Low tongue pressure and depression using Kihon Checklist for assessing frailty status among community-dwelling Japanese older adults: A pilot study.

BACKGROUND: Evaluation of low tongue pressure is used to diagnose oral hypofunction. The pathophysiology of oral hypofunction is hypothesized to be associated with oral dysfunction related to ageing. Depression in older adults is a major problem and is related to handgrip strength, which is related to tongue pressure. We hypothesized that low tongue pressure could indicate depression mood in community-dwelling older adults. OBJECTIVES: This study aimed to measure maximum tongue pressure and compare it to the responses to the Kihon Checklist (KCL), which is used to check mental and physical deterioration of community-dwelling older adults. METHODS: A total of 49 community-dwelling independent older adults with stable dental condition (23 men, 26 women; median age, 79 years) answered the KCL, which contained questions on frailty status, cognitive function, nutritional and sarcopenia status. Oral function was measured to assess oral hypofunction. The relationship between tongue pressure differences and frailty status, cognitive function, nutritional and sarcopenia status was analysed using logistic regression analyses after adjusting for age and sex. RESULTS: Nine participants (6 men and 3 women; median age, 81 years) had a tongue pressure <23.0 kPa, which was the lowest limit of the standard value of maximum tongue pressure in patients aged ≥70 years. Logistic regression analyses showed that only Question 21, which is related to a lack of fulfilment in daily life, was significantly associated with low tongue pressure (p = .027). CONCLUSION: Low tongue pressure may be associated with sociopsychological factors in older adults.

Associations of sex, age, and number of remaining teeth with performance on oral hypofunction tests.

INTRODUCTION: Oral hypofunction comprises seven aspects of oral condition, including oral hygiene, oral dryness, bite strength, tongue-lip motor function, tongue pressure, masticatory function, and swallowing function. Each of these seven has a single diagnostic criterion; however, the use of a single indicator without consideration of sex, age, or other factors is controversial. The purpose of this study was to evaluate the association between the oral hypofunction test and sex, age, and number of remaining teeth. METHODS: The study was conducted at 12 facilities by the members of the Japanese Society of Geriatric Dentistry during April to December 2019. The participants comprised 181 healthy older adults aged 65 years and over (56.9% female; age range 65-95 years) who regularly visited these facilities. All tests of oral function and oral status available in Japan were performed on the participants, and the association between these tests and sex, age, and number of remaining teeth was examined. RESULTS: Sex differences were observed in masticatory function, bite force, lip closure force, jaw-opening force, oral diadochokinesis "ka," and tongue coating index (p < .05). In men, age was weakly (r = 0.20-0.40) associated with masticatory function, jaw-opening force, maximum tongue pressure, oral diadochokinesis, and swallowing function. In women, the number of remaining teeth, masticatory function, jaw-opening force, and oral diadochokinesis "ta" and "ka" was also weakly associated with age. CONCLUSIONS: Performance on the oral hypofunction test differs by sex, age, and number of remaining teeth. This means that the current single criterion for evaluation requires caution in its interpretation.

Disinfectant Susceptibility of Third-Generation-Cephalosporin/Carbapenem-Resistant Gram-Negative Bacteria Isolated from the Oral Cavity of Residents of Long-Term-Care Facilities.

