ABSTRACT
This investigation compared the tensile bond strengths of a nickel-chromium-beryllium alloy etched electrolytically and etched with a commercially available chemical gel. The number of applications and the thermal conditions of the chemical etchant were varied to assess their influence on the composite-to-metal tensile bond strength. Etched metal cylinders were bonded end-to-end with a resin luting agent and were subsequently tested for tensile strength. Etch patterns, mean bond strengths, and mode of failure were recorded. Significant differences relating to the application number and the thermal conditions of the chemically etched specimens were noted.
Subject(s)
Acid Etching, Dental/methods , Chromium Alloys/chemistry , Dental Bonding , Electrolysis , Gels/chemistry , Resins, Synthetic/chemistry , Dental Stress Analysis , Microscopy, Electron, Scanning , Organic Chemicals , Sulfuric Acids/chemistry , Surface Properties , Temperature , Tensile StrengthABSTRACT
This study evaluated the treatment needs of 44 overdenture patients who had worn their dentures for at least 5 years. There were 135 abutment teeth involved, 35 in the maxillae and 100 in the mandible. Recall rates varied from a low of 27.6% to a high of 73.7%. The attrition rate was 20.5% after 5 years. The caries rate varied from a low of 2.7% to a high of 20.6%, and periodontal treatment was required by 94% of the subjects after 5 years. Only 39.4% of the subjects required adjustments, repairs, relines, or remakes of their overdentures during this time. The study showed that the success of overdentures depended on maintaining oral hygiene at an adequate level and at least yearly recalls to maintain gingival health.
Subject(s)
Dental Care , Denture, Overlay , Health Services Needs and Demand , Health Services Research , Adolescent , Adult , Aged , Dental Abutments , Dental Caries/therapy , Denture Rebasing , Female , Humans , Longitudinal Studies , Male , Middle Aged , Periodontal Diseases/therapySubject(s)
Dentifrices , Denture Cleansers , Denture, Partial, Removable , Chromium Alloys , Dental Alloys , Elasticity , Stress, Mechanical , Time Factors , VitalliumABSTRACT
The long-term dimensional stability of three non-aqueous elastomeric impression materials, a silicone, a polyether and a polysiloxane, were investigated. The testing apparatus was an A.D.A. specification No. 19 test block and mould. The impressions were measured by the use of a travelling stage reflecting microscope and a Quantimet 720 Image Analyzing computer at time zero and again at 4, 24 and 48 h, and at 1, 2, 3 and 4 weeks. Impressions poured immediately had the greatest accuracy for all the materials. The polysiloxane (0.025 mm) and polyether (0.033 mm) showed very little change in dimension after 4 weeks when compared to the test block. However, the silicone showed significant change at 4 h (0.14 mm) and 0.2 mm after 4 weeks. After 4 weeks the polysiloxane maintained the best surface detail, the polyether was adequate but the silicone lost much of its detail in as little as 24 h. The reasons for these findings are discussed.
Subject(s)
Dental Impression Materials , Polyvinyls , Rubber , Chemical Phenomena , Chemistry, Physical , Silicone Elastomers , Siloxanes , Surface Properties , Time FactorsABSTRACT
Data were examined concerning dental students' confidence in removable prosthodontic treatment and their attitudes toward elderly persons before and after a ten-week clinical prosthodontic rotation. The Rosencranz and McNevin Aging Semantic Differential (SD) Scale was used to measure attitudes regarding the elderly; another SD was designed to measure confidence in removable prosthodontics. Both student's attitudes toward elderly persons and their confidence in carrying out removable prosthodontic treatment improved significantly after the rotation; the greatest improvement occurred when students treated patients of all ages. There was a significant relationship between confidence in performing removable prosthodontic treatment and clinical grades, but not didactic grades.
Subject(s)
Aged , Attitude of Health Personnel , Denture Design , Students, Dental/psychology , Clinical Competence , Dentist-Patient Relations , Female , Humans , Male , Middle Aged , Prosthodontics/educationABSTRACT
1. Ninety-five percent of the variation in position of reattached lone standing incisor and premolar stone teeth was within the limits of physiologic tooth movement. 2. No significant differences resulted from the use of Class I or Class II stones, the technical experience of the operator, or the diameter of the neck of the tooth. 3. There were significant differences between Duco cement and Eastman 910 used between the tooth fragments, but none between Duco cement used between the tooth fragments and Eastman 910 used on the fracture line. However, with all three techniques, most of the changes were within the physiologic limits of healthy tooth movement.
Subject(s)
Dental Casting Technique , Models, Dental/standards , Adhesives , Calcium Sulfate , Dental Casting Investment , Dental Casting Technique/instrumentation , Dental Cements , Denture, Partial, Removable , Evaluation Studies as Topic , HumansSubject(s)
Calcium Sulfate , Water , Chemical Phenomena , Chemistry, Physical , Solutions , Time FactorsABSTRACT
The posterior palatal seal area is described and its anatomical borders are defined. The methods used to achieve a seal are (1) scraping the cast, (2) a selective loading impression technique, and (3) a physiological impression technique. Each method is described and its problems are discussed. It is believed by the authors that the physiological impression technique using wax requires the least amount of skill and experience to master competently.
Subject(s)
Denture Design , Denture, Complete, Upper , Dental Impression Materials , Dental Impression Technique , Humans , Palate/anatomy & histology , Palate, Soft/anatomy & histology , WaxesSubject(s)
Dental Impression Materials , Ethers , Silicone Elastomers , Sulfides , Adhesiveness , Elasticity , Models, Dental/standards , Polymers , Surface Properties , Time FactorsABSTRACT
The use of implanted and opposing magnets has been reviewed. A technique for the use of implanted magnets in the roots of endodontically treated teeth to aid the retention of overdentures has been described.
Subject(s)
Denture Retention , Denture, Complete, Lower , Denture, Overlay , Magnetics , Cementation , Dental Cavity Preparation , Denture Design , HumansABSTRACT
A technique that allows the master cast to be easily removed and attached to its split mounting index has been described. The cast is attached to its split mounting index by means of a machine screw and a disposable mounting stud.
Subject(s)
Dental Articulators , Dental Equipment , Denture Design , Models, Dental , Methods , Technology, DentalABSTRACT
A method for flasking removable partial dentures using a layered silicone rubber technique has been described. The silicone investment protects the stone teeth from fracture during removal of the removable partial denture from the investment. Then the occlusal changes can be accurately corrected following processing.