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  • Dentin Bonding Durability of Two-step Self-etch Adhesives with Improved of Degree of Conversion of Adhesive Resins.

    Dentin Bonding Durability of Two-step Self-etch Adhesives with Improved of Degree of Conversion of Adhesive Resins.

    J Adhes Dent. 2017 Feb 10;:

    Authors: Sato K, Hosaka K, Takahashi M, Ikeda M, Tian F, Komada W, Nakajima M, Foxton R, Nishitani Y, Pashley DH, Tagami J

    Abstract
    PURPOSE: To evaluate (1) the initial and long-term microtensile bond strengths of two-step self-etch adhesives with different degrees of conversion (DC); (2) the elastic modulus of the respective adhesive resins; (3) the water sorption of the respective adhesive resins.
    MATERIALS AND METHODS: Two two-step self-etch adhesives, Clearfil SE Bond (CSE) and Clearfil SE Bond 2 (CSE2) were used in this study. The DC was determined using ATR/FT-IR with a time-based spectrum analysis. Midcoronal flat dentin surfaces of 24 human molars were prepared with 600-grit SiC paper for microtensile bond strength (μTBS) testing. CSE and CSE2 were applied to the dentin surfaces according to the manufacturer’s instructions, followed by composite buildups. The μTBS was measured after water storage for 24 h, 6 months, and 1 year. The elastic modulus (before and after 1 month of water immersion) was determined by the three-point flexural bending test and water sorption values by the water sorption test.
    RESULTS: CSE2 showed significantly higher DC than CSE. The μTBS of CSE2 was significantly higher than that of CSE in all water storage periods. One-year water storage decreased the μTBS of CSE; however, it did not decrease that of CSE2. Regarding the polymerized adhesive resins, the elastic modulus of CSE2 was significantly higher than that of CSE before and after water immersion (p < 0.001), and the water sorption of CSE was higher than that of CSE2.
    CONCLUSIONS: The higher DC of adhesive resins of two-step self-etch adhesives resists water aging and improves the initial bond strengths and durability of the resin-dentin bond.

    (28195277) – as supplied by publisher]

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  • Multifactorial logistic regression analysis of factors associated with the incidence of erosive tooth wear among adults at different ages in Tokyo.
    .

    Multifactorial logistic regression analysis of factors associated with the incidence of erosive tooth wear among adults at different ages in Tokyo.

    Clin Oral Investig. 2017 Feb 07;:

    Authors: Kitasako Y, Sasaki Y, Takagaki T, Sadr A, Tagami J

    Abstract
    OBJECTIVES: The aim of this study was to evaluate factors associated with the incidence of erosive tooth wear (ETW) among adults at different ages in Tokyo using multifactorial logistic regression analysis.
    MATERIALS AND METHODS: The study sample consisted of a total of 1108 subjects aged 15 to 89 years in Tokyo, Japan. Two examiners evaluated ETW in a full-mouth recording. The subjects were asked to complete a self-administered daily diet, habit, and health condition questionnaire. Subjects who had frequent acid consumption or gastric reflux and at least one tooth with initial enamel wear were placed in the ETW-positive group, and the remainder of the subjects was placed in the ETW-negative group. Logistic regression analyses were carried out to identify factors collectively associated with ETW.
    RESULTS: Logistic regression analysis showed that greater frequencies of carbonated or sports drink consumption were associated with higher incidence of ETW for all age groups except for 70-89 years. Adults in the 30-39-year group who reported suffering from heartburn were about 22.3 times more likely to develop ETW, while 40-49-year adults who had repeated vomiting were about 33.5 times more likely to exhibit ETW compared with those who did not experience vomiting.
    CONCLUSION: Age-specific dietary habits were clearly observed among adults at different ages in Tokyo, and there were significant differences in intrinsic and extrinsic factors between ETW-positive and ETW-negative groups for each age group.
    CLINICAL RELEVANCE: Both greater frequency of carbonated and sports drink consumption were associated with higher incidence of ETW among adults at different ages in Tokyo.

