Yuichi Kitasako

Tokyo Medical and Dental University, Edo, Tōkyō, Japan

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Publications (64)100.65 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Objectives The objectives of this study were to clarify the prevalence of dental erosion in the deciduous dentition of child patients, and to identify dietary habits and other factors related to dental erosion. Methods A total of 116 weaned child patients (67 boys, 49 girls) aged 2–6 years who attended the outpatient pediatric dental clinic of a university hospital for treatment or a periodic checkup were included in the study. A questionnaire survey of the patients' dietary habits and a clinical examination were performed. Dentition was divided into four areas, and responses to erosion-related questions were evaluated for each area using multiple logistic regression analysis. Results The prevalence of subjects with erosion, including pre-erosion lesions without tooth surface defects, was 86%; the prevalence of advanced erosion accompanied by tooth surface defects was 34%. Some food- and drink-related items were found to be significantly associated with erosion of the maxillary anterior teeth but not the mandibular teeth. Medication, use of fluoride, and past dental or medical history did not have any significant effect on erosion in any of the four areas. Conclusions The occurrence of dental erosion in deciduous dentition and factors related to its appearance were clarified for each area. An epidemiological survey is required to further reveal the state of deciduous dental erosion in Japanese children and to investigate the necessity of, and, if necessary, establish relevant guidelines for the prevention of dental erosion.
    Pediatric Dental Journal. 08/2014;
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    ABSTRACT: Optical coherence tomography (OCT) is a potential clinical tool for enamel lesion monitoring. Swept-source OCT findings were compared with cross-sectional nanohardness findings of enamel. Subsurface bovine enamel lesions in three groups were subjected to (1) deionized water (control), (2) phosphoryl oligosaccharide of calcium (POs-Ca) or (3) POs-Ca with 1 ppm fluoride for 14 days. B-scans images were obtained at 1310-nm center wavelength on sound, demineralized and remineralized areas after 4, 7, and 14 days. The specimens were processed for cross-sectional nanoindentation. Reflectivity from enamel that had increased with demineralization decreased with remineralization. An OCT attenuation coefficient parameter (μt), derived based on the Beer-Lambert law as a function of backscatter signal slope, showed a strong linear regression with integrated nanohardness of all regions (p<0.001, r=-0.97). Sound enamel showed the smallest, while demineralized enamel showed the highest μt. In group three, μt was significantly lower at four days than baseline, but remained constant afterwards. In group two, the changes were rather gradual. There was no significant difference between groups two and three at 14 days in nanohardness or μt POs-Ca with fluoride-enhanced nanohardness of the superficial zone. OCT signal attenuation demonstrated a capability for monitoring changes of enamel lesions during remineralization.
    Journal of Biomedical Optics 04/2013; 18(4):46006. · 2.75 Impact Factor
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    ABSTRACT: Early detection, monitoring and remineralization repair of enamel lesions are top research priorities in the modern dentistry focusing on minimal intervention concept for caries management. We investigate the use of swept-source optical coherence tomography system (SS-OCT) without polarization-sensing at 1319 nm wavelength developed for clinical dentistry (Dental OCT System Prototype 2, Panasonic Healthcare Co., Ltd., Japan) in quantitative assessment of artificial enamel lesions and their remineralization. Bovine enamel blocks were subjected to demineralization to create subsurface lesions approximately 130 μm in depth over 2 weeks, and subjected to remineralization in solution containing bioavailable calcium and 1ppm fluoride at pH 6.5 for 2 weeks. Cross-sectional images of sound, demineralized and remineralized specimens were captured under hydrated conditions by the OCT. Finally, the specimens were cut into sections for nanoindentation to measure hardness through the lesion under 2mN load. Reflectivity had increased with demineralization. OCT images of lesions showed a boundary closely suggesting the lesion depth that gradually progressed with demineralization time. After remineralization, the boundary depth gradually decreased and nanoindentation showed over 60% average hardness recovery rate. A significant negative correlation was found between the slope power-law regression as a measure of attenuation and overall nanohardness for a range of data covering sound, demineralized and remineralized areas. In conclusion, OCT could provide clear images of early enamel lesion extent and signal attenuation could indicate its severity and recovery. Clinical data of natural lesions obtained using Dental OCT and analyzed by this approach will also be presented. Study supported by GCOE IRCMSTBD and NCGG.
