We aimed to investigate the regulatory effects of HMGB1/TLR4 signaling pathway on the expression of IL-10 and VEGF in human bone marrow mesenchymal stem cells.

Background: The present study aimed to investigate the expression of stromal cell‐derived factor‐1 (SDF‐1) after tooth extraction in rats and its regulatory effect on the expression of osteopontin (OPN) and vascular endothelial growth factor (VEGF). Methods: The first mandibular molar of the rats on the left was extracted, the histopathological changes of the extraction sockets were observed, and the SDF‐1 protein and mRNA expression were measured at 0, 1, 4, 7, 10, and 14 days. Furthermore, we used AMD3100 to block SDF‐1/CXC chemokine receptor 4 (CXCR4) signaling, and the expression changes of SDF‐1, OPN, and VEGF were observed. Results: At 1 day, the socket was filled with a blood clot. At 4 days, the granulation tissues were formed at the socket. At 7 days, the extraction socket was filled with mature fibrous connective tissue. At 10 days, a large amount of new trabecular bone was regenerated. At 14 days, the newly formed socket bone underwent remodeling. The expression level of SDF‐1 began to increase on the first day after tooth extraction and then peaked at 4 days. Then, SDF‐1 expression gradually declined and finally returned to the baseline level at 14 days. Moreover, the application of AMD3100 decreased the secretion of OPN and VEGF, both at protein and mRNA levels. Conclusions: The expression of SDF‐1 increased first and then decreased after tooth extraction. SDF‐1 may play a regulatory role in the expression of OPN and VEGF. Plain language summary: Tooth extraction is one of the most common operations that cause oral tissue defects and tooth loss. The healing of the tooth extraction wound affects the results of the later denture restoration and implant surgery. In this study, the expression of stromal cell‐derived factor‐1 (SDF‐1) increased first and then decreased after tooth extraction. It was found that after blocking the SDF‐1 signaling pathway, the expression levels of osteopontin (OPN) and vascular endothelial growth factor (VEGF) decreased correspondingly. While OPN was a marker of bone maturation, VEGF could promote angiogenesis and thus tissue repair. In conclusion, SDF‐1 may be involved in the process of tissue damage repair by regulating the expression of OPN and VEGF.

This study used cone-beam computed tomography (CBCT) to measure the anatomical structures of the apical foramen of mandibular second premolars at Nolla stage 8. A total of 80 mandibular second premolars at Nolla stage 8 with deformed central cusp (DCC) deformity were selected as the observation group, and another 80 normal mandibular second premolars at the same stage were selected as the control group. The mesiodistal diameter (A-B) and buccolingual diameter (C-D) of the apical foramen, as well as the mesiodistal diameter (A1-B1), buccolingual diameter (C1-D1), and superoinferior diameter (E-F) of the periapical radiolucency, were measured using the built-in software of the CBCT system. The data were analyzed using SPSS 26.0 software. Results: In the observation group, the values of A-B, C-D, A1-B1, C1-D1, and E-F were (2.47 ± 0.26) mm, (3.28 ± 0.50) mm, (3.26 ± 0.30) mm, (4.25 ± 0.58) mm, and (3.06 ± 0.27) mm, respectively. In the control group, the corresponding values were (2.43 ± 0.29) mm, (3.27 ± 0.34) mm, (3.26 ± 0.41) mm, (4.24 ± 0.40) mm, and (3.28 ± 0.43) mm, respectively. Within each group, significant differences were found between A-B and C-D, as well as between A1-B1 and C1-D1 ( P < .001). In both the observation and control groups, females exhibited significantly lower values than males for A-B, C-D, A1-B1, C1-D1, and E-F ( P < .05). A-B and C-D were positively correlated with A1-B1, C1-D1, and E-F, respectively. This study confirmed that in Nolla stage 8 mandibular second premolars, the buccolingual diameters of both the apical foramen and periapical radiolucency were larger than the mesiodistal diameters, and females had smaller values for all parameters. Teeth with DCC but without apical periodontitis showed no significant anatomical differences from normal teeth. As the first CBCT-based comparison of apical anatomy between DCC and normal mandibular second premolars at this developmental stage, these results provide useful imaging references for early diagnosis and therapeutic monitoring of apical periodontitis caused by DCC fracture.