ABSTRACT
Background: This study compared the effect of various grafting materials on the area and volume of minerals attached to dental implants. Materials and Methods: In this animal study, 13 dogs were divided into three groups according to the time of sacrificing (2 months, 4 months, or 6 months). The implants were placed in oversized osteotomies, and the residual defects were filled with autograft, bovine bone graft (Cerabone), or a synthetic substitute (Osteon II). At the designated intervals, the dogs were sacrificed and the segmented implants underwent micro-computed tomography analysis. The bone-implant area (BIA) and bone-implant volume (BIV) of bone and graft material were calculated in the region of interest around the implant. The data were analyzed by two-way analysis of variance (ANOVA) at P < 0.05. Results: There was no significant difference in BIA and BIV between the healing intervals for any of the grafting materials (P > 0.05). ANOVA exhibited comparable BIA and BIV between the grafting materials at 2 and 4 months after surgery (P > 0.05), although a significant difference was observed after 6 months (P < 0.05). Pairwise comparisons revealed that BIA was significantly greater in the autograft-stabilized than the synthetic-grafted sites (P = 0.035). The samples augmented with autograft also showed significantly higher BIV than those treated by the xenogenic (P = 0.017) or synthetic (P = 0.002) particles. Conclusion: All graft materials showed comparable performance in providing mineral support for implants up to 4 months after surgery. At the long-term (6-month) interval, autogenous bone demonstrated significant superiority over xenogenic and synthetic substitutes concerning the bone area and volume around the implant.
ABSTRACT
OBJECTIVES: Autologous bone transplantation known as the "gold standard" to reconstruction of osseous defects has known disadvantages. This study was designed to explore the effects of hydroxy-apatite/tricalcium-phosphate (HA/TCP) and platelet-rich plasma (PRP) on the osteogenesis ability of human adipose-derived mesenchymal stem cells (hAdMSCs) in vitro and in vivo. MATERIALS AND METHODS: hAdMSCs were incubated with HA/TCP granules and/or PRP in vitro and then, cell proliferation and differentiation was assessed by MTT assay, AZR S staining and SEM examination. In vivo, four cylindrical defects were drilled in the mandibular bones of 5 mongrel dogs and divided randomly into the following groups: I-autologous crushed bone, II- no filling material, III- HA/TCP and PRP, IV- PRP-enriched hAdMSCs seeded on HA/TCP granules. Inserted hAdMSCs were labeled to trace their contribution to bone tissue regeneration. Finally, cell tracing and tissue regeneration were evaluated by immunohistochemistry and histomorphometry methods, respectively. RESULTS: In vitro, co-incubation with HA/TCP granules significantly reduced proliferation and osteogenic differentiation ability of hAdMSCs; while PRP application promoted these capacities (P<0.05). In vivo, PRP-enriched hAdMSCs seeded on HA/TCP granules induced considerable bone formation in osseous defects (P<0.05). It was obviously shown that hAdMSCs were incorporated into the newly-formed bone. CONCLUSION: Based on this study, application of stem cells could offer a helpful therapeutic tool in bone tissue regeneration. Although inserted hAdMSCs were identifiable throughout the newly-formed bone tissue, their few number could be an indicator of indirect role of hAdMSCs in tissue regeneration.
ABSTRACT
BACKGROUND: Due to the known disadvantages of autologous bone grafting, tissue engineering approaches have become an attractive method for ridge augmentation in dentistry. To the best of our knowledge, this is the first study conducted to evaluate the potential therapeutic capacity of PRP-assisted hADSCs seeded on HA/TCP granules on regenerative healing response of canine alveolar surgical bone defects. This could offer a great advantage to alternative approaches of bone tissue healing-induced therapies at clinically chair-side procedures. METHODS: Cylindrical through-and-through defects were drilled in the mandibular plate of 5 mongrel dogs and filled randomly as following: I- autologous crushed mandibular bone, II- no filling material, III- HA/TCP granules in combination with PRP, and IV- PRP-enriched hADSCs seeded on HA/TCP granules. After the completion of an 8-week period of healing, radiographic, histological and histomorphometrical analysis of osteocyte number, newly-formed vessels and marrow spaces were used for evaluation and comparison of the mentioned groups. Furthermore, the buccal side of mandibular alveolar bone of every individual animal was drilled as normal control samples (n=5). RESULTS: Our results revealed that hADSCs subcultured on HA/TCP granules in combination with PRP significantly promoted bone tissue regeneration as compared with those defects treated only with PRP and HA/TCP granules (P<0.05). CONCLUSION: In conclusion, our results indicated that application of PRP-assisted hADSCs could induce bone tissue regeneration in canine alveolar bone defects and thus, present a helpful alternative in bone tissue regeneration.
ABSTRACT
BACKGROUND: Facial artery myomucosal flap pedicled solely on skeletonized facial artery has been reported in the literature. Venous drainage of this modified flap is doubtful so an animal study was designed to verify the survival of this flap. MATERIAL: Three healthy adult male mongrel dogs with weight between 20 to 30 kg were enrolled in this study. Split mouth technique was used in this experiment. Flap paddle was designed over the facial artery and vein. Facial vein was ligated and divided. Flap was returned to the original site and sutured (experimental group). In the other side, flap was harvested but returned to the original position without disturbing the vascular pedicle (positive control). RESULTS: All buccal mucosa island flaps with preserved facial artery and vein were survived, whereas all the flaps with the occlusion of facial vein undergo necrosis. CONCLUSION: Island FAMM flap, pedicled only on skeletonized facial artery, is not biologically accepted for clinical usage.
