ヒトの新鮮抜去歯に作った人工軟化象牙質と, 天然ウ蝕象牙質に塩基性フクシン・プロピレングリコール溶液による染色を施し, これによって染別された軟化象牙質の2層より採取された非脱灰および脱灰・リンタングステン酸染色切片を透過型電子顕微鏡で観察し, 次のような知見を得た。
1.健全象牙質に近接したウ蝕深部にはフクシンにほとんど染まらぬ第2脱灰層が存在し, この部のIntertublar dentinの無機結晶は健全部より移行的に減少していたが, 健全なコラゲン線維の上にその横紋構造に一致して規則的に配列していた。またPeritublar dentinの無機結晶も細管内壁から脱灰されて移行的に薄くなっていたが, 網状の有機基質とTomes線維は残存していた。
2.上記の第2脱灰層とウ蝕表層との問にはフクシンで鮮明に染まる第1脱灰層が存在した。この部のIntertublar dentinの無機結晶は第2脱灰層よりさらに減少し, 規則的な結晶配列は全くなくなり顆粒状の結晶として散在しており, コラゲン線維はバラバラになり, 横紋構造が不鮮明になってinterbandは消失していた。またPeritublar dentinの無機結晶は脱灰し尽くされ, ごく少数の顆粒状の結晶が散在しているにすぎず, 網状の有機基質およびTomes線維は全く存在していなかった。
3.天然ウ蝕の第1第2両脱灰層の移行部に認められた濃い自然着色層は, フクシンに染まりにくいために明確には染別しえなかったが, 電顕により無機および有機成分の性状を観察した結果, 上記の第1脱灰層に近い性質のものと判定された。

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The hypothesis that immunologic mechanism may play an important role in modifying the carious process was suggested by Blechman and Mori (1965). Presently an attempt was made to find the localization of salivary components, immunoglobulins, serum albumin and oral microorganisms in the human sound and carious dentin with a fluorescent antibody technique (Coons and Kaplan, 1950), an enzyme (peroxidase-labeled) antibody technique (Nakane and Pierce, 1967) and other staining techniques, as well as by microradiography.
Seventy freshly extracted sound and carious human permanent teeth (Table 1) were immediately put in cold 95% ethanol for fixation. These were divided into 2 segments. A segment from each tooth was hand polished to a thickness of about 70μ, cooled with cold saline and used for microradiographic studies.
Then it was demineralized in 0.5M pH7.4 EDTA (2Na-salt) at 4°C for 2-3 days. Another segment was demineralized in the same solution at 4°C for 7-14 days and embedded with paraffin. Microtome sections were made from each segment to a thickness of 7μ(Table 2).
Rabbit antiserums to human saliva, human immunoglobulins*, human serum albumin* and oral microorganisms were prepared. Fluorescein isothiocyanate**, tetramethylrhodamine isothiocyanate** and horseradish peroxidase*** were conjugated with the globulin fraction of rabbit antiserum. Commercially available fluoresceinlabeled anti human immunoglobulins serum** was also used. Control studies of specificity were made with labeled antiserum from which specific antibody had been absorbed by the addition of antigen.
When stained with labeled anti human saliva serum, labeled anti human immunoglobulins serum and labeled anti human immunoglobulins serum and labeled anti human serum albumin serum, specific reaction was usually observed in dentinal tubules (Figs. 6 and 7), dentinal fibers, predentin and the odontoblast layer of dentin (Fig. 8). These labeled antiserums also resulted in the most intense reaction in dentinal tubules beneath a translucent zone in the ground section, a radiopaque zone in microradiogram, of carious dentin (Figs. 10, 11, 14, 16, 17 and 18). Azure A eosin B stain, PAS stain and bromphenol blue stain produced a staining similar to that given by these labeled antiserums (Figs. 14, 15 and 19). Moreover, labeled anti human saliva serum resulted in diffuse reaction in soft carious dentin (Figs. 9 and 19). Although microorganisms were localized in dentinal tubules and the matrix of carious dentin (Figs. 20 and 21), no specific relation was observed between the localization of salivary components and that of oral microorganisms.
*Nutritional Biochemicals Co., Cleveland, Ohio, U. S. A.
**Baltimore Biological Laboratory, Baltimore, Maryland, U. S. A.
***Sigma Chemical Co., St. Louis, Missouri, U. S. A.

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