The effect of collagen and bioaggregate scaffold on perforated dental pulp

Background: In cases of dental pulp exposures, dental pulp tissue must be covered with biocompatible materials to maintain viability of tooth. Dental tissue engineering has concentrated on materials and techniques which will reconstitute lost tooth structures. In this study we used sponge scaffold, which was made from collagen and BioAggregate materials on perforated sheep teeth and we investigated its effect on the reconstituted dental tissue between four and eight weeks with histological examination. Materials and Methods: In our study, four sheep were used as experimental animals. Collagen and BioAggregate mixed and created a porous scaffold with lyophilization process in the laboratory. After creating the sponge scaffold, we characterized the scaffold through the mercury porosimetry test and SEM imaging in order to determine pore size and density. Afterwards, the scaffolds were placed on expose mandibular incisor teeth pulp of sheeps. 4 and 8 weeks later, sheeps were decapitated and teeth were extracted. The formation of new tissue at pulp exposure area was observed on histological sections of teeth through light microscope. The histological sections were monitorized and the amount of dentin formation was measured by using CellSens Standard Software program. The dentin bridge formed was compared statistically by Mann-Whitney U test week by week. Results: Mercury porosimetry test and SEM imaging showed that scaffolds were suitable for cell attachment and cell organization to reconstitute new dental tissue. At the end of the 4th week, it was observed that formation of the repaired tissue in the character of osteodentin was completely covered the area of perforation. Moreover, at the end of the 8th week, the repaired tissue formation was more compact and in tubular formation compared to the repaired tissue in the 4th week. In some histological sections in the 8th week, it was observed that the repaired tissue formation developed towards outside of perforation site into the scaffold. The repaired tissue was not greater in the 8th week than the 4th week (p >0.05). Conclusions: Biocompatible sponge scaffolds may be used at dental pulp exposures to maintain viability of dental pulp tissue and reconstitute lost tooth structures. Key Words: Scaffold, Collagen, BioAggregate, Direct pulp capping