histological and histomorphometric analysis of animal experimental dehiscence defect treated with three bio absorbable gtr collagen membrane

background: guided tissue regeneration (gtr) allows mesenchymal cells to repopulate the defects. however, there is limited information regarding the effi cacy of different membranes. the present study was designed to histologically and histomorphometrically compare three collagen membranes in regenerative treatment of dehiscence defects in dogs. materials and methods: this 8 weeks experimental animal study comprised 4 healthy dogs. 5 x 5 mm periodontal dehiscences were created in each side of the mandible (4 dehiscences in each side of dogs’ mandible). in each side, one dehiscence defect was left uncovered as a control site and three other sites were randomly covered with different collagen membranes (biogide (bg), biomend (bm), and cytoplast (cyt)). histomorphometric and histologic analysis were conducted at 4 and 8 weeks. data were analyzed using anova, mann-withney, kruskal-wallis and fisher ’s exact tests (α= 0.05). results: according to histomorphometric analysis there was a signifi cant difference between treatment and control groups regarding the bone formation and the distance between the reference point and apical end of junctional epithelium (dje) ( p < 0.05). at 4 weeks, the maximum amount of bone thickness and height was observed in bg and cyt respectively, and this maximum rate was seen with the use of bg at 8 weeks. it was shown that dje reached its highest rate in bm and cyt at 4 and 8 weeks, respectively. organized pdl was formed in treatment groups. conclusion: the membrane-treated groups had a statistically signifi cant increase in bone formation and connective tissue attachment compared to control groups. however, there are some differences among experimental groups, which should be considered in gtr treatments. key words: bone regeneration, collagen membrane, dehicens defect