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Polymerization stress, flow and dentine bond strength of two resin-based root canal sealers
S F C Souza1, A C Bombana, C Francci
1School of Dentistry, Federal University of Maranhão, São Luiz, MA 65085-580, Brazil. sosocarvalho@usp.br
Aim:
To compare two resin-based root canal sealers (AH Plus and dual cure Epiphany) in terms of flow, polymerization stress and bond strength to dentine.
Methodology:
Flow was evaluated by measuring the diameter of uncured discs of sealer (0.5 mL) after 7 min compression (20N) between two glass plates (n = 5). Polymerization stress was monitored for 60 min in 1-mm thick discs bonded to two glass rods (Ø = 5 mm) attached to a universal testing machine (n = 3). Bond strength was analyzed through micropush-out test (n = 10) and failure mode was examined with scanning electron microscope (100x and 2500x). Data were statistically analyzed using the Student's t-test (alpha = 0.05).
Results:
Polymerization stress was 0.32 +/- 0.07 MPa for Epiphany self-cure, 0.65 +/- 0.08 MPa for Epiphany light-cure and zero for AH Plus (P < 0.05). Flow data and bond strength values were 30.9 +/- 1.1, 28.6 +/- 0.7 mm and 6.3 +/- 5.3, 17.8 +/- 7.5 MPa for Epiphany and AH Plus, respectively (P < 0.001). Failure mode was predominantly cohesive in the sealer for both materials.
Conclusions:
Epiphany had higher flow and polymerization stress and lower bond strength values to dentine than AH Plus. In view of these findings it can be implied that AH Plus would provide a better seal.