| 1265 Effect of Fillers and Finishing Technique on the Contact Angles of Dental Resin | ||
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C. SHEN, E.M. SONG, and V.V. GORDAN, University of Florida, Gainesville, USA Objectives: This study investigated the influence of fillers and finishing technique on the contact angle of a dental resin. Methods: Eighteen plates each (12x20x1mm) were made from a composite (F) and its corresponding unfilled (U) resin (Filtek® Z250; 3M/ESPE). HPLC water, formamide and a-bromonaphthalene, in the decreasing order of surface tension and hydrophilicity, were used as probing media. Six specimens from each material were used for each of the following surface conditions: finishing as-prepared with Mylar® strip (MS), finishing with 15mm diamond polishing plate (DP), and finishing with 1mm Al2O3 slurry (AS). A dynamic contact angle analyzer (DCA312, Cahn Instrument) was used to measure the advancing (qA) and the receding (qR) contact angles. Between changes of probing medium, the specimen was sonicated in ethanol/water bath, rinsed with distilled water, and dried with air. Results: The values of contact angles by probing media are significantly different (p<0.0001) and in the order of a-bromonaphthalene (qA:14.0°~36.7°; qR:20.1°~34.7°) > formamide (qA: 52.1°~72.4°; qR:26.0°~39.3°) > water (qA:70.7°~89.0°; qR: 45.5°~51.1°). ANOVA of the influence of variables on the values of qA shows that F>U and AS>DP,MS with a-bromonaphthalene, U>F and AS>MS,DP with formamide, no difference between materials (p=0.5765) and surface conditions (p=0.5602) with water, no difference between materials (p=0.8408) with Mylar finishing specimens, U>F with diamond finishing , F>U with Al2O3 finishing. ANOVA of the influence of variables on the values of qR shows that F>U and AS>DP>MS with a-bromonaphthalene, U>F and AS,MS>DP with formamide and water, U>F with Mylar finishing, and no difference between materials with either diamond or Al2O3. Conclusions: Contact angle values depend on the surface properties of the probing medium. The presence of fillers makes the resin surface more hydrophilic as the filled resins exhibited lower contact angles than those of unfilled resins with water and formamide. Contact angle varies with the finishing technique. | ||
| Seq #124 - Surface Roughness and Color of Restorative Materials 3:45 PM-5:00 PM, Thursday, 7 March 2002 San Diego Convention Center Exhibit Hall C | ||
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