Purpose: Root canal shaping by nickel-titanium (Ni-Ti) is one of the most important steps in creating a glide path. However, it is not easy to control the original canal shaping by a manual glide path. The ProGlider single-file system (Dentsply Maillefer, Switzerland) was recently introduced for performing a mechanical glide path. This study was designed to analyze the shaping ability by ProGlider, and also evaluate the influence of canal shaping with WaveOne (Dentsply Maillefer) and ProTaper Next (Dentsply Maillefer) after shaping the glide path.
 Methods: Sixty Endo Training block canals (Dentsply Maillefer) were used, divided according to the glide path system and Ni-Ti rotary system used for canal preparation into 6 groups of 10 samples each: K-file, ProGlider, K-file & WaveOne, ProGlider & WaveOne, K-file & ProTaper Next, ProGlider & ProTaper Next groups. Canal transportations were assessed by comparing the pre-instrumentation and post-instrumentation images under an Olympus ZX16 with DP71 digital camera, and the superimposed images were analyzed using WinROOF. Data were statistically analyzed with the significance level set at p<0.05.
 Results: The glide path of ProGlider exhibited a significantly lower mean of canal transportation than manual K-File. It was shown that significantly lower deviation occurred by ProGlider & WaveOne than K-file & WaveOne. There was no significant difference between the K-file & ProTaper Next and ProGlider & ProTaper Next groups in canal transportation (p<0.05).
 Conclusions: This study confirmed the ability of ProGlider to reduce transportation, and the WaveOne and ProTaper Next Ni-Ti system can yield better performance with fewer problems compared with instrumentation performed with K-file.

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 Purpose: In this study, the interaction between the acidic monomer MDP employed in G-BOND PLUS (G-BP) and enamel or dentin was examined in detail by comparing the changes in the carbon 13 nuclear magnetic resonance (¹³C NMR) spectrum obtained before and after reaction with enamel and dentin particles using a solid-state and liquid-state carbon ¹³C NMR technique, to obtain information on the byproducts produced by enamel and dentinal decalcification. The effect of the demineralization ratio of tooth apatite by acidic monomer MDP on the shear bond strength to enamel and dentin was also examined.
 Methods: Bovine crown enamel particles or bovine crown dentin particles of 0.200 g were suspended in 1.000 g of G-BP, and the suspensions were vibrated for 10, 20, 60, 1,800, or 3,600 seconds. After centrifuging these suspensions, liquid-state ¹³C NMR spectra of the supernatant solution of G-BP were observed using an EX270 spectrometer. The ratio of intensity of the NMR peak of the vinyl methylene carbon for acidic monomer MDP employed in G-BP to the NMR peak of that for TEGDMA detected in the ¹³C NMR spectrum was determined before and after reaction with enamel or dentin particles. The reduction in the peak intensity for MDP was determined by dividing the difference in the intensity ratio obtained before and after reaction by the intensity ratio obtained before reaction. The reduction was determined as the ratio of demineralization of tooth apatite by MDP. Furthermore, the bond strength of G-BP to ground enamel and dentin was measured.
 Results: When the enamel or the dentin interfaced to G-BP, the intensity of the NMR peak that assigned to a vinyl methylene group of MDP was decreased. The reaction of 3,600 seconds later, the enamel was demineralized 66.50%, the dentin was demineralized 89.50%. Ca salt precipitated from reaction residual substance of G-BP and tooth substance apatite was found. If the reaction time of G-BP became longer time, increases in the amount of MDP increased the relative intensity amount of MDP-Ca salt the relative intensity ratio of NMR peak “g1” to the NMR peak “g2”. The demineralized ratio increased that until reacted with 20 seconds, and the bond strength increased for it slightly. However, later than 60 seconds of reaction, the bond strength of enamel was 15.53 MPa, and those of dentin was 10.39 MPa.
 Conclusions: The amount of demineralization of MDP in dentin was higher than that of enamel. The bond strength to tooth apatite showed that the bond strength to enamel was higher than to dentin.

