This study evaluated the effect of addition of the activated charcoal to different formulations of calcium hydroxide on dentin microhardness of endodontically treated teeth. Ninety one freshly human extracted single rooted teeth were selected. The samples were cleaned and shaped and classified according to the type of the dressing into five groups; Group 1; (21 samples) dressed with calcium hydroxide paste with Iodoform (Metapex) (META, Chungcheongbuk-do, Korea), Group 2; (21 samples) dressed with conventional calcium hydroxide with saline (GAMA dental lab, Cairo, Egypt). Group 3; (21 samples) dressed with calcium hydroxide paste with Iodoform mixed with activated charcoal (Eucarbon Sedico, Cairo, Egypt) and Group 4; (21 samples) dressed with conventional calcium hydroxide and activated charcoal with saline and Group 5; Control group (undressed). The samples were further classified according to the observation time into: Subgroup A; (7 samples) after two weeks. Subgroup B; (7 samples) after one month and Subgroup C; (7 samples) after two months. The microhardness measurements were performed using a Vickers Microhardness Tester (Model HVS-50, Laizhou Huayin Testing Instrument Co., Ltd. China). The results showed that there was a continuous decrease in the values of dentin microhardness by time however the samples with activated charcoal showed higher mirohardness over the tested periods. It was concluded that the addition of activated charcoal to the calcium hydroxide compounds can decrease the softening effect of different formulations of calcium hydroxide on the root canal dentin.

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Aim of the study: This study evaluated the effect of obturation technique on the fracture resistance of endodontically treated teeth obturated with bioceramic sealers compared to resinbased sealers.Methods: Ninety-one (n=91) freshly human extracted single rooted teeth were selected. The samples were biomechanically prepared and classified according to the obturation technique and type of the sealer used into five groups as follows: Group 1 (n=21) obturated with cold lateral compaction technique using gutta-percha and AD-seal sealer (Meta Biomed, Korea). Group 2 (n=21) obturated with warm vertical compaction technique using gutta-percha and AD-seal sealer. Group 3 (n=21) obturated with cold lateral compaction technique using gutta-percha and MTA filapex sealer (Angelus, Brazil). Group 4 (n=21) obturated with warm vertical compaction technique using gutta-percha and MTA filapex sealer. Group 5 (n=7) Control group (unobturated). The samples were further classified according to the observation time into: subgroup A (n=7) evaluated after one week, subgroup B (n=7) evaluated after two weeks and subgroup C (n=7) evaluated after one month. Samples were loaded vertically after obturation using Universal Testing Machine until fracture.Results: MTA filapex group showed higher fracture resistance values than the other groups with no significant difference. No significant difference was found between the subgroups evaluated at different time intervals. Conclusion:The technique of root canal obturation didn't significantly affect tooth fracture resistance at different time intervals.

Introduction: Creation of a sterile space is impossible in infected root canals, using mechanical preparation alone due to the complication configuration of radicular canal systems. Nearly half of the radicular canal dentine were left unprepared during the mechanical preparation with traditional stainless steel hand instruments and endodontic instruments.Aim; Evaluation of the outcome of numerous irrigating solutions used as final irrigation on the depth of sealer penetration into dentinal tubules.Methods: Two different endodontic sealers Bioceramic sealer and Resin sealer were used with four different irrigating solutions (Sodium hypochlorite, Chlorhexidine digluconate, Chiostan nanoparticles, Bio pure MTAD). GROUP 1: 5 ML of 2 % of naocl were used as a final irrigant for 1 min. GROUP 2: 5 ML of 2% chlorhexidine were used as a final irrigant for 1min. GROUP 3: 5ML of 0.2% of chitosan nanoparticles were used as a final irrigant for 1 min. GROUP 4: 5ML of MTAD were used as a final irrigant for 1 min. Depth of sealer penetration into dentinal tubules was evaluated after samples preparation using confocal laser microscope analysis. Results:Comparison between different sealers of all irrigants in the coronal section was performed by using Independent T-test which revealed that MTA fill apex was significantly higher than AH plus as P < 0.05 in NaoCl. Conclusion:MTA Fill apex sealer exhibited a significantly greater dentinal penetration than AH plus sealer irrespective of the final irrigation protocol.