Current status and factors of periodontal disease among Japanese high school students: a cross-sectional study

INTRODUCTION

This study aimed to investigate the prevalence of periodontal disease and the factors of the disease among high school students.

METHOD

The participants were all students aged 15-18 years (n = 1202) at a high school in Japan. The data on oral health perceptions and behaviours were collected by a questionnaire survey. The prevalence of periodontal disease among them was investigated with the partial community periodontal index (PCPI). A logistic regression analysis was used to identify the factors associated with the PCPI.

RESULTS

A total of 1069 students (88.9%) participated in this study. The prevalence of gingival bleeding, calculus, pocket depth of 4-5 mm, and pocket depth of 6 mm or more were 44.2%, 42.2%, 11.4%, and 1.6%, respectively. Approximately one-third of the students had a fear of dental treatment, and only 28.4% used dental floss. The results of logistic regression analysis, adjusted for sex and school year, showed that not visiting dentists regularly, not using dental floss, brushing teeth for less than 5 min, fear of dental treatment, and drinking sports drinks frequently were positively associated with periodontal conditions.

CONCLUSION

This study identified a high prevalence of periodontal disease among Japanese high school students aged 15-18 years and its risk factors, such as poor oral health behaviours and fear of dental treatment.

Application of Lactobaillus salivarius WB21 to the Oral Care of Healthy Older Adults: A Randomized, Double-Blind, Placebo-Controlled Crossover Comparative Study

Objective: A randomized, double-blind, placebo-controlled crossover comparative study was conducted in a healthy older population to assess the usefulness of Lactobacillus salivarius WB21 (WB21) ingestion for oral self-care. Methods: The study population included 33 healthy older individuals who were randomly divided into two groups (A and B). Group A consumed WB21 tablets during the first two months and placebo tablets during the following two months. Group B consumed placebo tablets during the first two months and WB21 tablets during the following two months. Before and after ingestion, oral examination, mouth odor test, and saliva collection were performed a total of four times. In addition, health conditions were obtained from a questionnaire survey at the study’s midpoint. Results: Two people in group A and one person in group B dropped out of the study. Thus, 15 people in group A and 15 people in group B were included in the analysis. Over two months of WB21 ingestion, salivary secretory IgA increased significantly (p = 0.047) and tongue coating score decreased significantly (p = 0.013). The plaque index, bleeding on probing, and mouth odor levels (H₂S and CH₃SH concentrations) did not change. During the 6-month study period, no caries, deterioration of periodontitis, or changes in oral health or systemic subjective symptoms were observed. Conclusion: Continuous ingestion of WB21-containing tablets may promote self-care of the teeth and mouths of healthy older adults. Trial registration: R000028335 (UMIN-CTR).

The effects of cigarette smoking on the salivary and tongue microbiome

Objectives

It has been suggested that smoking affects the oral microbiome, but its effects on sites other than the subgingival microbiome remain unclear. This study investigated the composition of the salivary and tongue bacterial communities of smokers and nonsmokers in periodontally healthy adults.

Methods

The study population included 50 healthy adults. The bacterial composition of resting saliva and the tongue coating was identified through barcoded pyrosequencing analysis of the 16S rRNA gene. The Brinkman index (BI) was used to calculate lifetime exposure to smoking. The richness and diversity of the microbiome were evaluated using the t‐test. Differences in the proportions of bacterial genera between smokers and nonsmokers were evaluated using the Mann–Whitney U test. The quantitative relationship between the proportions of genera and the BI was evaluated using Pearson's correlation analysis.

Results

The richness and diversity of the oral microbiome differed significantly between saliva and the tongue but not between smokers and nonsmokers. The saliva samples from smokers were enriched with the genera Treponema and Selenomonas. The tongue samples from smokers were enriched with the genera Dialister and Atopobium. The genus Cardiobacterium in saliva, and the genus Granulicatella on the tongue, were negatively correlated with BI values. On the other hand, the genera Treponema, Oribacterium, Dialister, Filifactor, Veillonella, and Selenomonas in saliva and Dialister, Bifidobacterium, Megasphaera, Mitsuokella, and Cryptobacterium on the tongue were positively correlated with BI values.

Conclusions

The saliva and tongue microbial profiles of smokers and nonsmokers differed in periodontally healthy adults. The genera associated with periodontitis and oral malodor accounted for high proportions in saliva and on the tongue of smokers without periodontitis and were positively correlated with lifetime exposure to smoking. The tongue might be a reservoir of pathogens associated with oral disease in smokers.

Novel oral biomarkers predicting oral malodor

OBJECTIVE

We sought new markers to predict oral malodor.

STUDY DESIGN

Seventy-five adults complaining of oral malodor were classified into 3 groups clinically: no oral malodor, physiologic oral malodor, and periodontitis-derived oral malodor. In addition to conventional clinical parameters, 7 salivary components, occlusal force, and lip-closing force were compared among the groups.

RESULTS

Concerning the salivary components, cariogenic bacteria, occult blood, leukocytes, and ammonia differed significantly among the groups. Multiple logistic regression analyses indicated that tongue-coating scores and ammonia levels were significantly associated with genuine oral malodor, including physiologic oral malodor and periodontitis-derived oral malodor, and the tongue-coating score, plaque index, and occult blood level were significantly associated with periodontitis-derived oral malodor. Occlusal force and lip-closing force did not differ among the groups. However, there was a statistically significant interaction between occlusal force and lip-closing force in oral malodor in women (P = .019).

