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.

Portable dielectrophoresis for biology: ADEPT facilitates cell trapping, separation, and interactions

Dielectrophoresis is a powerful and well-established technique that allows label-free, non-invasive manipulation of cells and particles by leveraging their electrical properties. The practical implementation of the associated electronics and user interface in a biology laboratory, however, requires an engineering background, thus hindering the broader adoption of the technique. In order to address these challenges and to bridge the gap between biologists and the engineering skills required for the implementation of DEP platforms, we report here a custom-built, compact, universal electronic platform termed ADEPT (adaptable dielectrophoresis embedded platform tool) for use with a simple microfluidic chip containing six microelectrodes. The versatility of the open-source platform is ensured by a custom-developed graphical user interface that permits simple reconfiguration of the control signals to address a wide-range of specific applications: (i) precision positioning of the single bacterium/cell/particle in the micrometer range; (ii) viability-based separation by achieving a 94% efficiency in separating live and dead yeast; (iii) phenotype-based separation by achieving a 96% efficiency in separating yeast and Bacillus subtilis; (iv) cell-cell interactions by steering a phagocytosis process where a granulocyte engulfs E. coli RGB-S bacterium. Together, the set of experiments and the platform form a complete basis for a wide range of possible applications addressing various biological questions exploiting the plug-and-play design and the intuitive GUI of ADEPT.

Efficacy of Low-Level Laser Therapy for Oral Mucositis in Hematologic Patients Undergoing Transplantation: A Single-Arm Prospective Study

Oral mucositis significantly affects the quality of life in hematologic cancer patients undergoing hematopoietic stem cell transplantation. Despite global evidence supporting the efficacy of low-level laser therapy (LLLT) for mucositis prevention, its clinical adoption in Japan is limited. This study aimed to fill this gap by evaluating the safety and efficacy of LLLT in a Japanese patient population. In a single-group, non-blinded, exploratory trial, we compared 21 LLLT-treated patients against a historical control of 96 patients. The primary endpoint was the incidence of Grade ≥ 2 mucositis, based on NCI-CTCAE ver. 4.0. The LLLT group showed a significantly lower incidence of Grade ≥ 2 mucositis (23.8%) compared to the control group (64.6%) (p = 0.0006). Furthermore, Grade ≥ 2 mucositis correlated with increased oral dryness and longer hospital stays. Our study confirms the efficacy of LLLT in reducing the onset of severe oral mucositis among Japanese hematologic cancer patients, advocating for its clinical introduction as a preventive measure in Japan.

Head and neck cancer patients show poor oral health as compared to those with other types of cancer

PURPOSE

Several studies have found associations between periodontitis and various types of cancer. Since the site of head and neck cancer (HNC) has contiguity or proximity to the oral cavity, it may be particularly influenced by oral inflammation. This study aimed to determine whether HNC patients have poor oral health as compared to those with other types of cancer.

METHODS

This study retrospectively examined oral environmental factors including periodontal inflamed surface area (PISA), a new periodontal inflammatory parameter. A total of 1030 cancer patients were divided into the HNC (n = 142) and other cancer (n = 888) groups. Furthermore, the HNC group was divided into high (n = 71) and low (n = 71) PISA subgroups, and independent risk factors affecting a high PISA value were investigated.

RESULTS

Multivariate logistic regression analysis showed that number of missing teeth (odds ratio 1.72, 95% CI 1.15-2.56, P < 0.01), PISA (odds ratio 1.06, 95% CI 1.03-1.06, P < 0.05), and oral bacterial count (odds ratio 1.02, 95% CI 1.01-1.03, P < 0.01) were independent factors related to HNC. In addition, multivariate logistic regression analysis indicated that current smoker (odds ratio 7.51, 95% CI 1.63-34.71, P < 0.01) and presence of untreated dental caries (odds ratio 3.33, 95% CI 1.23-9.00, P < 0.05) were independent risk factors affecting high PISA values in HNC patients.

CONCLUSION

HNC patients have higher levels of gingival inflammation and poor oral health as compared to patients with other types of cancer, indicating that prompt oral assessment and an effective oral hygiene management plan are needed at the time of HNC diagnosis.

Correlation Between Bacteria Count Using a Rapid Bacterium Counting System and Changes in Wound Area on Diabetic Foot Ulcers in Indonesia: A Prospective Study

This study aimed to clarify the correlation between changes in bacterial number and wound area in diabetic foot ulcers (DFUs). This study used a prospective longitudinal cohort design. A total of 30 participants met the inclusion criteria. Changes in bacterial number and wound area were evaluated weekly until week 4. The chi-square test indicated no significant correlation between biofilm formation and wound area (p = 0.32) but a significant correlation between bacterial count and wound area (p = 0.05). Logistic regression analysis showed a significant correlation between bacterial count and changes in wound area (odds ratio, 0.60; 95% confidence interval [CI], 0.372-0.997; p = 0.04). The receiver operating characteristic analysis showed an area under the curve of 0.660 (95% CI, 0.52-0.79; p = 0.03) with a sensitivity of 97% and specificity of 88%. The present prospective longitudinal cohort study demonstrated the correlation between bacterial count changes and wound area in DFUs. Our results suggest that changes in bacterial count could help wound healing evaluations.

The Association of Dietary Intake, Oral Health, and Blood Pressure in Older Adults: A Cross-Sectional Observational Study

Hypertension is related to impaired mastication that causes malnutrition, declining the general health of older adults. This study assessed the role of dietary intake in the relationship between oral health and blood pressure. Eight hundred ninety-four adults aged ≥65 years who independently lived in rural regions of Japan participated in this study. Hypertension was classified according to the guidelines of the Japanese Society of Hypertension. The oral condition was evaluated by analyzing the remaining teeth, occlusal force, posterior occlusal support, masticatory performance, oral moisture, and oral bacterial level. Dietary intake was assessed using a brief self-administered dietary history questionnaire. Mann-Whitney U, chi-square, Kruskal-Wallis tests, and logistic regression analyses were used to elucidate the factors related to hypertension. Normotensive, hypertensive, and history of hypertension were observed in 30.9%, 23.8%, and 45.3% of the participants, respectively. The factors significantly associated with the hypertension were age, body mass index, posterior occlusal support condition, and sodium-to-potassium ratio related to salt intake and/or vegetable intake. Participants without posterior occlusion significantly had higher risk of hypertension (odds ratio = 1.72). This study suggested that there was an association between oral health and hypertension, while the loss of occlusal support may influence nutritional intake conditions.

Protease inhibitor concentrations in the saliva of individuals experiencing oral dryness

Background

Oral dryness is a common symptom that may interfere with swallowing, chewing, and taste. The most common reason for oral dryness is hyposalivation. Some individuals experiencing oral dryness do not have hyposalivation, however, and the reverse is also true. Here, we focused on healthy individuals with a lower salivary flow rate and evaluated the relationship between the perception of oral dryness and salivary parameters to clarify the cause underlying the perception of oral dryness.

