Objective: To investigate treatment strategies for chronic periapical periodontitis in prematurely erupted premolars and provide guidance for managing pulp and periapical diseases in young permanent teeth with immature roots. Methods: A regenerative endodontic procedure (REP) was performed on a prematurely erupted maxillary left first premolar (tooth 24) at Nolla stage Ⅶ with chronic apical periodontitis, following standardized protocols including root canal irrigation, disinfection, and coronal sealing. The case was followed up, and a literature review was conducted. Results: Clinical resolution of symptoms was observed on tooth 24, with sustained root development. After a 20-month follow-up, the tooth had restored biological function. Literature synthesis revealed that periapical infections in prematurely erupted permanent teeth predominently arise from pulp exposure and bacterial infection, with retrograde infection being rare. For young permanent teeth with necrotic pulp, regenerative endodontic procedures has been established as the treatment of choice to promote apical closure and root maturation. The critical steps of regenerative endodontic procedures include thorough disinfection, induced bleeding to form a fibrin scaffold, and coronal sealing to facilitate stem cell recruitment and differentiation. Conclusion Regenerative endodontic procedures represents an effective and viable treatment option for prematurely erupted young permanent teeth with chronic periapical periodontitis.

Objective To investigate the incidence of multiple disease coexistence in emergency department patients over 65 years old and its impact on the risk of death in hospital, so as to provide theoretical basis for reducing the risk of death in emergency department patients over 65 years old. Methods From January 2019 to January 2020, elderly patients over 65 years old who received emergency treatment in our hospital were selected as subjects to analyze the coexistence of multiple diseases. The information of current disease, blood pressure, blood glucose level and other potential influencing factors, as well as the incidence of hospitalization after emergency treatment were collected, and the factors influencing the risk of death in hospital were analyzed and discussed. Results During the study period, there were 1 195 patients over 65 years old, including 469 patients with multi-disease coexistence (excluding malignant tumors), with an incidence rate of 39.25%. Among the elderly patients in the emergency department, the top four diseases with multiple coexisting diseases are as follows: ischemic stroke (43.92%), acute myocardial infarction (24.95%), hemorrhagic stroke (16.84%), and falls (11.30%). In addition, ^“ischemic stroke + hypertension + diabetes + coronary heart disease^” accounted for the highest proportion (42.22%) in the combination of multi-disease coexisting diseases, followed by "myocardial infarction + ischemic stroke + hypertension + Diabetes + coronary heart disease^” (21.11%), and the third in the composition ratio was ^“fall + ischemic stroke + hypertension + diabetes + coronary heart disease^” (0.66%). Among the 469 patients with multi-disease coexistence, a total of 68 died during hospitalization after emergency department; 469 patients were divided into two groups: the dead and the survivors, and the potential factors affecting the risk of death were analyzed. The multivariate regression analysis showed that male (OR=1.485 , P<0.001), age over 80 years (OR=3.090, P<0.05), more than four types of comorbidities (OR=4.407, P<0.001), BMI level showed weight loss (OR=4.366, P<0.001) and Comorbidities included hypertension (OR=3.564, P<0.001) as a potential risk factor, which would increase the risk of death; while normal blood pressure (OR=0.581, P<0.001) might potentially reduce the risk of death. Conclusion Special attention should be paid to the elderly patients over 65 years old who are male, over 80 years old, thin and with many types of comorbidities (more than four types), especially those with hypertension at the same time, in order to reduce hospitalization after emergency department risk of death during the period.