CONCLUSIONS

Novel salivary markers, ammonia levels, and occult blood levels may predict genuine oral malodor and periodontitis-derived oral malodor, respectively. An interaction effect between occlusal force and lip-closing force on oral malodor was identified in women.

Effects of eradication of Helicobacter pylori on oral malodor and the oral environment: a single-center observational study

Objective

Although a relationship between Helicobacter pylori and oral malodor has been suggested, it remains to be confirmed. One reason for this is that many studies assess oral malodor subjectively. Another reason for the uncertainty is that the reduction in oral malodor may be due to the effect of antibiotics on the oral microbiota. In this study, changes in oral malodor along with the eradication treatment of H. pylori were investigated by organoleptic test and gas chromatography. In addition, the salivary bacterial composition and clinical parameters were analyzed.

Results

The organoleptic test score, hydrogen sulfide and dimethyl sulfide concentrations, and all clinical parameters except for tongue-coating score were significantly decreased at 1 week compared with baseline. Although antibiotic treatment also altered the overall composition of the salivary bacterial population, it had recovered at 7 weeks. On the date that H. pylori was determined to have been eradicated from all of the subjects (7 weeks after treatment), only the organoleptic test score was significantly lower compared with baseline. The hydrogen sulfide and dimethyl sulfide concentrations were non-significantly lower than those at baseline.

Development of an error-detection examination for conservative dentistry education

OBJECTIVE

For dental students, textbooks and lectures provide basic knowledge, and simulated and actual clinical training provide learning in technical and communication skills. At our college, conservative dentistry is taught in the third and fourth years of a 6-year undergraduate degree. Clinical training is undertaken subsequently in the fifth year and includes cavity preparation and composite resin filling tasks. However, despite the clinical importance of a full understanding surrounding these procedures, sixth-year students occasionally provide incorrect answers regarding these procedures in assessments. Although they demonstrated a basic understanding of the procedures, they may have forgotten the acquired knowledge during their clinical training. Therefore, we developed an error-detection examination to evaluate and improve fifth-year students' knowledge.

METHODS

Written detailed treatment procedures for standardized, typical, cases were presented to students. Some critical steps were intentionally written incorrectly, and students had to identify and correct these. After correcting the steps, students gave a presentation to their peers on their corrections. This was followed by a summary of the correct answers and a short lecture by the teacher. Students then completed a questionnaire investigating their experience of the examination.

RESULTS

Students misunderstood some key treatment steps, such as pretreatment of composite resin filling, amalgam removal, and ceramic inlay fitting. The questionnaire revealed that this method of testing applied knowledge was new to students and helped them to identify knowledge gaps. The test also increased their motivation to study conservative dentistry. Students were open to taking similar tests in different areas.

CONCLUSION

Although conservative dentistry is a basic field of dental treatment, mistakes in treatment can lead to early treatment failure or reduce the lifetime of a restored tooth. Therefore, students need to have a deep understanding of procedures. Error-detection examinations may help students identify knowledge gaps and provide useful feedback to teachers to identify areas that they should stress in earlier years.

Association between oral candidiasis and bacterial pneumonia: A retrospective study

OBJECTIVE

To investigate associated risk factors for oral candidiasis in elderly patients hospitalized in a community-based acute-care hospital with no dental units.

METHODS

Two hundred and twenty-eight elderly patients (male: 105, female: 123), who were hospitalized with several systemic diseases in a community-based acute-care hospital from May 2014 to October 2016, were retrospectively analysed by multiple logistic regression.

RESULTS

Multiple logistic regression analysis shows that bacterial pneumonia has a statistically strong relationship with oral candidiasis (p = 0.000, OR: 5.173, 95% CI: 2.368-11.298). The order followed is poor oral hygiene (p = 0.001, OR: 6.095, 95% CI: 2.003-18.545) and severe dry mouth (p = 0.043, OR: 2.507, 95% CI: 1.031-6.098). Other correlated factors including diabetes mellitus, denture wearer, dysphagia, malnutrition, requiring care and use of inhalation steroids, were not statistically significant in this study.

CONCLUSIONS

Bacterial pneumonia correlates with oral candidiasis.

BACTERIAL PNEUMONIA IS A POSSIBLE RISK FACTOR FOR ORAL CANDIDIASIS IN OLDER ADULTS: A RETROSPECTIVE COHORT STUDY

Both aspiration pneumonia and oral candidiasis are caused by opportunistic infection of intraoral commensals and have many similar risk factors linked to oral health in older adults. Candida albicans forms biofilms with respiratory bacteria such as Klebsiella pneumoniae and Pseudomonas aeruginosa. The aim of our study was to determine the relationship between bacterial pneumonia, including aspiration pneumonia, and oral candidiasis in older patients who were hospitalized with several systemic diseases in a community-based acute care hospital without a dental unit. We retrospectively analyzed 228 older patients (male: 105, female: 123) using multiple logistic regression. The mean age of the patients was 81.3 (SD: 11.1) years. Forty-four patients were oral candidiasis positive, and 78 patients suffered from bacterial pneumonia, including aspiration pneumonia. Results showed that bacterial pneumonia had the strongest statistical relationship with oral candidiasis (p=0.000, OR: 5.173, 95 % CI: 2.368–11.298). This was followed by poor oral hygiene (p=0.001, OR: 6.095, 95 % CI: 2.003–18.545) and severe dry mouth (p=0.043, OR: 2.507, 95 % CI: 1.031–6.098). Other conventional risk factors for oral candidiasis, such as diabetes mellitus, denture wearer, dysphagia, malnutrition, requiring care, use of inhalation steroids, were not statistically significant in this study. Fifteen species of bacteria, including Klebsiella pneumoniae and Pseudomonas aeruginosa, were detected by pharyngeal sputum culture in 24 of 31 patients who were diagnosed with both oral candidiasis and bacterial pneumonia. In conclusion, bacterial pneumonia is a possible new risk factor for oral candidiasis in older adults.

