DLX6-AS1 regulates odonto/osteogenic differentiation in dental pulp cells under the control of BMP9 via the miR-128-3p/MAPK14 axis: A laboratory investigation.

AIM: The regenerative capacity of dental pulp relies on the odonto/osteogenic differentiation of dental pulp cells (DPCs), but dynamic microenvironmental changes hinder the process. Bone morphogenetic protein 9 (BMP9) promotes differentiation of DPCs towards an odonto/osteogenic lineage, forming dentinal-like tissue. However, the molecular mechanism underlying its action remains unclear. This study investigates the role of DLX6 antisense RNA 1 (DLX6-AS1) in odonto/osteogenic differentiation induced by BMP9. METHODOLOGY: Custom RT2 profiler PCR array, quantitative Real-Time PCR (qRT-PCR) and western blots were used to investigate the expression pattern of DLX6-AS1 and its potential signal axis. Osteogenic ability was evaluated using alkaline phosphatase and alizarin red S staining. Interactions between lncRNA and miRNA, as well as miRNA and mRNA, were predicted through bioinformatic assays, which were subsequently validated via RNA immunoprecipitation and dual luciferase reporter assays. Student's t-test or one-way ANOVA with post hoc Tukey HSD tests were employed for data analysis, with a p-value of less than .05 considered statistically significant. RESULTS: DLX6-AS1 was upregulated upon BMP9 overexpression in DPCs, thereby promoting odonto/osteogenic differentiation. Additionally, miR-128-3p participated in BMP9-induced odonto/osteogenic differentiation by interacting with the downstream signal MAPK14. Modifying the expression of miR-128-3p and transfecting pcMAPK14/siMAPK14 had a rescue impact on odonto/osteogenic differentiation downstream of DLX6-AS1. Lastly, miR-128-3p directly interacted with both MAPK14 and DLX6-AS1. CONCLUSIONS: DLX6-AS1 could regulate the odonto/osteogenic differentiation of DPCs under the control of BMP9 through the miR-128-3p/MAPK14 axis.

Comparison of the Outcome of Intentional Replantation in Teeth with or without Periodontal Involvement: A Retrospective Study.

OBJECTIVE: Intentional replantation (IR) is considered as a viable treatment option to preserve the teeth with apical periodontitis. This study aimed to compare the treatment outcomes of IR in teeth with or without periodontal involvement, and to investigate the influence of related factors. METHODS: A total of 157 teeth with a documented history of IR between September 2012 and November 2022 and a follow-up duration of more than 1 year were included. The samples included 100 teeth with simple apical periodontitis and 57 teeth with combined periodontal-endodontic lesions (CPEL). Clinical and radiographic criteria were used to evaluate treatment outcomes including functional retention and extraction. Chi-square analyses and Fisher's exact tests were used to compare bivariate associations between outcomes and clinical or demographic variables. Kaplan-Meier analyses were used to evaluate the cumulative survival rate of the intentionally replanted teeth. RESULTS: The overall cumulative survival rates were 93.0% at 1 year, 76.7% at 5 years, and 56.2% at 10 years. Among the 100 teeth with simple apical periodontitis, the survival rates were 93.0%, 86.7%, and 78.8% at the same time points. In contrast, 57 teeth with CPEL exhibited survival rates of 93.0%, 65.0%, and 36.9%, respectively. The primary postoperative complications that led to extraction were periodontal involvement (51.9%), tooth fracture (18.5%), external root resorption (18.5%), and persistent apical periodontitis (11.1%). The outcomes of teeth with CPEL were significantly affected by the presence of a sinus tract and crown restoration. In contrast, no significant prognostic factors were identified for teeth without periodontal involvement. CONCLUSION: The long-term prognosis of teeth with CPEL is significantly worse than those with simple apical periodontitis. The main reason of extraction was periodontal involvement. Regular periodontal maintenance and appropriate crown restoration may help to improve the prognosis for teeth with CPEL.

The outcome of combined use of iRoot BP Plus and iRoot SP for root-end filling in endodontic microsurgery: a randomized controlled trial.

