Correlation of bond strength with surface roughness using a new roughness measurement technique.
OBJECTIVE
The correlation between shear bond strength and surface roughness was investigated using new surface measurement methods.


METHODS
Bonding agents and associated resin composites were applied to set amalgam after mechanically roughening its surface. Surface treatments were noe (as set against glass), 80 grit, and 600 grit abrasive paper. Surface roughness (R(a) as measured parallel and perpendicular (+) to the direction of the polishing scratches and true profile length were measured. A knife-edge was applied (rate = 2.54 mm/min) at the bonding agent/amalgam interface of each sample until failure.


RESULTS
Coefficients of determination for mean bond strength vs either roughness (R(a), of profile length were significantly higher for measurements in parallel directions than for those measurements in (+) directions. The shear bond strength to set amalgam for a PENTA-containing adhesives system (L.D. Caulk Division) was not significantly different from that of a PENTA-free adhesive (3M Dental Products Division), even though PENTA has been reported to increase bond strength to nonprecious metals.


CONCLUSIONS
The shear bond strength of resin composite to amalgam is correlated to surface roughness when it is measured parallel to the polishing scratches. This correlation is significantly lower when surface roughness is measured in the typical manner, perpendicular to the polishing scratches.
Winkler
M M
MM
Department of Restorative Dentistry, Indiana University, School of Dentistry, Indianapolis 46202, USA.
Moore
B K
BK
D003722:Dental Alloys / Q000737:chemistry; D003723:Dental Amalgam / Q000737:chemistry; D001840:Dental Bonding; D003775:Dental Polishing; D017220:Dentin-Bonding Agents; D008422:Materials Testing / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements; D013499:Surface Properties; D013718:Tensile Strength
D003722:Dental Alloys; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C062652:Prisma Universal Bond; C033470:Dispersalloy; D003723:Dental Amalgam