【作者】 朱艳；

【导师】 刘新强；

【作者基本信息】 青岛大学 ， 口腔临床医学， 2006， 硕士

【摘要】 目的:通过离体牙模拟实验,探讨应用脉冲Nd:YAG激光照射对预防正畸托槽周围牙釉质脱矿的作用。并检测其对托槽粘接强度的影响,为此方法应用于临床的可行性提供理论依据。 方法:实验一 脉冲Nd:YAG激光照射对托槽周围釉质脱矿的影响。选用因正畸需要拔除的健康前磨牙50颗,随机分为五组,每组10颗。A₀组:为对照组,常规京津釉质粘接剂粘接金属托槽;A₁组:托槽粘接之前采用激光照射（不涂增效剂）;A₂组:托槽粘接之前采用激光照射（涂增效剂）;B₁组:托槽粘接之后采用激光照射（不涂增效剂）;B₂组:托槽粘接之后采用激光照射（涂增效剂）。通过脱矿实验检测脱矿液中的釉质钙溶出量,确定激光照射对托槽周围牙釉质抗酸性的影响及激光增效剂的作用。并用扫描电镜观察激光照射后离体人牙釉质表面的结构变化及釉质表面与粘接剂的结合情况。 实验二 脉冲Nd:YAG激光照射釉质对托槽抗剪切强度的影响。选用因正畸需要拔除的健康前磨牙60颗,随机分为六组,每组10颗。A₀-A₂组使用京津釉质粘接剂粘接金属托槽。A₀组:为对照组,常规粘接金属托槽;A₁组:托槽粘接之前采用激光照射;A₂组:托槽粘接之后采用激光照射。B₀-B₂组采用自酸蚀光固化粘接剂粘接托槽。B₀组:为对照组,常规粘接金属托槽;B₁组:托槽粘接之前采用激光照射;B₂组:托槽粘接之后采用激光照射。对所有实验样本进行了托槽抗剪切强度的测试,并对每个牙的粘接剂残留指数进行评定。更多还原

【Abstract】 Objective: The purpose of this study was to investigate the effects of pulsed Nd:YAG laser irradiation on resistance of enamel to demineralization during orthodontic treatment with fixed appliances, and also to evaluate the influence on shear bond strength of orthodontic brackets.Methods: Part one: Effects of Nd:YAG laser irradiation on resistance of enamel to demineralization. Fifty human posterior teeth with intact enamel were collected after extraction. They were randomly assigned to 5 groups of 10 each. The stainless steel brackets were applied to the teeth by the following methos. Group A0: The brackets were bonded with jing-jin enamel adhesive , following the manufacturer s instructions. The teeth in group A1 and group A2 were lased before bracket placement . The teeth in group B1 and group B2 were lased after bracket placement . The teeth in group A2 and group B2 were daubed with enhencer before laser treatment. Then all samples were immersed in lactic acid demineralization solutions and the concentration of Ca2+ dissolved in the solution was measured. The enamel surface morphology and the interface between emamel and adhesive were observed with the scanning electron microscope.Part two: Effects of Nd:YAG laser irradiation on shear bond strength of orthodontic brackets: Sixty human posterior teeth with intact enamel were collected after extraction. They were randomly assigned to 6 groups of 10 each. The stainless steel brackets were applied to the teeth by the following methos. In group A0-A2 The brackets were bonded with jing-jin enamel adhesive , following the manufacturers instructions. In group B0-B2 The brackets were bonded with self-etching primer +Transbond . The teeth in group A1 and group B1 were lased before bracket placement. The teeth in group A2 and group B2 were lased after bracket placement. The universal testing machine was used to test the shearbond strength of each tooth. After debonding, the adhesive remnant index was scored for each tooth.Results: 1. Laser irradiation decreased the Ca2+ concentration in demineralization solution (P<.05).2. The initiator plus laser decreased the Ca2+ release of enamel samples more than the laser only group (P<.05).3. No significant differences were found between the Ca2+ concentration in the group lased before bracket placement and that in the group lased after bracket placement.4. Laser treatment altered the enamel surface morphology observed with the scanning electron microscope.5. No significant differences were found between bond strengths of brackets in the group lased before or after bracket placement and that in the control group .6. There was no statistically significant differences between the mean ARI score for the treated groups.Conclution: 1. Laser irradiation may reduce the enamel decalcification that is often seen during fixed appliance treatment. The enamel surface can be lased before or after bracket placement.2. The initiator can increase the ability of Nd.YAG laser to confer demineralization resistance on enamel.3. Nd:YAG laser irradiation of enamel before bracket bonding has no effect on subsequent bond strength.Zhuyan (Orthodontics) Directed by: Liuxinqiang更多还原