OBJECTIVES: Root-end filling is important for the clinical outcome of endodontic microsurgery. Our previous study showed that combined application of iRoot BP Plus Root Repair Material (BP-RRM) and iRoot SP Injectable Root Canal Sealer (SP-RCS) in root-end filling exhibited better apical sealing as compared to the application of BP-RRM alone. The aim of this randomized controlled clinical trial was to evaluate the effect of the combined use of BP-RRM and SP-RCS on the prognosis of teeth with refractory periapical diseases after endodontic microsurgery. MATERIALS AND METHODS: 240 teeth with refractory periapical diseases scheduled for endodontic microsurgery were randomly divided into BP-RRM/SP-RCS group (n = 120) and BP-RRM group (n = 120). The patients were followed up at 3 months, 6 months, and 12 months after endodontic microsurgery. Pre- and post-operative clinical and radiographic examinations were performed to evaluate the treatment outcome. The 1-year success rate of endodontic microsurgery in BP-RRM/SP-RCS and BP-RRM groups was compared by Chi-square test. Factors that might impact the prognosis were further analyzed using Chi-square test or Fisher's exact test. RESULTS: A total of 221 teeth completed the 12-month follow-up. The 1-year success rates of the BP-RRM/SP-RCS and BP-RRM groups were 94.5% (104/110) and 92.8% (103/111), respectively. The combined use of BP-RRM and SP-RCS achieved a clinical outcome comparable to BP-RRM alone (P = 0.784). Tooth type (P = 0.002), through-and-through/apico-marginal lesion (P = 0.049), periodontal status (P < 0.0001), and Kim's lesion classification (P < 0.0001) were critical factors associated with the 1-year success of endodontic microsurgery. CONCLUSIONS: The combined use of BP-RRM and SP-RCS is a practicable method for root-end filling in endodontic microsurgery with a satisfactory 1-year clinical outcome. CLINICAL RELEVANCE: The combined application of BP-RRM and SP-RCS in EMS is an effective root-end filling method with a satisfactory 1-year clinical outcome. TRIAL REGISTRATION: This study was registered in the Chinese Clinical Trial Registry (ChiCTR2100052174).

Immortalized cell lines derived from dental/odontogenic tissue.

Stem cells derived from dental/odontogenic tissue have the property of multiple differentiation and are prospective in tooth regenerative medicine and cellular and molecular studies. However, in the face of cellular senescence soon in vitro, the proliferation ability of the cells is limited, so studies are hindered to some extent. Fortunately, immortalization strategies are expected to solve the above issues. Cellular immortalization is that cells are immortalized by introducing oncogenes, human telomerase reverse transcriptase genes (hTERT), or miscellaneous immortalization genes to get unlimited proliferation. At present, a variety of immortalized stem cells from dental/odontogenic tissue has been successfully generated, such as dental pulp stem cells (DPSCs), periodontal ligament cells (PDLs), stem cells from human exfoliated deciduous teeth (SHEDs), dental papilla cells (DPCs), and tooth germ mesenchymal cells (TGMCs). This review summarized establishment and applications of immortalized stem cells from dental/odontogenic tissues and then discussed the advantages and challenges of immortalization.

Combined micro-apical surgery and vital pulp therapy in mandibular second molars with external root resorption caused by impacted teeth.

OBJECTIVES: This study aimed to establish a new treatment of the mandibular second molars with external root resorption caused by impacted teeth to preserve the affected teeth and their vital pulps. METHODS: For mandibular second molars clinically diagnosed as external root resorption caused by impacted teeth, debridement and removal of the root at the resorption site via micro-apical surgery and direct capping of the pulp with bioactive material on the surface of the root amputation via vital pulp therapy were performed immediately after the impacted teeth were extracted. RESULTS: The external root resorption of the affected tooth was ceased. It was asymptomatic with intact crown, normal pulp, periapical alveolar bone reconstruction, normal periodontal ligament, continuous bone sclerosis, and no periapical translucency in radiographic examination at the 1-year postoperative follow-up, thus showing good prognosis. CONCLUSIONS: Simultaneous combination of micro-apical surgery and vital pulp therapy after extraction of impacted teeth could successfully preserve mandibular second molars with ERR caused by impacted teeth and their vital pulps.

Assessment of the coronal root canal morphology of permanent maxillary first molars using digital 3D-reconstruction technology based on micro-computed tomography data.

