Provided is a dental pretreatment material for dental tissue regeneration by use of dental pulp stem cells, particularly a dental pretreatment material effectively enabling dental tissue regeneration even by use of dental pulp stem cells of middle-aged or older individuals. The dental pretreatment material is characterized by comprising a serine protease, specifically trypsin. The dental pretreatment material comprising trypsin is used as an injection into a root canal before a root canal filling material comprising dental pulp stem cells and an extracellular matrix is inserted into the root canal as an attempt to regenerate a dental pulp and a dentin. The root canal filling material includes an ALK5 inhibitor, a CCR3 antagonist, or a CCL11 neutralizing antibody.