Purpose: In this study, teeth in which root canal shaping was performed with different apical limit settings were used to clarify the timing of development of apical dentinal microcracks (microcracks). The microcracks occurring during root canal shaping were observed using micro-computed tomography (micro-CT). Root canal obturation of the experimental teeth was followed by root-end resection and cavity preparation for the same teeth, and the occurrence of microcracks on the resected root surfaces was evaluated.

 Methods: Nineteen human-extracted mandibular canines and premolars with similar root morphology were used. Root planting models with exposed apex (test piece) were prepared for the teeth. Once a tooth was removed, micro-CT scanning was performed before the procedure. The apical limits were set in three groups (n＝6): at the anatomical apical foramen (Af), at 1 mm inner Af (Af−1), and at 1 mm outer Af (Af＋1). After root canal shaping with nickel-titanium rotary files under wetting, micro-CT scans were performed, and the presence of a microcrack was evaluated in each image. After root canal obturation, the apex was resected perpendicularly to the tooth axis using carbide burs at 3 mm from the apex. The resected root surfaces were stained with methylene blue solution, and stereomicroscopic observation was performed under light-emitting diode (LED) transillumination to record the occurrence and direction of microcracks. The length of microcracks from the root canal wall was also measured. Following these observations, 3 mm depth root-end cavities were prepared along the root canal axis using an ultrasonic tip. Subsequently, staining and transillumination observations were performed using the preview method, and the occurrence and direction of microcracks on the resected root surface were recorded. The length of microcracks from the wall of the root-end cavity was also measured.

 Results: Micro-CT images demonstrated no new microcracks during root canal shaping. After root-end resection, the number and length of microcracks increased in the order of the Af−1, Af and Af＋1 groups. After root-end cavity preparation, the detected incomplete cracks ran in the labiolingual direction and the complete crack ran in the mesiodistal direction. Furthermore, the length of microcracks after root-end cavity preparation was significantly greater in the Af＋1 group than in the Af−1 group (p＜0.05).

 Conclusion: The results suggest that root canal shaping with apical limit settings outside the root causes thinning of the dentin and increases the probability of microcracks during ultrasonic root-end cavity preparation.

 Purpose: It has been proposed that some enamel organ-derived cells undergo an epithelial-mesenchymal transition (EMT) during tooth development, differentiate into cementoblasts, and make acellular cementum. The primary purpose of this study was to elucidate the mechanisms of cell differentiation by transplanting apical bud-derived stem cells of the epithelial lineage of tooth embryos into the bony defects around the molars and tracking their dynamics. The secondary purpose of this study was to use those tissue stem cells as a source of cell transplantation for future periodontal tissue regeneration therapy.

 Methods: Apical bud cells from GFP-positive mouse incisors were isolated under a microscope, collected, dispersed, and transplanted into bone defects created around the molars of wild-type mice, and their dynamics were observed for three months. Undecalcified cryosections were made by Kawamoto’s method, and immunofluorescence staining was made using antibodies against Osteocalcin (OCN), Cementum protein 1 (CEMP1), and Cytokeratin 10 (CK10).

 Results: GFP-positive cells were observed to settle in the periodontal tissue after four weeks of transplantation. Most of the GFP-positive cells showed OCN positivity throughout the observation period. In 12 weeks, some transplanted cells were aligned along the surface of the cementum, and HE images showed the development of cement matrix-like structures around the cells. Among the transplanted cells, cells in the periodontal space were mostly CK10-positive and CEMP1-negative, while cells on the cementum and near alveolar bone were mostly CEMP1-positive and CK10-negative.

 Conclusion: Our observations revealed that some transplanted cells underwent EMT and became cementoblast-like on the root surface and osteoblast-like, where they were incorporated into the alveolar bone. Both cementoblast-like and osteoblast-like cells were CEMP1-positive. On the other hand, CEMP1-negative and CK10-positive cells were located in the middle of the periodontal ligament space, suggesting that they settled into the tissue as ERM without undergoing EMT. It is interesting to see how the transplanted cells migrate and settle or differentiate under the influence of surrounding cells. These results suggest that enamel organ-derived tissue stem cells may differentiate into osteoblasts and cementoblasts/cementocytes and could be the source of periodontal tissue regeneration.