Background: The design of minimally invasive access has become a hotspot. This study aimed to evaluate the coronal root canal morphology of permanent maxillary first molars to facilitate the design of endodontic access cavities for minimally invasive linear access. Materials and methods: A selection of 91 permanent maxillary first molars was evaluated. Three-dimensional tooth models were reconstructed using micro-computed tomography data. Root canal prevalence and coronal root canal landmarks were recorded. The positional coordinates of landmarks in the horizontal plane and the angles and directions of coronal root canal curvature in the horizontal and axial planes were also assessed. Results: The detection rates of the mesiobuccal (MB), distobuccal (DB), and palatal (P) canals were 100%, whereas that of the second mesiobuccal (MB2) canals was 68.1%. All landmarks were located near the central fossa. In the axial plane, the average angles of coronal root canal curvature were DB (27.05°) > MB (25.43°) > P (20.71°) in teeth with three canals, and MB2 (33.20°) > MB (29.61°) > DB (28.40°) > P (23.69°) in teeth with four canals. In the horizontal plane, the average angles were P (78.15°) > DB (42.34°) > MB (32.41°) in teeth with three canals, and P (81.26°) > DB (43.44°) > MB (41.22°) > MB2 (9.41°) in teeth with four canals. Conclusion: In maxillary first molars, coronal root canals tend to converge towards the occlusal surface. The results of this study could be applied to improve the precision of endodontic access cavity designs of minimally invasive access.

The role of MIF in periodontitis: A potential pathogenic driver, biomarker, and therapeutic target.

OBJECTIVE: Periodontitis is an inflammatory disease that involves an imbalance in the oral microbiota, activation of inflammatory and immune responses, and alveolar bone destruction. Macrophage migration inhibitory factor (MIF) is a versatile cytokine involved in several pathological reactions, including inflammatory processes and bone destruction, both of which are characteristics of periodontitis. While the roles of MIF in cancer and other immune diseases have been extensively characterized, its role in periodontitis remains inconclusive. RESULTS: In this review, we describe a comprehensive analysis of the potential roles of MIF in periodontitis from the perspective of immune response and bone regulation at the cellular and molecular levels. Moreover, we discuss its potential reliability as a novel diagnostic and therapeutic target for periodontitis. CONCLUSION: This review can aid dental researchers and clinicians in understanding the current state of MIF-related pathogenesis, diagnosis, and treatment of periodontitis.

Effect of photon-induced photoacoustic streaming and shock-wave enhanced emission photoacoustic streaming technique on the removal of the smear layer after root canal preparation in curved root canals.

Background/purpose: The efficiency of root canal irrigation has an important impact on the prognosis of root canal treatment. Photon-induced photoacoustic streaming (PIPS) and shock wave enhanced emission photoacoustic streaming (SWEEPS) are the special modality of Er: YAG laser, whether can they improve the efficiency of root canal irrigation remains to be studied. Materials and methods: Fifty human teeth with curved root canals were collected and stored in the thymol solution until used in the study. After traditional endodontic cavities preparation, root canals were prepared to size #35 with a 0.04 taper. The final irrigating techniques were as follows: (I) manual dynamic activation (MDA), (II) ultrasonically activated irrigation (UAI), (III) sonically activated irrigation (SAI), (IV) PIPS, and (V) SWEEPS. Fifty teeth were randomly divided into five groups mentioned above. After root canal preparation, the roots were cleaved longitudinally. The dentine surfaces were photographed from the coronal, middle, and apical third of the root by scanning electron microscopy operated at a low vacuum. Two examiners separately graded each image according to the remained smear layer situations. Results: PIPS and SWEEPS groups showed fewer smear layers remaining than the others in the middle and the apical third (P < 0.05) of the root canal. In contrast, in the coronal third, five groups showed no significant difference (P > 0.05). Conclusion: PIPS and SWEEPS showed superior smear layer clearing efficiency than traditional irrigating techniques in curved root canals.

The effect of BMP9 on inflammation in the early stage of pulpitis.

BACKGROUND: 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.

The Potential Immunomodulatory Roles of Semaphorin 4D in Human Periapical Lesions.

