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Featured researches published by Takashi Zaitsu.


Journal of Periodontal Research | 2011

Clinical trial of oral malodor treatment in patients with periodontal diseases

Thuy A.V. Pham; Masayuki Ueno; Takashi Zaitsu; Sachiko Takehara; Kayoko Shinada; P. H. Lam; Yoko Kawaguchi

BACKGROUND AND OBJECTIVE Only a few clinical research studies have assessed different therapeutic approaches to oral malodor in subjects affected by periodontal diseases. The aim of this study was to evaluate the effects of periodontal treatment and tongue cleaning on oral malodor parameters in periodontitis and gingivitis patients. MATERIAL AND METHODS The subjects were 102 periodontitis and 116 gingivitis patients with oral malodor. Oral malodor was measured by organoleptic test and Oral Chroma™. Oral health status, including tooth conditions, periodontal health, tongue coating and proteolytic activity of the BANA test in tongue coating were assessed. Subjects in each periodontal disease group were randomly assigned into two subgroups depending on the sequence of treatment: periodontal treatment and tongue cleaning. Oral malodor and oral health parameters were compared by groups and sequence of treatment. RESULTS For subjects in the periodontitis group, there were statistically significant reductions in oral malodor after periodontitis treatment or tongue cleaning; however, major reductions were found after periodontitis treatment. For those in the gingivitis group, there were also statistically significant reductions in oral malodor after gingivitis treatment or tongue cleaning, but the most marked reductions were observed after tongue cleaning. At the completion of treatment, all oral malodor parameters fell below the threshold levels in all subgroups. CONCLUSION The present study indicated that periodontal treatment played an important role and tongue cleaning contributed to a lesser extent to reduction in oral malodor in periodontitis patients. In contrast, tongue cleaning alone can be the primary approach to reduce oral malodor in gingivitis patients.


Trials | 2010

Effects of a mouthwash with chlorine dioxide on oral malodor and salivary bacteria: a randomized placebo-controlled 7-day trial

Kayoko Shinada; Masayuki Ueno; Chisato Konishi; Sachiko Takehara; Sayaka Yokoyama; Takashi Zaitsu; Mari Ohnuki; Fredrick Allan Clive Wright; Yoko Kawaguchi

BackgroundPrevious research has shown the oxidizing properties and microbiological efficacies of chlorine dioxide (ClO2). Its clinical efficacies on oral malodor have been evaluated and reported only in short duration trials, moreover, no clinical studies have investigated its microbiological efficacies on periodontal and malodorous bacteria. Thus, the aim of this study was to assess the inhibitory effects of a mouthwash containing ClO2 used for 7 days on morning oral malodor and on salivary periodontal and malodorous bacteria.Methods/DesignA randomized, double blind, crossover, placebo-controlled trial was conducted among 15 healthy male volunteers, who were divided into 2 groups. Subjects were instructed to rinse with the experimental mouthwash containing ClO2 or the placebo mouthwash, without ClO2, twice per day for 7 days. After a one week washout period, each group then used the opposite mouthwash for 7 days. At baseline and after 7 days, oral malodor was evaluated with Organoleptic measurement (OM), and analyzed the concentrations of hydrogen sulfide (H2S), methyl mercaptan (CH3SH) and dimethyl sulfide ((CH3)2S), the main VSCs of human oral malodor, were assessed by gas chromatography (GC). Clinical outcome variables included plaque and gingival indices, and tongue coating index. The samples of saliva were microbiologically investigated. Quantitative and qualitative analyses were performed using the polymerase chain reaction-Invader method.Results and DiscussionThe baseline oral condition in healthy subjects in the 2 groups did not differ significantly. After rinsing with the mouthwash containing ClO2 for 7 days, morning bad breath decreased as measured by the OM and reduced the concentrations of H2S, CH3SH and (CH3)2S measured by GC, were found. Moreover ClO2 mouthwash used over a 7-day period appeared effective in reducing plaque, tongue coating accumulation and the counts of Fusobacterium nucleatum in saliva. Future research is needed to examine long-term effects, as well as effects on periodontal diseases and plaque accumulation in a well-defined sample of halitosis patients and broader population samples.Trial registrationClinicalTrials.gov NCT00748943


Journal of nutrition in gerontology and geriatrics | 2011

Oral health status and chewing ability is related to mini-nutritional assessment results in an older adult population in Thailand.

