Purpose: During the initial stages of carious lesions, decayed lesions are characterized by dissolution of the hydroxyapatite, and estimation of the amount of enamel subsurface porosity can be used to detect and quantify the early stages. Through being able to detect and diagnose carious lesions at an early stage, dentists can prevent progression of the decay, and avoid the need for invasive removal of sound tooth structures. Previous studies have demonstrated that Time-Domain Optical Coherence Tomography (TD-OCT) can be used to image the demineralization of early artificial carious lesions. However, an analytical method for quantifying coronary lesion severity has not been developed. The aim of this study was to evaluate a new method of analyzing OCT images for the evaluation of enamel demineralization. Methods: After slicing bovine incisors, each slab was trimmed into a rectangular form (4×4×2 mm) using #2,000-grid silicon carbide paper. Specimens were treated with lactic acid buffer solution and then placed in artificial saliva (AS) or in distilled water (DW). The scanning probe connected to the TD-OCT was set at a fixed distance (2.0 mm) from the enamel surface. The scanning beam was set perpendicular to the surface of the tooth. From the OCT images, the peak intensity and width at [1/e²] were obtained. The data for each group were analyzed by a repeated measures analysis of variance (ANOVA) followed by a Tukey-Kramer post-hoc multiple comparison (α=0.05). Results: The signal intensities for the DW group significantly increased from -72.3 dB to -44.5 dB, while there were no changes in the width of [1/e²]. The signal intensities for the AW group significantly decreased from -52.7 dB to -67.2 dB, and the width of [1/e²] significantly increased. The changes in signal intensities and [1/e²] might be related to the reflection of light on the tooth surface. Conclusions: The current study demonstrated that the TD-OCT successfully tracked the development of mineralization and that [1/e²] measurement may be a suitable indication of tooth demineralization.

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Purpose: Although the prevalence of dental caries has declined markedly, the disease is still a major problem for both adults and children. Fluoride-containing products reduce tooth decay via topical mechanisms which include inhibition of demineralization and enhancement of remineralization. However, few studies have evaluated the effect of prophylaxis paste treatment with fluoride on bonded restorations to dentin. The purpose of this study was to investigate the influence of fluoride contained prophylaxis paste treatment on the dentin bond strengths of single-step self-etch adhesives. Methods: The adhesive systems employed in this study were three self-etch systems: BeautiBond (Shofu), Bond Force (Tokuyama Dental) and G-Bond Plus (GC), and an etch-and-rinse system: Single Bond Plus (3M ESPE). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600-grit silicon carbide paper to expose labial dentin. Prophylaxis pastes with fluoride (Merssage Cleargel, Shofu) and without fluoride (Pressage, Shofu) were applied on the tooth surface once on the first day, or twice a day for 7 days. Adhesives were applied and resin composites were condensed into a mold on the dentin and light irradiated. The finished specimens were transferred to distilled water, and stored at 37℃ for 24 h. Ten specimens per group were tested in shear mode in a universal testing machine (Type 5500R, Instron) at a crosshead speed of 1.0 mm/min. One-way ANOVA and Tukey HSD test (α=0.05) were performed within each adhesive system. Results: The mean bond strength ranged from 5.7 to 15.7 MPa for self-etch adhesives and from 8.3 to 19.5 MPa for the etch-and-rinse system. The dentin bond strength of the self-etch adhesive systems decreased after treatment with prophylaxis pastes regardless of fluoride content. For the etch-and-rinse system, significantly lower bond strengths were obtained for the immediate and the 7-day treatment groups. The reasons for the decreased bond strengths were thought to be the presence of fluoride and remnants of prophylaxis paste, such as glycerin, silica and pumice, in dentinal tubules. These remnants might reduce the etching effect and prevent resin monomer penetration into dentin, leading to decreased bond strengths. Conclusion: The results of this in vitro study indicate that the use of prophylaxis paste prior to self-etch adhesive application reduces the dentin bond strength of single-step self-etch adhesives.

