Oral and rectal colonization of methicillin-resistant Staphylococcus aureus in long-term care facility residents and their association with clinical status

Staphylococcus aureus is a commensal bacterium in humans, but it sometimes causes opportunistic infectious diseases such as suppurative skin disease, pneumonia, and enteritis. Therefore, it is important to determine the prevalence of S. aureus and methicillin-resistant S. aureus (MRSA) in individuals, especially older adults. In this study, we investigated the prevalence of S. aureus and MRSA in the oral cavity and feces of residents in long-term care facilities (LTCFs). S. aureus was isolated from the oral cavity of 61/178 (34.3%) participants, including 28 MRSA-positive participants (15.7%), and from the feces of 35/127 (27.6%) participants, including 16 MRSA-positive participants (12.6%). S. aureus and MRSA were isolated from both sites in 19/127 individuals (15.0%) and 10/127 individuals (7.9%), respectively. Among 19 participants with S. aureus isolation from both sites, 17 participants showed the same sequence type (ST) type. Then, we analyzed the correlation of S. aureus and MRSA in the oral cavity and rectum with the participant's condition. S. aureus and MRSA positivity in the oral cavity was significantly related to tube feeding, while there was no correlation of rectal S. aureus/MRSA with any factors. Our findings regarding the oral inhabitation of MRSA and its risk factors indicate the importance of considering countermeasures against MRSA infection in LTCFs.

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.

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.

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.

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.

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.

Oral and Rectal Colonization by Antimicrobial-Resistant Gram-Negative Bacteria and Their Association with Death among Residents of Long-Term Care Facilities: A Prospective, Multicenter, Observational, Cohort Study

INTRODUCTION

The prevalence of antimicrobial-resistant bacteria (ARB) in long-term care facilities (LTCFs) remains unclear. Furthermore, the effect of ARB colonization on the clinical outcomes of LTCF residents has not been explored.

METHODS

We conducted a prospective multicenter cohort study and investigated the residents (N = 178) of six Japanese LTCFs (three Welfare Facilities for the Elderly Requiring Long-term Care and three Geriatric Health Service Facilities) for oral and rectal carriage of ARB. The clinical outcomes of the residents were evaluated based on isolating bacterial strains and subjecting them to whole-genome sequencing.

RESULTS

Of the 178 participants, 32 belonging to Geriatric Health Service Facilities with no information on their clinical outcome were excluded, and the remaining 146 were followed up for at most 21 months. Extended-spectrum β-lactamases (ESBL)-producing Enterobacterales and Pseudomonas aeruginosa were detected in 42.7% (n = 76) and 2.8% (n = 5) of the rectal swabs and 5.6% (n = 10) and 3.4% (n = 6) of the oral swabs, respectively. Detection of ARB in the oral and rectal cavities showed remarkable association with enteral nutrition. Further, P. aeruginosa was significantly associated with an increase in mortality of the residents, but there were not significant association between ESBL-producing Enterobacterales and mortality. Core-genome phylogeny of P. aeruginosa revealed a wide-spread distribution of the isolated strains across the phylogeny, which included a cluster of ST235 strains with substantially higher biofilm formation ability than the other isolated P. aeruginosa strains.

DISCUSSION/CONCLUSION

This study is the first to investigate the carriage of both oral and rectal ARB, genomic relatedness and determinants of antimicrobial resistance in isolated strains, and clinical outcomes of LTCF residents. Our study provides the first direct evidence for the burden of antimicrobial resistance in LTCFs.

Investigation to Predict Primary Implant Stability Using Frictional Resistance Torque of Tap Drilling

Objectives

The purpose of this experimental study was to investigate the correlation between the frictional resistance torque of tap drilling prior to implant placement and the primary stability after implant placement.

Material and Methods

Solid rigid polyurethane bone blocks of four different densities were used in this study. A computerized surgical implant motor device was utilized to measure the frictional resistance torque of tap drilling. After the tap torque was measured, the dental implants were inserted at the prepared sites. During the implantation, the insertion torque was recorded, and resonance frequency analysis was performed, the value of which was calculated as the implant stability quotient. Thereafter, the correlation between the tap torque and the primary stability of the implant was evaluated and compared with the standard drilling protocol.

Results

A significant positive correlation was found between the tap torque and insertion torque (Pearson's r = 0.88, P < 0.0001). Similarly, there was a positive correlation between the tap torque and implant stability quotient (Pearson's r = 0.69, P < 0.0001).

Conclusions

These results suggest that measurement of the frictional resistance torque of tap drilling prior to implant placement could provide helpful information for implant primary stability.

Prenatal exposure to valproic acid causes allodynia associated with spinal microglial activation

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and social interaction and the presence of restricted, repetitive behaviors. Additionally, difficulties in sensory processing commonly occur in ASD. Sensory abnormalities include heightened or reduced sensitivity to pain, but the mechanism underlying sensory phenotypes in ASD remain unknown. Emerging evidence suggests that microglia play an important role in forming and refining neuronal circuitry, and thus contribute to neuronal plasticity and nociceptive signaling. In the present study, we investigated the age-dependent tactile sensitivity in an animal model of ASD induced by prenatal exposure to valproic acid (VPA) and subsequently assessed the involvement of microglia in the spinal cord in pain processing. Pregnant ICR (CD1) mice were intraperitoneally injected with either saline or VPA (500 mg/kg) on embryonic day 12.5. Male offspring of VPA-treated mothers showed mechanical allodynia at both 4 and 8 weeks of age. In the spinal cord dorsal horn in prenatally VPA-treated mice, the numbers and staining intensities of ionized calcium-binding adapter molecule 1-positive cells were increased and the cell bodies became enlarged, indicating microglial activation. Treatment with PLX3397, a colony-stimulating factor 1 receptor inhibitor, for 10 days resulted in a decreased number of spinal microglia and attenuated mechanical allodynia in adult mice prenatally exposed to VPA. Additionally, intrathecal injection of Mac-1-saporin, a saporin-conjugated anti-CD11b antibody to deplete microglia, abolished mechanical allodynia. These findings suggest that prenatal VPA treatment causes allodynia and that spinal microglia contribute to the increased nociceptive responses.