 Purpose: Examination of the effectiveness of periodontal surgery for older people for which no solid evidence is available is important because the number of healthy, independent older patients is increasing annually. This study aimed to clarify the risk factors associated with the efficacy and prognosis of open flap debridement for older patients.

 Methods: Clinical data of 186 patients who underwent open flap debridement and were subsequently followed by supportive periodontal therapy (SPT) or maintenance for ＞5 years were retrospectively reviewed. Patients were divided into two groups according to age at the time of periodontal surgery: an adult group, aged 20-64 years and an older group, aged ≥65 years. Improvement, recurrence, and tooth loss were evaluated, and related risk factors were analyzed by multivariate logistic regression analysis.

 Results: The improvement of periodontal disease by open flap debridement in the older group was similar to that in the adult group, and no difference was found in the frequency of tooth loss in the 5 years after the start of SPT. However, the risk of recurrence at 5 years after the start of SPT was three times higher in the older group than in the adult group, suggesting that age is a risk factor for recurrence. In this study, no risk factors were specific to the older group other than age. This suggests that aggressive open flap debridement can be considered even in patients aged ≥65 years if there are no underlying diseases or compliance problems. However, the possibility of future hospital visits affected by health status and social background, presence of bleeding during probing, increase in pocket depth of ≥6 mm, and changes in the total periodontal inflamed surface area (total PISA), should be fully considered, and regular maintenance should be continued after surgical procedures.

 Conclusion: The results of open flap debridement in patients aged ≥65 years were comparable to those in patients aged ＜65 years. In older patients without underlying disease or compliance problems, open flap debridement should be actively considered. However, age is a risk factor for recurrence and regular postoperative management should be continued with attention to changes in clinical parameters.

 Purpose: Minimally invasive endodontics (MI Endo) has been advocated on the basis that minimal cutting of tooth substance prevents root fracture after endodontic therapy. The purpose of this study was to analyze the shaping ability of thermo-mechanically treated controlled memory (CM) wire nickel-titanium (NiTi) files using MI Endo.

 Methods: Using a J-shaped root canal model, ProTaper Gold (PTG) and ProTaper Ultimate (PTU) files made of CM wire were used in the experimental group, and ProTaper Universal (PT) files made of conventional NiTi wire were used in the control group, and their cutting properties were compared. The PTU, PTG, and PT groups were further classified into two subgroups (with and without straight line (SL) access), and the root canal width displacement and median displacement were compared between the six groups in total.

 Results: For the PTU and PTG groups, the root canal width displacement on the lateral side slightly increased at the 1 mm apical measurement, and there was a significant difference between the displacement on the inner and outer sides at 3-8 mm. However, in the PT control group, the displacement on the inner side increased at 3-5 mm, and the displacement on the outer side increased at 1 and 8 mm. We compared the root canal width displacement in the PTU, PTG, and PT groups between those with and without SL access, but no significant differences were observed. Comparison between the SL and no-SL PTU, PTG, and PT groups revealed no significant differences in root canal width displacement or median displacement at any of the measurement sites.

 Conclusions: PTU and PTG made with CM wire resulted in accurate root canal formation with no-SL access.

 Purpose: This study aimed to evaluate the influence of 37°C water immersion for up to 180 days on the discoloration of conventional resin composite cements and self-adhesive resin cements.

 Methods: Three conventional resin cements (Panavia V5, RelyX Ultimate, and Variolink Esthetic DC) and three self-adhesive resin cements (SA Luting Cement, RelyX Unicem 2, and SpeedCEM Plus) were examined in this study. Disk specimens (⌀15.0×1.0 mm) were fabricated using the cements and their colors were measured (CIELAB). The specimens were immersed in distilled water at 37°C for 180 days and the colors were repeatedly measured at 1, 7, 14, 21, 28, 90, and 180 days. The color differences (ΔE) were calculated for each measurement period. In addition, water sorption, water solubility, and surface free energy of the cements were measured. Data were analyzed using the Shapiro-Wilk test, Friedman’s test and Bonferroni corrections, and Mann-Whitney U-test.

