Effect of drying time of 3-methacryloxypropyltrimethoxysilane on the shear bond strength of a composite resin to silica-coated base/noble alloys.
OBJECTIVE
In this in vitro study, the effect of various drying (surface reaction) times of a commercial silane, other than that recommended by the manufacturer (at least 5 min), on the bond strength between the resin composite and silica coated base and noble alloys was evaluated.


METHODS
A total of 112 disc specimens (9 mm diameter and 0.5 mm thickness) were cast out of two types of alloy designed for ceramic firing, one of which was a noble (Degunorm) (gold-silver-platinum) and the other a base alloy (Wiron 99) (nickel-chromium-molybdenum). The specimens were assigned to two main groups according to each alloy type. These two main groups were further divided into seven subgroups, having eight specimens each. The specimens of both alloy types were air-abraded with 30 microm silica (SiO2) coated alumina (Al2O3) (CoJet-Sand, ESPE, Seefeld, Germany). The conditioned surfaces were coated with 3-methacryloxypropyltrimethoxysilane (MPS) and were allowed to react and dry for 1, 2, 3, 4, 5, 6, and 7 min, respectively, before the opaquer was applied. Immediately after the waiting periods for the silane to dry, first opaquer and then resin composite were applied. After storage in water for 30 days at 37 degrees C and thermocycling (5000 cycles, 5-55 degrees C), shear tests were performed using the universal testing machine at a crosshead speed of 0.5 mm/min.


RESULTS
Analysis of data showed no significant difference in bond strength for any silane drying and reaction period for both base and noble alloys between 1 and 7 min (ANOVA, P = 0.05) (Degunorm: 5.8 - 7.4 MPa and Wiron 99: 7.2 - 10.2 MPa, respectively). Bond strengths of resin composite to base alloys were significantly higher than those to noble alloys at 2, 3 and 5 min (P = 0.0045, P = 0.05, P = 0.002, respectively).


CONCLUSIONS
In order to optimize the flow of laboratory work, the silane solution drying time might be reduced to 1 min for both base and noble alloys.
Ozcan
Mutlu
M
Department of Dentistry and Dental Hygiene, Faculty of Medical Sciences, University of Groningen, Antonius Deusinglaan 1, NL-9713 AV, The Netherlands. mutluozcan@hotmail.com
Matinlinna
Jukka P
JP
Vallittu
Pekka K
PK
Huysmans
Marie-Charlotte
MC
D000704:Analysis of Variance; D020099:Coated Materials, Biocompatible; D003188:Composite Resins; D003722:Dental Alloys; D001840:Dental Bonding; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents; D003890:Desiccation; D008422:Materials Testing; D008689:Methacrylates; D033081:Shear Strength; D012821:Silanes; D012822:Silicon Dioxide; D018709:Statistics, Nonparametric; D013997:Time Factors
D020099:Coated Materials, Biocompatible; D003188:Composite Resins; D003722:Dental Alloys; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D012821:Silanes; C477352:Sinfony composite resin; C017492:methacryloxypropyltrimethoxysilane; D012822:Silicon Dioxide