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Abstract Bone morphogenetic protein 9 (BMP9) tends to be associated with various inflammatory responses of diseases, but its relationship with pulpitis remains unknown. Objective This study aimed to evaluate the effects and mechanisms of BMP9 in pulpitis. Methodology A rat model of pulpitis was used to evaluate the expression of BMP9, which was also analysed in Porphyromonas gingivalis lipopolysaccharide (Pg-LPS)-stimulated human dental pulp cells (hDPCs). The effects and mechanism of BMP9 on the regulation of inflammatory factors and matrix metalloproteinase-2 (MMP2) were evaluated using real-time quantitative PCR, western blotting, and immunocytofluorescence. Moreover, the migration ability of THP-1 monocyte-macrophages, treated with inflammatory supernate inhibited by BMP9, was previously tested by a transwell migration assay. Finally, a direct rat pulp capping model was used to evaluate in vivo the influence of the overexpression of BMP9 in pulpitis. Results The expression of BMP9 decreased after 24 h and increased after 3 and 7 d in rat pulpitis and inflammatory hDPCs. The overexpression of BMP9 inhibited the gene expression of inflammatory factors (IL-6, IL-8, and CCL2) and the secretion of IL-6 and MMP2 in Pg-LPS-stimulated hDPCs. The level of phosphorylated Smad1/5 was upregulated and the levels of phosphorylated ERK and JNK were downregulated. The inflammatory supernate of hDPCs inhibited by BMP9 reduced the migration of THP-1 cells. In rat pulp capping models, overexpressed BMP9 could partially restrain the development of dental pulp inflammation. Conclusion This is the first study to confirm that BMP9 is involved in the occurrence and development of pulpitis and can partially inhibit its severity in the early stage. These findings provided a theoretical reference for future studies on the mechanism of pulpitis and application of bioactive molecules in vital pulp therapy.
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Abstract Objective: To investigate the involvement of IL-6/STAT3 signaling pathway activation in macrophage polarization and bone destruction related to apical periodontitis (AP) stimulated by Porphyromonas gingivalis. Methodology: Macrophage polarization, IL-6/STAT3 expression, and the presence of P. gingivalis were detected in human AP tissues via RT-qPCR, western blotting, and immunohistochemistry staining. Murine bone marrow derived macrophages were isolated and cultured with P. gingivalis W83 in vitro, and levels of macrophage IL-6 expression, STAT3 phosphorylation, and macrophage polarization with or without the selective STAT3 phosphorylation inhibitor Stattic (5 μM) were detected via ELISA, western blotting, RT-qPCR, and flow cytometry, respectively. P. gingivalis-induced murine AP models were constructed, and bone destruction and macrophage polarization in the apical region were evaluated. Transwell co-culture systems were used to investigate the effects of macrophages infected with P. gingivalis on osteogenesis and osteoclastogenesis. Results: P. gingivalis was detected in human AP tissues that highly expressed IL-6/STAT3, and the M1 subtype of macrophages was more abundant in these tissues. P. gingivalis infection induced IL-6 expression, STAT3 phosphorylation, and M1 polarization of macrophages, while 5 μM of Stattic partially abolished these activation effects. Systemic STAT3 blockade via oral administration of Stattic at a dose of 25 mg kg-1 alleviated murine periapical bone resorption and apical infiltration of M1 macrophages induced by P. gingivalis infection in vivo. Furthermore, macrophages infected with P. gingivalis promoted bone destruction via secretion of IL-6, TNF-α, and RANKL, which hinder pre-osteoblast expression of Runx2 and accelerate pre-osteoclast expression of NFAT2. Conclusions: The activation of IL-6/STAT3 signaling pathway is involved in mediating macrophages M1 polarization in the P. gingivalis induced apical inflammatory context and may also be intimately involved in the bone loss caused by P. gingivalis infection, directing the M1 macrophage infiltration during the progression of AP.
