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Aim:To compare and evaluate the microhardness of enamel surface after the application of organic fluoride and inorganic fluoride dentifrices.Materials and Methods:Twenty freshly extracted premolars were collected and decoronation of all the teeth was done at cementoenamel junction. The crowns were sectioned mesiodistally into two halves with the help of diamond disc, and then the subsequent forty samples kept in 1% citric acid for the demineralization and divided into two groups by simple randomization, that is, Group A (inorganic sodium fluoride dentifrice) and Group B (organic amine fluoride dentifrice). They were treated using same protocol for 3 min, daily twice for 7 days. Those samples preserved in artificial saliva in between treatment. The enamel surface microhardness evaluated using Vickers hardness test at base level, after demineralization, as well as after remineralization. Statistical analysis of surface microhardness obtained at different stages done by Student's t-test and P < 0.05 was considered statistically significant.Results:The samples which were treated with sodium fluoride (Group A) could not restore the mean microhardness after treatment to that of preoperative level whereas amine fluoride (Group B) treated samples showed a statistically significant increase in mean surface microhardness from baseline.Conclusion:Organic fluoride (amine fluoride) remineralization was more effective in restoring enamel microhardness than inorganic fluoride (sodium fluoride) remineralization.

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Clinical significance: The apical extrusion of infected debris may have the potential to disrupt the balance between microbial aggression and host defense, resulting in incidents of acute inflammation. During preparation, irrigants and debris, such as bacteria, dentin filings and necrotic tissue may be extruded into the periradicular region leading to periapical inflammation and postoperative flare ups. Using an instrumentation technique that minimizes apical extrusion would be beneficial to both the practitioner and patient.The purpose of the study was to evaluate the weight of debris and volume of irrigant extruded apically from extracted teeth in vitro after endodontic instrumentation using four different rotary root canal instrumentation systems. Materials and methods:Four groups of each 20 extracted mandibular premolars were instrumented using one of the four systems: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland)), Hero-shaper (MicroMega, Besancon, France), RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) and K3 (SybronEndo, West Collins, CA). Debris and irrigant extruded from the apical foramen during instrumentation were collected in preweighed test tubes. Volume of irrigant extruded was noted. The containers were stored in incubator at 70° for two days to evaporate the moisture. Weight of dry debris was noted.Statistical analysis: Data was analyzed using Kruskall-Wallis and Mann-Whitney U test at a significance of 0.001. Results:The results indicated that all of the instrumentation systems tested caused measurable apical extrusion of debris and irrigants. Higher extrusion was observed with Protaper system which was statistically significant with Hero-Shaper, RaCe and K3 systems. There were no statistical differences between Hero-shaper, K3 and RaCe systems (p < 0.05). Conclusion:All instrumentation techniques apically extruded debris and irrigant. However, Hero-shaper, K3 and RaCe systems produced less extruded debris and irrigant than the Protaper system.

Aim and Objectives:To evaluate the apical fill in relation to apical leakage using three different obturating techniques – Single Cone, Ultrafil 3D, and lateral condensation.Materials and Methods:Sixty-six mandibular single-rooted premolar teeth were selected and were randomly assigned into three different groups of obturating techniques. The canals were prepared using 0.4/25 HyFlex CM (Coltene Endo) rotary system file and obturated with corresponding HyFlex CM Single Cone, Ultrafil 3D injectable technique, and lateral condensation. AH Plus (Dentsply, Detrey) has been used as the sealer. Twenty teeth each were assigned to the three experimental groups, and six teeth were used as positive and negative controls (3 in each group). Fluid filtration technique was used to determine the amount of apical leakage. The evaluation was done for 8 min at the interval of every 2 min. The same teeth were sectioned and a spectroscopic examination was done at 2 mm and 4 mm distance from the apices. The obtained data were statistically analyzed using analysis of variance test followed by post hoc turkeys test for multiple comparisons.Results:The mean apical leakage was maximum for lateral condensation when compared to the Single Cone and Ultrafil 3D. The amount of apical fill at 2 mm and at 4 mm was found to be more in the Single Cone than the other two techniques.Conclusion:The present study concluded that Single Cone obturation technique exhibited more gutta-percha filled area in the canal which led to decreased apical leakage than Ultrafil 3D and lateral condensation techniques, proving to be more effective in achieving a complete three-dimensional apical seal.