Background and Objective Periodontal ligament‐associated protein‐1 (PLAP‐1) is an important regulator of osteogenic differentiation of periodontal ligament cells and plays important role in the homeostasis of periodontal tissues. But the role of PLAP‐1 in periodontitis is poorly understood. Expressions of PLAP‐1 in experimental periodontitis are observed to elucidate whether PLAP‐1 gets involved in the pathogenesis of periodontitis. Material and Methods Wistar rats were randomly allocated to two groups (n = 6/group): Ligation group and Control group. PLAP‐1 expression in experimental periodontitis was assessed by immunohistochemistry and collagen fibers in periodontal ligament were observed using picrosirius red staining. Expressions of PLAP‐1 and CD68 in periodontitis were colocalized by double‐labelled immunofluorescence. To further examine the relationship between PLAP‐1 and osteoclastogenesis in experimental periodontitis, acute periodontal inflammatory infiltration and alveolar bone destruction were induced by administering ligated rats with 10 ng/mL tumor necrosis factor alpha (TNF‐α; ligation + TNF‐α group, n = 6). Alveolar bone loss was observed by micro‐computed tomography (Micro‐CT), and osteoclasts were identified by tartrate‐resistant acid phosphatase staining (TRAP). Expressions of PLAP‐1 in TNF‐α stimulated human periodontal ligament cells were also detected at 24 and 48 hours by western blotting. Results PLAP‐1 expression levels in periodontal ligament cells and collagen fibers were lower in the ligation group,compared with the control group. Similarly, TNF‐α decreased PLAP‐1 expression in human periodontal ligament cells in vitro. Degradation or destruction of collagen fibers accompanied the reduced PLAP‐1 expression in the periodontal ligament in the ligation group. Colocalization of PLAP‐1 and CD68 revealed the positive relationship between PLAP‐1 and CD68+ infiltrating cells in periodontitis. More PLAP‐1‐positive inflammatory cells were found in the ligation + TNF‐α group, compared with the ligation + saline group. Conclusion PLAP‐1‐positive inflammatory cells are involved in the pathogenesis of periodontitis. An increase in PLAP‐1‐positive inflammatory cell number contributes periodontal inflammation and alveolar bone loss.

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Background: The aim of this study was to analyze the outcome and prognostic factors of root canal treatment (RCT) and endodontic microsurgery (EMS) in the treatment of apical periodontitis (AP), respectively, and to compare the outcome and prognostic factors between initial RCT and nonsurgical retreatment (re-RCT) for AP.Methods: Patients with AP were recruited from the Stomatology Department of Peking University Third Hospital from January 2016 to December 2019. Data were collected by medical records review. Univariate analysis of treatment outcome was performed for the total RCT group, initial RCT group, re-RCT group and EMS group, respectively. Multivariate logistic regression was performed for the three RCT groups, respectively, but not for the EMS group. Results:The overall success of treatment for AP was 73.8%. The success rate of RCT in 229 cases was 70.7%, while that of EMS in 34 cases was 94.1%. The failure of RCT was significantly higher for elderly patients [odds ratio (OR) =1.025, P=0.013], teeth with incomplete fracture (OR =7.082, P=0.013), teeth with a greater crown root ratio (OR =1.198, P=0.029), teeth treated by a general dentist (OR =2.16, P=0.042) and teeth with unqualified treatment (OR =2.841, P=0.002). Of the 166 teeth treated by initial RCT, the success was 68.1%. A greater crown root ratio (OR =1.333, P=0.004) was identified as a risk factor for treatment.Of the 63 teeth treated by re-RCT, the success was 77.8%. A lower success was observed in teeth with unqualified treatment (OR =5.291, P=0.018). With regard to EMS, the univariate analysis showed that none of the variables were significantly related to the outcome.Conclusions: For AP treated by RCT, age, incomplete tooth fracture, crown root ratio, doctor classification and unqualified treatment had a strong impact on determining outcome. For initial RCT, crown root ratio was a significant outcome predictor, while for re-RCT, unqualified treatment was a strong statistically significant factor. No significant difference was found between the success of initial RCT and re-RCT for AP.

Atopic dermatitis (AD) is a common disease clinically characterized by chronic recurrent eczematous lesions, dry skin, and pruritus. AD can negatively impact patients’ quality of life. The prevalence of AD in China has been increasing during the past few decades. Based on the most recent advances in the treatment of AD, we updated the 2014 version of the Guidelines for Diagnosis and Treatment of Atopic Dermatitis in China regarding the definition, epidemiology, pathogenesis, clinical classification, diagnosis, prevention, and treatment of AD.

Multiple idiopathic external cervical root resorption is a rare condition with numerous predisposing factors that have not yet been clearly elucidated. In addition, its diagnosis and treatment pose challenges for clinicians, and thus, the extraction of the involved teeth is commonly performed. Here, we report a 29‐year‐old pregnant woman with no contributory medical or family/social history who experienced cervical root resorption that progressed aggressively and involved all permanent teeth. This case is unique owing to the involvement of all teeth. Reports of multiple idiopathic external cervical root resorption are rare in the literature, and the pathogenesis of the condition is poorly understood. This report aims to add an additional case to the existing literature, analyse the underlying mechanisms and provide clinicians with some guidance in diagnosing cervical root resorption.