A Spectrophotometric Analysis Of Staining Of Glass Ionomer Cements

Objectives: INTRODUCTION: The ability of a tooth-coloured restorative material to resist absorbing colour from food and drink is an important property of any glass ionomer cement. Maintenance of colour of restorative materials throughout the lifetime of the restoration is important for the success of treatment. One of the challenges facing clinicians is that aesthetic restorations need to be replaced relatively frequently since the staining/discolouration of aesthetic materials is common. AIM: The purpose of this research was to assess the colour stability of 3 glass-ionomer restorative materials when immersed in a staining broth.
Methods: Fifteen specimens for each material, Fuji II LC (GC); Riva Light Cure (SDI) and Photac Fil Quick Aplicap (3M ESPE) were prepared from Teflon rings (discs of 10mm diameter and 3mm thickness). A baseline colour measurement (L*a*b* scale) was recorded with a spectrophotometer (Konica Minolta) after storing the specimens in distilled water at 37°C for 7 days. Specimens were suspended in a staining broth for 4hrs, 8hrs, 24hrs and 7days. Three colour measurements each were recorded at these intervals. Colour differences between each interval were then calculated using the CIELAB formula, ΔE*(a*b*)=[(ΔL*)2+(Δa*)2 + ( Δb* )2 ]½.
Results: There was a significant difference in the Delta E values between Photoc, Riva and Fuji II (ANOVA test of means, p<0.05). When the overall discolouration differences were compared (ΔE*a*b*) the materials ranked as follows: Fuji II (6.57) < Riva (7.22) < Photac (12.07) when measured 24 hours after staining.
Conclusions: Within the limitations of this in-vitro study, Photac showed significantly more discolouration over time than the other materials tested.