半导体激光美白程序对牙髓组织及P物质影响的研究

The effect of semiconductor laser on pulp tissue and substance P expression during whitening procedure

目的:观察使用半导体激光美白程序对大鼠牙髓组织的影响及其牙髓组织中P物质(SP)表达的变化。方法:将3月龄雄性SD大鼠100只随机分为3组,A组(n=10)不作任何处理,直接取样;B组(n=40)用半导体激光美白程序中的7 W、20 Hz、15 s连续频率、C组(n=40)用7 W、20 Hz、30 s、1/2间断频率照射其上颌第一、二磨牙,于术后即刻、1 d、3 d、7 d时B、C组各处死大鼠10只;取上颌骨制作组织切片,用HE染色、免疫组化染色观察牙髓组织的变化及牙髓组织中SP表达的变化。结果:B、C各组的牙髓组织充血情况均高于A组(P<0.05),B组高于C组。B、C各组牙髓组织中的P物质表达水平均高于A组(P<0.05),且从即刻组开始升高,3 d组达最高,然后开始降低;同时段内B组的SP水平高于C组(P<0.05)。结论:半导体激光美白程序连续频率的刺激性高于间断频率,激光照射后3 d内会使牙髓组织中疼痛递质的表达升高。

AIM： To observe the expression of Substance P （S P ） in dental pulp tissue after semiconductor laser treatment for whitening. METHODS： 100 male SD rats aged 3 months were randomly divided into a normal con-trol group（n = 10, group A） , continuous - wave semiconductor laser group （group B, n=40） ,and pulse generation laser group （ group C, n =40）. In group A, all rats were directly sacrificed. In group B and C, maxillary first and sec-ond molars of all rats were respectively irradiated by continuous and pulsing semiconductor laser at a frequency of 7 W, 20 Hz, 15 s. The rats were killed immediately after treatment, at day 1 , day 3 and day 7 after treatment respectively （n = 10）. Histological sections of maxillary first and second molars were stained with HE and IHC respectively. RESULTS ： Group B and C presented higher degree of hyperemia in pulp than that in group A, group B showed even higher degree of hyperemia than group C. The expression of SP in pulp tissue in group B and C was higher than that in group A（P 〈0. 05 ） . The level of SP started to rise immediately after irratiation and reached the highest level at day 3 , and then decreased. At the same time, the SP level in group B was higher than that in group C （ P 〈 0 . 05 ） . CONCLUSION： Continuous -wave laser is stronger than pulse laser in the stimulation of pulp tissues. Laser irradia-tion can cause increased pain transmitter SP expression in the pulp tissue within 3 days after irradiation.