Yasar, Akgunlu Cl 1 and Cl 3 cortical morphology (P=0.008); but homogeneous, that is the sizes of the porosities there was no statistically significant difference within the cortices are similar to each other. between Fractal Dimension of radiographs which were classified as having Cl 2 and Cl 3 cortical dIscuIon morphology (P=1.000). For Lacunarity, Kruskal Panoramic mandibular index (PMI),27 Wallis test was used and it was found that there mandibular cortical width (CW),28 antegonial was also statistically significant difference AGI),29 gonial index (GI)30 and mandibular cortical between different MCI groups for Lacunarity index (MCI)12 are panoramic based indices which (P=0.001). The mean differences were significant are developed to discriminate osteoporotic at the 0.05 level (P=0.05) (Table 5). For paired patients from non-osteoporotic ones. Some of comparisons between the groups, Mann Whitney the researchers reported that, these indices U statistics with Bonferroni correction was used. were effective in discriminating osteoporotic It was found that there was statistically significant patients10,29,30 but there are other studies in which difference between Cl 1 and Cl 2 (P=0.003) and Cl some of these indices were reported to be not 1 and Cl 3 (P=0.001) but there weren’t statistically useful in identifying osteoporotic patients.13,17,31 significant difference between Cl 2 and Cl 3 Some measurements and calculations are (P=0.758) as in FD (Table 5). necessary in PMI, CW, AGI and GI. Among these According to the results of this study, the indices, MCI is relatively simple because no mandibular cortex having Cl 1 cortical morphology measurements or calculations are required but it is less complex and more heterogeneous than depends on visual assessments. Its repeatability Cl 2 and Cl 3. That means, there is wider range has been evaluated and especially inter-observer of sizes of structures within the cortices which agreement is reported to be poor in some of the are classified as Cl 1 and contrary to this, the studies.19 However, Bollen et al,11 Klemetti et cortices which are classified as having Cl 3 al,12 Taguchi et al,13 have reported satisfactory cortical morphology are more complex and levels of inter and intra-observer agreement. Table 3. Analysis of variance for fractal dimension. Between Groups Within Groups Total 0.148 * The mean difference is significant at the 0.05 level. Table 4. Paired comparisons with Bonferroni correction. MCI Observations Fractal Dimension Cl1-Cl2 Cl1-Cl3 Cl2-Cl3 Sum Of Squares 0.048 0.101 Mean Difference -0.0639 -0.0548 0.0090 df 2 49 51 SE 0.0140 0.0173 0.0175 Mean Square F Sig 0.024 0.002 11.583 0.000 95% Confidence Interval Lower Bound Upper Bound Table 5. Kruskal Wallis test for Lacunarity and paired comparisons for Lacunarity with Mann Whitney U Test with Bonferroni correction. Kruskal Wallis Test Chi-Square df 14.236 2 Lacunarity Analysis Mann Whitney U Wilcoxon W Z -2.947 Asymp. Sig. 0.001 Asymp. Sig. (2-tailed) 0.003 *: The mean difference is significant at the 0.05 level. Grouping Variable: MCI October 2008 - Vol.2 Sig.* 0.000 0.008 1.000 Cl1 - Cl2 103.000 313.000 287 European Journal of Dentistry -0.0985 -0.0976 -0.0345 Cl1 - Cl3 26.000 81.000 -3.415 0.001 -0.0292 -0.0120 0.0525 Cl2 - Cl3 93.000 148.000 -0.348 0.758