JOURNALOF MATERIALS SCIENCE: MATERIALS IN MEDICINE 15 (2004) 167±173 Evaluation of osteoblast-like cell response to Proroot 2 MTA(mineraltrioxideaggregate)cement G. A. PELLICCIONI 1 * , G. CIAPETTI 2 , E. CENNI 2 , D. GRANCHI 2 , M. NANNI 1 , S. PAGANI 2 , A. GIUNTI 2,3 1 Dipartimento di Scienze Odontostomatologiche, Alma Mater Studiorum/Universita Á di Bologna, via San Vitale 59, 40100 Bologna, Italy 2 Laboratorio di Fisiopatologia degli Impianti Ortopedici, Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy E-mail: ciapetti@ior.it 3 Dipartimento di Scienze Anatomiche, Umane e dell'Apparato Locomotore, Alma Mater Studiorum/Universita Á di Bologna, Italy Some endodontic sealers have been shown to cause local and systemic effects, mainly due to microleakage of chemicals from the sealer. To avoid the risk of toxic effects in vivo, the biological compatibility of ®lling materials has to be assessed. In vitro compatibility of Proroot 2 MTA cement in comparison with two different ®llers used in clinical practice, was examined by testing the adherence, viability, proliferation and secretion of collagen of osteoblast-like cells. In our experimental system, Saos-2 cells challenged with Proroot 2 MTA for 24 and 72h showed a better behaviour than the cells exposed to the other compounds under assay. We found that the cells attached to the rough surface of Proroot 2 MTA cement and spread onto the rough surface. Moreover, the cells on Proroot 2 MTAwere viable, grew, and released some collagen even at 72 h, while cell metabolism and growth was dramatically reduced onto sEBA and amalgam surfaces. A parallel behaviour was found after the cells were challenged with extracts of the different ®llers. In conclusion, according to our in vitro study, Proroot 2 MTA showed a good interaction with bone-forming cells: such behaviour may partially account for its satisfying clinical performance. # 2004 Kluwer Academic Publishers 1. Introduction The placement of a root end ®lling material during periradicular surgery is a procedure of a paramount importance to hermetically seal the endodontic space when this goal has not been achieved by a conventional root canal therapy [1]. Several materials have been developed and tested for this use, but to date, no root end ®lling material is demonstrated to be the ideal one, yet. Recently a material, named Proroot 2 MTA, has been commercialized in the European market and it is quoted to own many of the ideal characteristics [2]. Such cement derives from the original formula of mineral trioxide aggregate (MTA) that was developed at the University of Loma Linda [3, 4]. The MTA cement has been extensively studied and has always showed very good results in all in vitro [5] and in vivo [6,7] tests, either alone or when compared with other root end ®lling materials [8±15]. Particularly regarding the cytotoxicity, MTA was found to be less toxic than (intermediate restorative material) IRM or Super EBA [16±18]. However, the Proroot 2 MTA is a modi®ed version of the original formula, on which most of the studies have been conducted [19]. Such changes have been adopted to improve handling characteristics and colour of this material, i.e. features which are relevant for the clinician [20]. It seems indeed interesting to test the biocompatibility of Proroot 2 MTA to con®rm the good results achieved with the originally patented MTA. The aim of this study was to further investigate the cytotoxicity of Proroot 2 MTA grey as compared with silver amalgam and Super EBA 2 cement using an osteoblastic cell model. Experimental protocol included preparation of the solid specimens, i.e. the cement mixture layered onto the bottom of culture wells, as well as of ``extracts'' from solids, i.e. substances which are eluted from solid into culture medium. Both preparations were tested with osteoblast-like cells. Bone-forming cells have been chosen because of the correlation with in vivo situation, *Author to whom all correspondence should be addressed. 0957±4530 # 2004 Kluwer Academic Publishers 167