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 Purpose: It is still unclear how inflammatory stimuli influence the kinetics and gene-expression profiles of stem cells. In this study, we focused on CD146, a marker of stem cell differentiation, and aimed to analyze the effect of lipopolysaccharide (LPS) stimulation on CD146 mRNA expression in stem cells from human exfoliated deciduous teeth (SHED) and rat bone marrow mesenchymal stem cells (RBMMSC) in vitro. We also analyzed the level of CD146 mRNA expression in LPS-stimulated rat incisor pulp tissues in vivo.
 Materials and Methods: SHED and RBMMSC were seeded, and cultured for 3, 12, and 24 hours in the presence of LPS (final concentration 10 ng/ml) or saline (control). After the given period, total RNA was extracted from the samples and CD146 expression was analyzed semi-quantitatively by reverse transcription polymerase chain reaction (RT-PCR). For in vivo analysis, male Wistar rats were anesthetized, the crowns of their lower incisors were cut off horizontally, and the pulp chamber was enlarged at 5 mm in length with K-files. Then, 1 μl of LPS (1 mg/ml) was applied and the cavities were sealed. At 3, 12, and 24 hours after the LPS stimulation, the pulp tissues were retrieved, total RNA was extracted, and RT-PCR analysis was performed in the same way as mentioned above.
 Results: After the LPS stimulation, CD146 mRNA expression was significantly upregulated in SHED at 12 and 24h, and in RBMMSC at 24h. In the rat incisor pulp tissue, CD146 mRNA expression was significantly upregulated at 3h after LPS stimulation.
 Conclusion: LPS stimulation significantly upregulated the expression of CD146 mRNA in SHED, RBMMSC, and rat incisor pulp tissues.

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 Purpose: Dentin hypersensitivity is characterized by short sharp pain arising from exposed dentin in response to various external stimuli. The stimuli cause the flow of dentinal fluid in dentinal tubules and trigger a painful sensation. To prevent pain from dentin hypersensitivity, it is suggested that either suppressing the nerve impulse or occluding the dentin tubules is effective. Zinc stearate has the ability to form a coating film. So we hypothesized that this compound could cover the dentin surface and prevent dentin hypersensitivity. The objective of this study is to evaluate the ability of this compound to seal human dentinal tubules, and to analyze the behavior of the compound in the dentinal tubules and on the dentin surface.
 Materials and Methods: Human normal molars or premolars were collected and the dentin samples were obtained from these teeth (n=120). The samples were randomly divided into 3 groups: the zinc stearate dispersion liquid group as an experimental group (Zn-St, n=40) ; the aluminum lactate/disodium hydrogen phosphate solution group as a positive control group (Al-PO₃, n=40) ; and the sorbitol solution group as a negative control group (Cont, n=40). All samples were brushed on the oral cavity side of the dentin samples by toothbrushes using zinc stearate dispersion liquid, aluminum lactate/disodium hydrogen phosphate solution, or sorbitol solution. The dynamics of each sample on the dentin surface and in the dentinal tubules were evaluated with a scanning electron microscope (SEM). Brushing was carried out every 6 hours in a day. The dentin samples were collected just after first brushing, before and after second brushing, before and after third brushing, and 24 and 36 hours after first brushing. At all times, dentin samples were set in the simulated oral cavity environments, which were reproduced the pulpal pressure and body motion in 37 degree saline.
 Results: In the Zn-St group, the dentin surface was coated and the dentinal tubules were occluded. Also, there was zinc stearate in the dentinal tubules just after brushing. In the Al-PO₃ group, there was deposition along with the dentinal tubules. In the Cont group, there was no change on the dentin surface or in the dentinal tubules.
 Conclusion: Zinc stearate could cover the dentin surface and enter into the dentinal tubules by consecutive brushing. We suggest that zinc stearate would be useful as a dentin hypersensitivity treatment.

