ABSTRACT
Boron implantation into Nitinol alloy has a potential for developing improved Nitinol root canal instruments with excellent cutting properties, without affecting their superelastic bulk-mechanical properties. The surface hardness of nickel-titanium (NiTi) alloy, also known as "Nitinol" (50 atm% nickel+50 atm% titanium), has been improved by ion-beam surface modification. With an implantation dose of 4.8 x 10(17) boron/cm2, a high concentration of boron (30 atm%) is incorporated into NiTi alloy by 110 keV boron ions at room temperature (25 degrees C). Boron-implanted and unimplanted (pure) Nitinol alloys show surface hardness of 7.6 +/- 0.2 and 3.2 +/- 0.2 GPa, respectively, at the nanoindentation depth of 0.05 micron. The ion-beam-modified NiTi alloy exceeds the surface hardness of stainless steel.
Subject(s)
Dental Alloys/chemistry , Dental Instruments , Nickel/chemistry , Root Canal Preparation/instrumentation , Titanium/chemistry , Boron/chemistry , Efficiency , Equipment Design , Hardness , Hardness Tests , Materials Testing , Surface Properties , X-Ray DiffractionABSTRACT
Samples of four brands of gutta-percha and the nine ingredients that make up one brand were studied in vitro to observe their interaction with the serum complement system, thus allowing for assessment of their possible inflammatory potential. Crossed immunoelectrophoresis of the third complement component was used as an indicator of complement activation. The four different brands of gutta-percha showed comparable complement activation as determined by C3 conversion. When the ingredients of one brand of gutta-percha were examined for complement-activating properties, major activities were associated with gutta-percha compound, agerite stalite-antioxidant, and titanium oxide food grade. The significance of the possible inflammatory potential of gutta-percha and its ingredients, as it relates to endodontic therapy, is discussed.
Subject(s)
Complement Activation/drug effects , Complement C3/immunology , Gutta-Percha/pharmacology , Root Canal Filling Materials/pharmacology , Humans , Immunoelectrophoresis , InflammationABSTRACT
Variations in same-size endodontic files (K-type, style B, stainless steel) were detected with a three-dimensional gauge. The variation between same-size files was within 3 mm. in most instances; however, variations from the smallest file in one size group to the largest file in the next size group was 5 mm. or more in many instances. Overall, about 74 percent of the variations came from the file itself. Suggestions concerning the use of the files are presented.
Subject(s)
Dental Instruments/standards , Root Canal Therapy/instrumentation , Stainless SteelABSTRACT
The use of surgical fistulation after endodontic therapy caused clinical problems for two patients. Only one patient was treated successfully for restoration of a molar; for the second, surgery was not advised. Analgesics and antibiotics may be better initial therapy than use of fistulation.
Subject(s)
Dental Fistula , Dental Fistula/etiology , Root Canal Therapy/adverse effects , Adult , Apicoectomy , Dental Fistula/diagnostic imaging , Dental Fistula/therapy , Female , Humans , RadiographySubject(s)
Composite Resins , Crowns , Denture Retention , Post and Core Technique , Adult , Calcium/metabolism , Dental Cavity Preparation , Dental Porcelain , Dental Pulp Cavity/anatomy & histology , Dentin/metabolism , Female , Gutta-Percha , Humans , Periapical Tissue/diagnostic imaging , Periodontal Diseases/diagnostic imaging , Radiography , Root Canal Obturation , Root Canal Therapy , Tooth Root/metabolism , Water/metabolismABSTRACT
A survey of undergraduate endodontic curricula in 67 United States and Canadian schools has been carried out. The response rate was 82%, with 2 of the 53 responses being incomplete. The major findings were as follows: 1. There was an extremely wide range in curriculum hours, but the average number of clock hours (46 hours) for the preclinical lecture and laboratory period compared favorably with the minimum recommended in 1965.' 2. The average of about six teeth treated during the clinical period also compared favorably with the minimum recommended in 1965.' 3. The average time required for each clinical case (11 hours per tooth) might suggest a critical reevaluation of teaching methods and philosophy.