Association between dietary hardness score and activities of daily living among individuals aged 90 years

Objectives

With the rapidly aging world population, Japan has many older people with difficulties in maintaining oral health. This study aimed to investigate the relationship between dietary hardness score and performance of activities of daily living (ADL) of 90‐year‐old individuals in rural areas of Japan.

Material and Methods

A total of 236 individuals (64 men and 172 women) aged 90 years in Mitsugi town, Hiroshima, Japan, were included. Assessment of oral status and survey of ADL were performed. The association of ADL with dietary hardness score and the number of remaining teeth was determined.

Results

The mean dietary hardness score was 8.3 ± 2.6. Eighty individuals showed independence in ADL, whereas 156 individuals showed dependence. Logistic regression analysis, adjusted for potential confounding factors, showed that dietary hardness score was associated with ADL status but not the number of remaining teeth.

Conclusion

Our findings suggest that a low dietary hardness score is associated with dependence on ADL in 90‐year‐old individuals.

Histological and histomorphometric aspects of continual intermittent parathyroid hormone administration on osseointegration in osteoporosis rabbit model

In implant treatment, primary stability and osseointegration are improved by continual intermittent administration of parathyroid hormone (PTH) in patients with osteoporosis. However, the histological and histomorphometric aspects are not clear. The aim of this study was to investigate the histological and histomorphometric effects of intermittent PTH administration on osseointegration in a glucocorticoid-induced osteoporotic rabbit model. Fifteen female New Zealand rabbits were prepared for the osteoporosis model with ovariectomy and glucocorticoid administration. After 1 week, five rabbits were intermittently administered PTH for 8 weeks until the end point (PTHa group) and five for 4 weeks until implant placement (PTHb group). The remaining rabbits were intermittently administered saline for 8 weeks until the end point (Control group). Dental implants were inserted into the femoral epiphyses 11 weeks after ovariectomy. After 4 weeks, the maximum removal torque (RT) of the placed implant and bone implant contact (BIC) ratio were evaluated. In addition micro-computed tomography and histomorphometric analyses were performed. The RT and BIC values were significantly higher in the PTHa group compared with those of the PTHb and Control groups (p< 0.05). Furthermore, the bone mineral densities and Hounsfield units were significantly higher in the PTHa group than those in the PTHb and Control groups. Histologic and histomorphometric measurements revealed that continuous administration of PTH improved bone density and bone formation around the implant placement site, as well as systemic bone formation. Therefore, favorable implant stability was achieved under osteoporosis.

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.

CONCLUSION

Samples with 5 wt% CPC-Mont are potential candidates as antimicrobial adhesive polyurethane gel sheets for fastening facial and somato prostheses.

Nd:YVO4 laser groove treatment can improve the shear bond strength between dental PEEK and adhesive resin cement with an adhesive system

The purpose of this study was to investigate the effect of various surface treatments on the shear bond strength between dental polyetheretherketone (PEEK) and adhesive resin cement. Two hundred and forty specimens were randomly classified into four groups: no treatment, sandblasted, sulfuric-acid-etched, and laser-grooved treatment. Each group was classified into two adhesive resin cement subgroups. Surface roughness, water contact angle, shear bond strength, and failure mode were measured; SEM and XPS results were obtained. The data were statistically analyzed using one-way or two-way analysis of variance and Tukey's honest significant difference test (α=0.05). Laser-grooved PEEK surface showed regular grooves and carbonization by thermal degradation; the surface roughness as well as water contact angle of were the highest in all groups. Shear bond strength values were significantly higher in the laser-groove-treated and sulfuric-acid-etched groups. Laser-groove-treated specimens showed cohesive failure. Laser-grooved treatment can improve shear bond strength between PEEK and adhesive resin cement.

Relationship between Food Crushing and Oral Function in Older Adults Requiring Nursing Home Care: A Pilot Study

We investigated how jelly is crushed and examined the relationship between tongue pressure and tongue food crushing ability among older adults requiring nursing home care. Seventy-two participants were instructed to freely crush the test foods soft jelly (SJ) and hard jelly (HJ). We visually evaluated the crushability of the test food and identified the intraoral tissues (active sites) used to crush the test food. The active sites were consistent for all participants for both SJ and HJ, and they included the maxillary and mandibular teeth in 41 participants, teeth and residual ridges in 15 participants, maxillary and mandibular residual ridges in 10 participants, and tongue and palate in six participants. Two participants failed to crush the SJ; the active sites in both participants were the tongue and palate. No participant using the tongue and palate as active sites could crush the HJ. Furthermore, 64 participants could crush the SJ and 23 could crush the HJ using the tongue and palate. The cutoff value of the tongue pressure for crushability of the HJ was 22.0 kPa. Assessing tongue pressure and intraoral active sites involved in food crushing could help determine an appropriate diet for older adults requiring nursing home care.

