The Effects of Different Spectrophotometric Modes on Colour Measurement of Resin Composite and Porcelain Materials.

OBJECTIVES: To investigate the influence of a number of controlled modes on the spectrophotometric analysis of the colour of resin composite and porcelain materials. METHODS: A total of 20 samples of commercially available resin composite, and 20 samples of commercially available porcelain materials in four different shades were produced (five samples for each shade). Colour was measured using a spectrophotometer (CM2600-d, Minolta Konica) set with different colour measuring modes namely, small aperture size (SAV) or large aperture size (MAV); specular component included (SCI), or excluded (SCE); 0% (UV-) or 100% UV illumination (UV+). Colour data were then compared using paired T-test. RESULTS: Colour coordinates measured with spectrophotometric modes set as 2° observation angle, SAV, SCI, and UV- were significantly different from those measured with 10° observation angle, MAV, SCE, and UV+ respectively in most cases for both materials. CONCLUSION: Different spectrophotometric modes (2 or 10 degrees observation angle, SAV or MAV aperture size, 0% or 100% UV, and SCI or SCE) significantly influenced the absolute colour measurements of resin composite and porcelain samples. CLINICAL SIGNIFICANCE: Measuring modes should be taken into consideration when comparing the results of absolute colour measurements of resin composite and dental porcelain materials.

The Effect of Try-In Paste and Resin Cement Shade on Colour Properties of Dental Veneers.

OBJECTIVES: The purpose of this study was to investigate how different shades of try-in pastes, uncured and cured resin cements affect the overall colour of porcelain veneer restorations. METHODS: A total of 90 porcelain veneers of shade Vita 1M1 VM7 and 0.6 mm thick were applied to bovine teeth using 3 shades of resin cement and their try-in paste produced by 3 manufacturers. RESULTS: Colour differences produced between the try-in pastes and the corresponding shades of cured resin cements ranged from (ΔE* 1.18-3.1). The colour differences between uncured and cured resins of the same shade ranged from (ΔE* 0.78 - 1.41). CONCLUSIONS: Different shades of try-in pastes and resin cements produced colour changes which are clinically useful in changing the colour of veneer restorations and therefore assist in colour matching to adjacent teeth. Clinically significant differences were noticed between try-in pastes and the cured resin of the same shade, however, there were relatively small changes measured between un-cured and cured resins. The colour match obtained by the try-in paste has to be treated with caution and further evaluation of the restoration made with the resin in place before curing is recommended.

Colour match between porcelain and porcelain-repairing resin composites.

The aim of this study was to evaluate the differences in colour between dental porcelain and porcelain-repairing resin composites. Porcelain discs were fabricated using four dentine shades in 1mm and 2mm thicknesses. Another series of discs was fabricated in 1mm and 2 mm thicknesses using three different brands of composite. Four single shades were used for the 1mm thick discs, and four single and 12 combined shades for the 2mm thick discs. The colour was measured using a spectrophotometer and colour differences deltaE* were calculated between samples. Colour differences were in the range of (deltaE* = 3.5-26.9), above the accepted threshold for perceptibility (deltaE* > 1) with a number above the threshold for what is considered to be clinically acceptable (deltaE* > 5.5). Improvements in colour match were seen for certain shade combinations of repairing composites, in contrast to when a single shade of composite was used.

Performance assessment of Vita Easy Shade spectrophotometer on colour measurement of aesthetic dental materials.

Four different shades were used to produce 20 samples of resin-based composite and 20 samples of porcelain to evaluate the performance ability of an intra oral test spectrophotometer compared to a reference spectrophotometer. The absolute colour coordinates CIELAB values measured with both spectrophotometers were significantly different (p < 0.001). However, a high correlation was found (p < 0.001) despite the low concordance noticed. The colour difference deltaE* values calculated between different shades also were significantly different between both spectrophotometers (p < 0.05). Therefore, the Easy Shade can be used in dental practice and dental research with some limitations.

An investigation into the effect of try-in pastes, uncured and cured resin cements on the overall color of ceramic veneer restorations: an in vitro study.

OBJECTIVES: The aim of this study was to assess how different shades of try-in pastes, uncured and cured resin cements influence the overall color of porcelain veneer restorations. METHODS: Porcelain veneers of shade Vita 1M1 VM7 and 1mm thick were applied to bovine teeth using three shades of resin cement and their try-in paste produced by three manufacturers. Analysis of variance was carried out on the color difference values (ΔE*) between the Aquagel and both the try-in paste and cured resins. An assessment of the clinical significance of ΔE* between the try-in paste and the cured resin and also between the uncured and cured resin was made. RESULTS: There were statistically significant differences in veneers' colors when using different shades of both Calibra and Nexus resin cements (p<0.05). Also, statistically significant differences were noticed when using different shades of both Rely-X and Nexus try-in pastes (p<0.05). Color differences produced between the try-in pastes and the corresponding shades of cured resin cements ranged from ΔE* 1.05 to 3.34. The color differences between uncured and cured resins of the same shade ranged from ΔE* 0.78 to 1.41. CONCLUSIONS: Different colored try-in pastes and resin cements produced color changes which are clinically useful in changing the color of veneer restorations and therefore aid color matching to adjacent dentition. Clinically significant differences were found between try-in pastes and the cured resin of the same shade, however, there were relatively small changes measured between uncured and cured resins. The color match achieved by the try-in paste has to be treated with caution and further assessment of the restoration made with the resin in place before curing is recommended.