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Featured researches published by Miki Ojima.


Oral Microbiology and Immunology | 2008

Relationship of Porphyromonas gingivalis with glycemic level in patients with type 2 diabetes following periodontal treatment

N. Makiura; Miki Ojima; Yurong Kou; Nobumichi Furuta; Nobuo Okahashi; Satoshi Shizukuishi; Atsuo Amano

INTRODUCTION The aim of this study was to assess the relationship between serum glycemic levels and subgingival microbial profile alteration following periodontal treatment in patients with type 2 diabetes mellitus. METHODS We studied 30 periodontitis patients with type 2 diabetes mellitus who received full-mouth subgingival debridement by analyzing their subgingival microbial profiles using a polymerase chain reaction method at baseline and various time-points for 12 months following treatment. Concurrently, probing pocket depth, bleeding on probing, and metabolic parameters, including glycated hemoglobin A1c (HbA1c), blood sugar level, C-reactive proteins, total cholesterol, triglyceride, and high-density and low-density lipoprotein cholesterol, were recorded. RESULTS Periodontal conditions were significantly improved after treatment, and the occurrence rates of periodontal bacterial species, including Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, and Prevotella intermedia, were also reduced. Interestingly, P. gingivalis was detected more frequently in subjects with increased HbA1c values after periodontal treatment than in those patients with decreased HbA1c values. Furthermore, P. gingivalis with type II fimbriae was detected only in HbA1c-increased subjects, while improvements in HbA1c values were observed only in subjects without type II clones. CONCLUSIONS These results suggest that glycemic level in diabetes is affected by the persistence of P. gingivalis, especially clones with type II fimbriae, in periodontal pockets.


BMC Public Health | 2011

Causal assessment of smoking and tooth loss: A systematic review of observational studies

Takashi Hanioka; Miki Ojima; Keiko Tanaka; Keitaro Matsuo; Fumihito Sato; Hideo Tanaka

BackgroundTooth loss impairs oral function. The aim of the present review was to evaluate the causal association between smoking and tooth loss on the basis of high-quality studies.MethodsRelevant literature was searched and screened, and the methodological quality was assessed. Information on the strength of the association between smoking and tooth loss, the dose-response relationship and natural experimental data was collected and evaluated with respect to consistency and study design.ResultsOur literature search yielded 496 citations, and 6 cross-sectional and 2 cohort high-quality studies examining 58,755 subjects in four countries. All studies reported significant associations, although the strength of the association was usually moderate. Four studies reported dose-response relationships between exposure to smoking and the risk of developing tooth loss. A decrease in the risk of tooth loss for former smokers was evident in six studies. Interpretation of evidence for each element was consistent, despite some shortcomings regarding study type and population.ConclusionsBased on the consistent evidence found with the existing biological plausibility, a causal association between smoking and tooth loss is highly likely. Further studies using a cohort design and different populations are necessary to confirm this association.


Molecular Aspects of Medicine | 1994

Effect of topical application of Coenzyme Q10 on adult periodontitis

Takashi Hanioka; Muneo Tanaka; Miki Ojima; Satoshi Shizukuishi; Karl Folkers

Topical application of Coenzyme Q10 (CoQ10) to the periodontal pocket was evaluated with and without subgingival mechanical debridement. Ten male patients with adult periodontitis participated and 30 periodontal pockets were selected. During the first 3 weeks, the patients did not receive any periodontal therapy except the topical application of CoQ10. After the first 3-week period, root planning and subgingival scaling were performed in all sites. CoQ10 was applied in 20 of the pockets once a week for a period of 6 weeks. Soybean oil was applied to the remaining 10 sites as a control. In the first 3-week period, significant reductions in gingival crevicular fluid flow, probing depth and attachment loss were found only at experimental sites. After mechanical subgingival debridement, significant decreases in the plaque index, gingival crevicular fluid flow, probing depth and attachment loss were found both at experimental and control sites. However, significant improvements in the modified gingival index, bleeding on probing and peptidase activity derived from periodontopathic bacteria were observed only at experimental sites. These results suggest that topical application of CoQ10 improves adult periodontitis not only as a sole treatment but also in combination with traditional nonsurgical periodontal therapy.


Tobacco Induced Diseases | 2010

Destructive effects of smoking on molecular and genetic factors of periodontal disease

Miki Ojima; Takashi Hanioka

Many epidemiological evidences have proven the association between smoking and periodontal disease. The causality can be further established by linking findings of traditional epidemiological studies with the developments in molecular techniques that occurred in the last decade. The present article reviews recent studies that address the effect of smoking on molecular and genetic factors in periodontal disease. Most findings support the fact that tobacco smoking modulates destruction of the periodontium through different pathways: microcirculatory and host immune systems, connective tissue, and bone metabolism. Although smokers experience an increased burden of inflammatory responses to microbial challenges compared to non-smokers, understanding the association between smoking and periodontal diseases involves substantial problems with respect to accuracy of measurements, and particularly, sampling of many subjects. It remains unclear whether genetic susceptibility to periodontal disease is influenced by exposure to smoking or the effect of smoking on periodontal disease is influenced by genetic susceptibility. Employment of molecular techniques may play a key role in further elucidation of mechanisms linking smoking and periodontal destruction, the direct relationship as environmental factors and indirect relationship through genetic factors.


