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

Periodontal Regeneration of Teeth with Radicular Developmental Groove after Intentional Replantation: Two Case Reports

Our case reports probe whether intentional replantation is a feasible and successful treatment for teeth with radicular developmental groove. Radicular developmental groove is an anatomical malformation that often leads to combined periodontal-endodontic lesion. Treatment of complex radicular groove presents a great challenge to the operator. Two cases of periodontal compromised teeth with this developmental anomaly were treated with intentional replantation and followed up for 2 years. The teeth were asymptomatic and functional. The periodontal probing depths decreased from original 10 mm to 2-3 mm. The receded gingival papillae associated with the teeth was regenerated two years after intentional replantation. With careful case selection and treatment planning, intentional replantation may be a predictable alternative treatment modality for the combined endodontic‐periodontal lesion accompanied with radicular developmental groove

The effects of leptin on osteogenesis/odontogenic related gene expression of human apical papillary stem cells

Objective To investigate the effects of leptin on the proliferation of stem cells from human stem cells from the apical papilla (hSCAPs) and the expression of osteogenic/dentinogenic genes in vitro to provide an experimen⁃ tal basis for the sustainable development of young permanent teeth. Methods The tissue block method was used to iso⁃ late and culture hSCAPs from the apical papilla of the immature third permanent molar. The expression of leptin and OBRb in hSCAPs was detected using immunocytofluorescence staining, western blotting and reverse transcription poly⁃ merase chain reaction (RT⁃PCR) analysis. The hSCAPs was treated with 0.1 μg/mL of leptin (0.1 μg/mL group) or 1.5 μg/mL of leptin (1.5 μg/mL group) at different time points. The control group was treated with alpha⁃MEM medium. Cell proliferation was measured using the CCK8 assay and cell cycle analysis. QRT⁃PCR was used to detect the expres⁃ sion of related osteoblast/odontogenic genes for alkaline phosphatase (ALP), dentin matrix protein ⁃1 (DMP⁃1), dentin si⁃ alophosphoprotein (DSPP), and osteocalcin (OCN) mRNA. The differences between the treatment groups and the control group were analyzed statistically using one⁃way ANOVA followed by Bonferroni analysis. Results The expression of both leptin and OBRb were found in hSCAPs. Compared with the control group, the cell proliferation capacity and S phase cells in the treatment groups were higher than those in the control group, with the 1.5 μg /mL group displaying higher levels than 0.1 μg /mL group, and the treated hSCAPs demonstrated a higher proliferation rate and a higher ex⁃ pression of ALP, DSPP, and DMP⁃1 from day 3 to day 7, with the 1.5 μg /mL group displaying higher levels than 0.1 μg /mL group , and the difference was statistically significant (P < 0.05), at day 7. The treated hSCAPs demonstrated a lower expression of ALP, DSPP, and DMP⁃1. Compared with the control group, the treated hSCAPs demonstrated a high⁃ er expression of OCN from day 7 to day 14, with significantly higher expression in the 1.5 μg /mL group compared to the 0.1 μg /mL group. Conclusion Leptin may promote cell proliferation and upregulate the expression of relative os⁃ teogenic/dentinogenic genes

The Critical Role of Long Noncoding RNA in Osteogenic Differentiation of Human Bone Marrow Mesenchymal Stem Cells

Objective. Long noncoding RNAs (lncRNAs) have been demonstrated to regulate many biological processes including differentiation. However, their role in osteogenic differentiation was poorly known. Materials and Methods. In this study, we first globally profiled the differentially expressed lncRNAs and mRNAs during osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMMSCs). Bioinformatics analysis was performed to further analyze these significantly changed molecules. Then the role of lncRNA ENST00000502125.2 in the osteogenic differentiation was determined. Results. A number of lncRNAs and mRNAs were significantly differentially expressed during hBMMSC osteogenic differentiation. Among them, 433 lncRNAs and 956 mRNAs were continuously upregulated, while 232 lncRNAs and 229 mRNAs were continuously downregulated. Gene Ontology and KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis showed that carbohydrate derivative binding and complement and coagulation cascades were most correlated molecular function and pathway, respectively. Downregulation of lncRNA ENST00000502125.2 promoted the osteogenic differentiation of hBMMSCs, and opposite results were found when lncRNA ENST00000502125.2 was upregulated. Conclusions. lncRNAs play a critical role in the osteogenic differentiation of hBMMSCs and targeting lncRNA ENST00000502125.2 might be a promising strategy to promote osteogenic differentiation

Changes in protein expression between DPSCs and CDPSCs.

<p>A The merge of Cy3, Cy5 and Cy2. Distribution of 18 differentially expressed protein spots in fluorescence difference gel electrophoresis gels. Protein spots are indicated (arrows). B Enlarged images of the differentially expressed protein spots in DIGE analysis.</p

Altered expressions of two identified proteins.

<p>The expression level of the CCT2 protein was lower in DPSCs than CDPSCs (A, B). DPSCs have a higher expression level of stathmin protein compared with CDPSCs (C, D). The change in protein expression was consistent with that of proteomic analysis (*p<0.05, **p<0.01). Each experiment was repeated 3 times.</p

Proteomic Analysis of Mesenchymal Stem Cells from Normal and Deep Carious Dental Pulp

<div><p>Dental pulp stem cells (DPSCs), precursor cells of odontoblasts, are ideal seed cells for tooth tissue engineering and regeneration. Our previous study has demonstrated that stem cells exist in dental pulp with deep caries and are called carious dental pulp stem cells (CDPSCs). The results indicated that CDPSCs had a higher proliferative and stronger osteogenic differentiation potential than DPSCs. However, the molecular mechanisms responsible for the biological differences between DPSCs and CDPSCs are poorly understood. The aim of this study was to define the molecular features of DPSCs and CDPSCs by comparing the proteomic profiles using two-dimensional fluorescence difference gel electrophoresis (2-D DIGE) in combination with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Our results revealed that there were 18 protein spots differentially expressed between DPSCs and CDPSCs in a narrow pH range of 4 to 7. These differently expressed proteins are mostly involved in the regulation of cell proliferation, differentiation, cell cytoskeleton and motility. In addition, our results suggested that CDPSCs had a higher expression of antioxidative proteins that might protect CDPSCs from oxidative stress. This study explores some potential proteins responsible for the biological differences between DPSCs and CDPSCs and expands our understanding on the molecular mechanisms of mineralization of DPSCs in the formation of the dentin-pulp complex.</p></div

Differentiated expressed proteins between DPSCs and CDPSCs.

<p>Differentiated expressed proteins between DPSCs and CDPSCs.</p

2D-DIGE of DPSCs and CDPSCs.

<p>A Cy3 dye staining of CDPSCs B Cy5 dye staining of DPSCs. C Cy2-labeled internal standard proteome map.</p

Multilineage differentiation potential of DPSCs and CDPSCs.

<p>Mineralization assay in DPSCs and CDPSCs. Mineralized nodules formed by DPSCs (A) and CDPSCs (B) were detected by alizarin red S staining after 3 weeks of culture in mineralized-induced media. Adipogenic differentiation, visualized by oil red O staining, showed lipid vacuoles in DPSCs (C) and CDPSCs (D). Chondrogenic differentiation was visualized by alcian blue staining of DPSCs (E) and CDPSCs (F), demonstrated by the accretion of sulfated matrix. Scale bar = 100 µm. Each experiment was repeated 3 times.</p