Oral Function for Diagnosing Oral Hypofunction in Healthy Young Adults: A Comparison with the Literature.

This study investigated decline in oral function in healthy young adults and compared it with that observed in an earlier studies employing older adults. The participants comprised 130 young healthy adults (mean age 24.1±2.9 yr), all with complete dentition. All participants underwent the oral hypofunction test established by the Japanese Society of Gerodontology, which evaluates oral hygiene, oral dryness, occlusal force, tongue-lip motor function (oral diadochokinetic rate; ODK), tongue pressure, and masticatory and swallowing function. The average value for and rate of hypofunction of each parameter were calculated. In healthy young adults, the scores were 28.9±17.1% for oral hygiene; 28.8±2.2 for oral dryness; 959.9±499.8 N for occlusal force; 7.0±0.8 times/sec for ODK /pa/, 7.6±0.8 times/sec for /ta/, and 6.9±0.9 times/sec for /ka/; 41.8±8.4 kPa for tongue pressure; 249.8±94.1 mg/dl for masticatory function; and 0.2±0.7 for swallowing function. No sign or symptom of change in oral function was observed at a high rate in young adults. Occlusal force, tongue-lip motor function, and tongue pressure showed a large difference in the rate of hypofunction between younger and older adults, however.

Maxillary Obturator Prosthesis Made with Polyetherketoneketone Using Optical Impression and CAD/CAM System.

This report describes the case of a 68-year-old man who visited our department complaining of poor denture retention and difficulty masticating due to damage to the retainer of a maxillary obturator. The patient had never been satisfied with the fit of this prosthesis, which had been placed two years earlier. The obturator and the mucosal surface of the denture base were incompatible, which had caused the retainer to detach. The maxillary defect was categorized as H3S0D0T0 according to the HS classification. The diagnosis was a masticatory disorder due to a damaged retainer and an incompatible denture base. Optical impressions and occlusal records were taken and a maxillary obturator fabricated using a CAD/CAM system. Dental CAD software was used to design and complete the tooth arrangement. The CAM system was used to mill a polyetherketoneketone disc based on the obtained data and composite resin used to face the teeth and gingiva. The maxillary obturator was placed after only three visits, spanning from impression taking to denture completion. The use of digital data allowed the time to denture completion to be shortened in addition to the number of hospital visits to be reduced. Compared to conventional impression taking, optical impressions also prevent discomfort, decreasing stress for the patient.

Oral function is associated with the body and muscle mass indices of middle-aged dental patients.

OBJECTIVES: Undernutrition is associated with frailty, one of the common reasons for seeking long-term care. In older adults, nutritional status is known to be associated with oral function; however, it is not yet known if there is a similar association in middle-aged adults. The present study determined the association between nutritional status and oral function in middle-aged adults. MATERIAL AND METHODS: This cross-sectional study was conducted in 117 outpatients aged 40-64 years who underwent dental check-up at a private dental clinic. Factors associated with oral function, including oral moisture, number of teeth present, oral diadochokinesis, tongue pressure, lip-seal strength, and masticatory performance, were evaluated. Body mass index (BMI), fat-free mass index (FFMI), and skeletal muscle mass index (SMI) were analyzed as nutritional statuses. Pearson's correlation analysis was conducted to determine the correlation between nutritional statuses and other variables. Multiple linear regression analysis was performed, with adjustment for age and sex, using BMI, FFMI, or SMI as response variables and oral moisture, maximum tongue pressure, lip-seal strength, oral diadochokinetic rate, and masticatory performance as explanatory variables. RESULTS: All nutritional statuses showed significant correlation with maximum tongue pressure and lip-seal strength. Multiple linear regression analysis revealed that BMI was associated with maximum tongue pressure and lip-seal strength, whereas FFMI and SMI showed significant association with sex, maximum tongue pressure, and lip-seal strength. CONCLUSIONS: In middle-aged outpatients at a regional dental clinic, lip-seal strength and tongue pressure were positively associated with BMI, FFMI, and SMI.

Intra- and Inter-Investigator Reliability of Measurement of Lip-Seal Strength in Adults.

The purpose of this methodological study was to clarify intra- and inter-investigator reliability of lip-seal strength measurement in adults. Lip-seal strength was measured with a digital medical strain gauge using the button-pull method. The coefficient of variation (CV) of intra-investigator reliability of measurement in 24 healthy adult volunteers (16 men, 8 women; mean age, 26±3 years) ranged from 0.088 to 0.103 (mean for 3 investigators, 0.098). The intraclass correlation coefficient (ICC [1,1]) of intra-investigator reliability of this method of lip-seal strength measurement ranged from 0.759 to 0.832 (mean, 0.804). The ICC (2,1) of inter-investigator reliability of the measured values was 0.737. The CV of intra-investigator reliability of lip-seal strength measurement by a single investigator in 54 adult patients (14 men, 40 women; mean age, 49±16 years) was 0.072. The ICC (1,1) of intra-investigator reliability of this measurement method of lip-seal strength was 0.863. A CV of approximately 0.2 or lower is considered to indicate excellent agreement; an ICC of approximately 0.75 or higher is considered indicative of good reliability. These results demonstrate that measurement of lip-seal strength in adults with this device offers sufficient intra- and inter-investigator reliability.

