Treatment of alveolar cleft with distraction osteogenesis using anchorage with a tooth-microimplant joint in a dog model.

Our aim was to investigate the efficacy of correction of an alveolar cleft with distraction osteogenesis using anchorage with a tooth-microimplant joint in a canine model, which was established in 12 adult mongrel dogs that were subsequently randomised into two groups (n=6 in each). The first group comprised dogs that had osteogenesis using anchorage with a tooth (tooth group), while in the second, anchorage with tooth-microimplant joint (microimplant group) was used. All animals were killed one month after completion of distraction. Samples were collected for gross observation and histological examination. There was a significant difference in the degree of movement of the anchorage teeth in the transport discs between the 2 groups (p<0.01). There was less prominent inclination and shift of the natural teeth in the transport disc and less bony resorption around the root in the microimplant group than in the tooth group. These changes were less remarkable in the microimplant group. Treatment of alveolar cleft by distraction osteogenesis using anchorage with a tooth-microimplant joint is practical, and yields better results.

[Maxillary sinus augmentation with simultaneous implantation using guided bone regeneration].

OBJECTIVE: To investigate the effect of new bone formation in sinus augmentation with guided bone regeneration (GBR) using collagen membranes. METHODS: The first maxillary molars of 18 adult female Beagle dogs were extracted and the sinus floors of both sides were lifted with simultaneous implantation. A combination of autografts and Bio-Oss in a 2:1 ratio was placed in the space under the membrane. On the experimental side in each dog, the collagen membrane was folded at the lateral osteotomy window, the apex of the implants and a certain part of palatal bone. On the contralateral control side, the collagen membrane only covered the osteotomy window. Six animals were sacrificed at 4, 12, and 24 weeks respectively after surgery. Gross observation, biomechanical testing and histological examinations were performed. RESULTS: The translocation of grafted materials and bone absorption were found on the top of implants in the control side, and the grafted materials kept original shape at the experimental side at 4th week. The granule of Bio-oss absorbed obviously at 12th and 24th week. The pull-out force increased with time. At 24th week, the force of pull out was 558.1 ± 37.4 N at the study side, and 471.4 ± 31.5 N at the control side. There was a significant difference in the pull-out force was noted between the two groups (P < 0.01). Histological examination showed new bone formation on the sinus floor, and the grafted materials gradually reduced with time CONCLUSIONS: GBR with the enfolded-coverage of the membrane can effectively decrease absorption of the grafted materialon the apical surface of implants and stimulate new bone formation in the sinus augmentation.