Purpose: Oral malodor results primarily from the microbial metabolism of amino acids in local debris in the oral cavity. This study compared the oral malodor-reducing effects of the following tablet or lozenge products: 1) Rose Wind, which contains cetylpiridinium chloride (CPC), dipotassium glycyrrhizate, and platycodon fluid extract (Shionogi); 2) Protect Drop, which contains CPC (Tokiwa Yakuhin); and 3) Frisk, a mint-flavored tablet (Kracie Holdings). Rinsing mouth with water was used as control.
 Methods: The study was performed with 82 healthy student volunteers (mean age, 25.2±2.2 years). Of the participants, 57 who had oral malodor levels higher than 80 ppb as measured by a portable sulfide monitor were divided randomly into four groups: Rose Wind (n=15), Protect Drop (n=14), Frisk (n=14), and water-rinsed control (n=14). The oral malodor level, amount of salivary flow, salivary pH, salivary buffering capacity, and tongue moisture were examined before and after taking the products or rinsing with water.
 Results: Each of the products reduced oral malodor significantly. In particular, both types of lozenges reduced oral maldor to less than 100 ppb, which is defined as no bad breath. Concerning the clinical parameters, salivary pH was significantly increased in the Rose Wind group, the buffering capacity of saliva was significantly increased in the Protect Drop group, and the amount of salivary flow was significantly increased in the Frisk group. The Rose Wind group showed an increasing tendency in tongue moisture, but this trend was not statistically significant.
 Conclusion: Both of the lozenges tested showed excellent oral malodor-reducing effects. In addition, the three products examined in this study activated mouth functions.

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 Purpose: The influence of the dental tubule content on sealing of the dental tubule remains unknown, and further investigation is awaited. In the present study, a desensitizer was applied to dental tubule openings with the contents of the tooth immediately after extraction to morphologically investigate the sealing effect.
 Materials and Methods: Four different types of desensitizer were applied (MS Coat F, GLUMA Desensitizer, SHIELD FORCE PLUS, and FL-BONDⅡ) to third molars extracted in Asahi University Hospital.
 ・Contact angle and surface tension measurement: The dentin was polished until flat using #1,600 waterproof abrasive paper. Samples were then classified into two groups: one was dried under vacuum at 37℃ for 24 hours (D), and the other was immersed in distilled water (W) with 1μl of desensitizer. The contact angle was measured chronologically up to 60 seconds. Surface tension was measured chronologically up to 60 seconds using the hanging drop method with a drop of 1μl of desensitizer.
 ・Electron scanning microscope (SEM) imaging of the dentinal tubules and elemental analysis: The cervical area of the third molar immediately after extraction was segmented to expose the dentinal tubule openings. Samples with desensitizer applied within 30 minutes after extraction (30M) and those immersed in artificial saliva for 4 weeks (4W) were fixed with glutaraldehyde, and sealing of the dentinal tubules was observed morphologically. The Ca/P ratio was calculated using an energy dispersive X-ray fluorescence spectrometer. A significance test (ANOVA, Fisher’s PLSD test, p<0.05) was performed for all the values obtained.
 Results:
 ・Contact angle and surface tension: A significant difference was observed in the contact angle depending on the type of desensitizer. There was also a significant difference between D and W, and the contact angle was larger in W. Contact angles of W with GLUMA Desensitizer and SHIELD FORCE PLUS were small. A significant difference in the surface tension was observed depending on the type of desensitizer. Surface tensions in W with SHIELD FORCE PLUS and FL-BONDⅡ were small.
 ・SEM findings of the dentinal tubules and Ca/P molar ratio: In 30M, dentinal tubules of GLUMA Desensitizer remained open, and organic-like material was observed in the tubules, but disappeared in 4W. In the dentinal tubules of MS Coat F, microparticles and crystals were observed in 30M, but disappeared in 4W. In the dentinal tubules of SHIELD FORCE PLUS and FL-BONDⅡ, approximately 20μm of resin tag-like material was observed both in 30M and 4W, and dentinal tubules were sealed. Since the size of fillers contained in FL-BONDⅡ is larger than the tubules, some of them blocked the infiltration of resin into the tubules. Considering the Ca/P ratio near the dentinal tubule openings of 4W, there was no significant Ca deposition in all desensitizers.
 Conclusion: The desensitizers used in the present study showed poor wettability with wet dentin, suggesting that the infiltration of these desensitizers into the vital dentinal tubules is difficult considering the pulpal pressure. However, dentinal tubules of the samples with SHIELD FORCE PLUS were closed by forming approximately 20-μm resin tag-like materials in both samples immediately after extraction and 4 weeks after extraction.