 Results: All the cements except SA Luting Cement revealed clinically acceptable values of ΔE (＜3.3) at 90 days of immersion. ΔE of the cements remarkably increased after 90 days and showed values much greater than 3.3 at 180 days. All the self-adhesive resin cements demonstrated significantly greater values of water sorption than the corresponding conventional resin composite cements. As for water solubility, one of the three comparison pairs (Panavia V5 and SA Luting Cement) did not show a significant difference. The surface free energy was similar among the cements at approximately 50 mJ/m².

 Conclusions: Although the water sorption of the resin cements increased due to the presence of the adhesive monomers, the discoloration did not intensify as water absorption increased. The degree of discoloration was not related to the degree of water sorption.

 Purpose: Glide path preparation is one use of nickel-titanium (Ni-Ti) rotary files, but few studies have addressed the effectiveness of Ni-Ti hand files. In this study, we compared glide path preparation abilities between a Ni-Ti hand file and a Ni-Ti rotary file.

 Methods: One board-certified endodontist conducted glide path preparation in transparent root canal models. Observations of the state of root canal preparation, centering performance, and time taken to complete glide path preparation were compared between groups prepared using a Ni-Ti hand file (HandFlex; HF group) and a Ni-Ti rotary file (WaveOne Gold Glider; GG group).

 Results: Although both groups maintained the original root canal morphology during enlargement, the increase in root canal width was significantly greater in the HF group for both inner and outer sides (p＜0.05). Centering ratio at 1 mm from the apex differed significantly between HF and GG groups (p＜0.01). Glide path enlargement time was significantly shorter in the GG group (p＜0.05).

 Conclusion: Ni-Ti hand files took longer than Ni-Ti rotary files to achieve glide path enlargement, but maintained the original anatomy of the root canal in the same way.

 Purpose: The purpose of this study was to investigate the influence of additional insertion of the master apical file (MAF) after the file has reached its working length on root canal transportation and extrusion of the trial gutta-percha point out of the root apical foramen using five Ni-Ti rotary file systems with different bending properties.

 Methods: The cantilever bending test was used to measure the bending load of the MAF. The untreated J-shaped curved root canal model blocks were obtained, and the root canals were negotiated with a #10 stainless steel K-file. Root canal preparation was performed in five groups: ProTaper Gold (PTG), TruNatomy (TN), HyFlex EDM (HEDM), WaveOne Gold (WOG), and RECIPROC Blue (RCB) to around size 25 using X-smart IQ (n＝10). The post-preparation images were then obtained and superimposed on the pre-preparation images using image processing software. Additional insertions of MAF up to the working length were repeated ten, twenty, and thirty times for the post-preparation block, and the images were obtained and superimposed to measure the increase in the width diameter of the inner side and outer side. Gutta-percha points of the same size as the MAF of each group were inserted to the position of resistance of the root canal wall for each block. The length to the tip of the gutta-percha point was then measured using a digital microscope. The obtained values were statistically analyzed by the Kruskal-Wallis test with a significance level of 5%.

 Results: In all files, the bending load values increased linearly and then leveled off. After unloading, the values decreased, and except for TN, the bending load became zero during unloading. At 0-1.0 mm from the apex, transportation tended to occur on the outer side of the root canal, but at 2.0 mm and above, transportation tended to occur on the inner side. In the WOG and RCB groups, transportation to the inner side of the canal was observed at 2.0 mm. No gutta-percha point extrusion was observed in the final enlarged model, but the length of extrusion increased as the number of insertions increased.

 Conclusion: Additional insertion of the file caused root canal transportation inward above the root canal curvature and outward below the curvature, extending the apical reach of the gutta-percha point.

 Purpose: This clinical study aimed to evaluate whether changes were observed in saliva test outcomes before and after application of 38% silver diamine fluoride (SDF) in elderly patients with root caries lesions. Following this, the root caries discolored by SDF was restored to verify SDF as a potential caries indicator for the removal of carious tissue on root surfaces.

 Methods: This study was approved by the Research Ethics Committee of Asahi University, School of Dentistry (Approval Number: 32031). Twenty elderly patients with root caries visiting the Operative Dentistry Clinic of Asahi University Medical and Dental Center between March 2021 to March 2022 were recruited. The caries risk of these patients was evaluated using a saliva test kit (Salivary Multi Tests; SMT) before and after SDF application (at the first and the second visits). The values of SMT measurement before and after SDF application were analyzed for six items: cariogenic bacterial count, saliva acidity, buffering capacity, leukocytes, protein, and ammonia. Caries removal was guided by the staining from SDF as a caries indicator using an excavator, then a resin composite restoration was placed. Each clinical procedure was photographed.