Prosthodontic treatment can improve the ingestible food profile in Japanese adult outpatients

PURPOSE

To investigate the effect of prosthodontic treatment on the ingestible food profile in adult Japanese outpatients, and to identify the related risk factors that can deteriorate the profile.

METHODS

The participants were 277 outpatients who visited university-based specialty clinics in Japan for prosthodontic treatment. The demographic data, number of present teeth assessed via intraoral examination, and oral health-related quality of life assessed by the total Oral Health Impact Profile (OHIP-J54) scores of all participants were recorded before treatment. Ingestible food profile score (IFS) was recorded using a validated food intake questionnaire. Eligible participants who answered the questionnaire before and after treatment were categorized into five groups based on the prosthodontic treatments they received (i.e., crowns, bridges, removable partial dentures, removable complete dentures, and removable complete and partial dentures).

RESULTS

Multivariate analysis of covariance revealed a statistically significant main effect of prosthodontic intervention (time course: before and after treatment) on mean IFS (P=0.035, F=4.526), even after adjusting for covariates (age, number of present teeth, and treatment modality). Multiple linear regression analysis revealed that the low number of present teeth (r=0.427, P<0.001) and a high OHIP-J54 total score (r=-0.519, P<0.001) of the patients at the baseline were significantly associated with their baseline IFSs, even after adjusting for confounding variables.

CONCLUSIONS

The findings of this multicenter follow-up study indicate the importance of prosthodontic rehabilitation in improving patients' ingestible food profiles.

Oral hypofunction and its relation to frailty and sarcopenia in community-dwelling older people

OBJECTIVE

The purpose of this study was to examine the frequency of oral hypofunction in community-dwelling older people and determine its relationship with frailty and sarcopenia.

BACKGROUND

Previous studies have shown that frailty and sarcopenia are associated with decreased oral function. However, these studies have only evaluated frailty or sarcopenia alone and have not evaluated their relationship with each other.

MATERIALS AND METHODS

The participants were community-dwelling independent older people in Kyoto. Their oral function evaluation included seven items (oral hygiene, oral dryness, occlusal force, tongue-lip motor function, tongue pressure, masticatory function and swallowing function). Oral hypofunction was defined as abnormalities in at least three of these items. The frailty status was classified into three categories (robust, pre-frail and frail) according to the frailty phenotype and deficit-accumulation models. Sarcopenia was defined according to the Asian Working Group for Sarcopenia (AWGS) Consensus. The relationships between oral function and frailty were analysed using logistic regression analyses, after adjusting for sarcopenia.

RESULTS

Among the 340 participants that were analysed (69 men, 271 women; average age: 75.0 years), 182 (53.5%) had oral hypofunction (40 men, 142 women; average age: 76.8 years). There was a significant relationship between oral hypofunction and deficit-accumulation model-assessed frailty, after adjusting for sarcopenia.

CONCLUSION

Almost half of the community-dwelling older people have oral hypofunction, which is significantly related to comprehensive frailty and sarcopenia.

Controlled release, antimicrobial activity, and oral mucosa irritation of cetylpyridinium chloride-montmorillonite incorporated in a tissue conditioner

This study examined the controlled release of cetylpyridinium chloride (CPC) from a tissue conditioner (TC) containing CPC-montmorillonite (CPC-Mont), the associated antimicrobial activity, and oral mucosa irritation. The CPC release test was performed daily for 28 days in three test solutions: distilled water, 0.2 M NaCl, and 0.2 M HCl. The antimicrobial activities for 7, 14, 21, and 28 days against Candida albicans, Staphylococcus aureus, and Streptococcus mutans were assessed according to the JIS Z 2801/ISO 22196 standard. An oral mucosa irritation test was conducted using cheek pouches in five male hamsters according to the ISO 10993-10:2010 standard. The amount of CPC released each day and the cumulative amount released over 28 days (6.12 mg) were less than the daily safe maximum of sore throat medicines (8 mg). Additionally, TC with CPC-Mont could sustain antimicrobial activity against adherent bacteria for 14 days and has no oral mucosa irritation potential.

Generalized periodontitis treated with periodontal, orthodontic, and prosthodontic therapy: A case report

BACKGROUND

Generalized periodontitis is a severe periodontal disease characterized by rapid periodontal destruction in healthy persons. This case report describes the treatment of a severe crowding, large overjet, and occlusal collapse due to the loss of anterior guidance with generalized periodontitis.

CASE SUMMARY

A 35-year-old female patient with a chief complaint of crowding and maxillary protrusion was diagnosed with generalized periodontitis by clinical and radiographic examinations. To improve crowding and overjet, orthodontic treatment was performed after basic periodontal therapy. Severely damaged upper right lateral incisor and left canine were extracted, and lower right first premolar and left second premolar were also removed to treat severe crowding. After orthodontic treatment, periodontal flap surgery for upper left molars and guided tissue regeneration for the lower left second molar was performed. Then, a dental implant was inserted in the upper left canine legion. The esthetics of the maxillary anterior tooth was improved by prosthetic restorations. The treatment result showed a well-improved occlusion with proper anterior guidance and healthy periodontal tissue after a retention period of 10 years.

CONCLUSION

Periodontal, orthodontic, and prosthodontic treatments are extremely useful to improve function and stable periodontal tissue for generalized periodontitis.

Osseointegration Aspects of Implants at the Bone Reconstruction Site by a Novel Porous Titanium Scaffold

OBJECTIVES

Porous titanium is used for the reconstruction of large bone defects due to its excellent mechanical strength. The quality of osseointegration of implants placed in bone reconstructed with porous titanium is unknown. The purpose of this in vivo study was to evaluate the osseointegration of implants at sites reconstructed using porous titanium.

MATERIAL AND METHODS

Hollow porous titanium (Ti) (outer-diameter 6 mm, inner-diameter 2 mm, length 4 mm, 85% porosity) and similar-sized porous hydroxyapatite (porous HA: 75% porosity) samples were prepared and implanted in 6 New Zealand white rabbit femurs. Four weeks later, an implant bed was created to receive a Ti implant (diameter 2 mm, length 4 mm). An implant placed at a pristine bone site served as the control. Four weeks later, histological and histomorphometric evaluations of the test and control sites were conducted.

RESULTS

Osseointegration was observed in all groups. There was no significant difference in the bone formation ratio and bone-implant contact (BIC) ratio across all groups for the whole area. At the cancellous bone area of the bone defect, superior bone formation ratio and BIC ratio were observed with porous Ti and porous HA compared to the control (bone formation ratio: control 1.8 [SD 3]%, HA 23 [SD 3]%, Ti 23.6 [SD 5]%; BIC ratio: control 5.4 [SD 5.3]%, HA 28.9 [SD 10.7]%, Ti 41.6 [SD 14]%). Porous Ti demonstrated good osteoconduction and osseointegration abilities, similar to porous HA.

CONCLUSIONS

To our knowledge, this is the first report of implant treatment after preliminary bone reconstruction using a titanium biomaterial. Porous titanium is a suitable material for bone reconstruction before implant treatment in load-bearing areas that allow subsequent prosthetic treatment.

Use of an intraoral scanner to evaluate oral health

The purpose of this study was to determine if intraoral scanners (IOS) are useful for dental hygiene instruction. The dental plaque of eight volunteers with healthy dentition was stained with a plaque-disclosing solution, and the O'Leary Plaque Control Record (PCR) was measured by direct observation and by evaluating IOS images. PCR values were higher for IOS images than for direct observation. The difference was greatest for the lingual surface of mandibular anterior teeth. Use of IOS for dental plaque examination might be useful as a novel method for dental hygiene instruction.

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.

A web-based survey of denture adhesive use among denture wearers 40 years of age and older

The purpose of this study was to clarify the usage and understanding of denture adhesives among 1,825 denture wearers, aged 40 years and older in Japan, using a web-based survey. The NTTCom Online survey (a closed investigation) was conducted over a period of 4 days using a 13-item questionnaire about denture adhesives. Results showed that 67.1% of the respondents were satisfied with their dentures; 81.5% of respondents knew about denture adhesive, but only 347 (19.0%) had used the product. Products used by the 347 denture wearers included cream type (79.7%), cushion type (16.2%), and powder type (3.2%). The most common reason for the selection of a particular type was "Saw the product" (59.9%), followed by "Saw an advertisement" (19.3%), and "Explanation at a dental clinic" (8.4%). The response of "Ill-fitting denture" significantly affected the response of "Use of denture adhesives" (chi-square test; P < 0.001). Moreover, the sensitivity (0.56) was lower than the specificity (0.75). These findings show that denture adhesives were not always necessary for those with ill-fitting dentures.

Bone turnover markers to assess jawbone quality prior to dental implant treatment: a case-control study

Background

Bone quality is as important as bone mineral density in terms of bone strength. Bone turnover markers (BTMs) are clinical indicators of bone quality. In implant dentistry, bone quality is considered equivalent to bone density on radiographic assessments. The purpose of this study was to determine whether the BTM values are reflected in jawbone condition by evaluating the relationship at baseline and during follow-up in patients with prosthodontic implants.

Computed tomography (CT) scans were obtained and BTM (osteocalcin, bone-specific alkaline phosphatase, pyridinoline cross-linked carboxyterminal telopeptide of type I collagen, and crosslinked N-telopeptide of type I collagen) levels in blood samples were measured in partially edentulous eighteen patients before implant surgery. During the follow-up observation after implant surgery, marginal bone loss (MBL) was measured on dental radiography. We investigated the relationship between the presence of BTM abnormalities and radiographic bone density.

Results

More women than men had abnormal BTM values. Bone turnover was accelerated in the group of women with abnormal BTM values. The density of cancellous bone at the implant placement site was significantly lower in the patients with abnormally high BTM values than in their counterparts with BTM values in the normal range.

Conclusions

Female patients who undergo implant treatments may have reduced bone quality; evaluations of bone strength will require assessments of both BTMs and the density of cancellous bone.

Association between masticatory ability and oral functions

Background

Mastication is the process of breaking ingested food with the teeth and mixing it with saliva to form a mass that is easy to swallow. However, few studies have reported on oral functions, such as occlusal force, tongue pressure, and mastication. The purpose of this study was to evaluate the association between masticatory function and oral functions, such as occlusal force and tongue pressure.

Material and Methods

In this study, there were 113 patients (41 men and 72 women; mean age, 68.4 ± 11.3 years) who visited dentists at the Hiroshima University Hospital, Hiroshima, Japan between April 2015 and November 2018. Masticatory function of the patients was evaluated using a masticatory ability test system. In addition, occlusal force was measured using a pressure-sensitive film and the maximum tongue pressure was measured with a tongue pressure measuring device according to a conventional method. The relationship of masticatory ability with occlusal force and tongue pressure was examined using multivariate analysis while considering patients’ age, gender, and the number of remaining teeth.