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 Purpose: It was reported that low-energy laser ablation of dentin, which causes little pain, significantly reduced the resin bond because the superficial layer of lased dentin was mechanically weakened due to the formation of structural defects and a heat-denatured layer. It was also reported that the bonding performance of the resin-modified glass-ionomer cement (RMGI) to lased dentin was relatively stable compared to the bonding resin regardless of the power output. In this study, to develop a new dentin bonding system suitable for Er: YAG-lased dentin, the bonding performance of RMGI to dentin irradiated at various output powers was evaluated and compared with that of the bonding resin.
 Methods: Flat dentin surfaces from freshly-extracted bovine teeth were prepared and irradiated with Er: YAG (Erwin Adverl) laser at low power (50 mJ/1 pps, low-irradiation), medium power (150 mJ/1 pps, medium-irradiation), and low power followed by medium power (finishing-irradiation). These lased dentin and non-lased dentin were subjected to the following bonding procedures prior to the placement of the composite (Clearfil AP-X): G-Bond Plus (G group), Self-Conditioner/Fuji Lining Bond LC (FLB group), and Self-Conditioner/Fuji Lining LC (FL group). The micro-tensile bond strengths (μTBSs) and fractomorphology were evaluated (Dunnet’s multiple comparison and Fisher’s PLSD, p=0.05), and cross-sectional observation of the interface was conducted under SEM.
 Results: For the G group, the μTBSs to the lased dentin at any output power were significantly lower than those to the non-irradiated dentin (p<0.05). Most of the specimens demonstrated adhesive failure or mixed failure (dentin and bonding resin) and some cracks from the denatured layer in the lased dentin to the bonding resin. However, both the FLB and FL groups exhibited approximately the same μTBSs to the lased dentin of the medium- and finishing-irradiation, while those to the lased dentin of low-irradiation were relatively low in comparison with those to non-irradiated dentin (p<0.05). Mixed failure (RMGI and dentin) or cohesive failure in RMGI occurred, and good adaptation between the RMGI and lased dentin along with microcrack formation within RMGI was observed characteristically in both groups.
 Conclusion: The present findings revealed that RMGI might reduce strain concentration at the adhesive interface and exhibited relatively stable bonding performance to the laser-irradiated dentin, demonstrating the efficacy of RMGI as a possible dentin bonding system for Er: YAG-lased dentin.

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 Purpose: This study evaluated the influence of the surface treatment of glass-ionomer cement (GIC) on the bond strength of resin composite and surface-free energies.
 Methods: One conventional GIC (Fuji IX GP) and two resin modified (RM) GICs (Fuji II LC EM, Fuji Fill LC Flow) were used. The GICs were hand-mixed according to the manufacturers’ instructions, inserted into the mold and a transparent matrix was added to give a smooth surface. For RMGICs, specimens were light-irradiated for 20 s. Specimens were prepared and divided into three groups as follows: without pretreatment (control), 35% phosphoric acid etching for 10 s, and air-abrasion for 10 s. The adhesive was applied and resin composite was bonded according to the manufacturers’ instructions. The bonded specimens were stored for 24 hours in distilled water at 37℃. Ten specimens per group were tested in shear mode at a cross-head speed of 1.0 mm/min. The surface-free energies of five specimens per group were determined by measuring contact angles. Data for each adhesive system were analyzed using Tukey’s HSD test.
 Results: For conventional GIC, acid etching or air-abrasion increased the bond strength (8.7-9.2 MPa) when compared with the control (5.7 MPa); however, RMGIC resulted in significantly lower bond strengths (11.1-14.4 MPa) than in the control (16.4-21.2 MPa). The value of the γs^－component increased when conventional GIC was treated with phosphoric acid or air-abrasion (54.1-62.1 mN・m^－1) when compared with the control (53.2 mN・m^－1). For RMGICs, lower values of the γs^－component were detected for the control group (20.0-24.1 mN・m^－1), indicating the presence of a resin-rich layer on the surface.
 Conclusion: The results of this study showed that surface treatment of the conventional GIC promoted higher bond strength to resin composite, but decreased bond strengths for RMGICs. RMGIC surfaces should be left untreated to obtain optimal bonding to resin composite, due to similar chemistry between RMGIC and the resin composite which allows strong chemical bonding of RMGIC to the resin composite.

