Evaluation of the root dentin bond strength and intratubular biomineralization of a premixed calcium aluminate-based hydraulic bioceramic endodontic sealer.

PURPOSE: This study evaluated the dentin bonding strength and biomineralization effect of a recently developed premixed calcium aluminate-based endodontic sealer (Dia-Root Bio Sealer) in comparison with existing calcium silicate-based sealers. METHODS: The root canals of 80 mandibular premolars were filled with Dia-Root Bio Sealer, Endoseal MTA, EndoSequence BC Sealer, and AH Plus Bioceramic Sealer. Medial and apical specimens were then obtained by sectioning. The push-out bond strength was measured using the medial specimens, and the failure mode was recorded. Intratubular biomineralization in the apical specimens was analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS). The data were analyzed using one-way analysis of variance followed by the Tukey test (P < 0.05). RESULTS: The push-out bond strength of Dia-Root Bio Sealer was significantly higher than that of the other tested materials, and a cohesive failure pattern was observed in all groups. Dia-Root Bio Sealer also exhibited a significantly higher degree of biomineralization than the other groups, and EDS analysis indicated that the biomineralized precipitates were amorphous calcium phosphate. CONCLUSION: The results of this study indicate that Dia-Root Bio Sealer has the potential to be used as an adequate root canal sealer due to its favorable bonding performance.

Research Note: Comparative evaluation of pathogenicity in SPF chicken between different subgroups of H5N6 high pathogenicity avian influenza viruses.

Since 2014, periodic outbreaks of high pathogenicity avian influenza (HPAI) caused by clade 2.3.4.4 H5 HPAI virus (HPAIV) have resulted in huge economic losses in the Korean poultry industry. During the winter season of 2016-2017, clade 2.3.4.4e H5N6 HPAIVs classified into 5 subgroups (C1-5) were introduced into South Korea. Interestingly, it was revealed that the subgroup C2 and C4 viruses were predominantly distributed throughout the country, whereas detection of the subgroup C3 viruses was confined in a specific local region. In the present study, we conducted comparative evaluation of the pathogenicity of viruses belonging to subgroups C2 and C3 (H15 and HN1 strains) in specific pathogen-free (SPF) chickens, and further compared them with previously determined pathogenicity of subgroup C4 (ES2 strain) virus. The HN1 strain showed lower viral replication in tissues, less transmissibility, and higher mean chicken lethal dose than the H15 and ES2 strains in SPF chickens. Considering that the HN1 strain has a different NS gene segment from the H15 and ES2 strains, the reassortment of the NS gene segment likely affects their infectivity and transmissibility in chickens. These findings emphasize the importance of monitoring the genetic characteristics and pathogenic features of HPAIVs to effectively control their outbreaks in the field.

[Effects of Nursing Work Environment on Intention to Stay of Hospital Nurses: A Two-Mediator Serial Mediation Effect of Career Motivation and Job-Esteem].

PURPOSE: This study aimed to identify the mediating effects of career motivation and job-esteem and the effect of the nursing work environment on intention to stay among hospital nurses. METHODS: Data were collected from 289 nurses working at an advanced general hospital. The research model design was based on the PROCESS macro proposed by Hayes and analyzed using SPSS 24.0 program. RESULTS: The results showed a positive correlation between intention to stay and nursing work environment (r = .19, p = .001), career motivation (r= .34, p < .001), and job-esteem (r = .37, p < .001). Nursing work environment (B = 0.34 [.09~.59]) and job-esteem (B = 0.27 [.04~.49]) had a direct effect on intention to stay. There was a two-mediator sereal mediation effect of career motivation and job-esteem. The nursing work environment showed a significant effect on the intention to stay among hospital nurses through career motivation and job-esteem. CONCLUSION: In order to increase the retention rate of hospital nurses, it is suggested that government and medical institutions provide multifaceted support that can increase nurses' motivation for career development and recognition of the nursing profession through improvement of the nursing work environment.