应用龈沟液弹性蛋白酶评价正畸保持期牙周组织的改建状况

目的检测龈沟液中弹性蛋白酶（Elastase，EA）在正畸前、中、后以及保持各阶段的变化，探讨EA水平波动对保持期牙齿稳定性的提示意义。材料和方法以拔除四个双尖牙的病例为研究对象，从北京大学口腔医院正畸科门诊搜集分别处于正畸治疗前、治疗中关闭间隙、治疗结束、保持3—6个月、保持12个月五个阶段的病例，每组20例。以下切牙、拔牙间隙区牙齿为检测对象，提取龈沟液及记录临床检查指标，检测龈沟液中EA浓度。结果牙周临床检查指标（菌斑指数、牙龈出血指数）变化相似，在各阶段的变化无统计学意义。EA水平在治疗中关闭间隙阶段表现出明显的升高趋势，有统计学意义；治疗结束时EA水平仍高于治疗前；保持阶段呈缓慢下降的趋势，但保持一年后下切牙区EA水平仍高于治疗前。结论EA在正畸过程中及保持期的变化对牙齿的稳定状态具有提示作用。保持一年还不足以保证牙齿处于稳定状态。

Indication of GCF Elastase for Tooth Stability during Orthodontic Retention

Objective To investigate changes of elastase activity in gingival crevicular fluid （GCF） among different orthodontic treatment stages from pretreatment to retention as an indicator of periodontal remodeling activity. Materials and methods Four-premolar extracted cases were selected from Orthodontic Department of Peking University. Cases in time points of pre-treatment, space closure, post- treatment, 3-6 months of retention as well as 12 months of retention were grouped respectively. Each group was composed of 20 cases with 10 males and 10 females. Lower incisors and teeth mesial to extraction space were selected for GCF sampling and clinical examination. Results No statistically significant changes were found in periodontal index （plaque index, gingival bleeding index）. However, significant fluctuation of GCF elastase activity was indicated from pretreatment to post-treatment with a peak at the space closing stage. It was found that EA of post-treatment was still at a higher level than that of pretreatment, but it tended to decline in retention. However, after one year retention, the level of EA in lower incisor was still higher than that of pretreatment. Conclusions GCF could be considered as an indicator for tooth remodeling after orthodontic treatment. One-year retention isn＇t long enough for maintaining tooth stability.