 Results: There were 20 participants: 15 males and 5 females (mean age 76.5 years). The total number of teeth with root caries lesions was 90 (51 incisors, 23 premolars, and 16 molars). There were no significant differences in the SMT results before and after the SDF application (p＞0.05). However, the coefficient of variation values before and after SDF application tended to be different among the evaluated items. The coefficient of variation was 1.97 for caries-causing bacteria, while it ranged from 0.26 to 0.69 for the other items. From the photographs of the clinical cases, application of SDF discolored and arrested the root caries lesions. This led to a reduction in bacterial adherence as well as gingival inflammation. The resin composite restorations for the teeth with root caries lesions were deemed successful during the observation period (max. 10 months).

 Conclusion: No significant difference was found in each item of SMT measurement before and after the application of SDF. However, the bacterial count exhibited a significant variation, suggesting suppression of the bacterial adherence on the root caries lesion by the application of SDF. SDF application could be used as a favorable indicator for diagnosis and excavation of carious root tissue when a restoration is required.

 Purpose: Patients’ demand for dental esthetics has increased in recent years. Additionally, teeth bleaching can improve self-care and oral cavity awareness. However, bleaching is not permanent as the consumption of foods and drinks can cause re-discoloration of teeth. Tooth staining may be caused by drinks such as coffee, wine, and tea, and foods such as curry. However, the mechanism by which these substances cause staining has yet to be clarified. Therefore, in this study we examined the effects of colored food on the enamel surface by dietary pH changes.

 Methods: Extracted mandibular anterior bovine teeth were used as samples. The enamel samples were divided into four groups: turmeric (TM group), red pepper (RP group), tomato (TO group), and Milli-Q water (MQ group) as a control. The samples were immersed in 30 mL of solution for 3 hours in a 37°C incubator while being shaken. Color changes were measured before and after immersion. For colorimetry, L^＊, a^＊ and b^＊ in the CIE1976L^＊a^＊b^＊ color system were measured using a micro-area spectrophotometer, and ΔL^＊, Δa^＊, and Δb^＊ were obtained. Furthermore, the immersion solution was evaluated before and after immersion using a pH meter. A 3D laser microscope was used to measure the surface roughness of enamel.

 Results: The results revealed that the Δa^＊ value, which indicated redness, and the Δb^＊ value, which indicated yellowness, increased due to the influence of natural ingredients in the TM and RP groups. The various natural pigments in food, such as curcumin in the TM group and carotenoids in the RP group, are thought to be involved in the coloration. The enamel surface roughness of the TO group changed significantly before and after immersion. The pH of the TO group was 4.0, which was below the enamel critical pH of 5.5.

 Conclusion: The results of this study suggest that tooth staining of the enamel surface is affected by dietary pH changes.

 Purpose: This study aimed to evaluate the association between infection and hardness in root canal dentin by irradiating infected root canal dentin with blue light at a wavelength of approximately 405 nm.

 Methods: A total of 10 healthy human extracted teeth and 10 human extracted teeth with infected dentin were used as samples and semi-cut sections were prepared as longitudinal sections of the root canal. The root canal walls were observed using a stereo microscope under blue light at a wavelength of approximately 405 nm to measure the fluorescence spectrum and Vickers hardness. Subsequently, the area was observed using a scanning electron microscope.

 Results: In teeth with infected root canals, blue-light irradiation at a wavelength of approximately 405 nm induced fluorescence excitation at wavelengths of approximately 620 and 680 nm. In the healthy teeth, no significant difference was observed in Vickers hardness in the region with fluorescence excitation of up to 500 μm from the root canal wall; however, in the infected teeth, a significant decrease in Vickers hardness was observed in the region with fluorescence excitation of up to 500 μm from the root canal wall. Furthermore, in the infected teeth, a bacterium-like structure was observed via electron microscopy on the root canal wall surface, and in the dentin tubules in areas with fluorescence excitation, whereas in areas without fluorescence excitation, there were few bacterium-like structures.

