The Healing of Exposed Implant Surfaces in A Maxillary Sinus Cavity / 대한치주과학회지

OBJECTIVE: The aim of this study was to investigate whether dental implant exposure to the maxillary sinus cavity increases the risk of maxillary sinus complications. STUDY DESIGN: An implant was placed bilaterally in the maxillary sinus of eight adult female mongrel dogs in a way that it penetrated the bone and mucous membrane of the maxillary sinus floor to the extent of 2 mm, 4 mm, or 8 mm. The implants were left in place for six months. RESULTS: Radiographic and histologic examinations did not show any signs of pathologic findings in the maxillary sinus of the eight dogs. CONCLUSION: This study indicates that implant protrusion into the maxillary sinus cavity is not related to the development of sinus complications.

Effect of the combined use of bone morphogenetic protein and platelet-derived growth factor on bone formation in nude mouse / 대한치주과학회지

Bone morphogenetic protein(BMP) and platelet-derived growth factor(PDGF) have been demonstrated tostimulate bone formation when applied locally in vivo. To explore whether or not the combined use of BMP and PDGF could have promotive effect and synergic interac- tion on bone formation in vivo, bone marrow mesenchymal stem cells were treated with BMP-2, PDGF-BB, or BMP-2 plus PDGF-BB, and then these cells were injected into the subcutaneous space on the dorsum of nude mice. The bone formation was evaluated after 12 weeks. Histomorphometric analysis demonstrated that the subcutaneous nodules formed in nude mice contained 25.3% newly formed bone in the BMP-2 treated cells, 14.4% newly formed bone in the PDGF-BB treated cells, and 8.9% newly formed bone in the BMP-2 plus PDGF-BB treated cells. The results showed that the combination of BMP-2 and PDGF-BB had neither a promotive effect nor synergic interact on bone formation in vivo.

A study of the effect of cultured bone marrow stromal cells on peripheral nerve regeneration

The role of cultured bone marrow stromal cells (BMSCs) in peripheral nerve regeneration was examined using an established rabbit peroneal nerve regeneration model. A 15-mm peroneal nerve defect was bridged with a vein filled with BMSCs (1 x 10(6)), which had been embedded in collagen gel. On the contralateral side, the defect was bridged with a vein filled with collagen gel alone. When the regenerated tissue was examined 4, 8 and 12 weeks after grafting, the number and diameter of the myelinated fibers in the side with the BMSCs were significantly higher than in the control side without the BMSCs. This demonstrates the potential of using cultured BMSCs in peripheral nerve regeneration.

Cyanoacrylate adhesive for closing of sinus membrane perforation during sinus lifts

AIM: To assess the efficacy of cyanoacrylate adhesive in the management of large perforations of the maxillary sinus membrane during sinus lifts. MATERIAL AND METHODS: Eight rabbits were used in the study. Sinus membrane perforation(about 1.5cm) was repaired with cyanoacrylate adnesive on one side of the maxillary sinus and the opppsite side was used as a control. Histological evaluation was performed 4 weeks after the operation. RESULTS: Histological studies showed normal healing of the sinus membrane across the site of previous perforation and no evidence of inflammation. CONCLUSION: Our results support the clinical use of cynoacrylate adhesive for repairing sinus membrane perforation.

Bone formation using injectable tissue-engineering materials

AIM: Several injectable materials have been used in the application of osteogenic bone substitute; however, nothing has won universal acceptance. This study was performed to investigate whether chitosan-alginate gel/MSCs/BMP-2 composites are potentially injectable materials for new bone formation. MATERIAL AND METHODS: The composites were injected into the subcutaneous space on the dorsum of the nude mouse to investigate whether new bone would be tissue engineered in the mouse. The composites were examined histologically over a 12-week period. RESULTS: The composites implanted in the mouse were able to tissue engineer new bone, and the newly formed bone consisted of trabecular bone and calcified bone matrix. CONCLUSIONS: The present study shows that chitosan-alginate gel/MSCs/BMP-2 composites have the potential to become real injectable materials for new bone formation.