Comparison of Evaluation-Methods of Cement-Joint Homogeneity of Luting-Materials for Posts

Aim: Aim of this study was the comparative evaluation of two methods used to examine the cement joint homogeneity of adhesive luting materials for cementing endodontic posts. Material und method: There were 4 groups with 5 glass fiber posts each. Posts were inserted in artificial root-canals under standardised conditions. Following experimental conditions were examined: group I = Unicem and cement application with a new fill-in aid °¥elongation-tip'; group II = Unicem, group III = Panavia F and group IV = Variolink II, whereas in groups II-IV the posts were cemented conventionally. All specimen were sectioned perpendicular to the long axis of the post at three levels (cervical, middle, apical) and examined and photographed in a SEM (n=60). All inhomogeneities of the cement joint were (I) measured by means of a SEM programm (I=measure-method) and (II) estimated using a graphic program where SEM micrographs were distinguised in 72 equal segments of a circle to calculate a percent value of inhomogenities of the 360¢X circumference (II=circle-segment method). The statistical analysis were performed by using the Pearson-Correlation test, the test of Kruskal-Wallis, and Mann-Whitney as post hoc test (ƒÑ=0.05). Results: The values of inhomogeneities within the cement-joint for the cervikal, middle, apikal analysis level (median measure-method / median circle-segment method) [%] were for group I=1.4/2.1; 2.2/4.2; 1.9/2.1; group II=21.0/20.1; 24.8/23.6; 27.0/24.3; group III=1.5/1.7; 5.5/6.3; 19.4/20.8, and for group IV=18.1/16.7; 16.1/15.3; 27.2/25.7. Both methods correlated very good (0.994), whereas the 1 means a 100 % correlation. The results of the evaluation methods differ only 1.2 % for the median values. No significant differences were found (ƒÑ=0,709). Conclusion: Both evaluation methods of the present study are appropriate equal to quantify cement-joint homogenity of cross sections of adhesively cemented endodontic posts.