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Biomedical subjects

E L Pashley

Publications and source records attributed to E L Pashley.

30 records · Page 2Linked to original sources
PubMed1988

Comparison of in vivo vs. in vitro bonding of composite resin to the dentin of canine teeth.

Dogs were utilized in a study to compare the bond strengths of dentin bonding agents made to dentin in vivo and then again in vitro in the same teeth 30 min, one day, one week, and one month post-extraction. No statistically significant differences were observed between bonds made in vivo and those made in vitro at any time period. Contamination of the dentin surfaces with blood or saliva lowered the bond strengths, but these could be restored to control values by re-surfacing of the dentin with a bur.

Animals↗
PubMed1983

An experimental study of hematoma formation after arterial and venous puncture.

Hematoma formation following the puncture of femoral veins or arteries of dogs was determined using mercury-filled strain gauges. Arterial bleeding always produced a hematoma. The duration of the swelling was prolonged if heparin was previously administered. Bleeding from the femoral vein did not produce a hematoma unless venous pressure was elevated by venous occlusion. The results indicate that the rapidly developing hematoma occasionally seen in dental practice following the administration of local anesthetics is of arterial origin.

Animals↗
PubMed1981

Pressures created by dental injections.

In routine dental practice, anesthetic solutions are injected into tissue sites of widely different distensibilities, under a variety of pressures. The purpose of the present study, during simulated dental practice, was to determine the maximum injection pressures obtained by clinicians during injections in dogs. Regular aspirating dental syringes were used together with dental anesthetic cartridges filled with isotonic saline. Maximum operator injection pressures ranged from 330 to 660 psi (17,061-34,122 mmHg). Those injection sites that were least distensible gave the highest maximum injection pressures: interosseous (21,559 mmHg); incisive papilla (18,224 mmHg); periodontal (17,630 mmHg); hard palate (11,322 mmHg); and intrapulpal (8918 mmHg). More distensible tissue sites gave much lower pressures. The data indicate that dental injection pressures vary widely from several hundred mmHg to several hundred psi, depending on the clinician's physical effort and the distensibility of the tissue.

Anesthesia, Dental↗
PubMedDate not supplied

Dentin permeability: sealing the dentin in crown preparations.

Provisional restorations of full crown preparations may permit more microleakage of bacteria and their products than the final castings do. However, most investigations of the sealing qualities of cemented castings have reported that they too permit dye leakage. One approach to the problem is to seal the dentin with dentin bonding agents at the completion of the crown preparation. This study evaluated the ability of six different dentin bonding agents to seal the dentin of crown preparations of human teeth in vitro using two independent techniques. The first technique quantitated fluid filtration across dentin before and after treatment with dentin bonding agents at one hour, one day, one week, and one month and after thermocycling. The second method measured silver nitrate penetration of the thin veneers of dentin bonding agents into the dentin. Both methods correlated well with each other. The best seals were obtained with Prisma Universal Bond 2 or Superbond powder plus liquid. The worst seals were found using Gluma and Superbond liquid only. Clearfil PhotoBond, Amalgambond, and Scotchbond 2 gave intermediate results. Although the dentin bonding agents tend to accumulate on chamfers, thereby increasing their thickness to 200-300 microns, the method looks promising as a simple way to protect the pulp from the consequences of microleakage.

Analysis of Variance↗
PubMedDate not supplied

Amalgam buildups: shear strength and dentin sealing properties.

The retentive strength and sealing properties of amalgam buildups were compared in vitro in three groups of specimens. All teeth were prepared with flat, nonretentive surfaces. In the first group, the amalgam buildups were retained by four self-threading Minim pins. In the second group, retention was provided by a circumferential slot prepared in the dentin just inside the DEJ. The third group utilized an adhesive resin for retention. Dentin permeability was measured as a hydraulic conductance before and after placement of the amalgam buildups and before and after thermocycling. All methods of retention sealed dentin very well even in the absence of cavity varnish. The 90 degree retentive strength was: pins, 10.3 +/- 0.9 MPa; slots, 4.1 +/- 0.5 MPa; resin, 3.1 +/- 0.8 MPa (mean +/- SEM).

Adolescent↗
PubMedDate not supplied

Protective effects of cavity liners on dentin.

Smear layers are very soluble in acidic solutions. Removal of smear layers increases dentin permeability and the potential for pulpal irritation. In this study, smear layers were treated with either saline, Barrier, Copalite, LC-Scotchbond, Hydroxyline, or DDS 1 & 2 to determine how well they protected the dentin from subsequent acid attack with 37% phosphoric acid for two minutes. Using both SEM and permeability measurements, the materials were ranked from least to most effective as: Saline less than Barrier = Copalite less than Hydroxyline = Scotchbond = DDS 1 & 2.

Acid Etching, Dental↗