Evaluation of Rat Alveolar Bone Response to Ange MTA or Experimental Light-cured Mineral Trioxide Using Fluorochromes Jo~ ao Eduardo Gomes-Filho, PhD, Mariana Machado Teixeira de Moraes Costa, PhD, Luciano Tavares Angelo Cintra, PhD, Paulo Carvalho Tobias Duarte, MSc, Aline Satie Takamiya, MSc, Carolina Simonetti Lodi, MSc, and Pedro Fel ıcio Estrada Bernab e, PhD Abstract Introduction: The aim of this study was to evaluate the rat alveolar bone response after the implantation of exper- imental light-cured mineral trioxide aggregate (MTA) or Angelus MTA (Angelus, Londrina, Paran a, Brazil) by histo- logical and fluorescence analysis. Methods: Thirty Wistar Albino rats were divided into three groups. In the control group, empty polyethylene tubes were inserted into the rat alveolar sockets immediately after extraction. In the othergroups, the tubeswere filled with light-cured MTA orAngelus MTA. Five animals from each group were injected with calcein on day 7, alizarin on day 14, and oxytetracycline on day 21. On day 30, these animals were killed, and the right hemimaxillas were removed and histologically processed. Half of the maxillas were processed and stained with hematoxylin and eosin. The remaining maxillas were processed for fluorescence anal- ysis and stained with Stevenel blue and alizarin red. New bone was histomorphometrically evaluated using a Merz grid.Results: The light-cured MTA presented a similar response when compared with Angelus MTA; it was char- acterized by a mild inflammatory response and complete bone healing. In the light-cured MTA group, the fluores- cence areas were more evident at 21 days, showing an increase in bone formation. However, dystrophic mineralization was observed only with Angelus MTA. Conclusions: It was concluded that both materials present a similar inflammatory response and bone heal- ing,butdystrophic mineralization was observed only with Angelus MTA. (J Endod 2011;37:250–254) Key Words Biocompatibility, fluorochromes, inflammation, mineral trioxide aggregate M ineral trioxide aggregate (MTA) was introduced in 1993 (1). It m material in capping of the dental pulp, root-end closure, repairin tion, and apical surgery (2). In addition, in vivo studies showed that MTA induces mineralized tissue formation such as dentin and cementum-like tiss Its biomineralization process leads to the formation of an interfacial layer with tag-like structures at the cement-dentin interface and positively influenced strength (12). MTA also has insignificant arsenic amounts in its com Despite its favorable characteristics, MTA has a short working ti handling and insertion, and requires additional moisture to activate experimental light-cure MTA has been developed to have similar pr also better working properties. Although this experimental material positive characteristics, there is only one study that evaluates the s reaction after its implantation (15), showing its similarity with Ange this material is lacking in information regarding the bone healing. Thus, the aim of this study was to evaluate by histological and fl the rat alveolar tissue response to implanted polyethylene tubes fill MTA or Angelus MTA. Materials and Methods Thirty-three–month-old male Wistar Albino rats, weighing betwe were used. The animals were housed in temperature-controlled roo water and food ad libitum. The care of the animals was performed a c¸atuba School ofDentistry-UNESP Ethical Committee, which approved the project before the beginning of the experiments. The rats were anesthetized with ketamine (87 mg/kg Francotar; Ind e Com Ltda, Roseira, Brasil) and xylazine (13 mg/kg Rompum; B ~ ao Paulo, Brazil) administered intramuscularly and were divided into three eq cure MTA (Bisco, IL), Angelus MTA, and control. Thirty polyethylene tubes (Abbott Laboratories of Brazil, Sao Pau a 1.0-mm internal diameter, 1.6-mm external diameter, and 3.0-mm of their openings sealed with 1 mm of gutta-percha (Hygenic-DFL, A sterilization in ethylene oxide. Two groups of 10 tubes each were fil materials, and 10 remained empty to be used as controls. The materials were handled according to the manufacturer’s rec and inserted into 10 polyethylene tubes. The light-cure MTA was cu with a light-cure unit (Ultralux-Dabi Atlante, Ribeir ~ ao Preto, Brazil). Each animal had right upper incisor extracted by using special instruments (16), and after hemostasis the implants were inserted into the depth of the socket. The gingiva with nonresorbable silk 4-0 sutures (Ethicon, Somerville, NJ). Fluorescent bone markers were injected in each animal for the s remodeling surround the tube opening. Calcein green, alizarin red, hydrochloride were injected after 7 days, 14 days, and 21 days after implantation From the Department of Endodontics, Arac¸ atuba School of Dentistry, University of Estadual Paulista, S ~ ao Paulo, SP, Brazil. Address requests for reprints to Dr Jo ~ ao Eduardo Gomes- Filho, Department of Endodontics, Arac¸ atuba Schoolof Dentistry, University of Estadual Paulista, R Jose Bonif acio, 1193 Arac¸ atuba, S ~ ao Paulo, Brazil. E-mail address: joao@foa. unesp.br. 0099-2399/$ - see front matter Copyright ª 2011 American Association of Endodontists. doi:10.1016/j.joen.2010.11.005 Basic Research—Technology 250 Gomes-Filho et al. JOE — Volume 37, Number 2, February 201