Purpose: The purpose of this study was to investigate the effects of a newly-developed glass ionomer cement containing zinc glass on the demineralization inhibition and the remineralization of root dentin for the treatment of root caries.

 Materials and Methods: Three chemical-set glass ionomer cements, ZIF-C10 (GC) containing zinc glass, Fuji VII (GC) and GlasIonomer FX ULTRA (Shofu), were set to the root dentin before or after the demineralization to evaluate the demineralized inhibition and remineralization effects. For the demineralization inhibition test, transmitted X-ray images were obtained by micro focus X-ray CT. Mineral profiles of root dentin up to 200 μm in depth were obtained from the images to analyze the mineral loss (vol %・μm). For the remineralization test, each material was filled in the pre-demineralized dentin cavity to simulate root caries. Cross-sectional images of the cavity after the remineralization for 60 days were taken using swept-source optical coherence tomography (SS-OCT). The area of interest near the cavosurface margin for 400 μm in width and 400 μm in depth was chosen to analyze the integrated intensity and attenuation coefficient of the SS-OCT signal. Image analysis was performed using ImageJ.

 Results: The results of the demineralization inhibition test showed a significant decrease of mineral loss for all the glass ionomer cements compared with the control. The amount of mineral loss for ZIF-C10 was significantly lower than those of the other glass ionomer materials (p<0.05). The SS-OCT signal of demineralized dentin after the remineralization test showed a significant decrease of integrated signal for ZIF-C10. The attenuation coefficient (μt) of SS-OCT signal intensity for ZIF-C10 was significantly lower than those of other materials (p<0.05).

 Conclusion: The results of this study suggest the superior demineralization inhibition and remineralization effects on root dentin of the newly-developed glass ionomer cement containing zinc glass.

 Purpose: Cone-beam computed tomography (CBCT) provides precise 3D images and cross-sectional images in any plane with a low radiation dose, allowing accurate diagnosis and treatment planning in endodontic practice. The purpose of this study was to investigate the current status of CBCT examinations at the endodontic clinic of Aichi Gakuin University Dental Hospital during 2015-2016.

 Methods: This study evaluated data from patients who attended the endodontic clinic during 2015-2016 and had CBCT scans taken. The endodontists who performed the CBCT examinations were asked to provide the following information about their patients: the number of cases, sex, age, tooth type, reasons for taking a CBCT image, findings, and treatment planning from the CBCT scan data.

 Results: A total of 237 CBCT examinations were performed: 78 in 2015 and 159 in 2016. The most common reasons for taking a CBCT image were to assess the relationship between the lesion and anatomic structures (16.4%: 2015, 17.8%: 2016), to assess the size and spread of a lesion (17.6%: 2015, 15.2%: 2016) and to detect apical periodontitis (10.1%: 2015, 12.0%: 2016). Valuable additional information such as the presence of cortical bone defects, sinus mucosal thickening, and thinning of root dentin were also obtained. Treatment planning based on the CBCT scan data resulted in some cases of termination of root canal treatment (46.3%: 2015, 50.3%: 2016) and extraction (23.8%: 2015, 11.7%: 2016).

 Conclusion: CBCT is effective in complex endodontic cases that are difficult to diagnose by conventional radiographic imaging. Further surveys will be carried out to determine the most appropriate use of CBCT in endodontic practice. It is also necessary for dental students, as well as clinicians, to be educated about the importance of training in CBCT image interpretation.

 Purpose: Calcium hydroxide preparations and mineral trioxide aggregate (MTA) are used as pulp-capping materials. However, these materials do not adhere to teeth and dental restorations. The purpose of this study was to develop a new adhesive pulp-capping material.

 Methods: In this study, the new pulp-capping material (PCX-TBB, Sun Medical, Tokyo, Japan) combined with 2-hydroxypropyl methacrylate and Portland cement, TheraCal LC (BISCO Dental Products, Schaumburg, IL, USA) and Dycal (Dentsply Sirona, York, PA, USA) were used. Discs of each material were immersed in distilled water, and the pH and calcium ion concentration were measured while exchanging water every 24, 48 and 72 hours. Next, human dental pulp-derived cells (DPCs: Dental Pulp Cells, AD010-F-RA, DV Biologics) were cultured with the discs in a 24-well plate. Then, the number of cells was measured after 24, 48 and 72 hours of culture. In addition, the dentin surfaces of 30 fresh bovine mandibular anterior teeth were used as the adhesion surface, and half of the dentin specimens were used as demineralized dentin. We cured each pulp-capping material on dentin, then performed shear bond strength tests on the bonded specimens.

 Results: The pH was over 10.5 in distilled water for all the pulp-capping materials. In addition, PCX-TBB and TheraCal LC showed significantly higher cumulative calcium ion release values than Dycal at all times, and after 72 hours PCX-TBB showed the highest value. As for the effect on cell proliferation, each pulp-capping material group showed a significantly lower cell number than the control group; the PCX-TBB group was second after the control group at 72 hours, and the cell numbers of the TheraCal LC and Dycal groups were significantly lower.

 PCX-TBB showed significantly higher shear bond strength than other materials under normal and demineralized dentin conditions. In addition, PCX-TBB and TheraCal LC showed significantly higher values for demineralized dentin than normal dentin. On the other hand, Dycal showed lower values for normal dentin and demineralized dentin.

 Conclusions: In this study, PCX-TBB had a pH as high as that of currently marketed pulp-capping materials, had a sustained release of calcium greater than that of current products, and exhibited adhesion to teeth. PCX-TBB was shown to be an adhesive pulp-capping material.