INTRODUCTION: Semaphorin 4D (SEMA4D) is an important immunoregulator in the development of inflammatory diseases. Currently, the role of SEMA4D in human apical periodontitis remains unclear. This study aims to investigate the expression of SEMA4D and its potential immunomodulatory roles in apical periodontitis. METHODS: A total of 31 periapical tissues and 6 healthy gingival tissues were used in this experiment. Hematoxylin-eosin staining, immunohistochemical staining, and multiplex immunofluorescence staining were performed for histologic examination and immunochemical analysis. For data processing, the number of SEMA4D+, CD4+, CD8+, and CD20+ cells was analyzed by QuPath. In addition, the colocalization of SEMA4D with CD4, CD8, and CD20 was detected. RESULTS: Radicular cysts (RCs) (n = 18) and periapical granulomas (PGs) (n = 13) were identified by histologic evaluation. The number of SEMA4D+ cells in PGs was significantly greater than that in RCs (P < .05). T-cell and B-cell infiltration did not differ significantly between RCs and PGs. An increased number of CD20+ cells was observed in both types of apical periodontitis compared to CD8+ cells and CD4+ cells. Additionally, the presence of SEMA4D/CD4 and SEMA4D/CD20 double-positive cells was also markedly higher in PGs than in RCs. CONCLUSION: The expression of SEMA4D and related immune cells showed different characteristics between RCs and PGs. The disparate expression patterns indicated the possible different pathologic states of the 2 types of periapical lesions. This study provides a new perspective on the description of the comprehensive microenvironment of periapical lesions.

The effect of BMP9 on inflammation in the early stage of pulpitis

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.

Protective Actions in Apical Periodontitis: The Regenerative Bioactivities Led by Mesenchymal Stem Cells.

Resulting from bacterial infection, apical periodontitis (AP) is a common inflammatory disease of the periapical region of the tooth. The regeneration of the destroyed periapical alveolar bone and the surrounding periodontium tissues has long been a difficult task in clinical practice. These lesions are closely related to pathogen invasion and an overreactive immune response. It is worth noting that the protective healing process occurs simultaneously, in which mesenchymal stem cells (MSCs) have a crucial function in mediating the immune system and promoting regeneration. Here, we review the recent studies related to AP, with a focus on the regulatory network of MSCs. We also discuss the potential therapeutic approaches of MSCs in inflammatory diseases to provide a basis for promoting tissue regeneration and modulating inflammation in AP. A deeper understanding of the protective action of MSCs and the regulatory networks will help to delineate the underlying mechanisms of AP and pave the way for stem-cell-based regenerative medicine in the future.

The potential regulatory role of BMP9 in inflammatory responses.

Inflammation is a protective response of the body to pathogens and injury. Hence, it is particularly important to explore the pathogenesis and key regulatory factors of inflammation. BMP9 is a unique member of the BMP family, which is widely known for its strong osteogenic potential and insensitivity to the inhibition of BMP3. Recently, several studies have reported an underlying pivotal link between BMP9 and inflammation. What is clear, though not well understood, is that BMP9 plays a role in inflammation in a carefully choreographed manner in different contexts. In this review, we have summarized current studies focusing on BMP9 and inflammation in various tissues and the latest advances in BMP9 expression, signal transduction, and crystal structure to better understand the relationship between BMP9 and inflammation. In addition, we also briefly summarized the inflammatory characteristics of some TGF-ß superfamily members to provide better insights and ideas for the study of BMP9 and inflammation.

Emerging roles of lncRNAs in the pathogenesis, diagnosis, and treatment of trigeminal neuralgia.

Trigeminal neuralgia (TN) is one of the most common neuropathic pain disorders and is often combined with other comorbidities if managed inadequately. However, the present understanding of its pathogenesis at the molecular level remains lacking. Long noncoding RNAs (lncRNAs) play crucial roles in neuropathic pain, and many studies have reported that specific lncRNAs are related to TN. This review summarizes the current understanding of lncRNAs in the pathogenesis, diagnosis, and treatment of TN. Recent studies have shown that the lncRNAs uc.48+, Gm14461, MRAK009713 and NONRATT021972 are potential candidate loci for the diagnosis and treatment of TN. The current diagnostic system could be enhanced and improved by a workflow for selecting transcriptomic biomarkers and the development of lncRNA-based molecular diagnostic systems for TN. The discovery of lncRNAs potentially impacts drug selection for TN; however, the current supporting evidence is limited to preclinical studies. Additional studies are needed to further test the diagnostic and therapeutic value of lncRNAs in TN.

