In Vitro Study of Dentin Hypersensitivity Treated by 980-nm Diode Laser

Introduction: To investigate the ultrastructural changes of dentin irradiated with 980-nm diode laser under different parameters and to observe the morphological alterations of odontoblasts and pulp tissue to determine the safety parameters of 980-nm diode laser in the treatment of dentin hypersensitivity (DH).Methods: Twenty extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into four areas and was irradiated by 980-nm diode laser under different parameters: Group A: control group, 0 J/cm²; Group B: 2 W/CW (continuous mode), 166 J/cm²; Group C: 3W/CW, 250 J/cm²; and Group D: 4W/CW, 333 J/cm². Ten additional extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into two areas and was irradiated by 980-nm diode laser: Group E: control group, 0 J/cm²; and Group F: 2.0 W/CW, 166 J/cm². The morphological alterations of the dentin surfaces and odontoblasts were examined with scanning electron microscopy (SEM), and the morphological alterations of the dental pulp tissue irradiated by laser were observed with an upright microscope.Results: The study demonstrated that dentinal tubules can be entirely blocked after irradiation by 980-nm diode laser, regardless of the parameter setting. Diode laser with settings of 2.0 W and 980-nm sealed exposed dentin tubules effectively, and no significant morphological alterations of the pulp and odontoblasts were observed after irradiation.Conclusions: Irradiation with 980-nm diode laser could be effective for routine clinical treatment of DH, and 2.0W/CW (166 J/cm²) was a suitable energy parameter due to its rapid sealing of the exposed dentin tubules and its safety to the odontoblasts and pulp tissue

Excessive addition split peak formed by the non-templated nucleotide addition property of Taq DNA polymerase after PCR amplification

Because of its non-template addition feature, Taq DNA polymerase can catalyze one or more extra nucleotides onto the 3′ terminus of PCR products. An extra peak is observed at DYS391 locus after the PCR products stored for 4 days at 4°C. To explore the formation mechanism of this artifact, PCR primers and amplicon sequences of Y-STR loci are analyzed, furthermore, PCR products storage conditions and termination of PCR are discussed. The extra peak is a + 2 addition product, which we call excessive addition split peak (EASP). The most significant difference between EASP and the incomplete addition of adenine product is that the size of EASP is about one base larger than the true allele, and the EASP locates on the right side of the real allelic peak. The EASP cannot be eliminated by increasing loading mixture volume and conducting heat denaturation prior to electrophoresis injection. However, the EASP is not observed when the PCR is terminated with ethylenediaminetetraacetic acid or formamide. These findings suggest that formation of EASP is a result of 3′ end non-template extension by Taq DNA polymerase, rather than being the result of DNA fragment secondary structure produced under a suboptimal electrophoresis condition. In addition, the EASP formation is affected by the primer sequences and the storage conditions of PCR products

Carbon States in Carbon-Encapsulated Nickel Nanoparticles Studied by Means of X-Ray Absorption, Emission, and Photoelectron Spectroscopies

Electronic structure of nickel nanoparticles encapsulated in carbon was characterized by photoelectron, X-ray absorption, and X-ray emission spectroscopies. Experimental spectra are compared with the density of states calculated in the frame of the density functional theory. The carbon shell of Ni nanoparticles has been found to be multilayer graphene with significant (about 6%) amount of Stone--Wales defects. Results of the experiments evidence protection of the metallic nanoparticles from the environmental degradation by providing a barrier against oxidation at least for two years. Exposure in air for 2 years leads to oxidation only of the carbon shell of Ni@C nanoparticles with coverage of functional groups.Comment: 16 pages, 6 figures, accepted in J. Phys. Chem.

Clinical progress on restoration by chairside CAD/CAM inlay

Tooth defects due to dental caries, trauma, abrasion, etc., are extremely common and can be treated by di⁃ rect or indirect restoration. Compared with resin directly filling the body, an inlay can better restore the occlusal contact relationship and the adjacent surface contact relationship and has good mechanical properties. In recent years, with the development of ceramic materials and bonding systems and the popularity of chairside CAD/CAM technology, the chair⁃ side CAD/CAM porcelain inlay restoration program has been well received by doctors and patients because of its accura⁃ cy, convenience, aesthetics, hardness and stability, and this program is widely used clinically. This review covers the re⁃ search status of various aspects such as indications and contraindications for chairside CAD/CAM inlay restoration, pre⁃ restoration preparation, tooth preparation, hole type, impression taking and design, porcelain block selection, bonding, polishing, postoperative doctors instructions, and common postoperative complications. It is expected to provide a refer⁃ ence for the clinical application of and research on chairside CAD/CAM inlay restoration technology

