Abrasive wear of resin composites as related to finishing and polishing procedures.
OBJECTIVE
Finishing and polishing procedures may cause topographical changes and introduce subsurface microcracks in dental composite restoratives. Since both of these effects may contribute toward the kinetics of wear, the purpose of this study was to assess and correlate the wear and surface roughness of minifilled and nanofilled composites finished and polished by different methods.


METHODS
Specimens (n=10) made of a minifilled and a nanofilled composite were finished and polished with one of the four sequences: (1) tungsten carbide burs plus Al(2)O(3)-impregnated brush (CbBr) or (2) tungsten carbide burs plus diamond-impregnated cup (CbCp), (3) diamond burs plus brush (DmBr) or (4) diamond burs plus cup (DmCp). As a control, abrasive papers were used. After surface roughness had been quantified, three-body abrasion was simulated using the OHSU wear machine. The wear facets were then scanned to measure wear depth and post-testing roughness. All sets of data were subjected to ANOVA and Tukey's tests (alpha=0.05). Pearson's correlation test was applied to check for the existence of a relationship between pre-testing roughness and wear.


RESULTS
Significantly smoother surfaces were attained with the sequences CbBr and CbCp, whereas DmCp yielded the roughest surface. Regardless of the finishing/polishing technique, the nanofilled composite exhibited the lowest pre-testing roughness and wear. There was no correlation between the surface roughness achieved after finishing/polishing procedures and wear (p=0.3899).


CONCLUSIONS
Nano-sized materials may have improved abrasive wear resistance over minifilled composites. The absence of correlation between wear and surface roughness produced by different finishing/polishing methods suggests that the latter negligibly influences material loss due to three-body abrasion.
Division of Biomaterials and Biomechanics, School of Dentistry, Oregon Health and Sciences University, 611 SW Campus Drive, Portland, OR 97239, USA. cturssi@yahoo.com
Cecilia P
CP
Turssi
Jack L
JL
Ferracane
Mônica C
MC
Serra
D000704:Analysis of Variance; D003188:Composite Resins; D003775:Dental Polishing / Q000295:instrumentation* / Q000379:methods*; D019554:Dental Restoration Wear; D018130:Diamond; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D011897:Random Allocation; D018709:Statistics, Nonparametric; D013499:Surface Properties; D017973:Tungsten Compounds
D003188:Composite Resins; C474035:Filtek Supreme; C444701:Filtek Z250; D017973:Tungsten Compounds; C002802:tungsten carbide; D018130:Diamond