Clinic of Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, Zurich,
Private practice, Andelfingen, Switzerland.
Caries Res. 2019;53(1):33-40. doi: 10.1159/000489133. Epub 2018 Jun 7.
The aim of this in vitro study was to investigate the impact of saliva on the abrasion of eroded enamel using two measuring methods. A total of 80 bovine enamel specimens from 20 bovine incisors were allocated to four experimental groups (n = 20 specimens per group). After baseline surface microhardness (SMH) measurements and profilometry all specimens were subjected to erosion (2 min, 1% citric acid, pH: 3.6, 37°C). SMH was determined again, and the depths of the Knoop indentations were calculated. Thereafter, specimens were incubated in human saliva (group 1 - no incubation/control, group 2 - 0.5 h, group 3 - 1 h, group 4 - 2 h) before toothbrush abrasion was performed. After final SMH measurements and profilometry, indentations were remeasured, and surface loss was calculated. SMH did not return to baseline values regardless of the length of saliva incubation. Further, an irreversible substance loss was observed for all specimens. With the indentation method, significantly (p < 0.05) more substance loss was found for controls (least square means ± standard error of 198 ± 19 nm) than for groups 2-4 (110 ± 10, 114 ± 11, and 105 ± 14 nm). Profilometric assessment showed significantly more substance loss for controls (122 ± 8 nm) than for group 4 (106 ± 5 nm). Intraclass correlation for interrater reliability between measurement methods was low (0.21, CI: 0.1-0.3), indicating poor agreement. Exposure of eroded enamel to saliva for up to 2 h could not re-establish the original SMH. The amount of measured substance loss depended on the measurement method applied.
本体外研究旨在使用两种测量方法探究唾液对酸蚀牙釉质磨损的影响。从 20 颗牛切牙中收集 80 个牛牙釉质标本，将其分为 4 个实验组（每组 20 个标本）。所有标本均进行酸蚀（2 分钟，1%柠檬酸，pH 值：3.6，37°C）前先进行基线表面显微硬度（SMH）测量和轮廓测量。再次测定 SMH，并计算努氏压痕的深度。此后，将标本在人唾液中孵育（第 1 组-不孵育/对照，第 2 组-0.5 小时，第 3 组-1 小时，第 4 组-2 小时），然后进行牙刷磨损。最终 SMH 测量和轮廓测量后，重新测量压痕，计算表面损失。无论唾液孵育时间长短，SMH 均未恢复至基线值。此外，所有标本均观察到不可逆的物质损失。使用压痕法，对照组（198 ± 19nm）的物质损失显著多于其他组（2-4 组：110 ± 10nm、114 ± 11nm 和 105 ± 14nm）（p < 0.05）。轮廓评估显示，对照组（122 ± 8nm）的物质损失明显多于第 4 组（106 ± 5nm）。两种测量方法之间的组内相关系数（ICC）为 0.21（CI：0.1-0.3），表明一致性较差。将酸蚀牙釉质暴露于唾液中长达 2 小时，无法恢复原始 SMH。测量物质损失的量取决于所应用的测量方法。
