Acemannan Stimulate Dentin Bridge Formation in Partial Pulpotomized Canines’ Teeth

Objective:  To investigate the effect of acemannan on deciduous pulpal cells and the dental pulp response after partial pulpotomy treatment in an inflamed pulp in vivo. Method: In vitro study, human deciduous pulpal cells were treated with a range of acemannan concentration. Cell proliferation, new DNA synthesis, alkaline phosphatase activity, extracellular matrix and growth factor expression, and mineralization were determined using MTT assay, [³H]-thymidine incorporation, biochemical assay, enzyme-linked immunosorbent assay and western blot analysis, and alizarin red staining, respectively.  Moreover osteogenic gene expression was analyzed by cDNA microarray. In vivo study, pulpitis was induced by deep cavity preparation and contamination by lipopolysaccharide for 14 days. Class V cavities were prepared in 15 primary molar from healthy beagle dogs. Inflamed pulp was removed and then divided to three groups, acemannan, Mineral Trioxide Aggregate (MTA), or Formocresol. After 60 days, the experimental teeth were histopathologically examined for the degree of inflammation, dentin bridge formation, and soft tissue organization. Result:  Acemannan significantly increased pulp cell proliferation, alkaline phosphatase activity, type I collagen, vascular endothelial growth factor, bone morphogenetic protein-2 and -4, dentin sialoprotein expression and mineralization. Microarray data demonstrated that 23 genes were differentially regulated. In vivo study indicated that acemannan group showed complete and partial dentinal bridge formation with almost normal pulp tissue morphology. MTA group showed complete dentinal bridge formation with normal pulp tissue organization On the other hand, formocresol group presented moderate to severe inflammatory pulp response, absence of dentin bridge formation. From statistical analysis, acemannan and MTA groups have significantly better all histopathological response than formocresol group (p < 0.05). No significant difference was detected between acemannan and MTA group (p≥ 0.05). Conclusion: The data suggested that acemannan has a greater potential to be an alternative biomaterial for vital pulp therapy in primary teeth.