Patcharaphol Samnieng; Masayuki Ueno; Kayoko Shinada; Takashi Zaitsu; Fredrick Allan Clive Wright; Yoko Kawaguchi

In a cross-sectional study, we investigated the relationship of Mini-Nutrition Assessment (MNA) results with chewing ability tests and oral examinations (number of teeth present and functional tooth units (FTUs)). The participants were 612 older people (Mean [SD] age: 68.8 [5.9]). According to the MNA score, 25.1% of participants were categorized as having normal nutrition, 67.2% were categorized as at risk of malnourishment, and 7.7% were categorized as having malnutrition. The mean numbers of teeth present and FTUs were [15.5] and [8.9], respectively. The ANCOVA analyses adjusted for age and gender showed that participants with malnutrition had lower numbers of teeth present (8.8), FTUs (8.4), and chewing ability (6.8) than those with normal nutrition (13.3, 10.4 and 7.8) (p < 0.05). Nutritional status was associated with mean numbers of teeth present, FTUs, and chewing ability. Therefore, it was concluded that retention of natural teeth with appropriate numbers of FTUs by replacing missing teeth with dentures and improving chewing ability will help the reduce risk of malnutrition in older adults.


Trials | 2015

Effectiveness of three oral hygiene regimens on oral malodor reduction: a randomized clinical trial.

Ei Ei Aung; Masayuki Ueno; Takashi Zaitsu; Sayaka Furukawa; Yoko Kawaguchi

BackgroundBreath odor is a nuisance problem for many people around the world. Bad breath affects social interactions of people in daily life by causing personal discomfort and emotional stress. There are chemical and mechanical methods for controlling oral malodor. Many studies of various mouth rinse applications and tongue cleaning procedures have been conducted. However, few studies have compared the effect of simultaneous chemical and mechanical procedures on the reduction of volatile sulfur compounds (VSCs) in subjects with oral malodor. The purpose of this study was to assess the effects of different oral hygiene procedures on reduction of VSCs in subjects with oral malodor.MethodsThirty male volunteers who matched with study criteria were divided randomly into two groups. Both groups performed tooth brushing, mouth washing with chlorine dioxide, tongue cleaning and combination of those in different sequence for five weeks. Total VSCs of subjects were measured with a Breathtron®, and oral health status was also examined. Quantitative analyses were performed using the Statistical Package for Social Science (SPSS 16.0).ResultsThere were no significant differences in oral health status between the two groups at the baseline. No significant decrease in oral malodor was detected after one week of tooth brushing. Significant reductions in VSCs were shown by adding mouthwash or tongue cleaning to tooth brushing from the second week to fourth week (P <0.01). The greatest reduction in VSCs was found at the fifth week after the practice of all three oral hygiene regimens.ConclusionsTooth brushing alone does not significantly reduce oral malodor. Mouth washing and tongue cleaning significantly reduce oral malodor, but combining tooth brushing, mouth washing and tongue cleaning regimens is most effective for oral malodor reduction. The results of this study could contribute to the formulation of appropriate preventive strategies against oral malodor not only for the general public but also for dental professionals serving as oral malodor-related service providers.Trial registrationRegistration number - ClinicalTrials.gov NCT02113137. Registration date – April 7th, 2014.


Acta Odontologica Scandinavica | 2012

Effects of an oral health education program targeting oral malodor prevention in Japanese senior high school students

Masayuki Ueno; Kayoko Shinada; Takashi Zaitsu; Sayaka Yokoyama; Yoko Kawaguchi

Abstract Objective. Previous research has suggested that oral malodor could be a useful motivational tool for increasing the awareness of oral health in adolescents and improving their oral health behaviors. Hence, the aims of this research were: (1) to develop an oral health education program that included oral malodor prevention and (2) to test the effects of the program in Japanese senior high school students by comparing the changes of oral health outcomes between the intervention and control groups. Materials and methods. Subjects were 163 Grade 1 and 135 Grade 2 senior high school students in Tokyo, Japan. A novel oral health education program, which incorporated prevention of oral malodor, was developed and conducted on all Grade 1 students (intervention group). Grade 2 students (control group) did not receive the program. Changes in oral health status from baseline to 1-year follow-up were compared between the intervention and control groups. Results. The intervention group, compared with the control group, had a significantly higher proportion of students who improved or maintained good oral health status (i.e. dental plaque, gingivitis, tongue coating and oral malodor). Among students in the intervention group, the change was more evident in subjects with detectable oral malodor at the commencement of the program. Conclusions. An oral health education program focusing on the prevention of oral malodor is effective for promoting oral health among Japanese senior high school students. Therefore, embedding such a program in the school oral health curriculum would be beneficial for adolescents.