Results

Masticatory ability was significantly related to occlusal force, maximum tongue pressure, age, body mass index, the number of remaining teeth, and occlusal contact area (p< 0.05). Multiple regression analysis identified that masticatory ability was significantly associated (p< 0.05) with occlusal force and maximum tongue pressure.

Conclusions

Masticatory ability was significantly associated with occlusal force and maximum tongue pressure, indicating that the large muscle mass in the oral cavity is indispensable for improving masticatory function.

Key words:Mastication, tongue pressure, occlusion force, oral function.

Delayed Swallowing Reflex is Overlooked in Swallowing Screening Among Acute Stroke Patients

BACKGROUND AND PURPOSE

Dysphagia in the acute phase of stroke contributes significantly to poor outcomes and is associated with the development of aspiration pneumonia and malnutrition. Therefore, an accurate evaluation of swallowing is necessary before initiating oral food intake. The modified water swallow test (MWST) and the repetitive saliva swallow test (RSST) are commonly used as bedside screening methods for swallowing dysfunction, but it is unclear whether other factors contribute to dysphagia and consequent aspiration. The purpose of this study was to identify characteristics that might be overlooked in screening tests.

METHODS

Participants were prospectively selected from patients hospitalized for stroke at the Suiseikai Kajikawa Hospital between August 1, 2016 and June 30, 2018. Inclusion criteria were conscious and stable medical condition, and patients who were diagnosed with dementia were excluded. A videofluoroscopic (VF) swallowing study was carried out on all patients who met the inclusion/exclusion criteria and who passed both the MWST and the RSST.

RESULTS

Aspiration was observed in 16 of 172 patients (9.3%) when swallowing 3 ml of water. These aspirated patients showed significantly delayed swallowing reflex on VF.

CONCLUSIONS

Swallowing evaluation using a combination of the MWST and the RSST is reasonably effective. However, patients who show a delayed swallowing reflex might be overlooked by this screening procedure.

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.

Development of a novel bioactive titanium membrane with alkali treatment for bone regeneration

This study evaluates a bioactive titanium membrane with alkali treatment for stimulating apatite formation and promoting bone regeneration. The titanium thin membranes were either treated with NaOH (alkali-group) or untreated (control). Each sample were incubated in simulated body fluid. Subsequently, the composition of the surface calcium deposition, its weight increase ratio, and optical absorbance were evaluated. Then, the bone defect was trephined on the rats calvaria and covered with each sample membrane or no membrane, and the bone tissue area ratio (BTA) and bone membrane contact ratio (BMC) were evaluated. The spherical crystalline precipitates formed in both groups. In the alkali-group after 21 days, the precipitates matured, forming apatite-like precipitates. The alkali-group showed higher Ca and P contents and weight increase ratios than the control. The alkali-group exhibited a higher BMC than the control in the central area. Thus, this novel membrane has high apatite-forming and bone regeneration abilities.

IL-6 Induced by Periodontal Inflammation Causes Neuroinflammation and Disrupts the Blood-Brain Barrier

Background: Periodontal disease (PD) is a risk factor for systemic diseases, including neurodegenerative diseases. The role of the local and systemic inflammation induced by PD in neuroinflammation currently remains unclear. The present study investigated the involvement of periodontal inflammation in neuroinflammation and blood–brain barrier (BBB) disruption. Methods: To induce PD in mice (c57/BL6), a ligature was placed around the second maxillary molar. Periodontal, systemic, and neuroinflammation were assessed based on the inflammatory cytokine mRNA or protein levels using qPCR and ELISA. The BBB permeability was evaluated by the mRNA levels and protein levels of tight junction-related proteins in the hippocampus using qPCR and immunofluorescence. Dextran tracing in the hippocampus was also conducted to examine the role of periodontal inflammation in BBB disruption. Results: The TNF-α, IL-1β, and IL-6 levels markedly increased in gingival tissue 1 week after ligation. The IL-6 serum levels were also increased by ligature-induced PD. In the hippocampus, the IL-1β mRNA expression levels were significantly increased by ligature-induced PD through serum IL-6. The ligature-induced PD decreased the claudin 5 expression levels in the hippocampus, and the neutralization of IL-6 restored its levels. The extravascular 3-kDa dextran levels were increased by ligature-induced PD. Conclusions: These results suggest that the periodontal inflammation-induced expression of IL-6 is related to neuroinflammation and BBB disruption in the hippocampus, ultimately leading to cognitive impairment. Periodontal therapy may protect against neurodegenerative diseases.

Association between salivary alpha-amylase and subjective and objective oral parafunctions in community-dwelling elderly individuals

Background/purpose

Stress in the elderly is caused by loss of physical and psychological health. Although there have been many reports on the intraoral environment affecting physical health, few reports exist on stress and the intraoral environment in the elderly. The aim of this study was to investigate the relationship between salivary α-amylase as an index of stress value and the intraoral environment.

Materials and methods

Three hundred and nineteen participants were community-dwelling independent individuals over 65 years old. The outcome variable was salivary α-amylase. After measurement, salivary α-amylase was classified into four groups (0 = 0–30, 1 = 31–45, 2 = 46–60, 3 = 61–200). The predictor variables were physical status (which includes age and male body-mass index) and subjective and objective symptoms (which include present teeth, torus palatinus, torus mandibularis, temporomandibular joint noise, bruxism, and dental attrition). These variables were compared among participants using univariate analysis and multiple logistic regression analysis.

