This study was performed to evaluate whether there is the difference of graft height changes in radiographic evaluation in single implants and multiple implants after maxillary sinus floor augmentation with an auto-xenograft mixture.

The study group comprised 29 patients (16 men, 13 women; mean age, 56.5±12.4 years; range, 27 to 87 years) treated at the implant clinic of the Ewha Womans University Mokdong Hospital. They were treated with the sinus floor augmentation of lateral window technique and simultaneous placement of dental implants. Their implants have been evaluated for 42.4±10.5 months. To evaluate the height of grafted material, the real implant length was compared with that of panoramic radiography evaluated by a digital caliper (PACS program), and then the real height of grafted material was assumed. SPSS 19.0 was used in statistical analysis. Wilcoxon singed rank test was utilized for P value and Mann-Whitney for statistical significance in the changes of grafted height between single implants and multiple implants. The level of statistical significance was defined as P<0.001.

The evaluated graft height in single implants' group decreased to 0.60±0.54 mm at the time of delivery (after 7.5 months, P=0.001), in multi-unit implants' group to 0.96±0.84 mm (after 6.5 months, P<0.001). The evaluated graft height in single implants' group decreased to 1.11±0.75 mm at the last follow-up (after 43.5 months, P=0.001), in multi-unit implants' group to 1.52±0.99 mm (after 41.8 months, P<0.001). Mann-Whitney test was used for the difference between single implants and multi-unit implants. There was no difference in two groups at the time of delivery and the last follow-up (P>0.001).

There was no statistical significance of radiographic graft height after maxillary sinus floor augmentation between single implants and multiple implants.

This study was performed to evaluate the effect of autogenous iliac particulated marrow cancellous bone graft on osseointegration of implants in the dog tibia which has a loose bone marrow.

Three mongrel dogs, weighing about15kg or more, and RBM(resorbable blasted media) AVANA® implants(Osstem Inc., Korea) were used in this study. In the control groups, 2 implants sites were prepared conventionally with drills in the left metaphysic of tibia and 2 implants were placed in each dog under general anesthesia. In the experimental groups, 2 implant sites were prepared with drills. and the particulated marrow cancellous bone, which was obtained from the right ilium,was packed into both prepared sites with osteotomes in the right metaphysic of tib-ia in each dog. Two implants were placed. A total of 12 implants were placed in 3 dogs. The animals were sacrificed at 8 weeks after implant placement. The specimens were taken and embedded into the resin. H & E stain was done. The undecalcified specimens were prepared for histological examination and histomorphometric analysis of bone-implant contact ratios. The Mann-Whitney test was used to compare both groups.Values of p<0.01were considered statistically significant.

In the cross-sectional radiographs of the control group no trabecular bone was observed in the marrow space and the implant was surrounded with radiolucent marrow space. In the experimental group Some radioaque trabecular bone was observed in the marrow space of tibia and some of the trabecula was contacted with implant surface. Histologically,in the control group few trabecular bone was observed in marrow space and there was poor osseointegration in the marrow. In the experimental group most marrow space was filled with the trabecular boneand the implant surface was contacted with trabecular bone. In histomorphomeric analysis the bone-implant contact ratio of the experimental group(75.6%) was significantly higher than that of the control group(27.1%, p<0.01).

The autogeneous bone graft into the loose bone marrow can be an option to improve the bone density and to get better osseointegration of dental implants.