S-PRG配合歯磨剤とNaF配合歯磨剤およびNaFワニスとのin vitroにおける象牙質透過性の比較

S-PRG-based toothpastes compared to NaF toothpaste and NaF varnish on dentin permeability in vitro.

抄録

目的:

S-PRG フィラーを配合した 5 種類の歯磨剤と NaF 歯磨き剤および NaF 歯磨き剤の象牙質透水係数（Lp）に対する影響を解析すること。

OBJECTIVES: To analyze the effect of 5 toothpastes containing different percentages of S-PRG fillers compared to NaF toothpaste and NaF varnish on the dentin hydraulic conductance (Lp).

方法:

第三大臼歯から象牙質円板（厚さ 1.0±0.2 mm）を切り出し，Flodec を用いて Lp 値を評価した．試料は7群（n=8）に分けた．Lpの最小値（スメア層）と最大値（酸エッチング後）を記録した．また，0wt％，1wt％，5wt％，20wt％，30wt％のS-PRG歯磨剤，NaF歯磨剤，NaFワニスで処理した後，Lpを評価した．歯磨きは，15 秒間ブラッシングし，1 分間沈降させた後，脱イオン水ですすぐことによって塗布した．NaFワニスは4分間塗布した後，プローブで除去した．試料はクエン酸（6%、pH2.1、1分）にさらされ、最終的なLpが記録された。すべての製品のpHを記録し（n=3），各群の標本をLaser Scanning Confocal Microscopy（LSCM）により分析した．データは2元配置反復測定ANOVAとポストホックボンフェローニ（a=0.05）に供された。

METHODOLOGY: Dentin disks (1.0±0.2 mm thickness) were cut from third molars, and their Lp values were evaluated using Flodec. The specimens were allocated into 7 groups (n=8). The minimum (smear layer) and the maximum (after acid etching) Lp values were recorded. Lp was also assessed after treatment with either a 0wt.%, 1wt.%, 5wt.%, 20wt.%, or 30wt.% S-PRG toothpaste, a NaF toothpaste, or a NaF varnish. Toothpastes were applied by brushing for 15 s, allowing it to settle for 1 min, and rinsing with deionized water. The NaF varnish was applied for 4 min and was removed with a probe. Specimens were exposed to citric acid (6%, pH 2.1, 1 min) and their final Lp was recorded. The pH of all products was recorded (n=3) and specimens from each group were analyzed by Laser Scanning Confocal Microscopy (LSCM). Data were subjected to 2-way repeated measures ANOVA and post-hoc Bonferroni (a=0.05).

結果:

5wt.% S-PRG 歯磨き粉，NaF 歯磨き粉，NaF 歯磨き粉で最も Lp が減少した．しかし，5wt.%，20wt.%および30wt.%のS-PRGを含む歯磨きは，すべての歯磨きに類似していたが，NaFワニスとは異なっていた．侵食後，NaFワニスを除き，全群でLpの最大値を回復した．LSCMでは，5%，20%および30%のS-PRG配合歯磨剤とNaF歯磨剤で処理した試料の表面に沈着物が認められた．また，NaFワニスではさらに多くの沈着物が観察された．侵食試験後、すべてのグループで沈着物は減少した。

RESULTS: The highest Lp reduction was noticed for the 5wt.% S-PRG toothpaste, NaF toothpaste, and NaF varnish. However, the toothpastes containing 5wt.%, 20wt.%, and 30wt.% of S-PRG were similar to all toothpastes but differed from the NaF varnish. After erosion, all groups retrieved their maximum Lp values, except for the NaF varnish. The LSCM evidenced deposits on the surface of specimens treated with 5%, 20%, and 30% S-PRG-based toothpastes and NaF toothpaste. Even more deposits were observed for the NaF varnish. After the erosive challenge, the deposits were diminished in all groups.

結論:

S-PRG 5wt%、20wt%、30wt%のフィラーを配合した歯磨剤は、NaF歯磨剤と同様の挙動を示し、侵食試験後においても、S-PRGはNaF歯磨剤と同様の挙動を示した。NaFワニスはLpの減少をより促進したが，その効果は侵食後にも減少した．

CONCLUSION: Toothpastes containing 5wt.%, 20wt.%, and 30wt.% of S-PRG fillers behaved similarly to a conventional NaF toothpaste, even after an erosive challenge. The NaF varnish promoted better reduction of the Lp, but its effect was also diminished after erosion.