Deproteinized Bovine Bone Mineral Particles Research Articles

Morphological aspects and distribution of granules composed of deproteinized bovine bone or human dentin into a putty mixture: an in vitro study

ObjectiveThe main aim of this study was to evaluate the morphological aspects and distribution of granules composed of deproteinized bovine bone mineral (DBBM) and human dentin-derived bone graft (HDBG) into a putty consistency mixture.Materials and methodsDBBM or HDBG were mixed with an alginate-based hydrogel at two different granule/hydrogel ratio (1:1 and 1:3) and divided into four test groups while two control groups were composed of DBBM or HDBG free of hydrogel. Groups of specimens were cross-sectioned for morphological evaluation by scanning electron microscopy (SEM) at backscattered electrons mode. Details on the dimensions and pores’ size of DBBM and HDBG were evaluated after mixing different amounts of particles and alginate-based hydrogels.ResultsMicroscopic analyses revealed a size of DBBM granules ranging from 750 up to 1600 μm while HDBG particles showed particle size ranging from 375 up to 1500 μm. No statistical differences were identified regarding the size of granules (p > 0.5). The mean values of pores’ size of DBBM particles were noticed at around 400 μm while HDBG particles revealed micro-scale pores of around 1–3 μm promoted by the dentin tubules (p < 0.05). The lowest distance between particles was at 125 μm for HDBG and 250 μm for DBBM when the particle content was increased. On decreasing the particles’ content, the distance between particles was larger for DBBM (~ 1000 μm) and HDBG (~ 1100 μm). In fact, statistically significant differences were found when the content of granules increased (p < 0.05).ConclusionsThe increased content of bioactive ceramic granules in a putty consistency mixture with hydrogel decreased the space among granules that can promote a high ceramic density and stimulate the bone growth over the healing process. Macro-scale pores on bovine bone mineral granules stimulate the formation of blood vessels and cell migration while the micro-scale pores of dentin-derived granules are proper for the adsorption of proteins and growth of osteogenic cells on the bone healing process.Clinical significanceA high amount of bioactive ceramic granules should be considered when mixing with hydrogels as a putty material since that result in small spaces among granules maintaining the bone volume over the bone healing process. Deproteinized bovine bone mineral granules have macro-scale pores providing an enhanced angiogenesis while dentin-derived granules possess only micro-scale pores for the adsorption of proteins and proliferation of osteogenic cells on the bone healing process. Further studies should evaluate the combination of different bioactive ceramic materials for enhanced bone healing.

In Vivo Analyses of Osteogenic Activity and Bone Regeneration Capacity of Demineralized Freeze-Dried Bovine Bone Xenograft: A Potential Candidate for Alveolar Bone Fillers.

Background Deproteinized bovine bone mineral (DBBM) particle is the commonly used bone graft substitute in implant surgery which is mainly osteoconductive and has very slow degradation. Demineralized freeze-dried bovine bone xenograft (DFDBBX) particle is being developed as a novel xenogeneic bone filler. Objectives The study aimed to analyze osteogenic activity and bone-forming capacity of DFDBBX particles compared to DBBM particles in alveolar bone defects in rabbit mandibles models. Material and Methods. This study investigated bone defects whether filled with DBBM particles or DFDBBX particles or left unfilled in 30 rabbit mandibles. Specimens were processed for histology, immunohistochemistry, and micro-CT scanning. Statistical difference was set at a p value < 0.05. Results The quantitative assessment showed a significantly lower number of osteoclasts and a higher number of osteoblasts in the DFDBBX group compared to the DBBM group in 2 and 4 weeks (p < 0.05). Immunostaining analyses showed significantly higher expression of RUNX2, collagen type I, alkaline phosphatase, and osteocalcin in the DFDBBX group compared to the DBBM group in 2 and 4 weeks. Bone healing score in the DFDBBX group was comparable to the DBBM group. Micro-CT presented no significant difference in the volume percentage of the mineralized tissue in the DBBM and DFDBBX groups in spite of the different healing patterns in both groups. Conclusion DFDBBX particles induced higher osteoblastic activities than DBBM particles at the early stage of healing. Meanwhile, the capacity of bone formation in DFDBBX particles was comparable with DBBM particles at the later stage of healing. Considering the limitation of this study, the results presented DFDBBX particles as potential bone filler candidates.

