• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.6
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• pp.469-477
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• 2009

Purpose: This study was performed to evaluate the effect of various graft materials used with a titanium cap on the ability of new bone formation in the rabbit calvarium. Materials and Methods: A total of 32 sites of artificial bony defects were prepared on the calvaria of sixteen rabbits by using a trephine bur 8 mm in diameter. Each rabbit had two defect sites. 0.2 mm deep grooves were formed on the calvaria of sixteen rabbits by using a trephine bur 8 mm in diameter for the fixation of a titanium cap. The treatments were performed respectively as follows: without any graft for the control group (n=8), autogenous iliac bone graft for experimental group 1 (n=8), alloplastic bone graft ($SynthoGraft^{(R)}$, USA) for experimental group 2 (n=8), and xenogenic bone graft ($NuOss^{(R)}$, USA) for experimental group 3 (n=8). After the treatments, a titanium cap (8 mm in diameter, 4 mm high, and 0.2 mm thick) was fixed into the groove. At the third and sixth postoperative weeks, rabbits in each group were sacrificed for histological analysis. Results: 1. In gross examination, the surgical sites showed no signs of inflammation or wound dehiscence, and semicircular-shaped bone remodeling was shown both in the experimental and control groups. 2. In histological analysis, the control group at the third week showed bone remodeling along the inner surface of the cap and at the contact region of the calvarium without any specific infiltration of inflammation tissue. Also, there was no soft tissue infiltration. Bone remodeling was observed around the grafted bone and along the inner surface of the titanium cap in experimental group 1, 2, and 3. 3. Histologically, all groups at the sixth week showed the increased area of bone remodeling and maturation compared to those at the third week. In experimental group 2, the grafted bone was partially absorbed by multi nucleated giant cells and new bone was formed by osteoblasts. In group 3, however, resorption of the grafted bone was not observed. 4. Autogenous bone at the third and sixth week showed the most powerful ability of new bone formation. The size of newly formed bone was in decreasing order by autogenous, alloplastic, and heterogenous bone graft. There was no statistically significant difference among autogenous, alloplastic, and heterogenous bones(p>0.05). Summary: This result suggests that autogenous bone is the best choice for new bone formation, but when autogenous bone graft is in limited availability, alloplastic and xenogenic bone graft also can be an alternative bone graft material to use with a suitably guided membrane.

• Journal of Environmental Impact Assessment
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• v.32 no.6
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• pp.389-406
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• 2023

The research area, located in the northern coastal region of South Korea's West Sea, involves three bird habitats. Among these are two newly established habitats in Songdo International Business District, created by filling and developing tidal flats that were previously utilized as stopover sites for migratory birds. One of these areas showed decrease (Residual tidal flats, site.1) while the other showed increase (Artificial lake, site.2) in bird influx. The third habitat (Namdong reservoir, site.3) is a pre-existing stable habitat which has been maintained as a stable habitat. This study conducts an assessment of habitats based on avian population clusters and environmental surveys and proposes habitat management measures. A survey of bird populations and habitat environments was conducted for a total of 39 occasions from January to December 2022. The observed bird species totaled 14 families and 48 species with 20,760 individuals. Compared to the existing habitats, the newly established habitats showed relatively lower influx of bird species and individuals. During the habitat assessment, the newly established habitats were rated as I to II grade, while the existing habitat was rated as relatively high III grade on the grading assessment of the tidal flat. An analysis of habitat types revealed that the existing habitat, in which diverse strategies for habitat type diversity and mitigating anthropogenic interference were demonstrated, attracted a diverse range of bird species. Through this research, it was deduced that the diversity of habitat types plays a significant role in attracting various bird species. Upon evaluation of habitat types concerning the habitat characteristics of the bird species selected for habitat management, as habitat management measures, it is deemed that the creation of shielded green areas (referred to as 'buffer green') to minimize interference from the surroundings, the establishment of reed fields (site.1, 2) positively correlated with reservoirs, and the improvement of sandbanks (site.1) positively associated with tidal flats, the two relations which we drew from correlation analysis between occurrence species and habitat types, would contribute to the future restoration and maintenance of stable habitats. The results of this study can be applied not only to the study area but also to other development zones, such as coastal reclamation sites, which share similar geographical and environmental characteristics, including arrival sites for migratory birds.