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 Purpose: A new dentin desensitizer,“Nanoseal” , can be easily applied without rubbing to produce a layer of nano-particles on dentin surfaces which occlude dentinal tubules and suppress hypersensitivity (Hys). The purpose of this study was to confirm the occlusion of dentinal tubules by using FE-SEM and to evaluate the clinical desensitizing ability of Nanoseal. A clinical evaluation was conducted one week after application by the criteria of not only sensitivity to cold air and scrubbing stimulation but also Hys symptoms in daily life.
 Materials and methods: Nanoseal was applied to 101 patients with Hys and rinsed off. Pain symptoms were evaluated before and after application. The effectiveness of desensitization was examined at the next appointment (after one week) by sensitivity to cold air, scrubbing stimulation and Hys symptoms during one week of daily life. An overall rating of effectiveness was determined by the changes in Present Pain Intensity (PPI) with a 6-grade scale in conjunction with the changes in Visual Analogue Scale (VAS) value.
 Results:
 A. Dentinal tubule occlusion
 Nanoseal produced a layer of nano-particles on the exposed dentin surface and occluded dentinal tubules even under difficult conditions such as contamination by blood or saliva, dilution with water, and shorter time (3-8 seconds) of application.
 B. Clinical evaluation
 1. Changes in VAS value: Preoperative mean value was 32.7±22.4 while postoperative mean value was 8.5±9.7. Pain symptoms were significantly improved (paired t-test: p<0.01).
 2. Changes in PPI: Preoperative mean score was 1.7±1.0 while postoperative mean score was 0.5±0.5. Pain symptoms were significantly improved (paired t-test: p<0.01).
 3. Effectiveness (efficacy) rating: 87 of the 101 cases (86.1%) showed desensitizing efficacy by application of Nanoseal.
 4. Safety and operability: No side effects were detected after application of Nanoseal. It was shown that Nanoseal can be easily applied to the gingival sulcus or the adjacent tooth surface, even when wetted by saliva or blood.
 Conclusion: These results suggest that Nanoseal showed excellent pain reduction effects, and is safe and useful in the treatment of daily Hys symptoms.

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 Purpose: Currently, zinc oxide eugenol-based sealer is widely used as a sealer and good results have been obtained. It has been reported that the sealer poses few clinically significant issues and has a low influence on the retentive strength of zinc oxide eugenol-based sealers, even when making a core build-up with fiber posts immediately after hardening. On the other hand, sealers that do not contain eugenol are also utilized due to concerns that this compound inhibits resin polymerization. Powder-liquid type zinc oxide non-eugenol-based sealer is widely used but it also has issues inherent to its powder-liquid formulation, such as its collection ratio and operability. In light of these issues, we developed a paste type non-eugenol-based sealer (CS-N), and compared it with a powder-liquid type zinc oxide non-eugenol-based sealer (Canals N).
 Methods: In this study, we conducted physical property tests according to ISO6876: 2012 on flow, working time, setting time, firm thickness, solubility and disintegration, and radio-opacity. We also conducted a survey of clinicians on clinical setting time, subjected the sealer to an apical sealing test, and assessed the impression of ease of paste dispensing and mixing.
 Results: In the ISO6876: 2012 physical property tests, the values for flow, working time, setting time, firm thickness, solubility and disintegration, and radio-opacity of CS-N were all appropriate for a sealer. Clinical setting time was approximately 12 minutes, the values for apical sealing ability of lateral condensation filling and heat-softened filling were similar to those of Canals N, and technicians’ impressions on using CS-N were good.
 Conclusion: Upon comparing the results with those of a commercially-available powder-liquid type zinc oxide non-eugenol-based sealer (Canals N), the results of tests according to ISO6876: 2012 were all appropriate for a sealer. The clinical setting time was approximately 12 minutes for the paste type non-eugenol-based sealer and 20-30 minutes for Canals N.
 CS-N is effective in preventing coronal leakage, and the values for apical sealing ability of lateral condensation filling and heat-softened filling were similar to those of Canals N.
 Clinicians’ impressions on using CS-N were good, with a favorable overall evaluation of the ease of using this paste-type sealer.
 This novel paste-type sealer CS-N is equivalent to Canals N in terms of apical sealing and each of the above-mentioned physical properties. Moreover, its clinical setting time of approximately 12 minutes showed that CS-N is effective in preventing coronal leakage, and the values for apical sealing ability of lateral condensation filling and heat-softened filling were similar to those of Canals N.

