| Autor: |
Martins-Pinto MG; Department of Prosthodontics, School of Dentistry, Lutheran University of Brazil, Canoas, RS., Pisani-Proenca J, Erhardt MC, Spielmann C, Del Castillo-Salmeron R, Lopes LA |
| Jazyk: |
angličtina |
| Zdroj: |
General dentistry [Gen Dent] 2008 Sep-Oct; Vol. 56 (6), pp. 569-73; quiz 574-5, 591-2. |
| Abstrakt: |
This study evaluated how different tooth preparation heights and luting cements affected the retention of metallic full crowns. Tooth preparations were made on 60 extracted maxillary premolars with occluso-cervical heights of 4.0 or 5.0 mm. The nickel chromium (NiCr) metallic crowns in each group were subdivided randomly into three groups (n = 10); the samples in each group were cemented with either a self-adhesive resin cement, a conventional resin cement, or a zinc phosphate cement. Cementation was performed by applying 5.0 kg pressure in 50% relative humidity. Specimens were stored in 100% humidity at 37 degrees C for seven days, at which time they were subjected to a vertical tensile test with a universal testing machine at 0.5 mm/min. Data (Kgf) were analyzed by two-way ANOVA and Tukey's multiple comparisons tests (alpha = 0.01). There was a significant difference in mean force in the height preparations (P < 0.001) and in tensile strength (P < 0.001) among the resin cements. Regardless of the cement used, 5.0 mm high preparations showed significantly higher mean forces than the 4.0 mm high preparations. The self-adhesive resin cement showed significantly higher mean tensile strength than the conventional resin cement; the zinc phosphate cement displayed the lowest retention values. The self-adhesive resin cement displayed retention rates twice that of the zinc phosphate cement. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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