Influnce Of Nd: YAG Laser On The Level Of Aspartate Aminotransferase And Alkaline Phosphatase In Gingival Crevicular Fluid

Objective: To compare the clinical effect of the treatment by Nd:YAG laser combined with scaling and root planing or scaling and root planing alone for chronic periodontitis, and to investigate the change of levels of aspartate aminotransferase(AST) and alkaline phosphatase(ALP) in gingival crevicular fluid(GCF) before and after treatment. The effect of Nd:YAG on therapy of periodontitis and rehabilitation of periodontium was evaluated, and the basis was provided for to choose effective treatment for periodontitis .Methods: Seven systematic healthy adults, or 4 males and 3 females, with moderate to advanced chronic periodontitis were selected in this study. Qualified subjects were required to have at least one periodontal pocket with probing depth(PD) deeper than 4mm on each quadrant in oral cavity.This was a randomized,split mouth design study.The 45 target sites were divided into one of the three groups at random as follows:A)scaling and root planing alone;B)scaling and root planing first,followed by Nd:YAG laser therapy(100mj,20HZ, 30s);C)Nd:YAG laser treatment first(100mj,20HZ,30s),followed by scaling and root planing.Each group was composed of 15 sites.Subsequently each patient was scheduled for the full-mouth supra-gingival scaling and oral hygiene instruction before baseline. Probing depth(PD) were measured at baseline, one week and biweekly after therapy for 8 weeks. GCF of all the target sites were taken for measuring the level of aspartate aminotransferase(AST) and alkaline phosphatase(ALP). Results: (1)At baseline, data of three groups were comparative and there were no statistically significant differences in Probing depth(PD),volumn of GCF and the level of two enzymes(AST,ALP) in GCF (P>0.05) at the sites tested in three groups. (2) A significant decrease was showed in Probing depth(PD) and volumn of GCF of the three groups compared to baseline(P<0.05), but there was no significant difference among three groups(P>0.05).(3) A significant decrease was showed in the level of GCF-AST and GCF-ALP of the three groups compared to baseline(P<0.05) on every checkup after therapy; When compared between groups, level of GCF-AST and GCF-ALP of group A and C significantly decreased more than that of group B(P<0.05) on week1,2 and 4 after therapy. GCF-AST and GCF-ALP of group A and B increased on week 6,which was still significantly lower than baseline(P<0.05). A prolonged decrease was showed in the level of GCF-AST and GCF-ALP of group C throughout the 8 weeks of observation.On week 6 and 8,the level of the two enzymes in group C was significantly lower than that in group A and B(P<0.05).Conclusions:(1) Under the condition of inflammation,GCF increased, and level of GCF-AST and GCF-ALT increased too. GCF-AST and GCF-ALT was correlated with the condition of periodontal inflammation, which could be the objective criterion to indicate condition of periodontal tissue and to judge the short-term effect of periodontal therapy. (2) Three kinds of treated methods could make the level of GCF-AST and GCF-ALT decrease and improve periodontal condition. (3) Nd:YAG laser irradition on the root surface of periodontal tooth before scaling and root planing reduced the level of AST and ALP in gingival crevicular fluid to a significantly lower level,which kept a prolonged decreasing tendency throughout the 8 weeks of observation.(4) The optical fiber of pulsed Nd:YAG laser was pliant and slender.It could get into the bottom of periodontal pocket easily and its energy could be adjusted in the threshold at ease.The application of Nd:YAG laser in clinic could obtain sound effects ,which could be a supplementary method to treat periodontitis and was to be with broad prospect in application.