Molecular Response of Pulp Fibroblasts after Stimulation with Pulp Capping Materials

Abstract

This in vitro study evaluated cell viability and metabolism, nitric oxide release and production of two chemokines and one cytokine by cultured human dental pulp fibroblasts (HDPF) in contact with two glass ionomer cements (Ketac Molar-KM and Vitrebond-VB), Single Bond (SB) and calcium hydroxide (Dycal-DY). Cultures of HDPF were established by means of an explant technique. The specimens were prepared under sterile conditions and in disks measuring 5 mm x 2 mm obtained from a prefabricated mold and placed on a permeable membrane to avoid direct contact with the cells. Cytotoxicity was assessed by Trypan Blue exclusion method and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Nitric oxide release in cell supernatant was detected by the Griess Method whereas stromal derived factor-1 alpha (SDF-1α or CXCL12), chemokine (C-X-C motif) ligand 8 [Interleukin 8 (IL-8 or CXCL8)] and interleukin-6 (IL-6) were detected by ELISA. RT-qPCR was employed for gene expression analysis. Statistical analyses were performed by One-way ANOVA followed by Tukey’s post hoc test for materials independent of the time, and Two-way ANOVA followed by Bonferroni correction test for the comparisons between materials and experimental time (p<0.05). Cytotoxic tests showed significant differences only for DY. Protein levels and mRNA expression were significantly increased for IL-8 for both periods of time. IL-6 production increased when fibroblasts were stimulated by KM. SDF-1α protein production and mRNA expression were not affected by any of the materials. There was a decrease in nitrate/nitrite levels only for KM. Although DY caused intense cell death and did not stimulate the production of the inflammatory mediators evaluated in this work, it is known that this event seems to be fundamental for the process of repair of the pulp tissue and formation of mineralized barrier. KM and VB increased production of proteins related to the inflammatory process, thus favoring tissue repair. Therefore, although these glass ionomer cements did not lead to large cell death, they should be used with caution.

Examination of surface porosity of current pulp capping materials by micro-computed tomography (micro-CT) method

“…Calcium hydroxide is the traditional pulp capping material, and it has been accepted as the gold standard of pulp capping material for a very long time. The first outcome of calcium hydroxide placement on the exposed pulp area is the appearance of superficial necrosis due to its high potential of hydrogen (pH) (12.5) [31,32]. When necrosis occurs, the pulp is stimulated to defend and mend itself by creating a reparative dentine bridge via the processes of cellular differentiation, extracellular matrix secretion and mineralization [32].…”

“…When necrosis occurs, the pulp is stimulated to defend and mend itself by creating a reparative dentine bridge via the processes of cellular differentiation, extracellular matrix secretion and mineralization [32]. In the study by Modena et al [31], calcium hydroxide was much more cytotoxic, reduced cell metabolism of cultured human dental pulp fibroblasts, and caused severe cell death. Canoğlu et al [33] evaluated the success of direct pulp capping of primary molars with calcium hydroxide and mineral trioxide aggregate (MTA) after hemorrhage control with different solutions.…”

Ways of Maintaining Pulp Vitality: Narrative Literature Review

“…Direct pulp capping addresses accidental pulp exposure by applying a biomaterial directly onto the exposed pulp, fostering the formation of a mineralized barrier and preserving pulp vitality (8). The evolution of materials used for this purpose-from calcium hydroxide, historically revered as the gold standard, to modern alternatives like Mineral Trioxide Aggregate (MTA) and Biodentinreflects significant advancements in enhancing tissue response, pulpal healing, and dentin regeneration (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). Pulpotomy involves the removal of coronal pulp to preserve the vitality of the remaining radicular pulp, particularly in cases of deep carious lesions without signs of irreversible pulpitis (30,31).…”

Direct pulp capping procedures – Evidence and practice

“…In previous decades, calcium hydroxide (CH) has been the material of choice and gold standard for DPC [50] , [51] , [52] , [53] . One of the desirable properties of CH is that it has a high pH, which is responsible for the stimulation of fibroblasts [54] . It raises the pH of acidic solutions, inhibits microorganism’s growth, and encourages the healing and defense mechanisms of pulp tissue [55] , [56] .…”