 Conclusion: This study suggests that blue light of approximately 405-nm wavelength is useful in detecting infected areas in the root canal wall.

 Purpose: The aim of this study was to investigate the effect of temporary luting cement removal using a new 10-methacryloyloxydecyl dihydrogen phosphate (MDP) -based cleaner (KATANA Cleaner) on the dentin adhesion of a resin cement.

 Methods: Intact human dentin was ground with 600-grit SiC paper and divided into three groups. The first group was left untreated with the temporary cement (Con). For the other groups, dentin surfaces were covered with a temporary luting cement (Temporary Hard) and stored in water for one week. The temporary luting cement was removed using an ultrasonic scaler (US), and then treated with KATANA Cleaner for 10 s (KC). A resin composite block (KATANA Avencia Block) was bonded to the dentin using a resin cement (Panavia V5). The specimens were immersed in water for 24 h then cut into beams. These were subjected to thermal cycling stress for 0 cycles (TC0) or 5,000 cycles (TC5000). A microtensile bond strength test was performed at a crosshead speed of 1 mm/min. Data were statistically analyzed with two-way ANOVA and t-test with Bonferroni correction at a significance of 5%. The fractured specimens after debonding were examined using scanning electron microscopy and electron diffraction spectroscopy.

 Results: No significant differences were noted in microtensile bond strengths between Con-TC0 and KC-TC0, between KC-TC0 and KC-TC5000 and between Con-TC5000 and US-TC0. The temporary luting cement covered the dentin surface in the US group, and partially remained in the KC group. Energy-dispersive X-ray spectrometric analysis revealed a distinct Zn peak in the US group, while the peak was significantly decreased in the KC group.

 Conclusion: The combined method with an ultrasonic scaler and the MDP-based cleaner effectively removed temporary luting cement contaminants on dentin surfaces, thus securing durable bonding of a resin cement to dentin used for indirect restorations.

 Purpose: To evaluate the effect of single-shade resin composites on the color of porcelain laminate veneer (PLV) restorations comprising lithium disilicate (LDS) cemented to an underlying tooth of two different shades. The evaluation was carried out using the CIEDE2000 color-difference formula and a translucency parameter.

 Methods: Ceramic blocks (A2, HT, IPS e.max CAD, Ivoclar) of 1 mm thickness were fired and assumed to be PLV. Their adhered surfaces were polished with grit-silicon carbide paper (#1200), and their measurement surfaces were mirror-polished. Four resin composites were used as luting materials to fill the 50-μm space between the PLV and the 2-mm-thick standardized underlying tooth, which was then photo-polymerized to serve as the specimen. The following luting materials were used in the present study: single-shade GRACEFIL Universal LoFlo (GC), Clearfil Majesty ES Flow (Kuraray Noritake Dental), Omnichroma Flow (Tokuyama Dental), and A2 shade GRACEFIL LoFlo (GC). A2 and A4 resin composites (Filtek Supreme Ultra, 3M ESPE) polished with water-resistant polishing paper (#600) were assumed as the underlying tooth (underlying structure). Forty specimens were produced and immersed in distilled water at 37°C for 30 days. There were two conditions for the color of the underlying structure and four conditions for the luting material (n＝5). A Vitae Easy Shade V (VITA) digital spectrophotometer was used to determine the color of each specimen. The PLVs were investigated before and after cementation, and after immersion in water (Day 1, 3, 7, and 30) on the underlying structure. The data were analyzed using the 1976 CIEL^＊a^＊b^＊ color system and CIEDE2000 (ΔE₀₀). ΔE₀₀ was calculated for the underlying structure spacing and compared to a threshold considered acceptable in clinical practice (ΔE₀₀＞1.8). The translucency parameter (TP), determined by the color difference between the black and white backgrounds, was also evaluated. The statistical significance of each of the ΔE₀₀ and TP values at Day 30 was determined by the Shapiro-Wilk and Levene tests and one-way analysis of variance (ANOVA).

 Results: The one-way ANOVA results showed no significant differences in the ΔE₀₀ (p＝0.32) or TP (p＝0.23) values between the luting materials at Day 30. However, the ΔE value between the underlying structure of A2 and A4 exceeded the threshold value (ΔE₀₀＞1.8).

