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Biomedical subjects

J F Watson

Publications and source records attributed to J F Watson.

At least 19 recordsLinked to original sources
PubMed1993

Resin bonding to various substrates.

The use of bonding adhesive techniques in dentistry in general and in esthetic dentistry in particular has expanded significantly. As techniques, materials, and results improve, adhesive procedures are substantially modifying many traditional approaches to treating dental problems. More esthetic and less invasive techniques are becoming routine as adhesive materials and techniques become tested and understood. This paper reviews several important areas that affect our understanding and application of adhesive dentistry. With the many material categories, materials in categories, and varieties of bonding surfaces, the subject is extremely complicated. An attempt has been made to divide the past year's literature into sections and to review each section as a separate component of this complex subject.

Acrylic Resins↗
PubMed1989

Comparison of casting ability of castable ceramic and type III gold.

This study compared the property of castability of a castable ceramic to an American Dental Association-certified type II casting alloy. A wax pattern was made with a manifold-type structure from which monofilament lines projected approximately 5 to 6 mm. The diameter of the nylon lines ranged from 132 micron to 1270 micron. Each pattern was invested and cast according to the manufacturer's specifications. Each casting was divested and measured for length of casting of the monofilament on a measuring microscope. The castable ceramic and type II gold cast completely at diameters of 1270 micron, and 724 micron, but only type II gold cast completely at the 152 micron and 132 micron diameters.

Ceramics↗
PubMed1985

Margin placement of esthetic veneer crowns. Part IV: Postoperative patient attitudes.

Ninety-one subjects with a total of 196 esthetic veneer crowns with visible gingival margins were surveyed. An esthetic analysis of crown margins showing with a normal smile and an exaggerated smile was performed and recorded. Patient satisfaction or dissatisfaction with the esthetic veneer crowns was assessed. The conclusions of this study support the results reported in the first three parts of this study, indicate that satisfactory results can be obtained on many individuals when the crown margins of esthetic veneer crowns are placed supragingivally, and support the philosophy that individual patient education and analysis are essential to the selection of optimum margin placement when esthetic veneer crowns are the treatment of choice.

Attitude↗
PubMed1984

Silver-plated dies. Part II: Marginal accuracy of cast restorations.

This laboratory study simulated actual clinical crown fabrication. Crowns were finished to the point of clinical delivery with stone and silver-plated dies made from representatives of the four major groups of elastomers. A clinically acceptable technique for judging crown margin accuracy was used, and numerical scores were assessed. Scores were analyzed statistically to compare die types, materials used, and types of discrepancies. Results of this study indicate the following information about the materials tested. The marginal accuracy of crowns fabricated on the silver-plated dies is statistically as accurate as that of crowns fabricated on stone dies in all cases and significantly more accurate in some instances. Silver-plated dies fabricated from Reprosil produced more accurate crowns than all other dies tested. Acceptable crown margins were obtainable from either stone or silver-plated dies when judged by clinical criteria. Silver-plated dies can be used without compromising crown margin accuracy.

Calcium Sulfate↗
PubMed1984

Silver-plated dies. Part I: Platability of impression materials.

The purpose of this study were to determine the acceptability of silver-plated dies made from representative brands of impression material from each of the four groups of elastomers and to determine the time required for initial plating of dies. Permlastic and Impregum , each previously shown to produce consistent silver-plated dies, were used for comparison. Representatives from the condensation-reaction and addition-reaction ( polyvinylsiloxanes ) silicones groups were tested until satisfactory materials were selected. Citricon and Xantopren - Optosil were tested in the former group and President and Reprosil in the latter. Conclusions include the following: All materials were flash-plated in 10 minutes or less. Acceptable silver-plated dies were obtained from Permlastic and Impregum . Acceptable silver-plated dies were obtained from condensation-reaction silicones with Xantopren - Optosil . From the polyvinylsiloxane group, Reprosil plated more consistently than President. Both produce acceptable dies. The technique modification studied was not effective for Citricon and President. The surface quality of silver-plated dies and the consistency of plating varies with materials. Individual impression materials should be tested prior to their routine clinical use with silver-plating procedures.