Gerodontology | 2012

Daily variation of oral malodour and related factors in community-dwelling elderly Thai

Patcharaphol Samnieng; Masayuki Ueno; Kayoko Shinada; Takashi Zaitsu; Yoko Kawaguchi

OBJECTIVES The purposes of this study were (i) to estimate the prevalence of oral malodour, (ii) to evaluate the daily variation of oral malodour and (iii) to assess associations of volatile sulphur compound (VSC) concentrations with socio-demographics, health behaviours and oral health status in community-dwelling elderly Thai. METHODS The subjects were 428 dentate elderly people (67.6 ± 5.6 years) living in Phitsaulok, Thailand. Information on their socio-demographics, general health and health behaviours was obtained by a questionnaire. Their dental condition, periodontal status and tongue coating were clinically examined. Their flow rates and the pH of unstimulated saliva were also assessed. Oral malodour was measured at four different times of day using an Oral Chroma™. RESULTS The proportions of subjects diagnosed with oral malodour using the thresholds of H(2)S, CH(3)SH and (CH(3))(2) S were 60.5%, 62.9% and 80.7%, respectively. Concentrations of H(2)S showed significant daily variation. Linear regression analysis demonstrated the following significant associations: (i) oral malodour from H(2)S and thickness of the tongue coating, (ii) oral malodour from CH(3)SH and periodontal pocket depth of 5 mm or more and the presence of gingival bleeding and (iii) oral malodour from (CH(3))(2)S and systemic disease, medications and thickness of the tongue coating. DISCUSSION Oral malodour was shown to be prevalent among the elderly. Daily variation was observed in the concentration of H(2)S. Tongue coating, periodontal disease, systemic diseases and medications were related to oral malodour. Therefore, these factors should be taken into consideration in oral malodour treatment and prevention programmes for the elderly.


BMC Oral Health | 2014

Taste hyposensitivity in Japanese schoolchildren

Mari Ohnuki; Masayuki Ueno; Takashi Zaitsu; Yoko Kawaguchi

BackgroundThere is some research on taste disorder/hyposensitivity in special groups such as the elderly or patients presenting with specific taste problems, however few studies have been conducted among young populations. The objectives of this study were to estimate the prevalence of taste hyposensitivity and to investigate the relationship between taste hyposensitivity and oral health status in Japanese schoolchildren.MethodsSubjects were 237 primary and 112 junior high school students in Saitama Prefecture, Japan. In total, 349 (boys: 181, girls: 168) students aged 6–15 years participated in the study. Oral examinations and whole-mouth taste tests using four tastes (sweet, salt, sour and bitter) solutions were conducted on the subjects. A subject who could not recognize the taste of the solution was defined as demonstrating hyposensitivity.ResultsHyposensitivity was observed in 6.3% of all subjects for sweet-taste, 14.3% for salt-taste, 20.9% for sour-taste and 6.0% for bitter-taste. The prevalence of sweet, sour and bitter-taste hyposensitivity decreased as the subjects’ grade advanced. In contrast, the prevalence of salt-taste hyposensitivity increased in 7th-9th grade subjects. Furthermore, the prevalence of bitter-taste hyposensitivity was significantly higher in males than females among 1st-3rd graders.Taste hyposensitivity had little association with oral health status, such as decayed teeth, filled teeth, dental plaque, gingival status and tongue coating.ConclusionsIn this study, taste hyposensitivity was observed in 6.0%-20.9% of the students. There was little association between taste hyposensitivity and oral health status. The current study implies that the factors affecting the taste hyposensitivity in children may different from those in the elderly. Therefore it is necessary to further investigate the causes of taste hyposensitivity among younger generation.


Gerodontology | 2013

The relationship between seven health practices and oral health status in community-dwelling elderly Thai.

