树脂修饰化玻璃离子托槽粘结剂粘结强度的体外研究

In Vitro Study of Shear Bond Strength with Resin-modified Glass Ionomer Cement for Bonding Orthodontic Brackets

目的:评估一种树脂修饰化的玻璃离子托槽粘结剂在牙面不同处理方式和环境下的两次粘结后的剪切强度情况。方法:将新近拔除的105颗上颌第一前磨牙随机均分成7组,按照说明书的要求完成托槽的粘结。对照组牙面用37%的磷酸处理后,用光固化复合树脂粘结剂(3M,Transbond XT)粘结。其它6组牙面分别在37%的磷酸、GC处理剂(GC Self-Conditioner)、和不做任何处理的条件下,分别在干燥和湿润的环境下用树脂修饰化的玻璃离子(RMGIC;Fuji ORTHO LC,GC Corporation,Tokyo,Japan)粘结,所有牙齿均选用同种托槽。托槽粘结24 h后,在万能测力机下以1 mm/min的速度卸载,并记录下数值。除去牙面和托槽底面多余粘结剂后,重复上述过程。每次卸载后检查牙釉质损坏情况。结果:对照组两次剪切强度有较小的差异,其它GC玻璃离子粘结剂组两次剪切强度没有统计学意义。GC粘结剂不做任何处理组在干燥和湿润的环境下其剪切强度存在明显的差异。干燥环境下,37%的磷酸和GC处理剂处理后,GC粘结剂组两次卸载后的牙釉质均出现不同程度的釉裂或釉质脱落。结论:这种树脂修饰化的玻璃离子粘结剂可以在多种条件下用于托槽的粘结。

Objective： To evaluate the shear bond strength（SBS） under different conditions of the bonded and rebonded orthodontic brackets with a resin modified glass ionomer cement （RMGIC）. Methods： A total of 140 premolar teeth were randomly divided into seven groups, and brackets were bonded according to the manufacturers＇ instructions. In control group, the teeth were etched using 37% phosphoric acid, and the brackets were bonded using a light - cure composite resin （3M Transbond XT） . The other groups were treated with 37% phosphoric acid, GC self- Conditioner （GC Corporation） and unconditioned respectively and bonded under both wet and dry conditions. The brackets of all groups, except control group ,were bonded using a resin -modified glass ionomer cement （RMGIC; Fuji ORTHO LC, GC Corporation, Tokyo, Japan）. The same bracket type was used in all groups. The teeth were debonded in shear mode using an universal testing machine at a crosshead speed of 1 mm/min. The shear bond strength was tested 24 hours after bracket bonding with the bonding/debonding procedures repeated again after the first debonding. The same bracket was rebonded on the same teeth after the removal of residual adhesive with micro - etching. Enamel fracture was examined also for each debonding. Re- suits ： A slight difference was observed in SBS between debonding 1 and debonding 2 of control group and no diffirence was observed between the other GC Fuji Ortho groups. A significant difference existed in SBS under wet and dry conditions in GC Fuji Ortho unconditioned group. Different degree of enamel fracture was seen in both 37% phosphoric acid and GC self - Conditioner conditioned GC Fuji Ortho debonding 1 and debonding 2 groups. Conclusion： This resin modified glass ionomer cement can be used to bond orthodontic brackets to enamel under different conditions.