Biomedical subjects
Publications and source records attributed to J S Brudvik.
This study compared heat-cured acrylic resin denture baseplate distortions following a second heat cure used to add the denture teeth. The second heat cure was done with three different water-bath curing temperatures. The distortions were evaluated in three planes by use of a measuring microscope. Recorded distortions were not clinically significant.
During the metal finishing phase of removable partial denture construction, metal is removed from all aspects of the casting. The amount removed from areas designed to contact prepared surfaces of abutments is critical to the resulting fit of the partial. Castings were evaluated before and during finishing procedures to measure metal loss at the tooth-removable partial denture interface. Finishing and fitting techniques for controlling the loss of metal are presented.
Inlay-onlay composite resin restorations have been introduced to the profession as alternatives to amalgam and direct composite resins. Two-body wear testing was performed on three inlay-onlay resins and one direct composite resins using a machine designed to produce sliding wear. The composite resins were opposed by human enamel, type III gold alloy, and porcelain. Of the investigated materials, the homogeneously microfilled inlay-onlay material showed significantly less wear. The direct composite resin showed significantly the greatest wear. The hybrid inlay-onlay resins showed intermediate wear. The hybrid inlay-onlay resins and the direct composite (small particle, heavily filled) resin created wear tracks in the opposing surfaces while the homogeneous microfill inlay-onlay resin did not. The depth of the observed wear tracks in the opposing surface was sufficiently substantial to warrant further investigation into the wear of materials that oppose composite resin restorations.
This article has described a technique to achieve maxillary orthopedics for the infant with a bilateral cleft lip, protruded premaxilla, and intact palate. Both maxillary expansion and retraction of the premaxilla can be accomplished with the same prosthesis.
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This preliminary report has shown the following interesting points: (1) Measurements of tissue pressures beneath dentures are possible using the Sanborn 350 recorder. (2) Stable dentures produce high pressures on the supporting tissues and transmit these pressures from region to region, varying with how the patient uses the dentures. (3) Most often, an opposite large or negative pressure immediately followed the production of positive pressure at the same site beneath the denture. Thus, each movement actually traumatizes the tissue twice. (4) Nonmasticatory pressures produced under dentures are as great as or greater than masticatory pressures. (5) Wave forms for each biting maneuver or sound produced can be charted and are typical for each patient, probably representing denture movement. (6) Swallowing unassociated with eating or drinking produced very high positive and very low negative pressures, giving the greatest ranges of pressures recorded in this experiment. (7) Smoking (recorded in only one patient) also produced a great range of pressures. (8) Sticky foods such as cheddar cheese produced greater negative pressures than the other foods tested. (9) The one patient with natural teeth opposing his denture gave much more uniform and lower pressures than did the patients with complete dentures. (10) This method allows visualization of pressure movement under dentures. The effect of these continually occurring, nonmasticatory, induced pressure changes and pressure waves beneath the dentures may well be of greater significance than that of mastication.
A method for using the functionally generated-path technique to fabricate full occlusal porcelain-fused-to-metal fixed partial dentures and crowns has been described. Proper use of this technique in carefully selected patients should eliminate occlusal adjustments and the concomitant polishing and glazing that are often necessary before the restoration can be permanently cemented.
Three edentulous patients were evaluated using the kinesiograph and a specially designed computer program to identify the length of eccentric contacts between their dentures when masticating test foods. Three different interchangeable occlusal arrangements were constructed and tested. Results of the evaluation of more than 1,400 chewing cycles showed that while 25% of masticatory contacts were eccentric, the great majority of contacts were within a distance of 1 mm from centric occlusion. More eccentric contacts occurred in the opening phase than might be expected. Posterior tooth form did not appear to affect the range of eccentric contacts.