氟斑牙经脉冲Nd：YAG激光照射后贴面抗压强度观察

Observation on compressive strength of veneers on mottled teeth after pulse Nd：YAG laser irradiation

目的观察氟斑牙经脉冲Nd：YAG激光照射后贴面的抗压强度变化。方法取因各种原因而拔除的人上颌中切、侧切氟斑牙各30颗，每种切牙均分成试验组和对照组，每组15颗。试验组牙齿以脉冲Nd：YAG激光照射后．再以37％的磷酸酸蚀：而对照组牙齿只用37％的磷酸酸蚀，然后所有牙齿做树脂贴面，在Instron 4505电子万能试验机上进行压缩试验．测定切牙的试验组、对照组贴面的平均破坏载荷。结果试验组和对照组中切牙贴面平均破坏载荷分别为（0．342±0．053）、（0．289±0．041）kN，试验组明显高于对照组，两组比较差异有统计学意义（t=3．16，P〈0．05）；试验组和对照组侧切牙贴面平均破坏载荷分别为（0．321±0．041）、（0．208±0．032）kN，两组比较差异有统计学意义（t=7．66，P〈0．05）。结论脉冲Nd：YAG激光照射氟斑牙可以增大前牙贴面在功能运动中的强度，建议在临床中应用和推广。

Objective To analyze experimentally the compressive strength of veneers on mottled teeth after pulse Nd：YAG laser irradiation. Methods Sixty mottled teeth were extracted, including thirty maxillary central incisors and thirty maxillary lateral incisors and each were divided equally into two groups randomly （experimental groups and control groups）. The former were irradiated by pulse Nd：YAG laser and then etched by 37% phosphorus acid. The latter only etched by 37% phosphorus acid. All the teeth were restored by composite resin veneers and tested with Instron 4505 electronic testing machine. The average collapse loads of the veneers of incisors were tested. The maximal compressive loads of the samples were obtained, then the experimental results were analyzed. Results The average collapse loads of central incisors of test groups and control groups were （0.342 ± 0.053）, （0.289 ± 0.041 ） kN respectively, with a significant difference （t = 3.16, P 〈 0.05 ）. The average collapse loads of lateral incisors of test groups and control groups were （0.321 ± 0.041 ）, （0.208 ± 0.032）kN respectively. There was a significant difference when they were compared（t = 7.66, P 〈 0.05 ）. Conclusions The compressive strength of the veneers increases significantly when the mottled teeth are irradiated by pulse Nd：YAG laser. This method is worthy of recommending.