Preservation of the dental pulp depends on the stimulation of hard tissue formation within the pulp itself. The presence of sphingosine-1-phosphate (S1P) in vivo has attracted considerable attention. S1P reportedly promotes osteoblast differentiation, and is believed to be involved in hard tissue formation. In the present study, we assessed the ability of S1P to induce hard tissue formation in cultured human dental pulp cells (hDPCs). hDPCs were cultured from aseptically extracted pulp tissue obtained from the first premolar of 20s-year-old patients that required orthodontic treatment. The effect of S1P on hard tissue formation was observed by measuring alkaline phosphatase (ALP) activity and performing alizarin red staining. Additionally, BMP-2 mRNA, and BMP-2 and DSPP protein expression levels were examined to confirm hard tissue formation. We also investigated the expression of the S1P receptor mRNA in without stimulation by S1P and changes in intracellular calcium ion concentration ([Ca²⁺]i) dynamics in S1P-stimulated hDPCs. Stimulation of cultured hDPCs with S1P increased ALP activity and enhanced alizarin red staining. Additionally, S1P elevated BMP-2 mRNA expression, BMP-2 and DSPP protein levels. Moreover, mRNA expressions of S1P receptors 1-3 were also observed in cultured hDPCs. S1P enhanced hard tissue formation and the expressions of markers of hard tissue formation including BMP-2 and DSPP incltured hDPCs. Moreover, S1P induces an increase in [Ca²⁺]i levels by facilitating the release of Ca²⁺ from the endoplasmic reticulum via S1P receptor 1-3.

Glucose is important role for cellular functions. However, the behavior of osteoblasts in low glucose condition remains unclear. Therefore, this study aimed to elucidate the effects of low glucose conditions on the biological functions of osteoblasts. MC3T3-E1cells as one of osteoblast-like cells were cultured in MEM with five different glucose concentrations (0, 25, 50, 75, and 100 mg/dl). Then, low glucose conditions decreased the live cell number, proliferation, and migration of MC3T3-E1 cells. Alkaline phosphatase activity, mineralization, runx2, and osteocalcin production were also suppressed, whereas autophagy and extracellular signal-regulated kinase expression was increased under low glucose conditions. These results suggest that glucose may regulate osteoblast proliferation and differentiation.

Elemental analysis of a 12% gold-silver-palladium alloy and bovine teeth was conducted by X-ray microanalysis, and the results were transformed into multidimensional vectors. Standard values for a metal material and an inorganic material were also developed from the manufacturers’ declared values and vectorized in the same manner. A cosine similarity search between the vectors of the analysis data and those of the standard values was performed to experimentally ascertain whether it is possible to estimate the origins of the two types of samples, namely the 12% gold-silver-palladium alloy and bovine teeth. The results showed that the cosine similarity to the expected standard values was >99% for the metal sample and exceeded 90% for the bovine teeth, sufficiently demonstrating the potential for accurate origin identification. This method, which expresses the outcome as a single probabilistic percentage output, was found to be highly objective and easy to evaluate in the context of information sharing.

Diabetes is a metabolic disorder that causes a long-term hyperglycemic state with complications that affect multiple tissues, including bone. HMGB1, a nonhistone chromosomal binding protein, is released from the nucleus of damaged cells and secreted extracellularly, where it mediates inflammatory responses. Hyperglycemia induces HMGB1 expression in cell types associated with diabetic complications. Therefore, we evaluated the effect of a high glucose concentration on HMGB1 production in MG-63 osteoblast-like cells. MG-63 cells were cultured in the presence of glucose at 5.5 mM (control) or 25.0 mM (high glucose). The mRNA levels of HMGB1, HMGB1 receptors (RAGE, TLR2, and TLR4), HSP90AA1, and inflammatory cytokines (IL-6 and TNF-α) were analyzed by quantitative PCR. The protein levels of HMGB1 and TNF-α were evaluated by ELISA, immunofluorescence staining, and Western blotting. The mRNA levels of HMGB1, HSP90AA1, RAGE, TLR2, TLR4, TNF-α, and IL-6 were higher in the high glucose group than in the control group. Also, high glucose upregulated the HMGB1 protein level. Anti-HMGB1 antibodies partially blocked the high glucose-induced increase in the TNF-α, but not IL-6, mRNA level. The TNF-α protein level in the presence of high glucose was also decreased by anti-HMGB1 antibodies. In conclusion, high glucose induced the expression and secretion of HMGB1 in MG-63 cells, suggesting that the extracellular HMGB1 induces TNF-α expression in osteoblasts under high glucose conditions.

In the present study, the soft tissue response toward a fibronectin–immobilized zirconia implant was evaluated by animal experiment. Quartz crystal microbalance (QCM) analyses for atelocollagen adsorption to zirconia were also performed. Cylindrically shaped yttria stabilized tetragonal zirconia polycrystals (Y-TZP) was sandblasted and acid etching–treated (SLA/Y-TZP). Fibronectin–immobilized Y-TZP (Fn/Y-TZP) was obtained using the tresyl chloride–activated method. Implants were placed in the tooth socket of the extracted maxillary teeth of rats. Soft tissue responses 3-weeks after implantation were observed. Long collagen fibers perpendicularly oriented to the Y-TZP implant surface were more abundant in Fn/Y-TZP than in SLA/Y-TZP. The lengths of vertically oriented collagen fibers on the palatal side and the total of the buccal and palatal sides of Fn/Y-TZP were significantly higher than that of SLA/Y-TZP. Fn/Y-TZP showed a significantly higher area of vertically oriented collagen fibers on the buccal side and the total sides as compared to SLA/Y-TZP. There were no significant differences among the ratios of epithelial attachments to fibrous attachments. QCM analyses indicated that the pre–adsorption of fibronectin significantly decreased the amounts of atelocollagen adsorption. In conclusion, the immobilization of fibronectin had a clear effect on the orientation of gingival fibers toward the zirconia implant surface. Atelocollagen adsorption to zirconia was influenced with by fibronectin pre–adsorption.

