Biomedical subjects

R G Palma

Publications and source records attributed to R G Palma.

2 recordsLinked to original sources

PubMed1998

Bond strength to dentin with artificial carious lesions: influence of caries detecting dye.

PURPOSE: To evaluate the influence of dyes for caries detection on tensile bond strength of adhesive materials to artificial carious dentin. MATERIALS AND METHODS: Buccal and lingual enamel of human molars were removed leaving intact dentin surfaces. The entire surface of each specimen was covered with nail varnish, keeping a window area of 4 x 4 mm. Artificial carious lesions were induced with acidified gel. Three dyes (0.5% basic fuchsin; Caries Finder and Cari-D-Tect) were used according to manufacturers' recommendations. Specimens were etched with 35% phosphoric acid for 20 s, washed and dried, leaving a wet dentin surface. The adhesive system (Prime & Bond 2.0) was applied in two layers and light-cured. Restorative materials (TPH Spectrum, Dyract, Advance) were bonded using a 3-mm diameter inverted-cone mold. Control groups were made without dye. Eight samples were tested for each group. After 24 hrs of storage in distilled water, the samples were debonded using a testing machine at 0.5 mm/min crosshead speed. RESULTS: ANOVA and Tukey-Kramer test showed that TPH Spectrum (0.73 MPa) and Dyract (0.74 MPa) had similar bond strengths, and both were higher than Advance (0.0 MPa), which was statistically different (P < 0.01). The use of the dyes did not cause any changes in tensile bond strength for any tested materials.

Analysis of Variance↗

PubMed1997

Effects of acid etching on dentin surface: SEM morphological study.

The aim of this in vitro study was to evaluate, using scanning electron microscopy (SEM), the effects of acid solutions on dentin surface, and to analyze the depth of demineralization that the acid solutions cause on dentin, using different acids. Fifteen 3-mm thick dentin discs were prepared from the middle third of human molars. Standard smear layer was prepared on the dentin surface using 600 grit sandpaper, for 1 minute. The acids used were 10%, 35% and 37.5% phosphoric acid and 10% maleic acid, for 15 seconds, washed and dried. The control group received no treatment. Dentin discs were fractured, observed on the horizontal surface and also on the fractured surface to evaluate the depth of demineralization. Specimens were immersed in 4% glutaraldehyde in phosphonate buffer, and prepared for SEM examination at 2000X and 4000X magnification. Acid etching of dentin, regardless of the concentration of phosphoric acid, caused removal of the smear layer, exposing the apertures of dentinal tubules. This was not observed when 10% maleic acid was used. At the fractured surface, one could observe an increase in demineralization of the width of dentinal tubules, to a specific depth of about 8.19 to 11 mm, except for 10% maleic acid.

Acid Etching, Dental↗