漂白用ジェルの過酸化物濃度が色と歯質への浸透性に及ぼす影響について

Influence of Bleaching Gel Peroxide Concentration on Color and Penetration through the Tooth Structure.

抄録

目的・目標:

本研究の目的は、過酸化水素濃度が漂白効果と歯質への浸透性に及ぼす影響を評価することである。

AIM AND OBJECTIVE: The purpose of this study was to assess the effect of hydrogen peroxide concentration on the bleaching efficacy and penetration through the tooth structure.

材料と方法:

ウシの切歯から円筒形のエナメル質／象牙質の標本を100個入手した。表面を研磨し、サイズを標準化した。漂白用ジェルの過酸化水素の濃度に応じて5つのグループ（＝20）に分けた。酢酸緩衝液を入れた人工歯髄室に標本を置き，30分間漂白した（各10分を3回）。酢酸緩衝液のアリコートを採取し，分析用分光光度計で過酸化物濃度を測定した。ベースラインと漂白処置の7日後に、分析用分光光度計を用いて試料の色を分析した。色差は△式を用いて算出した。データは一元配置のANOVAとTukey's test（<0.05）で分析した。

MATERIALS AND METHODS: One hundred enamel/dentin specimens with cylindrical shape were obtained from bovine incisors. The surfaces were polished and the size standardized. They were divided into five groups ( = 20), following the concentration of hydrogen peroxide in the bleaching gels: 20, 25, 30, 35, and 40% (w/w). The specimens were placed over artificial pulpal chambers containing acetate buffer solution and bleached for 30 minutes (three applications of 10 minutes each). Aliquots of the acetate solution were collected, and the peroxide concentration was measured by an analytic spectrophotometer. The color of the samples was analyzed using a colorimetric spectrophotometer at the baseline and 7 days after the bleaching procedure. The color difference was calculated using the ∆ formula. The data were analyzed by one-way ANOVA and Tukey's test ( <0.05).

結果:

過酸化物濃度が20～30％のものは，高濃度のものに比べて漂白効果が小さかった( = 0.001)。また，過酸化物の浸透性は，より高濃度のジェル（35および40％）で有意に高かった（＝0.001）。

RESULTS: The peroxide concentrations of 20-30% showed smaller bleaching effect than the higher concentrations ( = 0.001). The peroxide penetration was significantly higher ( = 0.001) for the more concentrated gels (35 and 40%).

おわりに:

過酸化物濃度が高いほど漂白効果は高まるが，歯質への過酸化物の浸透性も高くなった。

CONCLUSION: The higher peroxide concentrations enhance the bleaching efficacy, but also increased the peroxide penetration through the tooth structure.

臨床的意義:

過酸化水素濃度の高いオフィス用漂白剤（35および40％）は，優れたホワイトニング効果を示す。しかし，歯髄組織への浸透性が高いため，歯髄組織への生物学的な悪影響が強まる可能性がある。この論文を引用するにはTorres CRG, Zanatta RF, Godoy MMM, .漂白ジェルの過酸化物濃度が色と歯質への浸透性に与える影響.J Contemp Dent Pract 2021;22(5):479-483.

CLINICAL SIGNIFICANCE: In-office bleaching gels with higher concentrations of hydrogen peroxide (35 and 40%) present superior whitening efficacy. Nevertheless, they might also intensify the negative biological effects on the pulpal tissue, since they exhibit increased penetration potential. How to cite this article: Torres CRG, Zanatta RF, Godoy MMM, . Influence of Bleaching Gel Peroxide Concentration on Color and Penetration through the Tooth Structure. J Contemp Dent Pract 2021;22(5):479-483.