We have recently reported the isolation of third-generation-cephalosporin-resistant Gram-negative bacteria from the oral cavity of residents of a long-term-care facility (LTCF). Since disinfectants are often used in the oral cavity, it is important to investigate the disinfectant susceptibility of oral bacteria. Here, we evaluated the susceptibilities of Gram-negative antimicrobial-resistant bacteria (GN-ARB), including Pseudomonas, Acinetobacter, and Enterobacteriaceae, obtained from the oral cavity of residents of LTCFs to povidone-iodine (PVPI), cetylpyridinium chloride (CPC), benzalkonium chloride (BZK), and chlorhexidine chloride (CHX). We also evaluated the susceptibilities of isolates from the rectum to the same agents to compare the susceptibility profiles of oral and rectal isolates. Next, we investigated the relationship between their susceptibility and disinfectant resistance genes delineated by whole-genome sequencing of the isolates. Additionally, we evaluated the correlation between disinfectant-resistant GN-ARB and clinical information. In oral GN-ARB, the MIC of PVPI showed almost identical values across isolates, while the MICs of CPC, BZK, and CHX showed a wide range of variation among species/strains. In particular, Pseudomonas aeruginosa exhibited high-level resistance to CPC and BZK. The disinfectant susceptibility of rectal GN-ARB showed a tendency similar to that of oral GN-ARB. The presence of qacEΔ1 was correlated with CPC/BZK resistance in P. aeruginosa, while other species exhibited no correlation between qacEΔ1 and resistance. Multiple analyses showed the correlation between the presence of CPC-resistant bacteria in the oral cavity and tube feeding. In conclusion, we found that some oral GN-ARB isolates showed resistance to not only antibiotics but also disinfectants. IMPORTANCE Antibiotic-resistant bacteria (ARB) are becoming a serious concern worldwide. We previously reported the isolation of third-generation-cephalosporin-resistant Gram-negative bacteria from the oral cavity of residents of a long-term-care facility (LTCF). To prevent infection with ARB in hospitals and eldercare facilities, we must pay more attention to the use of not only antibiotics but also disinfectants. However, the effect of disinfectants on ARB is unclear. In this study, we evaluated the susceptibility of Gram-negative ARB (GN-ARB) from the oral cavity of residents of LTCFs to some disinfectants that are often used for the oral cavity; we found that some isolates showed resistance to several disinfectants. This is the first comprehensive analysis of the disinfectant susceptibility of oral GN-ARB. These results provide some important information for infection control and suggest that disinfectants should be applied carefully.

Experimental tooth loss affects spatial learning function and blood-brain barrier of mice.

OBJECTIVE: This study aims to investigate how experimental tooth loss affected learning, memory function, and brain pathophysiology in mice. MATERIALS AND METHODS: The mice (C57BL/6 J, 2-month-old, male) were divided into tooth loss and control groups. The behavioral test battery was performed at 6 and 12 months after tooth extraction. The protein levels of the tight junctions in the brains of the mice were analyzed. Hippocampal astrocyte was measured using immunohistochemical staining. RESULTS: The results of behavioral tests and biochemical analysis performed during the 6 months observation period did not show significant differences between the groups. However, the escape latency in the tooth loss group was significantly longer than that in the control group at the 12 months after tooth extraction. The level of claudin-5 decreased in the tooth loss group. Additionally, hippocampal astrogliosis was found in the tooth loss group. CONCLUSIONS: Experimental tooth loss reduced the level of claudin-5 and caused astrogliosis in the brains of mice, which was accompanied by deterioration of learning functions. This study may provide a new insight about the association between tooth loss and cognitive dysfunction.

Age-related changes in oral tactile and thermal sensation throughout adulthood.

Although the life expectancy of women is over 80 years in many countries, oral sensation has scarcely been compared between adults ≥ 80 years and younger age groups. The purpose of this study was to clarify age-related changes in oral sensation throughout adulthood. After exclusion of individuals with factors that might have confounded somatosensory performance, 123 female participants were divided into four age groups: 20-39 years, 40-59 years, 60-79 years, and 80-96 years. Perceptions of tactile and thermal sensations were examined at points on the anterior and posterior palate, anterior and posterior tongue, lower labial-attached gingiva, lower lip, and buccal mucosa; two-point discrimination was examined only on the tongue. The tactile and two-point discrimination thresholds for the anterior and posterior tongue were significantly higher in the 80-96-year-old group than in any other age group (p < 0.05). The tactile threshold for the buccal mucosa was significantly higher in the 80-96-year-old group than in the 60-79-year-old group (p < 0.05). The percentage of participants able to perceive a warm stimulus (50 °C) in the buccal mucosa was significantly lower in the 80-96-year-old group than in the 20-39-year-old group (p < 0.05). Only the topography of the warm sensation perception changed with age. This cross-sectional study suggests that oral tactile and thermal sensation for warm stimuli deteriorates with age in a site-specific manner, especially after the age of 80 years, but the same does not occur with cool stimuli.