    Proc. SPIE. 8566, Lasers in Dentistry XIX 856602; 03/2013
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    ABSTRACT: This study aimed to evaluate effectiveness of Phosphoryl-Oligosaccharides of Calcium (POs-Ca) added to apple juice on enamel erosion. Five juices were prepared by adding 0%, 0.5%, 1%, 1.5% or 2% POs-Ca to commercial apple juice, and subjected to Visual Analogue Scale (VAS) taste evaluation and pH and calcium/inorganic-phosphates analyses. To evaluate erosion, polished bovine enamel blocks were immersed in each juice for 5 or 60 min (n=20). Enamel surface loss (SL) and roughness (Ra) were also analyzed. VAS indicated acceptable taste for juices containing up to 1% POs-Ca. POs-Ca addition resulted in increased pH (3.61-3.88), calcium (0.95-25.10 mM), and inorganic-phosphate (1.77-20.44 mM). After 5 min, 0% juice resulted in significant erosion (p<0.05). However even after 60 min, no significant increase was found in Ra and SL compared to water (control) for 1.5-2% juices (p>0.05). Addition of 1-1.5% POs-Ca could significantly reduce enamel erosion by apple juice maintaining an acceptable taste.
    Dental Materials Journal 01/2013; 32(2):212-8. · 0.81 Impact Factor
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    ABSTRACT: A low pH environment is created by cariogenic bacteria. This study was aimed to measure pH of carious lesions intraorally using a micro-pH sensor, and assess predominant acid-producing cariogens by qPCR to differentiate caries activities. 103 dentine lesions classified as active or arrested caries based on the clinical and radiological examinations were collected from patients after intraoral measurement of the lesion surface pH using a micro-pH sensor. Quantitative detection of genomic DNA copies of target cariogenic bacteria (mutans streptococci and Lactobacillus spp.) in each lesion was performed using real-time PCR. Correlation between the pH ranges and the number of bacterial species was examined by Spearman test. 50 samples were diagnosed as active and 53 as arrested lesions. Statistically significant difference was observed on average surface pH value between active and arrested lesions (p<0.05). Prevalence of Lactobacillus spp. was higher in active lesions than in arrested lesions (76% vs. 58% of samples, respectively). When the carious lesions were categorised into four different pH ranges (up to 5.5, from 5.6 to 5.8, from 5.9 to 6.1 and 6.2 or above), increased prevalence of Lactobacillus spp. was observed with decrease of pH levels. A significant negative relationship was found between pH value and number of Lactobacillus spp. (r=-0.209, p<0.05) but no such correlation was found for mutans streptococci. Intraoral pH measurement might be clinically useful to determine acidity of the local environment of carious lesions as one aspect of the caries activity assessment. The population of certain bacteria may indicate activity of carious lesions. Intraoral pH measurement of the carious lesions using a micro-pH sensor may be a clinically feasible method for assessment of lesion acidity.
    Journal of dentistry 03/2012; 40(3):222-8. · 3.20 Impact Factor
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    Y Kitasako, A Sadr, H Hamba, M Ikeda, J Tagami
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    ABSTRACT: The aim of this study was to assess the effect of chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and a low concentration of fluoride (F) on the hardness of enamel subsurface lesions, utilizing a double-blind, randomized, and controlled in situ model. Fifteen individuals wore removable lingual appliances with 3 bovine-enamel insets containing subsurface demineralized lesions. Three times a day for 14 days, they chewed one of the 3 chewing gums (placebo, POs-Ca, POs-Ca+F). After the treatment period, cross-sectional mineral content, nanoindentation hardness, and fluoride ion mapping by time-of-flight secondary ion mass spectrometry (TOF-SIMS) were evaluated. Although there were no statistical differences in overall mineral content and hardness recovery rates between POs-Ca and POs-Ca+F subsurface lesions (p > 0.05), nanoindentation at 1-μm distance increments from the surface showed statistical differences in hardness recovery rate between POs-Ca and POs-Ca+F in the superficial 20-μm region (p < 0.05). Fluoride mapping revealed distribution of the ion up to 20 μm from the surface in the POs-Ca+F group. Nanoindentation and TOF-SIMS results highlighted the benefits of bioavailability of fluoride ion on reinforcement of the superficial zone of subsurface lesions in situ (NCT01377493).