Methods

A total of 59 participants were divided into 2 groups with a lower or higher salivary flow rate according to the median salivary flow rate. In participants with a lower salivary flow rate, we assessed salivary bacterial counts, protease activities, protein concentrations, oral parameters, and the subjective perception of oral dryness.

Results

Protease activities and concentrations of protease inhibitors such as cystatin-D and cystatin-SA in the saliva of participants experiencing oral dryness were significantly higher and lower, respectively, than in those not experiencing oral dryness, even though no difference in the salivary flow rate was detected. Salivary cystatin-D and cystatin-SA concentrations correlated negatively with salivary protease activities.

Conclusions

The composition of salivary protease inhibitors and increased protease activities affect the subjective perception of oral dryness.

A review: Dielectrophoresis for characterizing and separating similar cell subpopulations based on bioelectric property changes due to disease progression and therapy assessment

This paper reviews the use of dielectrophoresis for high-fidelity separations and characterizations of subpopulations to highlight the recent advances in the electrokinetic field as well as provide insight into its progress toward commercialization. The role of cell subpopulations in heterogeneous clinical samples has been studied to deduce their role in disease progression and therapy resistance for instances such as cancer, tissue regeneration, and bacterial infection. Dielectrophoresis (DEP), a label-free electrokinetic technique, has been used to characterize and separate target subpopulations from mixed samples to determine disease severity, cell stemness, and drug efficacy. Despite its high sensitivity to characterize similar or related cells based on their differing bioelectric signatures, DEP has been slowly adopted both commercially and clinically. This review addresses the use of dielectrophoresis for the identification of target cell subtypes in stem cells, cancer cells, blood cells, and bacterial cells dependent on cell state and therapy exposure and addresses commercialization efforts in light of its sensitivity and future perspectives of the technology, both commercially and academically.

Association between oral health status and oral food intake level in subacute stroke patients admitted to a convalescent rehabilitation unit

BACKGROUND

Stroke patients often suffer from dysphagia during their recovery. We hypothesised that subacute stroke patients with dysphagia had more deteriorated oral health status including muscle strength and motor function.

OBJECTIVE

Quantitatively investigate oral health status and identify associations with oral feeding status in stroke patients admitted to a convalescent rehabilitation unit.

METHODS

We prospectively recruited 187 stroke patients admitted to a convalescent rehabilitation unit. Oral feeding status was examined using the Functional Oral Intake Scale (FOIS), and the cohort was divided into three groups based on FOIS score as non-oral feeding (FOIS-123; 22 patients), dysphagic diet (FOIS-45; 74 patients), and regular diet (FOIS-67; 91 patients) groups. Activities of daily living (ADL) were assessed with the Functional Independence Measure (FIM). Oral health status was measured quantitatively in six oral function parameters and Oral Health Assessment Tool (OHAT), and differences according to the FOIS, age and FIM were statistically tested.

RESULTS

In bivariate analysis, two parameters, tongue pressure and tongue-lip motor functions were significantly higher in the regular diet group than in the other groups (P < .01). Gross OHAT score was also significantly better in the regular diet group than in the other groups (P < .01). These significant associations mostly remained in the multiple model after adjusting for age and FIM.

CONCLUSION

This study suggests that, amongst oral health status, tongue strength and motor function, as well as OHAT score, may have strong associations with oral feeding status in subacute stroke patients at convalescent rehabilitation units regardless of ADL levels.

Relationship between Oral Bacterial Count and Postoperative Complications among Patients with Cardiovascular Disease Treated by Surgery: A Retrospective Cohort Study

In this retrospective observational study, we evaluated the relationship between perioperative oral bacterial counts and postoperative complications in cardiovascular disease (CVD) patients. From April 2012 to December 2018, all patients scheduled for surgery received perioperative oral management (POM) by oral specialists at a single center. Tongue dorsum bacterial counts were measured on the pre-hospitalization day, preoperatively, and postoperatively. Background data were collected retrospectively. Among the 470 consecutive patients, the postoperative complication incidence rate was 10.4% (pericardial fluid storage, n = 21; postoperative pneumonia, n = 13; surgical site infection, n = 9; mediastinitis, n = 2; and seroma, postoperative infective endocarditis, lung torsion, and pericardial effusion, n = 1 each). Oral bacterial counts were significantly higher in the pre-hospitalization than in the pre- and postoperative samples (p < 0.05). Sex, cerebrovascular disease, and operation time differed significantly between complications and no-complications groups (p < 0.05). Multivariate analysis with propensity score adjustment showed a significant association between postoperative oral bacterial count and postoperative complications (odds ratio 1.26; 95% confidence interval, 1.00–1.60; p = 0.05). Since the development of cardiovascular complications is a multifactorial process, the present study cannot show that POM reduces complications but indicates POM may prevent complications in CVD patients.

A novel ultralow conductivity electromanipulation buffer improves cell viability and enhances dielectrophoretic consistency

Cell separation has become a critical diagnostic, research, and treatment tool for personalized medicine. Despite significant advances in cell separation, most widely used applications require the use of multiple, expensive antibodies to known markers in order to identify subpopulations of cells for separation. Dielectrophoresis (DEP) provides a biophysical separation technique that can target cell subpopulations based on phenotype without labels and return native cells for downstream analysis. One challenge in employing any DEP device is the sample being separated must be transferred into an ultralow conductivity medium, which can be detrimental in retaining cells' native phenotypes for separation. Here, we measured properties of traditional DEP reagents and determined that after just 1-2 h of exposure and subsequent culture, cells' viability was significantly reduced below 50%. We developed and tested a novel buffer (Cyto Buffer) that achieved 6 weeks of stable shelf-life and demonstrated significantly improved viability and physiological properties. We then determined the impact of Cyto Buffer on cells' dielectric properties and morphology and found that cells retained properties more similar to that of their native media. Finally, we vetted Cyto Buffer's usability on a cell separation platform (Cyto R1) to determine combined efficacy for cell separations. Here, more than 80% of cells from different cell lines were recovered and were determined to be >70% viable following exposure to Cyto Buffer, flow stimulation, electromanipulation, and downstream collection and growth. The developed buffer demonstrated improved opportunities for electrical cell manipulation, enrichment, and recovery for next generation cell separations.

Methods of Generating Dielectrophoretic Force for Microfluidic Manipulation of Bioparticles

Manipulation of microscale bioparticles including living cells is of great significance to the broad bioengineering and biotechnology fields. Dielectrophoresis (DEP), which is defined as the interactions between dielectric particles and the electric field, is one of the most widely used techniques for the manipulation of bioparticles including cell separation, sorting, and trapping. Bioparticles experience a DEP force if they have a different polarization from the surrounding media in an electric field that is nonuniform in terms of the intensity and/or phase of the electric field. A comprehensive literature survey shows that the DEP-based microfluidic devices for manipulating bioparticles can be categorized according to the methods of creating the nonuniformity via patterned microchannels, electrodes, and media to generate the DEP force. These methods together with the theory of DEP force generation are described in this review, to provide a summary of the methods and materials that have been used to manipulate various bioparticles for various specific biological outcomes. Further developments of DEP-based technologies include identifying materials that better integrate with electrodes than current popular materials (silicone/glass) and improving the performance of DEP manipulation of bioparticles by combining it with other methods of handling bioparticles. Collectively, DEP-based microfluidic manipulation of bioparticles holds great potential for various biomedical applications.

