低强度激光对大鼠实验性牙齿移动牙髓与牙周组织中P物质表达的影响

Effect on Dental Pulp and Periodontal Substance P Expression During Orthodontic Tooth Movement in Rats after Low Energy Laser Irradiation

目的观察低强度激光照射对大鼠实验性牙齿移动牙髓与牙周组织中P物质表达的影响。方法将45只Wistar大鼠随机分为9组,每组5只。其中1组为正常组(0h或0d组),不予任何处理。另8组给予牙齿移动处理,并按牙齿移动处理至处死的时间分为3h、6h、12h、24h、72h及7d、14d、21d组。牙齿处理方法为于左右侧上颌第一磨牙和切牙之间拴结镍钛闭合螺旋弹簧,力值为40g。安放镍钛螺簧后立即用He-Ne激光与CO2激光同时照射大鼠左侧第一磨牙的颊部(实验侧),He-Ne激光功率10mW,光斑直径1.2cm,照射距离100cm;CO2激光输出功率4W,光斑直径1.2cm,照射时间10min;右侧为对照侧。按设定时间将各组大鼠处死后,利用免疫组化ABC染色,结合计算机图像分析,测定0h、3h、6h、12h、24h、72h组大鼠实验侧相对照侧牙髓P物质免疫组化(SP-IR)灰度值,以及各组大鼠实验侧、对照侧牙周组织中SP-IR灰度值。结果实验侧牙髓中SP-IR免疫组化灰度值低于对照侧,以第12和24小时明显(P<0.01);实验侧牙周膜压力区SP-IR免疫组化灰度值7d明显高于对照侧(P<0.01);在14d时较高于对照侧(P<0.05)。实验侧牙周膜张力区SP-IR免疫组化灰度值在14d时较高于对照侧(P<0.05)。结论低强度激光照射对正畸初始牙髓中P物质的表达及牙周组织中P物质的表达均有影响。

Objective To investigate the effect on dental pulp and periodontal substance P expression during orthodontic tooth movement in rats after low energy laser irradiation.Methods Forty-five Wistar rats were chosen and divided into9groups according to experimental days for0h,3h,6h,12h,24h,3d,7d,14d and21d with5rats in each group.A NiTi coil spring with40g connected the maxillary upper first molar to the upper incisor and fixed bilaterally by a ligature wire.The left side served as control and the right side received as test one which was irradiatied by He - Ne laser and CO 2 laser.The dental pulp and periodontal SP-IR at test sides and control sides were stained by means of immunohistochemistry with the computer image analysis system.Results At experimental pressure sides,the pulp SP - IR was highly decreased at12h and24h(P<0.01),and the periodontal SP - IR was significantly elevated at7th day(P<0.01)and highly elevated at14th day(P<0.05)in comparison with the control ones.At tested tension sides,the periodontal SP - IR was highly elevated at14th day(P<0.05)when compared with the control ones.Conclusions Low energy laser could affect pulp SP expression during initial orthodontic tooth movement and promote periodontal tissue remodeling through the effects on SP - IR in periodontal ligament.