Influence of chewing on expression level of human beta-defensin 2 and secretory immunoglobulin A in the epithelium.

PURPOSE: This study aimed to clarify the influence of chewing on human ß-defensin 2 (hBD-2) and secretory immunoglobulin A (SIgA) expression levels. METHODS: We included 15 healthy males with no missing teeth (mean age, 25.5±2.5years). Subjects were instructed to chew a piece of gum for 30min. Saliva and skin-extraction samples were collected before and after chewing for 15 and 30min. hBD-2 and SIgA concentrations in the samples were determined using enzyme-linked immunosorbent assay (ELISA). hBD-2 and SIgA expression levels before and after chewing were analyzed using the Mann-Whitney U test, following the Friedman test. The significance level was 0.05. RESULTS: The hBD-2 level in skin-extraction samples was significantly different before (99.4±17.3pg/mL) and after chewing for 30min (142±23.0pg/mL). The SIgA level in skin-extraction samples was also significantly different before (2.39±0.25µg/mL) and after chewing for 30min (3.61±0.33µg/mL). No significant difference was noted in either hBD-2 or SIgA secretion rate in saliva between before and after chewing. CONCLUSIONS: Chewing gum for 30min increased hBD-2 and SIgA expression levels in skin. Moreover, chewing gum could influence the secretion pattern of these two biomolecules on skin, but not in saliva.

Evaluation of Factors Associated with Tongue Coating Status in Elderly with Care Needs.

The tongue surface in older people requiring nursing care is often coated with a layer believed to comprise, keratinized products of degeneration, food residue, bacteria, and leukocytes attached to the tongue papillae. Which factors affect the status of this tongue coating remain to be elucidated, however. The purpose of this study was to evaluate factors related to tongue coating status in older people requiring nursing care. The study participants comprised 41 individuals admitted to special nursing homes for the elderly. After undergoing tooth brushing and tongue cleaning by the facility staff, the participants were required to refrain from oral cleaning until evaluation of tongue coating status, which was performed just after lunch. The moisture level of the tongue surface was measured and total number of oral microbes determined. Food type, care level, and sex were determined by a questionnaire given by the attending nurses. Correlations between the tongue coating status and various factors were analyzed using Spearman's rank correlation coefficient. The participants were divided into 2 groups according to the median value of the tongue coating status. Factors related to tongue coating were analyzed using binomial logistic regression analysis (α=0.05). Tongue coating status showed a significant correlation with the total number of oral microbes on the tongue surface (rS=0.449, p=0.003), type of food (rS=0.388, p=0.012), and care level (rS=-0.308, p=0.050). Logistic regression analysis revealed that the food type of the side dish significantly affected tongue coating status. These results showed a correlation between tongue coating status and type of food of the side dish in older people requiring nursing care.

A 2-year longitudinal study of the relationship between masticatory function and progression to frailty or pre-frailty among community-dwelling Japanese aged 65 and older.

BACKGROUND: An association has recently been reported between frailty and reduced masticatory function; however, the causal relationship remains unclear. OBJECTIVE: The aim of this study was to clarify the relationship between masticatory function and frailty progression. METHODS: Among 6699 individuals aged 65 and older (mean age 72.8 ± 5.2 years) who were invited to participate in comprehensive medical check-ups, 418 who underwent examinations at the Tokyo Metropolitan Institute of Gerontology in both 2013 and 2015 and who met inclusion criteria were included in this study. Frailty was determined with the Kihon Checklist developed by the Japanese Ministry of Health, Labour and Welfare. The following three masticatory functions were evaluated: occlusal force, mixing ability and subjective chewing ability. The following confounding factors were investigated: age, sex, grip strength, comfortable walking speed, Mini-Mental State Examination (MMSE) score, Self-Rating Depression Scale (SDS) score, skeletal mass index (SMI), number of medications taken and number of remaining teeth. Statistical analysis was performed with binomial logistic regression analysis. RESULTS: Logistic regression analysis revealed that comfortable walking speed, SDS score, MMSE score and masticatory function were significantly related to progression to frailty or pre-frailty. Of the three masticatory function items evaluated, mixing ability and subjective chewing ability were related to frailty progression. CONCLUSION: Our results confirm that masticatory function was associated with the progression to pre-frailty or frailty among community-dwelling individuals 65 years and older over the 2-year period of this longitudinal study. Of the masticatory function items evaluated, mixing ability and subjective chewing ability were associated with frailty progression.

Time-dependent effects of tongue cleaning with mouthwash or mouth moisturising gel on the number of microbes on the tongue surface of elders with care needs.