Results

The participants included 77 men and 242 women, with a mean age of 75.8 ± 5.4 years (65–94 years). Although temporomandibular joint noise and dental attrition were significantly positively correlated with salivary α-amylase, bruxism was significantly negatively correlated with salivary α-amylase (p < 0.05). Stepwise regression analysis revealed a significant relationship between salivary α-amylase and temporomandibular joint noise, bruxism, and dental attrition.

Conclusion

High salivary α-amylase is associated with a high rate of temporomandibular joint noise and dental attrition, and a low rate of bruxism among elderly participants.

Improper sitting posture while eating adversely affects maximum tongue pressure

Background/purpose

Although many studies have examined the efficacy of neck and trunk positioning during eating, few studies have examined how the positioning of the lower extremities affects swallowing function. The purpose of this study was to examine how tongue pressure, which is an important factor during swallowing, is affected by eating postures in bed and wheelchair.

Materials and methods

A total of 43 healthy adults (13 men and 30 women; 29.0 ± 5.9 years) and 33 elderly individuals requiring long-term care (14 men and 19 women; 83.6 ± 7.8 years) participated.

In both healthy and elderly participants, tongue pressure was measured in four different postures: a good and poor postures in bed (postures 1 and 2, respectively), and a good and poor postures in a reclining wheelchair (posture 3 and 4, respectively).

Results

Among the healthy participants, the mean tongue pressure was significantly higher in posture 1 (40.2 ± 7.24 kPa) than in posture 2 (37.6 ± 8.68 kPa) or posture 4 (38.2 ± 8.14 kPa) (P < 0.05). Tongue pressure was also significantly higher in posture 3 (41.3 ± 7.75 kPa) than in either posture 2 or 4 (P < 0.05).

Among the elderly participants, the median tongue pressure in posture 1 (16.9 kPa; interquartile range [IQR], 9.4–21.6 kPa) was significantly higher than that in posture 2 (14.1 kPa; IQR, 9.2–21.6 kPa). Tongue pressure in posture 3 (18.5 kPa; IQR, 14.2–26.0 kPa) was significantly higher than that in either posture 1 or 2, and posture 4 (15.9 kPa; IQR, 10.6–22.9 kPa).

Conclusion

Posture during eating can potentially affect tongue pressure.

Five-year change in maximum tongue pressure and physical function in community-dwelling elderly adults

Background/purpose

To identify age-related changes in maximum tongue pressure (MTP), it is necessary to determine individual biological age. The fitness age score (FAS) is used to calculate the biological age, based on the one-leg standing time with eyes open, vertical jump height, grip strength, functional reach, and 10-m walk time.

Materials and methods

The study included 112 community-dwelling elderly adults (42 males and 70 females). We investigated MTP, FAS, and body mass index (BMI) at baseline and 5 years later. MTP was determined with a pressure measurement device.

Results

A significant reduction in MTP, FAS, and BMI in both male and female subjects was observed at 5 years. A negative correlation between change in MTP and baseline MTP was observed, but there was no correlation between MTP change and baseline FAS, BMI, and change in FAS and BMI.

Conclusion

Age-related decline in MTP might be associated with high MTP, reflecting decreased reserve. Additionally, age-related decline in tongue function might be different from that of physical function.

Comparison of the Iowa Oral Performance Instrument and JMS tongue pressure measurement device

Background/purpose

Tongue pressure measurement conveys important information about eating and swallowing function. The Iowa Oral Performance Instrument® (IOPI) and KAY Swallowing Workstation® are internationally used for tongue pressure measurement, but for legal reasons cannot be used in Japan; rather the JMS tongue pressure measurement device® has been approved for use in Japan. However, it is not clear whether measurement obtained with these devices are directly comparable.

Materials and methods

This study investigated the correlation between the maximum tongue pressure data measured by the IOPI and the JMS tongue pressure measurement device in young healthy participants (34 males; 23.2 ± 2.0 years old, and 40 females; 21.4 ± 1.3 years old).

Results

Measurements obtained with these two devices showed significant correlations in the total cohort, and in male and female participants, separately (P < 0.05).

Conclusion

These findings demonstrate that the measurements obtained with the JMS device is comparable to those obtained with the IOPI. In Japan, JMS tongue pressure measurement device is used not only in dysphagia research field, but also geriatrics field, and extensive and detailed investigations has been carried out.

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.

Comparative Study of Surface Modification Treatment for Porous Titanium

OBJECTIVES

This study was to investigate suitable surface treatment methods for porous titanium by ex vivo study of material properties and calcium phosphate deposition in simulated body fluid.

MATERIAL AND METHODS

Porous titanium with acid (H2SO4 and HCl mixed acid) or alkali (NaOH) treatment was prepared. The surfaces were observed, and the weight change ratio (after and before surface treatment) and compression strength were measured. To investigate the apatite formation ability, each sample was immersed in simulated body fluid (SBF). Surface observations were performed, and the weight change ratio (before/after immersing SBF) and calcification (by alizarin red staining) were measured.

RESULTS

The acid group showed a martensitic micro-scale rough structure and the weight and mechanical strength greatly decreased compared to the other groups. The alkali group exhibited a nano-scale roughness structure with similar weight and mechanical strength. Following immersion in SBF, an apatite-like crystal layer in the alkali group was observed. The weight of all samples increased. The change in weight of the samples in the alkali, acid, and control groups were significantly different, showing the following trend: alkali group (1.6%) > acid group (1.2%) > control group (0.8%). Calcium precipitation values were higher in the samples from alkali group than in those from the acid and control groups.