Changes in Physical and Oral Function after a Long-Term Care Prevention Program in Community-Dwelling Japanese Older Adults: A 12-Month Follow-Up Study

Background: The aim of this prospective cohort study was to clarify changes in physical and oral function in older adults after completing a 3-month health program combining physical and oral exercise, oral health instruction, and nutritional guidance. Methods: Subjects were 34 women aged at least 70 years (mean age 79.2 years) in Bungotakada City, Oita Prefecture, Japan. Physical and oral function was investigated on the first day (baseline), at the end of the program, and 6 and 12 months after completing the health program. Physical function was measured using handgrip strength test, timed up and go (TUG) test and one-leg standing time test. Oral diadochokinesis test and repetitive saliva swallowing test (RSST) were employed to assess oral function. Results: TUG scores were significantly lower at 6 and 12 months than at baseline in participants aged ≥70 and <80 years. The repetition rate of the monosyllables /pa/, /ta/, and /ka/ was improved at the end of program in participants aged ≥70 and <80 years and increased to more than 6 times/second at 12 months. Conclusions: Our 3-month health program maintained improvements in oral and physical function in older women 1 year after completing the program.

Association of oral Epstein-Barr virus with periodontal health in Japanese adults

Previous studies have demonstrated that oral Epstein-Barr virus (EBV) is associated with periodontitis. However, the relationship between periodontitis and oral EBV has not been fully elucidated by reducing the effects of confounding factors. The aim of the present study was to clarify the association between oral Epstein-Barr virus (EBV) and oral health status among middle-aged and older Japanese individuals. A total of 124 patients (46 males and 78 females; mean age, 69.2 years; age range, 35-90 years) who visited Hiroshima University Hospital between October 2018 and December 2019 were recruited into the present study. EBV DNA positivity was determined in 124 oral rinse samples using quantitative PCR. Periodontal disease-related bacteria were also detected by PCR analysis. EBV DNA was determined as positive in 16 of the 124 enrolled patients (12.9%). No significant difference was identified between EBV DNA and clinical factors (sex, age, remaining teeth, denture use, smoking or medical history). Of the 38 patients with periodontal pockets ≥6 mm, 10 were EBV DNA positive (26.3%). There was a significant association between EBV DNA positivity and probing depth (P=0.01). Additionally, a significant association was identified between bleeding on probing (BOP) and EBV DNA positivity (P=0.03). To investigate the relationship between EBV and periodontal health status, propensity score-matching was determined between participants without ≥4 mm periodontal pockets and BOP (participants with good periodontal health) and those with ≥4 mm periodontal pockets, BOP or both (participants with poor periodontal health). A total of 35 matched pairs were identified among the patients. Patients with poor periodontal health exhibited a higher EBV DNA positivity rate (25.7%) than those with good periodontal health (0.0%). Additionally, there was a significant association between EBV DNA positivity and periodontal health status (P=0.001). T. denticola-positive participants exhibited a higher EBV DNA positivity rate than negative participants (17.6 vs. 9.6%). However, there was no significant difference. The results indicated that oral EBV may be markedly associated with periodontitis in middle-aged and older Japanese individuals.

Association of oral HPV16 infection with periodontal inflammation and the oral microbiome in older women

The present preliminary study aimed to investigate the association between oral human papillomavirus type 16 (HPV16) DNA prevalence and periodontal inflammation in older women. The association between oral HPV16 infection and oral health status has not been fully elucidated in older Japanese women. The present study investigated older women aged ≥60 years who visited Hiroshima University Hospital. The present study excluded subjects with clinical factors affecting HPV infection, such as current smoking, oral cancer and pre-malignant lesions, and immunodeficiency. Finally, 46 female patients (mean age, 74.6 years) were analyzed. Quantitative PCR analysis was performed to detect HPV16 DNA in oral rinse samples. A total of 4 participants (8.7%) were HPV16 DNA positive. There was a significant association between the HPV16 DNA positivity rate and bleeding on probing (P=0.03). Additionally, Prevotella intermedia positive cases exhibited a significantly higher HPV16 DNA positivity rate than negative cases (33.3 vs 3.8%). Furthermore, analysis of 16S ribosomal RNA in bacterial flora was performed to examine microbiome diversity in participants with ≥6 mm periodontal pockets and bleeding on probing. Importantly, the average percentage of Porphyromonas was significantly higher in HPV16 DNA positive cases compared with in HPV16 DNA negative cases (5.57 vs. 1.44%). By contrast, the average percentage of Veillonella was significantly lower in HPV16 DNA positive cases than in HPV16 DNA negative cases (2.43 vs. 8.51%). Prevotella was also lower in HPV16 DNA positive cases than in HPV16 DNA negative cases (4.0 vs. 8.23%). These results indicated that people with both deep periodontal pocket inflammation and oral HPV16 infection may not have Prevotella- or Veillonella-dominant oral microbiomes, and their microbiomes may exhibit their own distinctive characteristics. In conclusion, the results suggested that oral HPV16 infection may be associated with periodontal inflammation in older Japanese women. Further research is required to clarify the detailed association between oral HPV infection and the oral microbiome.

Professional oral care in end-of-life patients with advanced cancers in a hospice ward: improvement of oral conditions

Background

In end-of-life patients with advanced cancers, oral examination, oral care, and oral re-examination are crucial. Although oral symptoms are among the major complaints of end-of-life patients, few studies have focused on oral care in these patients. In this study, the association between oral symptoms and oral dryness among end-of-life patients was examined, and improvement of oral conditions after oral care interventions by a professional dentist was quantified.

Methods

This prospective intervention study included 27 terminally ill patients with advanced cancers in a hospice ward. Professional oral care was administered every morning, and the improvement of oral conditions was assessed by comparing oral conditions before and after the intervention. Oral assessment was performed using the Oral Health Assessment Tool (OHAT) and Oral Assessment Guide. Oral dryness was evaluated through Clinical Diagnosis Classification of oral dryness and an oral moisture device. Oral cleanliness was evaluated using a bacterial counter, and tongue smears were collected for Candida examination; furthermore, oral function was recorded.

Results

The presence of oral mucositis was closely associated with severe oral dryness (odds ratio [OR] = 14.93; 95% confidence interval [CI]: 1.95–114.38). The level of oral debris retention was significantly related to the degree of oral dryness (OR = 15.97; 95% CI: 2.06–123.72). The group with higher scores (OHAT > 8), which represent poor oral conditions, showed severe oral dryness (OR = 17.97; 95% CI: 1.45–223.46). Total OHAT scores (median: 7 vs 2) and those of other subgroups (lip, tongue, gums and tissues, saliva, and oral cleanliness showed a significant decrease after the intervention. Furthermore, the occurrence of mucositis (47.1% vs 0%), candidiasis rate (68.8% vs 43.8%), oral dryness self-sensation (63.6% vs 9.1%), and severe oral debris (52.9% vs 11.8%) decreased significantly.