    Journal of dental research 02/2012; 91(4):370-5. · 3.46 Impact Factor
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    ABSTRACT: Manufacturers are adding fluoride (F) to calcium-containing chewing gums to further promote enamel remineralization. The aim of this study was to assess the effect of a chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and fluoride on remineralization of enamel subsurface lesions, in a double-blind, randomized controlled in situ trial. Thirty-six volunteer subjects wore removable buccal appliances with three different insets of bovine enamel with subsurface demineralized lesions. For 14 days the subjects chewed one of the three chewing gums (placebo, POs-Ca, POs-Ca+F), three times a day. After each treatment period, the insets were removed from the appliance, embedded, sectioned, polished and then subjected to laboratory tests; mineral level was determined by transverse microradiography (TMR; n=36), and hydroxyapatite (HAp) crystallites were assessed by synchrotron radiation wide-angle X-ray diffraction (WAXRD; n=13). Data were analysed by t-test or Wilcoxon rank-sum test with Bonferroni corrections at 0.05 significance level. Chewing POs-Ca and POs-Ca+F gums resulted in 21.9±10.6 and 26.3±9.4 (mean±SD) percentage mineral recovery, which was significantly higher than that of placebo gum (15.0±11.4) (p<0.05). Chewing POs-Ca+F gum resulted in 24.9±5.4 (mean±SD) percentage HAp crystallites recovery, which was significantly higher compared to POs-Ca (16.0±4.1%) or placebo (11.1±4.8%) gums (p<0.05). Addition of POs-Ca to the chewing gum resulted in significant remineralization of enamel subsurface lesions. Although POs-Ca+F gum was not superior in TMR recovery rate when compared with POs-Ca gum, WAXRD results highlighted the importance of fluoride ion bioavailability in the formation of HAp crystallites in enamel subsurface lesions in situ (NCT01377493).
    Journal of dentistry 08/2011; 39(11):771-9. · 3.20 Impact Factor
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    ABSTRACT: This study aimed to assess dentin bond durability of 4-META/MMA-TBB resin cement over ten years, by evaluating the tensile bond strength, and SEM and TEM observations. Tensile bond strength of Super Bond C&B (SB) to bovine dentin was evaluated at 1 day and after 10 years. The mode of failure after debonding was observed by SEM. Interfacial ultrastructure and nanoleakage was observed by TEM at the baseline and after 10 y. The tensile bond strength significantly dropped after 10 y. The failure pattern shifted from cohesive failure in resin towards adhesive failure or cohesive failure in dentin. TEM observation revealed degradation of both resin and collagen networks within the hybrid layer and nanoleakage at the base of the hybrid layer after 10 y. The bond strength of SB to dentin significantly decreased, and the hybrid layer degraded, while the overlying hydrophobic resin layer showed little disintegration over 10 y.
    Dental Materials Journal 07/2011; 30(4):438-47. · 0.81 Impact Factor
  • Mie Fujii, Yuichi Kitasako, Alireza Sadr, Junji Tagami
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    ABSTRACT: This study aimed to evaluate enamel surface roughness (Ra) and pH before and after erosion by soft drinks. Enamel was exposed to a soft drink (cola, orange juice or green tea) for 1, 5 or 60 min; Ra was measured using contact-stylus surface profilometry (SSP) and non-contact focus variation 3D microscope (FVM). Surface pH was measured using a micro pH sensor. Data were analyzed at significance level of alpha=0.05. There was a significant correlation in Ra between SSP and FVM. FVM images showed no changes in the surface morphology after various periods of exposure to green tea. Unlike cola and orange juice, exposure to green tea did not significantly affect Ra or pH. A significant correlation was observed between surface pH and Ra change after exposure to the drinks. Optical surface analysis and micro pH sensor may be useful tools for non-damaging, quantitative assessment of soft drinks erosion on enamel.