Addition of autogenous bone chips to deproteinized bovine bone mineral does not have additional benefit in lateral ridge augmentation-A preclinical in vivo experimental study.

To compare the outcome after extensive lateral guided bone regeneration using deproteinized bovine bone mineral (DBBM) with or without autogenous bone chips in a canine model of chronic horizontal alveolar ridge defect. The second, third and fourth lower premolars of both sides were extracted, and the buccal bone walls were completely removed in five beagle dogs. After 4weeks, DBBM particles mixed with autogenous bone chips at a ratio of 1:1 were grafted at one side (DBBM/Auto group), while DBBM particles alone were grafted at the contralateral side (DBBM group). The graft materials on both sides were covered by a resorbable collagen membrane and fixation pins. Microcomputed tomographic volume and histomorphometric analyses were performed at 16weeks post-surgery. The ridges of both groups were recovered horizontally, but new bone formation beyond the original ridge contour at the defect site was not found. The DBBM group exhibited a larger total radiographic augmented volume and new bone volume compared with the DBBM/Auto group, but the differences were minimal (p>.05). Histologically, the regenerated area and new bone area were also slightly larger without any statistical significance in the DBBM group than in the DBBM/Auto group (p>.05). The addition of autogenous bone chips to DBBM for lateral ridge augmentation may confer no advantage over grafting DBBM alone with respect to both space maintenance and de novo bone formation in dogs.

Guided bone regeneration of chronic non-contained bone defects using a volume stable porous block TiO2 scaffold: An experimental in vivo study.

To evaluate new lateral bone formation and lateral volume augmentation by guided bone regeneration (GBR) in chronic non-contained bone defects with the use of a non-resorbable TiO2 -block. Three buccal bone defects were created in each hemimandible of eight beagle dogs and allowed to heal for 8weeks before treatment by GBR. Each hemimandible was randomly allocated to 4- or 12-week healing time after GBR, and three intervention groups were assigned by block randomization: TiO2 block: TiO2 -scaffold and a collagen membrane, DBBM particles: Deproteinized bovine bone mineral (DBBM) and a collagen membrane, Empty control: Collagen membrane only. Microcomputed tomography (microCT) was used to measure the lateral bone formation and width augmentation. Histological outcomes included descriptive analysis and histomorphometric measurements. MicroCT analysis demonstrated increasing new bone formation from 4 to 12weeks of healing. The greatest width of mineralized bone was seen in the empty controls, and the largest lateral volume augmentation was observed in the TiO2 block sites. The DBBM particles demonstrated more mineralized bone in the grafted area than the TiO2 blocks, but small amounts and less than the empty control sites. The TiO2 blocks rendered the largest lateral volume augmentation but also less new bone formation compared with the DBBM particles. The most new lateral bone formation outward from the bone defect margins was observed in the empty controls, indicating that the presence of either graft material leads to slow appositional bone growth.

Minocycline Hydrochloride as a Potential Adjuvant to Improve Osteoconductive and Osteoinductive Properties of Bone Substitutes in an Extra-Skeletal Bone Augmentation Model: Preliminary Observations in Rats

Abstract Objectives The present study was performed to determine if minocycline HCl could influence the behavior of deproteinized bovine bone mineral (DBBM) and bioactive glass (BG) particles when used as filler material for new bone generation in a guided bone augmentation model. Materials and Methods Two occlusive titanium caps were placed on the rat calvaria. One filled with BG particles, the second with DBBM particles, both previously mixed with blood (control). In minocycline HCl loaded groups (experimental), grafts were additionally placed into a minocycline solution. Samples were harvested after 4, 8, and 16 weeks. Half of the samples were embedded in methylmethacrylate for undecalcified histology and the other half was fixed, decalcified, and embedded in paraffin for classical histologic analysis. Results The control groups highlighted osteoconductive and osteoinductive responses associated to BG particles, as well as an osteoconductive reaction, in DBBM sections. The addition of minocycline HCl to BG particles had no measurable influence on the result. In minocycline HCl loaded DBBM sections; however, areas of spontaneous ossification could be observed after 8 and 16 weeks. Conclusion Our observations suggest that minocycline HCl may add some osteoinductive properties to DBBM within the limitations of this study design. Further investigations are needed to refine the present results.

Histologic Evaluation of Human Intrabony Periodontal Defects Treated with Deproteinized Bovine Bone Mineral in Combination with Orthodontic Tooth Movement: A Case Series.