Patcharaphol Samnieng; Masayuki Ueno; Takashi Zaitsu; Kayoko Shinada; Fredrick Allan Clive Wright; Yoko Kawaguchi

OBJECTIVE This study aims to analyse the relationship between seven health practices, oral health behaviors, and oral health status in community dwelling elderly Thai. MATERIALS AND METHODS The subjects were 612 elderly people (mean age = 68.8 ± 5.9 years). Questionnaires survey about sociodemographics, self-reported seven health practices and oral health behaviors were conducted by trained interviewers. Oral examinations investigated the number of teeth present, decayed teeth, periodontal status and functional tooth units (FTUs). Oral malodor was assessed by Organoleptic Test, and unstimulated saliva was collected for 5 min. RESULTS Five health practices (smoking, drinking, physical activity, breakfast and weight maintenance) were significantly related with oral health behaviors. ancova analysis demonstrated the following significant associations: (i) smoking behavior with number of teeth present, number of FTUs, decayed teeth, periodontal disease, oral malodor and salivary flow rate, (ii) drinking alcohol behavior with number of teeth present, number of FTUs, periodontal disease, oral malodor and salivary flow rate, (iii) eating breakfast behavior with periodontal disease, oral malodor and salivary flow rate, (iv) eating between-meal snack with number of teeth present, number of FTUs, decayed teeth and periodontal disease, (v) maintaining weight with number of teeth present, number of FTUs, periodontal disease and oral malodor, (vi) sleeping with number of teeth present, number of FTUs, periodontal disease, oral malodor and salivary flow rate, (vii) physical activity with periodontal disease and salivary flow rate. CONCLUSION Good health practices were related with good oral health behaviors. Moreover, general health practices were associated with the clinical oral health status such as number of teeth present, decayed teeth, FTUs, periodontal disease, oral malodor and salivary flow rate. The elderly with good general health practices were considered to have good oral health status. Improving general health habits are suggested to lead to better oral health for the elderly, and vice versa.


Asia-Pacific Journal of Public Health | 2015

Factors influencing perceived oral health of Japanese middle-aged adults.

Masayuki Ueno; Takashi Zaitsu; Satoko Ohara; Clive Wright; Yoko Kawaguchi

The objective of this study was to analyze the relationships between subjective oral health symptoms and clinical oral health conditions on the perceived oral health of 1799 Japanese middle-aged adults. A self-administered questionnaire together with dental examinations was administered. A structural equation modeling analysis with Bayesian estimation was used to examine the factors influencing perceived oral health as a latent variable with 4 other latent variables: subjective oral health symptoms, clinical tooth conditions, clinical periodontal conditions, and other clinical oral conditions. For perceived oral health as the endogenous variable, only subjective oral health symptoms and clinical tooth conditions showed significant relationship. Clinical periodontal conditions and other clinical oral conditions did not show significant effects on the perceived oral health.


Journal of Investigative and Clinical Dentistry | 2012

Exploring taste hyposensitivity in Japanese senior high school students

Mari Ohnuki; Kayoko Shinada; Masayuki Ueno; Takashi Zaitsu; Fredrick Allan Clive Wright; Yoko Kawaguchi

AIM The main objective of this study was to investigate the prevalence of taste hyposensitivity and the relationships between sex, oral health status, and eating habits with taste hyposensitivity in Japanese senior high school students. METHODS Oral examinations, sweet and salt whole-mouth taste tests, and a questionnaire about eating habits were conducted on 234 senior high school students. Factors affecting taste hyposensitivity were investigated using a multivariate analysis. RESULTS Sweet-taste hyposensitivity was observed in 7.3% of the students, and salt-taste hyposensitivity in 22.2%. Approximately 3% of the students had both sweet- and salt-taste hyposensitivity, and 22.6% had either sweet- or salt-taste hyposensitivity. In total, 26% had a taste hyposensitivity. There were significant relationships between the intake of instant noodles with sweet-taste hyposensitivity, and the intake of vegetables or isotonic drinks with salt-taste hyposensitivity. CONCLUSIONS There was a significant association between eating habits and taste hyposensitivity in Japanese senior high school students. Taste tests would be a helpful adjunct for students to recognize variations in taste sensitivity, and a questionnaire about their eating habits might provide an effective self-review of their eating habits, and therefore, provide motivation to change.

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Yoko Kawaguchi

Tokyo Medical and Dental University

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Masayuki Ueno

Tokyo Medical and Dental University

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Kayoko Shinada

Tokyo Medical and Dental University

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Mari Ohnuki

Tokyo Medical and Dental University

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Sachiko Takehara

Tokyo Medical and Dental University

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Ei Ei Aung

Tokyo Medical and Dental University

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Fredrick Allan Clive Wright

Tokyo Medical and Dental University

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Sayaka Furukawa

Tokyo Medical and Dental University

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Ayumi Takayama

Tokyo Medical and Dental University

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Satoko Ohara

Tokyo Medical and Dental University

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