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Purpose: Prevotella intermedia, a gram negative black-pigmented anaerobic rod, is known as an initial colonizer on the tooth surface. Some clinical isolates of this organism produce mannose-rich exopolysaccharides (EPS) and form biofilms that contribute to its pathogenicity. Methods: In order to see whether this organism has the capacity to form single-species biofilm on titanium dental implants, the behaviors of three different strains of P. intermedia (strains 17, 17-2 and ATCC 25611) on titanium discs and on titanium implant fixtures vertically placed in bacterial cultures were observed by means of scanning electron microscopy. In addition, inhibitory effects of protein inhibitors such as erythromycin (EM), clarithromycin (CAM), streptomycin (SM) and tetracycline (TC) at 1/2 MIC on P. intermedia biofilm on the implant fixture were examined. Results: Both ATCC 25611 and, to a lesser extent, strain 17 adhered to the titanium disc. Although strain 17 secreted a large number of extracellular matrices on the discs, ATCC 25611 did not. Although ATCC 25611 formed microcolonies on titanium fixtures, the other two strains did not. When the fixture in culture medium was inoculated with a mixed culture of ATCC 25611 and strain 17, three-dimensional biofilm structures with a dense meshwork were constructed. The biofilm formation on the titanium fixture was reduced by the protein inhibitors. The effects of macrolides (EM and CAM) were relatively stronger than those of SM and TC. Conclusion: These results suggest that P. intermedia can form single-species biofilm on titanium dental implants when adhesive cells and cells spontaneously producing an extracellular matrix react with each other.

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Purpose: In recent years, the number of patients with transient dentin hypersensitivity to cold water and abrasion pain without dental caries has been increasing. In the treatment of dentin hypersensitivity, the first choice is frequently the topical application of medicament due to its simplicity and immediate effect. A wide range of products with different action mechanisms are available for clinical use. The present study focused on dentin desensitizers and their dentinal tubular solubility. The dentin permeability inhibition ratio was measured using a model of hypersensitive dentin. In addition, the influence of post-application preservation conditions on serial changes in the permeability inhibition ratio was evaluated. Methods: Dentin discs were prepared from extracted human molars for use as hypersensitivity model specimens. The specimens were applied to a device based on Pashley et al., with modifications, and the pulpal pressure was determined to be 25 mmHg. After applying four different dentin desensitizer products, Gluma Desensitizer (GL), Super Seal (SS), MS Coat One (MO), Nanoseal (NS), Teethmate Desensitizer (TD) and Shield Force Plus (SP), the specimens were stored in distilled water (DW group) or artificial saliva (AS group) for 24 h and for one week, and the dentin permeability was measured. Results: In the DW group of all dentin desensitizers, the dentin permeability inhibition ratio one week after application decreased or showed a serial decrease in comparison with that immediately after application. In the AS group of SS, MO, NS and TD, the ratio one week after application increased or showed a serial increase in comparison with that immediately after application. In the AS group of GL and SP, the ratio one week after application showed a serial decrease in comparison with that immediately after application. Conclusion: When the specimens were stored in distilled water, all dentin desensitizers showed a decrease in the sealability of the dentinal tubules. When the specimens were stored in artificial saliva imitating the human intraoral cavity, dentin desensitizers Super Seal, MS Coat one, Nanoseal and Teethmate Desensitizer showed a serial increase in the sealability of the dentinal tubules, suggesting a bioactive action.

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Purpose: The purpose of this study was to clarify the canal shaping abilities of the following three files: Reciproc (RE), which is used in reciprocating rotary motion with a single nickel-titanium rotary (Ni-Ti) file; ProTaper (PT), which is used in continuous forward rotation with different taper Ni-Ti files; and the stainless steel K file (SSK), which is used by hand with multiple files. Methods: Twenty-seven transparent resin blocks with curved canals were used. The working time and force required for push load and pull-out load during root canal preparation were measured. Superimposed images were used to compare changes in root canal shape both before and after preparation. The size of debris produced during the preparation was calculated using image analysis software. All data were subjected to statistical analysis. Results: Significant differences were observed between groups in total preparation time. RE required the least amount of time while SSK required six times as much time as that with Ni-Ti files. The push and pull-out loads were significantly smaller in the order of PT, RE and SSK. The force required (mean±standard deviation, gf) for both PT and RE were as follows: PT, push 233±58 gf, pull 127±36 gf; and RE, push 370±92 gf, pull 353±58 gf. The superimposed images revealed the presence of unshaped root canal walls both inside the curvature and outside the orifice in SSK; however, images showing the results of shaping with Ni-Ti files indicated that the curved canals were cut uniformly and circumferentially. Step formation and debris clogging were observed in SSK, but not in PT or RE. The debris in canals shaped by Ni-Ti appeared larger than that in canals shaped by the other types of files. Conclusion: These results suggest that reciprocating rotary single and multiple Ni-Ti files can enable proper canal preparation with uniform shaping inside and outside the canal walls in a short time.