The aim of this case series was the histologic evaluation of guided tissue regeneration utilizing deproteinized bovine bone mineral (DBBM) when regenerative surgery was combined with (test) or without (control) early orthodontic tooth movement. Core biopsy samples were harvested from previously defected sites after 9 months. The histologic section showed integration of DBBM particles in newly formed bone in the apical and middle thirds of the defect, while in the coronal part, graft materials were mainly embedded in connective tissues in the control patient. DBBM particles showed partial resorption with more de novo bone formation in test samples.

DBBM shows no signs of resorption under inflammatory conditions. An experimental study in the mouse calvaria.

ObjectivesDeproteinized bovine bone mineral (DBBM) is not resorbable. However, the behavior of DBBM under inflammatory conditions remains unclear. Aim of the study was therefore to evaluate the resorption of DBBM under local inflammatory conditions in vivo using the calvarial osteolysis model.MethodsIn thirty adult BALB/c mice, DBBM was implanted into the space between the elevated soft tissue and the calvarial bone. Inflammation was induced either by lipopolysaccharides (LPS) injection or by polyethylene particles (Ceridust) mixed with DBBM. Three modalities were randomly applied (n = 10 each): (a) DBBM alone (control), (b) DBBM + LPS, and (c) DBBM + polyethylene particles (Ceridust). Mice were euthanized on day fourteen, and each calvarium was subjected to histological and µCT analysis. Primary outcome was the size distribution of the DBBM particles. Secondary outcome was the surface erosion of the calvarial bone.ResultsHistological and µCT analysis revealed that the size distribution and the volume of DBBM particles in the augmented site were similar between DBBM alone and the combinations with LPS or polyethylene particles. Moreover, histological evaluation showed no signs of erosions of DBBM particles under inflammatory conditions. µCT analysis and histology further revealed that LPS and the polyethylene particles, but not the DBBM alone, caused severe erosions of the calvarial bone as indicated by large voids representing the massive compensatory new immature woven bone formation on the endosteal surface.ConclusionsLocal calvarial bone but not the DBBM particles undergo severe resorption and subsequent new bone formation under inflammatory conditions in a mouse model.

The influence of collagen membrane and autogenous bone chips on bone augmentation in the anterior maxilla: a preclinical study.

To evaluate the effect of a resorbable collagen membrane and autogenous bone chips combined with deproteinized bovine bone mineral (DBBM) on the healing of buccal dehiscence-type defects. The second incisors and the first premolars were extracted in the maxilla of eight mongrels. Reduced diameter, bone-level implants were placed 5weeks later. Standardized buccal dehiscence-type defects were created and grafted at implant surgery. According to an allocation algorithm, the graft composition of each of the four maxillary sites was DBBM+membrane (group D+M), autogenous bone chips+DBBM+membrane (group A+D+M), DBBM alone (group D) or autogenous bone chips+DBBM (group A+D). Four animals were sacrificed after 3weeks of healing and four animals after 12weeks. Histological and histomorphometric analyses were performed on oro-facial sections. The pattern of bone formation and resorption within the grafted area showed high variability among the same group and healing time. The histomorphometric analysis of the 3-week specimens showed a positive effect of autogenous bone chips on both implant osseointegration and bone formation into the grafted region (P<0.05). The presence of the collagen membrane correlated with greater bone formation around the DBBM particles and greater bone formation in the grafted region after 12weeks of healing (P<0.05). The oro-facial width of the augmented region at the level of the implant shoulder was significantly reduced in cases where damage of the protection splints occurred in the first week of healing (P<0.05). The addition of autogenous bone chips and the presence of the collagen membrane increased bone formation around DBBM particles. Wound protection from mechanical noxa during early healing may be critical for bone formation within the grafted area.

Sinus mucosa elevation using Bio-Oss® or Gingistat® collagen sponge: an experimental study in rabbits.