Journal of Epidemiology | 2007

Relationship between smoking status and tooth loss : Findings from national databases in Japan

Takashi Hanioka; Miki Ojima; Keiko Tanaka; Hitoshi Aoyama

Background A causal association between cigarette smoking and periodontal disease has been established. The present study examined the association between smoking and tooth loss using national databases in Japan. Methods Records of the Survey of Dental Diseases and the National Nutrition Survey in 1999 were linked electronically using common identification. Records of 3,999 subjects aged older than 40 years were analyzed using logistic regression models, controlling for confounding factors, such as age, frequency of tooth brushing, body mass index, alcohol consumption, and intakes of vitamin C and E. Results Prevalence of tooth loss in terms of having less than 19 existing teeth was 37.3% overall. Smoking rates differed in males (45.6%) and females (7.8%). The prevalence of tooth loss in nonsmokers, former, and current smokers was 28.5%, 38.6%, and 36.9% in males, and 38.6%, 34.3% and 38.9% in females, respectively. Adjusted means of existing teeth controlling for confounders by smoking status were 21.5, 19.7 and 18.2 in males and 19.0, 19.2 and 16.4 in females, respectively. The association of tooth loss was non-significant in former smokers but significant in current smokers: adjusted odds ratios (95% confidence intervals) relative to nonsmokers in males and females were 1.29 (0.92-1.80) and 0.86 (0.46, 1.60) for former smokers and 2.22 (1.61-3.06) and 2.14 (1.45-3.15) for current smokers, respectively. A dose-response relationship between lifetime exposure and tooth loss was seen (P for trend <0.0001). Conclusion The findings of this cross-sectional study of a nationwide population of Japanese indicated an association between smoking and tooth loss.


BMC Public Health | 2007

Cigarette smoking and tooth loss experience among young adults: a national record linkage study

Miki Ojima; Takashi Hanioka; Keiko Tanaka; Hitoshi Aoyama

BackgroundVarious factors affect tooth loss in older age including cigarette smoking; however, evidence regarding the association between smoking and tooth loss during young adulthood is limited. The present study examined the association between cigarette smoking and tooth loss experience among adults aged 20–39 years using linked data from two national databases in Japan.MethodsTwo databases of the National Nutrition Survey (NNS) and the Survey of Dental Diseases (SDD), which were conducted in 1999, were obtained from the Ministry of Health, Labor and Welfare with permission for analytical use. In the NNS, participants received physical examinations and were interviewed regarding dietary intake and health practices including cigarette smoking, whereas in the SDD, participants were asked about their frequency of daily brushing, and received oral examinations by certified dentists. Among 6,805 records electronically linked via household identification code, 1314 records of individuals aged 20 to 39 years were analyzed. The prevalence of 1+ tooth loss was compared among non-, former, and current smokers. Multiple logistic regression models were constructed including confounders: frequency of tooth brushing, body mass index, alcohol consumption, and intake of vitamins C and E.ResultsSmoking rates differed greatly in men (53.3%) and women (15.5%). The overall prevalence of tooth loss was 31.4% (31.8% men and 31.1% women). Tooth loss occurred more frequently among current smokers (40.6%) than former (23.1%) and non-smokers (27.9%). Current smoking showed a significant association with 1+ tooth loss in men (adjusted OR = 2.21 [1.40–3.50], P = 0.0007) and women (1.70 [1.13–2.55], P = 0.0111). A significant positive exposure-related relationship between cigarette smoking status and tooth loss was observed (P for trend < 0.0001 and 0.0004 in men and women, respectively). Current smoking was also associated with the prevalence of decayed teeth (1.67 [1.28–2.20], P = 0.0002).ConclusionAn association between cigarette smoking and tooth loss was evident among young adults throughout Japan. Due to limitations of the available variables in the present databases, further studies including caries experience and its confounders should be conducted to examine whether smoking is a true risk of premature tooth loss in young adults.