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Purpose: Dental intervention in conjunction with cancer treatment is suggested in cancer base hospitals such as cancer centers and university hospitals to prevent oral problems in cancer patients. Our department set up an oral care support team in July 2011, and has been working to reduce postoperative complications in head and neck cancer patients. The present paper reports the activities of the oral care support team. Methods: A retrospective observation study of the patients' background, number of intervention cases, complications, and dental treatment at intervention was performed in head and neck cancer patients referred from the otolaryngology department between July 1, 2011 and December 31, 2012. Results: The subjects were 102 head and neck cancer patients (81 males and 21 females) with an average age of 64.1 years. Primary diseases were 29 oral cancers, 24 oropharynx cancers, 8 larynx cancers, 6 primary unknown cancers, 5 nasopharyngeal cancers, 4 nasal cavity cancers, 4 salivary gland cancers, and 4 others. Half of these cases were treated surgically, followed by a combination of chemotherapy and radiation treatment in the otolaryngology department. Approximately 80% of the cases received intervention by the oral care support team before the initiation of cancer treatment. The monthly average number of intervention cases was 6. The rate of postoperative complications was 8.8%. Treatments given by the oral care support team included oral health treatment (tooth and oral mucosal care) in all cases, followed by surgical treatment in 37 cases (35.3%), prosthetic treatment in 16 cases (15.7%), conservation treatment in 5 cases (4.9%), endodontic treatment in 5 cases (4.9%), and caries prevention treatment in 5 cases (fluoride application to tooth surface, 4.9%). Conclusion: Almost all the referred patients required oral functional maintenance. There were no serious adverse events due to intervention by the oral care support team. Further investigation is necessary to establish appropriate therapeutic policy guidelines for dental diseases requiring oral maintenance.

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Purpose: Inflammatory cytokines such as tumor necrosis factor-α (TNF-α) were previously shown to be secreted in pulpitic tissue during the caries process. Matrix metalloproteinases (MMPs) such as MMP-1, 2, 3, and 14 were also shown to be expressed in inflamed dental pulp. MMP-3 can degrade the extracellular matrix (ECM) and activate other MMPs. MMP-3 is considered to be involved in wound healing, inflammation, and tumor initiation. Dental pulp destruction may be regulated, in part, by MMP-3, and other MMPs activated by MMP-3 have been shown to regulate the degradation and regeneration of dental pulp. Ras-related C3 botulinum toxin substrate 1 (Rac1) is a pleiotropic regulator of many cellular processes, including cell growth, cytoskeletal reorganization, and the activation of protein kinases. We hypothesized that Rac1 may negatively regulate the production of MMP-3 from human pulp fibroblasts (HPFs). To test this hypothesis, we isolated and purified HPFs from healthy donors and stimulated them with TNF-α. Methods: HPFs were incubated in serum-free α-MEM containing TNF-α (0, 10, 20, 50, or 100 ng/ml) for 24 h with or without the Rac1 inhibitor, NSC23766. The production of MMP-3 and activation of Rac1 by TNF-α were evaluated by the phosphorylation of Rac1 and MMP-3 antibodies using western blot analysis. Results: We demonstrated that MMP-3 was produced from HPFs in response to TNF-α in a Rac1-dependent manner. TNF-α-induced the production of MMP-3 without affecting the total production of MMP-2. Blocking Rac1 activation with NSC23766 significantly enhanced the TNF-α-induced production of MMP-3 without affecting the total production of MMP-2. Conclusion: These results suggest that Rac1 prevents pulpitis by negatively regulating the production of MMP-3 in HPFs.