 Conclusion: The present study suggests that the color of the underlying tooth has more influence on the final color of the PLV restoration than the single-shade resin composite.

 Purpose: The purpose of this study was to evaluate the effects of the ProTaper Ultimate (PTU), which has a new design based on integrated technology, on preparation ability in simulated curved root canals compared with previous gold wire-based nickel titanium rotary file systems.

 Methods: The surfaces of J-shaped simulated root canals in clear resin blocks were scanned as image files. The working length was defined as the root canal length minus 1 mm. The negotiation of all root canals was confirmed with a stainless steel #10 K-file. The blocks were divided into three groups of 10 each (PTU, ProTaper Gold [PTG], and WaveOne Gold [WOG]) and randomly prepared through size #25. The inner and outer displacements of the root canal wall were measured from superimposed images before and after preparation. In addition, the working times of each group and process were measured. The Kruskal-Wallis test followed by the Steel-Dwass test were used for all comparisons and statistical analyses.

 Results: Regarding root canal wall displacement, no significant difference was observed in all groups at 1 mm and 2 mm from the root canal apex, except for 1 mm on the inner side of the curvature (p＜0.05). At 3 mm and 4 mm from the root canal apex, the root canal wall displacement of PTU was significantly smaller than those of PTG and WOG in the inner side of the curvature, while it was significantly larger in the outer side of the curvature (p＜0.05). PTU prepared the inner and outer sides most evenly among the three groups. The total working time and the root canal wall shaping time in each group were longer in the order of WOG＜PTU＜PTG. Both times were significantly different among the three groups (p＜0.01). In addition, PTU had the smallest variance and preparation took almost the same amount of time even when the experiment was performed multiple times. On the other hand, there was no significant difference between groups in the time required for glide path preparation.

 Conclusion: The curved root canals at the measurement points were prepared most evenly by PTU in this study. Also, the total working time and the root canal wall shaping time were significantly reduced with PTU compared to PTG, and both times of PTU were close to the measurement time of WOG.

 Purpose: Cellular energy metabolism by glucose plays an essential role in tissue wound healing. The use of 2-deoxy-D-glucose (2-DG) to suppress energy metabolism through the glycolytic system is similar to a low glucose environment. Therefore, the purpose of this study was to investigate the effect of 2-DG-induced reduction in glucose metabolism on cell viability.

 Methods: We examined the proliferation, migration, cytotoxicity, H₂O₂ production, glucose transporter type 1 expression, lactic acid production, and ATP synthesis after the intracellular uptake of three different concentrations of 2-DG into HGnFs.

 Results: 2-DG suppressed intracellular glucose metabolism, which led to a reduction in the cellular activity of human gingival fibroblasts (HGnFs). However, there were no changes in cytotoxicity or H₂O₂ production, and the effects on glucose metabolism were different from those in a low glucose environment.

 Conclusion: This study showed that the suppression of intracellular glucose metabolism in HGnFs by 2-DG may delay wound healing in periodontal tissues.

 Purpose: Cotton roll is widely used in dentistry for moisture control and isolation. However, cases of airway obstruction due to aspiration of the cotton roll have been reported, and some cases have even resulted in death. In this study, we developed an anti-aspiration gauze roll (AAGR) by attaching a thread to the gauze roll as an alternative to conventional cotton roll to prevent aspiration and forgetting to remove the cotton roll.

 Methods: A water absorption test was conducted to evaluate the anti-moisture ability. Three types of prototypes, large (300×30 mm), medium (250×30 mm), and small (150×30 mm), were prepared according to the size of gauze used. The length of the cotton yarn was 300 mm. An in vitro water absorption test was conducted in accordance with the test method stipulated in the standards for medical gauze and medical cotton established by the Japanese Ministry of Health, Labour, and Welfare to evaluate the moisture control ability of AAGR. Each specimen (n＝10) was immersed in 25°C distilled water for 3 minutes, left on a net for 1 minute, and weighed. For statistical analysis, one-way ANOVA was performed using statistical analysis software, followed by multiple comparison tests using the Tukey HSD test. The significance level was set at 5%. A clinical evaluation was conducted by surveying dentists about the usability of AAGR in clinical use. In the clinical evaluation, dentists were asked to use AAGR instead of cotton roll in clinical situations and complete a questionnaire. AAGR (large) was used for adult patients, and AAGR (small) was used for pediatric patients. The survey items included treatment details, water absorption capacity and speed, gauze portion size, gauze thread length and thickness, ease of use, and expectations for preventing aspiration.

