Wiegand Annette, Schreier Monika, Attin Thomas
Clinic for Preventive Dentistry, Periodontology and Cariology, University of Zürich, Zürich, Switzerland.
Oper Dent. 2007 Nov-Dec;32(6):610-5. doi: 10.2341/06-171.
This in vitro study evaluated the effects of toothpaste fluoridation and toothpaste plus gel fluoridation and influence of the time period of fluoride gel application on the microhardness of bleached enamel.
Ninety bovine enamel samples were distributed among nine groups (A-I), each having 10 samples. Half of each surface was bleached with 10% carbamide peroxide gel (8 hours/daily) for 14 days, while the remaining surface was not bleached and served as the control. Groups A-H were fluoridated with toothpaste twice daily throughout the experiment (42 days) and assigned to fluoride gel treatment during the pre-bleaching period (14 days), during the bleaching period and/or during the post-bleaching period (14 days): A: prior, B: during, C: post, D: prior+during, E: during+post, F: prior+post, G: prior+during+post, H: no gel. Group I was neither fluoridated by toothpaste nor gel. The Knoop microhardness (KHN) of each specimen was determined at baseline, after pre-bleaching (day 14), after bleaching (day 28) and after post-bleaching (day 42). Statistical analysis of the percentage of change at baseline KHN was performed by ANOVA and t-test (p < 0.05).
Bleaching led to a significant decrease of KHN in Group I (unfluoridated) compared to Groups A-H, where microhardness did not fall below baseline values. Fluoridation treatment in Groups A-H increased microhardness in bleached and unbleached samples, but additional supplementation of fluoride gel in Groups A-G was not superior to toothpaste fluoridation only (H). After the post-bleaching period, the microhardness of the bleached and unbleached surfaces was not significantly different in Groups A-H.
Regular toothpaste fluoridation prevents microhardness loss due to bleaching treatment in vitro. The additional supplementation of fluoride gel did not enhance the beneficial effect of toothpaste fluoridation, and microhardness was not influenced by the time period of gel fluoridation.
本体外研究评估了牙膏氟化、牙膏加凝胶氟化以及氟凝胶应用时间段对漂白牙釉质显微硬度的影响。
将90个牛牙釉质样本分为9组（A - I），每组10个样本。每个样本表面的一半用10%过氧化脲凝胶漂白（每天8小时），持续14天，而另一半表面不进行漂白作为对照。在整个实验期间（42天），A - H组每天用牙膏进行两次氟化处理，并在漂白前期（14天）、漂白期和/或漂白后期（14天）进行氟凝胶处理：A：前期，B：期间，C：后期，D：前期 + 期间，E：期间 + 后期，F：前期 + 后期，G：前期 + 期间 + 后期，H：不使用凝胶。I组既不进行牙膏氟化也不进行凝胶氟化。在基线、漂白前（第14天）、漂白后（第28天）和漂白后（第42天）测定每个样本的努氏显微硬度（KHN）。通过方差分析和t检验对基线KHN变化百分比进行统计分析（p < 0.05）。
与A - H组相比，I组（未氟化）漂白导致KHN显著降低，而A - H组的显微硬度未降至基线值以下。A - H组的氟化处理增加了漂白和未漂白样本的显微硬度，但A - G组额外补充氟凝胶并不优于仅进行牙膏氟化（H组）。在漂白后期，A - H组漂白和未漂白表面的显微硬度无显著差异。
定期牙膏氟化可防止体外漂白处理导致的显微硬度损失。额外补充氟凝胶并未增强牙膏氟化的有益效果，且显微硬度不受凝胶氟化时间段的影响。