    (28176000) – as supplied by publisher]

    Bibliography

  • Multifactorial logistic regression analysis of factors associated with the incidence of erosive tooth wear among adults at different ages in Tokyo.
    .

    Multifactorial logistic regression analysis of factors associated with the incidence of erosive tooth wear among adults at different ages in Tokyo.

    Clin Oral Investig. 2017 Feb 07;:

    Authors: Kitasako Y, Sasaki Y, Takagaki T, Sadr A, Tagami J

    Abstract
    OBJECTIVES: The aim of this study was to evaluate factors associated with the incidence of erosive tooth wear (ETW) among adults at different ages in Tokyo using multifactorial logistic regression analysis.
    MATERIALS AND METHODS: The study sample consisted of a total of 1108 subjects aged 15 to 89 years in Tokyo, Japan. Two examiners evaluated ETW in a full-mouth recording. The subjects were asked to complete a self-administered daily diet, habit, and health condition questionnaire. Subjects who had frequent acid consumption or gastric reflux and at least one tooth with initial enamel wear were placed in the ETW-positive group, and the remainder of the subjects was placed in the ETW-negative group. Logistic regression analyses were carried out to identify factors collectively associated with ETW.
    RESULTS: Logistic regression analysis showed that greater frequencies of carbonated or sports drink consumption were associated with higher incidence of ETW for all age groups except for 70-89 years. Adults in the 30-39-year group who reported suffering from heartburn were about 22.3 times more likely to develop ETW, while 40-49-year adults who had repeated vomiting were about 33.5 times more likely to exhibit ETW compared with those who did not experience vomiting.
    CONCLUSION: Age-specific dietary habits were clearly observed among adults at different ages in Tokyo, and there were significant differences in intrinsic and extrinsic factors between ETW-positive and ETW-negative groups for each age group.
    CLINICAL RELEVANCE: Both greater frequency of carbonated and sports drink consumption were associated with higher incidence of ETW among adults at different ages in Tokyo.

    (28176000) – as supplied by publisher]

    Bibliography

  • The effect of curing conditions on the dentin bond strength of two dual-cure resin cements.
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    The effect of curing conditions on the dentin bond strength of two dual-cure resin cements.

    J Prosthodont Res. 2017 Jan 23;:

    Authors: Tagami A, Takahashi R, Nikaido T, Tagami J

    Abstract
    PURPOSE: The purpose of this study was to determine the effect of the curing condition (i.e., the curing mode and restoration thickness) on the tensile bond strength of a dual-cure resin cement applied to dentin.
    METHODS: Indirect composite resin disks (1, 2, and 3mm in thickness) were prepared. The irradiance of a halogen light curing unit through each disk was measured by a curing radiometer. A measurement was also taken for the condition with no disk. Following this, two dual-cure resin cements, Panavia F2.0 and Panavia V5, were polymerized in either dual-cure mode or self-cure mode to bond the composite resin disk to the flat dentin surface. The specimens were sectioned and subjected to a microtensile bond strength (μTBS) test after 24h of water storage. The data were statistically analyzed by two-way ANOVA followed with multiple comparisons by post-hoc Tukey’s test (α=0.05).
    RESULTS: The irradiance values [mW/cm(2)] measured through indirect composite resin disks were 600 (0mm), 200 (1mm), 90 (2mm), and not detected (3mm). Two-way ANOVA indicated that both the curing condition and the type of resin cement affected the μTBS (p<0.001). The μTBS results for Panavia V5 bonded to dentin were significantly higher than those of Panavia F2.0 bonded to dentin (p<0.05).
    CONCLUSIONS: The curing condition affected the tensile bond strength of the dual-cure resin cements to dentin. A newly developed resin cement, Panavia V5, showed higher dentin bonding than Panavia F2.0 in both dual- and self-cure modes.

    (28126243) – as supplied by publisher]

    Bibliography

  • Evaluation of resin infiltration on demineralized root surface: An in vitro study.
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    Evaluation of resin infiltration on demineralized root surface: An in vitro study.

