Mineral Trioxide Aggregate–based Sealer: Analysis of Tissue Reactions to a New Endodontic Material Roberta Kochenborger Scarparo, MSc, Daniel Haddad, DDS, Gerson Arison Xavier Acasigua, Anna Cristina Medeiros Fossati, PhD, Elaine Vianna Freitas Fachin, PhD, and Fabiana Soares Grecca, PhD Abstract Introduction: The aim of this study was to evaluate the subcutaneous connective tissue reaction to mineral trioxide aggregate (MTA)-based sealer (Endo CPM Sealer; CPM Sealer; EGEO SRL, Buenos Aires, Argentina), MTA, and an epoxy resin-based sealer (AH Plus; Dentsply HERO Indu ´ stria e Come ´ rcio Ltda, Petro ´ p- olis, RJ, Brazil). Methods: Polyethylene tubes contain- ing the test materials and empty tubes (control group) were implanted in the subcutaneous tissue of 18 rats. After 7, 30, and 60 days, observations were made for cellular inflammatory components, fibrous condensa- tion, and abscess formation. Comparisons between groups and periods of time were made using the Fried- man test and the Kruskall-Wallis test. Results: Lympho- cytes and plasmacytes were more intensely observed in the reaction to AH Plus sealer after 30 days (p < 0.05). MTA and the Endo CPM Sealer presented a behavior similar to that of the control group throughout the whole experiment. Conclusion: The Endo CPM Sealer pre- sented biological potential. Characteristics of the inflam- matory reaction were equivalent to those produced by MTA. (J Endod 2010;36:1174–1178) Key Words Biocompatibility, connective tissue, endodontics, mineral trioxide aggregate M ineral trioxide aggregate (MTA) was developed to seal communications between a tooth and its external surfaces (1, 2). Currently, it is being used not only in root perforations but also in conservative pulpal treatments (3, 4), in obturation of the apical portion of immature teeth (5, 6), and in retrograde obturations (7, 8); it is widely accepted for its biocompatibility (9–11) and excellent sealing capacity (1). The use of MTA for root canal filling should be explored because there is not so far an endodontic sealer that offers ideal biocompatibility characteristics (12). On the other hand, MTA physical characteristics make both manipulation and the filling process of the root canal system difficult. In order to capitalize on the biological and sealing characteristics of MTA and, at the same time, improve its flow rate and manipulation characteristics, a new formula- tion of MTA-labeled Endo-CPM Sealer (CPM Sealer; EGEO SRL, Buenos Aires, Argentina) was created. The powder consists of fine hydrophilic particles that form a colloidal gel in presence of moisture. It becomes solid and forms a hard sealer in 1 hour. The main components are tricalcium silicate, tricalcium oxide, tricalcium aluminate, and other oxides. The liquid consists of saline solution and calcium chloride (13). Presented as a white modified Portland cement–based material, its most signifi- cant difference is the presence of a large amount of calcium carbonate, which intends to increase the release of calcium ions and offers good sealing properties, adhesion to the dentinal canal walls, adequate flow rate, and biocompatibility (14–16). According to Vasconcelos et al (17), Endo CPM Sealer has an alkaline pH and an ability to release calcium ions. When analyzing the Endo CPM Sealer regarding its sealing ability on apical plugs, it was observed that there is no difference between gray MTA Angelus (Angelus Soluc ¸o ˜ es Odontolo ´ gicas, Londrina, PR, Brazil) and Endo CPM Sealer (13). However, few studies have tackled the analysis of this material’s biocompatibility (15, 18, 19), comparing it with MTA and other sealers that have been already used in endodontics. The aim of this study was to evaluate the subcutaneous connective tissue reaction to MTA-based sealer (Endo CPM Sealer), MTA, and an epoxy resin-based sealer (AH Plus; Dentsply HERO Indu ´ stria e Come ´ rcio Ltda, Petro ´ polis, RJ, Brazil). Materials and Methods The present study was approved by the Research and Ethics Committee of the School of Dentistry of the Federal University of Rio Grande do Sul, Brazil (n. 13534). A total of 18 animals (Rattus norvegicus albinus Wistar) were used. They were divided into three experimental periods (7, 30, and 60 days). The inflammatory reactions were evaluated in four study groups: group 1, Endo CPM Sealer; group 2, Gray MTA; group 3, epoxy resin-based sealer; and group 4, control group (empty tube). The animals were anesthetized with 0.008 mL/100 g of ketamine and 0.004 mL/ 100 g of xylazine hydrochloride 2% (Virbac do Brasil Indu ´ stria e Come ´ rcio Ltda, Sa ˜o Paulo, SP, Brazil). A dorsal trichotomy was manually performed, and the area was dis- infected with alcohol-iodine solution. Four 0.5-cm-long incisions were made in the animal’s back, 2 cm from the spine and at least 2 cm apart from one another. Using blunt-tipped scissors, the lateral tearing of the subcutaneous tissue provided four surgical cavities displayed in quadrants equidistant from the center of the animal’s back. Polyethylene tubes, approximately 10 mm long and 1.5 mm in diameter (Abott From the School of Dentistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. Address requests for reprints to Dr Roberta K. Scarparo, Avenida Ramiro Barcelos, 2492 CEP 90035-003, Porto Alegre, RS, Brazil. E-mail address: robks@terra.com.br. 0099-2399/$0 - see front matter Copyright ª 2010 American Association of Endodontists. doi:10.1016/j.joen.2010.02.031 Basic Research—Technology 1174 Scarparo et al. JOE — Volume 36, Number 7, July 2010