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Purpose: Major periodontopathic bacteria settle in all niches of the oral cavity of periodontitis patients, and spread throughout the oral cavity. The purpose of this study was to examine the microbiological effects of a comprehensive oral care regimen (brushing, flossing, gargling) on periodontopathic bacterial counts and the concentration of volatile sulfur compounds (VSC) in the palatine tonsils, tongue coating, and periodontal pockets of chronic periodontitis patients. Methods: Forty-three chronic periodontitis patients were randomly divided into two groups (test group, N=23; control group, N=20), and the concentration of intraoral volatile sulfur compounds (VSCs) was measured and samples were collected in several niches of the oral cavity (palatine tonsil swabs, tongue coating, subgingival plaque). The test group continuously underwent a three-step regimen (brushing, flossing, gargling), and the control group continuously underwent conventional mouth cleaning (brushing only). Measurements and sampling were performed again after 4 weeks. Periodontopathic bacterial counts were quantified using a modified Invader Plus assay, and VSC concentrations were measured by simple gas chromatography. Results: In the test group, the total bacteria (p<0.05), Prevotella intermedia (p<0.01), and Tannerella forsythia (p<0.05) counts of the palatine tonsil swabs decreased significantly. In addition, the total bacteria (p<0.05) and T. forsythia (p<0.05) counts of the periodontal pockets also decreased significantly. There were no significant differences in any of the species or sites in the control group. A significant reduction in the number of individuals showing values above the methyl mercaptan olfactory threshold level was exhibited in the test group (p<0.05). There were no significant differences of H_2S and CH_3SH in the control group, and H_2S in the test group. Conclusion: The comprehensive oral care was effective in reducing bacterial counts in the tonsils and periodontal pockets, and CH_3SH concentrations.

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Purposes: Leucine-rich amelogenin peptide (LRAP) is an amelogenin splicing variant, and is suggested to be a signal peptide that promotes the maturation of osteoblasts as well as the proliferation and migration of periodontal ligament cells. Recently, amelogenin expression has been reported in cartilage in vivo. However, the involvement of LRAP in cartilage formation is unknown. The purpose of this study was to clarify the function of LRAP in mesenchymal cells during chondrogenic lineage differentiation. Methods: After removal of the limb buds of embryonic day 10 C57BL6/CrSlc mouse embryos, the cells were dissociated by trypsin/collagenase treatment and then applied to micromass culture. Recombinant porcine LRAP, which has 85% homology with mouse LRAP, was added to the medium at 0.1, 1, and 10 ng/ml. Alcian Blue staining was performed at 2, 4, and 6 days of culture, and the intensity was measured by the absorbance of the solubilized micromass cultures. To assess the effect of LRAP on cell proliferation, a BrdU assay was performed at 24 and 48 hours. Total RNA was extracted at 12, 24, and 48 hours, and subjected to semi-quantitative RT-PCR analysis of chondrogenic differentiation marker genes Sox9, collagen type II, and aggrecan. One-way analysis of variance (ANOVA) and two-way ANOVA were performed using Bonferroni's multiple comparison as a post-hoc test. Results: At 24 and 48 hours after addition of LRAP, the number of BrdU-positive cells was significantly increased in a concentration-dependent manner compared with that in the control. Alcian Blue-positive nodules appeared in micromass cultures after 2 days. In addition, at 2, 4 and 6 days of culture, the intensity of Alcian Blue staining was significantly increased by LRAP in a concentration-dependent manner compared with that in the control. Furthermore, Sox9 gene expression was significantly increased by LRAP after 24 and 48 hours of culture. Gene expression of collagen type II and aggrecan was also increased by LARP after 48 hours of culture compared with that in the control. Conclusion: These results suggest that LRAP promotes the proliferation of mesenchymal cells derived from the mouse limb bud, and increases chondrogenic marker gene expression-involved production of chondrogenic matrices as indicated by Alcian Blue staining in micromass cultures. Our study may provide useful information for further investigation of the application of amelogenin proteins in cartilage regeneration.

