Effect of C-factor and LED curing mode on microleakage achieved. For quantitative measurements, the gin, cavity shape and curing mode impacted dye average of the readings was taken, while for the leakage at the cementum/ dentin margin (P<.001). qualitative measurements, the worst degree of The mean depth of dye penetration for each dye penetration on both enamel and dentin mar- group is reported in Table 3. Group III (box-shaped gins were recorded. cavity with fast curing mode) was different than Statistical analysis was performed using SPSS the other three groups and showed the highest for Windows Version 16.0 (SPSS Inc., Chicago, IL). mean for the depth of dye penetration. There was For the quantitative data, multivariate ANOVA was no statistical difference between the other three performed with two independent variables (cavity groups. shape and curing mode), and with dye leakage at Table 4 shows the enamel dye penetration the enamel and at the cementum/dentine margins scores for the four groups. There was no sta- as dependent variables. Duncan’s multiple range tistical difference between the groups (P>.05). tests compared the groups at a significance level The predominant score for dye penetration in all of α<.05. For the qualitative data, the Kruskal- groups was 0 (no leakage). Wallis test and the Mann-Whitney U-tests were Table 5 shows the counts of dentin/cemen- used at a significance level of α<.05. Paired sam- tum dye penetration scores. Only group III (box- ple statistics was used to compare microleakage shaped cavity with fast curing mode) was signifi- at enamel and dentin margins. The significance cantly different than the other three groups (I and level was set at 0.05. III P<.001; II and III P<.01; III and IV P<.01). There was no statistical difference between the other rEsuLts groups (P>.05). The results of the multivariate ANOVA on the Paired sample statistics was used to com- effects of cavity shape and curing mode on dye pare microleakage at enamel and dentin margins. penetration at the enamel and cementum/dentine There was no statistical difference in microleak- margins are presented in Table 2. At the enamel age between enamel and dentin margins for all margin, there were no observed effects of cavity of the groups except for group III, where den- shape and curing mode on dye penetration (P>.05). tinal leakage was greater than enamel leakage On the other hand, at the cementum/dentine mar- (P<.000). Table 1. Distribution of the groups used in the study. Group I II III IV N 20 20 20 20 Cavity shape V V Box Box Curing mode Fast Soft-start Fast Soft-start Radiation protocol 15 seconds at 1100 mW/cm2 10 seconds from 0 to 1100 mW/cm2 + 10 seconds at 1100 mW/cm2 15 seconds at 1100 mW/cm2 10 seconds from 0 to 1100 mW/cm2 + 10 seconds at 1100 mW/cm2 Radiation exposure 16.5 J/cm2 16.5 J/cm2 16.5 J/cm2 16.5 J/cm2 Table 2. Results for the multivariate ANOVA on the effect of cavity shape and curing mode on the dye penetration at the enamel and cementum/dentine. Multivariate test (Wilks’ Lambda) F df Enamel Margin 0.313 76 Cementum/Dentin Margin 6.745 76 Enamel Margin X Cementum/Dentin Margin 3.24 150 Note: *** P=.001; ****P=.0001 P-value ns **** *** Table 3. Means and standard deviations (mm) of depth of dye penetration (measured quantitatively) at the occlusal and gingival margins. Group I II III IV 404 * Means for homogeneous subsets are displaced. European Journal of Dentistry Enamel margin 0.265 (0.524)a 0.415 (0.798)a 0.465 (0.743)a 0.420 (0.688)a Cementum/Dentin margin 0.485 (0.731)a 0.670 (0.850)a 1.400 (0.538)b 0.650 (0.633)a