Effect of Ceramic Surface Treatment on Dynamic Contact Angle

Objective: This study tested the hypothesis that chemical etching and silane coating of a ceramic surface would reduce the apparent dynamic contact angle (DCA). Methods: Ten hot-pressed leucite-based flat ceramic plates (Empress)^# were fabricated and polished to 1200-grit for each of the following procedures: (1) as-polished control; (2) Ultradent silane (UD)^† coated; (3) 3M silane (3S)^‡ coated; (4) etched with 9.5% hydrofluoric acid (HF)^† for 1 min; (5) 1-min etching with HF followed by UD coating; (6) 1-min etching with HF followed by 3S coating. Wetting of the surfaces was studied using a DCA analyzer (Cahn Thermo, Madison, WI). Advancing and receding contact angles (q_a and q_r) values were obtained using a resin (R; 65% Bis-GMA, 35% TEGDMA; g=39.7mJ/m²) and HPLC grade water (W;g=72.6mJ/m²) as probing liquids. Results: The mean±SD angles (degree) are: (1W) q_a=66.7±3.3, q_r=36.4±5.7; (1R) q_a=50.4±2.3, q_r=40.8±1.4; (2W) q_a=80.0±0.7, q_r=68.7±2.0; (2R) q_a=33.8±5.1, q_r=20.2±3.6; (3W) q_a=47.2±6.5, q_r=46.7±1.2; (3R) q_a=29.1±4.1, q_r=3.7±7.5; (4W) q_a=49.1±9.7, q_r=53.7±8.2; (4R) q_a=47.2±3.9, q_r=0; (5W) q_a=73.4±3.8, q_r=61.5±1.6; (5R) q_a=51.0±2.9, q_r=40.1±2.5; (6W) q_a=54.9±2.4, q_r=58.1±2.4; (6R) q_a=22.0±9.5, q_r=0. T-test showed that DCA by resin are lower than those by water (p<0.0001), except for the q_r of the control (p=0.0835). Two-way ANOVA revealed that there were interactions between silane used and surface treatment (etch and polish) for q_a and q_r. One-way ANOVA showed that UD yielded higher q_a and q_r values than those by 3S (p<0.0001). As-polished control specimens exhibited higher q_a and q_r values than those by 3S, except that on etched surface probed by water (p<0.0001). Conclusions: Application of UD resulted in more hydrophobic surfaces and reduced surface wettability by resin. Etching, 3S coating, or combination of the two increased the wettability ceramic surfaces by either water or resin. ^#Ivoclar AG, Liechtenstein;^†Ultradent Products Inc., USA; ^‡3M Dental Products, USA. Supported by Capes Brasil.

*1653 Effect of Ceramic Surface Treatment on Dynamic Contact Angle*
A. DELLA BONA, University of Passo Fundo, Brazil, and C. SHEN, University of Florida, Gainesville, USA Objective: This study tested the hypothesis that chemical etching and silane coating of a ceramic surface would reduce the apparent dynamic contact angle (DCA). Methods: Ten hot-pressed leucite-based flat ceramic plates (Empress)^# were fabricated and polished to 1200-grit for each of the following procedures: (1) as-polished control; (2) Ultradent silane (UD)^† coated; (3) 3M silane (3S)^‡ coated; (4) etched with 9.5% hydrofluoric acid (HF)^† for 1 min; (5) 1-min etching with HF followed by UD coating; (6) 1-min etching with HF followed by 3S coating. Wetting of the surfaces was studied using a DCA analyzer (Cahn Thermo, Madison, WI). Advancing and receding contact angles (q_a and q_r) values were obtained using a resin (R; 65% Bis-GMA, 35% TEGDMA; g=39.7mJ/m²) and HPLC grade water (W;g=72.6mJ/m²) as probing liquids. Results: The mean±SD angles (degree) are: (1W) q_a=66.7±3.3, q_r=36.4±5.7; (1R) q_a=50.4±2.3, q_r=40.8±1.4; (2W) q_a=80.0±0.7, q_r=68.7±2.0; (2R) q_a=33.8±5.1, q_r=20.2±3.6; (3W) q_a=47.2±6.5, q_r=46.7±1.2; (3R) q_a=29.1±4.1, q_r=3.7±7.5; (4W) q_a=49.1±9.7, q_r=53.7±8.2; (4R) q_a=47.2±3.9, q_r=0; (5W) q_a=73.4±3.8, q_r=61.5±1.6; (5R) q_a=51.0±2.9, q_r=40.1±2.5; (6W) q_a=54.9±2.4, q_r=58.1±2.4; (6R) q_a=22.0±9.5, q_r=0. T-test showed that DCA by resin are lower than those by water (p<0.0001), except for the q_r of the control (p=0.0835). Two-way ANOVA revealed that there were interactions between silane used and surface treatment (etch and polish) for q_a and q_r. One-way ANOVA showed that UD yielded higher q_a and q_r values than those by 3S (p<0.0001). As-polished control specimens exhibited higher q_a and q_r values than those by 3S, except that on etched surface probed by water (p<0.0001). Conclusions: Application of UD resulted in more hydrophobic surfaces and reduced surface wettability by resin. Etching, 3S coating, or combination of the two increased the wettability ceramic surfaces by either water or resin. ^#Ivoclar AG, Liechtenstein;^†Ultradent Products Inc., USA; ^‡3M Dental Products, USA. Supported by Capes Brasil.
Seq #207 - Ceramics: Surface Treatment, Surface Chemistry, and Bonding 11:00 AM-12:15 PM, Saturday, 15 March 2003 Henry B. Gonzalez Convention Center Exhibit Hall C
Back to the Dental Materials: III - Ceramics and Cements Program Back to the 32nd Annual Meeting and Exhibition of the AADR (March 12-15, 2003)
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