ABSTRACT
Prior investigations have demonstrated dentinal cracking and chipping during ultrasonic preparation of the root-end. This study compared the frequency of cracking and chipping in two groups, cadaver and extracted teeth, using an indirect resin technique. Preparations were performed using either a 33 1/2 inverted cone bur in a high-speed handpiece, or with ultrasonics using a CT-2 tip at either high or low intensity. After replication of the root-end in epoxy resin, all teeth were evaluated for cracking and chipping under scanning electron microscopy. Statistical analysis using a general contingency table or ANOVA with Scheffé post-hoc analysis (p = 0.05) revealed no significant difference between all groups in terms of root-end cracking. In extracted teeth (n = 15), rotary instrumentation produced less chipping than either ultrasonic technique. Varying the intensity was not significant. There was no significant difference between any instrumentation group in cadaver teeth (n = 10) related to the amount of chipping.
Subject(s)
Apicoectomy , Dental High-Speed Equipment , Root Canal Preparation/standards , Tooth Root/pathology , Ultrasonic Therapy/instrumentation , Analysis of Variance , Cadaver , Coloring Agents , Dentin/injuries , Dentin/pathology , Epoxy Resins , Equipment Design , Humans , Methylene Blue , Microscopy, Electron, Scanning , Observer Variation , Replica Techniques , Root Canal Preparation/instrumentation , Tooth Root/injuriesABSTRACT
OBJECTIVES: The purpose of this study was to compare D-speed film, E-speed film, and the Soredex Digora system with respect to the detection of periradicular pathosis. STUDY DESIGN: Radiographic images of 100 cadaver jaws were made with E-speed film, D-speed film, and the Soredex Digora. Each set of 100 images was interpreted by four observers, with 30 days separating each of three viewing sessions from the next. The presence or absence of pathologic (inflammatory) periradicular bone resorption was determined by histologic examination of the samples. The observer performance was compared with the true histologic findings and evaluated with receiver operating characteristic and corrected receiver operating characteristic analysis. RESULTS: No statistically significant differences were found in diagnostic performance among the three radiographic techniques. In addition, no imaging technique was a good indicator of pathosis as determined by histologic analysis. CONCLUSION: Under the conditions of this study, it was determined that D-speed film, E-speed film, and the Soredex Digora were equivalent diagnostic imaging modalities with regard to the detection of pathologic periradicular bone resorption. No technique predictably indicated inflammatory resorption.
Subject(s)
Alveolar Bone Loss/diagnostic imaging , Periapical Diseases/diagnostic imaging , Radiography, Dental, Digital , Tooth Root/diagnostic imaging , X-Ray Film , Alveolar Bone Loss/pathology , Cadaver , Evaluation Studies as Topic , Humans , Observer Variation , Periapical Diseases/pathology , Periapical Periodontitis/diagnostic imaging , Periapical Periodontitis/pathology , ROC Curve , Tooth Root/pathology , X-Ray Film/classificationABSTRACT
This study determined the effect of handpiece pressure and speed on the intrapulpal temperature rise produced during finishing. Finishing was performed on a class V amalgam restoration with a brown rubber point. The remaining dentin thickness was standardized under the restoration at 2.0 mm. Finishing was done continuously for 60 seconds with temperature rises recorded at the dentin/pulp interface every 15 seconds. All finishing was done dry. Handpiece speed (rpm's) varied from 7000-15,000 rpm's and applied pressure from 20-60 gr force. Increases in either speed or pressure can produce significant intrapulpal temperature increases over these ranges. Doubling either one produces a 50% temperature increase during finishing. Finishing at 15,000 rpm's with 60 gr force is capable of producing damaging temperature rises at the pulp after only 15 seconds finishing time.