    Dent Mater J. 2017 Jan 20;:

    Authors: Zhou Y, Matin K, Shimada Y, Sumi Y, Tagami J

    Abstract
    The aim of this study was to evaluate the effect of resin infiltration on root caries induced by Streptococcus mutans biofilms. Human premolar specimens were divided to 5 groups: negative control (NC), Clearfil SE Bond (SEB), Icon-etch120s+Icon-infiltrant (HA120), Icon-etch10s+Icon-infiltrant (HA10) and K-etchant10s+Icon-infiltrant (PA10). The resin penetration was observed by fluorescent microscope. Biofilm-induced demineralization was conducted again and observed by swept-source optical coherence tomography and confocal laser scanning microscope. The maximum resin penetration depth (PDmax), lesion depth increase (∆LD), frequency of cervical enamel loss and dentinoenamel junction separation length were measured and statistically analyzed. HA120 showed 138.00±49.25 µm PDmax that was significantly larger than PA10 and SEB (p<0.05). SEB created 136.58±64.73 µm coating layers. HA120 and SEB showed significantly lower ∆LD than NC (p<0.05). Resin infiltration with 120s-HCl pretreatment has got a good penetration ability and preventive effect on root caries, however, an additional risk factor of cervical enamel loss was identified.

    (28111390) – as supplied by publisher]

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  • The influence of elastic moduli of core materials on shear stress distributions at the adhesive interface in resin built-up teeth.
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    The influence of elastic moduli of core materials on shear stress distributions at the adhesive interface in resin built-up teeth.

    Dent Mater J. 2017 Jan 13;:

    Authors: Chiba A, Hatayama T, Kainose K, Nakajima M, Pashley DH, Wakabayashi N, Tagami J

    Abstract
    This study aimed to investigate shear stress distributions in resin built-up teeth using resin composites of varying elastic moduli (E), with or without fiber posts. Three-dimensional mathematical models of a root-filled mandibular premolar tooth were constructed. Resin post and cores were built-up with resin composites of three different E: 12,000, 18,000 and 24,000 MPa, with or without fiber posts. Finite element linear analysis was performed to calculate shear stress distributions at bonding interface between resin core and dentin. Regardless of fiber post insertion, the shear stress on the cervical surface of resin core decreased as the E of resin composites increased. Insertion of fiber posts increased the shear stress on the post surface of resin core, with increases in the E of resin composites. In conclusion, using resin core materials with higher E decreased the shear stress at cervical interface between resin core and dentin regardless of fiber post insertion.

    (28090032) – as supplied by publisher]

    Bibliography

  • Evaluation of sub-surface penetration and bonding durability of self-etching primer systems to Er:YAG laser treated cervical dentin.
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    Evaluation of sub-surface penetration and bonding durability of self-etching primer systems to Er:YAG laser treated cervical dentin.

    Dent Mater J. 2017 Jan 13;:

    Authors: He Z, Chen L, Shimada Y, Tagami J, Ruan S

    Abstract
    This study aimed to investigate self-etching bonding systems penetrating in sub-surface dentin layer after Er:YAG laser irradiation and micro-shear bonding durability over a period of 1 year. Dentin slices obtained from extracted human third molars were prepared. Two self-etching adhesive systems were evaluated: Clearfil SE Bond and Clearfil Tri-S Bond. Specimens were tested for micro-shear bond strength with one of the following treatments: Er:YAG laser irradiation and 600-grit silicon paper polishing at 24 h, 7 days, 6 months and 1 year. The adhesive interfaces between bonding agents and lased cervical dentin were studied. No hybrid layer could be observed for lased dentin. The slim resin tags could be seen penetrating through the lased subsurface layer. Bond strength to lased dentin after 6 months and 1 year were significantly decreased. (p<0.05).

    (28090034) – as supplied by publisher]

    Bibliography

  • Evaluation of sub-surface penetration and bonding durability of self-etching primer systems to Er:YAG laser treated cervical dentin.
    .

