Periodontal Tissue Engineering by Cementoblastic Cell Therapy

Objective: Predictable regeneration of periodontal structures following periodontal disease is a major goal of therapy. We evaluated the ability of cementoblasts and dental follicle cells delivered via PLGA polymer sponges to promote periodontal regeneration ex vivo using a rodent periodontal fenestration model. Methods: The buccal aspect of the distal root of the first mandibular molar was denuded of its PDL, cementum and superficial dentin through a bony window created bilaterally in 8 athymic rats. A total of 15 teeth were divided into three groups: carrier alone, carrier + follicle cells and carrier + cementoblasts (n=5 per group). One million cells per carrier were delivered to the defects via biodegradable PLGA polymers and mandibulae were retrieved 21 days post-surgery for histological and histomorphometrical evaluation. Results: Histological analysis of samples retrieved from defects treated with carrier alone or carrier + follicle cells indicated PLGA particles and fibrous tissue within the healing area, with minimal evidence of osteogenesis. In contrast, in samples retrieved from teeth treated with cementoblasts, mineralized tissues were noted at the healing site with extension towards the PDL region and laterally beyond the envelop of buccal plate of bone. No new cementum or functional PDL were observed histologically in any of the groups at 21 days. The total area of newly formed mineralized tissue was 0.74±0.15 mm² (carrier alone), 0.53±0.27 mm² (carrier + follicle cells) and 7.30±2.54 mm² (carrier + cementoblasts), respectively. The defect fill was 56±16% (carrier alone), 35±11% (follicle cells) and 79±3% (cementoblasts), respectively. Conclusion: These findings suggest that cementoblasts have a marked ability to induce mineralization in periodontal wounds when delivered via polymer sponges compared to dental follicle cells or polymer carrier alone. These results support a role for cementoblast-like cells for use in designing periodontal regenerative therapies. Supported by NIH/NIDCR grants DE13047 and DE13397.