Conclusions

Proper oral care can improve oral health and hygiene, reduce the rate of mucositis, reduce the sensation of oral dryness, increase oral moisture, and reduce the chances of oral infections among end-of-life patients. Daily oral care is necessary and can alleviate oral discomfort, increase food intake, and increase the chances of communication between end-of-life patients and their families.

Supplementary Information

Supplementary information accompanies this paper at 10.1186/s12904-020-00684-0.

Improvement of oral hypofunction by a comprehensive oral and physical exercise programme including textured lunch gatherings

The deterioration of oral function to a state of oral hypofunction (OHF) is reportedly associated with malnutrition and frailty. Thus, we Investigated the association of OHF with physical characteristics and function and test the effects of a programme including comprehensive oral and physical exercises and textured lunch gatherings (COPE-TeL programme) on oral and physical function in older adults with OHF. Eighty-six community-dwelling older adults were randomly assigned into control (n = 43) or intervention (n = 43) groups. The participants were further divided into OHF and normal oral function (NOF) sub-groups based on initial oral examinations. The intervention group participated in the 12-week COPE-TeL programme, while the control group performed the physical exercise regimen only. The differences in measured variables for physical and oral function between the OHF and NOF groups were statistically tested, and changes in the proportion of participants with OHF were examined. Physical function, such as hand grip strength and walking speed, was significantly lower in the OHF group at the initial assessment. The proportion of participants with OHF was 56% in the intervention group and 67% in the control group before the trial, which became significantly reduced after completing the COPE-TeL programme in the intervention group (26%, P = .002), but not in the controls (61%, P = .549). Older adults with OHF may have diminished physical function. The COPE-TeL programme of oral and physical exercises along with textured lunch gatherings may be effective for older adults with OHF.

Relationship between Oral Health Status and Postoperative Fever among Patients with Lung Cancer Treated by Surgery: A Retrospective Cohort Study

A retrospective observational study using an oral bacteria counter was conducted to evaluate the trends in the number of oral bacteria in the perioperative period of lung cancer patients and to verify the relationship between oral health status and postoperative fever. All patients received perioperative oral management (POM) by oral specialists between April 2012 and December 2018 at Kagawa Prefectural Central Hospital, Kagawa, Japan prior to lung cancer surgery. Bacteria counts from the dorsum of the tongue were measured on the day of pre-hospitalization, pre-operation, and post-operation, and background data were also collected retrospectively. In total, 441 consecutive patients were enrolled in the study. Bonferroni’s multiple comparison test showed significantly higher oral bacteria counts at pre-hospitalization compared to pre- and post-operation (p < 0.001). Logistic regression analysis showed that body mass index, performance status, number of housemates, number of teeth, and white blood cell count at pre-operation were significantly associated with postoperative fever. The study showed that POM can reduce the level of oral bacterial counts, that the risk of postoperative complications is lower with dentulous patients, and that appropriate POM is essential for prevent of complications. Therefore, POM may play an important role in perioperative management of lung cancer patients.

Reducing bacterial counts around the abutment following professional mechanical plaque removal at the implant bridge: A randomized crossover comparison of removing or not removing the superstructure

PURPOSE

The purpose of this study was to determine whether removing the superstructure of the implant bridge in cases of full-arch implant restorations for edentulous atrophic arches at the abutment level during professional mechanical plaque removal (PMPR) affects bacterial counts.

METHODS

This crossover clinical trial included 20 patients who received screw-retained prostheses at the abutment level. Patients were randomly assigned to two groups and received PMPR with or without removal of the superstructure. After a three-month washout period, the type of treatment was reversed between the groups. Bacterial counts around the cylinder and abutment were measured and compared before and after PMPR.

RESULTS

Bacterial numbers around the cylinder and abutment were significantly reduced after PMPR as compared with before PMPR regardless of whether the superstructure was removed (p <0.05). However the ratio of subjects with bacteria at 1.0 × 105 colony forming unit/ml (cfu/ml) or more after PMPR was significantly higher when the superstructure was not removed (p < 0.05). Among patients with bacterial counts of less than 10 × 105 cfu/ml, bacterial loads were reduced to less than 1.0 × 105 cfu/ml even when superstructures were not removed. Among patients with bacterial load of >10 × 105 cfu/ml, bacterial numbers were not reduced to <1.0 × 105 cfu/ml when PMPR was performed without removing the superstructure.

CONCLUSIONS

Removal of the superstructure in cases of full-arch implant restorations for edentulous atrophic arches during PMPR reduces bacterial numbers around the implant bridge at the abutment level.

Textural Changes by Mastication and Proper Food Texture for Patients with Oropharyngeal Dysphagia

Bolus texture is a key factor for safe swallowing in patients with dysphagia since an improper texture may result in aspiration and/or pharyngeal residue. This article discusses swallowing bolus texture from two key aspects: the textural change of solid food by mastication and the current standardized definition of food texture in Japan. When swallowing a liquid bolus, the texture is mostly maintained from ingestion to swallow onset. For solid food, however, the food is crushed by chewing and mixed with saliva before swallowing; the texture of the ingested food is modified to an easily swallowable form at swallow onset by mastication. Understanding the mechanism of mastication and its assessment are therefore important in deciding the proper diet for dysphagic patients. As standardized criteria for classifying the texture of food and liquid are essential as well, this report also describes the Japanese Dysphagia Diet 2013 that is commonly used as the standardized index for dysphagic diets in Japan.

Effects of Topical Hangeshashinto (TJ-14) on Chemotherapy-Induced Oral Mucositis

Purpose

Hangeshashinto (TJ-14), a Kampo medicine comprising seven types of herbs, has been used in Japan to alleviate the side effects associated with anticancer drug treatments. However, the pharmacological effects of this medicine currently remain unclear. The present study aimed to demonstrate the efficacy of TJ-14 against anticancer drug-induced stomatitis, the pain associated with which may have a negative impact on mastication and swallowing.

Methods

Mucositis was induced in Sprague-Dawley rats by cancer chemotherapy. Changes in body weight, stomatitis grades, histopathological scores, and oral bacterial counts were examined among TJ-14-treated, saline-treated, and Control (no treatment) rats. In vitro studies, including cell proliferation and wound healing assays, using epidermal keratinocyte and fibroblast cell lines were conducted.

Results

The local application of TJ-14 exerted strong antibacterial effects and attenuated oral chemotherapy-induced stomatitis in rats. TJ-14 also increased the viability and invasion of epidermal keratinocytes and fibroblasts.

Conclusion

The present results demonstrated the potential of TJ-14 to attenuate chemotherapy-induced stomatitis.

