Experts consensus on the procedure of dental operative microscope in endodontics and operative dentistry.

The dental operative microscope has been widely employed in the field of dentistry, particularly in endodontics and operative dentistry, resulting in significant advancements in the effectiveness of root canal therapy, endodontic surgery, and dental restoration. However, the improper use of this microscope continues to be common in clinical settings, primarily due to operators' insufficient understanding and proficiency in both the features and established operating procedures of this equipment. In October 2019, Professor Jingping Liang, Vice Chairman of the Society of Cariology and Endodontology, Chinese Stomatological Association, organized a consensus meeting with Chinese experts in endodontics and operative dentistry. The objective of this meeting was to establish a standard operation procedure for the dental operative microscope. Subsequently, a consensus was reached and officially issued. Over the span of about four years, the content of this consensus has been further developed and improved through practical experience.

EVL Promotes Osteo-/Odontogenic Differentiation of Dental Pulp Stem Cells via Activating JNK Signaling Pathway.

Objective: Human dental pulp stem cells (hDPSCs) were recognized as a suitable and promising source of stem cells in dental pulp regeneration. However, the mechanism by which hDPSCs differentiation into osteo-/odontogenic lineage remains unclear. Ena/VASP-like protein (EVL) has been found to be involved in diverse biological processes. In this study, we explored the role and underlying mechanism of EVL in osteo-/odontogenic differentiation of hDPSCs. Methods: Expression of EVL was detected in hDPSCs by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot (WB) analyses during osteo-/odontogenic differentiation. The function of EVL in osteo-/odontogenic differentiation and involvement of MAPK signaling pathways were evaluated by alkaline phosphatase (ALP) staining and activity, alizarin red staining (ARS), and qRT-PCR and western blot analyses. Results: The expression of EVL was upregulated during osteo-/odontogenic differentiation of hDPSCs. Overexpression of EVL significantly increased osteo-/odontogenic capacity of hDPSCs, which was reflected in increased alkaline phosphatase (ALP) staining, ALP activity, mineralized nodule formation, and the expressions of genes related to osteo-/odontogenic differentiation, while downregulation of EVL inhibited it. In addition, EVL activated the JNK pathway and phosphorylation of p38 MAPK during differentiation procedure of hDPSCs. The EVL-enhanced differentiation of DPSCs was suppressed by blocking the JNK pathway, rather than the p38 MAPK pathway. Conclusion: EVL promotes the osteo-/odontogenic differentiation of hDPSCs by activating the JNK pathway, providing a future target for osteo-/odontogenic differentiation and dental pulp regeneration.

miR-342-5p inhibits odonto/osteogenic differentiation of human dental pulp stem cells via targeting Wnt7b.

OBJECTIVE: Human dental pulp stem cells (hDPSCs) constitute a promising source of stem cells in tissue engineering. However, the molecular mechanism of differentiation in hDPSCs remains largely unclear. MicroRNAs (miRNAs) play crucial roles in lineage-specific differentiation of stem cells. The present study investigated the function of miRNA-342-5p in the odonto/osteogenic differentiation of hDPSCs. METHODS: The miRNA array profiling and quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) revealed the expression of miR-342-5p during odonto/osteogenic differentiation of hDPSCs. hDPSCs were treated with miR-342-5p mimic and inhibitor to investigate the regulatory roles of miR-342-5p in the differentiation of hDPSCs. Moreover, miR-342-5p inhibitor and small interference RNA (siRNA) targeting Wnt7b were applied to explore the regulatory mechanism of miR-342-5p. RESULTS: Downregulated miR-342-5p was observed during odonto/osteogenic differentiation of hDPSCs. The overexpression of miR-342-5p inhibited the odonto/osteogenic potential of DPSCs, as indicated by low levels of alkaline phosphatase activity, calcium deposition formation, and odonto/osteogenic differentiation markers, whereas silencing of miR-342-5p exhibited the opposite effect. When co-treated with siRNA targeting Wnt7b and miR-342-5p inhibitor in hDPSCs, the odonto/osteogenic potential and activation of Wnt7b/ß-catenin pathway were attenuated. CONCLUSIONS: This study showed that miR-342-5p inhibits the odonto/osteogenic differentiation of hDPSCs by interfering with Wnt/ß-catenin signaling via targeting Wnt7b.

CircSERPINE2 weakens IL-1ß-caused apoptosis and extracellular matrix degradation of chondrocytes by regulating miR-495/TGFBR2 axis.