 Results: In the water absorption test, there was a statistically significant difference in the amount of water absorbed among each group: the amount in descending order was AAGR (large), control group, AAGR (medium), and AAGR (small). In the questionnaire survey, the results for adults showed that all items were rated as equal to or better than the conventional cotton roll, but the results for children showed that there were areas for improvement regarding water absorption volume, water absorption speed, thickness, and ease of use.

 Conclusion: The results of the water absorption test showed that AAGR (large) absorbs more water than cotton roll and has superior moisture control ability. The use of AAGR is expected to prevent both forgetting to remove moisture control tools, and their accidental ingestion or aspiration.

 Purpose: To compare the shaping characteristics and ability of the JIZAI (JZ) Ni-Ti rotary file to two other Ni-Ti files that have a similar operating environment to JZ, HyFlex CM (HCM) and ProTaper Next (PTN).

 Methods: Root canal preparation was performed in a J-shaped canal model using the three file systems (n＝4), and dental cone-beam computed tomography (CBCT) was performed. The three-dimensional images were superimposed before and after instrumentation at the same position. The X-, Y-, and Z-axes were set 1 mm coronal to the root apex, and the cross-sectional morphology, the extent of transportation, and the volume of the shaped root canal wall were evaluated.

 Results: The cross-sectional morphology of the root canal was round, similar to the original root canal morphology with JZ and PTN. The HCM showed an elliptical tendency toward the sagittal direction. The transportation was relatively larger with JZ and smaller with HCM, with no significant difference between the files. The shaped root canal wall volume was greatest with HCM and least with JZ, with no significant difference between the files.

 Conclusion: JIZAI had equivalent shaping ability to HyFlex CM and ProTaper Next in terms of transportation and shaped root canal wall volume, and therefore might be useful for safe preparation of root canals.

 Purpose: Glucose metabolism plays a critical role in osteoblast differentiation and influences vital processes involved in bone formation and remodeling. This study explored the inhibitory effects of 2-deoxyglucose (2-DG) on glucose uptake by osteoblasts and its impact on cell differentiation.

 Methods: Based on the structural similarity between 2-DG and glucose, the effects of glucose metabolism on osteoblast differentiation were examined by competitive inhibition of glucose uptake. MC3T3-E1 (mouse osteoblast-like cells) were cultured in media containing 10% FBS supplemented with 2-DG to evaluate cell proliferation and osteogenic differentiation.

 Results: Inhibition of intracellular glucose metabolism by 2-DG inhibited MC3T3-E1 cell proliferation and mineralization. However, the gene expression of Runx2 mRNA was enhanced in the 2-DG group. Moreover, there was a negligible difference in the osteocalcin production.

 Conclusion: Decreased intracellular glucose metabolism inhibited osteoblast proliferation and differentiation.

 Minocycline hydrochloride ointment is applied to periodontal pockets to treat periodontal disease. We encountered a case of an immediate-type allergy to minocycline hydrochloride dental ointment, despite the absence of a history of allergies to antibiotics.

 Case report: The patient was a 72-year-old female, with no significant medical history. Systemic erythema and urticaria developed in June 2017. Similar symptoms occurred again in October and November 2017, for which she consulted for an internal medicine examination. However, the cause remained unknown. Because the symptoms always occurred after she received treatment for periodontal disease, we performed a prick test to diagnose any possible allergy caused by the materials used in her dental treatment. A positive reaction to the allergy test was reported for minocycline hydrochloride ointment. We informed her dentist and requested that periodontal maintenance treatment with minocycline hydrochloride ointment be ceased.

 Course: She has not exhibited any allergic symptoms since the application of minocycline hydrochloride ointment was stopped.

 Discussion: It was suspected that allergic symptoms could have developed during the course of periodontal maintenance treatment. Given that the incidence of allergic reactions is increasing, it is important to consider the possibility of allergic reactions to dental materials and medicaments.

 Conclusion: An incremental application of a small amount of topical dental antibiotics into the periodontal pocket can result in immediate-type allergic reaction.