EFFECT ON MICROBIAL PRODUCTS ON CAESIUM ELUTION BEHAVIOUR FROM CLAY MINERALS

Some microorganisms in the environment make siderophores, which are low molecular chelators, to take up minerals from soil. Eleven bacteria were separated from the root of white clover by chlome azrol S (CAS) assay. Each bacterium was incubated in casamino acid (CAA) culture, and siderophores in CAA culture were purified. These extractions were applied to biotite or vermiculite spiked with Cs. From each clay mineral, 57.1-72.8% (5100 ppm), 55.6-63.8% (920 ppm) and 48.6-54.3% (2300 ppm), 31.6-34.4% (520 ppm) was eluted, respectively. To understand elution behaviour, Cs desorption ratio of each clay was measured every 30 min. The results indicate Cs elution was occurred quickly.

Induction and inhibition of oral malodor

Volatile sulfur compounds (VSCs) such as hydrogen sulfide (H₂ S) and methyl mercaptan (CH₃ SH) are the main components of oral malodor, and are produced as the end products of the proteolytic processes of oral microorganisms. The main pathway of proteolysis is the metabolism of sulfur-containing amino acids by gram-negative anaerobic bacteria. Gram-positive bacteria may promote VSC production by gram-negative anaerobes by cleaving sugar chains from glycoproteins and thus providing proteins. A large variety of bacteria within the oral microbiota are thought to be involved in the complex phenomenon of halitosis. Oral microbiota associated with a lack of oral malodor, oral microbiota associated with severe and H₂ S-dominant oral malodor, and oral microbiota associated with severe and CH₃ SH-dominant oral malodor have been distinguished through molecular approaches using the 16S rRNA gene. Pathological halitosis may primarily be addressed through treatment of causative diseases. In all cases, plaque control is the basis of oral malodor control, and dentifrices, mouthwashes, and functional foods play a supplementary role in addition to brushing. Recently, the use of natural ingredients in products tends to be favored due to the increase in antibiotic-resistant strains and the side effects of some chemical ingredients. In addition, probiotics and vaccines are expected to offer new strategies for improving the oral conditions through mechanisms other than antibacterial agents.

Computer-Assisted Three-Dimensional Corrective Osteotomy for Malunited Fractures of the Distal Radius Using Prefabricated Bone Graft Substitute

BACKGROUND

Three-dimensional computed tomography (3D-CT) imaging has enabled more accurate preoperative planning. The purpose of this study was to investigate the results of a novel, computer-assisted, 3D corrective osteotomy using prefabricated bone graft substitute to treat malunited fractures of the distal radius.

METHODS

We investigated 19 patients who underwent the computer-assisted 3D corrective osteotomy for a malunited fracture of the distal radius after the operation was stimulated with CT data. A prefabricated bone graft substitute corresponding to the patient's bone defect was implanted and internal fixation was performed using a plate and screws. We compared postoperative radiographic parameters of the patient's operated side with their sound side and analyzed clinical outcomes using Mayo wrist score.

RESULTS

All patients achieved bone union on X-ray imaging at final follow-up. The mean differences of palmar tilt, radial inclination and ulnar variance between the operation side and the sound side were 4.3°, 2.3° and 1.2 mm, respectively. The Mayo wrist score was fair in 4 patients and poor in 15 patients before surgery. At the final follow-up after surgery, the scores improved to excellent in 3 patients, good in 11 patients and fair in 5 patients. There were two patients with correction loss at the final follow-up, but no patient complained of hand joint pain.

CONCLUSIONS

We believe that computer-assisted 3D corrective osteotomy using prefabricated bone graft substitute achieved good results because it worked as a guide to the accurate angle.

Limited Wrist Arthrodesis for Scapholunate Advanced Collapse Wrist: Triangle Fixation for Four-Corner Fusion

BACKGROUND

Limited wrist arthrodesis with scaphoid excision is a useful treatment for scapholunate advanced collapse (SLAC) of the wrist. Multiple Kirschner wires were originally used for internal fixation of the four carpal bones, however long-term cast immobilization, pin tract infection, and hardware removal are still problematic. We introduce and evaluate the clinical outcomes of an internal fixation technique; triangle fixation for four-corner fusion, using three headless screws, as an alternative to conventional multiple Kirschner wires for the treatment of SLAC wrist.

METHODS

Five male patients with SLAC wrist secondary to three scaphoid nonunions and two scapholunate dissociations were treated with four-corner fusion using triangle fixation with three Double-threaded Japan screws. The mean age was 59.5 years (35-79 years) and the mean follow-up period was 40 months. After surgery, short arm splints were applied for 3-4 weeks, and then range of motion exercises were initiated.

RESULTS

Wrist range of motion and grip strength both improved postoperatively. At the final follow-up evaluation, bone union was completely achieved and satisfactory pain relief was observed in all patients.

