Evaluation of discolouration of some composite restorative materials

ABSTRACT

This in-vitro study was conducted to investigate the stain resistance of direct composite resin restorative materials with different polishing systems [diamond finishing and polishing burs, aluminium oxide disks and abrasive impregnated disks] in comparison to the material cured against a mylar strip. The composite resin materials investigated included Clearfil AP-X [hybrid], Filtek Z-250 [hybrid], Definite [Ormocer], and Silux Plus [microfill]. Forty disk specimens [10mm x 2mm] of each composite resin were prepared. Ten mylar cured specimens were assigned for each polishing system and ten were used as controls with no further treatment after curing. A spectrophotometer [Spectraflash 500] was used to determine the initial colour and the colour change after one week immersion. All specimens were stored in tea separately for one week at 39[degree sign] C. Post immersion colour measurements were undertaken to assess colour change [delta E]. One way ANOVA showed that there was statistically significant difference between the different composites and the polish groups for discoloration at p<0.05. All the composites tested showed significant discoloration when polished with Diamond burs. The least discoloration was found when specimens were polished with soflex except with Z-250 which discoloured less under mylar than soflex but the difference was not significant. Among the materials tested AP-X showed the least discoloration