Based on the concept of minimal intervention (MI) in dental treatment, a mixture of amorphous calcium phosphate (ACP) and HEPES (2-[4-(2-hydroxyethyl)-1-piperazinyl] ethanesulfonic acid) buffer solution (ACP + HEPES) was prepared with the objective of using an inorganic material equivalent to tooth substance as a dental restoration material and performing pulp protection treatment. In this study, a stoichiometric investigation of this solution was conducted, an experimental model of dentin caries lesions was prepared, and the effect on mineralization when the ACP + HEPES mixture was used to fill the dentin was evaluated. It was found that, 20 minutes after the cavity was filled with the ACP + HEPES buffer mixture, the ACP filler has undergone a phase transition, and hydroxyapatite (HAP) was deposited. Simultaneously, the ions eluted from the ACP had permeated the demineralized dentin caries lesion, restoring the mineral content of the demineralized dentin by more than 13%. This indicates that not only are calcium and phosphate ions supplied to the demineralized dentin continuously from the ACP + HEPES buffer mixture, but also that ACP fillings crystallize as HAP in a short period of time.

Low-intensity pulsed ultrasonic (LIPUS) is a noninvasive force promoting bone regeneration as mechanical stimulation. Integrins mediate numerous intracellular signaling pathways, including mitogen-activated protein kinase (MAPK) and calcium influx through focal adhesion. A non-receptor tyrosine kinase of proline-rich tyrosine kinase 2 (PYK2) associates with integrins at focal adhesions. A previous study reported that intracellular Ca²⁺ levels regulate the activation of PYK2 induced by mechanical strain in osteoblasts. However, the roles of PYK2 on the expression of extracellular matrix (ECM) proteins involved in osteogenesis and osteoblast differentiation induced by LIPUS remain unclear. We aimed to investigate the roles of PYK2 on the expression of transcription factors runt-related transcription factor 2 (Runx2) and osterix, which regulate osteoblast differentiation, ECM proteins, and the downstream intracellular signaling pathway, including PYK2 and focal adhesion kinase (FAK) in MC3T3-E1 cells when treated with LIPUS. LIPUS enhanced the phosphorylation of PYK2 and extracellular signal-regulated kinase2 (ERK2) and induced the expression of Runx2, osterix, type I collagen, osteocalcin, and calcium content in ECM. However, siPYK2 and PYK2 inhibitor PF431396 suppressed these stimulatory effects of LIPUS. These results suggest that LIPUS induces osteoblast differentiation mediated by the PYK2-ERK2 signaling in MC3T3-E1 cells.

Periodontal surgery to treat gingival recession or root exposure and improve peri-implant esthetics often requires soft tissue grafting. Allogeneic or heterologous collagen matrix can be a useful alternative to autologous soft tissue grafts via the avoidance of the invasive procedure of harvesting autologous tissues. A variety of collagen matrix products are on the market. However, little is known about the morphological characteristics of these products. Therefore, this study aimed to analyze the morphological characteristics of the allogeneic or heterologous collagen matrices available today. Cross-sectional and surface specimens of five acellular collagen matrix products were prepared, and the morphology of each specimen was analyzed using scanning electron microscopy. Mucograft and Collprotect showed two-layer or three-layer structures with porous spongious collagen, whereas Derma, Mucoderm, and Alloderm consisted of a single layer of compressed collagen. The structural differences of these commercially available collagen matrices may be attributable to the differences in the composition of animal tissue and collagen structure from which they are derived.

This study compared the effects of three intravenous sedation techniques used during mandibular third molar extraction in dental patients to find a suitable method with high safety and comfort. Patients undergoing third molar extraction at Yantai Stomatology Hospital of Binzhou Medical University and Yantai Zhifu Hospital Dental Clinic from November 2021 to December 2022 were enrolled and randomly assigned to three groups: group A received propofol and esketamine (n=50), group B received propofol and dexmedetomidine (n=50), and group C received propofol (n=50; control). The primary monitoring indicators included vital signs, blood gas analysis, bispectral index (BIS) score, and adverse reactions at T0 (admission), T1 (start of surgery), T2 (10 min after start of surgery), and T3 (end of surgery). The secondary monitoring indicators included recovery time, patient satisfaction, and doctor satisfaction. Among the three groups of patients, MAP and HR of group A were higher than group B and group C, while group C had higher MAP and HR than group B. The indicators of respiratory function SPO₂, PaO₂ and PaCO₂ of group B were worse than those of group A and group C, and the BIS value of group B was also lower, but patient satisfaction and doctor satisfaction were the highest. Patients in group C had shorter wake time, followed by group B. Group A woke up the slowest. Group A had higher incidence of hypertension, sychnosphygmia, hallucination, restlessness, and dizziness than group B, but lower incidence of hypertension, sychnosphygmia, hallucination, and dizziness than group C. Groups A and C had lower bradyarrhythmia incidence . Thus, the three sedation techniques are effective during mandibular third molar extraction and are safe for use in surgical sedation. Regarding comfort and treatment satisfaction, dexmedetomidine and propofol combination is more suitable for mandibular third molar extraction.