    Evaluation of sub-surface penetration and bonding durability of self-etching primer systems to Er:YAG laser treated cervical dentin.

    Dent Mater J. 2017 Jan 13;:

    Authors: He Z, Chen L, Shimada Y, Tagami J, Ruan S

    Abstract
    This study aimed to investigate self-etching bonding systems penetrating in sub-surface dentin layer after Er:YAG laser irradiation and micro-shear bonding durability over a period of 1 year. Dentin slices obtained from extracted human third molars were prepared. Two self-etching adhesive systems were evaluated: Clearfil SE Bond and Clearfil Tri-S Bond. Specimens were tested for micro-shear bond strength with one of the following treatments: Er:YAG laser irradiation and 600-grit silicon paper polishing at 24 h, 7 days, 6 months and 1 year. The adhesive interfaces between bonding agents and lased cervical dentin were studied. No hybrid layer could be observed for lased dentin. The slim resin tags could be seen penetrating through the lased subsurface layer. Bond strength to lased dentin after 6 months and 1 year were significantly decreased. (p<0.05).

    (28090034) – as supplied by publisher]

    Bibliography

  • The influence of elastic moduli of core materials on shear stress distributions at the adhesive interface in resin built-up teeth.
    .

    The influence of elastic moduli of core materials on shear stress distributions at the adhesive interface in resin built-up teeth.

    Dent Mater J. 2017 Jan 13;:

    Authors: Chiba A, Hatayama T, Kainose K, Nakajima M, Pashley DH, Wakabayashi N, Tagami J

    Abstract
    This study aimed to investigate shear stress distributions in resin built-up teeth using resin composites of varying elastic moduli (E), with or without fiber posts. Three-dimensional mathematical models of a root-filled mandibular premolar tooth were constructed. Resin post and cores were built-up with resin composites of three different E: 12,000, 18,000 and 24,000 MPa, with or without fiber posts. Finite element linear analysis was performed to calculate shear stress distributions at bonding interface between resin core and dentin. Regardless of fiber post insertion, the shear stress on the cervical surface of resin core decreased as the E of resin composites increased. Insertion of fiber posts increased the shear stress on the post surface of resin core, with increases in the E of resin composites. In conclusion, using resin core materials with higher E decreased the shear stress at cervical interface between resin core and dentin regardless of fiber post insertion.

    (28090032) – as supplied by publisher]

    Bibliography

  • A pilot study to assess the morphology and progression of non-carious cervical lesions.
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    A pilot study to assess the morphology and progression of non-carious cervical lesions.

    J Dent. 2016 Dec 09;:

    Authors: Sugita I, Nakashima S, Ikeda A, Burrow MF, Nikaido T, Kubo S, Tagami J, Sumi Y

    Abstract
    OBJECTIVE: This longitudinal pilot study aimed to morphologically and quantitatively investigate the progress of non-carious cervical lesions (NCCLs) by using swept-source optical coherence tomography (SS-OCT).
    METHODS: The samples examined comprised sets of NCCL epoxy resin replicas obtained from 10 lesions in 6 patients who attended annual dental visits over 4 or 5 years. SS-OCT images of the replicas were analyzed in terms of the maximum depth (Dmax) and corresponding vertical width (VW) – using an image analyzer to estimate progression of the NCCLs over time.
    RESULTS: It was found that differences between wedge- and saucer-shaped lesions were morphologically distinguished well by the OCT images. There were significant differences in dimensions among Dmax, VW and horizontal width (HW). HW was the largest and Dmax was the smallest. Although no significant differences in absolute values of annual progression rates were found among Dmax, VW and HW, the percentage increase in Dmax was significantly greater compared to VW and HW. The ratios of Dmax to corresponding VW ranged from 0.49 to 1.01 for the wedge-shaped lesions and from 0.13 to 0.44 for saucer-shaped lesions, respectively.
    CONCLUSIONS: The dimensional analysis demonstrated notable progression with large variations. The wedge-shaped lesions appeared to show greater Dmax values compared to the saucer-shaped lesions.
    CLINICAL SIGNIFICANCE: With respect to the depth, the wedge-shaped lesions may progress at a greater rate compared to the saucer-shaped lesions.

