Nobuyoshi Ozawa

National Center for Geriatrics and Gerontology, Ōfu, Aichi, Japan

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Publications (13)11.75 Total impact

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    ABSTRACT: The oral management of dementia patients is critical to prevent aspiration pneumonia and maintain patients' quality of life. However, the oral health status of these patients has not been adequately elucidated thus far, and it is not well understood how oral care is managed for mild dementia patients. To provide effective oral management for mild dementia patients, we investigated their oral health status and how their oral care was managed. We enrolled 10 outpatients aged 66 to 85 years old who regularly visited our neurology clinic. All of the patients had mild dementia. We conducted 2 questionnaire studies regarding oral hygiene and dentures and performed an oral examination to evaluate the changes in oral hygiene status over time. The questionnaire was designed to explore the understanding of oral hygiene methods. Oral care instructions were given to the patients and their caregivers. Three surveys of 2 questionnaires each were performed. The survey was conducted at the initial visit, and 3 months and 6 months later. Although oral care instructions were given to the patients and their caregivers, neither their plaque index nor gingival index showed major improvement over time. Based on the results of these questionnaires, patient awareness of oral hygiene did not change over time. It is difficult for patients with mild dementia to perform oral care by themselves. It is important to make oral hygiene habits second nature in middle-aged patients, to introduce oral management to be performed by the caregivers and to promote early dental intervention to improve and maintain oral hygiene status in mild dementia patients.
    Nippon Ronen Igakkai Zasshi Japanese Journal of Geriatrics 01/2012; 49(1):90-8. DOI:10.3143/geriatrics.49.90
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    ABSTRACT: Current diagnostic imaging modalities for resin-based composites (RBC) do not possess sufficient resolution and cross-sectional tomographic imaging to detect defects of RBC restorations in real-time. The purpose of this in vivo study was to investigate swept-source optical coherence tomography (SS-OCT) as a new tool to evaluate defects of RBC restorations. We evaluated for the failure of RBC restorations in 52 patients (11 male, 41 female) at the Division of Oral and Dental Surgery, National Centre for Geriatrics and Gerontology, Japan. SS-OCT images of the 132 RBC restorations were obtained in order to investigate their marginal adaptation, porosity and internal integrity. Rates of defective restorations in terms of marginal adaptation, large porosity and gap formation were 65.2 percent, 27.3 percent, and 15.2 percent, respectively. Only 18.9 percent of the RBC restorations had no defects. SS-OCT has the potential to provide higher-resolution information related to the structure of RBC restorations currently unavailable with any diagnostic or imaging method.
    Journal of dentistry 05/2011; 39(8):543-8. DOI:10.1016/j.jdent.2011.05.005 · 3.20 Impact Factor
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    ABSTRACT: The porosity of resin artificial teeth continues to be one of the undesirable characteristics of resin materials. It is commonly accepted that porosity of the denture not only often leads to denture fractures and stains, but also may function as a reservoir of potential pathogens. Objectives: The aim of this study was to present the first OCT (Optical Coherence Tomography) image of commercial resin artificial teeth using a new advanced-type OCT scanner, and to discuss the application of our new OCT system for nondestructive inspection of resin artificial teeth. Methods: We jointly developed a new swept-source optical coherence tomography (SS-OCT) system with Santec Corporation. This SS-OCT system (Santec OCT-2000) was used for cross-sectional imaging of resin artificial teeth as a nondestructive inspection method. 5 commercial brands of composite resin artificial teeth and 5 commercial brands of acrylic resin artificial teeth were selected for this study. OCT images were evaluated by using image analysis software of Lab ViewR. Results: OCT provided clear images of all these materials. Internal structures, not detected by visual inspection, can be observed using this OCT system. The OCT images revealed the difference in the internal structures among the products. Composite resin artificial teeth's OCT images showed a homogeneous signal-rich layer with a few scattered signal-poor areas in enamel layers. In one of these images, any air bubble formation in the composite layer were observed. In OCT images of acrylic resin artificial teeth, roundish signal-poor areas, suggesting mainly polymers and sparse voids, sharply demarcated by a surrounding signal-rich layer were observed. Conclusion: This study demonstrated for the first time that OCT can detect nonvisible internal structures in resin artificial teeth. OCT may, therefore, be an appropriate method for non destructive detection of interior defects in dentures.
