Search PubMed⌕ Search

Biomedical subjects

H A Williams

Publications and source records attributed to H A Williams.

At least 37 records · Page 2Linked to original sources
PubMed1978

Surface characteristics of resin-coated composite restorations.

Twenty-four maxillary anterior composite restorations from a clinical study of resin coating were examined at the time of baseline evaluation and at 23 months; electroplated positive replicas, impression negative replicas, and SEMs were used for evaluation. Coated restorations had smooth surfaces after 23 months, in comparison with rough surfaces of uncoated restorations. Defects in some of the resin coatings were found at the time of baseline evaluation; these included isolated areas of the composite or etched enamel that were not covered by the resin. Later examinations showed cracking of part of the edges of resin coating, development of bare areas, thinning of the coating edges, or generalized loss of the protective coating. The defects seen immediately after placement of the coatings were probably caused by errors in technique that include: application of the resin in a layer that was too thin; surface contaminants in the area of application; moisture on the surface of the composite or enamel; and areas of inadequate enamel etching were adjacent to the cavosurface margin of the composite. The appearance of bare spots or total loss or thinning of the resin coating edges during the later examinations is caused by wearing or abrading of the resin coatings from natural or mechanical causes. This seems to be a function of the initial coating thickness and its location on the tooth.

Acid Etching, Dental↗
PubMed1977

A comparison of glazing materials for composite restorations.

Composite restorations containing quartz fillers have shown persistent roughness after finishing which contributes to marginal discoloration and staining. Resin finish coatings have been used to attempt to overcome this problem. This study was designed to compare the durability of two resin coating materials used on two brands of composite restorative materials. Results showed that composites glazed with resin coating finishes at placement maintained their luster, color match, and surface smoothness significantly better after one year than composites that were not coated. After a year it was concluded that composites on which the resin coating is intact maintain their color match, luster, and smoothness significantly better than uncoated composite restorations.

Acid Etching, Dental↗