    (27956017) – as supplied by publisher]

    Bibliography

  • Three-Dimensional Analysis of Enamel Crack Behavior Using Optical Coherence Tomography.
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    Three-Dimensional Analysis of Enamel Crack Behavior Using Optical Coherence Tomography.

    J Dent Res. 2016 Nov 21;:

    Authors: Segarra MS, Shimada Y, Sadr A, Sumi Y, Tagami J

    Abstract
    The aim of this study was to nondestructively analyze enamel crack behavior on different areas of teeth using 3D swept source-optical coherence tomography (SS-OCT). Ten freshly extracted human teeth of each type on each arch (n = 80 teeth) were inspected for enamel crack patterns on functional, contact and nonfunctional, or noncontact areas using 3D SS-OCT. The predominant crack pattern for each location on each specimen was noted and analyzed. The OCT observations were validated by direct observations of sectioned specimens under confocal laser scanning microscopy (CLSM). Cracks appeared as bright lines with SS-OCT, with 3 crack patterns identified: Type I – superficial horizontal cracks; Type II – vertically (occluso-gingival) oriented cracks; and Type III – hybrid or complicated cracks, a combination of a Type I and Type III cracks, which may or may not be confluent with each other. Type II cracks were predominant on noncontacting surfaces of incisors and canines and nonfunctional cusps of posterior teeth. Type I and III cracks were predominant on the contacting surfaces of incisors, cusps of canines, and functional cusps of posterior teeth. Cracks originating from the dental-enamel junction and enamel tufts, crack deflections, and the initiation of new cracks within the enamel (internal cracks) were observed as bright areas. CLSM observations corroborated the SS-OCT findings. We found that crack pattern, tooth type, and the location of the crack on the tooth exhibited a strong correlation. We show that the use of 3D SS-OCT permits for the nondestructive 3D imaging and analysis of enamel crack behavior in whole human teeth in vitro. 3D SS-OCT possesses potential for use in clinical studies for the analysis of enamel crack behavior.

    (27872333) – as supplied by publisher]

    Bibliography

  • Effect of phytic acid etchant on resin-dentin bonding: Monomer penetration and stability of dentin collagen.
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    Effect of phytic acid etchant on resin-dentin bonding: Monomer penetration and stability of dentin collagen.

    J Prosthodont Res. 2016 Oct 21;:

    Authors: Kong K, Hiraishi N, Nassar M, Otsuki M, Yiu CK, Tagami J

    Abstract
    PURPOSE: Phytic acid (IP6) works well as an etchant in dentin bonding to remove the smear layer due to its acidity and chelating effect. This study compared the etching effect of IP6 with phosphoric acid (PA) and ethylenediaminetetraacetic acid (EDTA) on resin-dentin bond strength, micromorphology of the etched dentin surface and nanoleakage formation along resin-dentin interfaces and compared the protecting effect against collagen degradation.
    METHODS: Dentin disks and flat dentin surfaces were obtained from extracted human teeth. Specimens were etched with 35% PA (15s), 0.5M EDTA (30s) or 1% IP6 (30s). The surfaces and longitudinal sections of the etched dentin disks were observed using field emission scanning electron microscope (FE-SEM). An etch-and-rinse adhesive was used to create composite build up-specimens for microtensile bond strength (μTBS) testing and nanoleakage observation. To evaluate the effect on collagen degradation, demineralized bovine root dentin blocks were challenged with bacterial collagenase and then observed under light microscope.
    RESULTS: PA- and EDTA- treated groups showed significantly lower μTBS when compared to IP6-treated group. PA showed distinct nanoleakage and severe collagen degradation. Only slight nanoleakage was detected in IP6 group. IP6 showed better effect than EDTA in preventing collagen degradation induced by bacterial collagenase.
    CONCLUSIONS: IP6 effectively removed the smear layer and etched dentin, providing high bond strength values and causing minimal nanoleakage and slight collagen degradation.