    IADR General Session 2011; 03/2011
  • Y. SUMI, J. TAGAMI, N. OZAWA
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    ABSTRACT: Objectives: The porosity of denture base resins continues to be one of the undesirable characteristics of acrylic resins. It is commonly accepted that porosity of the denture not only often leads to denture fractures, but also may function as a reservoir of potential pathogens. The purpose of this study was to present the first OCT images of finished dentures using a new advanced-type OCT scanner we have developed, and to discuss the application of our new OCT system for non-destructive inspection of dentures. Methods: The National Center for Geriatrics and Gerontology has jointly developed a new swept-source optical coherence tomography (SS-OCT) system (Santec OCT-2000) together with Santec Corporation in Aichi Japan in an official collaborative relationship between industry and government. Ten newly fabricated full dentures of outpatient of the National Center for Geriatrics and Gerontology in Japan were selected for this study. Two types of denture base resins were used for inspection by OCT, which provided clear images of all the dentures examined. The ethical regulations of the National Center for Geriatrics and Gerontology were strictly followed. The study was approved by the Institutional Review Board of the National Center for Geriatrics and Gerontology in Japan. Results: Internal structures, not visually detectable, inspection, can be observed using this OCT system. It is concluded that OCT can detect nonvisible internal structures in dentures, a finding not reported to date. Conclusion: OCT may, therefore, be an appropriate method for detecting interior defects in dentures nondestructively.
    IADR General Session 2011; 03/2011
  • N. OZAWA, J. TAGAMI, Y. SUMI
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    ABSTRACT: Objectives: Early detection methods have great potential for improving the quality of life and survival rates for oral cancer patients. Optical coherence tomography (OCT) has emerged as a high-resolution noninvasive clinical imaging application. The purpose of this study was to show OCT images of oral squamous cell carcinoma (OSCC) obtained using a swept-source OCT system. Methods: The National Center for Geriatrics and Gerontology (NCGG) in Japan has jointly developed a new swept-source optical coherence tomography (SS-OCT) system (Santec OCT-2000) together with Santec Corporation Japan. OSCC OCT imaging was carried out using our new SS-OCT system for three patients using a hand-held in vivo OCT scanning probe. OCT imaging was carried out preoperatively, with the patient's written informed consent. The ethical regulations of the NCGG were strictly followed. The study was approved by the Institutional Review Board of the NCGG in Japan. Results: The resulting in-vivo ultrahigh-resolution OCT images of OSCC on the tongue revealed differential lesions with corresponding tumor-cell lysis. Vertical and horizontal OCT images were capable of providing simultaneous and noninvasive structural information with high resolution. In addition, one-dimensional intensity signal waveform graphs revealed the different tendencies. Conclusion: Future advances in OCT techniques promise to allow more definite evaluation of oral disease and further contribute to the screening, diagnosis and treatment of oral cancer.
    IADR General Session 2011; 03/2011
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    ABSTRACT: The purpose of this study was to ascertain the current statuses and problems of dental home care patients by surveying the oral care status and needs of patients in the home medical care support ward at the National Center for Geriatrics and Gerontology. Patients that required continuous oral management even after discharge from the hospital were referred to local dental clinics to receive home dental care. We investigated the suitability and problems associated with such care, and identified the dental care needs of home patients and the status of local care coordination, including those in hospitals. The subjects were 82 patients. We ascertained their general condition and oral status, and also investigated the problems associated with patients judged to need specialized oral care by a dentist during oral treatment. Patients who required continuous specialized oral care after discharge from hospital were referred to dental clinics that could provide regular care, and the problems at the time of referral were identified. Dry mouth was reported by many patients. A large number of patients also needed specialized dental treatment such as the removal of dental calculus or tooth extraction. Problems were seen in oral function, with 38 of the patients (46%) unable to gargle and 23 (28%) unable to hold their mouths open. About half of the patients also had dementia, and communication with these patients was difficult. Of the 43 patients who were judged to need continuing oral care after discharge from hospital, their referral to a dental clinic for regular care was successful for 22 (51%) patients and unsuccessful for 21 (49%) patients. The reasons for unsuccessful referrals included the fact that the family, patient, nurse, or caregiver did not understand the need for specialized oral care. The present results suggest the need for specialized oral treatment in home medical care. These findings also suggest that coordinating seamless dental care among primary physicians, intermediates, and transferring care after hospital discharge to regular dentists is difficult.
