Effects of various implant materials on regeneration of calvarial defects in rats.

The purpose of the present study was to determine the best implant material, the best conditions to substitute absorbable membrane for non-absorbable membrane, and the factors influencing guided regeneration of critical size defects using experimental rats. An 8-mm circular transosseous calvarial bony defect was made and implant materials, such as demineralized freeze-dried bone (DFDB), absorbable membrane (BioMesh; Samyang Co., Seoul Korea), non-absorbable membrane (Millipore filter; Micro Filtration System, MA, USA) or a combination of these materials, was placed on the defect. As for the results of sequential time-based guided bone regeneration, histological, histochemical, immunohistochemical and histomorphometric aspects were observed, and a statistical comparative analysis was performed, with control group of a soft tissue flap. Bone formation was significantly enhanced when DFDB was retained within the defect with a protective absorbable membrane. Inframembranous DFDB-filling was required to prevent membrane collapse and to preserve spaces for bone regeneration. The absorbable membrane which was recommended to overcome the disadvantages of the non-absorbable membrane should remain intact for more than 5 weeks in order for it to be effective. The macrophages recruited by grafts were involved partly in decreasing bone regeneration via the sequential events of releasing fibronectin, and in chemotactic effect of the fibronectin to fibroblasts and collagen lay-down. Thus, the activity of new bone formation was dependent upon the physical barrier effect of the membrane, such as the preserving ability to secure spaces and the suppression ability of early infiltration of collagen and epithelium, inducible ability of inflammation by the implant material, and potential in guiding bone regeneration of the grafts.

Grafting of large defects of the jaws with a particulate dentin-plaster of paris combination.

OBJECTIVE: The purpose of this report is to show the usefulness and discuss the effects of a particulate dentin and plaster of paris combination as a bone graft material in jaw defects. STUDY DESIGN: This was a retrospective evaluation of 10 patients with jaw defects who underwent grafting with a combination of particulate dentin and plaster of paris. The material was used when the defects were more than 20 mm in diameter. The ratio was 2:1 by weight. Patients were examined for any evidence of infection and recurrence during the follow-up periods. RESULTS: During a mean follow-up of 52.2 months (range, 50 to 57 months), patients had minor immediate postoperative complications. These complications were swelling and perforation; they were treated without problems through use of incision and drainage, antibiotic treatment, and buccal flap. CONCLUSIONS: On the basis of the results that we obtained radiographically and clinically, it may be concluded that the particulate dentin plaster mixture is a useful and readily available material for bone substitute.

Use of the tongue flap for intraoral reconstruction: a report of 16 cases.

PURPOSE: This article reports the authors' experience with the use of the tongue flap for intraoral soft tissue reconstruction. PATIENTS AND METHODS: From May 1992 to December 1996, 16 patients were treated with a tongue flap for reconstruction of a variety of intraoral soft tissue defects. Ages ranged from 16 to 65 years with a mean of 39.6 years. RESULTS: The procedure was successful in 15 patients. There were six complications: one total necrosis, four partial necroses, and one infection. Partial necrosis and infection were well controlled by conservative treatment. CONCLUSION: Use of the tongue flap is a versatile method for reconstruction of a variety of intraoral soft tissue defects.

Tissue response to titanium plates: a transmitted electron microscopic study.

PURPOSE: This study investigated the tissue response associated with titanium plates. MATERIALS AND METHODS: Titanium miniplates were used to stabilize fractured bones and a bone graft in 14 patients. At the time of plate removal, the osteosynthesis sites were carefully examined macroscopically. After the removal of the plates, biopsies of the 14 soft tissues and two bony sites surrounding the plates were performed for light microscopic and transmitted electron microscopic examination. RESULTS: Macroscopically, visible pigmentation was found in the soft tissue in 14% of the patients, but none in the bone. With light microscopy, pigmentation was found in the soft tissue of 10 of 14 sites and in one of two bony sites. Transmitted electron microscopy showed suspected titanium particles in the connective tissue of all specimens. The small particles were located between the collagen fibers. In some specimens, small particles were noted within the fibroblasts and macrophages. There were degenerative changes around the minute particles in the bone matrix. CONCLUSION: Local macroscopic or microscopic tissue destruction was observed in hard and soft tissue near the titanium miniplates. If the plates remain for a long time, there is a possibility that they may cause further tissue damage. These findings suggest that the titanium miniplates should be removed routinely after bone healing.