Antimicrobial effects of viscous mouthrinses containing cetylpyridinium chloride and isopropyl methylphenol.

PURPOSE: To evaluate the in vitro antimicrobial effect of low- and high-viscosity experimental mouthrinses containing cetylpyridinium chloride (CPC) and 4-isopropyl-3-methylphenol (IPMP) on Streptococcus pneumoniae, Klebsiella pneumoniae, Porphyromonas gingivalis, Streptococcus mutans, and Candida albicans. METHODS: Low- and high-viscosity experimental mouthrinses containing 0.05% CPC and 0.1% IPMP were fabricated. Non-viscous mouthrinses containing either CPC- or IPMP were used as controls. The antimicrobial activity (sterilization or exposure time) of mouthrinses was evaluated based on the bactericidal criterion of <10¹ viable cells in 0.1 mL of culture medium. RESULTS: The sterilization time of the low-viscosity experimental mouthrinse was shorter than that of the high-viscosity mouthrinse. However, whereas a 10-minute exposure to the low-viscosity mouthrinse resulted in no viable cells of C. albicans, neither the CPC- or IPMP mouthrinses had an antimicrobial effect for the same exposure time. These findings show that the low-viscosity experimental mouthrinse containing anodal CPC and neutral IPMP exhibited superior antimicrobial effects against pneumonia- and oral infection-related bacteria compared with the control mouthrinses. CLINICAL SIGNIFICANCE: In Japan, the oral care with the low-viscosity experimental mouthrinse containing CPC and IPMP as alternatives to those based on chlorhexidine are available for preventing the development of pneumonia- and oral infection-related bacteria.

Reliability and comparability of methods for assessing oral function: Chewing, tongue pressure and lip force.

BACKGROUND: Quantitative clinical assessment tests for oral function have become popular in patient assessment; however, their comparability remains unclear. OBJECTIVE: To assess the reliability and comparability of pairs of different instruments for measuring maximum tongue pressure (MTP), chewing function (CF) and maximum lip force (MLF), and to analyse the influence of subjects' characteristics on the applied instruments. METHODS: Each pair of instruments, as well as a single device measuring the maximum voluntary bite force (MBF), was assessed across 26 healthy volunteers. The respective pairs of devices were compared using Bland-Altman plots and linear regression analysis. Furthermore, the influence of age, occlusal support zones, number of functional occlusal units, MBF, MTP and MLF were investigated as predictors on CF using a generalised estimating equation model. RESULTS: Neither the two assessments of CF, nor of MLF were correlated to each other, but there was a significant correlation between the assessments of MTP. Hue-Check Gum was able to demonstrate a significantly higher CF in younger compared to older individuals (P = .004) and individuals with high numbers compared to low numbers of occlusal units (P < .001). Those differences could not be demonstrated with the Vivident chewing gum. CONCLUSION: The absolute values of MTP assessed by the two applied devices cannot directly be compared, although normalised values may be directly comparable. Moreover, our observations suggest that the Hue-Check Gum was able to discriminate the effects of age and the number of occlusal units on CF. Our observations suggest that the two gums cannot be used interchangeably.

Association between buccal mucosa ridging and oral or occlusal status among older people.

