Evaluation of the flexural strength and elastic modulus of resins used for temporary restorations reinforced with particulate glass fibre.
OBJECTIVE
The flexural strength and the elastic modulus of acrylic resins, Dencor, Duralay and Trim Plus II, were evaluated with and without the addition of silanised glass fibre.


METHODS
To evaluate the flexural strength and elastic modulus, 60 test specimens were fabricated with the addition of 10% ground silanised glass fibres for the experimental group, and 60 without the incorporation of fibres, for the control group, with 20 test specimens being made of each commercial brand of resin (Dencor, Duralay and Trim Plus II) for the control group and experimental group. After the test specimens had been completed, the flexural strength and elastic modulus tests were performed in a universal testing device, using the three-point bending test. For the specimens without fibres the One-Way Analysis of Variance and the complementary Tukey test were used, and for those with fibres it was not normal, so that the non-parametric Mann-Whitney test was applied.


RESULTS
For the flexural strength test, there was no statistical difference (p > 0.05) between each commercial brand of resin without fibres [Duralay 84.32(±8.54), Trim plus 85.39(±6.74), Dencor 96.70(±6.52)] and with fibres (Duralay 87.18, Trim plus 88.33, Dencor 98.10). However, for the elastic modulus, there was statistical difference (p > 0.01) between each commercial brand of resin without fibres [Duralay 2380.64 (±168.60), Trim plus 2740.37(±311.74), Dencor 2595.42(±261.22)] and with fibres (Duralay 3750.42, Trim plus 3188.80, Dencor 3400.75).


CONCLUSIONS
The result showed that the incorporation of fibre did not interfere in the flexural strength values, but it increased the values for the elastic modulus.
Orsi
Iara Augusta
IA
Department of Dental Materials and Dentures at the Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil. iaraorsi@forp.usp.br
Soares
Rodrigo Gonçalves
RG
Villabona
Camilo Andrés
CA
Panzeri
Heitor
H
D000180:Acrylic Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003794:Dental Restoration, Temporary; D003799:Dental Stress Analysis / Q000295:instrumentation; D055119:Elastic Modulus; D004853:Epoxy Resins / Q000737:chemistry; D005898:Glass / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008768:Methylmethacrylates / Q000737:chemistry; D018583:Pliability; D011109:Polymethacrylic Acids / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties
D000180:Acrylic Resins; D003764:Dental Materials; D004853:Epoxy Resins; D008768:Methylmethacrylates; D011109:Polymethacrylic Acids; D012821:Silanes; C009753:fiberglass; C091347:vinyl ethyl methacrylate; C034578:Duralay; C009931:poly(ethylmethacrylate); D019904:Polymethyl Methacrylate