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Aim: To examine in a discriminating capsule model whether denaturation of demineralized bone matrix (DBM) by heating may influence bone formation. Materials and methods: DBM was produced from the long bones of rats. Half the portion of DBM was denatured by heating in distilled water for 20 min at temperatures between 70°C and 90°C. Prior to the study, the destruction of the osteoinductive properties of the DBM was confirmed in three rats following intramuscular implantation. Thirty, 4-month-old, male albino rats of the Wistar strain were used in the study. Following surgical exposure of the mandibular ramus, a hemispherical Teflon capsule (internal diameter=5.0 mm) was placed, with its open part facing the lateral aspect of the ramus. On one side (test side), the capsule was loosely packed with denatured DBM, while on the contralateral side, serving as control, the capsule was loosely packed with the same amount of non-denatured DBM. After healing periods of 30, 60, and 120 days, groups of 10 animals were killed and 40–70 μm thick undecalcified sections of the capsules were produced. Three sections from each specimen, representing the mid-portion of the capsule, were subjected to histological analysis and computer-assisted planimetric measurements. Results: Increasing amounts of newly formed bone were observed in both test and control capsules during the experimental period. At 4 months, the new bone formed in the control capsules occupied 46.7% of the cross-sectional area of the capsules, while it was only 19.1% in the test capsules (P

Aim: To evaluate whether bone formation by guided tissue regeneration (GTR) and demineralized bone matrix (DBM) can be enhanced by the use of a cell-permeable Teflon barrier allowing the penetration of undifferentiated mesenchymal cells from the surrounding soft tissues. Material and methods: DBM was produced from the long bones of rats, and its bone-inductive properties were tested in three rats prior to the study by intramuscular implantation. Thirty, 4-month-old, male albino rats of the Wistar strain were used. Following surgical exposure of the mandibular ramus, a cell-permeable Teflon capsule, loosely packed with DBM, was placed with its opening facing the lateral surface of the ramus (test side). At the contralateral side, serving as control, a non-perforated (cell-occlusive) Teflon capsule, loosely packed with the same amount of DBM, was placed. After healing periods of 30, 60, and 120 days, groups of 10 animals were killed, and 40–70 μm thick undecalcified sections of the capsules were produced. Results: Computer-assisted planimetric measurements on the histological sections disclosed similar amounts of newly formed bone in both test and control capsules. After 4 months, the new bone in the control capsules occupied 45.0% of the cross-sectional area of the capsule, while it was 50.5% in the test capsules. This difference was not statistically significant (P

Bone morphogenetic proteins have proven to be effective bone inductors in animals and are therefore promising as inductors of bone formation in humans. In the present study we investigated the tissue formed after grafting osteogenic protein 1 on a collagen carrier (OP-1-device) in the human sinus floor elevation procedure. Three patients were grafted with OP-1 device. For comparison 3 groups of 3 patients were included in the study receiving respectively, autogenous bone, human freeze-dried demineralized bone matrix (DBM) or no graft. This last group had a sufficient alveolar bone height for dental implantation. Six months after grafting, at the time of implantation, biopsies were taken from the grafted area and/or the future dental positions. Undecalcified sections were used for histological and histomorphometrical analysis. All grafted sinuses showed an increased osteoid percentage when compared to non-grafted sinuses. Autogenous bone grafts all showed lamellar bone formation. In the DBM grafts mostly woven bone had been formed, predominantly by what appeared to be osteo-conduction. The OP-1 device gave rise to bone formation in 2 of the 3 patients. After 6 months implants could only be placed in 1 out of the 3 patients treated with OP-1 device. This patient showed mature lamellar bone formation, comparable to autogenous bone grafts. In the second patient all bone found was woven and the presence of a high osteoid percentage and large osteocyte lacunae indicated that this was recently-formed bone. Remnants of the collagen carrier were rare and new bone was never found against them, suggesting that this bone was formed by osteo-induction. In the third patient no new bone had been formed. The device had been encapsulated with fibrous tissue and inflammatory reaction was present. We conclude that in the human sinus floor elevation OP-1 has potential bone inductive capacity, but that results in the 3 patients tested with the current OP-1 device are inconsistent.

Objective The aim of this study was to estimate the effects of zirconia implants and recombinant human bone morphogenetic protein-2 (rhBMP-2) gel on the acceleration of local bone formation and osseointegration in the canine mandible. Materials and Methods Four groups of 48 implants with identical geometry were installed in the mandibles of beagle dogs: alumina-blasted zirconia implants applied with rhBMP-2, alumina-blasted zirconia implants applied with demineralized bone matrix (DBM), alumina-blasted zirconia implants, and resorbable blast media-treated titanium (Ti) implants. For the first two groups, zirconia implants were inserted after the surgical sites were filled with rhBMP-2 or DBM gel. For the other two groups, zirconia or Ti implants were installed with no adjunctive treatment. Fluorescent bone markers were administered to monitor bone remodeling at weeks 2, 4, and 5 postimplantation. After healing periods of 3 weeks and 6 weeks, the animals were sacrificed, and fluorescent microscopy, histology, and histomorphometric analyses were performed. Results Fluorescent microscopy showed that bone formation around the zirconia implants installed with rhBMP-2 gel was the most prominent at 2 weeks postimplantation, while the Ti implants acquired bone apposition mainly at week 5. No significant differences were found in bone area among the groups (P > 0.05). The zirconia implants showed similar bone-to-implant contact to the Ti implants. There were no significant differences in bone-to-implant contact between the zirconia implants with rhBMP-2 gel and those with DBM (P > 0.05). Conclusions The zirconia implants with alumina-blasted surfaces may achieve osseointegration in much the same manner as the well-established Ti implants. The area influenced by rhBMP-2 gel, including the alveolar crest, may cause active remodeling and early bone formation.

Objectives: Natural and synthetic graft materials are used routinely in sinus floor augmentations to help support implants in atrophic maxillary ridges. This clinical study was based on the hypothesis that the clinical effectiveness of demineralized freeze-dried bone allograft/demineralized bone matrix (DFDBA/DBM) in sinus lifts varies when used in combination bone graft substitute materials. To test this hypothesis, DFDBA was used together with one of three materials: in saline plus anorganic bone (DFDBA: Bio-Oss®); in hyaluronic acid (DFDBA: HY, 32 : 68, w/w; DBX®) alone; DBX® plus Bio-Oss®; and DBX® plus tricalcium phosphate granules (β-TCP). Material and methods: Thirty-two sinus lift procedures, eight per group, were performed on 26 patients. Before surgery and at 8 months post-surgery when implants were placed, ridge heights were visualized by computed tomography (CT) and measured by morphometric analysis. Cores of bone were removed by trephine at the sites of implant placement; these biopsies from the graft sites were used for histomorphometric analysis. Results: All 32 sinus lift elevations were successful when measured by CT, increasing from an average 2.84±0.2 mm before treatment to 15.2±0.6 mm after treatment. The percent of each biopsy that was occupied by new bone and incorporated bone graft materials varied with each treatment: DFDBA+Bio-Oss®, DBX®+Bio-Oss®, or DBX® alone was higher than that for DBX®+β-TCP by approximately 10%. When comparing only newly formed bone, DBX®+β-TCP treatment resulted in 50% less bone than the other three preparations. All grafted sites received implants as per the treatment plan for each patient. Conclusions: This study confirmed the hypothesis that new bone formation is dependent on the DFDBA formulation used and demonstrated that DBX®, alone or in combination with other materials, can be used successfully for sinus floor elevation.