Flexural modulus, flexural strength, and stiffness of fiber-reinforced posts.
BACKGROUND
The radiopacity degree of posts is not enough for adequate visualization during radiographic analyses. Glass fiber post with stainless steel reinforcement has been fabricated in an attempt to overcome this limitation.


OBJECTIVE
This study was designed to determine the influence of this metal reinforcement on the post mechanical properties.


METHODS
This study evaluated flexural modulus (E), flexural strength (sigma), and stiffness (S) of five different fiber post systems (n = 5): RfX (Reforpost Glass Fiber RX; Angelus, Londrina, PR, Brazil); RG (Reforpost Glass Fiber, Angelus); RC (Reforpost Carbon Fiber, Angelus); FP (Fibrekor Post; Jeneric Pentron Inc., Wallingford, CT, USA); and CP (C-Post; Bisco Dental Products, Schaumburg, IL, USA), testing the hypothesis that the insertion of a metal reinforcement (RfX) jeopardizes the mechanical properties of a glass fiber post. Posts were loaded in three-point bending using a testing machine with a crosshead speed of 0.5 mm/min.


RESULTS
The results were statistically analyzed using one-way ANOVA and Tukey's multiple range tests (a = 0.05). Mean and standard deviation values of E (GPa), s (MPa), and S (N/mm) were as follows: RfX: 10.8 +/- 1.6, 598.0 +/- 52.0, 132.0 +/- 21.9; RG: 10.6 +/- 1.0, 562.0 +/- 24.9, 137.8 +/- 5.5; RC: 15.9 +/- 2.4, 680.5 +/- 34.8, 190.9 +/- 12.9; FP: 10.9 +/- 1.4, 586.8 +/- 21.9, 122.4 +/- 17.3; CP: 6.3 +/- 1.7, 678.1 +/- 54.2, 246.0 +/- 41.7. Carbon fiber posts showed the highest mean s values (P < 0.05). In addition, RC showed the highest mean E value and CP showed the highest mean S value (P < 0.05).


CONCLUSIONS
The hypothesis was rejected since the metal reinforcement in the glass fiber post (RfX) does not decrease the mechanical property values. Posts reinforced with carbon fibers have a higher flexural strength than glass fiber posts, although all posts showed similar mechanical property values with dentin.
Novais
Veridiana R
VR
Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, MG, Brazil.
Quagliatto
Paulo S
PS
Bona
Alvaro Della
AD
Correr-Sobrinho
Lourenco
L
Soares
Carlos J
CJ
D000704:Analysis of Variance; D002244:Carbon; D000077482:Carbon Fiber; D003722:Dental Alloys; D003764:Dental Materials; D003799:Dental Stress Analysis; D055119:Elastic Modulus; D004548:Elasticity; D005898:Glass; D008422:Materials Testing; D018583:Pliability; D011176:Post and Core Technique / Q000295:instrumentation*; D012390:Root Canal Therapy / Q000295:instrumentation*; D013193:Stainless Steel; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical
D000077482:Carbon Fiber; D003722:Dental Alloys; D003764:Dental Materials; C009753:fiberglass; D013193:Stainless Steel; D002244:Carbon