Tabriz University of Medical Sciences Journal of Dental Research, Dental Clinics, Dental Prospects 2008-210X 7 1 2013 03 01 Subcutaneous Connective Tissue Reactions to Various Endodontic Biomaterials: An Animal Study 15 21 10.5681/joddd.2013.003 EN Mohammad Ali Saghiri Nader Tanideh Franklin Garcia-Godoy Mehrdad Lotfi Kasra Karamifar Dariush Amanat Journal Article 10.5681/joddd.2013.003 2012 07 16 Background and aims. Biocompatibility of root-end filling materials is a matter of debate. The aim of this study was to compare the biocompatibility of a variety of commercial ProRoot WMTA cements and a resin-based cement (Geristore®) with different pH values of setting reaction and different aluminum contents, implanted into the subcutaneous connective tissue of rats at various time intervals. Materials and methods. Fifty Sprague-Dawley rats were used in this study. Polyethylene tubes were filled with Angelus WMTA, ProRoot WMTA, Bioaggregate, and Geristore. Empty control tubes were implanted into subcutaneous tissues and harvested at 7-, 14-, 28- and 60-day intervals. Tissue sections of 5 μm were stained with hematoxylin and eosin and observed under a light microscope. Inflammatory reactions were categorized as 0, none (without inflammatory cells); 1, mild (inflammatory cells ≤25); 2, moderate (25-125 inflammatory cells); and 3, severe (>125 inflammatory cells). Statistical analysis was performed with Kruskal-Wallis and Mann Whitney U tests. Results. ProRoot WMTA and Angelus elicited significantly less inflammation than other materials (P<0.05). After 7 days, however, all the materials induced significantly more inflammation than the controls (P<0.05). Angelus-MTA group exhibited no significant differences from the Bioaggregate group (P=0.15); however, ProRoot WMTA elicited significantly less inflammation than Bioaggregate (P=0.02). Geristore induced significantly more inflammation than other groups (P<0.05). Conclusion. Geristore induced an inflammatory response higher than ProRoot WMTA; therefore, it is not recommended for clinical use.