The dysregulated circular RNAs (circRNAs) are relevant to the development of osteoarthritis (OA). The circRNA serpin family E member 2 (circSERPINE2) is dysregulated in OA, while the role and mechanism of circSERPINE2 in OA are largely unknown. The aim of our research is to explore how and whether circSERPINE2 regulates interleukin-1ß (IL-1ß)-caused chondrocyte damage in OA. In the present study, the chondrocytes (CHON-001 cells) were exposed to IL-1ß to mimic the injury in OA. CircSERPINE2, microRNA-495 (miR-495) and transforming growth factor-ß receptor 2 (TGFBR2) abundances were detected via quantitative reverse-transcription polymerase chain reaction (qRT-PCR) or Western blot. Cell apoptosis was assessed via viability, apoptotic rate and caspase-3 activity. Extracellular matrix was investigated by levels of Sry-type high-mobility-group box 9 (SOX9), collagen type II α 1 (COL2A1) and Aggrecan using Western blot. The interaction among circSERPINE2, miR-495 and TGFBR2 was assessed via dual-luciferase reporter analysis and RNA immunoprecipitation (RIP). The results showed that circSERPINE2 expression was reduced in OA patients and IL-1ß-treated chondrocytes. CircSERPINE2 overexpression mitigated IL-1ß-caused apoptosis and extracellular matrix degradation. miR-495 was targeted by circSERPINE2 and up-regulated in OA patients and IL-1ß-treated chondrocytes. miR-495 up-regulation reversed overexpression of circSERPINE2-mediated inhibition of apoptosis and extracellular matrix degradation. TGFBR2 was targeted by miR-495 and lowly expressed in OA patients and IL-1ß-treated chondrocytes. CircSERPINE2 could mediate TGFBR2 expression by binding with miR-495. As a conclusion, circSERPINE2 attenuated IL-1ß-caused apoptosis and extracellular matrix degradation of chondrocytes by regulating miR-495/TGFBR2 axis, indicating a new target for OA treatment.

The Antimicrobial Peptide LL-37 Promotes Migration and Odonto/Osteogenic Differentiation of Stem Cells from the Apical Papilla through the Akt/Wnt/ß-catenin Signaling Pathway.

INTRODUCTION: The antimicrobial peptide LL-37, in addition to its broad spectrum of antibacterial function, can promote odontogenesis and osteogenesis. Stem cells from the apical papilla (SCAPs) are essential for the formation of dentin/bonelike tissues. However, little information on these cells is available in regenerative endodontics. This study aimed to evaluate the effects of LL-37 on the proliferation, migration, and differentiation of SCAPs. METHODS: SCAPs were isolated, cultured, and characterized. Cell viability was analyzed by Cell Counting Kit-8 assays (Dojindo, Kumamoto, Japan). Cell migration was investigated by transwell assays. Dentin sialophosphoprotein, dentin matrix protein 1, runt-related transcription factor 2, and osterix were assessed by quantitative polymerase chain reaction and Western blots. Alkaline phosphatase (ALP) activity and ALP staining were assessed to determine the in vitro potential for osteogenic differentiation. The involvement of the Akt/Wnt/ß-catenin signaling pathway was also studied. RESULTS: In the 2.5-µg/mL LL-37 -treated group, cell proliferation and migration were up-regulated. Quantitative polymerase chain reaction and Western blot assays both revealed that LL-37 at 2.5 µg/mL up-regulated odonto/osteogenic markers (dentin sialophosphoprotein, dentin matrix protein 1, runt-related transcription factor 2, and osterix). LL-37 at 2.5 µg/mL significantly promoted ALP activity and increased the staining in SCAPs. In addition, the p-Akt and p-glycogen synthase kinase-3ß levels were increased in LL-37-treated SCAPs. The migratory and odonto/osteogenic differentiation capacities of SCAPs were inhibited after treatment with inhibitors LY294002 and XAV-939. CONCLUSIONS: Our study showed that LL-37 at 2.5 µg/mL promoted the migration and odonto/osteogenic differentiation of SCAPs by activating the Akt/Wnt/ß-catenin signaling pathway.

Adhesive interfacial characteristics and the related bonding performance of four self-etching adhesives with different functional monomers applied to dentin.

