic cleaning (A) and compared among the three conditions. The absolute value of the error rate of A, based on M, was calculated.

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.

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 extraction (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.

Stability of masticatory movements after placement of implant-supported denture.

The purpose of this study was to clarify the stability of masticatory movement after placement of implant-supported denture. Fourteen patients (patient group) with mandibular implants denture and maxillary complete denture and 30 dentate adults (control group) were asked to chew a boiled fishpaste, and the masticatory movement was recorded using MKG. For the 10 cycles beginning with the 5th cycle of mastication, the parameters representing the stability of masticatory movement were calculated.

Inter-measurement variation of masticatory performance test using gummy jelly.

The purpose of this study was to clarify the inter-measurement variation of the masticatory performance test. Forty healthy adults were divided into group A (10 males and 10 females), who did not chew the test food before experiment, and group B (10 males and 10 females) who chewed the test food before the experiment. Subjects were asked to chew a gummy jelly for 20 s on the habitual chewing side, and the amount of glucose extraction was measured.

Gender differences in masticatory function in elderly adults with natural dentition.

The purpose of this study was to clarify the presence or absence of gender differences in masticatory function in elderly adults with completely natural dentition. Fifty-six elderly adults aged 65 years and older (elderly group) and 60 young adults in their 20-40 s (young group) with natural dentition participated in this study. The maximum occlusal force on the habitual chewing side was measured using dental prescale.

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.

Comparison of two dental prescale systems used for the measurement of occlusal force.

The purpose of this study was to clarify the relationship between two types of dental prescale systems. Forty healthy subjects were asked to maximally clench for about 3 s, and the maximum occlusal force before and after cleaning was calculated using an Occluzer FPD707 for dental prescale (P1) and a bite force analyzing system for dental prescale II (P2). The maximum occlusal forces measured by P1 and P2 were compared before cleaning and after cleaning.

Effect of denture treatment on masticatory movement in patients with complete dentures.

Purpose: To clarify the effect of denture treatment on masticatory movement in patients with complete dentures.

Methods: Forty eight patients who required new complete dentures and 20 patients who were satisfied with their original complete dentures (control: C group) participated in this study. Subjects were asked to chew a gummy jelly on their habitual chewing side.

Masticatory performance and oral health-related quality of life before and after complete denture treatment.

Purpose: To clarify the relationship between masticatory performance and oral health-related quality of life (OHRQoL) before and after complete denture treatment.

Methods: Thirty patients wearing complete dentures were asked to chew a gummy jelly on their habitual chewing side, and the amount of glucose extraction during chewing was measured as the parameter of masticatory performance. Subjects were asked to answer the Oral Health Impact Profile (OHIP-J49) questionnaire, which consists of 49 questions related to oral problems.

Masticatory performance of the elderly as seen from differences in occlusal support of residual teeth.

Purpose: To clarify whether the occlusal state affects the masticatory performance of elderly adults.

Methods: Elderly women were asked to chew a gummy jelly, and the amount of glucose extraction was measured as the parameter for masticatory performance. Subjects were divided into five groups depending on occlusal support on the habitual chewing side (G1: no occlusal support of posterior teeth, G2: occlusal support of first premolar, G3: occlusal support of premolars, G4: occlusal support from first premolar to first molar, and G5: occlusal support from first premolar to second molar).

Effect of the bitterness of food on muscular activity and masticatory movement.

Purpose: The purpose of this study was to clarify the effect of the bitterness of food on muscular activity and masticatory movement.

Methods: Twenty healthy subjects were asked to chew a non-bitter gummy jelly and a bitter gummy jelly on their habitual chewing side. The masseter muscular activity and the movement of mandibular incisal point were recorded simultaneously.

Relationship between masticatory performance using a gummy jelly and masticatory movement.

Purpose: The purpose of this study was to clarify the relationship between masticatory performance using a gummy jelly and masticatory movement.

Methods: Thirty healthy males were asked to chew a gummy jelly on their habitual chewing side for 20s, and the parameters of masticatory performance and masticatory movement were calculated as follows. For evaluating the masticatory performance, the amount of glucose extraction during chewing of a gummy jelly was measured.

Changes in mandibular movement during chewing of different hardness foods.

In order to clarify the change in mandibular movement during chewing of foods with different hardness, 20 healthy subjects were asked to chew 3 types of gummy jellies (containing 6, 8, and 10% gelatin), and the masseter muscular activity and the mandibular movement were recorded. The indicators representing the muscular activity (integral value of masseter muscular activity), the mandibular movement (opening distance, masticatory width, cycle time, opening maximum velocity and closing maximum velocity), and the stability of masticatory movement were calculated, respectively, and compared among the three foods. The integral value of masseter muscular activity was smallest for the 6% gelatin and significantly increased in order as the content of gelatin increased to 8, 10%.

Relationship between masticatory performance using a gummy jelly and food intake ability in Japanese complete denture wearers.

Twenty patients wearing complete dentures were asked to chew a gummy jelly, and their glucose extraction was measured. Two types of masticatory scores (MS1 and MS2) were calculated using a food intake questionnaire. The relationship between masticatory scores and glucose extraction was investigated.

Gender differences in masticatory movement path and rhythm in dentate adults.

Purpose: The purpose of this study was to clarify whether there might be a gender difference in masticatory movement path and rhythm in dentate adults.

Methods: Thirty healthy males and 30 healthy females were asked to chew softened chewing gum on their habitual chewing side for 20 sec, and the movement of the mandibular incisal point was recorded using mandibular kinesiograph. For 10 cycles from the fifth cycle, the spatial and temporal parameters (spatial: amounts of vertical and lateral movements; temporal: opening, closing, occluding, and cycle times) of masticatory movement path and rhythm and the parameters representing the stability of masticatory movement path and rhythm were calculated and compared between males and females.

Gender difference in masticatory performance in dentate adults.

Purpose: To clarify whether there might be a gender difference in masticatory performance in dentate adults.

Methods: Thirty male subjects and thirty female subjects were asked to chew gummy jelly on their habitual chewing side for 10, 15 and 20s and the amounts of glucose extraction were measured. The changes of both glucose extraction and standardized glucose extraction from 10 to 20s were investigated differently for males and females.