CONCLUSIONS

Alkali treatment was found to be a suitable surface modification method for porous titanium, resulting in good mechanical strength and apatite formation ability in simulated body fluid.

Oral colonisation by antimicrobial-resistant Gram-negative bacteria among long-term care facility residents: prevalence, risk factors, and molecular epidemiology

Background

For residents of long-term care facilities (LTCFs), antimicrobial-resistant bacteria (ARB) are a risk factor, yet their oral colonisation, potentially leading to aspiration pneumonia, remains unclear. This study was undertaken to survey the prevalence, phenotypic characteristics, and molecular epidemiology of antimicrobial-resistant Gram-negative bacteria in the oral cavity of LTCF residents, and to analyse the risk factors for such carriers.

Methods

This study involved 98 residents of a LTCF in Hiroshima City, Japan, aged between 55 and 101 years. Oropharyngeal swabs were collected and plated on screening media for ESBL-producing and carbapenem-resistant bacteria; isolates were identified and tested for antibiotic susceptibility; biofilm formation was tested in vitro; identification of epidemic clones were pre-determined by PCR; resistance genes, sequence types, and whole-genome comparison of strains were conducted using draft genome sequences. Demographic data and clinical characterisations were collected and risk factors analysed.

Results

Fifty-four strains from 38% of the residents grew on screening media and comprised predominantly of Acinetobacter spp. (35%), Enterobacteriaceae spp. (22%), and Pseudomonas spp. (19%). All Escherichia coli isolates carried CTX-M-9 group and belonged to the phylogroup B2, O25:H4 ST131 fimH30 lineage. Six Acinetobacter baumannii isolates presented identical molecular characteristics and revealed more biofilm production than the others, strongly suggesting their clonal lineage. One Acinetobacter ursingii isolate displayed extensive resistance to various ß-lactams due to multiple acquired resistance genes. One Pseudomonas aeruginosa isolate showed exceptional resistance to all ß-lactams including carbapenems, aminoglycosides, and a new quinolone, showing a multidrug-resistant Pseudomonas aeruginosa (MDRP) phenotype and remarkable biofilm formation. Genome sequence analysis revealed this isolate was the bla_IMP-1-positive clone ST235 in Japan. Strokes (cerebral infarction or cerebral haemorrhage) and percutaneous endoscopic gastrostomy tubes were recognised as risk factors for oral colonisation by ARB in the LTCF residents.

Conclusions

ARB, as defined by growth on screening agar plates, which carried mobile resistance genes or elements or conferred high biofilm formation, were already prevalent in the oral cavity of LTCF residents. Health-care workers involved in oral care should be aware of antimicrobial resistance and pay special attention to transmission prevention and infection control measures to diminish ARB or mobile resistance elements dissemination in LTCFs.

Development of tissue conditioner containing cetylpyridinium chloride montmorillonite as new antimicrobial agent: Pilot study on antimicrobial activity and biocompatibility

PURPOSE

The mechanical properties, antimicrobial activity, and biocompatibility of a novel antimicrobial tissue conditioner containing cetylpyridinium chloride with montmorillonite (CPC-Mont) were evaluated.

METHODS

To examine the mechanical properties of the novel material, hardness, consistency, and penetration tests were conducted. Antimicrobial activity against Candida albicans (C. albicans) and Staphylococcus aureus (S. aureus) was evaluated. Cell viabilities of fibroblasts and epithelial cells using eluates from materials were measured to evaluate cytotoxicity. In addition, to assess tissue response, animal experiments were conducted.

RESULTS

The hardness test results were similar to those of other commercially available materials. The novel tissue conditioner showed good antimicrobial activity against C. albicans and S. aureus compared with other materials. This effect was sustained for a week for C. albicans. In the case of S. aureus, microbial growth was suppressed for up to 3 weeks. Cell viability of the novel material for the eluate at 1 day was significantly less than those of other material for both cells. However, the cell viability at 7 days showed no significant difference. Animal experiments demonstrated that inflammatory responses around materials were not observed on the oral mucosa as other material.

CONCLUSION

Within the limitations of this in vitro and in vivo study, the results suggest that the newly developed tissue conditioner containing CPC-Mont has not only excellent antimicrobial properties, but also the same mechanical properties and biocompatibility as tissue conditioners on the market.

The development of novel bioactive porous titanium as a bone reconstruction material

Porous titanium fabricated by the resin-impregnated titanium substitute technique has good mechanical strength and osteoconduction. The alkali treatment of the titanium surface creates a bioactive surface. Alkali-treated porous titanium is expected to accelerate bone formation. The purpose of this study was to evaluate the bone reconstruction ability of alkali-treated porous titanium. Porous titanium (85% porosity) was treated with an alkali solution (5 N NaOH, 24 h). To assess material properties, we analyzed the surface structure by scanning electron microscopy (SEM) and mechanical strength testing. To assess bioactivity, each sample was soaked in a simulated body fluid (Hank's solution) for 7 days. Surface observations, weight change ratio measurement (after/before being soaked in Hank's solution) and surface elemental analysis were performed. We also designed an in vivo study with rabbit femurs. After 2 and 3 weeks of implantation, histological observations and histomorphometric bone formation ratio analysis were performed. All data were statistically analyzed using a Student's t-test (P < 0.05) (this study was approved by the Hiroshima University animal experiment ethics committee: A11-5-5). Non-treated porous titanium (control) appeared to have a smooth surface and the alkali-treated porous titanium (ATPT) had a nano-sized needle-like rough surface. ATPT had similar mechanical strength to that of the control. After soaking into the Hank's solution, we observed apatite-like crystals in the SEM image, weight gain, and high Ca and P contents in ATPT. There was significant bone formation at an early stage in ATPT compared with that in control. It was suggested that the alkali-treated porous titanium had a bioactive surface and induced bone reconstruction effectively. This novel bioactive porous titanium can be expected to be a good bone reconstruction material.

