Yu Ollie Yiru, Mei May Lei, Zhao Irene Shuping, Lo Edward Chin-Man, Chu Chun-Hung
Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
Materials (Basel). 2017 Oct 27;10(11):1245. doi: 10.3390/ma10111245.
This study evaluated the effects of fluoride on subsurface enamel demineralization induced by two commonly used chemical models. Forty-eight enamel blocks were demineralized at pH = 5.0 by an acetate buffer (Group 1), a lactate buffer (Group 2), an acetate buffer with 0.02 ppm fluoride (Group 3) and a lactate buffer with 0.02 ppm fluoride (Group 4) at 25 °C for 3 weeks. The surface destruction percentage (SDP), mineral loss and lesion depth of the blocks were studied using micro-computed tomography. An elemental analysis of the enamel surface was evaluated using an energy-dispersive X-ray spectroscopy. Surface micro-hardness was determined by the Knoop Hardness Test. The mean lesion depth of Groups 1 through 4 were 134.1 ± 27.2 μm, 96.1 ± 16.5 μm, 97.5 ± 22.4 μm and 91.1 ± 16.2 μm, respectively ( < 0.001; group 1 > 2, 3 > 4). The SDPs of groups 1 through 4 were 7.8 ± 8.93%, 0.71 ± 1.6%, 0.36 ± 1.70% and 1.36 ± 2.94% ( < 0.001; group 1 > 2, 3, 4). The fluoride in mean weight percentages of groups 1 through 4 were 1.12 ± 0.24%, 1.10 ± 0.20%, 1.45 ± 0.40% and 1.51 ± 0.51%, respectively ( < 0.001; group 3, 4 > 1, 2). The mean Knoop hardness values of groups 1 through 4 were 27.5 ± 13.3, 39.7 ± 19.3, 73.6 ± 44.2 and 91.0 ± 57.2, respectively ( < 0.001; group 4 > 3 > 2 > 1). The chemical model using an acetate buffer solution created significantly deeper zones of subsurface demineralization on enamel than the lactate buffer solution. An acetate buffer may damage the enamel surface, but the surface damage can be prevented by adding fluoride.
本研究评估了氟化物对两种常用化学模型诱导的牙釉质表层下脱矿的影响。48个牙釉质块在25℃下，通过醋酸盐缓冲液（第1组）、乳酸盐缓冲液（第2组）、含0.02 ppm氟化物的醋酸盐缓冲液（第3组）和含0.02 ppm氟化物的乳酸盐缓冲液（第4组）在pH = 5.0的条件下脱矿3周。使用微型计算机断层扫描研究了这些牙釉质块的表面破坏百分比（SDP）、矿物质流失和病变深度。使用能量色散X射线光谱对牙釉质表面进行元素分析。通过努氏硬度测试确定表面显微硬度。第1组至第4组的平均病变深度分别为134.1±27.2μm、96.1±16.5μm、97.5±22.4μm和91.1±16.2μm（P<0.001；第1组>第2组，第3组>第4组）。第1组至第4组的SDP分别为7.8±8.93%、0.71±1.6%、0.36±1.70%和1.36±2.94%（P<0.001；第1组>第2组、第3组、第4组）。第1组至第4组的氟平均重量百分比分别为1.12±0.24%、1.10±0.20%、1.45±0.40%和1.51±0.51%（P<0.001；第3组、第4组>第1组、第2组）。第1组至第4组的平均努氏硬度值分别为27.5±13.3、39.7±19.3、73.6±44.2和91.0±57.2（P<0.001；第4组>第3组>第2组>第1组）。与乳酸盐缓冲液相比，使用醋酸盐缓冲液的化学模型在牙釉质上产生的表层下脱矿区域明显更深。醋酸盐缓冲液可能会损害牙釉质表面，但添加氟化物可以防止表面损伤。