OBJECTIVES: To examine the interfacial chemical and morphological characteristics of four self-etching adhesives bonded to dentin with different functional monomers. Further, to evaluate the effects of this interaction between functional monomers and dentin on short-term in vitro bonding performance of the four adhesives. METHODS: Clearfil SE Bond (CSE) and Scotchbond Universal (SU) containing 10-methacryloxydecyl dihydrogen phosphate (10-MDP), Optibond XTR (OX) containing glycero-phosphate dimethacrylate (GPDM), and Adper Easy One (AEO) containing 6-methacryloyloxyhexyl dihydrogen phosphate (6-MHP) were applied to the dentin surface according to the instructions supplied with each. Interaction between the functional monomers and dentin was characterized using thin-film X-ray diffraction (TF-XRD) and scanning electron microscopy (SEM). The hydrophilicity of each acidic monomer was also assessed by chemical structure drawing software. Micro-tensile bond strength (µTBS) and nanoleakage were used to evaluate the bonding effectiveness of the adhesives, either immediately or after thermo-cycling (5°C-55°C) for 5000 cycles. RESULTS: TF-XRD showed that both CSE and SU exhibited 10-MDP-Ca nano-layering at the adhesive interface, but with different intensity when reacted with dentin. OX, that contains GPDM, demineralized the dentin surface more severely, forming long resin tags into the dentinal tubules, and gained the highest µTBS at the immediate time-point. Thermo-cycling adversely affected the µTBS and nanoleakage of AEO and OX, but had no significant influence on CSE and SU which contain 10-MDP. CONCLUSIONS: Self-etching adhesives containing different structures/concentrations of functional monomers produced adhesive interfaces with obviously different chemical and morphological characteristics, which may have a direct impact on bonding effectiveness. CLINICAL SIGNIFICANCE: Our findings support the concept that the stable chemical bonding produced by 10-MDP to the Ca of hydroxyapatite is advantageous for durability of adhesive-dentin bonds. In contrast a higher immediate bond strength was achieved with the functional monomer GPDM that etched and wetted the dentin surface better.

Effect of high-fructose corn syrup on Streptococcus mutans virulence gene expression and on tooth demineralization.

High-fructose corn syrup-55 (HFCS-55) has been widely welcomed in recent years as a substitute for sucrose on the basis of its favourable properties and price. The objective of this study was to determine the influence of HFCS-55 on the expression of Streptococcus mutans UA159 virulence genes and on tooth demineralization. Real-time reverse-transcription PCR (real-time RT-PCR) and microhardness evaluations were performed to examine gene expression and enamel demineralization, respectively, after treatment with HFCS-55 and/or sucrose. Significant up-regulation of glucosyltransferase B (gtfB) by HFCS-55 was found. A mixture of HFCS-55 and sucrose could positively enhance expression of glucan-binding protein (gbp) genes. Regarding acidogenicity, expression of the lactate dehydrogenase (ldh) gene was unaffected by HFCS-55. A notable finding in this study was that 5% HFCS-55 significantly enhanced expression of the intracellular response gene of the two-component VicRK signal transduction system (vicR). Demineralization testing showed that the microhardness of teeth decreased by a greater extent in response to HFCS-55 than in response to sucrose. The results indicate that HFCS-55 can enhance S. mutans biofilm formation indirectly in the presence of sucrose and that HFCS-55 has a more acidogenic potential than does sucrose. Summing up the real-time PCR and demineralization results, HFCS-55 appears to be no less cariogenic than sucrose in vitro - at least, not under the conditions of our experiments.

Characterization of oral bacterial diversity of irradiated patients by high-throughput sequencing.

The objective of this study was to investigate the compositional profiles and microbial shifts of oral microbiota during head-and-neck radiotherapy. Bioinformatic analysis based on 16S rRNA gene pyrosequencing was performed to assess the diversity and variation of oral microbiota of irradiated patients. Eight patients with head and neck cancers were involved in this study. For each patient, supragingival plaque samples were collected at seven time points before and during radiotherapy. A total of 147,232 qualified sequences were obtained through pyrosequencing and bioinformatic analysis, representing 3,460 species level operational taxonomic units (OTUs) and 140 genus level taxa. Temporal variations were observed across different time points and supported by cluster analysis based on weighted UniFrac metrics. Moreover, the low evenness of oral microbial communities in relative abundance was revealed by Lorenz curves. This study contributed to a better understanding of the detailed characterization of oral bacterial diversity of irradiated patients.

[Effect of compound Chinese traditional medicine on periapical periodontitis in dogs and cytotoxic assay].

PURPOSE: To assess the efficacy of compound Chinese traditional medicine(CTM), which is composed of gallic acid, magnolol and polysaccharide of Bletilla, against apical periodontitis in dogs and cytotoxic assay. METHODS: A animal model of apical periodontitis was built, CTM was then used to disinfect the root canal. The effect of the restoration of periapical bone in dogs was investigated after regular root canal filling. SAS6.12 software package was used for statistical analysis, and MTT was used to test cell toxicity of CTM. RESULTS: CTM can cure inflammation effectively, and CTM had no cytotoxic effect on periodontal ligament cells at 5-week. CONCLUSIONS: The compound Chinese traditional medicine may be an effective disinfecting drug for root canal disinfection.