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Purpose: Accidentally exposed dental pulp has been conventionally treated by means of calcium hydroxide formulations. Recently, Mineral Trioxide Aggregate (MTA) has been widely used for direct pulp capping. Though MTA can adequately heal the wound-exposed pulp with good dentin-bridge formation, it has problems that need to be improved such as complicated clinical manipulation and long setting time. A new light-cured resin-modified pulp capping material containing calcium silicate and highly hydrophilic monomer has been developed. Therefore, this particular study was conducted to examine the healing ability of this newly developed pulp capping agent compared with that of MTA, by investigating histopathological changes of wound-exposed rat pulp. Materials and Methods: Cavities with an exposed pulp area were prepared in the maxillary first molars of Wistar rats. After irrigation using alternating solutions of 10% sodium hypochlorite and 3% hydrogen peroxide, the pulps of the maxillary right first molars were capped with TheraCal LC (Bisco) and light-cured for 20 seconds (TCL group). In the same way, the maxillary left first molars were capped with ProRoot MTA (Dentsply-Sankin) and were left for 5 minutes (MTA group). After they were set, these cavities were sealed with Super Bond (Sun Medical), and the opposing mandibular teeth were extracted to avoid occlusion. After 7 or 14 days, the rats were sacrificed, and each tooth was fixed, decalcified, and prepared for paraffin-embedded sections. They were stained with hematoxylin-eosin (HE) for histological examination of pulpal changes. Results: After 7 days, histopathological evaluation demonstrated slight chronic inflammatory cell infiltration, and complete or almost complete dentin-bridging in both TCL and MTA groups. After 14 days, the inflammatory response was reduced, and complete tubular dentin-bridges were observed underneath the exposed area in both groups. Conclusion: This particular study revealed that the newly-developed and easy-to-use pulp capping material exhibited the excellent reparative healing ability of the exposed pulp, which was equivalent to MTA.

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Purpose: It was revealed by dental microscope that there were a large number of cracks not only in tooth roots but also in tooth crowns. These cracks occurred or progressed because of cavity preparation, premature contact, injury and aging. Cracks that occur during preparation may cause postoperative pain, falling-off of the restorative materials, pulpitis, secondary caries and tooth fracture. In this study, we analyzed enamel cracks when extracted human tooth cavities were prepared by various instruments. Methods: Before all extracted teeth were used in this study, the enamel surface without cracks was observed by laser microscope (Olympus 1100). Four kinds of preparation apparatus and five kinds of burs and tips were used for cavity preparation and were compared and evaluated. The four preparation apparatuses were as follows: air turbine, micromotor, Er. Cr: YSGG laser (Waterlase C100; Biolase Technology) and supersonic wave (P-max; with each cutting apparatus made by Satelec). In all extracted teeth, a standard cavity was formed in the labial side under water to avoid the influence of quantity of water, and the influence of fever when preparing the cavity, and the generation of enamel cracks was evaluated after cavity preparation. Furthermore, to evaluate the influence of the shape of the bur (round type or cylinder type) on crack generation, a diamond bur, carbide bur and laser tips were used for preparing enamel cavities and the influence of the bur type and apparatus on crack generation around the cavity was evaluated. The burs and tips used for cavity preparation are shown below. ・Laser tip S (cylinder type, 750μm diameter), Biolase Japan ・Carbide round bur #4 (1.4 mm diameter), SS White ・Diamond fissure bur 835-012 (cylinder type, 1.4 mm diameter), Diatec ・Diamond round bur F-012XL (round type, 1.2 mm diameter), Hinatawada seimitsu MFG ・Carbide fissure bur #1557 G (cylinder type, 1.4 mm diameter), CEI All prepared cavities were observed by the Olympus 1100 laser scanning microscope and the frequency and pattern of cracks and chipping were analyzed. Results: The enamel margin of the cavity was occurred the microcrack formed by rotary preparation appliance and supersonic wave apparatus, but was not induced by the preparation with the laser apparatus. As the cavity preparation was performed by the diamond fissure burs, It was showed that was hard to produce a microcrack than a diamond round burs, and this tendency was also seen by usage of the carbide bar. Conclusion: The usage of the preparation appliance was shown to cause pulpitis and fracture of a tooth because a microcrack was generated at the cavity margin of the enamel. From this study, it was shown when we prepared with the laser appliance+laser tip and the micromotor+diamond fissure burs with the rotary preparation appliance controlled the occurrence of the microcrack.