    Nippon Ronen Igakkai Zasshi Japanese Journal of Geriatrics 01/2011; 48(4):391-6. DOI:10.3143/geriatrics.48.391
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    ABSTRACT: The porosity of denture base resins continues to be one of the undesirable characteristics of acrylic resins. It is commonly accepted that porosity of the denture not only often leads to denture fractures, but also may function as a reservoir of potential pathogens. The purpose of this study was to present the first OCT images of finished dentures using a new advanced-type OCT scanner we have developed, and to discuss the application of our new OCT system for nondestructive inspection of dentures. Ten newly fabricated full dentures of outpatient of the National Center for Geriatrics and Gerontology in Japan were selected for this study. Two types of denture base resins were used for inspection by OCT, which provided clear images of all the dentures examined. Internal structures, not visually detectable, inspection, can be observed using this OCT system. It is concluded that OCT can detect nonvisible internal structures in dentures, a finding not reported to date. OCT may, therefore, be an appropriate method for detecting interior defects in dentures nondestructively.
    Archives of gerontology and geriatrics 12/2010; 53(2):237-41. DOI:10.1016/j.archger.2010.11.022 · 1.36 Impact Factor
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    ABSTRACT: In this laboratory study, we examined the use of a swept-source optical coherence tomography (SS-OCT) as a diagnostic tool for occlusal caries. One-hundred and eleven investigation sites of occlusal fissures were selected from 62 extracted teeth and examined visually using conventional dental equipment without any magnification. SS-OCT observations were carried out on the same locations as where the conventional examination had been performed. The teeth were then sectioned using a diamond saw and directly viewed under a confocal laser scanning microscope (CLSM). Presence and extent of caries was scored in each observation and the obtained results from SS-OCT and conventional visual inspection were compared with the CLSM. The reproducibility and indices of sensitivity and specificity of SS-OCT were calculated and compared with those of the visual inspection. The results were statistically analyzed using receiver operating characteristic (ROC) curve and Spearman rank correlation test. SS-OCT could clearly detect the presence of enamel demineralization lesion in a tomography image synthesized based on the backscatter signal (sensitivity=0.98). Although the sensitivity for dentine caries of SS-OCT was over that of the visual inspection, the detection level was decreased to 0.60. When the methods were compared to the CLSM, the diagnostic accuracy of SS-OCT was better than that of the conventional visual inspection (Az values of visual inspection and SS-OCT, 0.74 versus 0.86 for enamel demineralization, 0.68 versus 0.80 for dentine caries; Spearman's correlation coefficients to CLSM; visual inspection: 0.665, SS-OCT: 0.824). The carious demineralization, especially in enamel, can be clearly discriminated as a highlighted area due to scattering of light matches the location of demineralized area at the base of the fissure and the results correlated well with the CLSM.
