Effects of Dental Restorative Materials on Human Dental Pulp Stem Cells

Abstract

Numerous studies have approved the significance of DPSC since it may differentiate into various cells to support tissue engineering and stem cell therapy The source teeth are frequently filled with material including composite resin glass ionomer and zinc oxide eugenol-base materials due to caries Cytotoxicity and genotoxicity of these restorative materials have been well-documented in in vitro studies However only some of these compounds were also found to diffuse through the dentinal tubules and reach the pulp tissue even in the presence of an intact dentin barrier However there is until now fragmentary information available on their biological effects on dental pulp stem cell (DPSC) Only few in vitro studies report that dental materials disturb the differentiation of DPSC Therefore it is important to develop further in vivo study in tissue engineering and stem cell therapy The purpose of this study was to investigate the response of dental pulp stem cell after application of dental restorations in vivo In this study volunteers with scheduled extracted human molar teeth were collected under informed consent The cavity floor prepared on the occlusal surface of molars was restored with composite resin glass ionomer and zinc oxide eugenol-base materials The 36 molars teeth filled with dental restoration were extracted after 7 days and 30-60 days then were processed for histopathological evaluation in order to examine the pulp response and the distribution of stem-cells The histopathological finding showed mild pulp damage in teeth with restoration in cavities The immunoreactivity of CD44 and ?-SMA was obviously found in the pulp core of all groups The stem cell percentage of the groups at day 30-60 decreased comparing with the groups at day 7 with the composite resin group showing the lowest value among groups There was no significant difference among the tested groups and control group In established culture experiment we investigated the morphology proliferation stemness and differentiation potential of DPSCs For each group isolated DPSCs exhibited small spindle-like homogeneous morphology In cell proliferation all groups of cell formed adherent clonogenic cell cluster; however there were similar CFU counts between all groups In WST1 assay no significant difference was observed among groups Oct4 expression increased in resin-30days group comparing with control group Mineralized nodules were formed after 2 and 4 weeks of osteogenic induction The result suggested that resinous monomers may reduce the viability of DPSC but increased the stemness of the survival DPSCs under inflammatory stimulation Additionally the dental restoration caused mild damage of pulp tissue with little alteration in density of DPSCs and the osteogenic potential was kept after dental restoration

Date of Award	2014 Aug 30
Original language	English
Supervisor	Yuh-Ling Chen (Supervisor)