    (27777071) – as supplied by publisher]

    Bibliography

  • Hesperidin interaction to collagen detected by physico-chemical techniques.

    Hesperidin interaction to collagen detected by physico-chemical techniques.

    Dent Mater. 2016 Oct 19;:

    Authors: Hiraishi N, Maruno T, Tochio N, Sono R, Otsuki M, Takatsuka T, Tagami J, Kobayashi Y

    Abstract
    OBJECTIVE: Dentin collagen can be modified by some plant-derived flavonoids to improve properties of dentin organic matrix. Hesperidin (HPN), a hesperetin-7-O-rutinoside flavonoid, has a potential of dentin modification for being based on evidence that a treatment with HPN may resist collagenase degradation and arrest demineralization of human dentin. In this study, biophysical and molecular-level information on the interaction of HPN and collagen was investigated.
    METHODS: HPN is extracted from citrus fruits. Sample collagenous solution was prepared using atelocollagen (ATCL) as a triple-helical peptide model. We have performed circular dichroism spectroscopic analysis, sedimentation velocity measurement by ultracentrifuge and saturation transfer difference measurement (STD) by NMR on HPN-collagen in solution state.
    RESULTS: The circular dichroism and sedimentation velocity measurement showed the evidence for the molecular interaction between ATCL and HPN, while HPN did not induce any conformational change of ATCL. The STD-NMR study further confirmed this interaction and suggested that HPN interacted with ATCL through its aromatic part, not through its disaccharide moiety.
    SIGNIFICANCE: These findings indicated that HPN is weakly bound to ATCL not causing structural modification of collagen. This interaction may contribute to the preservation of collagen by protecting from collagenase degradation.

    (27771138) – as supplied by publisher]

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  • A comparative study of the susceptibility of cut and uncut enamel to erosive demineralization.

    A comparative study of the susceptibility of cut and uncut enamel to erosive demineralization.

    Dent Mater J. 2016 Oct 22;

    Authors: Lin WT, Kitasako Y, Nakashima S, Tagami J

    Abstract
    This study aimed to evaluate the susceptibility of cut and uncut enamel surfaces to an erosive challenge and to examine the resultant characteristics/morphological changes. Ten extracted human incisors were used for preparation of enamel samples, and samples were immersed in citric acid. After 3 (total 3 min) and 6 cycles (total 6 min) of erosive challenges, surface loss (SL) and morphological changes were measured using scanning microscopy and FIB-TEM. Ca release (CA) and surface hardness (SH) were measured using a calcium-sensitive electrode and hardness tester respectively. Mean values of all measurements were statistically analyzed by using a t-test. Uncut enamel samples had significantly lower SL and greater SH than cut enamel (p<0.01). Cut enamel samples after 3 cycles showed higher CA compared with those from uncut enamel samples (p<0.05). Cut enamel was shown to be more susceptible to acidic dissolution and deeper acid penetration than uncut enamel after erosive demineralization.

    (27773896) – as supplied by publisher]

    Bibliography

  • Effects of C-factor on bond strength to floor and wall dentin.

    Effects of C-factor on bond strength to floor and wall dentin.

    Dent Mater J. 2016 Oct 01;

    Authors: Yoshikawa T, Sadr A, Tagami J

    Abstract
    This study evaluated the effect of C-factor on the bond strength of a resin composite to floor and wall dentin using two adhesive systems. Box-form cavities were prepared on human molars, following the walls of half of the cavities were removed to create flat dentin surfaces for bonding. Each specimen was then restored using one of two adhesives (Clearfil SE Bond or Clearfil tri-S Bond) and filled or built up using Z100 resin composite. After light-curing, the specimen was cut perpendicular to the bonded surface parallel to the floor or wall to obtain beams. The micro-tensile bond strength to the flat floor, flat wall, cavity floor, or cavity wall was determined. Resin composite bonded more strongly to the flat wall dentin than to the flat floor dentin, regardless of the adhesive system used. Bonding to the cavity wall was higher affected by C-factor than to the cavity floor.

