With the global development of the research of medicine,more and more new drug safety evaluation institutions have been certified by Good Laboratory Practices (GLP) and Association for Assessment and Accreditation of Laboratory Animal Care International (AAALACi).Laboratory animal,which is the carrier of drug safety evaluation,its survival condition and animal welfare will directly effect the experimental results.Dealing with laboratory animal husbandry by scientific methods in two systems is the requirement to make sure the accuracy of experimental data of animal experiments.With the certification processes and practical experiences in two certification systems of Tianjin Institute of Pharmaceutical Research New Drug Evaluation Co.,Ltd.,also accompanied by experience exchangement with peers,the relationship of practices in two certification systems will be preliminarily discussed;Through strengthening the management of laboratory animal,it can help the institutions get the certificates.

Objective : To observe the clearance of smear layer on the root canal wall in different action time by scanning electron microscope (SEM), and to determine the optimal amount of time using sonically activated irrigation to wash root canal in clinic. Methods: Fifty-six ex vivo human anterior teeth with single straight root canal were selected. After routine mechanical preparation, they were divided into two experimental groups according to different irrigating agents: saline group and EDTA group. Each group was assisted by VDW sonic activation EDDY. The saline group was divided into three subgroups according to the irrigating time: 5 s, 30 s and 50 s; EDTA group was divided into six subgroups according to the irrigating time: 5 s, 10 s, 20 s, 30 s, 40 s and 50 s. The control group did not undergo root canal irrigation. After irrigation, the root was cut longitudinally. The smear layer of crown, middle and apical of root canal wall was observed by SEM. Results: After irrigating for 30 seconds, there was a significant difference between the normal saline group and the control group and the 5 second group (P<0.05), and there was no difference in the middle and apical part (P>0.05). After 50 seconds, there was a significant difference in the score of the smear layer between the apical area and the other groups (P<0.05). After irrigating for 5 seconds or 10 seconds in EDTA group, there was a significant difference between the scores of the crown and middle area of the root canal and the control group (P<0.05), and there was no significant difference in the apical area (P>0.05). There was a significant difference between the 20-40 second group and the first two groups (P<0.05). There was a significant difference between the 50 second group and the other groups (P<0.05). Comparing the cleaning effect on the smear layer after 50 seconds of irrigating between the two experimental groups, the whole root canal showed significant statistical difference (P<0.05). Conclusion The EDTA-assisted sonic activated device used for 50 seconds has the best cleaning effect.

Objective To investigate the accuracy and feasibility of shear wave elastography(SWE)combined with superb microvascular imaging(SMI)for the differential diagnosis of benign and malignant thyroid nodules.Methods A total of 190 patients with thyroid nodu-les detected in the Ultrasound Department of our hospital from January 2021 to December 2022 who underwent ultrasound-guided fine-needle aspiration biopsy or exhibited postoperative histopathological improvement were selected as the study subjects.Among them,a total of 224 thyroid nodules(74 benign and 150 malignant nodules)were detected,all of whom underwent thyroid ultrasonography,SWE,and SMI.The parameters related to the Young's modulus of the tissue as well as the condition of fine blood flow and perforating vessels were calculated.Using histopathological results as the gold standard to construct receiver operating characteristic(ROC)curves,observe the effectiveness of SWE combined with SMI in the differential diagnosis of thyroid nodules,and compare the efficacy of different examination methods in the diagnosis of thyroid nodules.Results There were significant differences in the internal composition,echo,margin,cal-cification,and aspect ratio between the benign and malignant thyroid nodules(all P<0.05);however,there was no significant difference in the average diameter of the benign and malignant nodules(P>0.05).There were statistically significant differences in maximum elas-ticity,mean elasticity,elasticity ratio,microvascular score,peak shear wave velocity,and average shear wave velocity between the benign and malignant thyroid nodules(all P<0.05).The ROC curve showed that the area under the curve of the maximum elastic value was the highest,while the optimal diagnostic threshold was 29.52 kPa.The optimal diagnostic threshold for the microvascular flow score was 2.3 points.In terms of diagnostic efficacy,SWE combined with SMI showed the highest sensitivity(94.67%)and specificity(94.59%).Conclusion SWE combined with SMI can further improve the diagnostic efficiency of benign and malignant thyroid nodules and achieve quantitative evaluation and dynamic observation of lesions,which has application and promotion value.

Secondary caries is one of the main reasons that affect the service life of the restoration. Compared with primary caries, secondary caries have some particularities in etiology, disease progression, clinical manifestation, clinical diagnosis, treatment and prevention. Starting from the above aspects, combined with the latest basic and clinical research on secondary caries, this paper summarizes and analyzes its pathogenesis and prevention strategies, which will lay a certain foundation for in-depth understanding of secondary caries and promoting its clinical prevention and treatment.

Endodontic infection control is crucial to successful root canal treatment. Irrigation is the key step in endodontic procedures, and the application of root canal irrigation and disinfection medications play an important role. How to enhance antibacterial effects and functions in removing tissues while maintaining biocompatibility is a hot topic in endodontics. Currently, insights to address this issue can be split into two categories: one, the modification or combination of conventional endodontic irrigation solutions, and two, the development of novel endodontic irrigation solutions with new technologies and materials, for instance, nanomaterials and natural exacts. However, conventional endodontic irrigation solutions, such as sodium hypochlorite and chlorhexidine, are still the first choice in clinical practice. Most novel endodontic irrigation solutions remain at the pre-clinical laboratory stage. Clinical research and relevant data are required to determine whether various methods can improve endodontic irrigation. From basic research to clinical application is the direction for advancing to the next stage. The present article focuses on research progress on endodontic irrigation, especially concerning its antibacterial mechanism, characteristics and efficacy, to provide a reference for future clinical translation.

Dysbiosis can cause microenvironmental dysregulation, which can further lead to local or systemic diseases, such as caries, inflammatory bowel disease, obesity, and diabetes. Dysbiosis is primarily manifested as the disturbance of metabolic processes and products. Arginine plays an important role in various metabolic processes and homeostasis of the microbial flora and the host. This study aims to explore the potential therapeutic value of arginine and its metabolism and homeostasis regulation in diseases associated with oral-intestinal dysbiosis. Host and microbial homeostasis can be restored by regulating the composition or function of host microbiota, and arginine has been found to exhibit significant clinical potential in restoring host microbiota composition and function. For example, arginine can reduce the risk of caries by regulating the relative abundance of Streptococcus mutans and Streptococcus sanguineus. Additionally, arginine metabolism may play a therapeutic role in inflammatory bowel disease and obesity by regulating the relative abundance of Firmicutes and Bacteroidetes. In addition, supplementation of arginine and its metabolite polyamine has clinical prospects in the treatment of diabetic patients with ketoacidosis. Although studies have demonstrated the therapeutic role of arginine in oral, intestinal, and metabolism-related diseases, the specific mechanism is yet to be explored. In addition, further research is required to determine the optimal clinical dosage of arginine that can maintain microbiota homeostasis without causing any side effects.