OBJECTIVES: This study aimed to evaluate the association between buccal mucosa ridging and oral or occlusal statuses among older people. SUBJECTS AND METHODS: This cross-sectional study examined 262 independent older people (mean age, 74.2 ± 5.9 years) who participated in the Kyoto Elderly Physical Fitness Measurement Research Project. The predictor variables were oral statuses (number of present teeth and torus palatinus, torus mandibularis, temporomandibular joint noise, clenching, or grinding) and oral functions (occlusal pressure, cheek pressure, oral diadochokinesis, and tongue pressure). The outcome variable was the buccal mucosa ridging status (presence or absence). Additional variables were age, sex, body mass index, grip strength, and wearing dentures. We compared these variables between participants with and without buccal mucosa ridging using a univariate analysis and multiple logistic regression analysis. RESULTS: Buccal mucosa ridging was present in 177 (67.6%) people. Multiple logistic regression analysis revealed a close association of buccal mucosa ridging with torus mandibularis, tooth clenching and grinding and occlusal pressure, and cheek pressure. CONCLUSIONS: Over 50% of the participants showed buccal mucosa ridging; this was significantly associated with higher cheek pressure, lower occlusal pressure, torus mandibularis, and tooth clenching and grinding.

Effect of polymerization temperature on the properties of autopolymerizing resin.

STATEMENT OF PROBLEM: The polymerization conditions of an autopolymerizing resin affect its physical properties, and at chairside, 3 different methods are commonly used: cooling in cold water, warming in warm water, and heating in hot water. However, the effects of polymerization temperature on the physicomechanical properties of autopolymerizing resin are unclear. PURPOSE: The purpose of this in vitro study was to determine the effect of polymerization temperature on the physicomechanical properties of autopolymerizing resin, including shrinkage, water absorption, surface roughness, amount of residual monomer, and flexural strength. MATERIAL AND METHODS: The experiment was designed to simulate a direct technique commonly used for the fabrication of interim crowns. Autopolymerizing resin specimens were made according to the powder-to-liquid ratio recommended by the manufacturer and soaked in water at 13°C, 37°C, or 60°C for 2 minutes to mold the resin until polymerization was completed 4 minutes after mixing. Shrinkage, water absorption rate, surface roughness, residual monomer, and flexural strength were measured immediately after polymerization and after 1, 3, and 7 days in distilled water at 37°C. Differences among these properties among the 3 different temperatures groups were statistically analyzed by using 1-way ANOVA and the Tukey honest significant difference test (α=.05). RESULTS: Shrinkage tests showed that the 13°C group had significantly lower shrinkage (P=.004 for 37°C and P<.001 for 60°C) than the other groups immediately after specimen preparation. The 13°C group had significantly higher surface roughness after 0 (P<.001 for 37°C and P<.001 for 60°C), 1 (P=.025 for 37°C and P=.012 for 60°C), 3 (P<.001 for 37°C and P<.001 for 60°C), and 7 days (P<.001 for 37°C and P<.001 for 60°C) than those in the other groups and significantly higher water absorption rates (P=.033 for 37°C and P<.001 for 60°C) than the other groups during the 7 days after fabrication. However, the 13°C group showed significantly higher weight percentage of residual monomers than the 60°C group at 0 (P<.001) and 1 day (P<.001). Finally, 3-point bend tests showed that the 13°C group had significantly lower flexural strength at 0 (P<.001), 1 (P<.001), 3 (P<.001), and 7 days (P<.001) than the other groups. CONCLUSIONS: The temperature environment during dental chairside polymerization of the autopolymerizing resin affected the physicomechanical properties of shrinkage, water absorption rate, surface roughness, residual monomer, and flexural strength.

Oral hypofunction in the older population: Position paper of the Japanese Society of Gerodontology in 2016.

