Cellular reactions to polylactide-based sponge and collagen gel in subcutaneous tissue

Polylactide copolymer and collagen are now used as bio-absorbable scaffold materials for restoration of lost oral tissues. Polylactide caprolactone (PLCL) sponge and collagen gel were examined for their cellular reactions when implanted in 8-week-old Sprague-Dawley (SD) rats' subcutaneous tissues for up to 8 weeks. The PLCL sponges were slowly absorbed by a mild chronic inflammation process in which multinucleated giant cells covered and slowly captivated the sponge surfaces without thick encapsulation. On the other hand, collagen gel was surrounded by thick inflammatory reaction zones and infiltrated by acute inflammation cells including neutrophils, lymphocytes and macrophages, and disappeared more rapidly. Although the bio-absorption process differed, both materials, when combined, appear to be useful scaffold materials for tissue engineering therapy in future dental practice.