RESUMEN
Following extraction of teeth the alveolar ridge resorbs and may result in inadequate bone volume for dental implant placement. The aim of this study was to make a histologic and morphometric analysis of the effect of using Bio-oss [a bovine derived xenograft] and Cerasorb [a beta tricalcium phosphate synthetic material] in preventing or reducing the alveolar bone resorption following tooth extraction in comparison with empty sockets as untreated control in a dog model. In this interventional animal study, 5 healthy adult dogs were used. The 2[nd] and 3[rd] mandibular premolars were extracted after reflecting a surgical flap. Following random allocation, the available sockets either served as the untreated control [n=13] or received either Bio-oss [n=10] or Cerasorb [n=10] as test groups. An alginate impression was taken before the application of materials to fabricate a stone cast to serve as an index to make morphometric measurements. The healing events were uncomplicated and six months after the surgical procedures, the dogs were sacrificed and after removing the soft tissues, another impression was taken from the mandibular hard tissues and the tissue blocks were prepared for histologic examination. Morphometric maesurments aimed to measure the changes in vertical dimentions of the buccal and lingual bony plates as well as the horizontal reduction of the ridge at the crest. The data were analyzed by ANOVA and Kruskal-Wallis test. The histologic evaluation included the examination of the quality of the harvested hone as well as the inspection for the presence of remnants of unresorbed biomaterials. The mean changes of buccal and lingual crests and mean ridge reduction were not significantly different between control and cases groups. Histologic examination revealed that in all three groups, the cortical bony plates were thinner and of lower density at the buccal side compared to the lingual side. No trace of inflammatory cell infiltration was observed in any groups. In general, the histologic appearance of the 3 types of specimens resembled to normal lamellar bone. The results of this study showed that the vertical and horizontal resorbion of alveolar ridge following the extraction were minimal at three groups even at the untreated control sites