The acidic monomers utilized in all-in-one adhesives play a key role in the enamel and dentin bonding performance. The purpose of this study is to investigate the mechanism by which 10-methacryloyloxydecyl dihydrogen phosphate (MDP) demineralizes the enamel and dentin surfaces prepared by a diamond bur in three types of experimental MDP-based all-in-one (EX) adhesives containing different amounts of water (46.6, 93.2 and 208.1 mg/g). The enamel and dentin reactants of EX adhesives were analyzed using solidstate phosphorous-31 nuclear magnetic resonance and X-ray diffraction. Increased amount of water led to increases in the efficacy by which MDP demineralizes the enamel and dentin surfaces. However, the rate of calcium salts of MDP produced slowed down at the water concentrations above 93.2 mg/g. The dentin yielded greater amounts of di-calcium salts of the MDP monomer and dimer than the enamel, which develops a different type of layered structure of MDP from the enamel.

we surveyed new patients examined in the Department of Operative Dentistry between April 1, 2019 and March 31, 2020. The following six items were extracted from the patients' electronic dental records: referral (yes/no) , sex, age, residence, chief complaint, and site of chief complaint. Patients were subsequently divided into groups according to referral status for comparison of the other items. To identify factors associated with referrals, we performed logistic regression analysis with referral as the dependent variable and sex, address, age, chief complaint, and site as independent variables; odds ratios and 95% confidence intervals were calculated for each variable. Odds ratios were high for age, site, chief complaint, and sex and yielded the following conclusions concerning these variables. Regarding age, most patients in the referral group were in their 40s and 50s, while most patients in the nonreferral group were in their 60s and 70s. The majority of new patients were female, while the percentage of male patients was slightly higher in the referral group than in the nonreferral group. The most common sites were the molars in both groups. The most common chief complaints in the referral group and the nonreferral group were apical periodontitis and class 2 caries, respectively. These results suggested that compared with the nonreferral group, patients in the referral group were younger, were diagnosed earlier, and visited our hospital with greater expectation of dental preservation through highquality treatment.