The osteogenic effects of mineral trioxide aggregate, and modified mineral trioxide aggregate with the addition of silicon and calcium, on normal human osteoblast cells

PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.Thesis (MSD)--Boston University Goldman School of Dental Medicine, 2007 (Endodontics).Includes bibliography: leaves 98-109.An important requirement for dental materials placed in direct contact with living tissues is the regeneration or repair of those surrounding tissues. Mineral Trioxide Aggregate (MTA), a cement-type material introduced in the dental field in the mid 1990s, has gained much popularity. MTA was initially recommended as a root-end filling material or a perforation repair material. It has since been widely investigated for its variety of potential applications such as an apical barrier in teeth with immature apices, repair of root perforation, root-end filling, direct pulp capping and pulpotomy. Studies have demonstrated that MTA is a unique material because of its ability to promote regeneration of periradicular tissues (Schwartz, Mauger et al. 1999; Torabinejad and Chivian 1999; Giuliani, Baccetti et al. 2002) and superior biocompatibility (Torabinejad, Hong et al. 1995; Torabinejad, Pitt Ford et al. 1997). Tissue regeneration is an important characteristic for a material to be suitable in endodontic surgical procedures or for other procedures where living tissues are directly involved. In order to improve regeneration potential, researchers have looked at ways to stimulate osteogenic activity when a bone defect was detected adjacent to the sealing material. Ions released from various materials were found to stimulate osteogenic activity. Silicon ion was demonstrated to have osteogenic potential. Silicon ion can be released from bioactive glasses and serves as a signal for osteoblasts. In the Biomaterial Laboratory of Dr. Chou at Boston University, the effects of such silicon ions are being investigated. An addition of 15% silicon by weight to MRA was previously reported for its osteogenic effects on osteoblast cells (Dr. Tam et al.). Various percentage of silicon added to the MTA or other ions, such as calcium, were however not investigated for their potential in further stimulating osteogenic responses in human osteoblast cells. In the in vitro study herein reported, two different modifications were made to conventional white MTA. The first one consisted of the addition of 30% Silicon (SiO2) by weight to the MTA powder (MTA+Si). The second one consisted of the addition of 30% Bioactive Inorganic Element BIE) by weight to the MTA powder. This second modification added 6% Si and 4.5% Ca by weight to the MTA. The abbreviation MTA+BIE is used to describe this modification. Silicon and Calcium are two elements known for their ability to signal and selectively stimulate osteogenic activity. [TRUNCATED