    Dental Materials Journal 06/2011; 30(3):404-10. · 0.81 Impact Factor
  • H. MITA, Y. KITASAKO, T. TAKAGAKI, J. TAGAMI
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    ABSTRACT: Objectives: The aims of this study were development and evaluation of a low erosive apple juice with Phosphoryl-Oligosaccharides of Calcium (POs-Ca). POs-Ca is produced by enzymatic digestion of potato starch and has been compounded into a chewing gum (POs-Ca, Ezaki Glico Co., Ltd., Osaka, Japan). Methods: 5 juices were prepared by adding 0% (control), 0.5%, 1%, 1.5% or 2% POs-Ca to apple juice. Each juice was evaluated for taste, pH value, chemical composition with respect to calcium/inorganic-phosphates, and effectiveness against enamel erosion. Drink taste was rated using Visual Analogue Scale (VAS) by a taste panel of 30 volunteers that provided informed consent. To evaluate erosion, polished bovine enamel blocks were immersed in each juice for 5min or 60min (n=5). Then, surface characteristics/morphological changes and surface roughness (Ra) of enamel were evaluated by focus variation 3D scanning microscopy (InfiniteFocus1 G4, Alicona Imaging, Grambach/Graz, Austria). Ra was analyzed by two-way ANOVA and t-test with Bonferroni correction. Results: VAS indicated acceptable taste for juices containing up to 1% POs-Ca. The drinks showed pH of 3.5-3.8, calcium concentration of 1.0-25.1mM, and inorganic-phosphate concentration of 1.8-20.4mM. Erosive challenges with 1%-2% POs-Ca juices for 5min, or with 1.5%-2% POs-Ca juices for 60min resulted in only slight changes in enamel surface, so that the prismatic appearance of enamel was visible with no damage. After 5min, there were statistical differences in Ra between 0% POs-Ca juice (35.53.6nm) and 1%, 1.5% and 2% POs-Ca juices (13.44.1nm, 9.12.0nm and 8.81.9nm, respectively) (p<0.05). Likewise, after 60min, statistical differences existed between 0% POs-Ca juice (78.717.9nm) and 1%, 1.5% and 2% POs-Ca juices (27.66.0nm, 19.83.1nm and 15.42.3nm, respectively) (p<0.05). Conclusions: Addition of 1% to 1.5% POs-Ca to apple juice could significantly reduce enamel erosion resulting from immersion in the drink, while maintaining an acceptable taste. Supported by GCOE, IRCMSTBD at TMDU.
    IADR General Session 2011; 03/2011
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    F Hayati, A Okada, Y Kitasako, J Tagami, K Matin
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    ABSTRACT: The aim of this study was to establish a new in vitro model for biofilm induced secondary caries studies using an oral biofilm reactor. An approximately 2 × 3 × 2 mm(3) sized dentino-enamel Class I cavity was prepared in the middle of a square-shaped specimen from the mid-labial portion of bovine incisors. The cavities were partially filled with either Clearfil AP-X with SE-Bond or Clearfil AP-X without any bond. Artificial biofilms were then formed on the resin composite filled surfaces using three species of oral bacteria in an oral biofilm reactor for 20 hours followed by 7- or 30-day incubation periods. The lesions were clearly visible on fluorescence microscopy and by scanning electron microscopy in the enamel at the interface of resin restorations in all samples. The data from image analysis showed that the lesion size was largest in the No-bond samples with statistically significant differences (p < 0.05). Demineralization along the cavity wall extended deeper in No-bond compared to SE-Bond samples and penetration was significantly deeper in No-bond 30-day samples. A primary artificial secondary caries model was established using biofilms for in vitro studies and the significance of using a bonding system could also be verified.
    Australian Dental Journal 03/2011; 56(1):40-7. · 1.37 Impact Factor
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    ABSTRACT: The aims of this study were to clarify which steps in approximal restorative procedure were difficult for the final-year undergraduate students at Tokyo Medical and Dental University, and to examine the relationship between perception of difficulty and clinical experience. At mid-term of the clinical education experience, a self-questionnaire was performed by final-year undergraduate students to clarify the difficulty of restorative procedures at the time. There were statistically significant differences in the number of clinical cases experienced at the time between students who designated the matrix application, shade selection and finishing as the easy steps and those who considered them as the difficult ones (Fisher exact test with Bonferroni correction, p < 0.05). There was a significant difference in the total number of procedures designated as difficult between students who had treated above 15 cases and those who had fewer than 15 cases (Wilcoxon rank-sum test, p< 0.05). In the final-year clinical education for operative dentistry, students might need to treat over 15 cases to gain confidence in performing approximal composite restorations independently.