BACKGROUND: There is growing international interest in identifying the effects of ageing on oral health and on appropriate strategies for managing oral disorders. The Japanese Society of Gerodontology (JSG), as the official representative of researchers and clinicians interested in geriatric dentistry in Japan, makes several recommendations on the concept of "oral hypofunction." AIMS: This study proposes diagnostic criteria and management strategies to reduce the risk of oral hypofunction among older people. CONCEPTUAL FRAMEWORK: We define oral hypofunction as a presentation of 7 oral signs or symptoms: oral uncleanness; oral dryness; decline in occlusal force; decline in motor function of tongue and lips; decline in tongue pressure; decline in chewing function; and decline in swallowing function. The criteria of each symptom were determined based on the data of previous studies, and oral hypofunction was diagnosed if the criteria for 3 or more signs or symptoms were met. CONCLUSIONS: We recommend that more evidence should be gathered from clinical studies and trials to clarify our diagnostic criteria and management strategies.

Prevalence of Torus Mandibularis in Young Healthy Dentate Adults.

PURPOSE: There have been only a few reports on the prevalence of torus mandibularis (TM) in young adult patients, and TM can have various adverse effects on oral and occlusal states in middle-age patients. This study was designed to determine the association between TM status and oral and occlusal states in young healthy dentate adults. MATERIALS AND METHODS: This was a cross-sectional study; the sample population included students at Hiroshima University (Hiroshima, Japan) who participated for practical education. The predictor variables in this study included oral symptoms (temporomandibular joint noise, tooth clenching and grinding, buccal mucosa ridging, dental attrition, and tongue habit), oral anatomy (occlusal vertical dimension), and oral function (average occlusal pressure, occlusal contact area, and maximum voluntary tongue pressure). The outcome variable was TM status (present or absent). Additional variables were demographic in nature and included age, number of residual teeth, body weight, and gender. These variables were compared among participants with and without TM using univariate analysis and multiple logistic regression analysis. Statistical analyses were carried out using SPSS Statistics 19 for Windows (IBM Corp, Armonk, NY); a P value less than .05 was considered significant. RESULTS: Of 204 participants included in the study, 50% were men and 50% were women. The mean age was 22.4 ± 2.7 years. TM was present in 119 (58.3%). Multiple logistic regression analysis showed that TM status was associated with dental attrition and occlusal contact area (P < .05). CONCLUSIONS: This study showed that TM was present in more than half the young healthy dentate participants and was closely associated with dental attrition and occlusal contact area. This study will provide readers with useful information to help prevent the development of TM before middle age.

Molar loss and powder diet leads to memory deficit and modifies the mRNA expression of brain-derived neurotrophic factor in the hippocampus of adult mice.

BACKGROUND: It is known that tooth loss is known to be a risk factor for Alzheimer's disease and soft diet feeding induces memory impairment. Recent studies have shown that brain-derived neurotrophic factor (BDNF) is associated with tooth loss or soft diet in young animal model, and that BDNF expression is decreased in patients with Alzheimer's disease. However, single or combined effect of tooth loss and/or soft diet on brain function has not fully understood. Here we examined the effect of molar loss and powder diet on memory ability and the expression of BDNF mRNA in the hippocampus of adult C57BL/6J mice. Twenty eight-weeks-old C57BL/6J mice were divided into intact molar group and extracted molar group. They were randomly divided into the I/S group (Intact upper molar teeth/Solid diet feeding), the E/S group (Extracted upper molar teeth/Solid diet feeding), the I/P group (Intact upper molar teeth/Powder diet feeding), and the E/P group (Extracted upper molar teeth/Powder diet feeding). The observation periods were 4 and 16-week. To analyze the memory ability, the step-through passive avoidance test was conducted. BDNF-related mRNA in the hippocampus was analyzed by real-time polymerase chain reaction (RT-PCR). RESULTS: At 4 weeks later, we performed memory test and isolated brains to analyze. There were no differences in memory function and BDNF mRNA level between these four groups. However, at 16 weeks later, E/S and E/P group showed memory impairment, and decreased level of BDNF mRNA. Whereas, the powder diet had no effect on memory function and BDNF mRNA level even at 16 weeks later. CONCLUSIONS: These results suggest that the effect of molar loss and powder diet on memory function and BDNF mRNA levels were different, molar loss may have a greater long-term effect on memory ability than powder diet does.