CONCLUSIONS

Compared with the conventional Kirschner wire technique, the present technique shortens the period of splint immobilization due to a strong compression force in a skewed position, does not require pin removal or cause pin tract infections, and provides satisfactory results.

Lipopolysaccharide induces bacterial autophagy in epithelial keratinocytes of the gingival sulcus

BACKGROUND

Interactions of resident bacteria and/or their producing lipopolysaccharide (LPS) with sulcular epithelial keratinocytes may be regulated by autophagy in the gingival sulcus. In this study, we investigated an induction of bacterial autophagy in exfoliative sulcular keratinocytes of the gingival sulcus and cultured keratinocytes treated with Porphyromonas gingivalis-originated LPS (PgLPS).

RESULTS

Exfoliative sulcular keratinocytes showed an induction of autophagy, in addition to increased expression of LPS-mediated factors including lipopolysaccharide-binding protein and toll-like receptors (TLRs), leading to co-localization of bacteria with autophagosomes. In contrast, exfoliative keratinocytes from the free gingiva did not show similar autophagy. Autophagy activity in human cultured keratinocyte cells (HaCaT) was induced by PgLPS, which was dependent partially on the AMP-activated protein kinase (AMPK) pathway via increased intracellular reactive oxygen species (ROS) and was in association with an activation of TLR4 signaling. After incubation of cultured keratinocytes with E.coli BioParticles following PgLPS stimulation, co-localization of bioparticles with autophagosomes was enhanced. Conversely, blockage of autophagy with 3-methyladenin and LPS-binding with polymyxin B led to significant reduction of co-localization of particles with autophagosomes.

CONCLUSION

These findings indicate that PgLPS-induced autophagy is at least partially responsible for interaction between bacteria and sulcular keratinocytes in the gingival sulcus.

Two mechanisms of oral malodor inhibition by zinc ions

Objectives

The aim of this study was to reveal the mechanisms by which zinc ions inhibit oral malodor.

Material and Methods

The direct binding of zinc ions to gaseous hydrogen sulfide (H₂S) was assessed in comparison with other metal ions. Nine metal chlorides and six metal acetates were examined. To understand the strength of H₂S volatilization inhibition, the minimum concentration needed to inhibit H₂S volatilization was determined using serial dilution methods. Subsequently, the inhibitory activities of zinc ions on the growth of six oral bacterial strains related to volatile sulfur compound (VSC) production and three strains not related to VSC production were evaluated.

Results

Aqueous solutions of ZnCl₂, CdCl₂, CuCl₂, (CH₃COO)₂Zn, (CH₃COO)₂Cd, (CH₃COO)₂Cu, and CH₃COOAg inhibited H₂S volatilization almost entirely. The strengths of H₂S volatilization inhibition were in the order Ag+ > Cd₂+ > Cu₂+ > Zn₂+. The effect of zinc ions on the growth of oral bacteria was strain-dependent. Fusobacterium nucleatum ATCC 25586 was the most sensitive, as it was suppressed by medium containing 0.001% zinc ions.

Conclusions

Zinc ions have an inhibitory effect on oral malodor involving the two mechanisms of direct binding with gaseous H₂S and suppressing the growth of VSC-producing oral bacteria.

Three-dimensional assessment of the normal Japanese glenoid and comparison with the normal French glenoid

INTRODUCTION

In 2014, reverse total shoulder arthroplasty was approved in Japan. We were concerned that the base plate might be incompatible with Japanese who were generally smaller than Westerners. Therefore, we investigated the dimensions and morphology of the normal Japanese glenoid and compared with the normal French glenoid.

MATERIALS AND METHODS

One hundred Japanese shoulders without glenoid lesions (50 men and 50 women) were investigated and compared with 100 French shoulders (50 men and 50 women). Computed tomography was performed with 3-dimensional image reconstruction and images were analyzed using Glenosys software. Glenoid parameters (width, height, retroversion and inclination) were compared between Japanese and French subjects.

RESULTS

In Japanese subjects, the mean glenoid width was 25.5mm, height was 33.3mm, retroversion was 2.3° and inclination was 11.6° superiorly. In French subjects, the mean glenoid width was 26.7mm, height was 35.4mm, retroversion was 6.0° and inclination was 10.4° superiorly. Glenoid width and height were significantly smaller in Japanese subjects than French subjects (P=0.001 and P<0.001), while retroversion was significantly greater in French subjects (P<0.001). There was no significant difference of inclination.

CONCLUSIONS

These findings will help surgeons to identify suitable patients for RSA and perform the procedure with appropriate preoperative planning.

LEVEL OF EVIDENCE

IV: retrospective or historical series.

Dynamics of M1 macrophages in oral mucosal lesions during the development of acute graft-versus-host disease in rats

The role of macrophage infiltrates in oral mucosal acute graft-versus-host disease (AGVHD) remains unclear, although clinical studies suggest that macrophage infiltration correlates directly with the severity of AGVHD. In this study, we investigated the role of M1 macrophage infiltration in the oral mucosa of rats with AGVHD. Lewis rat spleen cells were injected into (Lewis × Brown Norway) F₁ rats to induce systemic GVHD. Tongue samples were evaluated using histology, immunohistochemistry, dual immunofluorescence, real-time reverse transcription-polymerase chain reaction, Transwell migration assays and Stamper-Woodruff binding assays. At the onset of oral mucosal AGVHD, dual immunofluorescence and migration assays revealed that M1 macrophages had accumulated in the basement membrane (BM) region via the laminin/CD29 β1 integrin pathway. Macrophage-secreted matrix metalloproteinase-2 was related to BM degradation. The adhesion of macrophages to the oral epithelium could be inhibited by pretreating macrophages with a CC chemokine receptor 2 (CCR2) antibody and/or pretreating lesion sections with monocyte chemoattractant protein-1 (MCP-1) antibody. Our data show that the migration and adhesion of M1 macrophages are associated with oral mucosal AGVHD, which is mediated in part by both laminin/CD29 β 1 intern and MCP-1/CCR2 pathways. Therefore, our study provides additional support for the contribution of macrophage infiltrate to the development of oral mucosal AGVHD.