    (27725368) – as supplied by publisher]

    Bibliography

  • Optical analysis of enamel and dentin caries in relation to mineral density using swept-source optical coherence tomography.

    Optical analysis of enamel and dentin caries in relation to mineral density using swept-source optical coherence tomography.

    J Med Imaging (Bellingham). 2016 Jul;3(3):035507

    Authors: Ueno T, Shimada Y, Matin K, Zhou Y, Wada I, Sadr A, Sumi Y, Tagami J

    Abstract
    The aim of this study was to evaluate the signal intensity and signal attenuation of swept source optical coherence tomography (SS-OCT) for dental caries in relation to the variation of mineral density. SS-OCT observation was performed on the enamel and dentin artificial demineralization and on natural caries. The artificial caries model on enamel and dentin surfaces was created using Streptococcus mutans biofilms incubated in an oral biofilm reactor. The lesions were centrally cross sectioned and SS-OCT scans were obtained in two directions to construct a three-dimensional data set, from the lesion surface (sagittal scan) and parallel to the lesion surface (horizontal scan). The integrated signal up to [Formula: see text] in depth (IS200) and the attenuation coefficient ([Formula: see text]) of the enamel and dentin lesions were calculated from the SS-OCT signal in horizontal scans at five locations of lesion depth. The values were compared with the mineral density obtained from transverse microradiography. Both enamel and dentin demineralization showed significantly higher IS200 and [Formula: see text] than the sound tooth substrate from the sagittal scan. Enamel demineralization showed significantly higher IS200 than sound enamel, even with low levels of demineralization. In demineralized dentin, the [Formula: see text] from the horizontal scan consistently trended downward compared to the sound dentin.

    (27704033) – in process]

    Bibliography

  • White spot lesion remineralization by sugar-free chewing gum containing bio-available calcium and fluoride: A double-blind randomized controlled trial.
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    White spot lesion remineralization by sugar-free chewing gum containing bio-available calcium and fluoride: A double-blind randomized controlled trial.

    J Dent. 2016 Sep 14;

    Authors: Sugiura M, Kitasako Y, Sadr A, Shimada Y, Sumi Y, Tagami J

    Abstract
    OBJECTIVES: To assess the effect of chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and fluoride on white spot lesion (WSL) remineralization in comparison with POs-Ca or placebo (control) chewing gums, in double- blind, randomized, controlled trial.
    METHODS: Thirty-seven healthy subjects, who had at least one WSL, with an ICDAS score of 2 or 1, were recruited for this study. The subjects were randomly divided into three groups (control, POs-Ca, POs-Ca+F) and chewed two slabs of each gum three times every day for 3 months. WSLs were assessed using ICDAS criteria and optical boundary depth (BD) by optical coherence tomography (OCT) system at a monthly recall. Data were analyzed by Wilcoxon rank-sum test and Wilcoxon signed rank test with Bonferroni corrections at 0.05 significance level.
    RESULTS: Visual score changes from ICDAS score 2 to score 1 over the course of the study were observed; control (30%), POs-Ca (48%) and POs-Ca+F (45%). Unlike the control gum, chewing POs-Ca and POs-Ca+F gums resulted in significant changes in the mean value of BD over the 3 months course of the study (p<0.05). There was a significant difference in mean value of BD after first month between POs-Ca+ F and control groups (p<0.05).
    CONCLUSIONS: This study highlighted the importance of calcium and fluoride ion bioavailability in the reinforcement of demineralized enamel lesions by chewing gums. Furthermore, adding fluoride to POs-Ca might speed up the remineralization progress on natural WSL.

    (27639827) – as supplied by publisher]

    Bibliography

  • Effects of zinc fluoride on inhibiting dentin demineralization and collagen degradation in vitro: A comparison of various topical fluoride agents.

    Effects of zinc fluoride on inhibiting dentin demineralization and collagen degradation in vitro: A comparison of various topical fluoride agents.

