Introduction:The use of chelating agents removes smear layer, increasing the access of irrigants to allow disinfection, and also reduces microhardness. Microhardness is an indirect evidence of mineral changes in dentin. Its reduction facilitates the instrumentation throughout the canal but, it may weaken the root and increases permeability of dentin. Therefore, finding a biocompatible chelating agent with better chelating ability is mandatory.Objective: To evaluate the effect Phytic acid (IP6) with different concentrations and ethylene diamine tetra-acetic acid (EDTA) solution on microhardness of radicular dentin. Materials and method:This study was conducted on 30 single rooted permanent maxillary anteriors. Teeth were instrumented using rotary files and irrigated in between using 2ml 2.5% NaOCl, then were sectioned longitudinally into halves giving 60 specimens that were embedded in acrylic resin leaving the dentin exposed. After polishing, the microhardness values of the untreated dentin 2 Alexandria Dental Journal. Volume XX Issue X.were recorded by Vicker's microhardness tester. The root halves were divided into 4 groups composed of 15 samples each and immersed for 5 minutes with one of the chelating solutions, Group I: Immersed in 10ml of (IP6) 0.5% followed by 10ml of 2.5% (NaOCl), Group II: Immersed in 10ml of (IP6) 1% followed by 10ml of 2.5% NaOCl, Group III: Immersed in 10ml of 1.5% (IP6) followed by 10ml of 2.5% NaOCl, Group IV: Immersed in 10ml of 17% EDTA solution followed by 10ml of 2.5% NaOCl. Then microhardness values were recorded, and calculation of the difference between baseline values and post-application values were calculated.Results: Tested chelators reduced microhardness of the dentin. 17% EDTA reduced the microhardness more significantly than 0.5%, 1% and 1.5% IP6. Conclusion:Using IP6 with different concentrations had less detrimental effect on dentin microhardness than EDTA.

Platelet rich fibrin in pulp revascularization of non-vital immature teeth.

INTRODUCTION: Non-surgical endodontic treatment is the best way to re-establish sound periapical tissues after reinfection or inefficient treatment of a previously obturated teeth due to apical or coronal leakage. It requires regaining the accessibility to the root canal system by removing the initial root canal filling, more cleaning, and reobturation. THE AIM OF THE STUDY: Is to compare the cleaning productivity of the XP Endo Finisher R (XPR) and the Endo Activator (EA) after retreatment using the scanning electron microscope (SEM). MATERIAL AND METHODS: This study was performed on forty-five mesiobuccal canals of mandibular first molars. All teeth were obturated then retreated using D-Race rotary files. Teeth were haphazardly divided into three groups according to the cleaning method used: Group (1): XPR. Group (2): EA. Group (3): control group (no final cleaning). All the teeth were sectioned longitudinally and canal cleaning ability was assessed by the SEM. Data were statistically analyzed using Chi-Square and Kruskal Wallis tests. RESULTS: Significant differences in the smear layer and debris removal between both XPR and EA groups and the control group were detected (P<0.05). CONCLUSIONS:The XPR and the EA are both efficient in removing the debris and the smear layer after retreatment. Moreover, the XPR performed better than the EA. None of the investigated techniques were able to totally remove the filling material.

INTRODUCTION: Debridement of the root canal system is essential for endodontic success. Traditional instruments alone cannot sufficiently clean root canals. There must be an effective delivery system. OBJECTIVES: was to compare the cleaning efficiency of XP-endo Finisher and the EndoActivator using the scanning electron microscope. MATERIALS AND METHODS Sixty human mandibular first premolars with single oval canals were used in this study. Teeth were instrumented using One-Shape file. Teeth were then randomly divided into three parallel groups (n=20) according to the agitation method used; Group I: XP-endo Finisher. Group II: EndoActivator. Group III: both XP-endo Finisher and EndoActivator. Teeth were sectioned longitudinally and assessed by the scanning electron microscope using the five-score debris and smear layer indices. Data were analyzed using Kruskal-Wallis, Friedman, and Dunn-Bonferroni tests. RESULTS: No significant differences were found between XP-endo Finisher and EndoActivator in debris and smear layer removal. In the middle segment, each of the XP-endo Finisher and EndoActivator revealed significantly lower debris scores than both together (P<0.05). In the coronal and apical segments the three groups equally cleaned debris (P>0.05). In smear layer removal, significant differences were found in both the coronal and apical segments between each one of the XP-endo Finisher and EndoActivator compared to both together (P<0.05). While in the middle segment, there were insignificant differences between the three groups in smear layer removal (P>0.05). The apical segment was more efficiently cleaned from debris and smear layer than the other segments in all groups. CONCLUSIONS: Irrigation of root canals using XP-endo Finisher and EndoActivator solely was more effective in the removal of debris and smear layer than both used together. The apical third was more efficiently cleaned from debris and smear layer than the other segments.

INTRODUCTION: Successful treatment of a root canal aims for removal of microorganisms from the canal. Therefore, intraradicular removal of the smear layer is a remarkable measure for long-established endodontic success. AIM OF THE STUDY: to assess Alizarin dye penetration into dentinal tubules following Q-Mix, apple vinegar, and 17% ethylenediaminetetraacetic acid (EDTA) under confocal laser scanning microscope (CLSM). MATERIALS AND METHODS: Thirty extracted single-canaled mandibular premolars went through decoronating to 15 mm length to undergo cleaning and instrumentation. Then, they were allocated at random into three groups based on the final rinse used: Group I: 10 ml of 17% EDTA for 1 minute, Group II: 10 ml of apple vinegar for 1 minute, and Group III: 10 ml Q-MIX for 1 minute. All root canals were irrigated by 5ml Sodium hypochlorite labeled with Alizarin red. Samples were horizontally sectioned and evaluated under CLSM at distinct canal levels. Data were analyzed using (Kruskal Wallis and Fried a ) Te . RESULTS: The three tested groups showed no statistically significant difference with p> 0.05. Regarding the coronal and middle thirds of EDTA, ACV, and Q-Mix groups, most of the specimens recorded score 3 (less than 50% of the whole number of dentinal tubules were penetrated with the dye) while the specimens of apical thirds recorded score 2 (traces of the dye could be seen along the internal canal surface). CONCLUSIONS: Q-Mix, Apple vinegar, and EDTA promoted the penetration through dentinal tubules in the coronal and middle sections superior to the apical section of the root canal.