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Purpose: This study was designed to evaluate the clinical efficacy of bacterial counter, a newly-developed device for measuring the bacterial counts of dental plaque, by examining whether the device can assess oral cleanliness quickly and easily at the chair-side during clinical practice and whether the values measured by the device provide an indication of the oral hygiene status. Materials and Methods: The number of plaque bacteria collected from Ramfjord index teeth of five subjects before (#16, #21, #36, #41) and after (#26, #11, #46, #31) brushing was measured by the device. The results were compared with the conventional anaerobic culture method. In addition, the total number of plaque bacteria collected from four representative Ramfjord index teeth (#16, #21, #36, #41) gathered from 29 new subjects was compared with the data collected by another well-known bacterial plaque index: the Plaque Control Record (O'Leary's PCR) technique. Results: The device effectively detected the reduction of plaque bacteria (p<0.001) after brushing. A positive correlation was found between the two measurement methods both before and after brushing (γ=0.72, γ=0.78, p<0.001). Furthermore, there was a significant correlation between the total number of plaque bacteria collected from the four representative teeth and O'Leary's PCR values (γ=0.59, p<0.01). Conclusion: It is possible to determine the quantity of plaque bacteria quickly and easily using the Bacterial Counter with the same reliability as the conventional anaerobic culture method and O'Leary's PCR. This study indicated that this device would be clinically useful for the assessment of oral hygiene status.

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Purpose: Self-adhesive resin cements (SARCs) have been marketed to simplify clinical procedures and overcome the technique sensitivity of multiple-step systems. However, the dentin bonding performance under different light irradiation conditions of the cement is not known. This study monitored the chronological change of dentin bond strengths of SARCs. Methods: Three SARCs: Clearfil SA Cement Automix (SA; Kuraray Noritake Dental), RelyX Unicem 2 Automix (UC; 3 M ESPE) and BeautiCem SA (BC; Shofu), were used. Bovine dentin was wet-ground with #600 SiC paper. Resin columns (4 mm in diameter, 2 mm in height) were cemented and light-irradiated with the power density of 600 mW/cm^2 or not irradiated (chemical-cured). The shear bond strengths of 10 specimens per group were measured at a crosshead speed of 1.0 mm/min after 10 min, 1, 6, 12, and 24 h storage in a chamber at 37±1℃, 90±5 RH%. Statistical analysis was done to test for the presence of a significant difference between the mean bond strength at each test time at a significance level of 0.05. The time at which there was a significant increase in bond strength was identified as "time of increase in bond strength". Results: The dentin bond strength increased with prolonged specimen storage time. When the specimens were light-irradiated, higher bond strengths were obtained compared to those specimens without irradiation. The fracture mode of the UC specimens without irradiation changed from adhesive failure to mixed failure after 24 h storage. When the specimens were light irradiated, cohesive failure in the resin was observed for UC, and cohesive failure in the cement was observed for BC. Conclusion: The results of this study indicated that the chronological change in the dentin bond strengths of the SARCs was affected by the light irradiation of the specimen. Light irradiation with a sufficient power density is necessary to achieve optimal dentin bond strength, even in materials with a dual-cured setting reaction.

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Purpose: WaveOne and Reciproc nickel-titanium (Ni-Ti) systems are designed specifically for preparing the root canal to an adequate size and for tapering with only one file under reciprocating motion. This study evaluated the shaping ability of WaveOne and Reciproc in comparison with ProTaper, with regard to the working time and postpreparation canal in simulated curved canals. Methods: Sixty simulated resin block canals with angle of curvature of 30° were divided according to the Ni-Ti rotary system used for canal preparation into 4 groups of 15 samples each: WaveOne Small, WaveOne Primary, Reciproc R25, and ProTaper group. The preparation working time was recorded, and all canals were scanned by using an Olympus SZX16 and digital camera DP71 system before and after instrumentation to evaluate canal transportation at 1, 2, 3, and 5 mm from the apex. The significance level was set at p<0.05. Results: The working time taken for WaveOne and Reciproc were significantly shorter than that for ProTaper. WaveOne Small exhibited a significantly lower mean of inside canal transportation than outside canal transportation. There was no significant difference between all experimental groups in outside canal transportation (p>0.05). Conclusions: The WaveOne and Reciproc Ni-Ti systems can be safely and quickly used to the full working length, resulting in satisfactory preservation of the original canal shape.