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 Purpose: Dentin hypersensitivity is due to exposure of dentinal tubules, which occur through a hard tissue defect and/or gingival recession. The dentinal tubules located on the affected area tend to be larger in number and size than those on the unaffected area. In the current study, toothpaste containing zinc stearate was administrated to the patients with dentin hypersensitivity and the efficacy of the zinc stearate, which could occlude dentinal tubules as reported in previous study in vitro, was examined.
 Methods: Twenty five patients were recruited as subjects at the Tsurumi University Dental Hospital. The hypersensitive status of the subjects was distributed between grade 2 and 3 according to the Schiff Air Index. The subjects were divided randomly into the experimental group and the control group. The former group was given the toothpaste containing potassium nitrate and zinc stearate, whereas the latter was given the toothpaste without zinc stearate. The subjects of both groups were instructed to brush their teeth more than twice a day in the usual way. The affected sites of the subjects in both groups were blown with air of 18°C and 0.3 MPa before the use of the toothpaste, after 2 weeks and 4 weeks from the beginning of the trial. The visual analogue scale (VAS) to evaluate hypersensitive status was measured at every evaluation point. The effect of toothpaste was statistically analyzed by SPSS version 22.
 Results: The VAS values of both groups showed sequentially significant reduction. Although there was no significant difference in the VAS values between both groups at the baseline and 2 weeks after administration of the toothpaste, the VAS value of the experimental group reduced significantly compared to that of the control group after 4 weeks.
 Conclusion: This study suggested that the toothpaste containing zinc stearate relieved discomfort from dentin hypersensitivity in longitudinal administration.

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 Purpose: Due to their accessibility to periodontal pockets, manual toothbrushes with extra-fine bristles are fairly effective in plaque control. However, sonic wave toothbrushes seem to be more effective owing to their vibratory action. In the present study, we examined the effect of sonic wave toothbrushes with extra-fine bristles on plaque removal, change of flora within the periodontal pocket and gingival injury.
 Methods: Fifty-two patients with gingivitis or slight periodontitis were divided into four different groups. Three different varieties of sonic wave toothbrushes (based on the kind of extra-fine bristles) and one manual toothbrush with extra-fine bristles were used.
 Gingival injury, volume of gingival crevicular fluid, pocket depth, bleeding on probing, gingival index, and plaque control record were examined at 0, 2, and 4 week time points. Bacterial counts in the periodontal pockets were measured before and after toothbrushing using the polymerase chain reaction-Invader method.
 Results: All toothbrushes were found to exert little gingival injury. No significant differences in plaque removal or gingival inflammatory improvement were observed between each toothbrush. However, a significant decrease in periodontal pathogens was noted with the sonic wave toothbrushes with extra-fine bristles of 3 mm.
 Conclusion: Our results indicate that the extra-fine bristles of the sonic wave toothbrush are effective for plaque control in the periodontal pocket. Furthermore, they do not cause gingival injury and are safe for use in the oral cavity.

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 Purpose: It is considered that a sonic wave toothbrush can remove plaque from periodontal pockets owing to its brushing action and high vibration. However, it is difficult to effectively remove plaque from the deeper areas of periodontal pockets, even though it is extremely important to control pathogens in periodontal pockets. Therefore, we examined the effect of a combination of water jet and sonic wave toothbrush on bacteria in periodontal pockets.
 Method: We randomly divided 18 patients with periodontal pockets of 4-5 mm into two groups. In the test group, the subjects brushed their teeth with sonic wave toothbrushes from the buccal side and tongue palatal side for 10 s and then used a water jet for 10 s. Bacterial samples were collected before and after this procedure. We collected bacterial samples from a control group after the patients brushed with a sonic wave toothbrush and gargled. Quantitative and qualitative analyses were carried out using the polymerase chain reaction (PCR)-Invader method.
 Results: There were no significant differences in the number of pathogens found individually in the periodontal pockets. However, when evaluated overall, there was a significant decrease in the number of pathogens in the periodontal pockets after treatment in the test group. There was an approximately 4-fold increase in the removal effect, leading to a larger decline in the number of pathogens in the periodontal pockets of the test group than those in the control group.
 Conclusion: We consider that the combination of liquid flow force through the sonic wave toothbrush and the bubble water flow through the water jet was effective for removing the pathogens from the periodontal pockets.

