Marginal adaptation of provisional crowns made of acrylic and bisacrylic resins using different impression materials

Abstract

Aim: To evaluate the marginal adaptation of provisional crowns made of acrylic and bisacrylic resins using different impression materials. Methods: a metal die and a matrix applied through a direct technique were used to fabricate the specimens. The impression materials used as a matrix were divided into four groups: Irreversible hydrocolloid (IH), laboratory silicone (LS), condensation silicone (CS), and addition silicone (AS). After the impression procedures, each matrix was loaded with the provisional prosthetic materials, Alike, Duralay, Protemp 4, and Structur 3 (n = 12). Marginal discrepancy was evaluated using a stereomicroscope at ×45 magnification. The images obtained were transferred to the Corel Draw X7 program, and the distances from the cervical margins of the specimen to the reference lines at the metal die were measured vertically. The data were analyzed by using 2-way ANOVA followed by the Tukey test (α=.05). Results: the acrylic resins had higher values ​​of marginal discrepancy compared to the bisacrylic resins. A statistically significant difference was found between all impression materials, and the irreversible hydrocolloid presented higher values of discrepancy (303.28–613.31 μm), whereas addition silicone had the lowest (48.61–190.06 μm). Conclusions: the bisacrylic resins had a better marginal adaptation compared to the acrylic resins. The addition silicone promoted a better marginal adaptation of the provisional prosthetic materials tested, followed by condensation silicone, laboratory silicone, and irreversible hydrocolloid.

Analysis of the marginal adaptation of different crowns fabricated with computer-aided technology using an intraoral digital scanner

“…The crowns were adapted to the prepared dental unit (mandibular right second molar) with the aid of a "C" clamp and maintained in a standardized position during the analysis in a stereomicroscope lupe 31 (Optima MDCE-5ª 2.0, Hiperquímica, Santo André, Brazil) (figure 1). Photographs were obtained at 45X magnification from the buccal, lingual, mesial, and distal surfaces, and images were transferred to the CorelDraw X7 program.…”