Intracellular stress caused by composite resins: An in vitro study using a bioluminescent antioxidant-responsive element reporter assay.

Context: Elucidating the effects of leachates from composite resins (CRs) on cells by examining the transcription level of detoxification genes and the antioxidant-responsive element (ARE), would be helpful in clinical practice. Aims: The aim of the study is to investigate the cytotoxicity of commercially available CRs, we used a reporter assay system to evaluate intracellular stress based on ARE-mediated transcription. Setting and Design: The study design was an in vitro study. Materials and Methods: Seven kinds of CRs were each placed in four-well plates to which culture medium was added and then light-cured. The prepared samples were used either immediately (sample A) or after incubation at 37°C for 24 h (sample B) in the subsequent ARE-luciferase reporter assay, in which HepG2 cells stably expressing an ARE-regulated luciferase reporter gene (HepG2-AD13 cells) were cultured for 6 h in culture media with the CR eluate (samples A or B) or without (control) (n = 4). In the cell viability assay, cell viability in various solutions with the same incubation time was confirmed by MTT assay (n = 4). Statistical analysis was performed using the paired t-test and one-way analysis of variance. Results: All CR solutions showed an increase in ARE activation rate; a CR with spherical nanofillers showed the highest ARE activation rate of 108.5-fold in sample A. Cell viability was not significantly reduced for any of the CRs in sample A. However, the CR-containing bisphenol A-glycidyl methacrylate (Bis-GMA) caused a significant decrease in cell viability in sample B. Conclusions: The intracellular stress in the viable cells differed among the CRs, depending on the type of monomer used. In particular, Bis-GMA-containing hydroxyl groups showed high cytotoxicity.

Rapid Whole-Body FDG PET/MRI in Oncology Patients: Utility of Combining Bayesian Penalised Likelihood PET Reconstruction and Abbreviated MRI.

This study evaluated the diagnostic value of a rapid whole-body fluorodeoxyglucose (FDG) positron emission tomography (PET)/magnetic resonance imaging (MRI) approach, combining Bayesian penalised likelihood (BPL) PET with an optimised ß value and abbreviated MRI (abb-MRI). The study compares the diagnostic performance of this approach with the standard PET/MRI that utilises ordered subsets expectation maximisation (OSEM) PET and standard MRI (std-MRI). The optimal ß value was determined by evaluating the noise-equivalent count (NEC) phantom, background variability, contrast recovery, recovery coefficient, and visual scores (VS) for OSEM and BPL with ß100-1000 at 2.5-, 1.5-, and 1.0-min scans, respectively. Clinical evaluations were conducted for NECpatient, NECdensity, liver signal-to-noise ratio (SNR), lesion maximum standardised uptake value, lesion signal-to-background ratio, lesion SNR, and VS in 49 patients. The diagnostic performance of BPL/abb-MRI was retrospectively assessed for lesion detection and differentiation in 156 patients using VS. The optimal ß values were ß600 for a 1.5-min scan and ß700 for a 1.0-min scan. BPL/abb-MRI at these ß values was equivalent to OSEM/std-MRI for a 2.5-min scan. By combining BPL with optimal ß and abb-MRI, rapid whole-body PET/MRI could be achieved in ≤1.5 min per bed position, while maintaining comparable diagnostic performance to standard PET/MRI.

Physiological skin FDG uptake: A quantitative and regional distribution assessment using PET/MRI.

