In-Vitro Comparative Adhesion Evaluation of Bioceramic and Dual-Cure Resin Endodontic Sealers Using SEM, AFM, Push-Out and FTIR  
[PERSON]  
1 Department of Odontology, Endodontics and Oral Pathology, \"[PERSON]\" University of Medicine and Pharmacy, 33 Motilor Street, 400001 Cluj-Napoca, Romania; [EMAIL_ADDRESS] (R.M.C. );  
[EMAIL_ADDRESS] (D.H.J. );  
[EMAIL_ADDRESS] (A.G.D. );  
[EMAIL_ADDRESS] (D.I.R. );  
[EMAIL_ADDRESS] (O.P.) 2 Department of Polymeric Composites, \"[PERSON]\" Institute of Research in Chemistry, \"Babes Bolyai\" University, 30 Fantanlee Street, 400294 Cluj-Napoca, Romania;  
[EMAIL_ADDRESS] (M.M. );  
[EMAIL_ADDRESS] (D.P.) 3  
Footnote 1: email: {[EMAIL_ADDRESS], (D.H.J. );  
4 Department of Pedodontics, \"[PERSON]\" University of Medicine and Pharmacy, 31 Avram Iancu Street, 400083 Cluj-Napoca, Romania; [EMAIL_ADDRESS] (D.I.R. );  
5  
Footnote 2: email: {[EMAIL_ADDRESS], (D.H.J. );  
5
Footnote 3: email: {[EMAIL_ADDRESS], (D.H.J. );  
6
Footnote 4: email: {[EMAIL_ADDRESS], (D.H.J. );  
7
Footnote 5: email: {[EMAIL_ADDRESS], (D.H.J. );  
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Footnote 6: email: {  
There is a great variety of materials used in endodontic practice and the newly developed bioceramic-based root canal sealers have improved physicochemical properties (biocompatibility, lack of toxicity and grip contraction, chemical stability). In endodontics, bioceramic-based materials do not cause a significant inflammatory response in case of excessive apical extrusion. Another advantage is the ability to form hydroxyapatite (during adhesion) and bond to dental tissues (dentin). Superior adjustment to the upper walls is also due to its hydrophilic nature. The bioceramic sealers can penetrate into the dental tubules and polymerize, forming a hybrid layer. The formation of the hybrid layer is favored by the existence of hydrophilic monomers and solvent in the bioceramic sealer composition [9]. The adhesion of bioceramic root canal sealers consists in hydrated calcium silicate powder that results in calcium silicate hydrate gel and calcium hydroxide [10]. Endodontic filling using urethane dimethacrylate resin is claimed to create a tight seal with the dentinal tubules within the root canal system. In essence, it produces a \"monoblock\" effect, where the core material, sealer and dentinal tubules become a single solid structure [11]. The introduction of a new dual cure resin based self-etch root canal filling material with similar bond strength to dentin and with a biocompatible polymer matrix has proven promising in what concerns the design of new materials for various applications in endodontic [6; 7; 8; 9; 10; 11; 12; 13; 14; 15]. Scanning electron microscopy is one of the first and most used methods for the study of mechanism implied in the adhesion process. Using SEM micrographs, surface details regarding corrosion and resin infiltration into dentinal tubules can be investigated [16; 17; 18; 19]. Atomic force microscopy (AFM) is an important tool for biological sample evaluation due to its surface evaluation capacity in liquid environment. Currently this is the only available technique that directly provides structural, mechanical and functional information on high resolution [20]. The push-out test provides a better assessment of adhesion than conventional shear tests, because the fracture takes place in parallel with the dentin-cement interface, which makes a true shear test with the parallel sides of the samples. It has the advantage that it more closely simulates the clinical condition [21; 22; 23]. We have developed an in vitro comparative study in order to evaluate the formation of the hybrid layer and sealant infiltration in radicular tubules for: an experimental dual cure resin based endodontic sealer (E1-DCR), an experimental bioceramic based sealer (E2-BC), compared to two commercial widespread resin-based material (Real Seal and TotalFill BC (FFG Germany)) using SEM and AFM analysis. The interfacial forces and filling defects in the root canals were evaluated using push-out bond strength.