Clinical effect of semiconductor laser combined with total glucosides of paeony capsules for the treatment of erosive oral lichen planus

Objective To investigate the short⁃term clinical effect of semiconductor laser exposure combined with total glucosides of paeony (TGP) capsules for the treatment of erosive oral lichen planus (OLP). Methods Sixty⁃four patients with erosive oral lichen planus were randomly divided into two groups: the experimental group and the control group. Patients in the control group were treated with TGP capsules, while patients in the experimental group were treat⁃ ed with TGP capsules and semiconductor laser irradiation. The clinical effects were evaluated 3 months after treatment. The data were analyzed using the SPSS 17.0 software package. Results Three months after treatment, the effective rate in the experimental group was 90.6%, which was significantly higher than that in the control group (59.4%, χ2＝ 5.62, P < 0.05). The physical condition and visual analogue scale (VAS) scores in the experimental group were 2.17 ± 1.49 and 1.25 ± 1.29, respectively. The physical condition and VAS scores in the control group were 3.55 ± 1.41 and 2.09 ± 1.24, respectively. The physical condition and VAS scores in both groups were significantly higher after treat⁃ ment than before (P < 0.05). Three months after treatment, the physical condition score (t＝3.805) and VAS score (t＝ 2.655) in the experimental group were significant higher than those in the control group (P < 0.05). Conclusion Semi⁃ conductor laser irradiation combined with TGP capsules can improve the short⁃term clinical efficacy in the treatment of erosive OLP

circRNA Expression Profile in Dental Pulp Stem Cells during Odontogenic Differentiation

Introduction. Odontogenic differentiation of human dental pulp stem cells (hDPSCs) is a key step of pulp regeneration. Recent studies showed that circular RNAs (circRNAs) have many biological functions and that competing endogenous RNA (ceRNA) is their most common mechanism of action. However, the role of circRNAs in hDPSCs during odontogenesis is still unclear. Methods. Isolated hDPSCs were cultured in essential and odontogenic medium. Total RNA was extracted after 14 days of culture, and then, microarray analysis was performed to measure the differential expressions of circRNAs. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was then performed to validate the microarray results. Based on microarray data from this study and available in the database, a ceRNA network was constructed to investigate the potential function of circRNAs during odontogenesis. In addition, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to investigate the potential correlation between signaling pathways and circRNAs. In addition, qRT-PCR and Western blot analysis were used to explore the function of hsa_circRNA_104101. Results. We found 43 upregulated circRNAs and 144 downregulated circRNAs during the odontogenic differentiation process (fold change>1.5 and <-1.5, respectively; P<0.05). qRT-PCR results were in agreement with the microarray results. Bioinformatic analysis revealed that the Wnt signaling pathway and the TGF-β signaling pathway, as well as the other pathways associated with odontogenic differentiation, were correlated to the differentially expressed circRNAs. hsa_circRNA_104101 was proved to promote the odontogenic differentiation of hDPSCs. Conclusion. This study reported 187 circRNAs that were differentially expressed in hDPSCs during odontogenic differentiation. Bioinformatic analysis of the expression data suggested that circRNA-miRNA-mRNA networks might act as a crucial mechanism for hDPSC odontogenic differentiation, providing a theoretical foundation for the study of pulp regeneration regulation by circRNAs

The Tubular Penetration Depth and Adaption of Four Sealers: A Scanning Electron Microscopic Study

Background. The tubular penetration and adaptation of the sealer are important factors for successful root canal filling. The aim of this study was to evaluate the tubular penetration depth of four different sealers in the coronal, middle, and apical third of root canals as well as the adaptation of these sealers to root canal walls. Materials and Methods. 50 single-rooted teeth were prepared in this study. Forty-eight of them were filled with different sealers (Cortisomol, iRoot SP, AH-Plus, and RealSeal SE) and respective core filling materials. Then the specimens were sectioned and scanning electron microscopy was employed to assess the tubular penetration and adaptation of the sealers. Results. Our results demonstrated that the maximum penetration was exhibited by RealSeal SE, followed by AH-Plus, iRoot SP, and Cortisomol. As regards the adaptation property to root canal walls, AH-Plus has best adaptation capacity followed by iRoot SP, RealSeal SE, and Cortisomol. Conclusion. The tubular penetration and adaptation vary with the different sealers investigated. RealSeal SE showed the most optimal tubular penetration, whereas AH-Plus presented the best adaptation to the root canal walls

