Abstract: A root canal filling material composition comprising a lithium salt has higher healing promoting activity than conventional root canal filling material compositions. Preferable compositions are (1) a composition further comprising a calcium hydroxide, (2) a combination composition of a paste A containing a higher fatty acid and rosin and a paste B containing magnesium oxide and a vegetable oil, and one or both of the paste A and the paste B comprise the lithium salt, and (3) a combination composition of a paste A and a paste B and hardens by mixing the paste A and the paste B, one or both of the paste A and the paste B comprise the lithium salt, one or both of the paste A and the paste B comprise a glass powder, the glass powder contains calcium oxide and silicon dioxide in a total amount of 50 to 100% by weight relative to a total amount of the glass powder, and in the glass powder, a weight ratio of the calcium oxide to the silicon dioxide (calcium oxide:silicon dioxide) is 6:4 to 3:7.

Abstract: The present invention provides a novel isolated mesenchymal cell population of highly purified osteoprogenitors (HipOPs) that can be used in the formation of bone tissue and methods for isolating and using same.