Pediatrics | 2005

Association of Melanin Pigmentation in the Gingiva of Children With Parents Who Smoke

Takashi Hanioka; Keiko Tanaka; Miki Ojima; Kazuo Yuuki

Objective. The association between gingival pigmentation and active smoking has been established. This investigation is the first to address the relationship between gingival pigmentation in children and passive smoking. Methods. A case-control study was performed involving 59 nonsmoking children who were selected from patient records of a dental clinic in a rural town in Japan. The number of subjects was based on a power calculation. Two calibrated examiners independently observed labial gingiva via oral photographs. Results. An interview determined that 61% of children had at least 1 smoking parent. Gingival pigmentation was observed in 71% to 78% of children. Interexaminer agreement was satisfactory (κ = 0.73). Percentage of smoking parents was higher in children with gingival pigmentation (70–71%) than in those who lacked pigmentation (35%). Odds ratios of parental smoking adjusted by age and gender were 5.6 (95% confidence interval: 1.5–20.0) and 5.4 (1.4–21.2) for the 2 examiners. Conclusion. These findings suggest that excessive pigmentation in the gingiva of children is associated with passive smoking. The visible pigmentation effect in gingiva of children could be useful in terms of parental education.


Journal of Dental Research | 2010

Intensive Smoking-cessation Intervention in the Dental Setting

Takashi Hanioka; Miki Ojima; Hideo Tanaka; Mariko Naito; Nobuyuki Hamajima; R. Matsuse

Smoking exerts detrimental effects on dental treatment and oral health. Our goal was to evaluate effectiveness in terms of the abstinence rate in smoking-cessation intervention delivered by dental professionals. Individuals who were willing to quit smoking were randomly assigned to either an intervention or a non-intervention group. Intensive intervention was provided, consisting of 5 counseling sessions, including an additional nicotine replacement regimen. Reported abstinence was verified by the salivary cotinine level. Thirty-three persons in the intervention and 23 in the non-intervention group started the trial. On an intent-to-treat basis, 3-, 6- and 12-month continuous abstinence rates in the intervention group were 51.5%, 39.4%, and 36.4%, respectively, while the rates in the non-intervention group were consistent at 13.0%. Adjusted odds ratios (95% confidence interval) by logistic stepwise regression analyses were 7.1 (1.8, 28.5), 8.9 (1.7, 47.2), and 6.4 (1.3, 30.7), respectively. Intensive smoking-cessation intervention in the dental setting was therefore effective.


Paediatric and Perinatal Epidemiology | 2008

Dental caries in 3-year-old children and smoking status of parents.

Takashi Hanioka; Etsuko Nakamura; Miki Ojima; Keiko Tanaka; Hitoshi Aoyama

An association has been suggested between environmental tobacco smoke and oral disease. The present study examined the relationship between early childhood caries (ECC) and parental smoking, particularly paternal smoking, using records of 711 36-month-old children. The smoking status of parents as an independent variable was entered in the multivariable logistic regression model for caries experience as the dependent variable with confounders: sex, residential location, and possible risks of ECC such as order of birth, type of main drink, frequency of daily intake of sugar-containing snacks, daily toothbrushing by parents and use of fluoridated toothpaste. About 65% of children were caries free. Children whose parents did not smoke (CN), those in whom only the father smoked (CF), and those whose mother smoked regardless of the smoking status of the father (CM) comprised 33%, 33% and 34% respectively. The adjusted mean number [95% CI] of decayed teeth and caries experience prevalence for CN, CF and CM were 1.2 [0.8, 1.6], 1.6 [1.2, 2.0] and 2.1 [1.7, 2.5], and 25.6%, 35.3% and 45.7% respectively. The relationship between caries experience and parental smoking was significant on multivariable analysis. The adjusted OR [95% CI] of CF and CM relative to CN was 1.52 [1.01, 2.30] and 2.25 [1.51, 3.37] respectively. These results indicate the association of ECC with parental smoking, although the association with paternal smoking was weaker than with maternal smoking.


International Journal of Environmental Research and Public Health | 2011

Does secondhand smoke affect the development of dental caries in children? A systematic review.

Takashi Hanioka; Miki Ojima; Keiko Tanaka; Mito Yamamoto

This review evaluated evidence of the relationship between secondhand smoke (SHS) and dental caries in children in epidemiological studies. Relevant literature was searched and screened, and the methodological quality was assessed. The search yielded 42 citations. High-quality studies including one cohort format and 14 case-control format studies were selected. Early childhood caries was examined in 11 studies. The independent association of SHS was significant in 10 studies, and the strength was mostly weak to moderate. One study did not select SHS as a significant variable. Three studies reported decreases in the risk of previous exposure, and the association was not significant. Dose-response relationships were evident in five studies. Permanent teeth were examined in seven studies. Five studies reported significant associations, which were mostly weak. The risk of previous exposure remained similar to that of current exposure, and a dose-response relationship was not evident in one study. The overall evidence for the causal association in early childhood caries is possible regarding epidemiological studies, and the evidence of permanent teeth and the effect of maternal smoking during pregnancy were insufficient. The results warrant further studies of deciduous teeth using a cohort format and basic studies regarding the underlying mechanism.

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Takashi Hanioka

University of Texas Health Science Center at Tyler

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