Semaphorin 7A Accelerates the Inflammatory Osteolysis of Periapical Lesions.

INTRODUCTION: Semaphorin 7A (SEMA7A), the only class VII semaphorin member, has been considered as a potent immunomodulatory regulator whose function in periapical lesions remains unclear. In our previous study, we found that SEMA7A was up-regulated in human periapical periodontitis and might be involved in the immune response and tissue destruction of periapical lesions. In this research, we aimed to further explore the specifical regulatory role of SEMA7A as well as its regulatory mechanisms in the inflammatory progression of periapical lesions. METHODS: Human periodontal ligament cells (hPDLCs) were collected from intact, caries-free, and healthy third molars and stimulated with recombinant human/mouse SEMA7A (rSEMA7A). Real-time quantitative polymerase chain reaction (RT-qPCR), Western blot analysis, and enzyme-linked immunosorbent assay were used to detect the messenger RNA and protein levels of inflammatory cytokines and matrix metalloproteinases (MMPs) in hPDLCs. Twenty C57BL/6 mice were randomly divided into 4 groups: the healthy control group, pulp exposure group, pulp exposure and saline treatment group, and pulp exposure and rSEMA7A treatment group. Twenty microliters of sterile saline or 4 µg rSEMA7A were injected respectively into the buccal mucosa around the root apex at day 0, 7, and 14. Mandibular tissues were collected at day 21. Micro-computed tomographic and immunohistochemical staining were used to identify the bone destruction and inflammatory infiltration in periapical areas. Finally, an AKT inhibitor (LY294002) was used to pretreat hPDLCs before rSEMA7A stimulation to determine the role of AKT signaling activation in this process. RESULTS: After treatment with rSEMA7A, the messenger RNA and protein levels of interleukin (IL)-1ß, IL-18, cyclooxygenase-2, MMP-1, and MMP-3 were remarkably up-regulated in hPDLCs. For in vivo experiments, compared with the other 3 groups, the treatment of rSEMA7A aggravated the osteolysis of alveolar bone and promoted the infiltration of immune cells into the apex area, along with increased expression levels of IL-1ß, IL-18, MMP-1, and MMP-3. Furthermore, we found that the proinflammatory role of SEMA7A could be inhibited by the application of the AKT inhibitor (LY294002). CONCLUSIONS: SEMA7A likely aggravates the inflammatory reaction and bone destruction of existing periapical lesions. The proinflammatory role of SEMA7A in hPDLCs could partially be mediated through the AKT signaling transduction pathway.

NELL1 augments osteogenesis and inhibits inflammation of human periodontal ligament stem cells induced by BMP9.

BACKGROUND: Periodontitis could lead to periodontal destruction such as the loss of alveolar bone. The issue that how to achieve the regeneration of alveolar bone and periodontal tissues under the inflammatory environment needs to be solved urgently. Bone morphogenetic protein 9 (BMP9) is one of the most potent osteoinductive BMPs and induces osteogenic differentiation of mesenchymal stem cells. The aim of this study is to explore the possible effect of BMP9 on the osteogenic differentiation of inflammatory periodontal ligament stem cells (PDLSCs). METHODS: Human PDLSCs were cultured in osteoinductive medium with 1 µg/mL lipopolysaccharide Porphyromonas gingivitis (LPS-PG). Adenoviral vector expressing system was used to overexpress target genes. In vitro expression of osteogenic markers was assessed by quantitative reverse transcription polymerase chain reaction, Western blotting, alkaline phosphatase assay, and alizarin red staining. Subcutaneous implantation nude mice models were used to evaluate the effects of BMP9 on PDLSCs in vivo. Microcomputed tomography, hematoxylin & eosin staining, and trichrome staining were performed to assess ectopic bone formation. RESULTS: In the LPS-PG induced inflammatory environment, BMP9 promoted osteogenic differentiation of PDLSCs, but upregulated the expression of inflammatory markers (P > 0.05); NEL-like protein 1 (NELL1) downregulated the expression of inflammation genes in PDLSCs induced by BMP9, while augmenting BMP9-induced osteogenesis of the cells both in vitro and in vivo. In the above process, the MAPK/p38/ERK signaling pathway was triggered by NELL1. CONCLUSION: The combination use of BMP9 and NELL1 might have the potential to promote the regeneration of alveolar bone in periodontitis.

