Most resin cements include shades typically with three distinctive levels of opacity: Opaque shade (high opacity for enhanced masking power), Regular shades (medium opacity), and Clear/Translucent shade (low opacity for maximized clarity). Objective: to characterize the opacities of the Opaque, Regular, and Clear shades of five commercial resin cements: Nexus2 (NEX, Kerr), Calibra (CAL, Dentsply), Choice (CHO, Bisco), RelyX-ARC (RLX, 3M), and Variolink II (VAR, Vivadent). Methods: Specimens (n=3) were pre
pared using a ring mold (Ф/h: 20/1mm) and the cured specimens were conditioned in de-ionized water at 37oC for 24 hours before testing. The opacity (0% being total clear and 100% being total opaque) was measured using a Spectrophotometer (Model SP60, X-Rite Inc.). For the Regular shade, the universal, A3, yellow, or medium shade was chosen. Results: ANOVA analysis revealed that, for the Clear shade, NEX had significantly lower (p < 0.05) opacity than other cements tested and RLX had significantly higher (p < 0.05) opacity than other cements tested. For the Regular shade, NEX had significantly lower (p < 0.05) opacity than other cements tested and CHO had significantly higher (p<0.05) opacity than other cements tested. For the Opaque shade, the opacities of NEX and VAR were not statistically different (p < 0.05) from each other, but significantly higher (p < 0.05) than other cements.|
NEX |
CAL |
CHO |
RLX |
VAR |
|
|
Clear |
46.0+0.5%a* |
63.6+0.3%d |
50.9+0.3%b |
65.8+0.7%e |
55.9+0.3%c |
|
Regular |
58.0+0.3%a |
68.1+0.6%c |
79.8+0.8%d |
68.6+0.1%c |
60.8+0.2%b |
|
Opaque |
99.4+0.1%b |
95.4+0.2%a |
94.8+0.3%a |
NA |
99.6+0.2%b |
*Means with the same letter within the same row are not statistically different at p < 0.05.
Conclusions: For the Clear and Regular shades, NEX exhibited the lowest opacity (or highest clarity) among all cements tested in this study. For the Opaque shade, NEX and VAR had opacities close to 100% (total opaqueness), demonstrating extremely high masking power.