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Biomedical subjects

F M McIntyre

Publications and source records attributed to F M McIntyre.

6 recordsLinked to original sources
PubMed1993

Marginal gap width of a new refractory porcelain system.

This study was conducted to determine whether matching the physical properties of refractory die material to porcelain could increase the marginal accuracy of porcelain inlays. Restorations made with a matched Fortune refractory porcelain system were compared with restorations made with unmatched Vita porcelain and Polyvest refractory material. Thirty addition-silicone impressions were made of a master mesioocclusodistal inlay preparation. Fifteen refractory dies were made for each of the refractory materials. The dies were prepared and the porcelain applied according to the manufacturer's specifications. Three measurements of marginal gap were recorded adjacent to premarked points on each proximal box by use of a Unitron microscope with micrometer adjustment. The mean marginal gap was 51.24 +/- 20.84 microns for the matched material and 100.43 +/- 17.30 microns for the unmatched material. A Student's t-test was performed, which showed a significantly greater mean gap for the unmatched system compared with the matched system (t[28] = 7.03, p < 0.005). The results indicate that a matched refractory porcelain system can produce restorations with significantly improved marginal accuracy.

Dental Alloys↗
PubMedDate not supplied

The effect of film thickness on the bond strength of polycarboxylate cement.

This study examined the bond strength of polycarboxylate cement when used to cement gold alloy specimens to dentin. The film thickness was controlled and varied over a range of 10 to 150 microns. Tensile and shear bond strengths were measured and, contrary to anticipated results, there was an increase in bond strength as the film thickness increased. In this study, the bond strength of polycarboxylate cement as it relates to film thickness is evaluated in relationship to the clinically significant value of 50 microns over the thickness range of 150 microns.

Cementation↗