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Biomedical subjects

Z Kasloff

Publications and source records attributed to Z Kasloff.

17 recordsLinked to original sources
PubMed1996

Antibacterial effects of amalgams on mutans streptococci in an in vitro biofilm test procedure.

Conflicting data continue to be presented in the literature regarding the antibacterial potential of various amalgam alloy compositions. The aim of the present study was to compare the antibacterial effects of 4 different amalgam samples on mutans streptococci using two in vitro test procedures. Glass and bovine enamel served as negative controls. The first test, one commonly used, consisted of immersing freshly prepared disks of the six materials in culture broth inoculated with mutans streptococci. Optical density measurements of the broth served to evaluate bacterial growth. This was followed by a biofilm technique which provided more intimate contact between the bacteria and specimen surfaces. With the exception of one high-copper lathe-cut amalgam, the first test revealed no antibacterial potential of the samples whereas the second test with the biofilm design elucidated significant differences in antibacterial potential between the amalgam alloy compositions and the controls. The biofilm technique, used in an in vitro test procedure, reflects the conditions of the oral environment more accurately than conventional test designs.

Animals↗
PubMed1991

Effects of warm air-drying and spreading on resin bonding.

The purpose of this study was to compare the effect on resin-to-enamel bonding produced by warm air from a hair dryer, and to correlate changes in resin bond strength with resin tag structure. Herculite-XR resin composite and Bondlite bonding resin were used. The three technique variables were the type of air used for drying, air dryer distance, and drying and spreading time. Control samples were dried and the bonding resin spread with a dental air syringe, whereas warm air from a hair dryer was used on the experimental samples. The bond strength (MPa) was determined in shear at a crosshead speed of 1 mm/min. Following bond strength evaluation, the teeth were immersed in 10% HCl for enamel dissolution and the resin tag structure was examined with the SEM. ANOVA analyses of shear bond strengths were performed. Warm air-drying and spreading for 15 seconds at 6 cm and 5 seconds at 6 cm respectively, produced statistically greater shear bond strengths (x = 20.4 +/- 4.4 MPa, P less than 0.05). The other drying time/distance combinations, including the control (x = 14.4 +/- 3.3 MPa), were not statistically different. Differences in resin tag structure were qualitatively evident under the SEM, with sharp tags produced by the warm air-drying and spreading techniques, compared to the blunt tags created by syringe air-drying and spreading. Warm air-drying and spreading significantly improved the bond strength. No apparent correlation exists between bond strength and tag length.

Air↗
PubMed1991

Effects of warm air-drying on intra-pulpal temperature.

This study was designed to determine what effects different warm air-drying conditions have on the intra-pulpal temperature (IPT), with or without chamber preparation and with or without an acid-etching treatment of the enamel. Four human maxillary centrals and four cuspids had lingual access openings prepared to accommodate a thermal sensor probe. Half of the specimens received a labial chamber preparation and half were acid-etched. All specimens were stored in water at 37 degrees C prior to testing. Labial aspects were positioned at 2 cm and 6 cm from the nozzle of a 500W hair dryer and IPTs were recorded after 15, 30, 45, and 60-second exposures. Exposure times for the acid-etched samples were modified to 10 seconds at 2 cm and 15 seconds at 6 cm. Results showed that for unetched teeth, increases in the IPT were greater at the 2 cm/15-second exposure (a 10.4-12.0 degrees C increase) than at the 6 cm/15-second exposure (a 3.9-6.6 degrees C increase). Even greater temperature changes were seen as the exposure times were increased to 30, 45, and 60 seconds. When the teeth were acid-etched, IPT rises of 5.6-10.1 degrees C and 5.8-8.7 degrees C were measured at 2 cm/10 seconds and at 6 cm/15 seconds, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Etching, Dental↗
PubMed1980

Microscopic study of smooth silver-plated retention pins in amalgam.

A silver-plating technique was developed in an effort to produce good mechanical bonding characteristics between stainless steel pins and amalgam. Metallographic microscope and scanning electron microscope (SEM) studies were made to assess the presence, or otherwise, of such a bond between (a) the silver layer plating and the surface of the stainless steel pins, and (b) and silver plating and the amalgam. Unplated stainless steel and sterling silver pins were used as a control and as a comparison, respectively. A "rubbing" technique of condensation was devised closely adapt amalgam to the pins. It is concluded that there is strong evidence for the existence of a good bond between the plated pins and amalgam. The mechanical performance of the bond is discussed elsewhere.

Chemical Phenomena↗
PubMed1980

Mechanical tests of smooth silver-plated retention pins in amalgam.

Retention and stress concentration factors can be improved if a good mechanical bond exists between smooth retention pins and an amalgam restoration. It is shown that, by silver-plating pins and by using a rubbing technique during condensation of the amalgam, a good mechanical bond is produced. Mechanical tests of this bond show that its shear strength is adequate to withstand the stresses likely to be produced by occlusal forces. The form of the tests was: (a) torsion, to demonstrate the performance of the bond in shear and (b) push-through, to provide stress distributions more closely allied to those found under clinical conditions. Plain stainless steel and plated stainless steel pins were compared for their performance and sterling silver pins were used for checking the validity of the torsion test methods. It is concluded from these tests that, with the plating and "rubbing" techniques mentioned, a good mechanical bond is produced which is likely to have value in clinical dentistry.

Dental Amalgam↗
PubMed1979

Axial stiffness of retention pins in human dentin.

Axial deflections of pins, anchored in specimens of human dentin by five different procedures, were measured by a specially constructed apparatus to an accuracy of 0.1 mu. Axial stiffness values calculated from these measurements were found to be significantly different for different methods of anchorage. Cemented pins displayed the lowest axial stiffness when compared with friction-locked and self-threading pins.

Acrylic Resins↗