Linear dimensional changes in plaster die models using different elastomeric materials

• Published in: Brazilian oral research Vol. 24; no. 3; pp. 336 - 341
• Main Authors: Pereira, Jefferson Ricardo, Murata, Karina Yumi, Valle, Accácio Lins do, Ghizoni, Janaina Salomon, Shiratori, Fábio Kenji
• Format: Journal Article
• Language: English
• Published: Brazil Sociedade Brasileira de Pesquisa Odontológica - SBPqO 01.09.2010; Sociedade Brasileira de Pesquisa Odontológica
• Subjects: Analysis of Variance; Calcium Sulfate - chemistry; Dental Abutments; Dental impression materials; Dental Impression Materials - chemistry; Dental impression technique; Dental Impression Technique - instrumentation; Dental Models; Dental prosthesis; Dentistry; DENTISTRY, ORAL SURGERY & MEDICINE; Equipment Design; Materials Testing; Polymers - chemistry; Silicone Elastomers - chemistry; Surface Properties; Dental prosthesis; Dental impression technique; Dental impression materials
• ISSN: 1806-8324; 1807-3107; 1807-3107; 1806-8324
• DOI: 10.1590/S1806-83242010000300013

Dental impression is an important step in the preparation of prostheses since it provides the reproduction of anatomic and surface details of teeth and adjacent structures. The objective of this study was to evaluate the linear dimensional alterations in gypsum dies obtained with different elastomeric materials, using a resin coping impression technique with individual shells. A master cast made of stainless steel with fixed prosthesis characteristics with two prepared abutment teeth was used to obtain the impressions. References points (A, B, C, D, E and F) were recorded on the occlusal and buccal surfaces of abutments to register the distances. The impressions were obtained using the following materials: polyether, mercaptan-polysulfide, addition silicone, and condensation silicone. The transfer impressions were made with custom trays and an irreversible hydrocolloid material and were poured with type IV gypsum. The distances between identified points in gypsum dies were measured using an optical microscope and the results were statistically analyzed by ANOVA (p < 0.05) and Tukey's test. The mean of the distances were registered as follows: addition silicone (AB = 13.6 µm, CD=15.0 µm, EF = 14.6 µm, GH=15.2 µm), mercaptan-polysulfide (AB = 36.0 µm, CD = 36.0 µm, EF = 39.6 µm, GH = 40.6 µm), polyether (AB = 35.2 µm, CD = 35.6 µm, EF = 39.4 µm, GH = 41.4 µm) and condensation silicone (AB = 69.2 µm, CD = 71.0 µm, EF = 80.6 µm, GH = 81.2 µm). All of the measurements found in gypsum dies were compared to those of a master cast. The results demonstrated that the addition silicone provides the best stability of the compounds tested, followed by polyether, polysulfide and condensation silicone. No statistical differences were obtained between polyether and mercaptan-polysulfide materials.