PROBLEM TO BE SOLVED: To obtain highly-accurate impression gypsum by controlling surface roughness of gypsum when gypsum is poured into a dental agar impression material, in regard to an agar impression material to be used in a dental cavity which is used for acquisition of impression in the dental cavity.SOLUTION: An agar impression material to be used in a dental cavity is used, which is produced via an alkali treatment step for adjusting an agar impression material to be used in a dental cavity containing agar and water so as to have pH in the range of 9-11 by a hydroxide of an alkali metal, and a neutralization treatment step for adjusting pH to be in the range of 5-8 by an acidic neutralizer.COPYRIGHT: (C)2013,JPO&INPIT【課題】歯科口腔内の印象採得の際に使用する歯科口腔内用寒天印象材に関する。歯科用寒天印象材は石こうを流し込んだ折に、石こうの面あれを抑制し、精度の高い印象石こうを得ることができる。【解決手段】寒天、水を含む歯科口腔内用寒天印象材をアルカリ金属の水酸化物にてpH9~11の範囲に調整するアルカリ処理工程、酸性中和剤にてpH5~8の範囲に調整する中和処理工程を経ることで作製された歯科口腔内用寒天印象材を用いることで解決される。【選択図】なし