Oclusion

Braz 140 Dent J (2005) 16(2): 140-144

V.O. Pagnano et al.

ISSN 0103-6440

Clinical Evaluation of Interocclusal Recording Materials in Bilateral Free End Cases
Valéria de Oliveira PAGNANO1 Osvaldo Luiz BEZZON1 Maria da Glória Chiarello de MATTOS1 Ricardo Faria RIBEIRO1 Miriam Lacalle TURBINO2

1Department of Dental Materials and Prosthodontics, Faculty of Dentistry of Ribeirão Preto,University of São Paulo, Ribeirão Preto, SP, Brazil
2Department of Restorative Dentistry, Faculty of Dentistry, University of São Paulo (FOUSP), São Paulo, SP, Brazil

Five combinations of materials commonly used for intermaxillary records in cases of bilateral free end saddle were evaluated: acrylic resin base + wax; acrylic resin base + wax + ZOE paste; acrylic resin base + wax + Duralayresin; condensation silicone; and acrylic resin plate + irreversible hydrocolloid. The materials were evaluated by measuring the vertical distance between pairs of reference points located on the bases of the upper and lower articulated casts. The measurements obtained by manual articulation of the casts were used as the standards to which the measurements obtained with the recording materials werecompared. ANOVA revealed significant differences among the materials and the Tukey’s test showed that condensation silicone differed significantly (p0.05) were observed among the remaining materials. The condensation silicone presented the greatest differences from the measurements obtained by manual articulation of the casts whereas the acrylic resin base + wax combination presented the leastdifferences. Based on the findings of this study, the following scale of fidelity can be settled from best to worst: acrylic resin base + wax; acrylic resin plate + alginate; acrylic resin base + wax + ZOE; acrylic resin base + wax + Duralay; and condensation silicone. Key Words: interocclusal recording materials, free end cases.

INTRODUCTION
Oral rehabilitation involves a sequence of steps thatmust be followed in a highly judicious manner. The success of any prosthetic rehabilitating treatment depends on several aspects related to the precise mounting of casts in the articulator. When maximum intercuspation is considered, in cases in which the number of teeth present is satisfactory and will provide cast stability, the casts can be mounted by manual articulation (1-6). On the other hand,when large edentulous spaces are present, specifically in posterior free end cases, cast mounting is considerably more complex (7). There is a higher risk of distortion due to interference by the soft tissues of the margins,

which can be compressed and may give origin to errors on cast mounting, if special attention is not taken during impression. Furthermore, the lack of teeth that articulatewith their antagonists poses an additional difficulty to recording and increases the need for accurate transfer of the interocclusal relationship and vertical dimension (8). These parameters are usually fulfilled by using registration bases fitted into wide edentulous spaces or free ends. The recording base should provide adequate fitting as well as rigidity and stability. The purpose of thisstudy was to evaluate 5 combinations of materials used in daily clinical practice to obtain intermaxillary records for bilateral free end cases.

Correspondence: Profa. Dra. Valéria Oliveira Pagnano de Souza, Departamento de Materiais Dentários e Prótese, Faculdade de Odontologia de Ribeirão Preto, USP, Av. do Café S/N, Monte Alegre 14040-904 Ribeirão Preto, SP, Brasil. Tel: +55-16-3602-4005. Fax:+55-16-36330999. E-mail: valpag@forp.usp.br

Braz Dent J 16(2) 2005

Interocclusal recording materials

141

MATERIAL AND METHODS
Five patients with complete upper dentition and bilateral lower edentulousness were enrolled as volunteers for this study. As an inclusion criterion, only individuals who had some teeth remaining in the mandibular arch (up to premolars) were selected, in...