    Dent Mater J. 2016 Aug 20;

    Authors: Thanatvarakorn O, Islam MS, Nakashima S, Sadr A, Nikaido T, Tagami J

    Abstract
    Root caries is developed because of demineralization followed by enzymatic collagen degradation. This in vitro study aimed to examine the inhibitory efficacy of ZnF2 on dentin demineralization and collagen degradation. Bovine dentin specimens were treated either with ZnF2 or HCl-acidified ZnF2 (ZnF2/HCl) and then demineralized. Anti-demineralization efficacy was assessed by TMR as mineral loss (ΔZ). The efficacy was compared with silver diammine fluoride (SDF), KF, and acidulated phosphate fluoride (APF). For evaluating anti-collagen degradation, EDTA-demineralized dentin specimens were treated by one of four fluoride agents [SDF, APF, ZnF2/HCl, NaF] followed by collagenase challenge. The eroded depth of collagen layer in the lesion was assessed using optical microscope. ΔZ of SDF, KF, ZnF2/HCl, and APF were significantly lower compared with ZnF2 and Control (no treatment). Regarding anti-collagen degradation, SDF and ZnF2/HCl demonstrated a significant difference in the eroded depth compared with Control. Although SDF possessed higher efficacy, ZnF2/HCl might be beneficial as a staining-free agent.

    (27546855) – as supplied by publisher]

    Bibliography

  • Effect of enamel margin configuration on color change of resin composite restoration.

    Effect of enamel margin configuration on color change of resin composite restoration.

    Dent Mater J. 2016;35(4):675-83

    Authors: Aida A, Nakajima M, Seki N, Kano Y, Foxton RM, Tagami J

    Abstract
    This study aimed to investigate the effect of enamel margin configuration on color change of resin composite restoration. Enamel disks of 1.0 mm-thick were sliced from sixty bovine anterior teeth and divided into three groups by margin configuration (non-bevel, 45-degree bevel and 45-degree reverse-bevel). The color measurements (L*C*h* values) at the restored bovine enamel disk with resin composite (Estelite Asteria, Estelite Pro, Kalore, Clearfil Majesty) were performed using a digital camera with CIE XYZ color gamut (RC500). All the resin composite restorations with non-beveled and beveled cavities significantly increased L* values compared with the control composite disks (p<0.05). The bevel preparation increased L* values toward the enamel-composite border with gentle inclination, while the reverse-bevel preparation was significantly lower L* values at the enamel-composite border than the non-bevel preparation (p<0.05). Enamel margin configuration affected color shifting of resin composite restoration and color adjustment of the border.

    (27477235) – in process]

    Bibliography

  • Effects of brushing timing after erosive challenge on enamel loss in situ: White light interferometer and nanoindentation study.

    Effects of brushing timing after erosive challenge on enamel loss in situ: White light interferometer and nanoindentation study.

    Dent Mater J. 2016;35(4):613-20

    Authors: Tsuda Y, Kitasako Y, Sadr A, Nakashima S, Tagami J

    Abstract
    This in situ study aimed to evaluate effects of waiting periods after erosive challenge before toothbrushing on enamel abrasion and nanoindentation hardness. Ten subjects wore intraoral appliances each with a set of 4 bovine enamel blocks. The enamel blocks were subjected to 2 cycles a day for 3 days as follows; intraoral exposure to form acquired pellicle and extraoral erosion followed by either 0, 3, 30 or 60 min intraoral exposure and then brushing, which was performed using an automatic brushing machine. Abrasive loss was assessed by white light interferometry. Nanoindentation was performed to calculate relative hardness. Abrasion and relative hardness were statistically analyzed by ANOVA. Abrasive loss was significantly less in groups exposed to saliva compared with 0 min (p<0.05); there was no significant difference between 30 and 60 min (p>0.05). Relative hardness was statistically higher after intraoral exposure, but no differences existed among any intraoral exposure periods (p>0.05).

    (27477227) – in process]

    Bibliography