The influence of addition of osteogenic supplements to mineral trioxide aggregate on the gene expression level of odontoblastic markers following pulp capping in dogs

This study investigates the effect of addition of dexamethasone, vitamin D-3, or chitosan to mineral trioxide aggregate (MTA) on the gene expression level of dentin sialophosphoprotein (DSPP) and matrix extracellular phosphoglycoprotein (MEPE) after pulp capping in dogs. Pulp exposure was performed in sixty dogs' teeth. The teeth were classified into 3 equal groups according to the evaluation period. Group 1: 7 days, group 2: 21 days and group 3: 60 days. Each group was further subdivided according to the pulp capping material used, into subgroup A: MTA + dexamethasone, subgroup B: MTA + dexamethasone + vitamin D-3, subgroup C: MTA + chitosan and subgroup D: MTA. According to the group, the pulps of the capped teeth were removed for analysis of the relative mRNA expression level of DSPP and MEPE using PCR. Statistical analysis of all data was performed. In subgroup A, significant expression was observed of DSPP (P <= 0.05) in group 2 up to 18.8 relative fold change while in subgroup B a significant upregulated gene expression of DSPP (P<0.05) up to 29.4 relative fold change was seen. Significant upregulated DSPP expression (P <= 0.05) was recorded in groups 1 and 2 up to 6.9 and 3.6 relative fold change, respectively in subgroup C. In conclusion, dexamethasone, with or without vitamin D-3 and chitosan, are synergistic odontogenic inducers with MTA for differentiation of dental pulp cells in dogs. The upregulation of DSPP is a good marker for this differentiation.