Periodontal repair in dogs:: Analysis of histometric assessments in the supraalveolar periodontal defect model

Background: Traditionally, the mean value from histometric assessments of several histologic sections from the same site has been, used for the histometric characterization of the site. The histometric analysis of the supraalveolar periodontal defect model uses observations from buccal and lingual sites in three step-serial sections representing the central aspect of the mesial and distal root-for the third and fourth mandibular premolar teeth. The objectives of this study were to investigate the correlations and determine whether there are significant differences in the measurement values of various histometric parameters between the three step-serial sections and to test the hypothesis that, in this animal model, histometric assessments using the most central section of each root are comparable to the mathematical means of corresponding assessments of the site using the three step-serial sections. Methods: Histometric analysis using light microscopy, an attached digital camera system, and a personal computer-based image analysis system including a custom program for the supraalveolar periodontal defect model was performed on histologic sections acquired from one jaw quadrant in each of 12 dogs. The animals had received a protocol including placement of a coral biomaterial and guided tissue regeneration (GTR) membranes, and were evaluated following a 4-week healing interval. Twelve parameters were assessed using three central step-serial sections from each root. For each parameter, pair-wise comparisons were performed using the mixed models analysis of variance, and the correlations between measurements were assessed by the intraclass correlation coefficient (ICC). Results: For all parameters assessed, there were no significant differences (P >0.05) among the three sections. The differences between the central section and the means of the three step-serial sections were small and not statistically significant. Parameters that could be assessed on most or all specimens, such as defect height and area, membrane height, and bone regeneration area, showed high correlations among the three step-serial sections (intraclass coefficient [ICC] similar to 0.91 to 0.98), and between each of the three sections and the mean for the three step-serial sections (ICC greater than or equal to0.95). The most central section had somewhat higher correlation with the mean than measurements made on the lateral sections. Conclusion: The results suggest that using the supraalveolar periodontal defect model representative histometric data can be obtained evaluating only the central section from each defect site.