不同处理方法的陶瓷托槽再黏结抗剪切强度比较

Comparison of shear bond strength of rebonded ceramic brackets with different methods

目的探讨不同处理方法对陶瓷托槽再黏结抗剪切强度的影响,为临床应用提供依据。方法选取2009年2—7月厦门市口腔医院正畸科患者中因正畸需要而拔除的健康双尖牙70颗,随机抽取30颗用于制备脱落陶瓷托槽,其余40颗用于黏结实验。将40颗用于黏结实验的牙随机分成4组(每组10颗):新陶瓷托槽组,烧灼处理组,喷砂处理组,硅涂层处理组。陶瓷托槽黏结于未经酸蚀处理的微湿的离体牙上,然后用去托槽钳小心取下,形成脱落托槽。分别对陶瓷托槽底面进行烧灼处理、喷砂处理、硅涂层处理;不同方法处理后,各组托槽底面常规涂硅烷偶联剂。每组离体牙经常规牙面处理后,分别黏结新陶瓷托槽及脱落后处理的陶瓷托槽,测定并比较各组抗剪切强度。结果新陶瓷托槽、烧灼处理、喷砂处理、硅涂层处理组抗剪切强度依次为(12.4733±3.4326)MPa、(7.2375±1.6914)MPa、(9.1612±1.3261)MPa、(13.1671±5.0392)MPa;烧灼组和喷砂组抗剪切强度与新托槽组和硅涂层差别有统计学意义(P<0.05),硅涂层组与新托槽组之间的差别无统计学意义(P>0.05)。结论陶瓷托槽经烧灼处理及喷砂处理后再黏结其抗剪切强度均有下降,硅涂层处理后其抗剪切强度与新托槽相近。

Objective The purposes of this study was to evaluate the effects of various surface conditioning methods on shear bond strength （SBS）of rebonded ceramic brackets.Methods A total of 70 human premolars extracted for orthodontic purpose were collected and divided randomly into two parts： one part （40 teeth）for the bond strength test ;the other part （30 teeth） for getting debonded ceramic bracksts. For experimental part： 40 human premolars were divided randomly into four groups（ 10 teeth in each group ） according to different treatment conditions：new brackets as controls, burning treatment, sandblasting, silica coating. Ceramic brackets were bonded to unetched and slightly wet tooth surfaces, then separated fi＇om the tooth surface easily with a tweezer with light pressure. The control group was treated with different methods ： burning treatment, sandblasting, silica coating.After that, a silane coupling agent was applied to different groups of bases.The teeth in each group were treated by conventional treatment, then were bonded with new brackets, burned brackets, sandblasted brackets, or siliac coated brackets. After 30 nfinutes, the samples were stored in distilled deionized water for 24 hours at 37℃ in an incubator. Shear force lest was performed and then the shear bond strength Was measured. Results The SBS of four groups were（12.4733±3.4326） MPa, （7.2375±1.6914）MPa, （9.1612±1.3261） M Pa, （13.1671±5.0392） MPa. The difference among all groups was of statistical significance, but there was no statistically significant difference between sandblasting group and silica coating group. Conclusion After burning and sandblasting, the shear bond strength of rebonded ceramic brackets decreases. Silica coating applications on debonded ceramic brackets base can produce bond strengths comparable with new brackets.