    Journal of medical and dental sciences 01/2011; 58(1):1-5.
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    ABSTRACT: Objectives: Although 4-META/MMA-TBB resin cement (Super Bond C&B, Sun Medical Co., Moriyama, Japan) has not changed in composition and has widely used in clinical practice for more than 10 y, there is no report of the laboratory bond durability and morphological degradation of hybrid layer over a long period of time. The purpose of this study was to evaluate dentin bond durability of a Super Bond C&B (SB) to extracted bovine dentin over 10 y. After the tensile bond test, the degradation of the bonded interface between resin cement and dentin was also evaluated using SEM and TEM. Methods: Ten bovine dentin specimens were tested for tensile bond strengths with SB at 1 d and 10 y. The mean bond strengths were compared statistically with the students t-test (p<0.05). The mode of failure after debonding was observed by SEM. The debonded specimen having only cohesive failure within the resin cement and partial adhesive failure was also used for TEM observation of the interfacial ultrastructure of the bond durability after 10 y. Results: The specimen stored in water for 10 y was significantly lower than 1 d in bond strength (p<0.01). At 1 d, 56 % of failures exhibited that cohesive failure within the resin cement only and partial adhesive failure, while, 69 % of the 10 y results exhibited that adhesive failure or cohesive failure in dentin. TEM observation revealed fracture occurred between SB and the hybrid layer or within the hybrid layer at 10 y, while failure only occurred within SB at 1 d. Conclusions: The bond strength of SB to dentin significantly decreased after 10 y, and the failure patterns of SB showed a marked change over 10 y. This study was supported by the GCOE Program at TMDU.
    IADR General Session 2010; 07/2010
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    ABSTRACT: Means of objectively assessing white spot enamel lesions (WSEL) are critical for determining their potential activity and monitoring the success of preventive treatments. The aim of this study was to determine whether surface pH measurements of WSEL changed during a preventive course of care designed to remineralize the lesions. Eight healthy subjects (1 male and 7 females) with at least one WSEL were recruited (19-64 years). Each subject was placed on a preventive treatment program including the daily application of a CPP-ACP paste (MI paste, GC Corp., Japan) with custom fitted trays for more than 6 months. The surface pH values of sound enamel and WSEL were monitored for up to 2 years using a micro-pH sensor. The visual appearance of the WSEL was monitored via digital photography, and images were analyzed qualitatively on a 5-point scale to assess the success of the remineralization preventive program. The relationship between the qualitative assessment of WSEL appearance and the WSEL pH was investigated using a Spearman's rho non-parametric correlation. The surface pH of the WSEL was different to that of the sound enamel surrounding it in all patients at all times. All lesions showed visual improvement as the treatment period progressed. The pH of the WSEL increased towards that of sound enamel over the course of treatment significantly correlating with the visual improvement of the lesion (rho=0.63, p<0.0001). The clinical assessment of WSEL surface pH changes with time may have utility as an additional objective measure for the assessment of WSEL activity.
