Indiana University-Purdue University Indianapolis (IUPUI) / The purpose of this laboratory study was to determine
whether etching of flat bovine enamel surfaces with a 50
per cent aqueous solution of phosphoric acid for 60 seconds
increases the bonding of a conventional restorative acrylic
resin and a new polycarboxylate cement. The test specimens
were subjected to 24 hours, 30 days and six months storage
in water and then subjected• to temperature stress cycling
and intermittent tensile stress cycling. A tensile test
was used to measure the bond strength of both materials.
The results of the Newman-Keul's test showed that
pretreating the enamel surface with 50 per cent phosphoric
acid significantly increased the bonding of the restorative
resin, and that the cavity sealer supplied by the manufacturer
further improved the resin attachment to enamel
surfaces previously etched with phosphoric acid. The
bonding of the resin to acid-etched enamel surfaces pretreated
with or without the cavity sealer was unaffected by
prolonged storage in water, temperature stress cycling, and
intermittent tensile stress cycling. However, a significant
reduction in the adhesion of the acrylic resin to polished-enamel
surfaces pretreated with or without the cavity sealer
was observed when the test specimens were subjected to the
same testing conditions.
The data obtained for the polycarboxylate cement test
specimens showed that etching of the enamel surface with
phosphoric acid also provided slightly higher adhesive
values than the control specimens.
Results obtained revealed that prolonged storage in
water, and temperature and mechanical stress cycling did not
affect the adhesion of the polycarboxylate cement to acid-etched
enamel surfaces. However, thermal and mechanical
stress cycling after prolonged storage in water appeared
to decrease the adhesion of the cement to polished enamel
surfaces.
When Ca45 was used to assess the marginal seal of resin
restorations placed into acid-etched Class V cavity preparations
in extracted human teeth, the autoradiographs showed that
etching of the cavity preparations with 50 per cent phosphoric
acid improved the marginal seal of the restorative resin
after one-week storage in water. When both the acid-etched
and control restorations were thermal stress cycled 2500
times at a 40°C temperature differential, a slight improvement
in the marginal seal of the acid-etched restorations
was observed.
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/4181 |
| Date | January 1970 |
| Creators | Lee, Brian Dalvin, 1942- |
| Contributors | Gilmore, H. William (Homer William), Mercer, Victor H., 1928-, Garner, La Forrest Dean, 1933- |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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