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@#Endodontic microsurgery is one effective method for preserving teeth affected by periapical disease, and is also an essential technique for treating difficult cases. However, due to the restricted operating space at the posterior site and the proximity of the root apex to the maxillary sinus, endodontic surgery in the posterior maxillary area represents great challenges. This article summarizes the anatomical relationship between the maxillary sinus and the maxillary posterior teeth, the influence on endodontic microsurgery, and the application of assistive techniques on maxillary posterior teeth, such as 3D-printed surgical guides and ultrasonic osteotomes. Literature review results show that the spatial relationship between the apex of maxillary posterior teeth and the maxillary sinus is usually divided into three categories: the apex enters the maxillary sinus; the apex contacts the bottom of the maxillary sinus; and there is a distance between the apex and the bottom of the maxillary sinus. CBCT should be performed before the operation, and the periapical state of the tooth and the maxillary sinus and the distance between the lesions and the sinus floor should be considered to evaluate the difficulty of the operation. Meanwhile, during surgery, equipment such as surgical guides, endoscopes and ultrasonic osteotomes should be used to ensure that the operation is safer, reliable, precise and less invasive, but the clinical popularity of ultrasonic osteotomes still needs further promotion. Moreover, high-quality clinical studies on the long-term effects of micro-apical surgery in the posterior maxillary area are still lacking.
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Objective@#This study aims to compare the incidence of dentinal microcracks produced by ProTaper Universal (PTU) and ProTaper Gold (PTG) file systems during root canal procedures in different curved canals using a dyeing technique.@*Methods@#Sixty extracted human molars were divided into 3 groups of 20 samples each in terms of root curvature (mild bending group, 10 °-19 °; moderate bending group, 20 °-29 °; severe bending group, 30 °-39 °). Ten samples of each group were then randomly allocated to the PTU and PTG file systems. After preparation, all roots were stained using a dyeing method and sectioned at the most curved plane and 2 mm below and above the most curved plane with a low-speed saw under cold water. A stereomicroscope was used to inspect dentinal microcracks at 60 × magnification, and differences between these three instrument groups were analyzed using the chi-square test.@* Results @# The PTG file system induced significantly fewer dentinal microcracks for total, incomplete and complete cracks (P < 0.05), and the effect was more obvious with increasing canal curvature.@*Conclusion @# With the limitations of this in vitro study, it can be concluded that ProTaper Gold can result in fewer dentinal microcracks than ProTaper Universal.
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Objective@#To investigate the diagnosis, treatment and prognosis of nonodontogenic periapical lesions and to provide a reference for clinical diagnosis and treatment.@*Methods@# A case of a patient with right upper molar pulp with apical penetration and local occlusion admitted to the West China Stomatological Hospital of Sichuan University was retrospectively analyzed, and the curative effect of microapical surgery and pith preservation was also analyzed.@*Results @#The imaging features of tooth 16 showed periradicular radiolucency combined with local radiopaque lesions around the distal buccal apical area. Endodontic microsurgery was performed under local anesthesia. Soft tissue coverage was observed in the distal buccal apical area during the surgery, and no radiopaque tissue was detected. The distal buccal root apex was cut by 3 mm, and mineral trioxide aggregate was used for root-end backfilling. The postoperative pathological results revealed fibrous connective tissue. One-week recall X-ray examination showed tight root-end backfilling and no periradicular radiolucency; an electrical test of pulp vitality showed positive results. The four-year follow-up showed that there was no discoloration in tooth 16 and no significant difference in thermal and electrical tests of pulp vitality compared with control teeth. Combining the clinical manifestations, imaging features, surgical exploration results and pathological reports, the case was most likely to be cemental hypoplasia. Through the literature review, the treatment and healthy pulp preservation of such cases by endodontic microsurgery under the premise of preserving teeth has not been reported.@*Conclusion@#For maxillary posterior teeth with periapical lesions but healthy pulp, accurate estimation of pulp status, endodontic microsurgical exploration and application of bioactive materials can achieve vital pulp preservation while removing the lesions.