Bonding indirect resin composites to metal: part 2. Effect of alloy surface treatment on elemental composition of alloy and bond strength.
OBJECTIVE
This laboratory study compared the effect of different surface treatments of a medium-gold, high-noble alloy on the shear bond strength of an indirect, highly filled resin composite to the alloy and on the elemental composition of the alloy surface.


METHODS
Ninety disks, cast in a medium-gold, high-noble porcelain-fused-to-metal alloy (V-Deltaloy), received three different surface treatments: sandblasting with 50-microm Al2O3 (group 1) or 250-microm Al2O3 (group 2) and chemical agents, or with 250-microm Al2O3 without chemical agents (group 3) prior to bonding of an indirect resin composite (Artglass, and chemical agents Siloc-pre and Siloc-bond). The specimens were tested in shear, half of them after 24-hour dry storage at room temperature and the rest after 10-day storage in normal saline solution at 37 degrees C and thermocycling (2,500 cycles between 5 and 55 degrees C). Morphologic and qualitative changes on the alloy surface after sandblasting with 50- or 250-microm Al2O3 were examined by SEM using EDS analysis and compared with polished specimens. Statistical analysis was performed using two-factor ANOVA.


RESULTS
The mean shear bond strengths (in MPa) after dry or wet storage and thermocycling were 29 and 24 for group 1, 21 and 18 for group 2, and 17 and 12 for group 3, respectively; there was a statistically significant difference among the groups. Sandblasting of the alloy surface led to statistically significant changes in elemental composition. These changes were of greater magnitude when 50-microm Al2O3 particles were used.


CONCLUSIONS
The particle size used for sandblasting influences the shear bond strength between a high-noble alloy and a highly filled indirect resin composite, as well as the elemental composition of the alloy surface.
Department of Fixed Prosthesis and Implant Prosthodontics, School of Dentistry, Aristotle University, Thessaloniki, Greece. Lpetridis@the.forthnet.gr
Haralampos
H
Petridis
Pavlos
P
Garefis
Hiroshi
H
Hirayama
Nikolaos M
NM
Kafantaris
Petros T
PT
Koidis
D000537:Aluminum Oxide / Q000737:chemistry; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D003722:Dental Alloys / Q000032:analysis / Q000737:chemistry*; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry; D045662:Dental Etching; D004577:Electron Probe Microanalysis; D005899:Glass Ionomer Cements / Q000737:chemistry; D006047:Gold Alloys / Q000032:analysis / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000032:analysis / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D012821:Silanes / Q000737:chemistry; D012823:Silicate Cement / Q000737:chemistry; D012965:Sodium Chloride / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors
D003188:Composite Resins; D003722:Dental Alloys; D003738:Dental Cements; D005899:Glass Ionomer Cements; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; D012821:Silanes; C465121:Siloc; C111282:dental polyglass; D012823:Silicate Cement; D012965:Sodium Chloride; D000537:Aluminum Oxide