    Journal of dentistry 07/2010; 38(7):584-90. · 3.20 Impact Factor
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    ABSTRACT: To evaluate the pretreatment effect of mild acidic HOCl solution on the microtensile bond strength (muTBS) of a two-step self-etch adhesive to dentin and the alteration of dentin surface pH. Thirty-nine flat ground coronal dentin specimens were divided into one control group and 12 experimental groups, which were treated with 6% NaOCl or 50, 100 and 200ppm HOCl (Comfosy) solutions for 5, 15 and 30s. After rinsing with running water for 30s, all the dentin surfaces were bonded with Clearfil SE Bond according to the manufacturer's instructions. After 24h water storage, the bonded specimens were sectioned and trimmed to an hourglass shape with a cross-sectional area of approximately 1.0mm(2) and then subjected to the muTBS test. Thirty-six mid-coronal dentin discs were used for surface pH measurement. Dentin surface pH with or without pretreatment was examined using a pH-imaging microscope (SCHEM-100). The muTBS data were analyzed by one-way ANOVA (Dunnett's T3) and the surface pH data were analyzed by non-parametric statistics (Mann-Whitney U-test). Pretreatment with Comfosy at concentrations of 50, 100 and 200 ppm did not significantly affect muTBS regardless of the application time compared with the control group, however the 100 and 200ppm Comfosy groups showed significantly lower surface pH values. For the NaOCl pretreatment groups, a longer application time significantly decreased the muTBS and increased the surface pH values compared to the control group. The 50ppm Comfosy pretreatments for 5, 15 and 30s did not affect the muTBS of the two-step self-etch adhesive to dentin and dentin surface pH.
    Journal of dentistry 11/2009; 38(3):261-8. · 3.20 Impact Factor
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    ABSTRACT: The aim of this study was to adapt a quantitative test for stimulated saliva, known as the Checkbuf test, to measure the buffering capacity of resting saliva and to evaluate its correlation with the Ericsson test for resting saliva. Resting saliva was collected from 112 patients. Buffering capacity was assessed with the adapted Checkbuf test and 4 other methods: Ericsson test for resting saliva, Checkbuf test, and commercially available paper and liquid colorimetric tests for stimulated saliva. Data were analyzed by Cohen kappa coefficient to evaluate the agreement between the Ericsson test and the other tests. There was a significant positive agreement between the Ericsson test for resting saliva and adapted Checkbuf test (kappa = 0.708). However, there were no agreements between the Ericsson test and the 3 other tests. This study demonstrated that the adapted Checkbuf test is useful for measuring resting saliva buffering capacity, even for subjects with low salivary flow rates.
    Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 09/2009; 108(4):551-6. · 1.50 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the micro-shear bond strengths and the etching efficacy of a two-step self-etching adhesive system to fluorosed and non-fluorosed enamel. The extracted teeth, obtained from Australian and Japanese patients, were classified according to the severity of fluorosis, using the Thylstrup & Fejerskov index (TFI). Australian teeth were classified as mildly fluorosed (TFI = 1-3), whereas Japanese teeth were classified as non-fluorosed (TFI = 0). Resin composite was bonded to 20 enamel samples using Clearfil SE bond. The bonded samples were stressed at a crosshead speed of 1 mm min(-1) to determine the micro-shear bond strength. To examine the etching efficacy of primer on fluorosed and non-fluorosed enamel, the enamel-surface pH values were directly measured using a micro pH sensor. The non-fluorosed enamel showed significantly higher bond strengths compared with the fluorosed enamel. There was a statistical difference between fluorosed and non-fluorosed enamel regarding the surface pH change before and after application of the Clearfil SE bond primer. The results from this study suggest that water fluoridation has an effect on the acid resistance of enamel surfaces when treated with a two-step self-etching adhesive system and that this effect leads to reduced bond strengths.
    European Journal Of Oral Sciences 05/2009; 117(2):182-6. · 1.42 Impact Factor
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    ABSTRACT: Objectives: To evaluate the effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on surface pH and salivary cariogenic bacteria during intra-oral application for enamel remineralization. Methods: Approval for the study was obtained from the Human Ethics Research committee of the Tokyo Medical and Dental University. Seven healthy subjects (1 males and 6 females) having white spot enamel lesion (WSEL) were recruited (19-64 years). Each subject was recommended to apply a CPP-ACP dental crme (GC Tooth Mousse, GC Corp., Japan) daily with a custom tray for more than 6 months and remineralization progress was assessed. The surface pH values of WSELs before and after CPP-ACP treatment were directly measured using a micro-pH sensor composed of an Ion Sensitive Field Effect Transistor (Horiba Ltd., Japan). On each appointment stimulated whole saliva samples were collected from each subject. On isolation of genomic DNA from each saliva sample a real-time polymerase chain reaction (RT-PCR) assay was performed for quantitative detection of target bacteria; Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus) and mutans streptococci (MS). The average surface pH of WSELs between initial measurement and after 6 months was compared statistically by using repeated measures ANOVA test. Results: Remarkable remineralization progress was observed and surface pH of WSELs after 6 months was significantly higher than that of the initial measurement (p<0.05). The detection frequencies of bacteria were; S. mutans 87.8%, S. sobrinus 46.3% and MS 100%. However, there was no difference in the amount of the any targeted microorganisms all through the experimental periods in any subjects. Conclusion: As the micro-pH sensor could evaluate the change of pH, it might play a potential role in the assessment of WSEL remineralization. Daily use of CPP-ACP with custom tray appears to be useful for WSEL remineralization. This study was supported by the GCOE Program, ICTB at TMDU.
