Study Of The Effect Of Carisolv In Root Canal Chemomechanical Preparation In Vitro

ObjectiveThe study was to investigate the effect of Carisolv as a chemical reagent in root canal chemomechanical preparation,compared with 3%Hydrogen Peroxide(H₂O₂)+ 2%Tosylchloramide Sodium or 2.5% Sodium hypochlorite (NaOCl) using UV-VIS Spectrophotomer and Scanning Electron Microscope (SEM).Methods1. Samples collection and storageCentral incisors of maxillary with single root canal which were extracted in clinic service were collected. The samples which were intact,normal,with the length of root canal more than 10mm,and with the apical foramina nearly the same(Initial Apical File were 15#) were stored in 0.9%Sodium Chloride.2. Treatment of the samplesAll the samples which had been removed off crowns and pulps were covered with wax twice except root canal orifices,then dyed with 2%methylene blue.After 72h,all the samples were cut at 10mm to the apical foramina.60 samples whose layer of dentin were dyed completely were selected.3. GroupingAll the samples were divided into 3 groups randomly,each group contained 20 samples. Samples in Group A were irrigated with Carisolv; Samples in Group B were irrigated with 3%H₂O₂+2%Tosylchloramide Sodium; Samples in Group C were irrigated with 2.5% NaOCl.4. Optical density measurement of methylene blue in irrigating solutionAfter treated with different reagents for 15min,all the root canals were prepared using the step-back technique,the Initial Apical File (IAF) were 15#,the Master Apical File (MAF) reached 40#.The optical density of methylene blue were measured with UV-VIS Spectrophotomer after preparation with each file.5. Observation with SEM5 samples of each group were selected randomly after root canal preparation. Root canal cleaning degree of different sections were observed and then scored with SEM under different magnifications.6. Statistical analysisAll the data were analysed by SPSS 11.5 statistical software. Statistical tests of optical density were performed by analysis of variance and Student Newman Keuls-q test; the relationship between file times and concentration of methylene blue was tested by Spearman rank correlation.The scores of SEM were tested by Kruskal-Wallis H test. Significance level:P<0.05 was considered statistically significant, P<0.01 was considered higher statistically significant.Results1. The comparation of the optical density of methylene blueThere were significant differences in the optical density between Group A and Group B (P<0.05).There was no significant difference in the optical density between Group A and Group C (P>0.05). In Group A, the differences in the optical density between the samples treated by 35# MAF and those treated by 40#MAF were significant (p<0.01).2. The relationship between concentration of methylene blue and file timesThe results of rank correlation between concentration of methylene blue and file times were r =0.919 of Group A, r =0.948 of Group B, r =0.926 of Group C(P<0.01). There was no significant difference in concentration of methylene blue between 5 file times and 6 file times in each group (P>0.05).3. Root canal cleaning degree results observed by SEMIn the case of the SEM magnification 2000,there was no significant difference in scores of SEM in each section between Group A and Group C (P>0.05),the dentinal tubules were open, shape was very regular,with little or no smear layer,the root canal cleaning degree was significantly better than that of Group B (P<0.05).In each group , the root canal cleaning degree of the coronal third and the middle third of root canal were better than that of the apical third (P<0.05). In the case of the SEM magnification 7500, only Group A could remove the smear layer and debris completely, without excessus demineralization.Conclusions1. In the process of root canal chemomechanical preparation,Carisolv was superior to 3%H₂O₂+2%Tosylchloramide Sodium,cleaning ability was as effective as 2.5% NaOCl.2. 35#MAF was recommended for the root canal chemomechanical preparation of single canal teeth with 15#IAF.More necrotic tissue was removed than 30#MAF.3. The result of SEM was coincided with the result of the optical density of methylene blue. Carisolv could remove the smear layer, keep the structure of dentinal tubules without unnecessary demineralization. Better cleaning effect could be found in coronal third and middle third of root canal than that of apical third.