Influence of water/powder ratio in the mineral and synthetic casts

• Published in: Brazilian journal of oral sciences Vol. 13; no. 3; pp. 225 - 228
• Main Authors: Tavarez, Rudys Rodolfo De Jesus, Klug, Rufino José, Vieira, Mayana Soares, Bezerra, Gisele Lima, Bandeca, Matheus Coelho, Firoozmand, Leily Macedo
• Format: Journal Article
• Language: English
• Published: Faculdade de Odontologia de Piracicaba - UNICAMP 01-09-2014
• Subjects: DENTISTRY, ORAL SURGERY & MEDICINE; compressive strength; dental materials; calcium sulfate
• ISSN: 1677-3225; 1677-3225
• DOI: 10.1590/1677-3225v13n3a12

AIM: To evaluate the influence of varying the water/powder ratio on the compressive strength of type IV mineral and synthetic casts. METHODS: Four commercial brands of type IV mineral and synthetic casts were evaluated: Durone, Herostone, Fuji Rock, and Elite Rock. Ninety-six test samples were prepared from a silicone matrix, according to ADA's standard no. 25. The samples were prepared according to the manufacturer's recommendations with a normal water/powder ratio (n = 12) and with 20% extra water (n = 12), forming the control (A) and experimental (B) subgroups, respectively. Compressive strength tests were performed using a universal testing machine EMIC (DL 2000) with a load cell of 2,000 kgf/cm2. The obtained data were analyzed statistically using two-way ANOVA and Tukey's test (α=5%). RESULTS: The synthetic Elite Rock cast was statistically different from the one obtained when the portion of water indicated by the manufacturer was used; no significant differences were found in the remaining casts when the proportion of water was increased by 20%. CONCLUSIONS: the groups of synthetic and mineral casts differed and the water increase (20%) did not cause significant difference on the compressive strength of the materials.