Utility of intraoral scanner imaging for dental plaque detection.

Purpose: Oral hygiene, maintained through plaque control, helps prevent periodontal disease and dental caries. This study was conducted to examine the accuracy of plaque detection with an intraoral scanner (IOS) compared to images captured with an optical camera. Materials and Methods: To examine the effect of color tone, artificial tooth resin samples were stained red, blue, and green, after which images were acquired with a digital single-lens reflex (DSLR) camera and an IOS device. Stained surface ratios were then determined and compared. Additionally, the deviation rate of the IOS relative to the DSLR camera was computed for each color. In the clinical study, following plaque staining with red disclosing solution, the staining was captured by the DSLR and IOS devices, and the stained area on each image was measured. Results: The stained surface ratios did not differ significantly between DSLR and IOS images for any color group. Additionally, the deviation rate did not vary significantly across colors. In the clinical test, the stained plaque appeared slightly lighter in color, and the delineation of the stained areas less distinct, on the IOS compared to the DSLR images. However, the stained surface ratio was significantly higher in the IOS than in the DSLR group. Conclusion: When employing IOS with dental plaque staining, the impact of color was minimal, suggesting that the traditional red stain remains suitable for plaque detection. IOS images appeared relatively blurred and enlarged relative to the true state of the teeth, due to inferior sharpness compared to camera images.

Comparison of plaque control record measurements obtained using intraoral scanner and direct visualization.

OBJECTIVE: Intraoral scanner (IOS) can acquire three-dimensional color images of teeth. Thus, the detection of areas with plaque adhesion stained by plaque-disclosing solutions using an IOS could be a potential oral hygiene evaluation method. This study aimed to verify the usefulness of obtaining O'Leary's plaque control record (PCR) measurements using an IOS in clinical practice. METHODS: Twenty patients with >20% PCR measurements who underwent oral prophylaxis were enrolled in this study. A plaque-disclosing gel was applied to stain the areas with plaque adhesion, and the dentition was scanned using the IOS. The PCR values obtained via the direct method and those obtained using the digital image were compared for the entire dentition, maxillary total area, the labial and palatal aspects of the maxillary anterior teeth, the buccal and palatal aspects of the maxillary posterior teeth, mandibular total area, the labial and lingual aspects of the mandibular anterior teeth, and the buccal and lingual aspects of the mandibular posterior teeth. RESULTS: The IOS group tended to have higher values than the direct observation group. The labial and palatal aspect of the maxillary anterior teeth, the labial and lingual aspects of the mandibular anterior teeth did not differ significantly between the groups. CONCLUSION: Plaque adhesion was visualized easily and conclusively using an IOS. As the large tip size often hinders its use, it is necessary to develop a smaller IOS tip in the future.

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. Waveforms longer than 0.25 s with the two amplitude conditions, exceeding twice the baseline and >5% of maximum voluntary clenching, were extracted. In addition, the number of bursts and episodes (groups of bursts), burst duration, and burst peak amplitude were calculated for each participant. RESULTS: There were no significant differences in the EMG parameters between the groups with and without awareness of d-TC. Additionally, the frequency distribution of the number of EMG waveforms exhibited wide ranges and substantial overlap between the two groups. CONCLUSIONS: The variability in the number of bursts and episodes, burst peak amplitude, and burst duration among subjects suggests the need for an objective classification of d-AB severity based on EMG values. The absence of significant differences and large overlap in frequency distributions between the groups with and without awareness of d-TC indicate difficulty in predicting muscle activity solely based on awareness of d-AB.

Relationship of oral bacterial number with medical hospitalization costs in analysis of Diagnosis Procedure Combination database from single institution in Japan.

