Int J Periodontics Restorative Dent. 2023 Oct 24(7):s18-s25. doi: 10.11607/prd.6528. Epub 2023 Jun 9.
To evaluate the effects of desensitizing MI Varnish (GC America) applied before or after bleaching on the mineral component of enamel and surface topography.
The coronal portions of 10 freshly extracted bovine teeth were segmented for a total of 40 specimens. Enamel specimens obtained from each tooth were randomly divided into four groups (n = 10): Group A = no bleaching; Group B = bleaching with 40% hydrogen peroxide (HP); Group C = MI Varnish applied before bleaching; and Group D = MI Varnish applied after bleaching. The calcium (Ca) and phosphorus (P) levels of the specimens in each group were determined by energy dispersive spectroscopy (EDS). Morphologic changes were observed using scanning electron microscopy (SEM). One-way ANOVA and Tukey HSD tests were used for statistical analyses (α = .05).
The mean Ca content of Group B was significantly lower than those of Groups A, C, and D (P < .05). The mean Ca content of Group C was significantly lower than that of Group A (P < .05). There was no significant difference in Ca content between the other groups (P > .05). The mean P content of Group A was significantly higher than those of Groups B to D (P < .05). There was no significant difference in P content between Groups B to D (P > .05).
Application of MI Varnish before or after in-office bleaching was effective in reducing mineral loss. However, applying MI Varnish after bleaching was more effective.
评估 MI 釉质黏结剂（GC America）在漂白前后应用对牙釉质矿物质成分和表面形貌的影响。
从 10 颗新鲜拔出的牛牙的冠部分离出 10 个部分，共获得 40 个样本。从每个牙齿获得的釉质样本被随机分为四组（n = 10）：组 A = 无漂白；组 B = 用 40%过氧化氢（HP）漂白；组 C = 在漂白前应用 MI 釉质黏结剂；组 D = 在漂白后应用 MI 釉质黏结剂。用能量色散光谱仪（EDS）测定各组标本的钙（Ca）和磷（P）含量。用扫描电子显微镜（SEM）观察形态变化。采用单因素方差分析和 Tukey HSD 检验进行统计学分析（α =.05）。
组 B 的平均 Ca 含量明显低于组 A、C 和 D（P <.05）。组 C 的平均 Ca 含量明显低于组 A（P <.05）。其他组之间的 Ca 含量无显著差异（P >.05）。组 A 的平均 P 含量明显高于组 B 至 D（P <.05）。组 B 至 D 之间的 P 含量无显著差异（P >.05）。
在诊室漂白前后应用 MI 釉质黏结剂可有效减少矿物质损失。然而，在漂白后应用 MI 釉质黏结剂更有效。