Improvement of physical and oral function in community-dwelling older people after a 3-month long-term care prevention program including physical exercise, oral health instruction, and nutritional guidance

Objective

There is limited evidence about the most appropriate way to improve physical and oral function in older people. The aim of this study was to clarify the effectiveness of a long-term care prevention program combining physical exercise, oral health instruction, and nutritional guidance among community-dwelling older people.

Materials and methods

We included 43 older people aged at least 65 years (seven men and 23 women; mean age 75.3 years) in Bungotakada City, Japan. The 3-month program involved a weekly intervention. Physical and oral function was investigated on the first day of the program (i.e., baseline) and at the end of the program (i.e., after 3 months). Physical function was examined using measures such as handgrip strength, timed up-and-go test, and one-leg standing time with eyes open. An oral diadochokinesis test was used to assess oral function.

Results

Mean maximum handgrip strength increased significantly in older people aged ≤74 years (younger participants) and those aged ≥75 years (older participants) after 3 months compared with the baseline. The timed up-and-go test duration was significantly lower in older participants after the program. Repetition of the monosyllables pa and ka and the repetitive saliva swallowing test was significantly improved in both groups. The dysphagia risk assessment for the community-dwelling elderly score was significantly lower in younger participants after 3 months.

Conclusion

Participation in a 3-month program combining physical exercise, oral health instruction, and nutritional guidance may contribute to improvement or maintenance of oral and physical function in older people.

Effects of ozone nano-bubble water on mucositis induced by cancer chemotherapy

No effective, reliable treatment for stomatitis associated with cancer therapy has been established. This study focused on the its effectiveness of ozone nano-bubble water (ONBW) for the treatment of chemotherapy-induced stomatitis. Oral mucositis was induced in 14-week-old male Sprague-Dawley rats (N = 21). The animals were randomly divided into 3 groups: 7 without treatment (control); 7 treated with physiological salt solution (saline); and 7 treated with ONBW. Animals were weighed on Days 7, 9, 11, and 16. Stomatitis grade evaluation and bacterial count measurements were performed before rinsing in all animals 3, 5, and 10 days after acetic acid irritation (Days 9, 11, and 17 respectively). Weight loss after stomatitis creation was observed in all groups, with significant differences between the control and ONBW groups and between the saline and ONBW groups on Day 16. The stomatitis grade did not worsen during the experimental period in any group, with the lowest grades in the ONBW group on Days 11 and 16. Significant differences were identified between the control and ONBW groups and between the saline and ONBW groups on Days 11 and 16. Oral bacterial counts tended to decrease over time in all three groups, with the greatest decrease in the ONBW group, followed by the saline group. The decrease in the bacterial count was steepest in the ONBW group. Rinsing out the oral cavity with ONBW decreased bacterial counts and encouraged the healing of oral chemotherapy-induced stomatitis. ONBW may be an effective treatment for chemotherapy-induced stomatitis.

Risk indicators of dental caries and gingivitis among 10-11-year-old students in Yangon, Myanmar

OBJECTIVES

To obtain basic data on dental caries and gingival status of students in Myanmar, and to identify related risk indicators, including socioeconomic conditions and oral health behaviours and habits.

STUDY DESIGN

This cross-sectional study enrolled 537 fifth-grade students in Myanmar. Oral health behaviours and dietary patterns of students were assessed using questionnaires. Oral examinations were conducted to identify dental caries and gingivitis, and the oral samples were obtained to determine the bacteria levels in dental plaque.

RESULTS

The dental caries prevalence was 68.5%, with a mean number of decayed teeth of 2.07 ± 2.15. The prevalence of gingivitis was 98.9%, and the mean number of inflamed gingival areas in the anterior region was 16.2 ± 5.4. No significant differences were found between the sexes in terms of dental caries and gingivitis. Oral hygiene was significantly poorer, and levels of bacteria in dental plaque were significantly higher in boys than in girls. Multiple linear regression tests were used to analyse the association between risk indicators and dental caries and gingivitis. Tooth brushing frequency, a daily habit of mouth rinsing, dental visit experience, consumption of sugary snacks and oral hygiene status were significantly associated with dental caries. Mother's occupation, tooth brushing frequency, consumption of sweet drinks, oral hygiene status and bacterial levels in dental plaque were significant predictors of gingivitis.

CONCLUSIONS

Myanmar students had a high prevalence of dental caries and gingivitis. Socioeconomic condition, oral hygiene status and oral health behaviours were all determined to be significant risk indicators.

Measurement of the real part of the Clausius-Mossotti factor of dielectrophoresis for Brownian particles

A method is proposed for measuring the real part of the Clausius-Mossotti factor ( K r ) of dielectrophoresis for Brownian particles based on a solution of the Smoluchowski equation using a designed polydimethysilloxane microchannel with planar hyperbolic electrodes on its glass substrate. An approximate two-dimensional spring-like dielectrophoretic force is generated in the device, and the data necessarily measured is the time evolution of the in-plane particle displacement undergoing confined Brownian motion. Validity of the measurement was checked against the zeta potentials in the literature based on the classical theory of surface conductance using polystyrene particles of size of one micron. As the dielectrophoretic force depends on K r , which is usually unknown for bio-particles and some engineered particles, and is seldom measured; this study is important from the academic point of view and could be helpful for the manipulation and characterization of sub-micron particles using dielectrophoresis. Extension of the method to the measurement of permanent dipole moment and total polarizability of particle was developed theoretically and discussed by incorporating an optical tweezer into the present device.

Pilot study for risk assessment of aspiration pneumonia based on oral bacteria levels and serum biomarkers

Background

Aspiration pneumonia is a serious problem among elderly patients; it is caused by many risk factors including dysphagia, poor oral hygiene, malnutrition, and sedative medications. The aim of this study was to define a convenient procedure to objectively evaluate the risk of aspiration pneumonia in the clinical setting.

Methods

This prospective study included an aspiration pneumonia (AP) group, a community-acquired pneumonia (CAP) group, and a control (Con) group (patients hospitalized for lung cancer chemotherapy). We used the Oral Health Assessment Tool (OHAT), which assesses oral hygiene, and evaluated performance status, body mass index, serum albumin levels, substance P values in plasma, and oral bacterial counts.

Results

The oral health as assessed by the OHAT of the aspiration pneumonia group was significantly impaired compared with that of the CAP group and the control (5.13 ± 0.18, 4.40 ± 0.26, 3.90 ± 0.22, respectively; p < 0.05). The oral bacterial count in the aspiration pneumonia group (7.20 ± 0.11) was significantly higher than that in the CAP group (6.89 ± 0.12), consistent with the OHAT scores. Oral bacterial count was significantly reduced by oral care.

Conclusions

OHAT and oral bacterial counts can be a tool to assess the requirement of taking oral care and other preventive procedures in patients at high risk of aspiration pneumonia.