Oral bacteria are known to be associated with perioperative complications during hospitalization. However, no presented reports have clarified the relationship of oral bacterial number with medical costs for inpatients. The Diagnosis Procedure Combination (DPC) database system used in Japan provides clinical information regarding acute hospital patients. The present study was conducted to determine the association of oral bacterial numbers in individual patients treated at a single institution with length of hospital stay and medical costs using DPC data. A total of 2369 patients referred by the medical department to the dental department at Hiroshima University Hospital were divided into the low (n = 2060) and high (n = 309) oral bacterial number groups. Length of hospital stay and medical costs were compared between the groups, as well as the associations of number of oral bacteria with Charlson comorbidity index (CCI)-related diseases in regard to mortality and disease severity. There was no significant difference in hospital stay length between the low (24.3 ± 24.2 days) and high (22.8 ± 20.1 days) oral bacterial number groups. On the other hand, the daily hospital medical cost in the high group was significantly greater (US$1456.2 ± 1505.7 vs. US$1185.7 ± 1128.6, P < 0.001). Additionally, there was no significant difference in CCI score between the groups, whereas the daily hospital medical costs for patients in the high group treated for cardiovascular disease or malignant tumors were greater than in the low number group (P < 0.05). Multivariate regression analysis was also performed, which showed that oral bacterial number, age, gender, BMI, cardiovascular disease, diabetes, malignant tumor, and hospital stay length were independently associated with daily hospitalization costs. Monitoring and oral care treatment to lower the number of oral bacteria in patients affected by cardiovascular disease or cancer may contribute to reduce hospitalization costs.

Antimicrobial adhesive polyurethane gel sheet with cetylpyridinium chloride-montmorillonite for facial and somato prosthesis fastening.

Purpose Existing options for attaching facial and somato prostheses, such as skin adhesives, are problematic because of microbial colonization and skin irritation. This study aims to evaluate the suitability of adhesive polyurethane gel sheets containing cetylpyridinium chloride (CPC)-montmorillonite (Mont) for prosthesis fastening.Methods Adhesive gel sheets were fabricated as mixtures of base resin (99.6 wt% polyol) and hardening agent at a ratio of 3:1 with 0 (control), 2, 5, 10, or 15 wt% CPC-Mont. The controlled release of CPC, antimicrobial activity, in vitro skin irritation, and adhesive force against silicone and human skin at different blending ratios were determined. Statistical analyses of the data were performed using one-way analysis of variance (ANOVA), analysis of covariance (ANCOVA), Tukey's test, or single regression analysis, as appropriate.Results The amount of CPC released increased with the CPC-Mont blending ratio and was linearly proportional to the surface occupation area ratio of CPC-Mont. The samples with >5 wt% CPC-Mont exhibited antimicrobial activity against Staphylococcus aureus at an exposure time of 0 d, and samples with >2 wt% CPC-Mont exhibited antimicrobial activity against Candida albicans at an exposure time of 1 d. All samples were classified as non-irritant based on an in vitro skin irritation test. The adhesive force on the silicone material and human skin decreased with increasing CPC-Mont blending ratio.Conclusions Samples with 5 wt% CPC-Mont are potential candidates as antimicrobial adhesive polyurethane gel sheets for fastening facial and somato prostheses.

Radiopaque properties of polyetheretherketone crown at laboratory study.

OBJECTIVES: There have been no reports on the radiopaque properties of new polyetheretherketone (PEEK) crowns for locating crowns during accidental ingestion or aspiration and detection of secondary caries, which is essential information for clinical application. This study aimed to investigate whether the radiopaque properties of PEEK crowns could be used to identify the site of accidental ingestion or aspiration and detect secondary caries. METHODS: Four types of crowns were fabricated: three non-metal crowns (PEEK, hybrid resin, and zirconia) and one full metal cast crown (gold-silver-palladium alloy). Initially, the images for these crowns were compared using intraoral radiography, chest radiography, cone-beam computed tomography (CBCT), and multi-detector computed tomography (MDCT); computed tomography (CT) values were calculated. Subsequently, the images for the crowns placed on the secondary caries model with two artificial cavities were compared using intraoral radiography. RESULTS: The PEEK crowns displayed the lowest radiopaque properties on radiography and very few artifacts were observed on CBCT and MDCT. On the other hand, the CT values of the PEEK crowns were a little lower than those of the hybrid resin crowns and considerably lower than the zirconia and full metal cast crowns. The cavity could be detected in the PEEK crown-placed secondary caries model through intraoral radiography. CONCLUSIONS: This simulated study of radiopaque properties with four types of crowns suggested that a radiographic imaging system can be used to identify the site of accidental ingestion and aspiration of PEEK crowns and to detect secondary caries of the abutment tooth within a PEEK crown.