Orbital Fat Volumetry and Water Fraction Measurements Using T2-Weighted FSE-IDEAL Imaging in Patients with Thyroid-Associated Orbitopathy

BACKGROUND AND PURPOSE

The quantitative evaluation of orbital fat proliferation and edema and the assessment of extraocular muscles are useful for diagnosing and monitoring thyroid-associated orbitopathy. To evaluate therapy-induced quantitative changes in the orbital fat of patients with thyroid-associated orbitopathy, we performed volumetric and water fraction measurements by using T2-weighted FSE iterative decomposition of water and fat with echo asymmetry and least-squares estimation (FSE-IDEAL) imaging.

MATERIALS AND METHODS

Orbital FSE-IDEAL images of 30 volunteers were acquired twice within 1 week. Nine patients with thyroid-associated orbitopathy underwent FSE-IDEAL imaging before and after methylprednisolone pulse therapy, and the treatment results were assessed by using their pre- and post-methylprednisolone pulse therapy clinical activity scores. We performed volumetric and water fraction measurements of orbital fat by using FSE-IDEAL imaging and evaluated interscan differences in the volunteers. In patients with thyroid-associated orbitopathy, we compared pre- and posttherapy orbital fat measurements and assessed the correlation between the pretherapy values and clinical activity score improvement.

RESULTS

The reproducibility of results obtained by the quantitative evaluation of orbital fat in volunteers was acceptable. After methylprednisolone pulse therapy, the water fraction in the orbital fat of patients with thyroid-associated orbitopathy was significantly decreased (P < .001). There was a significant positive correlation between the pretherapy water fraction and clinical activity score improvement (right, r = 0.82; left, r = 0.79) and a significant negative correlation between the pretherapy volume and clinical activity score improvement (bilateral, r = -0.84).

CONCLUSIONS

Volumetric and water fraction measurements of orbital fat by using FSE-IDEAL imaging are feasible and useful for monitoring the effects of therapy and for predicting the response of patients with thyroid-associated orbitopathy to methylprednisolone pulse therapy.

Resting salivary flow independently associated with oral malodor

Background

Dryness of the oral cavity is considered one cause of oral malodor. However, it is unclear which of the factors regulating the wetness of the oral cavity are involved in oral malodor development. This study investigated the effects of salivary flow and oral mucosal moisture on oral malodor.

Methods

The study population comprised 119 patients (48 men and 71 women, mean age of 50.6 ± 15.4 years) with complaint of oral malodor. After the oral malodor level had been evaluated by the organoleptic test and gas chromatography, the rates of stimulated saliva and resting saliva and the moisture levels of the tongue and buccal mucosa were measured. The plaque index, bleeding on pocket probing, probing pocket depth, and tongue coating score were also assessed. Strong oral malodor was defined as an organoleptic test score of ≥3.

Results

The flow rate of resting saliva in women was significantly lower than in men. The flow rate of resting saliva and the moisture levels of the tongue and buccal mucosa showed significant negative correlations with age. The flow rate of resting saliva was significantly lower in patients with strong oral malodor than in those with no or weak oral malodor. The flow rate of stimulated saliva and the moisture levels of the tongue and buccal mucosa had no relationship with strong oral malodor. Logistic regression analysis showed that a ≥5-mm probing pocket depth with bleeding on pocket probing, an increased tongue coating score, and decreased resting salivary flow were strong explanatory factors in clinical findings for oral malodor.

Conclusion

This study suggests that the flow rate of resting saliva is a significant modulating factor for oral malodor.

Electronic supplementary material

The online version of this article (doi:10.1186/s12903-016-0255-3) contains supplementary material, which is available to authorized users.

Applying orthodontic tooth extrusion in a patient treated with bisphosphonate and irradiation: a case report

Bisphosphonates and irradiation are useful medical treatments, but can often cause oral complications such as medication-related oral necrosis of the jaw (MRONJ) and osteoradionecrosis (ORN) during oral surgery, including tooth extraction. Therefore, we should take all risks into consideration carefully before choosing dental treatment for patients with a medical history of such therapies. A 55-year-old woman who underwent cord blood transplantation to treat extranodal natural killer T (NK/T) cell lymphoma (nasal type IVB) had a medical history of bisphosphonate and irradiation treatments. We treated her residual tooth root by applying orthodontic extrusion to avoid extraction and successfully restored the tooth. Application of an orthodontic tooth extrusion technique for conservative treatment of a residual tooth is a useful means of avoiding MRONJ or ORN in patients who have a medical history of bisphosphonate and irradiation treatments.

Relationship between salivary stress biomarker levels and cigarette smoking in healthy young adults: an exploratory analysis

Background

This study investigated the relationships among salivary stress biomarkers, cigarette smoking, and mood states.