Porous titanium fabricated by the resin-impregnated titanium substitute technique has good mechanical strength and osteoconduction.

Oral function and vertical jump height among healthy older people in Japan

OBJECTIVE

Vertical jump height and oral function affect the general muscle condition. This study aimed to evaluate the association between vertical jump height and oral function among healthy older individuals.

BASIC RESEARCH DESIGN

Cross-sectional analytic study.

PARTICIPANTS

231 independent older people (mean age, 74.4 ± 5.6 years) who participated in the Kyoto Elders Physical Fitness Measurement Research Project. Individuals with partial or complete edentulousness who did not use a prosthetic device or complained of oral/maxillofacial pain were excluded from the study.

INTERVENTIONS

Grip strength was measured using a Smedley Hand Dynamometer. To measure masticatory performance, the participants were instructed to chew a gummy jelly on their habitual chewing side (left or right) for 20 s. Occlusal force, contact area, and pressure were also assessed.

MAIN OUTCOME MEASURES

The outcome variable was vertical jump height. The predictor variables were physical status (age, body mass index, and grip strength), oral status (number of present teeth and denture use), and oral function (masticatory performance, occlusal force, occlusal contact area, occlusal pressure, and tongue pressure). These relationships were evaluated with univariate analysis, and then multiple regression analysis was performed with age as the covariate for each male and female participant.

RESULTS

Vertical jump height was significantly associated with grip strength in both men and women. Moreover, in women, it was associated with masticatory performance, occlusal force, and occlusal contact area.

CONCLUSIONS

Vertical jump height was closely associated with oral function among healthy older women.

Osteoclastogenesis from bone marrow cells during estrogen-induced medullary bone formation in Japanese quails

Osteoclasts are differentiated from hematopoietic mononuclear cells by regulation of the receptor activator of nuclear factor kappa-B (RANK)/receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) system. Medullary bone (MB) that forms in the bone marrow of female birds is remodeled under the control of circulating estrogen (E2) during the laying period. Although the osteoclasts of MB are differentiated from mononuclear cells, the mechanism of osteoclastogenesis is not known. We investigated whether MB osteoclastogenesis is regulated by the RANK/RANKL/OPG system using MB from male quails induced with E2. Bone marrow cells (BMCs) differentiate into osteoclasts that have the ability of bone resorption via stimulation of RANKL/M-CSF, but this ability is suppressed by OPG and differentiation is inhibited by calcinurin inhibitors. We found that BMCs at 3 days after E2 administration had high bone osteoclastogenesis ability and colony forming unit-granulocyte/macrophage (CFU-GM)/colony forming unit-macrophage (CFU-M) formation abilities. We conclude that MB osteoclasts are differentiated from BMCs by the RANK/RANKL/OPG system, and that precursor cells of osteoclasts are increased during MB formation.

Association between buccal mucosa ridging and oral feature/symptom and its effects on occlusal function among dentate young adults in a cross-sectional study of Japan

Objective: The purpose of this study was to assess the distinction in oral features/symptoms and occlusal function between young dentate individuals with and without buccal mucosa ridging (BMR). Methods: This cross-sectional study included 200 young adults. The outcome variable was BMR state. The predictor variables were oral features/symptoms (torus palatinus, torus mandibularis, temporomandibular joint noise, bruxism, tongue thrusting habit, number of teeth present, and occlusal vertical dimension) and oral function (occlusal force, occlusal contact area, occlusal pressure, tongue pressure). These variables were compared among participants with and without BMR using univariate and multiple logistic regression analysis. Results: There were 119 participants with BMR and 81 without BMR. Multiple logistic regression analysis revealed that BMR was closely associated with bruxism, occlusal vertical dimension, and occlusal pressure. Discussion: Oral/occlusal changes of increased bruxism, lower occlusal vertical dimension, and lower occlusal pressure constitute the major causes of BMR.

Novel fabrication of porous titanium by a resin-impregnated titanium substitution technique for bone reconstruction

The purpose of this study was to evaluate the characteristic structures and osteoconduction ability of porous titanium structures using a resin-impregnated titanium substitution fabrication technique.

Palatal augmentation prosthesis (PAP) can improve swallowing function for the patients in rehabilitation hospital

PURPOSE

The aim of this study was to clarify the effects of fitting palatal augmentation prosthesis (PAP) on the swallowing function for the patients in rehabilitation hospital.

METHODS

The subjects included 18 elderly hospitalized patients whose body mass index was <18.5kg/m². All subjects wore maxillary complete denture. During a videofluoroscopic examination in which the patients were asked to swallow, post-swallowing pyriform sinus residue was detected. The subjects' maxillary dentures were then modified into PAPs by recording tongue movement in the palatal region. The resulting swallowing dynamics were evaluated qualitatively and quantitatively before and after fitting the PAP.

RESULTS

We found that fitting the PAP resulted in the resolution of aspiration in two patients and disappearance of pharyngeal residue in three. The pharyngeal delay and transit times were significantly shortened.

CONCLUSIONS

These results demonstrated that PAPs could be beneficial treatment devices that may reduce post-swallowing pharyngeal residue formation due to decreased muscle strength.