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Purpose: The purpose of this study was to examine how differences in the surface roughness of composite resin from dental abrasives used in professional mechanical tooth cleaning affect discoloration of the tooth surface. Materials and methods: Cylindrical tooth specimens were fitted with rings with a diameter of 5 mm and a height of 3 mm that were filled with Clearfil Majesty LV and irradiated with light to harden. After hardening was confirmed, the specimen was immersed in 37℃ distilled water for 24 hours. The surface was then polished under water with waterproof abrasive paper up to 1,000 grit, and the resulting surface was used as the standard polished surface. Specimens were then placed in a 37℃ incubator filled with coffee (group C) or red wine (group W) for four weeks, after which the color of the surface was measured with a VSS300H micro spectrophotometer and evaluated with an L*a*b* surface color system. Results: We observed less unevenness forming on the surface with a decreasing relative dentin abrasion value of the final polishing paste used. There were no statistically significant color differences in either the group C or group W specimens due to differences in surface roughness. Conclusion: Although the degree of discoloration of the composite resin surface differed greatly between the coffee and red wine stained specimens, it did not differ with varying degree of surface roughness among specimens stained with the same pigment.

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Purpose: In recent years, the prevalence of dental caries in children has been decreasing in developed countries. From the National Survey of Oral Health, the number of DMFT at age 12 was 1.4 at 2011. However, caries prevalence increases with age, with a DMFT of 3.2 for 15- to 19-year-olds, 5.9 for 20- to 24-year-olds, and 8.5 for 25- to 29-year-olds. The purpose of this study was to focus on the cariogenic bacteria count in saliva using real-time PCR and examine to DMFT in junior and senior high school students (aged 12-13 and 15-16 years, respectively). The relationship between bacterial count and decayed/missing/filled teeth (DMFT) was investigated. Methods: The subjects were 596 children who were first-year middle school students or first-year high school students. To measure the cariogenic bacteria count in saliva, students were asked to chew unflavored paraffin gum for the collection of stimulated saliva during an oral health examination. Streptococcus mutans and Streptococcus sobrinus in 1 ml of saliva were measured using real-time PCR. Dental examinations were performed by 8 dentists. Results: In the group aged 12-13 years (262 students), S. mutans was below the detection limit (<10³ cells/ml) in 25.6% (67 students). In contrast, S. mutans was >10⁵ cells/ml in 17.9% (47 students). S. sobrinus was below the detection limit in 94.7% (248 students) and >10⁵ cells/ml in 1.1% (3 students). In the group aged 15-16 years (334 students), S. mutans was below the detection limit in 23.4% (78 students). In contrast, S. mutans was >10⁵ cells/ml in 20.7% (69 students). S. sobrinus was below the detection limit in 90.1% (301 students) and >10⁵ cells/ml in 1.8% (6 students). The mean number of DMFT was 0.9 in the group aged 12-13 years and 1.8 in the group aged 15-16 years. With regard to the relationship between the two bacterial species and DMFT, in all of the subjects a clear and statistically significant difference in the number of DMFT was seen between the group with S. mutans only and the group with neither of the two bacterial species. Conclusion: In the group aged 12-13 years, and 15-16 years, a clear, statistically significant difference in the number of DMFT was seen between the group with S. mutans only and the group with neither of the two bacterial species.

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Purpose: Emdogain® (EMD) is derived from the tooth germ of juvenile swine, and is commonly used for periodontal tissue regeneration, including the formation of alveolar bone, in the treatment of periodontitis. However, because it originates from pig tissue, some patients choose not to be treated with EMD. The active component of EMD is a peptide sequence that corresponds to one of the pro-proteins as amelogenin II. Angiogenesis is one of the most critical events in the wound healing process and in periodontal regeneration. As such, this peptide may function as an angiogenic factor to stimulate cell differentiation and tissue regeneration. Methods: We characterized the effects of 100 ng/ml of synthetic peptide by using matrix-assisted laser-desorption ionization time-of-flight mass spectrometry analysis of eosinophilic round bodies formed after subcutaneous injection of EMD into the backs of rats in a previous study on the proliferation after stimulation for 30 min or 1, 3, 6, 24 and 72 h, migration after stimulation for 1, 3 and 8 h, outgrowth extension after stimulation for 6 days, and ICAM-1 expression after stimulation for 3 days, in human microvascular endothelial cells (HMVECs). Results: We demonstrated that the EMD-derived peptide significantly increased HMVEC proliferation and chemotaxis over unstimulated controls after all stimulation times. The peptide also led to an increase in outgrowth of processes from HMVEC spheroids in three-dimensional collagen cultures. ICAM-1 mRNA expression was also significantly elevated in HMVECs following treatment with the EMD-derived peptide. Conclusion: EMD-derived synthetic peptide may act as an angiogenic factor to stimulate the proliferation, chemotaxis, adhesion and migration of microvascular endothelial cells.

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