Mouse maternal odontogenic infection with Porphyromonas gingivalis induces cognitive decline in offspring.

Introduction: Porphyromonas gingivalis (P. gingivalis), a major periodontal pathogen, causes intrauterine infection/inflammation. Offspring exposed to intrauterine infection/inflammation have an increased risk of neurological disorders, regardless of gestational age. However, the relationship between maternal periodontitis and offspring functional/histological changes in the brain has not yet been elucidated. Methods: In this study, we used a gestational mouse model to investigate the effects of maternal odontogenic infection of P. gingivalis on offspring behavior and brain tissue. Results: The step-through passive avoidance test showed that the latency of the acquisition trial was significantly shorter in the P. gingivalis group (p < 0.05), but no difference in spontaneous motor/exploratory parameters by open-field test. P. gingivalis was diffusely distributed throughout the brain, especially in the hippocampus. In the hippocampus and amygdala, the numbers of neuron cells and cyclic adenosine monophosphate response element binding protein-positive cells were significantly reduced (p < 0.05), whereas the number of ionized calcium binding adapter protein 1-positive microglia was significantly increased (p < 0.05). In the hippocampus, the number of glial fibrillary acidic protein-positive astrocytes was also significantly increased (p < 0.05). Discussion: The offspring of P. gingivalis-infected mothers have reduced cognitive function. Neurodegeneration/neuroinflammation in the hippocampus and amygdala may be caused by P. gingivalis infection, which is maternally transmitted. The importance of eliminating maternal P. gingivalis-odontogenic infection before or during gestation in maintenance healthy brain function in offspring should be addressed in near future.

Developmental impairments of craniofacial bone and cartilage in transgenic mice expressing FGF10.

Mutations in a common extracellular domain of fibroblast growth factor receptor (FGFR)-2 isoforms (type IIIb and IIIc) cause craniosynostosis syndrome and chondrodysplasia syndrome. FGF10, a major ligand for FGFR2-IIIb and FGFR1-IIIb, is a key participant in the epithelial-mesenchymal interactions required for morphogenetic events. FGF10 also regulates preadipocyte differentiation and early chondrogenesis in vitro, suggesting that FGF10-FGFR signaling may be involved in craniofacial skeletogenesis in vivo. To test this hypothesis, we used a tet-on doxycycline-inducible transgenic mouse model (FGF10 Tg) to overexpress Fgf10 from embryonic day 12.5. Fgf10 expression was 73.3-fold higher in FGF10 Tg than in wild-type mice. FGF10 Tg mice exhibited craniofacial anomalies, such as a short rostrum and mandible, an underdeveloped (cleft) palate, and no tympanic ring. Opposite effects on chondrogenesis in different anatomical regions were seen, e.g., hyperplasia in the nasal septum and hypoplasia in the mandibular condyle. We found an alternative splicing variant of Fgfr2-IIIb with a predicted translation product lacking the transmembrane domain, and suggesting a soluble form of FGFR2-IIIb (sFGFR2-IIIb), differentially expressed in some of the craniofacial bones and cartilages. Thus, excessive FGF10 may perturb signal transduction of the FGF-FGFR, leading to craniofacial skeletal abnormalities in FGF10 Tg mice.