Microtensile bond strength between a quartz fiber post and a resin cement: effect of post surface conditioning.
OBJECTIVE
To test the bond strength between a quartz-fiber-reinforced composite post (FRC) and a resin cement. The null hypothesis was that the bond strength can be increased by using a chairside tribochemical silica-coating system.


METHODS
Thirty quartz-FRCs (Light-Post) were divided into 3 groups according to the post surface treatment: G1) Conditioning with 32% phosphoric acid (1 min), applying a silane coupling agent; G2) etching with 10% hydrofluoric acid (1 min), silane application; G3) chairside tribochemical silica coating method (CoJet System): air abrasion with 30-microm SiOx-modified Al2O3 particles, silane application. Thereafter, the posts were cemented into a cylinder (5 mm diameter, 15 mm height) with a resin cement (Duo-Link). After cementation, the specimens were stored in distilled water (37 degrees C/24 h) and sectioned along the x and y axes with a diamond wheel under cooling (Lab-cut 1010) to create nontrimmed bar specimens. Each specimen was attached with cyanoacrylate to an apparatus adapted for the microtensile test. Microtensile testing was conducted on a universal testing machine (1 mm/min). The data obtained were submitted to the one-way ANOVA and Tukey test (alpha = 0.05).


RESULTS
A significant influence of the conditioning methods was observed (p < 0.0001). The bond strength of G3 (15.14 +/- 3.3) was significantly higher than the bond strengths of G1 (6.9 +/- 2.3) and G2 (12.60 +/- 2.8) (p = 0.000106 and p = 0.002631, respectively). Notwithstanding the groups, all the tested specimens showed adhesive failure between the resin cement and FRC.


CONCLUSIONS
The chairside tribochemical system yielded the highest bond strength between resin cement and quartz-fiber post. The null hypothesis was accepted (p < 0.0001).
Valandro
Luiz Felipe
LF
Dept of Restorative Dentistry, Dental School, Federal University of Santa Maria, Brazil. lfvalandro@hotmail.com
Yoshiga
Silvia
S
de Melo
Renata Marques
RM
Galhano
Graziela Avila Prado
GA
Mallmann
Andre
A
Marinho
Cleverson Porto
CP
Bottino
Marco Antonio
MA
D000134:Acid Etching, Dental / Q000379:methods; D020906:Air Abrasion, Dental; D000537:Aluminum Oxide / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation*; D011791:Quartz / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
D003188:Composite Resins; C431350:Duo-Link; D008689:Methacrylates; D010756:Phosphoric Acids; D019279:Resin Cements; D012821:Silanes; D011791:Quartz; C017492:methacryloxypropyltrimethoxysilane; D012822:Silicon Dioxide; C030242:phosphoric acid; D000537:Aluminum Oxide; D006858:Hydrofluoric Acid