Comparison between Two Assessment Tests for Oral Hygiene: Adenosine Triphosphate + Adenosine Monophosphate Swab Test and Bacteria Number Counting by Dielectrophoretic Impedance Measurement

Objective assessments of oral hygiene are important to prevent oral and systemic diseases. Two objective assessment tests are available to assess oral hygiene; (1) the adenosine triphosphate (ATP) + adenosine monophosphate (AMP) swab test, which incorporates a luciferase assay and (2) a bacteria count using the dielectrophoretic impedance measurement (DEPIM) method. In this study, we compared the two tests using a subjective visual assessment by professional clinicians and investigated the clinical significance of these tests. Twenty-seven young participants (mean age 26.3 ± 3.2 years) and twenty-seven older participants (mean age 75.1 ± 5.9 years) were recruited. Oral bacteria were sampled from three areas, including the tongue dorsum, the buccal mucosa, and the faucal mucosa, and saliva was obtained using a cotton swab. The amount of ATP + AMP and the number of bacteria were measured by each specific apparatus. Additionally, one examiner assessed the overall condition of oral hygiene using the visual analog scale (VAS). In the ATP + AMP swab test, the means were highest in saliva. For the bacteria count, the means were higher in the tongue dorsum and saliva and lower in the faucal and buccal mucosa. The results of the subjective assessment of oral hygiene indicated that the VAS-value was 3.78 ± 0.97 for the young group and 3.35 ± 0.81 for the older group. No significant difference was observed between the two groups. Additionally, no significant relationship between the values of the ATP + AMP swab test and the bacteria count was found for any of the four sample sites. In the older group, the subjective assessment of oral hygiene was significantly correlated with the values of the ATP + AMP swab test (multiple correlation coefficient = 0.723, p = 0.002). In conclusion, the values provided by the ATP + AMP swab test were not always correlated to the bacteria count. The results of this study suggest that the subjective assessment of oral hygiene was more highly correlated with the results of the ATP + AMP swab test, as compared to the bacterial count assay.

Relationship between oral environment and frailty among older adults dwelling in a rural Japanese community: a cross-sectional observational study

Background

Oral functions are known to decline with aging. However, there is limited evidence that supports the relationship between oral health and frailty. This study aimed to clarify the relationship between oral hygiene conditions, measured by remaining teeth and mucosa, and frailty among elderly people dwelling in a Japanese rural community.

Methods

We surveyed self-reliant elderly individuals aged ≥65 years who were dwelling in the Sasayama-Tamba area of Hyogo, Japan. Frailty was evaluated according to the total score of the Kihon Checklist (KCL). Based on the KCL score, elderly participants were divided into three groups: robust, pre-frail, and frail. The items measured to evaluate oral environment included the number of remaining teeth, denture usage condition, oral hygiene status, dry mouth condition, and salivary bacterial count. For statistical analysis, Fisher’s exact test, one-way analysis of variance, and multiple comparison technique were used.

Results

Of 308 elderly participants, 203 (65.9%), 85 (27.6%), and 20 (6.5%) belonged to the robust, pre-frail, and frail groups, respectively. The proportion of participants who were judged to have poor hygiene was significantly higher in the frail group than in the other two groups. The bacterial count was significantly smaller in the frail group than in the robust group, and the frail group had fewer number of remaining teeth than the other two groups, suggesting that the number of remaining teeth may be associated with bacterial count.

Conclusion

In elderly adults, physical frailty may affect the oral hygiene status and condition of the remaining teeth.

Detection of oral bacteria on the tongue dorsum using PCR amplification of 16S ribosomal RNA and its association with systemic disease in middle-aged and elderly patients

The association between oral health and systemic disease is recognized in the literature. The present study aimed to clarify the association between oral bacteria on the tongue dorsum and factors associated with oral health and systemic disease in middle-aged and elderly patients. The association between bacterial numbers, oral health status and systemic disease was preliminarily investigated in 70 patients (mean age, 69.5 years; range, 45-92 years) who visited the Department of Oral Health, Hiroshima University Hospital (Hiroshima, Japan). The bacterial 16S ribosomal RNA gene was employed to quantitate bacterial numbers using real-time polymerase chain reaction (PCR). PCR was also performed to detect the DNA of periodontal disease-related bacteria. Oral bacterial numbers were marginally negatively correlated with moisture levels on the tongue surface [Spearman's rank correlation coefficient (R)=-0.131, P=0.28). Subjects with bleeding on probing (BOP) or a ≥4 mm probing depth (PD) exhibited higher Porphyromonas gingivalis (P. gingivalis)-positive rates (50.0 and 51.1%, respectively) than those without BOP or a <4 mm PD (39.5 and 30.4%, respectively). Subjects with medical histories of hypertension, diabetes, stroke and heart disease exhibited a trend toward higher P. gingivalis-positive rates than those without such disorders. These findings indicated that the tongue moisture level may be associated with bacterial numbers on the tongue surface, while P. gingivalis on the tongue surface may be associated with systemic and periodontal diseases. Further investigation in a larger number of participants is necessary to clarify the correlation between bacterial numbers and systemic disease.

Comparison of wiping and rinsing techniques after oral care procedures in critically ill patients during endotracheal intubation and after extubation: A prospective cross-over trial

AIM

Endotracheal intubation of critically ill patients increases the risk of aspiration pneumonia, which can be reduced by regular oral care. However, the rinsing of the residual oral contaminants after mechanical cleaning carries the risk of aspirating the residue during the intubation period. Removing the contaminants by wiping with mouth wipes could be an alternative to rinsing with water because of no additional fluid. This study tested: (i) the amount of oral bacteria during endotracheal intubation and after extubation; and (ii) the changes in the bacterial count during oral care procedures.

METHODS

Thirty-five mechanically ventilated patients in the intensive care unit were enrolled. The amount of bacteria on the dorsal tongue surface was counted before and following oral care and then after the elimination of contaminants either by rinsing with water and suctioning or by wiping with mouth wipes. The oral bacterial amount was compared statistically between the intubation and extubation status and among set time points during the oral care procedure.

RESULTS

The oral bacterial count was significantly decreased after extubation. During the oral care procedure, the oral bacterial amount was significantly lower after eliminating the contaminants either by rinsing or wiping, with no remarkable difference between the elimination techniques.

CONCLUSIONS

The findings suggest that the oral bacterial amount is elevated during endotracheal intubation, which could increase the risk of aspiration pneumonia. The significant reduction in the bacterial count by wiping indicates that it might be a suitable alternative to rinsing for mechanically ventilated patients.

