d e n t a l m a t e r i a l s 2 9 ( 2 0 1 3 ) 174–180 Available online at www.sciencedirect.com jo ur n al homep age : w ww.intl.elsevierhealth.com/journals/dema Evaluation of marginal and internal fit of ceramic crown copings Juliana Tereza Colpani, Márcia Borba, Álvaro Della Bona ∗ Post-graduate Program in Dentistry, Dental School, University of Passo Fundo, Brazil a r t i c l e i n f o Article history: Received 1 July 2012 Received in revised form 26 October 2012 Accepted 30 October 2012 Keywords: Ceramic CAD–CAM Slip casting Fit Replica technique a b s t r a c t Objectives. (1) To measure the marginal and internal adaptation of different prosthetic crowns infrastructures (IS); (2) to analyze two types of methodologies (replica and weight technique) used to evaluate the adaptation of indirect restorations. Methods. Ceramic IS were fabricated using CAD/CAM technology and slip-casting technique, and metal IS were produced by casting (n = 10). For each experimental group, the adaptation was evaluated with the replica (RT) and the weight technique (WT), using an impression material (low viscosity silicon) to simulate the luting agent. Cross-sectional images of the sil- icon replica were obtained and analyzed with Image J software to measure the low viscosity silicon layer thickness at pre-determined points. The silicon layer was also weighted. Results were statistically analyzed with ANOVA and Tukey’s test (˛ = 0.05). Pearson correlation was used to analyze the relation between the two types of evaluation methods. Results. All IS evaluated showed clinically acceptable internal and marginal adaptation. Metal IS showed the best adaptation, irrespective of the measuring technique (RT and WT). The IS produced by CAD–CAM showed greater gap values at the occlusal area than at other evaluated regions. The IS produced by the dental laboratory technician showed similar gap values at all evaluated regions. There is no correlation between RT and WT (p > 0.05). Significance. Different levels of adaptation were found for the different experimental groups and for the different evaluation methods. However, all IS evaluated showed clinically accept- able values of marginal and internal adaptation. © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. 1. Introduction The internal and marginal adaptation of ceramic restorations is an important factor for the clinical success and longevity of these restorations. The presence of a marginal gap can lead to dissolution of the luting agent, creating an area for biofilm development that may cause caries and periodontal diseases [1–3]. A marginal misfit can be considered acceptable when it is visually imperceptible or cannot be detected using a dental ∗ Corresponding author at: Dental School, University of Passo Fundo, Campus I, BR285, km 171, Passo Fundo, RS, Brazil. Tel.: +55 5433115142. E-mail address: dbona@upf.br (Á. Della Bona). probe. Marginal gap values between 100 and 150 m are con- sidered clinically acceptable [4–11]. In addition, the dimension of the internal gap is also important because internal gaps greater than 70 m can reduce the fracture resistance of dental crowns [12]. Methods to evaluate the adaptation of prosthetic restora- tions have used laser videography [10], profile projector [13], micro-CT and CAD/CAM scanner [14]. The replica technique (RT), or cement analog technique, has been widely used because of its ability to estimate the internal and marginal gap dimension of prosthetic restorations [9]. This technique 0109-5641/$ – see front matter © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.dental.2012.10.012