To describe the sequential healing in augmented sinus cavities with deproteinized bovine bone mineral (DBBM) granules or collagen sponges. Twenty albino New Zealand rabbits were included in the study. An incision was performed along the midline of the nasal dorsum, and the nasal bone was exposed. Circular bony windows with a diameter of 5mm were prepared bilaterally. After elevation of the mucosa, the two sites were randomly filled with either DBBM or a collagen sponge. Five animals each were randomly sacrificed after 7, 14, 21 and 40days, respectively. At both sides, new bone was found forming from the resident pristine bone. During the first stage of healing, DBBM granules were surrounded by a denser connective tissue that was attached to the biomaterial surface and that was progressively mineralized. At the collagen sponge side, the biomaterial was almost completely resorbed and the space was reduced by to two-thirds already after 21days. At both sides, after 40days, mineralized bone and marrow spaces were occupying large areas of the elevated space. New bone was found forming from the pristine bony walls of the sinus and extending toward the most peripheral regions in both sites. While DBBM particles yielded osteoconductivity and were able to preserve over time the space within the elevated mucosa, the collagen sponge failed the goal of maintaining the space.

Pre-coating deproteinized bovine bone mineral (DBBM) with bone-conditioned medium (BCM) improves osteoblast migration, adhesion, and differentiation in vitro.

Autogenous bone grafting has remained the gold standard for bone augmentation procedures with ability to release growth factors to the surrounding microenvironment. Recent investigations have characterized these specific growth factors released by autogenous bone chips with further isolation into a "bone-conditioned medium" (BCM). The aim of the present investigation was to utilize autologous growth factors from bone chips (BCM) in combination with deproteinized bovine bone mineral (DBBM) and investigate the ability for BCM to enhance osteoblast behavior. Mouse ST2 cells were seeded on (1) DBBM particles alone or (2) DBBM + BCM. Thereafter, samples were compared for cell recruitment, adhesion, proliferation, and real-time PCR for osteoblast differentiation markers including Runx2, collagen 1 alpha 2 (COL1A2), alkaline phosphatase (ALP), and osteocalcin (OCN). Alizarin red staining was used to assess mineralization. Coating BCM on DBBM particles improved cell migration of ST2 cells and significantly enhanced a 2-fold increase in cell adhesion. While no significant increase in cell proliferation was observed, BCM significantly increased mRNA levels of COL1A2, ALP, and OCN at 3days post seeding. Furthermore, a 3-fold increase in alizarin red staining was observed on DBBM particles pre-coated with BCM. Pre-coating DBBM with BCM enhanced the osteoconductive properties of DBBM by mediating osteoblast recruitment, attachment, and differentiation towards bone-forming osteoblasts. Future animal study is necessary to further characterize the added benefit of BCM as an autogenous growth factor source for combination therapies. The application of BCM in combination with biomaterials may serve as an autogenous growth factor source for bone regeneration.

Long-term stability of contour augmentation in the esthetic zone: histologic and histomorphometric evaluation of 12 human biopsies 14 to 80 months after augmentation.

Contour augmentation around early-placed implants (Type 2 placement) using autogenous bone chips combined with deproteinized bovine bone mineral (DBBM) and a collagen barrier membrane has been documented to predictably provide esthetically satisfactory clinical outcomes. In addition, recent data from cone beam computed tomography studies have shown the augmented volume to be stable long-term. However, no human histologic data are available to document the tissue reactions to this bone augmentation procedure. Over an 8-year period, 12 biopsies were harvested 14 to 80 months after implant placement with simultaneous contour augmentation in 10 patients. The biopsies were subjected to histologic and histomorphometric analysis. The biopsies consisted of 32.0% ± 9.6% DBBM particles and 40.6% ± 14.6% mature bone. 70.3% ± 14.5% of the DBBM particle surfaces were covered with bone. On the remaining surface, multinucleated giant cells with varying intensity of tartrate-resistant acid phosphatase staining were regularly present. No signs of inflammation were visible, and no tendency toward a decreasing volume fraction of DBBM over time was observed. The present study confirms previous findings that osseointegrated DBBM particles do not tend to undergo substitution over time. This low substitution rate may be the reason behind the clinically and radiographically documented long-term stability of contour augmentation using a combination of autogenous bone chips, DBBM particles, and a collagen membrane.

