Gupta Sanjay Prasad, Shrestha Basanta Kumar
Orthodontics and Dentofacial Orthopedics Unit, Department of Dentistry, Tribhuvan University Teaching Hospital, Institute of Medicine, Kathmandu, Nepal.
Clin Cosmet Investig Dent. 2018 Apr 10;10:61-67. doi: 10.2147/CCIDE.S155829. eCollection 2018.
To determine and compare the shear bond strength (SBS) of bracket-bonding system cured with light-emitting diode (LED) and halogen-based light-curing unit at various polymerization times.
Ninety six human maxillary premolar teeth extracted for orthodontic purpose were divided into four groups, according to the light-curing unit and exposure times used. In the halogen group, the specimens were light cured for 20 and 40 seconds. In the LED group, the specimens were light cured for 5 and 10 seconds. Stainless steel brackets were bonded with Enlight bonding system, stored in distilled water at 37°C for 24 hours and then submitted to SBS testing in a universal testing machine at a crosshead speed of 0.5 mm/minute. Adhesive remnant index (ARI) was used to evaluate the amount of adhesive remaining on the teeth determined by stereomicroscope at 10× magnification.
The highest mean SBS was obtained with the halogen 40 seconds (18.27 MPa) followed by halogen 20 seconds (15.36 MPa), LED 10 seconds (14.60 MPa) and least with LED 5 seconds (12.49 MPa) group. According to analysis of variance (ANOVA) and Tukey's multiple-comparison test, SBS of halogen 20 seconds group was not significantly different from halogen 40 seconds group, LED 5 seconds group and LED 10 seconds group, whereas halogen 40 seconds group was significantly different from LED 5 seconds and LED 10 seconds group. The method of light curing did not influence the ARI, with score 2 being predominant.
Polymerization with both halogen and LED resulted in SBS values that were clinically acceptable for orthodontic treatment in all groups. Hence, for bonding orthodontic brackets, photoactivation with halogen for 20 seconds and LED for 5 seconds is suggested.
测定并比较在不同聚合时间下，使用发光二极管（LED）和卤素灯固化单元固化的托槽粘结系统的剪切粘结强度（SBS）。
九十六颗因正畸目的拔除的人类上颌前磨牙，根据所使用的光固化单元和照射时间分为四组。在卤素灯组中，样本分别光固化20秒和40秒。在LED组中，样本分别光固化5秒和10秒。使用Enlight粘结系统粘结不锈钢托槽，在37°C蒸馏水中储存24小时，然后在万能试验机上以0.5毫米/分钟的十字头速度进行SBS测试。使用粘结剂残留指数（ARI）通过10倍放大的体视显微镜评估牙齿上残留的粘结剂数量。
卤素灯40秒组获得的平均SBS最高（18.27兆帕），其次是卤素灯20秒组（15.36兆帕）、LED 10秒组（14.60兆帕），最低的是LED 5秒组（12.49兆帕）。根据方差分析（ANOVA）和Tukey多重比较检验，卤素灯20秒组的SBS与卤素灯40秒组、LED 5秒组和LED 10秒组无显著差异，而卤素灯40秒组与LED 5秒组和LED 10秒组有显著差异。光固化方法不影响ARI，主要评分为2分。
卤素灯和LED聚合均产生了临床上正畸治疗可接受的SBS值。因此，建议粘结正畸托槽时，卤素灯照射20秒，LED照射5秒。
