Effect of anti-rotation devices on biomechanical behaviour of teeth restored with cast post-and- cores L. H. A. Raposo 1 , G. R. Silva 1 , P. C. F. Santos-Filho 1 , P. V. Soares 1 , P. B. F. Soares 1 , P. C. Simamoto-Junior 2 , A. J. Fernandes-Neto 3 & C. J. Soares 1 1 Department of Operative Dentistry and Dental Materials, Biomechanics Group, Federal University of Uberla ˆndia, Minas Gerais, Brazil; 2 Healthy Technical School, Federal University of Uberla ˆ ndia, Minas Gerais, Brazil; and 3 Department of Fixed Prosthodontics and Dental Materials, Biomechanics Group, School of Dentistry, Federal University of Uberla ˆndia, Minas Gerais, Brazil Abstract Raposo LHA, Silva GR, Santos-Filho PCF, Soares PV, Soares PBF, Simamoto-Junior PC, Fernandes-Neto AJ, Soares CJ. Effect of anti-rotation devices on biomechanical behaviour of teeth restored with cast post-and-cores. Interna- tional Endodontic Journal, 43, 681–691, 2010. Aim To test the hypothesis that the presence of an anti-rotation device (ARD) and its location can influ- ence the biomechanical behaviour of root filled teeth restored with cast post-and-cores and metallic crowns. Methodology Fifth two bovine incisor roots were selected and divided into four groups (n = 13): Nd- without ARD; Bd- buccal ARD; Ld- lingual ARD; BLd- buccal and lingual ARD. The specimens were restored with cast post-and-cores and metallic crowns. After a fatigue process (3 · 10 5 50 N), three strain gauges were attached on the buccal, lingual and proximal surfaces and the samples of each group (n = 3) were submitted to a 0–100 N load. Fracture resistance was assessed in a mechanical testing machine (n = 10). Strain values and fracture resistance data were anal- ysed by one-way anova and Tukey Honestly Signifi- cant Difference (HSD) test (a = 0.05). The failure mode was then evaluated under an optical stereomicroscope. Bidimensional models of each group were generated for finite element analysis (FEA) and analysed using the von Mises criteria. Results No significant difference in fracture resis- tance values and fracture modes occurred between the four groups. The BLd group had higher stress concen- trations in the buccal dentine and higher strain values on the proximal surfaces. Conclusions The anti-rotation devices did not influ- ence significantly the fracture resistance and fracture mode. However, the stress–strain values were increased when the anti-rotation device was prepared on the buccal and lingual faces concomitantly. Keywords: anti-rotation device, cast post-and-core, finite element analysis, fracture mode, fracture resis- tance, strain gauge test. Received 20 October 2009; accepted 2 April 2010 Introduction With the development of endodontic therapy, recovery and maintenance of severely damaged teeth became possible. However, there can be a major challenge in restoring these teeth. Structural loss means that post- and-cores are often required to maintain the restora- tion in place (Papa et al. 1993, Morgano & Brackett 1999, Joshi et al. 2001). Root canal preparation results in dentine removal and increases the risk of fracture when compared to intact teeth, because the resistance of root filled teeth is directly related to the amount and quality of the remaining tooth tissue (Reeh et al. 1989, Morgano & Brackett 1999, Heydecke et al. 2001). More- over, the posts do not increase the tooth-restoration Correspondence: Carlos Jose ´ Soares, Faculdade de Odontologia – Universidade Federal de Uberla ˆndia, A ´ rea de Dentı ´stica e Materiais Odontolo ´gicos, Av. Para ´, no 1720, Campus Umu- arama, Bloco 2B, Sala 2B-24, CEP: 38405-902, Uberla ˆndia, Minas Gerais, Brazil (Tel.: +55 34 32182255; fax: +55 34 32182279; e-mail: carlosjsoares@umuarama.ufu.br). doi:10.1111/j.1365-2591.2010.01739.x ª 2010 International Endodontic Journal International Endodontic Journal, 43, 681–691, 2010 681