Effect of different irrigation porotocols on root dentine micro-hardness-An invitro study

Abstract

IIrrigation solutions used and time of use has a definite effect on the micro hardness & other physical properties of dentin which in turn have direct consequence on the longevity functional performance of root canal treated teeth. To evaluate the effect of different irrigation solutions on micro hardness of root dentin.Forty extracted single rooted lower premolars were used. After instrumentation all the root halves were randomly assigned into 4groups (n=10) and brought in contact with one of the following irrigants for 5 minutes. Group I: 10 ml of 5% Sodium Hypochlorite (NaOCl).Group II: 10 ml of 17% ethylene diamine tetra-acetic acid (EDTA) followed by 10 ml of 5% NaOCl.Group III: 10 ml of 5% NaOCl followed by 10 ml of 2% chlorhexidine digluconate (CHX).Group IV: 10 ml of 5% NaOCL followed by flush of 10 ml distilled water then by 10ml of 2% CHX. Dentin micro hardness was measured at baseline and after treatment to determine the change in micro hardness, using Vickers tester.Data was analyzed using following parametric tests t-test, ANOVA test and Post Hoc test. Group II ie final irrigation with EDTA showed the highest percentage decrease in micro hardness values, followed by group III, then group IV and the lowest was group I. All groups showed a significant difference between each other (P < 0.05), except group III and IV. The coronal third showed the highest percentage decrease with significant difference between apical and middle thirds (P < 0.05).EDTA with NaOCl causes greatest changes in dentine micro hardness, an intermediate flush with normal saline should be given for prevention of precipitation with NaOCl & CHX.