ABSTRACT
The aim of this study was to, in vitro, evaluate and compare the apical sealing of a current endodontic sealer systems with that of AH26 sealer using the dye penetration technique. Twenty-five single rooted human anterior teeth were instrumented and randomly divided in two experimental groups of 10 each. Teeth in the first group were obturated with laterally condensed gutta percha cones and AH26 sealer and those in the second group were obturated with GuttaFlow; an injectable silicone based root canal filling system. Additional five teeth were used as control. The prepared teeth were suspended in 1% methylene blue dye at 37 [degree sign] C for a week, demineralized and dehydrated. Two independent examiners assessed the sealing efficacy of the prepared teeth using stereomicroscope with calibrated eye piece at x10. Statistical analysis was computed using SPSS 10.0 [Kruskal-Wallis test, P>0.05]. It was shown that GuttaFlow material system leaked less significantly than AH26 sealer [P<0.05]. GuttaFlow endodontic filling system is substantially effective in providing an adequate apical sealing against dye penetration
ABSTRACT
Objectives: this investigation determines the effect on contact angles of die stone obtained from elastomeric impressions materials after immersion disinfection
Materials and method: three representative brands of commonly used elastomeric impression materials along with four types of disinfecting agents were used in this study. Contact angle measurements after disinfection of elastomeric impressions were recorded as a measure of wettability, at three time periods [15, 30 and 120 minutes], using the photographic method
Results: immersion disinfection of these materials rendered a general significant decrease in the contact angle values [P<0.01] as a function of the disinfection time and the disinfecting a period of disinfection yielded the greatest decrease in contact angles data indicating the best wettability. Polyether impression material showed significantly [P<0.01] the least contact angle data when immersed in chlorine dioxide
Conclusion: immersion disinfection of elastomeric impressions decreased the contact angle values and disinfecting solution. hence, an increase in their wettability occurred. The contact angle values varied as a function of disinfection time and disinfecting agent type
ABSTRACT
To determine and compare the wettability of a denture base material by some soft-liners. The effect of various surface treatments of the selected denture base material was also evaluated. MATERIALS AND METHODS: A widely used denture base material and three newly marketed soft liners were investigated. The denture base material was either stored in artificial saliva or immersed in a disinfecting solution before and after surface treatments. The intaglio of the test denture base material was treated by airparticle abrasion, addition of a rebase material and application of soft liner primer or bonding agent. The photographic method of measuring the contact angles of each soft liner was utilized to detect variations in the wettability of the denture base material before and after its surface treatment. For each combination of soft liner and treatment, five readings were recorded. Data was statistically analysed by one way analysis of variance [ANOVA] and Student's t-test. RESULTS AND CONCLUSIONS: For all the soft liners, in general, air-particle abrasion of the denture base material significantly improved [p<0.001] its wetting as indicated by the recorded lower contact angle values. However, addition of the rebase material on the denture base surface had either no effect or increased the contact angle measurements except for Softliner stored in artificial saliva
Subject(s)
Wettability , Denture Liners , Dental Bonding , Dental MaterialsABSTRACT
The purpose of this study was to investigate the effect of autoclave sterilization technique on the structure and surface hardness of some hand-driven Ni-Ti endodontic files. MATERIALS AND METHODS: Two brands of Ni-Ti files were selected for this study. A total of 40 Ni-Ti #25 K-type files were divided into 2 groups of 20 each representing the two brands. Three subgroups of 5 each were sterilized in increments of two-cycle autoclave. One subgroup was retained as control. X-ray diffraction [XRD] and differential scanning colorimetric [DSC] techniques were utilized to characterize the files structure. The surface hardness of the tested files was also evaluated using Vickers microhardness tester. In addition, the file samples were chemically etched to reveal the changes in the microstructure using scanning electron microscope [SEM]. The obtained x-ray patterns and the DSC plots indicated that the analyzed files had the superelastic property with an austenitic-finish temperature [A] of about 50°C. In general, the temperature range and the phase transformation behavior were similar for the two tested files; before and after sterilization. In as-received condition, Vickers hardness values were 288'15 and 276'12 [kg/mm] for UlraFlex and Nitiflex files respectively. No significant differences [p>0.01] were found in the hardness values of files after sterilization. The microstructure of the tested files remained almost unchanged after being sterilized. CONCLUSIONS: The findings of this study indicate that the performed autoclave sterilization method does not significantly affect the structure, hardness or microstructure of Ni-Ti files. The detected slight variations between the two investigated file brands might be attributed to manufacturing processes and quality control procedures