Recalcification of Enamel Due to Laser Ablation

从亚微米颗粒的磷酸三钙（TCP）中提取TCP浆料，制备厚度为数十μm的TCP片材。用准分子激光、Q开关YAG激光和CO_2激光分别照射浆料和薄片包覆的脱质搪瓷针尖。我们研究了激光消融对牙釉质再钙化的影响。按照常规方法，我们制作了如下标本；将取出的约200 μm表面的恒牙抛光，并将其放入0.1 m乳酸缓冲液（0.3 mM -HAp, pH 4.5）中脱钙4小时。采用同一牙的两个牙釉质标本。其中一个试样在料浆或薄片上辐照（2个反应组），另一个试样在单料浆和薄片上不辐照（对照组）。部分标本用人工唾液浸泡4周，观察再钙化。在制备浆料时，TCP（平均粒径为0.41 μm）用纯净水配制至10-20%。在制作薄片时，将10%的TCP浆料、琼脂粉和马铃薯淀粉与纯净水混合，在85℃下加热溶解。然后将适量的溶液倒入塑料薄片中（厚度为30-60 μm），然后放置，干燥并切割成约5毫米见方。TCP片材的胶粘剂为5% CMC、0.3 mM-HAp溶液和75% HAp浆料。辐照的各种情况；准分子激光248nm (KrF)， Q开关YAG激光355nm（基波长1064nm的三次谐波产生），CO_2激光10600 nm，照射强度为2000次，70 ~ 150mj /cm^2, 0.8 ~ 1.0 W/lsec。在准分子激光/YAG激光70 ~ 100 mJ/cm^2和CO_2激光0.8 W/lsec的条件下，牙釉质尖浆状或片状发生激光烧蚀。激光烧蚀可明显增强TCP在脱钙牙釉质表面的黏附效果。在CO_2激光照射下，在浆体和薄片上形成激光烧蚀羽流。人工唾液对黏附浆料和片材的再钙化作用也较好。少

TCP slurry was extracted from tertiary calcium phosphate (TCP) of submicron particles, by which TCP sheets (dozens of μm in thickness) were made. The decalified enamel tip coated with slurry and sheets were irradiated by excimer laser, Q switch YAG laser and CO_2 Laser, respectively. We studied the effect of laser ablation on recalcification of enamel.According to the conventional method, we made specimens as follows ; an extracted permanent tooth that approximately 200 μm of the surface was removed was polished, which was decalcified for 4 hours into a 0.1 M-lactic acid buffer solution (0.3 mM -HAp, pH 4.5). Two enamel specimen of the same tooth were employed. One specimen was irradiated on slurry or sheets (2 reacted groups), and the other one was then treated by single slurry and sheets without irradiation (control group). Some specimens were immersed with artificial saliva for 4 weeks, whose recalcification was observed. In making slurry, TCP (a mean granular diameter of 0.41 μm) w … More as prepared to 10-20% with purified water. In making sheets, 10% TCP slurry, agar powder and potato starch mixed with purified water was heated at 85℃, and dissolved. An adequate amount of the solution was then poured into a plastic schale (30-60 μm in thickness), was then left, dried and cut to approximately 5 mm square. As adhesive agents for TCP sheets, 5% CMC, a 0.3 mM-HAp solution and 75% HAp slurry were employed. Each condition of irradiation ; 248 nm (KrF) of excimer laser, 355 nm (the 3rd harmonic generation of basic wavelength 1,064 nm) of Q switch YAG laser and 10,600 nm of CO_2 laser at 2000 shots of 70-150 mJ/cm^2 and 0.8-1.0 W/lsec were irradiated.Laser ablation occurred on slurry or sheets of enamel tip at 70-100 mJ/cm^2 of excimer laser/YAG laser and 0.8 W/lsec of CO_2 laser. The adherent effect of TCP in slurry or sheets for decalcified enamel surface was more strongly enhanced by laser ablation. In CO_2 laser irradiation, laser ablation plume was formed on slurry and sheets.Recalcification of adherent slurry and sheets was also more advanced by artificial saliva. Less