Six cases report of differential diagnosis of periapical diseases.

The distinction of some particular forms of periapical area, involving diseases from regular periapical disease, is a matter of considerable importance when choosing a correct treatment. The aim of this study is to describe the differential diagnosis of periapical diseases from six rare cases in clinical practice. The six rare cases are examples of situations where it is difficult to make a differential diagnosis in clinical practice. By retrospective surveys on the clinical examination, radiographs and pathological results, six patients referred to endodontic treatment in our department were analyzed for the accuracy of diagnosis and therapy. The pathoses of the six cases included two atypical radical cysts, periapical cemental dysplasia, cemento-ossifying fibroma, thymus cancer metastasis in the periapical site and tuberculosis. This report indicates that endodontists should be cognizant of a few particular circumstances when clinically treating periapical diseases.

[Effect of compound Chinese traditional medicine on infected root canal bacteria biofilm].

PURPOSE: To assess the efficacy of compound Chinese traditional medicine(CTM), which composed of gallic acid, magnolol and polysaccharide of Blettila striata, against the infected root canal bacterial biofilm. METHODS: Actinomyces viscosus (Av), Enterococcus faecalis (Ef), Fusobacterium nucleatum (Fn) were composed to form biofilm, then confocal laser scan microscope (CLSM) was used to observe and study the bacterial activity. SAS6.12 software package was used for statistical analysis. RESULTS: The biofilm thickness reduced after treatment by both CTM and ZnO (P>0.05),while there was a significant decrease of the percentage of vital bacterias after treatment by CTM (P<0.01). CONCLUSIONS: The compound Chinese traditional medicine is effective on biofilm control, so that it would be an effective disinfecting drug for root canal sealers. Supported by Research Fund of Bureau of Traditional Chinese Medicine of Shanghai Municipality (Grant No.2008L008A).

[Quantitative evaluation of residual endodontic microorganisms after mechanical root canal preparation different chemical preparations by real-time PCR].

PURPOSE: To establish a quick, sensitive method for quantifying root canal flora and investigate the effects of different root canal preparations on the pathogenic bacteria at RNA level. METHODS: A total of 24 single-rooted teeth with chronic apical periodontitis were selected and prepared using 3% H2O2 combined with 1% NaClO, EDTA combined with 3% H(2)O(2),1% NaClO, respectively,the samples were taken before and after root canal preparation. After isolation of total RNA from the root canal samples, cDNA was synthesized by reverse transcription, and detected by real-time PCR. The data were analyzed with SAS 6.12 software package. RESULTS: The number of bacteria in the root canal reduced dramatically after mechanical preparation and irrigated using 3% H(2)O(2) and 1% NaClO(P<0.01). Further combined with EDTA, its effect was better than that of simply irrigated using 3% H(2)O(2) and 1% NaClO(P<0.05). CONCLUSIONS: Real-time PCR can be employed in the identification of bacteria flora in the root canal, both methods of root canal preparation can effectively reduce the number of bacteria flora.

[Cloning and the sequence analysis of the fish glutathione transferase Pi gene].

Using RT-PCR method, the glutathione transferase Pi cDNAs were cloned from Cyprinus carpio, Hypophthalmichthys molitrix, and Carassius auratus. The open reading frames (ORFs) from the 3 fishes were 627 bp long (encoding for 208 amino acids) with the initial code ATG and the terminal code TGA. The sequence similarity was 50% between fish and mammals, 33% between fish and amphibian, and 15% between fish and arthropoda, respectively. The sequence similarity was big among fishes, and the average value of the 4 cyprinids was about 85%. Phylogenetic tree was constructed for 13 species based on GST Pi amino acid sequences using MP (Maximum Parsimony) method. Two major clusters were recognized: cluster one consisted of Mammals (bootstrap 100) and cluster two consisted of fishes (bootstrap 93). Based on the sequences analyses of N/C domain of GST Pi, we proposed the detoxification mechanism of freshwater fishes that were thought to have stronger tolerance to microcystins.

[Analysis the effect on the stress of root canal wall of pulpless teeth by different degree of root canal preparation].

OBJECTIVE: To analyze the stress variations of wall of root canal of pulpless teeth that resulted from different diameters of root canal. METHODS: On the basis of the finite-element model of the mandibular first molar that modified by routine, diameter of root canal was modified and enlarged so as to the diameter of root canal was 1/3 and 1/2 of root diameter, then modified models were loaded and the maximal stress of each part of teeth and wall of root canal was calculated. RESULTS: The results revealed that enlargement of root canal diameter will bring on increase of stress of root canal wall at the orifice and coronal 1/3. The stress difference of lateral loading was greater than that of vertical loading. CONCLUSION: The principle of root canal preparation should be infected material removed and good shape of root canal gained. Over-preparation is unnecessary and harmful.