PURPOSE: To retrospectively assess the repeatability of physiological F-18 labeled fluorodeoxyglucose (FDG) uptake in the skin on positron emission tomography/magnetic resonance imaging (PET/MRI) and explore its regional distribution and relationship with sex and age. METHODS: Out of 562 examinations with normal FDG distribution on whole-body PET/MRI, 74 repeated examinations were evaluated to assess the repeatability and regional distribution of physiological skin uptake. Furthermore, 224 examinations were evaluated to compare differences in the uptake due to sex and age. Skin segmentation on PET was performed as body-surface contouring on an MR-based attenuation correction map using an off-line reconstruction software. Bland-Altman plots were created for the repeatability assessment. Kruskal-Wallis test was performed to compare the maximum standardized uptake value (SUVmax) with regional distribution, age, and sex. RESULTS: The limits of agreement for the difference in SUVmean and SUVmax of the skin were less than 30%. The highest SUVmax was observed in the face (3.09±1.04), followed by the scalp (2.07±0.53). The SUVmax in the face of boys aged 0-9 years and 10-20 years (1.33±0.64 and 2.05±1.00, respectively) and girls aged 0-9 years (0.98±0.38) was significantly lower than that of men aged ≥20 years and girls aged ≥10 years (p<0.001). In women, the SUVmax of the face (2.31±0.71) of ≥70-year-olds was significantly lower than that of 30-39-year-olds (3.83±0.82) (p<0.05). CONCLUSION: PET/MRI enabled the quantitative analysis of skin FDG uptake with repeatability. The degree of physiological FDG uptake in the skin was the highest in the face and varied between sexes. Although attention to differences in body habitus between age groups is needed, skin FDG uptake also depended on age.

A new oral care gel to prevent aspiration during oral care.

AIM: Although oral care is important in the prevention of aspiration pneumonia, the different institutions and practitioners employ various oral care methods, some of which are associated with the risk of aspiration. We have developed a new gel with the physical properties needed for waterless oral care. In the present study, we evaluated and investigated the properties and effectiveness of this gel. METHODS: The physical properties of the trial gel and commercial moisturizing gels were compared using a VAS scale. The effects of plaque elimination were evaluated in healthy volunteers. Brushing was carried out by a dental hygienist using the gel and water. The number of throat suctions performed during brushing was also counted, and the difference was evaluated. RESULTS: In the evaluation of physical characteristics, trial Gel B showed a significantly higher rating than the other gels. In plaque elimination, the rate of decrease in a modified PCR was significantly greater with the gel trial. Suctioning was also performed significantly fewer times with the trial gel. CONCLUSIONS: Good results were obtained with the newly developed trial Gel B with regard to the physical properties and the sensory evaluations. Its effectiveness was also confirmed in plaque elimination and in the evaluated risk of aspiration. The use of Gel B may have the potential to decrease the risk of aspiration during oral care and reduce the occurrence of aspiration pneumonia.

Comparison of clinical practice education in dental hygiene schools in eight countries.

OBJECTIVES: The profession of dental hygienist is one of the few in which the primary function of the practitioner is to prevent oral disease and to promote the well-being of patients. The aim of this study was to investigate clinical training conditions in schools of dental hygiene in eight countries (the USA, Canada, the UK, Sweden, Denmark, Thailand, South Korea and Japan). METHODS: In 2006, we sent out a questionnaire in which we asked dental hygiene schools about how they educate dental hygiene students. RESULTS: The techniques taught to students in schools in Western industrialised nations, such as the USA, Canada, Denmark, the UK and Sweden, were mainly related to dental preventive measures and dental health guidance. By contrast, training schools in South Korea and Japan placed less emphasis on dental preventive measures and dental health guidance. Dental hygienists in Thailand are trained to perform local anaesthesia and to fill and extract deciduous teeth although the country does not have a specific qualification system. CONCLUSIONS: The contents of clinical training and education in schools of dental hygiene differ greatly among countries.

Recent trends in sugar content and pH in contemporary soft drinks.

PURPOSE: The purpose of this study was to determine the content of sucrose, glucose, total sugar, and pH in a range of popular contemporary Japanese soft drinks and compare their changes in different periods. METHODS: The pH value and content of sucrose and glucose of popular Japanese soft drinks were determined, and this study's results were compared with the previous data of beverages in 1978, 1981, 1985, and 1997. RESULTS: Coffee drinks showed the highest content of sucrose, while carbonated diet drinks showed the lowest. Energy drinks showed the highest content of glucose and total sugar, while carbonated diet drinks showed the lowest. Coffee and energy drinks showed the highest and lowest pH levels, respectively. The total sugar content of a soft drink has remained unchanged over the years, but the sucrose content of soft drinks has decreased over the years. CONCLUSIONS: All drinks showed pH values below 7, with a very wide variety of sugar content; sugar content of soft drinks has generally decreased since the 1980s in Japan.

