Shear bond strength between a polyester-based root canal filling material and a methacrylate-based sealer with an intermediate layer of fiber-reinforced resin-based material.
OBJECTIVE
To investigate the effects of an interfacial fiber-reinforced resin-based material (FRRM) application and different light-curing modes on the bond strength of a thermoplastic synthetic polymer-based root canal filling material (Resilon) to a methacrylate-based sealer (Epiphany).


METHODS
One hundred Resilon disks were prepared and divided into two experimental groups: 1. application of FRRM (EverStick Net) on the Resilon surface, and 2. Resilon alone (control). Following subsequent application of the Epiphany sealer, the specimens were randomly assigned into 3 subgroups according to the curing method employed: 1. chemical curing, 2. quartz-tungsten-halogen (QTH) light, and 3. light-emitting diode (LED). The latter two groups were further subdivided to test the effects of two different polymerization modes for each light-curing unit. Cured specimens were subjected to shear bond strength testing and the failure modes were examined. The data were analyzed with three-way analysis of variance (ANOVA).


RESULTS
Regardless of the curing method tested, application of FRRM at the interface significantly increased the bond strength of Resilon to Epiphany (p < 0.001). Bond strength values (MPa) were as follows (mean +/- SD): 1. chemical curing with FRRM= 3.0 +/- 0.4, without FRRM = 1.2 +/- 0.3; 2. QTH: a) standard mode with FRRM = 8.6 +/- 0.6, without FRRM = 5.5 +/- 0.9; b) ramp mode with FRRM = 8.0 +/- 1.0, without FRRM = 5.3 +/- 1.4; 3. LED: a) standard mode with FRRM = 8.8 +/- 1.1, without FRRM = 5.4 +/- 1.0; b) exponential mode with FRRM = 8.5 +/- 1.0, without FRRM = 4.6 +/- 0.6. Although light curing of specimens significantly increased the bond strength of Resilon to Epiphany (p < 0.001), the type of light-curing unit and different curing modes had no significant influence on bond strength (p = 0.852 and p = 0.776, respectively).


CONCLUSIONS
The highest bond strength values were obtained when the FRRM was used at the interface and the sealer was light cured.
Nagas
Emre
E
Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey. enagas@hacettepe.edu.tr
Cehreli
Zafer C
ZC
Durmaz
Veli
V
Vallittu
Pekka K
PK
Lassila
Lippo V J
LV
D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental / Q000145:classification; D001840:Dental Bonding; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011091:Polyesters / Q000737:chemistry*; D011108:Polymers / Q000145:classification; D012387:Root Canal Filling Materials / Q000737:chemistry*; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties
D003188:Composite Resins; C444701:Filtek Z250; D008689:Methacrylates; D011091:Polyesters; D011108:Polymers; D012387:Root Canal Filling Materials; C486893:epiphany sealer; C496140:everStick; C486892:resilon sealer