The Potential Roles of T Cells in Periapical Lesions.

INTRODUCTION: Periapical lesions are inflammatory diseases mainly caused by microbial infection from the root canal system, affecting the integrity of alveolar bone, periapical cementum, and periodontal ligament. The invasion of pathogenic microorganisms activates local inflammation and host immune response, especially the recruitment and differentiation of T cells. Many studies have discussed the fundamental roles of T cell-related immunological regulation and the possible clinical significance of cytokine disorders in periapical lesions. However, oral pathogen-mediated T cell immune response is far more clarified. Therefore, the aim of this study was to discuss the research status of T cell-related immunology involved in the progression of periapical lesions and potential future directions. METHODS: We conducted a literature review focusing on T cell-related immunology in periapical lesions by searching PubMed, Web of Science, Scopus and ScienceDirect online databases. RESULTS: In total 108 articles were involved in this narrative review. During the development of periapical lesions, the infiltrated number of different types of T cells and the secretion of T cell-related cytokines in root apex region reflected the inflammatory status of periapical lesions. In addition, it was also highly correlated with the periapical bone destruction. Future study could attempt to provide a wider and deeper study on the expression profile and regulatory function of T cells in the development of periapical lesions. CONCLUSION: This review would help us understand the essence of the T cell-related pathology of periapical lesions and raise the potential therapeutic targets for the treatment of apical periodontitis.

Potential relationship between clinical symptoms and the root canal microbiomes of root filled teeth based on the next-generation sequencing.

AIM: To determine the microorganism in root canal systems of root filled teeth with periapical disease and their relationship with clinical symptoms using next-generation sequencing. METHODOLOGY: The roots of 10 extracted teeth were collected from 10 patients who presented with post-treatment apical periodontitis (PTAP; six with symptoms and four without symptoms). Each root was divided horizontally into two parts (apical and coronal segments) and cryo-pulverized. Microbial communities were detected using 16S rDNA hypervariable V3-V4 region. The diversity, principal coordinate analysis and linear discriminant analysis effect size were performed in the symptomatic and asymptomatic groups (apical and coronal parts respectively). A Mann-Whitney test and an analysis of similarities were applied for intergroup analysis, at a significance level of 5%. RESULTS: A total of 23 phyla, 257 genera and 425 species were detected. Firmicutes was the most abundant phylum in all samples. Three phyla (Fusobacteria, Synergistetes and unidentified_Bacteria) and seven genera (Fusobacterium, Porphyromonas, Phocaeicola, Olsenella, Campylobacter, Tannerella and Fretibacterium) were significantly more abundant in the symptomatic patients (p < .05), whereas asymptomatic patients had more Sphingomonas. The species more significantly abundant in the symptomatic samples were Porphyromonas gingivalis, Phocaeicola abscessus, Campylobacter showae, Tannerella forsythia and Olsenella uli (p < .05). CONCLUSIONS: A greater microbial diversity was observed in root filled teeth with PTAP compared to earlier reports. Several genera and species in root canal systems might be associated with clinical symptoms of PTAP.

The influence of the maxillary sinus on maxillary posterior tooth endodontic microsurgery / 口腔疾病防治

@#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.

Function of Dental Follicle Progenitor/Stem Cells and Their Potential in Regenerative Medicine: From Mechanisms to Applications.

Dental follicle progenitor/stem cells (DFPCs) are a group of dental mesenchyme stem cells that lie in the dental follicle and play a critical role in tooth development and maintaining function. Originating from neural crest, DFPCs harbor a multipotential differentiation capacity. More importantly, they have superiorities, including the easy accessibility and abundant sources, active self-renewal ability and noncontroversial sources compared with other stem cells, making them an attractive candidate in the field of tissue engineering. Recent advances highlight the excellent properties of DFPCs in regeneration of orofacial tissues, including alveolar bone repair, periodontium regeneration and bio-root complex formation. Furthermore, they play a unique role in maintaining a favorable microenvironment for stem cells, immunomodulation and nervous related tissue regeneration. This review is intended to summarize the current knowledge of DFPCs, including their stem cell properties, physiological functions and clinical application potential. A deep understanding of DFPCs can thus inspire novel perspectives in regenerative medicine in the future.