Synergistic and additive interactions of Serratia marcescens S-JS1 to the chemical insecticides for controlling Nilaparvata lugens (Hemiptera: Delphacidae)

The combined use of entomopathogens and chemical agents has been suggested as an alternative strategy to control pest insects. However, the effectiveness of combinations of entomopathogenic bacteria and insecticides against rice planthoppers is largely unknown. Here, we evaluated the separate and combined effects of an entomopathogenic bacterium, Serratia marcescens S-JS1, and spirotetramat or thiamethoxam insecticides against third-instar nymphs of Nilaparvata lugens Stål (Hemiptera: Delphacidae) under laboratory and greenhouse conditions. Under laboratory conditions, the combinations caused higher mortality in the third-instar nymphs of N. lugens and produced a synergistic or additive effect compared with the treatments with either bacterial suspension or insecticide alone. Application of S-JS1 (1 × 109 cfu/ml) in combination with 20 mg/liter spirotetramat resulted in 80.5% of N. lugens nymphal mortality, compared with 52.7% in spirotetramat alone treatments, and interactions resulted in a synergistic responses. Other combination treatments of S-JS1 with either insecticide concentration all exhibited additive interactions. In further greenhouse tests, S-JS1 (1 × 109 cfu/ml) + spirotetramat (20 mg/liter) and S-JS1 (1 × 109 cfu/ml) + thiamethoxam (5 mg/liter) showed additive effects against the nymphs, and were found to be most effective relative to their individual treatments on days 5 and 9. Our results indicate that S. marcescens S-JS1 combined with insecticide may provide a promising new strategy for controlling N. lugens.

High HPV16 E6 viral load in the oral cavity is associated with an increased number of bacteria: A preliminary study

In a previous study, the present research group reported that males had a significantly higher prevalence of human papillomavirus (HPV)16 than females in oral rinse samples. The objective of the present study was to examine the relationship between HPV16 viral load and clinical factors, including remaining teeth, denture use and numbers of oral bacteria. A total of 124 patients (48 males and 76 females; mean age, 61.6 years; age range, 20-97 years) who visited the Department of Oral and Maxillofacial Reconstructive Surgery of Hiroshima University Hospital (Hiroshima, Japan) between November 2016 and August 2017 were analyzed. None of the patients had evidence of oral cancer or pre-malignant lesions, including epithelial dysplasia and leukoplakia. Quantitative polymerase chain reaction (qPCR) analysis was employed to examine the number of HPV16 viral copies. Furthermore, the number of oral bacteria was determined using the dielectrophoretic impedance measurement method. HPV16 was below the limit of detection in qPCR findings for samples obtained from 30 of the 124 subjects, thus the association of HPV16 viral copy number with clinical parameters was examined in the remaining 94 patients. The average number of HPV16 E6 DNA copies was 1.65±3.47 copies/cell (range, 0.07-25.3 copies/cell) and was significantly higher in subjects with a high oral bacteria count [≥10^6.5 colony forming unit (CFU)/ml] than in those with a low count (<10^6.5 CFU/ml) (0.79±0.98 vs. 2.06±4.11 copies/cell; P=0.030). The present results indicated that HPV16 viral load may be related to an increased bacterial number in the oral cavity. Further investigations are required to clarify the correlation between oral HPV load and oral hygiene status.

Intraoral electric potential via oral bacterial power generation -A novel mechanism of biofilm formation

In the early stages of biofilm accumulation, the electric charge of the dental enamel and pellicle surfaces is known to be involved. We therefore investigated the relationship between oral hygiene and intraoral electric potential (IoP) in 45 male participants using a double-blind study. IoP, but not body surface electric potential, was loosely correlated with oral hygiene condition (Oral Hygiene Index; OHI). IoP was also loosely correlated with smartphone use; however, there was no significant correlation between smartphone use and OHI. IoP elevation might be caused by OHI elevation resulting from biofilm formation as an internal factor, with smartphone use as an external factor. This in vitro study revealed the generating capacity of Streptococcus mutans accompanied by biofilm accumulation using a microbial fuel cell. These results suggest that IoP elevation is caused by biofilm accumulation induced by power generation of oral bacteria, resulting in elevation of OHI.

Comparison of Sensitivity and Quantitation between Microbead Dielectrophoresis-Based DNA Detection and Real-Time PCR

In this study, we describe a microbead-based method using dielectrophoresis (DEP) for the fast detection of DNA amplified by polymerase chain reaction (PCR). This electrical method measures the change in impedance caused by DEP-trapped microbeads to which biotinylated target DNA molecules are chemically attached. Using this method, measurements can be obtained within 20 min. Currently, real-time PCR is among the most sensitive methods available for the detection of target DNA, and is often used in the diagnosis of infectious diseases. We therefore compared the quantitation and sensitivity achieved by our method to those achieved with real-time PCR. We found that the microbead DEP-based method exhibited the same detection limit as real-time PCR, although its quantitative detection range was slightly narrower at 10–10⁵ copies/reaction compared with 10–10⁷ copies/reaction for real-time PCR. Whereas real-time PCR requires expensive and complex instruments, as well as expertise in primer design and experimental principles, our novel method is simple to use, inexpensive, and rapid. This method could potentially detect viral and other DNAs efficiently in combination with conventional PCR.

Inhibitory effect for proliferation of oral bacteria in dogs by tooth brushing and application of toothpaste

To investigate inhibitory effect for oral bacterial proliferation, we divided 12 dogs into 3 groups; scaling alone (C; control group), brushing (B) and application of toothpaste (P). Before scaling (Pre) and at 0 to 8 weeks after scaling (0-8 w), we collected oral bacteria from the dental surface every week and counted them using a bacterial counter. The results demonstrated a significant reduction in the number of oral bacteria for group B relative to Pre and group C, as well as for group P relative to group C at 5-7 w. Consequently, brushing may inhibit an increase in the number of oral bacteria, and toothpaste may be effective at a certain level, although not more than that of brushing.

Multicentered epidemiological study of factors associated with total bacterial count in the saliva of older people requiring nursing care

AIM

To clarify whether the number of present teeth, independent of other well-known factors, was associated with the total bacterial count in the saliva of older people requiring care at nursing homes in a multicentered epidemiological survey.

METHOD

The participants were 618 older people (mean age 86.8 ± 6.9 years; 122 men, 496 women) residing in 14 nursing homes across Japan. The dependent variable was the participant's salivary bacterial count, and the independent variables were basic demographic data, oral conditions and activity of daily living (measured by Barthel Index). Statistical analysis was first carried out by Student's t-test, Pearson's correlation coefficient analysis and Spearman's rank correlation coefficient analysis. Independent variables found to have a significant relationship to their salivary bacterial count by the univariate analyses were further examined by stepwise multivariate analysis.

RESULTS

The independent variables shown by univariate analysis to have a significant positive relationship with higher salivary bacterial count were presence of food residue (P = 0.001), absence of mouth dryness (P = 0.001), need of oral care assistance (P = 0.001), inability to keep the mouth opened (P = 0.009), inability to gargle (P = 0.002), denture use (P = 0.004), higher number of present teeth (P = 0.006) and lower Barthel Index (P = 0.001). Subsequent multivariate analysis identified presence of food residue (P = 0.031), higher number of present teeth (P = 0.043) and lower Barthel Index (P = 0.001) as independent associated factors for higher salivary bacterial count.

CONCLUSIONS

The present study found that presence of food residue, higher number of present teeth and decreased activity of daily living were significantly related to higher bacterial count in the saliva of older people requiring care. Geriatr Gerontol Int 2017; 17: 219-225.

