Nd:YAGレーザー照射およびAPFゲル処理後の乳歯エナメル質表面の形態と微小硬度の評価--in vitro試験

Evaluation of primary tooth enamel surface morphology and microhardness after Nd:YAG laser irradiation and APF gel treatment--an in vitro study.

抄録

目的:

レーザー照射とフッ素は永久歯のう蝕予防に用いられてきたが、う蝕になりやすい乳歯についてはほとんど行われていない。本研究の目的は、Nd-YAGレーザー単独照射およびNd-YAGレーザー照射前後のフッ化物局所処理併用による乳歯エナメル質の微小硬度変化を評価することである。

OBJECTIVE: Laser irradiation and fluoride has been used as a preventive tool to combat dental caries in permanent teeth, but little has been done for primary teeth which are more prone to caries. The purpose of this study was to evaluate microhardness alterations in the primary tooth enamel after Nd-YAG laser irradiation alone and combined with topical fluoride treatment either before or after Nd-YAG laser irradiation.

方法:

10本の小臼歯を切削し、対照群、Nd-YAGレーザー照射群、APF前のNd-YAGレーザー照射群、APF後のNd-YAGレーザー照射群に無作為に割り付けた。各群の微小硬度を評価した。表面形態学的変化はSEMを用いて観察した。

METHOD: Ten primary molars were sectioned and assigned randomly to: control group, Nd-YAG laser irradiation, Nd-YAG lasing before APF and APF followed by Nd-YAG lasing. The groups were evaluated for microhardness. Surface morphological changes were observed using SEM.

結果:

統計的比較が行われた。対照群のSEMではエナメル質表面は比較的平滑であり、レーシング群では微細なクラックや空隙が認められた。レーシング＋フッ化物群では、均一なコンフルエントな表面が認められた。フッ素＋レーザー照射群では、クラックの進展が顕著な不規則な輪郭が認められた。治療群の微小硬度に有意な増加が認められた。

RESULTS: Statistical comparisons were performed. The control group's SEM showed a relatively smooth enamel surface and lasing group had fine cracks and porosities. In the lasing + fluoride group a homogenous confluent surface was seen. In the fluoride + lasing group an irregular contour with marked crack propagation was noted. There was a significant increase in the microhardness of the treatment groups.

結論:

乳歯エナメル質へのNd-YAGレーザー照射とAPFの併用治療により、形態学的に硬化したエナメル質表面が得られ、う蝕原性攻撃に対する保護バリアとなりうる。

CONCLUSION: Nd-YAG laser irradiation and combined APF treatment of the primary tooth enamel gave morphologically hardened enamel surface which can be a protective barrier against a cariogenic attack.