The influence of storage time and cutting speed on microtensile bond strength.
OBJECTIVE
The aim of this study was to verify the influence of the storage time and the cutting speed during specimen preparation on the bond strength of a single-bottle adhesive to dentin.


METHODS
A flat dentin surface was exposed in 36 human third molars. The adhesive system (Single Bond) was applied according to the manufacturer's instructions, and composite resin crowns (Z250) were constructed incrementally. Specimens were stored for 10 min, 24 h, or 1 week in distilled water at 37 degrees C before being longitudinally sectioned in both the "x" and "y" directions at different cutting speeds (0.5, 1.6, and 2.6 m/s) to obtain sticks with a cross-sectional area of approximately 0.8 mm2. The specimens were tested in a tensile load machine (0.5 mm/min) and the fracture mode analyzed. A two-way ANOVA with storage time (3 levels) and cutting speed (3 levels) as factors was used to compare the mean microtensile bond strengths.


RESULTS
Highly significant main effects and interaction (p < 0.0001) were detected. The highest mean bond strength was obtained with a storage time of 1 week and cutting speed of 2.6 m/s. The lowest mean was found when the specimens were prepared immediately after composite resin placement and sliced at 0.5 m/s.


CONCLUSIONS
Both the storage time and the cutting speed may affect the bond strength results. Therefore, these variables must be controlled in microtensile bond strength tests.
Reis
Alessandra
A
Assistant Professor, Department of Dental Materials and Operative Dentistry, University of Oeste de Santa Catarina, SC, Brazil. reis_ale@hotmail.com
Rocha de Oliveira Carrilho
Marcela
M
Schroeder
Marcos
M
Tancredo
Luciane Lima Franco
LL
Loguercio
Alessandro Dourado
AD
D000134:Acid Etching, Dental; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D001840:Dental Bonding; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008867:Microtomy / Q000379:methods; D013718:Tensile Strength; D013997:Time Factors
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate