| 1. | Ion objective : to investigate effect of nd : yag laser irradiating root canals on periapical tissue . methods : three minipigs were used in this study , deciduous premolars were opened , pulps were extracted , root canals were enlarged , then irradiated with nd : yag laser 30s and filled conventionally . the changes of periapical tissue were observed after 1 , 3 , 7 and 15 days . results : after one day , periapical tissue showed enlargement and engorgement of blood vessel and a few of leukocyte , the changes were more serious than in control . after 3 and 7 days , there were minor reactions in periapical tissue and same as the control group . after 15 days , periapical membrance in most specimens was normal . slight inflammatory reaction was found in the test group as same as in control group . conclusion : there was little damage to periapical tissue with the laser irradiation 目的:观察激光在根管内照射后对根尖周组织的作用.方法:选3只小型猪,全麻下将乳前磨牙开髓、抽髓,根管扩大后,激光照射30秒,做常规根管充填.对照组为常规根管充填. 1天、 3天、 7天和15天后观察根尖周组织的变化.结果:激光照射后1天,根周膜血管充血、轻度炎症,对照组只有根尖周膜充血.激光组组织反应比对照组稍重.激光照射后3天和7天,少数病例根周组织有轻度的刺激与对照组的病理表现相近.激光照射后15天部分标本根周膜正常,部分标本有轻度炎症反应,与对照组结果基本相似.结论:本激光照射条件对根尖周组织没有明显损伤作用,可供临床应用时参考 |