Methods

The study population comprised 49 healthy sixth-year dental students at Fukuoka Dental College (39 men, 10 women; age, 23–31 years). Lifetime exposure to smoking was calculated using the Brinkman index (BI). Resting saliva samples were collected, and concentrations of cortisol, secretory immunoglobulin A (SIgA), interleukin (IL)-1β, interleukin-6, and tumor necrosis factor (TNF)-α were determined. Mood states (tension-anxiety, depression-dejection, anger-hostility, fatigue, confusion, and vigor) over the previous week were assessed using the Profile of Mood States - Brief Japanese Version.

Results

Salivary IL-1β levels were significantly higher in smokers than non-smokers (P = 0.044), regardless of the BI or mood state. A significant positive correlation was evident between the TNF-α level and the BI (P = 0.036), and the SIgA level was positively correlated with the BI (P = 0.067) but did not reach statistical significance. In terms of mood states, higher fatigue scores and lower vigor scores were observed in smokers. The TNF-α level and vigor score were negatively correlated (r = –0.229, P = 0.135), but the correlation did not reach statistical significance. However, the SIgA level and fatigue score were significantly positively correlated (r = 0.410, P = 0.005).

Conclusions

The TNF-α and SIgA levels were both positively correlated with the BI. Furthermore, the TNF-α level was negatively correlated with the vigor score, whereas the SIgA level was positively correlated with the fatigue score. Thus, salivary levels of TNF-α and SIgA may be used as biomarkers of mood states in healthy young smokers.

Surface vacuolar ATPase in ameloblastoma contributes to tumor invasion of the jaw bone

Ameloblastoma is the most common benign odontogenic tumor in Japan. It is believed that it expands in the jaw bone through peritumoral activation of osteoclasts by receptor activator of nuclear factor kappa-B ligand (RANKL) released from the ameloblastoma, as in bone metastases of cancer cells. However, the clinical features of ameloblastoma, including its growth rate and patterns of invasion, are quite different from those of bone metastasis of cancer cells, suggesting that different underlying mechanisms are involved. Therefore, in the present study, we examined the possible mechanisms underlying the invasive expansion of ameloblastoma in the jaw bone. Expression levels of RANKL assessed by western blotting were markedly lower in ameloblastoma (AM-1) cells than in highly metastatic oral squamous cell carcinoma (HSC-3) cells. Experiments coculturing mouse macrophages (RAW264.7) with AM-1 demonstrated low osteoclastogenic activity, as assessed by tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cell formation, probably because of low release of RANKL, whereas cocultures of RAW264.7 with HSC-3 cells exhibited very high osteoclastogenic activity. Thus, RANKL release from AM-1 appeared to be too low to generate osteoclasts. However, AM-1 cultured directly on calcium phosphate-coated plates formed resorption pits, and this was inhibited by application of bafilomycin A1. Furthermore, vacuolar-type H+-ATPase (V-ATPase) and H+/Cl- exchange transporter 7 (CLC-7) were detected on the surface of AM-1 cells by plasma membrane biotinylation and immunofluorescence analysis. Immunohistochemical analysis of clinical samples of ameloblastoma also showed plasma membrane-localized V-ATPase and CLC-7 in the epithelium of plexiform, follicular and basal cell types. The demineralization activity of AM-1 was only 1.7% of osteoclasts demineralization activity, and the growth rate was 20% of human normal skin keratinocytes and HSC-3 cells. These results suggest that the slow expansion of several typical types of ameloblastomas in jaw bone is attributable to its slow growth and low demineralization ability.

Brain imaging for oxidative stress and mitochondrial dysfunction in neurodegenerative diseases

Oxidative stress, one of the most probable molecular mechanisms for neuronal impairment, is reported to occur in the affected brain regions of various neurodegenerative diseases. Recently, many studies showed evidence of a link between oxidative stress or mitochondrial damage and neuronal degeneration. Basic in vitro experiments and postmortem studies demonstrated that biomarkers for oxidative damage can be observed in the pathogenic regions of the brain and the affected neurons. Model animal studies also showed oxidative damage associated with neuronal degeneration. The molecular imaging method with positron emission tomography (PET) is expected to delineate oxidatively stressed microenvironments to elucidate pathophysiological changes of the in vivo brain; however, only a few studies have successfully demonstrated enhanced stress in patients. Radioisotope copper labeled diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) may be the most promising candidate for this oxidative stress imaging. The tracer is usually known as a hypoxic tissue imaging PET probe, but the accumulation mechanism is based on the electron rich environment induced by mitochondrial impairment and/or microsomal over-reduction, and thus it is considered to represent the oxidative stress state correlated with the degree of disease severity. In this review, Cu-ATSM PET is introduced in detail from the basics to practical methods in clinical studies, as well as recent clinical studies on cerebrovascular diseases and neurodegenerative diseases. Several other PET probes are also introduced from the point of view of neuronal oxidative stress imaging. These molecular imaging methods should be promising tools to reveal oxidative injuries in various brain diseases.

Effects of Lactobacillus salivarius-containing tablets on caries risk factors: a randomized open-label clinical trial

Background

To evaluate the effects of the lactic acid bacterium Lactobacillus salivarius on caries risk factors.