Dental Casting Technique↗
PubMed1981

Margin placement of esthetic veneer crowns. Part III: Attitudes of patients and dentists.

Attitudes of 396 subjects were surveyed concerning crown margin placement, and 112 dentists were surveyed regarding their treatment approach in respect to crown margin placement. The results of this study indicate that: 1. Routine subgingival margin placement of esthetic crowns may overtreat many patients. 2. Routine subgingival margin placement of esthetic crown is not always necessary. 3. Some patients may accept supragingival crown margins, even if they show. 4. A substantial group of patients may prefer optimum health potential over esthetics. 5. A thorough diagnosis should include analysis of patient's attitudes.

Attitude↗
PubMed1981

Margin placement of esthetic veneer crowns. Part II: Posterior tooth visibility.

The amount of posterior tooth visibility was analyzed in a population of 425 subjects. By scoring photographic data, the percentage of posterior teeth that could have a crown margin placed in their occlusal, middle, and gingival sections without showing were calculated. The results of this study indicate that: 1. For esthetic reasons, posterior margin placement should be handled on an individual basis. 2. The routine placement of either supragingival or subgingival margins for esthetics alone on posterior teeth may be over- or under-treating, respectively, a portion of the population. 3. A substantial percentage of the population studied had posterior gingival sections that were visible. A substantial percentage also had gingival sections that were not visible.

Bicuspid↗
PubMed1981

Margin placement of esthetic veneer crowns. Part I: Anterior tooth visibility.

The visibility of anterior teeth was studied in a population of 425 subjects. Scoring photographic data gave the percentages of anterior teeth that would not show a crown margin if it were placed in incisal, middle, or gingival sections. The results of this study indicate: their anterior teeth which would not show unless the lips were retracted.

Crowns↗
PubMed1979

Attitudinal differences of faculty and students regarding the care of special (handicapped) patients in a dental school clinic.

Faculty and students were surveyed as to their attitudes regarding the management of the special patient. This survey was completed after such a program was in existence for three years. Recommendations were made to better realize the overall goals of the program, especially that of encouraging the treatment of the special patients in the general practice of dentistry.

Attitude↗
PubMed1979

Evaluation of predictor variables for a self-instructional preclinical course.

Several studies have shown that the Dental Admission Test and predental grade point average have validity in predicting performance in dental school. The purpose of this two-year study is to compare these predictors with a manual skill exercise to determine their usefulness in predicting manual dexterity success in operative dentistry. Sophomore students were instructed to make preparations on an Ivorine block following imprinted outlines. Correlation to performance on laboratory examinations was computed. Results indicate the traditional predictors have limited usefulness in manual skill prediction while the Ivorine block exercise demonstrated consistent correlation over both years. The emphasis on manual dexterity in preclinical dental courses requires that appropriate variables be used in selecting students.

Achievement↗
PubMed1976

A method for the control of galvanism.

A simple method has been described for controlling the galvanic pain that occasionally follows the placement of amalgam restorations. The use of silver nitrate appears to be immediately effective in eliminating this annoying occasional problem.

Dental Amalgam↗
PubMed1972

Biologic activity of digoxin-specific antisera.

Digoxin-specific antibodies are capable of removing essentially all intracellular digoxin from rat renal cortical slices or from human erythrocytes. In removing digoxin from erythrocytes, these antibodies are capable of reversing an effect of the drug on cellular potassium transport. This study provides direct evidence that antibodies are capable of removing, and thereby reversing the biological effect of, physiologically active low molecular weight substances after they have been taken up by mammalian cells. This biologic property of digoxin-specific antibodies suggests that autidigoxin sera may prove useful in the reversal of digoxin toxicity. Rapid and essentially quantitative removal of digoxin from red cells by antibody is not accompanied by an immediate restoration of patassium influx to normal levels. Identification of the mechanism of this phenomenon may provide useful information concerning the mode of action not only of digoxin, but also of the cation transport system of human erythrocytes.

Animals↗