Tuesday, July 30, 2013

Effect of brushing and accelerated ageing on colour stability and surface roughness of composites

Available online 11 July 2013

Abstract

Objectives

The aim of this study was to evaluate the effect of brushing and artificial accelerated ageing (AAA) on colour stability and surface roughness of aesthetic restorative materials.

Methods

One hundred and twenty specimens (12 mm diameter × 2 mm thick), 40 of each material (n = 8) were obtained using nanosized composite Z350 (3M ESPE), nanohybrid composite Tetric N-Ceram (Ivoclar Vivadent) and ceramic IPS e.max Ceram (Ivoclar Vivadent), as control. Initial colour (Spectrophotometer PCB 6807) and surface roughness (Surfcorder SE 1700) readouts were taken and the samples were separated into five groups (n = 8) and treated as follows: Group 1: mechanical brushing with dentifrice RDA* 68 (Colgate), Group 2: mechanical brushing with dentifrice RDA* 180 (Colgate Total Plus Whitening), Group 3: AAA, Group 4: AAA followed by mechanical brushing with dentifrice RDA* 68 and Group 5: AAA followed by mechanical brushing with dentifrice RDA* 180. Mechanical brushing was performed for 205 min and AAA for 480 h; new colour and surface roughness readouts were taken. Data were statistically analyzed (two-way ANOVA repeated measures, Bonferroni test, p < 0.05).

Results

Dentifrice abrasiveness was not significant for colour change and surface roughness. When submitted to AAA+brushing, the colour stability of Tetric was statistically significant (p < 0.05) with both dentifrices and with dentifrice RDA* 180 for Z350. The roughness was different (p < 0.05) for Z350 when brushed with RDA* 68 after AAA.

Conclusions

Dentifrice abrasiveness did not interfere in the ability to remove stains and roughness from aged samples. However, staining is material-dependent.

Clinical significance

The abrasiveness of dentifrice does not change the colour and surface roughness of the composites and does not help to remove surface stains from the aged samples.

No comments: