Sicknan Soares da Rocha^I; Fabiane Nogueira^II; Anelise Rodolfo Ferreira Pieralini^II; Ricardo Faria Ribeiro^III; Gelson Luis Adabo^IV

^IProfessor of Dental Clinic, Department of Prevention and Oral Rehabilitation, Federal University of Goiás, Goiânia, GO, Brazil 
^IIGraduate student - Department of Dental Materials and Prosthodontics, Faculdade de Odontologia de Araraquara, Unesp - Univ Estadual Paulista, Araraquara, SP, Brazil 
^IIIProfessor of Prosthodontics, Department of Dental Materials and Prosthodontics, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil 
^IVProfessor of Dental Materials - Department of Dental Materials and Prosthodontics, Faculdade de Odontologia de Araraquara, Unesp - Univ Estadual Paulista, Araraquara, SP, Brazil

ABSTRACT

This study analyzed the reaction layer and measured the marginal crown fit of cast titanium applied to different phosphate-bonded investments, prepared under the following conditions (liquid concentration/casting temperature): Rema Exakt (RE) - 100%/237°C, 75%/287°C, Castorit Super C (CS)-100%/70°C, 75%/141°C and Rematitan Plus (RP)- 100%/430°C (special to titanium cast, as the control group). The reaction layer was studied using the Vickers hardness test, and analyzed by two way ANOVA and Tukey's HSD tests (α = 0.05). Digital photographs were taken of the crowns seated on the die, the misfit was measured using an image analysis system and One-way ANOVA, and Tukey's test was applied (α = 0.05). The hardness decreased from the surface (601.17 VHN) to 150 μm (204.03 VHN). The group CS 75%/141°C presented higher hardness than the other groups, revealing higher surface contamination, but there were no differences among the groups at measurements deeper than 150 μm. The castings made with CS - 100%/70°C presented the lowest levels of marginal misfit, followed by RE -100%/237°C. The conventional investments CS (100%) and RE (100%) showed better marginal fit than RP, but the CS (75%) had higher surface contamination.

Descriptors: Dental casting investment; Dental alloys; Titanium; Dental casting technique; Dental prosthesis.