IADR Abstract Archives
Technical Considerations for de Novo PDL Regeneration in Mini-swine Model
Objectives: The aim of this study was to determine de novo orthotopic periodontal ligament (PDL) regeneration for avulsed teeth in a mini-swine model.
Methods: Ectopic PDL regeneration using mouse model was first performed. Human or mini-swine roots deprived of cellular contents were treated with 1.5% NaOCl followed by 17% EDTA and normal saline. Human (h) or swine (s) PDL stem cells (PDLSCs) at passages 2-3 were grown to over-confluent cell sheet in UpCell temperature sensitive dishes and three layers of cell sheets were attached onto a biodegradable PGA membrane which was then wrapped onto the root (human or swine respectively) with cells facing the root surface and tightened with resorbable sutures. The PGA/cells/root construct was transplanted into the subQ space of SCID mice. For orthotopic PDL regeneration in mini-swine, an alveolar bone socket was created by dental implant drills in the edentulous region of mandible and the PGA/sPDLSCs/root construct was inserted into the socket and the wound closed. The animals were sacrificed ~3 months later, and the teeth were decalcified and stained for histological analysis.
Results: In the ectopic regeneration mouse model, we observed a layer of PDL-like tissue around the root, however, minimal to no new cementum regeneration on the root surface as detected except cementicle-like mineral granules were seen in certain areas in the PDL-like tissue around root surface. In the orthotopic regeneration mini-swine model, the implanted roots tended to be extruded out of the mandible and lost, or resorbed in the bone over time based on radiographic observations. Histologically there were soft connective fibrous tissues surrounding the root with inflammatory infiltrates and root surface resorption. We also attempted to use ortho-wire to hold the implanted tooth with the adjacent tooth, however, the bone resorption occurred around the implanted root.
Conclusions: The protocols for orthotopic de novo PDL regeneration in mini-swine models require further optimization.
Methods: Ectopic PDL regeneration using mouse model was first performed. Human or mini-swine roots deprived of cellular contents were treated with 1.5% NaOCl followed by 17% EDTA and normal saline. Human (h) or swine (s) PDL stem cells (PDLSCs) at passages 2-3 were grown to over-confluent cell sheet in UpCell temperature sensitive dishes and three layers of cell sheets were attached onto a biodegradable PGA membrane which was then wrapped onto the root (human or swine respectively) with cells facing the root surface and tightened with resorbable sutures. The PGA/cells/root construct was transplanted into the subQ space of SCID mice. For orthotopic PDL regeneration in mini-swine, an alveolar bone socket was created by dental implant drills in the edentulous region of mandible and the PGA/sPDLSCs/root construct was inserted into the socket and the wound closed. The animals were sacrificed ~3 months later, and the teeth were decalcified and stained for histological analysis.
Results: In the ectopic regeneration mouse model, we observed a layer of PDL-like tissue around the root, however, minimal to no new cementum regeneration on the root surface as detected except cementicle-like mineral granules were seen in certain areas in the PDL-like tissue around root surface. In the orthotopic regeneration mini-swine model, the implanted roots tended to be extruded out of the mandible and lost, or resorbed in the bone over time based on radiographic observations. Histologically there were soft connective fibrous tissues surrounding the root with inflammatory infiltrates and root surface resorption. We also attempted to use ortho-wire to hold the implanted tooth with the adjacent tooth, however, the bone resorption occurred around the implanted root.
Conclusions: The protocols for orthotopic de novo PDL regeneration in mini-swine models require further optimization.