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.