    Journal of dentistry 08/2010; 38(8):655-65. DOI:10.1016/j.jdent.2010.05.004 · 3.20 Impact Factor
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    ABSTRACT: Objectives: Detection of pit and fissure caries by current methods is not highly sensitive. Optical coherence tomography (OCT) is a promising diagnostic method for creating cross-sectional imaging of internal biological structures by measuring echoes of backscattered light. In this ex vivo study, we examined a swept-source OCT (SS-OCT) as a diagnostic tool for occlusal caries. Methods: 117 investigation sites of occlusal fissures were selected from 62 extracted teeth and inspected visually using conventional dental equipment without any magnification. SS-OCT observation was also carried out on the same location as where the conventional inspection had been performed. The teeth were then sectioned using a diamond saw and directly viewed under a confocal laser scanning microscope (CLSM). Presence and extent of caries was scored in each observation and the obtained results from SS-OCT and conventional visual inspection were compared with the CLSM. Results: SS-OCT could clearly detect the presence of enamel demineralization lesion in a tomography image synthesized based on the backscattering signal (sensitivity = 0.98). Although the sensitivity for dentin caries of SS-OCT was over that of the visual inspection, the detection level was decreased down to 0.73. When the methods were compared to the CLSM, the diagnostic accuracy of SS-OCT was better than that of the conventional visual inspection (efficiency of visual inspection and SS-OCT, 0.56 versus 0.78; Spearman's correlation coefficient to CLSM, visual inspection: 0.772, SS-OCT: 0.906). Conclusions: The carious demineralization, especially in enamel, can be clearly discriminated as the highlighting due to scattering of light matches the location of demineralized area at the base of the fissure and the results well correlated with the CLSM. Supported by Grants-in-Aid for Scientific Research #21592415 and Research Grant for Longevity Sciences #21A-8 MHLW
    IADR General Session 2010; 07/2010
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    ABSTRACT: The purpose of this study was to evaluate the effect of continuous oral care on the nutritional status of older people who require care using a 1-year randomized, controlled study. Fifty-three residents of a nursing home in Japan participated in this study. Subjects were randomly divided into two groups, an oral care intervention group and control group. The subjects in the oral care intervention group received professional oral care from a dentist three times a week over the course of 1 year. Body weight, body mass index (BMI), serum albumin, and high-density lipoprotein cholesterol (HDL-C) were measured as objective indicators of nutritional status at baseline and after 1 year, and compared between the groups. In the oral care group, no significant decline was seen in all indicators from the start to the end of the intervention, but in the control group there was a statistically significant decline in all indicators at the end of the year. These results suggest that the intervention of oral care alone can serve to maintain the nutritional status of older people who require care. Implementation of continuous oral care is an important task from the viewpoint of maintaining nutritional status in older people.
    Archives of gerontology and geriatrics 11/2009; 51(2):125-8. DOI:10.1016/j.archger.2009.09.038 · 1.36 Impact Factor
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    ABSTRACT: Optical coherence tomography (OCT) has emerged as a high-resolution noninvasive clinical imaging application. The purpose of this study was to show OCT images of human labial glands obtained using a swept-source (SS) OCT system. Labial gland OCT imaging was carried out using our new SS-OCT system for 5 healthy volunteers using a hand-held in vivo OCT scanning probe. The labial tissue was scanned in a superior to inferior direction in 2 and 3 dimensions. The resulting 2- and 3-dimensional ultrahigh-resolution images of in vivo OCT human labial minor salivary glands revealed the epithelium, connective tissue, lobes, and duct. OCT was capable of providing simultaneous and noninvasive structural information with high resolution. This clinical imaging modality promises to have clinical impact in the diagnosis of such conditions as Sjögren syndrome and xerostomia.
    Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 10/2009; 108(3):425-9. DOI:10.1016/j.tripleo.2009.05.035 · 1.50 Impact Factor
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    ABSTRACT: Optical coherence tomography (OCT) is a new method of biomedical imaging that can generate high-resolution, cross-sectional images of microstructures. The purpose of this study was to present the first OCT images of oral vascular anomalies using a new advanced OCT scanner that we have developed, and to discuss the application of our system for oral soft tissues. Knowledge of the size and area of the vascular structures can be useful for the diagnosis and choice of the best treatment. Before excision, oral vascular malformations were assessed by OCT in vivo. Histopathological sections were taken and compared with the OCT images to make clinicopathological correlations. OCT provided clear images of all the vascular lesions examined. Oval to roundish, signal-poor areas sharply demarcated by a surrounding signal-rich layer correlated well with the histopathological diagnosis. OCT images provide information about subsurface structure non-invasively that is otherwise obtainable only by examination of a biopsy specimen. The analysis of oral vascular lesions by OCT provides new insights into non-invasive diagnosis and can be helpful in the selection of the most appropriate treatment.
    British Journal of Oral and Maxillofacial Surgery 05/2009; 47(8):622-6. DOI:10.1016/j.bjoms.2009.03.012 · 1.13 Impact Factor
  • Nippon Koku Geka Gakkai zasshi 01/2009; 55(5):255-259. DOI:10.5794/jjoms.55.255