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 Purpose: The aim of this study was to compare the incidence of root cracks observed at the apex in the canal wall after canal instrumentation with two single reciprocating files (WaveOne and Reciproc), and a multiple rotary file (ProTaper).
 Methods: Forty maxillary premolars with two independent canals were selected. The teeth were divided into four groups (n=20) of 10 teeth with 20 canals according to the Ni-Ti rotary file type used: WaveOne (Dentsply Maillefer, Switzerland), Reciproc (VDW, Germany), and ProTaper (Dentsply Maillefer), and then instrumented with Glide (Dentsply Maillefer). The apical root surface and horizontal sections 1, 3, 5 mm from the apex were observed under a microscope. The presence of cracks was counted and the significance level was set at 0.05.
 Results: No cracks were found in the control. Root canal cracks were found in both the single reciprocating file (WaveOne and Reciproc) and multiple file (ProTaper) groups, but no significant difference was found in the total value of all cross sections (p>0.05). On the other hand, the number of root crack lines on the 1-mm cross section was significantly less than in the 3- and 5-mm sections in all experimental groups.
 Conclusions: Root canal preparation with both reciprocating and rotary file instruments resulted in root cracks at 1－5 mm from the apex, although there was no significant difference between the file systems.

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 Purpose: We previously reported that matrix metalloproteinase (MMP) -3 accelerates wound healing following dental pulp injury in rats. Additionally, we identified that a proinflammatory cytokine mixture (CM; interleukin-1β, tumor necrosis factor-α, and interferon-γ) induced MMP-3 activity in odontoblast-like cells derived from mouse embryonic stem cells, suggesting that MMP-3 plays a potentially unique role in wound healing and dental pulp regeneration in odontoblast-like cells. Here, we investigate whether upregulation of MMP-3 activity by CM regulates the proliferation and apoptosis of purified odontoblast-like cells derived from induced pluripotent stem (iPS) cells.
 Methods: The proportion of α2 integrin-positive cells in the total differentiated odontoblast-like cell population is a measure of the purity of the iPS cell-derived odontoblast-like cells, and was estimated by FACS analysis to be 98%. Reverse transcriptase polymerase chain reaction, western blotting, an MMP-3 activity assay, a BrdU cell proliferation enzyme-linked immunosorbent assay, and DNA fragmentation analysis were used to evaluate siRNA-mediated down-regulation of MMP-3 expression and activity, and any changes in the proliferative and apoptotic responses associated with this reduced expression.
 Results: Low concentrations of CM (1 or 3U) induced MMP-3 mRNA and protein expression, increasing MMP-3 activity and cell proliferation (p<.05), but not apoptosis. MMP-3 silencing produced a potent and significant suppression of cytokine-induced MMP-3 expression and activity, decreased cell proliferation and increased apoptosis (p<.05). These effects were restored by application of exogenous MMP-3 (p<.05).
 Conclusion: Current evidence suggests that low concentrations of CM induce an MMP-3-mediated increase in odontoblast-like cell proliferation, whereas higher concentrations (5U) inhibit cell proliferation and promote apoptosis. Our current data suggests that CM induces MMP-3-regulated cell proliferation and anti-apoptosis effects in odontoblast-like cells derived from iPS cells, in addition to well-documented destructive roles in inflammation.

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 Objective: Ozone which generates OH radicals may assist the resurgence of the medical use of OH radicals. Ozone water and ozone gel may inhibit the effectiveness of OH radicals as an antibacterial agent. The purpose of this study was to investigate the bactericidal effects of ozone gel at different concentrations against key oral pathogens and the cytotoxicity to adult human gingival and periodontal ligament fibroblasts (HGF and HPDL).
 Material and Method: Streptococcus mutans (ATCC25175), Streptococcus sanguinis (ATCC49296), Aggregatibacter actinomycetemcomitans (ATCC29522), and Porphyromonas gingivalis (W83, ATCC33277) were selected for the bactericidal tests. Each genus of bacteria was incubated with ozone gel for one minute at room temperature and their survival rates were measured by colony counting. HGF was obtained from the gingival tissue around extracted adult human teeth. Cytotoxicity of ozone gel against HGF and HPDL was studied by cell proliferation assessment with Alamar Blue assay.
 Results and Conclusion: The results demonstrated that ozone gel concentration exceeding 125 ppm had significant bactericidal effects on A. actinomycetemcomitans and P. gingivalis (W83, ATCC33277). Ozone gel concentration of 500 ppm had significant bactericidal effects on S. sanguinis, but not on S. mutans. Compared with glycerol, ozone gel concentration of over 50 ppm showed significant inhibition of HGF and HPDL proliferation. These results suggest that ozone gel has prominent bactericidal effects against periodontal pathogens.

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