Tooth brushing inhibits oral bacteria in dogs

In this study, scaling, polishing and daily tooth brushing were performed in 20 beagle dogs, and the number of oral bacteria was determined using a bacterial counter. The dogs were randomized into the scaling (S), scaling + polishing (SP), scaling + tooth daily brushing (SB) and scaling + polishing + tooth daily brushing (SPB) groups. Samples were collected from the buccal surface of the maxillary fourth premolars of the dogs immediately after scaling and every week thereafter from weeks 1 to 8. Throughout the study, the number of bacteria was significantly lower in the SB and SPB groups compared with the S group. The findings suggest that daily tooth brushing inhibited oral bacterial growth in the dogs.

Point-of-care detection of Tannerella forsythia using an antigen-antibody assisted dielectrophoretic impedance measurement method

The importance of periodontal treatment planning based on diagnosis with clinical detection of periodontal pathogens has been well recognized. However, reliable detection and quantification methods that can be conveniently used at chair-side have yet to be developed. This study aimed to evaluate the clinical use of a novel apparatus which uses an antigen-antibody reaction assisted dielectrophoretic impedance measurement (AA-DEPIM) for the detection of a prominent periodontal pathogen, Tannerella forsythia. A total of 15 patients with a clinical diagnosis of chronic periodontitis, three periodontally healthy volunteers and two with gingivitis were subjected to clinical and microbiological examinations. Saliva samples were analyzed for the presence of T. forsythia using AA-DEPIM, PCR-Invader and real-time PCR methods. The measurement values for total bacteria and T. forsythia using the prototype AA-DEPIM apparatus were significantly greater in periodontitis group than those in healthy/gingivitis group. Using the AA-DEPIM apparatus with tentative cut-off values, T. forsythia was detected for 14 (12 with periodontitis and 2 either healthy or with gingivitis) out of 20 individuals. The measurement for the detection of T. forsythia by the AA-DEPIM method showed a significant positive correlation with the detection by PCR-Invader (r = 0.541, p = 0.01) and the real-time PCR method (r = 0.834, p = 0.01). When the PCR-Invader method was used as a reference, the sensitivity and specificity of the AA-DEPIM method were 76.5% and 100%, respectively. The results suggested that the AA-DEPIM method has potential to be used for clinically evaluating salivary presence of T. forsythia at chair-side.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (UMIN-CTR) UMIN000012181.

Antimicrobial photodynamic therapy suppresses dental plaque formation in healthy adults: a randomized controlled clinical trial

Background

Oral care is important for oral and systemic health, especially for elderly institutionalized individuals and compromised patients. However, conventional mechanical plaque control is often difficult for these patients because of the pain or the risk of aspiration. Although antimicrobial photodynamic therapy (aPDT), which is considered an alternative or adjunct to mechanical approaches, has potential application as a less stressful method of daily plaque control, no clinical application of this technique has been reported.

Methods

We investigated the inhibitory effect of a combination of toluidine blue O (TBO), and a red light-emitting diode (LED) on dental plaque formation in healthy volunteers. The optimal concentration of TBO was determined in preliminary in vitro experiments to evaluate the bactericidal effect of aPDT on Streptococcus oralis and to clarify its safety in fibroblast cells. To survey the mechanism of TBO-mediated aPDT, the quality and quantity of reactive oxygen species (ROS) generated during aPDT were also examined using electron spin resonance (ESR) spectroscopy. Subsequently, the inhibitory effect of aPDT on dental plaque formation was investigated in eleven subjects as a clinical pilot study. The right or left mandibular premolars were randomly assigned to the treatment (with aPDT) or control (without aPDT) groups. In total, aPDT was applied six times (twice per day) to the teeth in the test group over a period of four days. On the fourth day, the study concluded and the analyses were performed.

Results

A combination of 500 or 1000 μg/ml TBO and LED irradiation for 20 s significantly decreased the number of colony forming units of Streptococcus oralis. The cytotoxicity of aPDT was comparable to that of standard antiseptics used in the oral cavity. Hydroxyl radicals were detected by ESR analysis, but singlet oxygen was not. A randomized controlled trial demonstrated that aPDT with 1000 μg/ml TBO and red LED irradiation significantly suppressed dental plaque formation without harming teeth or the surrounding tissues.

Conclusions

aPDT has the potential to be a promising novel technical modality for dental plaque control.

Trial registration

This trial was registered with University Hospital Medical Information Network Clinical Trials Registry (number UMIN000012504).

Electronic supplementary material

The online version of this article (doi:10.1186/1472-6831-14-152) contains supplementary material, which is available to authorized users.

Evaluation of a rapid oral bacteria quantification system using dielectrophoresis and the impedance measurement

To clarify the availability of the dielectrophoretic impedance measurement (DEPIM) system as the evaluator for oral care, we evaluated the usefulness of DEPIM system by comparison with the standard plate counting (SPC) method. First, the relationship between the DEPIM results and bacterial concentration measured by SPC was clarified. Next, the measurement of the microorganism number in a mixed suspension was evaluated with DEPIM and SPC. The bacterial counts with DEPIM strongly correlated with those with SPC (r(2)=0.633-0.997) and this correlation was also shown in the measurement of a mixed bacterial suspension (ranging from 10(5) to 10(8) cfu/ml) of two bacterial species. Moreover, the experiments using dissociating enzymes to eliminate the influence of the size of the bacterial aggregates demonstrated that the microbial measurement results with DEPIM are unaffected by bacterial aggregates. This study demonstrated that bacterial counts with DEPIM strongly correlated with those with SPC and were unaffected by bacterial aggregates.

Relationship between oral bacteria count and pneumonia onset in elderly nursing home residents

AIM

Oral bacteria, which are a source of infection for aspiration pneumonia, were examined in frail older adults with the aim of establishing a standard bacteria count that indicates the risk of pneumonia onset in this group.

METHODS

A survey of bacteria count in the saliva using a simple instrument for measurement of the number of oral bacteria, along with factors including swallowing function and nutritional status, was carried out in 691 elderly individuals requiring care (137 men; mean age 82.6 ± 8.3 years; 554 women; mean age 88.0 ± 7.1 years; total mean age 86.7 ± 7.8 years) at 16 nursing homes in Japan. All participants gave their consent for inclusion in the present study. During a 6-month follow-up period, participants who developed pneumonia were identified, and relationships between the factors measured at the start of the period and pneumonia onset were examined.

RESULTS

During the 6-month follow-up period, 33 participants (4.8%; 5 men, 28 women; mean age 88.3 ± 7.4 years) developed pneumonia. Pneumonia onset was significantly associated with reduced activities of daily living, swallowing dysfunction and undernourishment. Logistic regression analysis identified a saliva bacteria count of 10(8.5)  colony-forming units/mL as an independent explanatory factor for pneumonia onset (P = 0.012, RR = 3.759).

CONCLUSIONS

Oral bacteria count of 10(8.5)  colony-forming units/mL saliva in an elderly person requiring care was identified as a risk factor for pneumonia onset.