Marginal Gaps between 2 Calcium Silicate and Glass Ionomer Cements and Apical Root Dentin Vladimir Biocanin, DDS, PhD,* † ÐorCe Antonijevic, DDS, PhD, ‡§ SrCan Po stic, DDS, PhD, k Dragan Ilic, DDS, PhD, Zorica Vukovic, PhD,** Marija Milic, PhD, # Yifang Fan, PhD, †† Zhiyu Li, PhD, ‡‡ Bozidar Brkovic, DDS, PhD, # and Marija Ðuric, MD, PhD ‡ Abstract Introduction: The outcome of periapical surgery has been directly improved with the introduction of novel material formulations. The aim of the study was to compare the retrograde obturation quality of the following materials: calcium silicate (Biodentine; Septo- dont, Saint-Maur-des-Fosses, France), mineral trioxide aggregate (MTA+; Cerkamed Company, Stalowa Wola, Poland), and glass ionomer cement (Fuji IX; GC Corporation, Tokyo, Japan). Methods: Materials’ wettability was calculated concerning the contact an- gles of the cements measured using a glycerol drop. Ce- ments’ porosity was determined using mercury intrusion porosimetry and micro–computed tomographic (mCT) imaging. Extracted upper human incisors were retro- filled, and mCT analysis was applied to calculate the vol- ume of the gap between the retrograde filling material and root canal dentin. Experiments were performed before and after soaking the materials in simulated body fluid (SBF). Results: No statistically significant dif- ferences were found among the contact angles of the studied materials after being soaked in SBF. The material with the lowest nanoporosity (Fuji IX: 2.99% and 4.17% before and after SBF, respectively) showed the highest values of microporosity (4.2% and 3.1% before and after SBF, respectively). Biodentine had the lowest value of microporosity (1.2% and 0.8% before and after SBF, respectively) and the lowest value of microgap to the root canal wall ([10 30] 10 3 mm 3 ). Conclusions: Biodentine and MTA possess certain advantages over Fuji IX for hermetic obturation of retrograde root canals. Biodentine shows a tendency toward the lowest marginal gap at the cement-to-dentin interface. (J Endod 2017;-:1–6) Key Words Calcium silicate, micro–computed tomographic imaging, porosity, root-end filling, wettability T he main goal of periapi- cal surgery is to remove pathological periradicular tissue and hermetically seal the root apex in 3 di- mensions (1). The litera- ture confirms that if an optimal apical seal is not achieved, restitutio ad in- tegrum may not occur (2–4). The outcome of periapical surgery has been directly improved with the introduction of tricalcium silicate material formulations (5–8). Mineral trioxide aggregate (MTA) has biocompatibility, radiopacity, and superior obturation quality compared with amalgam, Super EBA (Bosworth, Chicago, IL), and in- termediate restorative material cement (9, 10). MTA possesses adequate sealing ability preventing microbial contamination and its by-products (11–13). However, MTA has a long setting time and difficulties with handling and compacting into narrow and curved root canals. Biodentine (BD; Septodont, Saint-Maur-des-Fosses, France) is a novel formulation of tricalcium silicate–based cement designed to overcome these drawbacks. It presents excellent 3-dimensional (3D) apical obturation followed by the lowest level of microleakage in comparison with glass ionomers (GIs) and MTA (14). From a clinical point of view, hermetic obturation is directly correlated to bacterial leakage and, consequently, contamination of periapical tissues. First, bacterial leakage is significantly reduced if root-end filling material possesses low porosity (15). Porosity has a direct effect on the permeability of bacteria and their products into periapical tissues (16). Second, surface features of root-end filling material are related to its potential to adhere to surrounding dental tissue. High wettability of root-end filling materials is desired because a positive correlation has been found with the sealing ability and material penetration into dentinal tubules (17). The aim of this in vitro study was to evaluate the quality of 3D retrograde filling by comparing the wettability, the porosity of selected materials per se in clinically simulated conditions, and the volume of the gap at the material-dentin interface among GI and 2 From the *Faculty of Pharmacy and Health, University of Travnik, Travnik, Bosnia; † Faculty of Dentistry, University Business Academy, Novi Sad, Serbia; ‡ Laboratory for Anthropology, Institute for Anatomy, School of Medicine, § Laboratory for Atomic Physics, Institute for Nuclear Science ‘‘Vinca,’’ k Department of Prosthodontics, School of Dental Medicine, Department of Endodontics, School of Dental Medicine, and # Department of Oral Surgery, School of Dental Medicine, University of Belgrade, Belgrade, Serbia; **Department of Catalysis and Chemical Engineering, Institute of Chemistry, Technology and Metallurgy, Belgrade, Serbia; †† School of Physical Ed- ucation and Sport Science, Fujian Normal University Fuzhou, Fujian, China; and ‡‡ College of Foreign Studies, Jinan University, Guangzhou, Guangdong, China. Address requests for reprints to Prof Marija Ðuri c, Laboratory for Anthropology, Institute of Anatomy Faculty of Medicine, University of Belgrade, Dr Subotica 4/2, 11000 Belgrade, Serbia. E-mail address: marijadjuric5@gmail.com 0099-2399/$ - see front matter Copyright ª 2018 American Association of Endodontists. https://doi.org/10.1016/j.joen.2017.09.022 Significance Adequate 3D obturation is a crucial prerequisite for the prevention of the postoperative spread of periapical infection. Here, we document that Biodentine presents certain microstructural advan- tages over MTA+ and Fuji IX in retrograde root canal surgery. Basic Research—Technology JOE — Volume -, Number -, - 2017 Marginal Gaps between Silicate Cements and Root Dentin 1