| . |
The effect of tooth age on color adjustment potential of resin composite restorations.
J Dent. 2014 Sep 18;
Authors: Tanaka A, Nakajima M, Seki N, Foxton R, Tagami J
Abstract
OBJECTIVES: The purpose of this study was to investigate the effect of tooth age on color adjustment potential of resin composite restorations in human teeth.
METHODS: Twenty extracted human premolars with an A2 shade, extracted for orthodontic reasons from younger patients (20-28 yrs) (younger teeth) and periodontal reasons from older patients (45-69 yrs) (older teeth), were used in this study. Cylindrical shaped cavities (3.0mm depth; 2.0mm diameter) were prepared in the center of the crowns on the buccal surface. One of four resin composites of A2 shade (Kalore, KA; Solare, SO; Clearfil Majesty, MJ; Beautifil II, BF) was placed in the cavity, and the color was measured at four areas (0.4mm x 0.4 mm(2)) on the restored teeth (area 1; tooth area 1.0mm away from the border of resin composite restoration: area 2; tooth border area 0.3mm away from margin of resin composite restoration: area 3; resin composite border area 0.3mm away from margin of resin composite restoration: area 4; resin composite area at the center of resin composite restoration) using a spectrophotometer (Crystaleye). The color of each area was determined according to the CIELAB color scale. Color differences (ΔE*) between the areas of 1 and 2, 2 and 3, 3 and 4 and 1 and 4 were calculated, and also the ratio of ΔE*area2-3 to ΔE*area1-4 (ΔE*area2-3/1-4), ΔE*area3-4 to ΔE*area1-4 (ΔE*area3-4/1-4) and ΔE*area1-2 to ΔE*area1-4 (ΔE*area1-2/1-4) as a parameter of the color shift in resin composite restoration, were determined. Moreover, the light transmission characteristics of the resin materials and dentine discs from the younger and older teeth were measured using a goniophotometer. The data were statistically analyzed using two-way ANOVA, and Dunnett’s T3 and t-test for the post-hoc test.
RESULTS: ΔE*area2-3 (color difference between resin composite and tooth at the border) and ΔE*area1-4 (color difference between resin composite and tooth) of the older teeth groups were significantly larger than those of younger teeth groups (p<0.05). The ΔE*area2-3/1-4 (mis-match rate in color shifting at the border) of the older teeth groups was larger than that of the younger teeth groups (p<0.05). ΔE*area3-4/1-4 (color shifting rate of resin composite side) was significantly larger in older teeth than younger teeth (p<0.05), while ΔE*area1-2/1-4 (color shifting rate of tooth side), was significantly smaller in older teeth than younger teeth (p<0.05). In each tooth group, there were no significant differences in ΔE*area2-3, ΔE*area1-4, ΔE*area2-3/1-4, ΔE*area3-4/1-4 and ΔE*area1-2/1-4 between the materials (p>0.05). Analysis of the light transmission properties indicated that older dentine transmitted more light, while younger dentine exhibited greater light diffusion and transmitted less light.
CONCLUSIONS: The color shifting effects at the border of the resin composite restorations were influenced by the age of the tooth. This behavior might be influenced by the light transmission characteristics of dentine in restored teeth. Clinical Significance: The potential for color adjustment of resin composite restorations may be less in older teeth than younger teeth.
[cite source='pubmed']25242100[/cite]- as supplied by publisher]