[Histological evaluation on repair of furcation perforation in dogs using mineral trioxide aggregate].

OBJECTIVE: To investigate histological response to immediate repair of different sizes of furcation perforation using MTA, Dycal and GIC. METHODS: Forty-two posterior teeth in three adult beagle dogs were randomly divided into two groups, small perforation group and large perforation group. Each group was then divided into three sub-groups which were repaired with MTA, Dycal and GIC respectively. The dogs were sacrificed 4 months later, and the specimens processed and examined under the light microscope. Inflammation, epithelial proliferation, and formation of hard tissue over the material were evaluated. RESULTS: In teeth repaired with MTA, five cases were free of inflammation, and the other nine cases were associated with slight or moderate inflammation. There was formation of cementum with cementoblast cells around it in four cases. In the group of Dycal, all specimens had moderate or severe inflammation. The deposition of irregular calcified tissues as well as a large quantity of inflamed cells were found in two cases of small perforation. Six cases presented epithelial proliferation. In the group of GIC, moderate or severe inflammation was seen in all cases except for one case of large perforation with fibrous tissues and sparse inflammatory cells around the material. Four cases presented epithelial proliferation. There was some relation between epithelial proliferation and size of perforation. CONCLUSION: MTA is superior to GIC and Dycal for immediate repairing furcation perforation in dogs owing to its less irritation to surrounding tissues and its ability to induce the formation of hard tissues.

[Analysis of the effect on the stress of root canal wall by vertical and lateral condensation procedures].

OBJECTIVE: To analyse the stress variations of root canal wall that resulted from vertical and lateral condensation. METHODS: On the basis of the finite-element model of the mandibular first molar that modified by step-back technique, mesial-buccal root canal was chosen as tested root canal and simulated the procedure of vertical and lateral condensation. The maximal stress of root canal wall and its position were calculated by special software upon different loading condition. RESULTS: Stress of root canal wall caused by vertical condensation was higher than that by lateral condensation on the same loading condition. Maximal stress of vertical condensation was located on loading section and one of lateral condensation was located on coronal and middle 1/3 of root. The lower the position that was loaded, the higher the stress of wall of root canal. CONCLUSION: Lateral condensation will not bring on vertical root fracture directly,but over-force and improper operation are both dangerous that gives rise to vertical root fracture with whichever method.

[Analysis the effect on the stress of wall of root canal by different proportion between crown and root].

OBJECTIVE: Use FEM to observe the relationship between the change of alveolar ridge's height and the stress change of wall of root canal. METHODS: Modify the model on the basis of the set up model of the mandibular first molar, simulating the height of alveolar ridge and reducing 1/4, 1/3, 1/2 of the height to set up modified model, and load on the modified model by vertical and lateral forces. Then calculate the maximum mises stress of each part of teeth and wall of root canal. RESULTS: The stress-changing tendency of each part of wall was similar to the changing tendency of each part of teeth, but the stress of wall was fewer than the stress of teeth. The stress value of original model was close to the modified model at the orifice. Then the stress of original model obviously reduced, and the stress of the modified model reached maximum in the coronal thirds, and when the fixed height was lower, the stress was larger, the stress reduced more slowly. The lateral stress was larger than the vertical stress, and when the fixed height was lower, the difference was more obvious. CONCLUSION: The change of alveolar ridge's height will affect the stress change of wall of root canal, and which is in an inverse proportion.

[Analysis the stress variations of the root canal wall of pulpless tooth by different root canal preparation with finite-element method].

OBJECTIVE: To analyze the stress variations of the root canal wall of pulpless tooth by different root canal preparations. METHODS: On the basis of the set up model of the mandibular first molar, modified model was established by simulation of the routine or step-back root canal preparation and filling in. Then the maximum mises stress of each part of teeth and wall of root canal were calculated by special finite-element software. RESULTS: The stress-changing tendency is similar between two modified models but the maximum mises stress of the model by step-back technique is a little greater than one by routine. The stress of wall of mesial-buccal root canal was the greatest and one of mesial-lingual root canal was the least at three root canals. The stress-changing tendency of modified models was similar to original model. The maximum mises stress of modified models was near or less than one of original model except that of amalgam layer because of material property alteration. CONCLUSION: Not only routine but step-back technique is an effective and safe method. Dentist can choose them in practice.