Methods

The study was performed in 64 healthy volunteers to evaluate the effects of L. salivarius-containing tablets on caries risk factors. The participants were divided randomly into four groups, and took tablets containing L. salivarius WB21, L. salivarius TI 2711, Ovalgen® DC (antibody against glucosyltransferase from Streptococcus mutans), or xylitol. Levels of mutans streptococci and lactobacilli, amount of salivary flow, salivary pH, and salivary buffering capacity were assessed before and after taking the tablets. Subsequently, a short-term administration trial using L. salivarius WB21-containing tablets was performed in eight healthy volunteers. The participants took L. salivarius WB21-containing tablets (2.0 × 10⁹ colony forming units/day) for 2 weeks, and the numbers of mutans streptococci in saliva were counted.

Results

The levels of mutans streptococci seemed to decrease in the L. salivarius WB21, TI 2711, and Ovalgen® DC groups compared to the xylitol group, with no significant differences between the groups. Lactobacilli levels significantly increased in the L. salivarius WB21 and TI 2711 groups compared to the other groups. Concerning salivary flow and salivary pH, no significant differences were observed between the groups. The salivary buffering capacity significantly increased in the L. salivarius TI 2711 group (P = 0.003) and Ovalgen® DC group (P = 0.002) compared to the xylitol group. The short-term administration trial showed that the L. salivarius WB21-containing tablets significantly decreased the number of mutans streptococci (P = 0.039).

Conclusion

L. salivarius-containing tablets were suggested to increase resistance to caries risk factors.

Trial registration

UMIN000013160 (registration date: February 14, 2014).

Osteomyelitis and arthritis of the wrist caused by Mycobacterium intracellulare in an immunocompetent patient: a case report and literature review

Mycobacterium intracellulare causes infection in humans. Involvement of joint and bone, however, is extremely rare. We present the case of an immunocompetent 67-year-old female with chronic swelling of the wrist joint diagnosed as rheumatoid arthritis by her previous physician. Examination revealed an unclosed fistula associated with a puncture, and bone and joint destruction on radiographs. She was diagnosed with osteomyelitis and arthritis due to M. intracellulare on histological and microbiological examinations. She was successfully treated with radical surgical debridement and anti-tuberculous drugs for 1 year and there was no recurrence at 3 years postoperatively.

Huge tumor-like subacromial bursitis associated with rheumatoid arthritis

Abstract We report a rare case of a huge subacromial bursitis in rheumatoid arthritis. A solid tumor was initially suspected because it was very large with no apparent local sign of inflammation, and because no fluid retention was observed. We performed radiograms, a plain computed tomogram, a (99)mTc-MDP bone scintigram, a (67)Ga-citrate scintigram, and a digital subtraction arteriogram, which all indicated no evidence of tumor. Finally, a bursogram proved the mass to be a huge enlarged subacromial bursa. Surgical exploration revealed that the bursa contained 450 g of a yellowish, jelly-like substance, which was considered to be a thick collection of fibrin. No recurrence was noted at a follow-up 16 years after surgery.

Supervised machine learning-based classification of oral malodor based on the microbiota in saliva samples

OBJECTIVE

This study presents an effective method of classifying oral malodor from oral microbiota in saliva by using a support vector machine (SVM), an artificial neural network (ANN), and a decision tree. This approach uses concentrations of methyl mercaptan in mouth air as an indicator of oral malodor, and peak areas of terminal restriction fragment (T-RF) length polymorphisms (T-RFLPs) of the 16S rRNA gene as data for supervised machine-learning methods, without identifying specific species producing oral malodorous compounds.

METHODS

16S rRNA genes were amplified from saliva samples from 309 subjects, and T-RFLP analysis was carried out with the DNA fragments. T-RFLP analysis provides information on microbiota consisting of fragment lengths and peak areas corresponding to bacterial strains. The peak area is equivalent to the frequency of a specific fragment when one molecule is selected from terminal fragments. Another frequency is obtained by dividing the number of species-containing samples by the total number of samples. An SVM, an ANN, and a decision tree were trained based on these two frequencies in 308 samples and classified the presence or absence of methyl mercaptan in mouth air from the remaining subject.

RESULTS

The proportion that trained SVM expressed as entropy achieved the highest classification accuracy, with a sensitivity of 51.1% and specificity of 95.0%. The ANN and decision tree provided lower classification accuracies, and only classification by the ANN was improved by weighting with entropy from the frequency of appearance in samples, which increased the accuracy to 81.9% with a sensitivity of 60.2% and a specificity of 90.5%. The decision tree showed low classification accuracy under all conditions.

CONCLUSIONS

Using T-RF proportions and frequencies, models to classify the presence of methyl mercaptan, a volatile sulfur-containing compound that causes oral malodor, were developed. SVM classifiers successfully classified the presence of methyl mercaptan with high specificity, and this classification is expected to be useful for screening saliva for oral malodor before visits to specialist clinics. Classification by a SVM and an ANN does not require the identification of the oral microbiota species responsible for the malodor, and the ANN also does not require the proportions of T-RFs.