OBJECTIVE: The purpose of this study was to investigate time-dependent change in the number of microbes on the tongue surface after tongue cleaning using a mouthwash or mouth moisturising gel for elders fed with a feeding tube and with care needs. MATERIALS AND METHODS: Twelve elders fed through a feeding tube and with care needs participated in this prospective crossover study. There were four kinds of tongue cleaning modes as follows: (i) tongue cleaning with a mouthwash; (ii) tongue cleaning with a mouth moisturising gel; (iii) tongue cleaning with water; (iv) no tongue cleaning as a negative control. The total number of microbes on the tongue surface was measured using a rapid oral bacteria detection device at baseline, immediately after cleaning, and at 1, 3 and 5 hours after cleaning to evaluate the time-dependent change for each tongue cleaning mode. RESULTS: There were no significant differences regarding microbial count on every measurement in negative control and tongue cleaning with water. There were significant decreases immediately after cleaning, and at 1, 3 and 5 hours after cleaning compared to baseline when the tongue was cleaned with a mouthwash. There was a significant decrease between baseline and immediately after cleaning when the tongue was cleaned with a mouth moisturising gel. CONCLUSION: Tongue cleaning with mouth moisturising gel decreased the number of microbes on the tongue surface immediately after cleaning, and tongue cleaning with mouthwash decreased it for 5 hours.

Effects of chewing rate and reactive hyperemia on blood flow in denture-supporting mucosa during simulated chewing.

PURPOSE: We examined how chewing rate and the extent of reactive hyperemia affect the blood flow in denture-supporting mucosa during chewing. METHODS: The left palatal mucosa was loaded under conditions of simulated chewing or simulated clenching for 30s, and the blood flow during loading was recorded. We compared the relative blood flow during loading under conditions that recreated different chewing rates by combining duration of chewing cycle (DCC) and occlusal time (OT): fast chewing group, typical chewing group, slow chewing group and clenching group. The relationship between relative blood flow during simulated chewing and the extent of reactive hyperemia was also analyzed. RESULTS: When comparing the different chewing rate, the relative blood flow was highest in fast chewing rate, followed by typical chewing rate and slow chewing rate. Accordingly, we suggest that fast chewing increases the blood flow more than typical chewing or slow chewing. There was a significant correlation between the amount of blood flow during simulated chewing and the extent of reactive hyperemia. CONCLUSIONS: Within the limitations of this study, we concluded that slow chewing induced less blood flow than typical or fast chewing in denture-supporting mucosa and that people with less reactive hyperemia had less blood flow in denture-supporting mucosa during chewing.

Influence of anterior palatal coverage on perception and retention in complete dentures.

STATEMENT OF PROBLEM: Oral perception is adversely affected by palatal coverage in complete denture wearers. PURPOSE: The purpose of this study was to determine whether an opening in an anterior palatal base enhanced oral perception and the effect of the size of the opening on retention. MATERIAL AND METHODS: Ten healthy dentate individuals (5 men, 5 women; age range: 22-29 years) participated in the perception test. The time required to sense a nylon thread embedded in test food was measured. The test was performed with 3 types of experimental palatal form: no-opening; small-opening, where the opening was located in the anterior region of the palatal base; and large-opening, where the opening was located between the incisive papilla and the third palatal rugae. No palatal coverage was used as a control. Retention force was measured by pulling and loading tests. In the pulling test, pulling force was applied to 2 points on the experimental denture base, and in the loading test, loading force was applied to 6 points. Response times (sec) and retention forces (N) were analyzed using a 1-way ANOVA for repeated measurements followed by the Bonferroni test for multiple comparisons (α=.05). RESULTS: A significant difference was observed in response time in fiber perception between bases with or without a small opening (P =.017). In the pulling test, retention force with the small-opening type was 4% lower at the molar region, and 35% lower at the center of gravity than in the no-opening type. Retention force in the large-opening type was lower than in the small-opening type. In the loading test, retention force was 13 N or higher in all 3 types. CONCLUSIONS: The small-opening type of palatal coverage improved oral perception and demonstrated sufficient retention force.

Color differences between artificial and natural teeth in removable partial denture wearers.

The purpose of this study was to investigate differences between natural tooth color and that selected for artificial teeth in partial dentures at our department with a view to establishing criteria for obtaining greater harmonization between colors. The participants in this study comprised partial denture wearers visiting the Department of Prosthodontics, Tokyo Dental College Chiba Hospital, in whom both artificial teeth and natural teeth were present in the maxillary anterior tooth area. Natural tooth color was measured according to VITA classical shade guide number using a dental color measurement apparatus. Artificial tooth color in partial dentures produced at our department was investigated by referring to medical records. Color of 28 participants' natural teeth and 345 participants' artificial teeth was investigated. Differences in color distribution between the natural and artificial tooth were analyzed using the Fisher exact test. The most frequent color of natural tooth was C-type, accounting for 39%, followed by D- at 32%, A-at 22% and B-type at 7%. In terms of artificial tooth color, A-type was the most common (97%). The color distribution of natural teeth differed significantly from that of artificial teeth in partial dentures. These results suggest that artificial tooth color did not harmonize with the color of the natural teeth in partial denture wearers.