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 Purpose: A new salivary multi-test system (AL-55) has been developed to check dental caries, periodontal disease and oral cleanliness. This test system can simultaneously assay seven saliva analytes for five minutes measuring color changes of the test strip as reflectance: [Dental caries] cariogenic bacteria, pH, buffer capacity, [Periodontal disease] blood, leukocyte, protein, [Oral cleanliness] ammonia. Our previous study demonstrated the clinical usefulness of AL-55 by investigating the correlation between oral conditions and reflectance measured by this system. While AL-55 can measure seven saliva analytes simultaneously, there are various standards measuring methods for saliva analytes such as cultivation, electrode or enzyme methods. This study was designed to examine the validity and reliability of AL-55 by evaluating correlation and concordance rates between test results measured by the standard methods and AL-55.
 Methods: Oral rinse samples (3 ml of distilled water, 10 sec rinse) were collected from 231 volunteer adults of the previous study. Ten μl of the sample was dropped on each pad of the strip, and the reflectance was measured after 1 and 5 min. The reference values were also measured by the following standard methods: [cariogenic bacteria] cultivation method, [pH, buffer capacity] pH electrode, [blood, leukocyte] latex immune agglutination turbidimetry, [protein] pyrogallol red method, [ammonia] glutamate dehydrogenase method. The correlation between the reflectance and the reference value was assessed with the Pearson correlation test (p<0.01). In addition, the results from standard methods and AL-55 were stratified into 3 groups (high, middle and low) and the concordance rates between them were calculated.
 Results: The reflectance of each analyte pad was significantly correlated with the reference value (p<0.01). The correlation coefficients were 0.59 (cariogenic bacteria), −0.74 (pH), −0.86 (buffer capacity), −0.74 (blood), −0.67 (leukocyte), −0.75 (protein) and −0.89 (ammonia). The concordance rates between the stratified measured values of the standard methods and AL-55 (high, middle and low) were 70% (cariogenic bacteria), 82% (pH), 73% (buffer capacity), 71% (blood), 72% (leukocyte), 84% (protein) and 90% (ammonia).
 Conclusion: This particular study revealed that the reflectance measured by AL-55 was highly correlated with the reference values measured by the standard methods and that the concordance rates between them were from 70% to 90%, leading to high validity and reliability of AL-55.

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 Purpose: The aim of this study was to evaluate by multi-channel electrocardiograph (Dream ECG) the occurrence of fatal arrhythmia in patients with an implanted cardiac heart device during root canal treatment using an electronic apex locator and/or ultrasonic irrigation.
 Materials and Methods: In this study, we observed two patients, one with an implanted cardiac pacemaker (PM) and the other with a cardioverter defibrillator (ICD), who underwent root canal treatment using an apex locator and/or ultrasonic irrigation. Before dental treatment, a cardiologist and dental anesthesiologist asked the patients detailed questions and confirmed the absence of the following within the last four weeks: inappropriate ICD shock: fatal arrhythmia; myocardial ischemia; and congestive heart failure (NYHA Ⅲ or above). In the case of complications, a cardiologist and dental anesthesiologist observed the patients during dental treatment, and prepared emergency medicine and an AED at the chairside. In Case 1, a 54-year-old male patient had a prior myocardial infarction, ventricular fibrillation, and an implanted ICD. His dental diagnosis was chronic apical periodontitis of the lower left first molar. In Case 2, an 80-year-old female patient had severe aortic stenosis, sick sinus syndrome, and an implanted pacemaker. Her dental diagnosis was chronic apical periodontitis of the upper left first molar. In these cases, an apex locator (RootZX; Morita) and/or ultrasonic irrigation device (OSADA Enac 10W; Osada) were used during the root canal treatment.
 Results: In these cases, slight noise was observed by Dream ECG. However, no significant lethal arrhythmia was observed during dental treatment of the patients by Dream ECG.
 Conclusion: The results suggest the possibility of providing safe dental treatment to patients with an implanted PM or ICD by carefully asking detailed questions and confirming stable heart condition in the past four weeks, as well as by monitoring by Dream ECG.

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