Correlation between flexural and indirect tensile strength of resin composite cements.
BACKGROUND
To evaluate a potential correlation between flexural strength and indirect tensile strength in assessing the mechanical strength of resin composite cements.


METHODS
Flexural strength (n = 5) and indirect tensile strength (n = 5) of 7 resin composite cements (RelyX Unicem 2 Automix [RXU], Panavia SA [PSA], Clearfil SA [CSA], Panavia F2.0 [PF2], Multilink Implant [MLI], DuoCem [DCM], Panavia 21 [P21]) were determined. Specimens were either auto-polymerized or dual-cured (except P21) and stored in water at 37 °C for 1 day prior to measurement. Flexural and indirect tensile strength of 4 cements (RXU, PSA, PF2, MLI) was additionally measured directly after curing and after 96 h water storage at 37 °C.


RESULTS
Except for PF2, dual-cured specimens achieved higher flexural strength than auto-polymerized specimens. In the indirect tensile strength test differences in auto-polymerized and dual-cured specimens were only detected for RXU and DCM. A general non-linear correlation was found between flexural and indirect tensile strength values. However, strength values of auto-polymerized and dual-cured specimens did not generally correlate.


CONCLUSIONS
Flexural strength and indirect tensile strength of resin composite cements are correlated. At high strength values the indirect tensile test is less sensitive than the flexural test. The results suggest that the indirect tensile test may only be recommended as a screening test especially for low or medium strength resin composite cements.
Division of Dental Materials and Engineering, Clinic for Reconstructive Dentistry and Temporomandibular Disorders, University Hospital of Dental Medicine, University of Basel, Hebelstrasse 3, 4056, Basel, Switzerland.
Gianluca
G
Cassina
Division of Dental Materials and Engineering, Clinic for Reconstructive Dentistry and Temporomandibular Disorders, University Hospital of Dental Medicine, University of Basel, Hebelstrasse 3, 4056, Basel, Switzerland.
Jens
J
Fischer
Division of Dental Materials and Engineering, Clinic for Reconstructive Dentistry and Temporomandibular Disorders, University Hospital of Dental Medicine, University of Basel, Hebelstrasse 3, 4056, Basel, Switzerland. nadja.rohr@unibas.ch.
Nadja
http://orcid.org/0000-0002-1218-4519
N
Rohr
D003188:Composite Resins / Q000494:pharmacology*; D003799:Dental Stress Analysis / Q000379:methods*; D006801:Humans; D008422:Materials Testing / Q000379:methods*; D010710:Phosphates / Q000494:pharmacology; D019279:Resin Cements / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D013718:Tensile Strength
C581302:Clearfil SA; D003188:Composite Resins; C093719:Panavia TPN-S; D010710:Phosphates; C483701:Rely X Unicem; D019279:Resin Cements
Aging; Auto-polymerizing cement; Curing mode; Dual-curing cement; Flexural strength; Indirect tensile strength; Resin composite cement