Remineralization of primary tooth enamel from individuals with Down syndrome.

PURPOSE: The purpose of this study was to clarify the characteristics of primary tooth enamel of Down syndrome patients (DSPs). We examined 9 primary teeth of Down syndrome children and 11 primary teeth of normally developed children to investigate the remineralization processes of enamel by transverse microradiography and X ray micro analyzer (XMA). METHODS: Mineral loss, lesion depth, maximum mineral value, minimum mineral value, depth of maximum mineral value, and depth of minimum mineral value were used to analyze transverse microradiography (TMR). In addition, we calculated the percentage of enamel remineralization. RESULTS: All the parameters in the 2 groups showed marked recovery. The results indicated that the Down syndrome group was significantly remineralized the same way as the control group. According to the comparison of mineral content distribution by XMA, the content distribution of magnesium was different between the 2 groups. CONCLUSION: While recovery through remineralization of primary teeth was similar between Down syndrome children and normally developed children, the mechanism of remineralization process may be different between the 2 groups; consequently, magnesium may be considered as one of the factors affecting recovery.

Temporal association of elevated C-reactive protein and periodontal disease in men.

BACKGROUND: Most studies on the relationship between serum C-reactive protein (CRP) and periodontal disease have been cross-sectional. In this study, we investigated the temporal association between CRP and periodontal disease by following a large number of subjects for 1 year. METHODS: We studied 11,162 men in Nagoya, Japan, who had an initial dental examination as part of a complete physical examination and then underwent the same examination 1 year later. For the 4,997 men without periodontal disease at baseline, logistic regression analysis was performed to examine the relationship between baseline CRP and periodontal disease 1 year later, adjusting for age, body mass index, glycosylated hemoglobin A1c level, and smoking status. Similarly, logistic regression analysis was performed to examine the relationship between periodontal disease at baseline and CRP 1 year later for the 10,376 men with normal baseline CRP, adjusting for the same confounding factors. RESULTS: Among men without high CRP at baseline, periodontal disease at baseline correlated to CRP 1 year later. The odds ratio was 1.336 (95% confidence interval [CI]: 1.115 to 1.674). However, in the men without periodontal disease, no significant correlations were seen with baseline CRP or periodontal disease 1 year later. The odds ratio was 1.163 (95% CI: 0.894 to 1.513). CONCLUSION: Periodontal disease increased the risk for high serum CRP levels in men after 1 year of follow-up.

Effect of strontium in combination with fluoride on enamel remineralization in vitro.

Previous studies showed that strontium (Sr) as well as fluoride (F) can enhance enamel remineralization. The aim of this study was to evaluate the effects of Sr in combination with F on enamel remineralization in vitro. Sixty enamel specimens obtained from caries free human premolars were demineralised to produce caries-like lesions. Half of each lesion was covered with nail varnish as an untreated control. The specimens were then randomly divided into F and Sr+F treatment groups. The F group was exposed to remineralizing solutions (1.5mM CaCl(2), 0.9 mM KH(2)PO(4)) containing 1 ppm, 0.1 ppm or 0.05 ppm F. The Sr+F treatment group was exposed to the same solutions including 10 ppm Sr. After 2 weeks, lesion depth, mineral loss and percentage enamel remineralization were determined using transversal microradiography. There was a significant decrease in mineral loss in all groups (p<0.001). Lesion depth was significantly reduced for all groups (p<0.05) with the exception of group F. Remineralization was significantly affected by F concentration (p=0.000). The participation of Sr resulted in a significant enhancement of remineralization (p<0.001) with a synergistic effect of the Sr+F combination (p<0.01). It was concluded that while the remineralizing process was affected by the concentration of F, there was also an interaction between F and Sr when they were used in conjunction.