    IADR General Session 2009; 04/2009
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    ABSTRACT: Objectives: This study was designed to evaluate the feasibility of a micro-pH sensor to assess caries risks clinically in relation to quantitative distribution of cariogenic bacteria. Methods: Approval for the study was obtained from the Human Ethics Research Committee of the Tokyo Medical and Dental University. A total of 32 caries samples were obtained from 26 healthy adult patients (22-73 years). Active and arrested dentin caries lesions were selected on clinical and radiological examinations. The surface pH values of caries lesion were directly measured using a micro-pH sensor composed of an Ion Sensitive Field Effect Transistor and a semiconductor with a flat surface (0.7mm diameter) sensing area (Horiba Ltd., Japan). All carious dentin samples were collected from the dentinal carious lesion with a spoon excavator and round bur. On isolation of genomic DNA from each sample a real-time polymerase chain reaction (RT-PCR) assay was performed using ABI PRISM7500 (Applied Biosystems, USA) for quantitative detection of target bacteria; Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus) and mutans streptococci (MS). Surface pH values were compared between active and arrested lesions by Student's t-test. Results: Among 32 samples 15 were diagnosed as active and 17 were diagnosed as arrested dentinal-caries. There were statistically significant differences in pH values between active and arrested dentinal-caries (p<0.05). The detection frequencies of bacteria in active caries were S. mutans 73.3%, S. sobrinus 6.7% and in arrested caries were S. mutans 76.5%, S. sobrinus 35.3%. Interestingly, S. sobrinus were least frequently detected in active caries. Conclusion: The low pH values acquired by the micro-pH sensor in active caries have shown a correlation with the detection frequencies of S. sobrinus. Therefore, the micro-pH sensor appeared to have shown the possibility of chair side assessment of caries risks. This study was supported by the GCOE Program, ICTB at TMDU.
    IADR General Session 2009; 04/2009
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    ABSTRACT: Data on the adhesive strength of new all-in-one adhesives are still relatively limited. This study compared the microshear bond strengths of five recent all-in-one self-etching priming systems (G-Bond, One-Up Bond-F Plus, Clearfil S3 Bond, Adper Prompt L-Pop and Go!) with a widely used two-step self-etching priming system (Clearfil SE Bond). Human molars were sectioned and finished with 600-grit SiC paper. Both enamel and dentin were bonded using adhesives with a 0.7 mm bonding diameter. Bond strengths were tested using a microshear bond test method at a crosshead speed of 1 mm/minute. The mean bond strengths and standard deviations were calculated and analyzed using ANOVA and the Tukey's HSD test. Results showed the two-step self-etching system had significantly higher bond strengths to dentin. However, for enamel bond strength, Clearfil SE Bond showed no statistical difference to G-Bond and Go!; however, all of the other materials were statistically lower. It is necessary to examine these new materials clinically to determine their efficacy.
    Operative Dentistry 07/2008; 33(4):456-60. · 1.31 Impact Factor

Publication Stats

537 Citations
100.65 Total Impact Points

Institutions

  • 1998–2014
    • Tokyo Medical and Dental University
      • • Division of Oral Health Sciences
      • • Department of Restorative Sciences
      • • Department of Operative Dentistry
      Edo, Tōkyō, Japan
  • 2008
    • Victoria University Melbourne
      Melbourne, Victoria, Australia
  • 1995–2005
    • University of Melbourne
      Melbourne, Victoria, Australia

Disciplines