METTL3-Mediated lncSNHG7 m⁶A Modification in the Osteogenic/Odontogenic Differentiation of Human Dental Stem Cells

Background: Human dental pulp stem cells (hDPSCs) play an important role in endodontic regeneration. N6-methyladenosine (m6A) is the most common RNA modification, and noncoding RNAs have also been demonstrated to have regulatory roles in the expression of m6A regulatory proteins. However, the study on m6A modification in hDPSCs has not yet been conducted. Methods: Single base site PCR (MazF) was used to detect the m6A modification site of lncSNHG7 before and after mineralization of hDPSCs to screen the target m6A modification protein, and bioinformatics analysis was used to analyze the related pathways rich in lncSNHG7. After knockdown and overexpression of lncSNHG7 and METTL3, the osteogenic/odontogenic ability was detected. After METTL3 knockdown, the m6A modification level and its expression of lncSNHG7 were detected by MazF, and their binding was confirmed. Finally, the effects of lncSNHG7 and METTL3 on the Wnt/β-catenin pathway were detected. Results: MazF experiments revealed that lncSNHG7 had a m6A modification before and after mineralization of hDPSCs, and the occurrence site was 2081. METTL3 was most significantly upregulated after mineralization of hDPSCs. Knockdown/ overexpression of lncSNHG7 and METTL3 inhibited/promoted the osteogenic/odontogenic differentiation of hDPSCs. The m6A modification and expression of lncSNHG7 were both regulated by METTL3. Subsequently, lncSNHG7 and METTL3 were found to regulate the Wnt/β-catenin signaling pathway. Conclusion: These results revealed that METTL3 can activate the Wnt/β-catenin signaling pathway by regulating the m6A modification and expression of lncSNHG7 in hDPSCs to enhance the osteogenic/odontogenic differentiation of hDPSCs. Our study provides new insight into stem cell-based tissue engineering

Establishment and validation of the autophagy-related ceRNA network in irreversible pulpitis

Abstract Background The molecular mechanisms underlying the onset and progression of irreversible pulpitis have been studied for decades. Many studies have indicated a potential correlation between autophagy and this disease. Against the background of the competing endogenous RNA (ceRNA) theory, protein-coding RNA functions are linked with long noncoding RNAs (lncRNAs) and microRNAs (miRNAs). This mechanism has been widely studied in various fields but has rarely been reported in the context of irreversible pulpitis. The hub genes selected under this theory may represent the key to the interaction between autophagy and irreversible pulpitis. Results Filtering and differential expression analyses of the GSE92681 dataset, which contains data from 7 inflamed and 5 healthy pulp tissue samples, were conducted. The results were intersected with autophagy-related genes (ARGs), and 36 differentially expressed ARGs (DE-ARGs) were identified. Functional enrichment analysis and construction of the protein‒protein interaction (PPI) network of DE-ARGs were performed. Coexpression analysis was conducted between differentially expressed lncRNAs (DElncRNAs) and DE-ARGs, and 151 downregulated and 59 upregulated autophagy-related DElncRNAs (AR-DElncRNAs) were identified. StarBase and multiMiR were then used to predict related microRNAs of AR-DElncRNAs and DE-ARGs, respectively. We established ceRNA networks including 9 hub lncRNAs (HCP5 and AC112496.1 ↑; FENDRR, AC099850.1, ZSWIM8-AS1, DLX6-AS1, LAMTOR5-AS1, TMEM161B-AS1 and AC145207.5 ↓), which were validated by a qRT‒PCR analysis of pulp tissue from patients with irreversible pulpitis. Conclusion We constructed two networks consisting of 9 hub lncRNAs based on the comprehensive identification of autophagy-related ceRNAs. This study may provide novel insights into the interactive relationship between autophagy and irreversible pulpitis and identifies several lncRNAs that may serve as potential biological markers