Clinical outcome of the chronic flexor tenosynovitis in the hand caused by non-tuberculous mycobacterium treated by extensive tenosynovectomy and drugs

Chronic flexor tenosynovitis in the hand caused by non-tuberculous mycobacterial (NTM) infection is uncommon. Although some authors have recommended combining surgical and drug therapy, there are few reports about the timing of drug administration after operation. The purpose of this retrospective study was to analyse the clinical outcome of the protocol, which consisted of extensive tenosynovectomy and drug therapy administered after culture results had been obtained. Four men and one woman were included. Average age was 57.4 years and average follow-up period was 46.7 months. Extensive tenosynovectomy was performed and surgical specimen was examined histopathologically and microbiologically. After a positive culture result had been obtained, three kinds of drugs were administered. Clinical outcome including infectious condition, range of motion, and grip strength was examined. All patients were immunocompetent and had no underlying disease. Three patients were diagnosed at first operation and two were diagnosed at second operation. The average period of drug therapy was 5.5 months. In four patients, infection resolved with combination therapy. In one patient with surgical treatment, only swelling remained. Osteomyelitis of the scaphoid was found in one patient to whom systemic steroid had been administered because of a negative culture result at first operation. For immunocompetent patients, flexor tenosynovitis in the hand caused by NTM was resolved with a combination of surgical and drug treatment. Drug treatment seemed to be essential after a reduction of the infectious lesion and the timing of administration was safe enough to resolve in four patients.

A case of pancreatic ductal adenocarcinoma with marked infiltration with IgG4-positive cells

A 75-year-old man was diagnosed as having pancreatic ductal carcinoma containing remarkable lymphocytic and plasma cell infiltration, as revealed by the cytological examination of endoscopic ultrasound guided fine-needle aspiration (EUS-FNA) specimen. The EUS-FNA specimen showed small amounts of atypical epithelium with noticeable lymphocytes and plasma cells. A pancreatic resection was performed, and the histopathological features showed an invasive pancreatic ductal carcinoma with autoimmune pancreatitis (AIP) lymphoplasmacytic sclerosing pancreatitis (LPSP)-like lesions. Most of the plasma cells were immunoreactive to anti-IgG4 antibody. EUS-FNA may be necessary for the differential diagnosis of AIP and pancreatic cancer, and close attention should be given to the presence of marked lymphoplasmacytic cells in EUS-FNA specimens while making the diagnosis.

Mixed red-complex bacterial infection in periodontitis

The red complex, which includes Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia (formerly Bacteroides forsythus), are recognized as the most important pathogens in adult periodontal disease. These bacteria are usually found together in periodontal pockets, suggesting that they may cause destruction of the periodontal tissue in a cooperative manner. This article discusses the interspecies pathogenic interactions within the red complex.

Protection from non-alcoholic steatohepatitis and liver tumourigenesis in high fat-fed insulin receptor substrate-1-knockout mice despite insulin resistance

AIMS/HYPOTHESIS

Epidemiological studies have revealed that obesity and diabetes mellitus are independent risk factors for the development of non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma. However, the debate continues on whether insulin resistance as such is directly associated with NASH and liver tumourigenesis. Here, we investigated the incidence of NASH and liver tumourigenesis in Irs1 ( -/- ) mice subjected to a long-term high-fat (HF) diet. Our hypothesis was that hepatic steatosis, rather than insulin resistance may be related to the pathophysiology of these conditions.

METHODS

Mice (8 weeks old, C57Bl/6J) were given free access to standard chow (SC) or an HF diet. The development of NASH and liver tumourigenesis was evaluated after mice had been on the above-mentioned diets for 60 weeks. Similarly, Irs1 ( -/- ) mice were also subjected to an HF diet for 60 weeks.

RESULTS

Long-term HF diet loading, which causes obesity and insulin resistance, was sufficient to induce NASH and liver tumourigenesis in the C57Bl/6J mice. Obesity and insulin resistance were reduced by switching mice from the HF diet to SC, which also protected these mice against the development of NASH and liver tumourigenesis. However, compared with wild-type mice fed the HF diet, Irs1 ( -/- ) mice fed the HF diet were dramatically protected against NASH and liver tumourigenesis despite the presence of severe insulin resistance and marked postprandial hyperglycaemia.

CONCLUSIONS/INTERPRETATION

IRS-1 inhibition might protect against HF diet-induced NASH and liver tumourigenesis, despite the presence of insulin resistance.

Measles virus selectively blind to signaling lymphocyte activation molecule as a novel oncolytic virus for breast cancer treatment

Oncolytic viruses hold much promise as novel therapeutic agents that can be combined with conventional therapeutic modalities. Measles virus (MV) is known to enter cells using the signaling lymphocyte activation molecule (SLAM), which is expressed on cells of the immune system. Although human breast cancer cell lines do not express SLAM, we found that a wild-type MV (HL strain) efficiently infected various breast cancer cell lines, causing cell death. Based on this finding, we used reverse genetics to generate a recombinant MV selectively unable to use SLAM (rMV-SLAMblind). The rMV-SLAMblind lacked infectivity for SLAM-positive lymphoid cells, while retaining oncolytic activity against breast cancer cells. We showed that, unlike the MV vaccine strains, rMV-SLAMblind used PVRL4 (polio virus receptor-related 4) as a receptor to infect breast cancer cells and not the ubiquitously expressed CD46. Consistent with this, rMV-SLAMblind infected CD46-positive primary normal human cells at a much-reduced level, whereas a vaccine strain of the Edmonston lineage (rMV-Edmonston) efficiently infected and killed them. The rMV-SLAMblind showed antitumor activity against human breast cancer xenografts in immunodeficient mice. The oncolytic activity of rMV-SLAMblind was significantly greater than that of rMV-Edmonston. To assess the in vivo safety, three monkeys seronegative for MV were inoculated with rMV-SLAMblind, and no clinical symptoms were documented. On the basis of these results, rMV-SLAMblind could be a promising candidate as a novel oncolytic virus for breast cancer treatment.