ABSTRACT
INTRODUCTION: The aim of this study was to evaluate the effect of needle type and insertion depth, apical preparation size, and root canal curvature on irrigant extrusion by using a recently introduced method. METHODS: Sixteen human teeth with a straight root canal (group A) and 16 with a moderately curved root canal (group B) were sequentially prepared to sizes 25 or 35, .06 taper and mounted on a plastic vial filled with distilled water to simulate a periapical lesion. The vial was either closed or open to the environment. A point-conductivity probe was used to determine the volume of extruded irrigant into the vial. NaOCl was delivered by an open-ended or a closed-ended needle at 1, 3, or 5 mm short of working length. Results were analyzed by two 4-way mixed-design analyses of variance. The level of significance was set to P < .05. RESULTS: The open-ended needle extruded significantly more irrigant than the closed-ended. Irrigant extrusion decreased as needles moved away from working length or when the apical size was increased. Needle wedging increased extrusion, especially when an open-ended needle was used. Root canal curvature did not have a statistically significant effect on irrigant extrusion. CONCLUSIONS: Needle type, needle insertion depth, and apical preparation size had a significant effect on irrigant extrusion.
Subject(s)
Dental Pulp Cavity/anatomy & histology , Extravasation of Diagnostic and Therapeutic Materials , Needles , Root Canal Irrigants , Root Canal Preparation/methods , Analysis of Variance , Compliance , Equipment Design , Humans , Root Canal Irrigants/adverse effects , Root Canal Preparation/instrumentation , Tooth Apex/anatomy & histologyABSTRACT
INTRODUCTION: The aim of this study was to evaluate the push-out bond strengths of a new polyfiber post system and a fiber post that were adhesively luted with a dual-cure resin cement. METHODS: Forty single-rooted human maxillary teeth were sectioned below the cementoenamel junction, and the roots were endodontically treated. The roots were randomly divided into 2 groups of 20 specimens each according to the post type used: SpiraPost (group A; DMG, Englewood, NJ) and DT Light-Post Illusion X-RO (group B; Bisco Inc, Schaumburg, IL). All posts were cemented with dual-cure resin cement. Bonded specimens were cut into 1-mm-thick sections, and push-out tests were performed using a universal testing machine. All specimens were loaded until fracture, and the failure modes were evaluated with a stereomicroscope at 50× magnification. Representative specimens were analyzed by scanning electron microscopy. RESULTS: Push-out bond strength was significantly affected by the type of post (P < .05). In all root sections, the SpiraPost push-out bond strength values were significantly higher than that those of DT Light-Post Illusion X-RO (P < .05). Cohesive failure within the post was the most frequent type of failure for the SpiraPost system. CONCLUSIONS: In all root segments, the SpiraPost system provided significantly increased post retention compared with the fiber post.
Subject(s)
Dental Bonding , Post and Core Technique/instrumentation , Resin Cements/chemistry , Adhesiveness , Adult , Composite Resins/chemistry , Dental Materials/chemistry , Dental Prosthesis Design , Dental Prosthesis Retention , Dental Stress Analysis/instrumentation , Dentin/ultrastructure , Humans , Humidity , Materials Testing , Microscopy, Electron, Scanning , Middle Aged , Quartz/chemistry , Root Canal Preparation/methods , Self-Curing of Dental Resins , Stress, Mechanical , Surface Properties , Temperature , Time Factors , Tooth, Nonvital/pathologyABSTRACT
BACKGROUND: Translucency of dentine is the result of occlusion of the corresponding dentinal tubules by a mineral substance which has a refractive index similar to that of the rest of the dentine. CASE PRESENTATION: This case report describes the microradiographic features of an upper cadaveric canine. Transverse microradiograph is one of the methods assessing apical dentine translucency for various dental and medical reasons. CONCLUSION: Estimation of age using teeth structures may be of primary value in forensic dentistry, especially when soft tissues are severely destructed.
ABSTRACT
Scanning electron microscopy (SEM) and differential scanning calorimetric (DSC) studies were utilized to investigate surface and microstructure of two brands of rotary nickel-titanium (NiTi) endodontic instruments, in the as-received condition and after subjection to 1, 6, and 11 sterilization cycles. A total of 66 ProFile (n = 33) and Flexmaster (n = 33) files were examined. SEM observations indicated the presence of surface imperfections and adherent material in all new and sterilized instruments and an increase in surface roughness of the instruments that underwent multiple sterilizations. DSC measurements showed that the specimens of both brands, in the as-received condition and after 11 sterilizations, were completely austenite in the oral environment temperature, suggesting that they are capable of superelastic behavior in appropriate clinical conditions.