A digital evaluation of alveolar ridge preservation at implants placed immediately into extraction sockets: an experimental study in the dog

To compare with pristine sites bone resorption and soft tissue adaptation at implants placed immediately into extraction sockets (IPIES) in conjunction with deproteinized bovine bone mineral (DBBM) particles and a collagen membrane. The mesial root of the third premolar in the left side of the mandible was endodontically treated (Test). Flaps were elevated, the tooth hemi-sectioned, and the distal root removed to allow the immediate installation of an implant into the extraction socket in a lingual position. DBBM particles were placed into the defect and on the outer contour of the buccal bony ridge, concomitantly with the placement of a collagen membrane. A non-submerged healing was allowed. The premolar on the right side of the mandible was left in situ (control). Ground sections from the center of the implant as well as from the center of the distal root of the third premolar of the opposite side of the mandible were obtained. The histological image from the implant site was superimposed to that of the contralateral pristine distal alveolus, and dimensional variation evaluated for the hard tissue and the alveolar ridge. After 3 months of healing, both histological and photographic evaluation revealed a reduction of hard and soft tissue dimensions. The contour augmentation performed with DBBM particles and a collagen membrane at the buccal aspects of implants placed IPIES was not able to maintain the tissue volume.

Effect of pulverized natural bone mineral on regeneration of three-wall intrabony defects. A preclinical study

The objective of this study is to evaluate the effects of a paste-like bone substitute material with easy handling properties and improved mechanical stability on periodontal regeneration of intrabony defects in dogs. Mandibular and maxillary first and third premolars were extracted, and three-wall intrabony defects were created on second and fourth premolars. After a healing period of 3 months, acute type defects were filled with a paste-like formulation of deproteinized bovine bone mineral (DBBM) (particle size, 0.125-0.25 mm) in a collagenous carrier matrix (T1), pulverized DBBM (particle size, 0.125-0.25 mm) without the carrier (T2), or Bio-Oss® granules (particle size, 0.25-1.00 mm) as control (C). All defects were covered with a Bio-Gide® membrane. The dogs were sacrificed after 12 weeks, and the specimens were analyzed histologically and histometrically. Postoperative healing of all defects was uneventful, and no histological signs of inflammation were observed in the augmented and gingival regions. New cementum, new periodontal ligament, and new bone were observed in all three groups. The mean vertical bone gain was 3.26 mm (T1), 3.60 mm (T2), and 3.81 mm (C). That of new cementum was 2.25 mm (T1), 3.88 mm (T2), and 3.53 mm (C). The differences did not reach statistical significance. The DBBM particles were both incorporated in new bone and embedded in immature bone marrow. The results of this preclinical study showed that the 0.125-0.25-mm DBBM particles in a powder or paste formulation resulted in periodontal regeneration comparable to the commercially available DBBM. Osteoconductivity, in particular, was not affected by DBBM size or paste formulation. The improved handling properties of the paste-like bone substitute consisting of small DBBM particles embedded in a collagen-based carrier hold promise for clinical applications.

Ridge preservation at implants installed immediately after molar extraction. An experimental study in the dog

To evaluate the influence of deproteinized bovine bone mineral (DBBM), in conjunction with a collagen membrane, on bone resorption at implants installed in a lingual position immediately into extraction sockets with horizontal residual buccal defects >2.0mm. The pulp tissue of the mesial roots of (1) M(1) was removed in six Labrador dogs, and the root canals were filled with gutta-percha and cement. Flaps were elevated. The molars were hemi-sectioned and the distal roots removed. Implants were installed in a lingual position and with the shoulder flush with the buccal bony crest. After installation, defects of about 2.5 and 2.7mm in width resulted at the buccal aspects of the test and control sites, respectively. Only in the left site (test), deproteinized bovine bone mineral (DBBM) particles were placed into the defect concomitantly with the placement of a collagen membrane. On the control sites, no biomaterials were applied. A non-submerged healing was allowed. After 3months of healing, one control implant was not integrated and was excluded from the analysis, together with the contralateral test implant. All remaining implants were integrated into mature bone. The buccal alveolar bony crest was resorbed more at the test compared with the control sites, 2.2±0.9mm and 1.5±1.3mm, respectively. The vertical resorption of the lingual plate was 1.6±1.5mm and 1.5±1.1mm at the test and control sites, respectively. Only small residual DBBM particles were found at the test sites (1.4%). The use of DBBM particles to fill buccal defects of ≥2.5mm at implants installed immediately into alveolar extraction sockets did not preserve the buccal bony wall.

Healing outcomes at implants installed in sites augmented with particulate autologous bone and xenografts. An experimental study in dogs

To evaluate the integration of implants installed at the interface of pristine and grafted tissue augmented with particulate autologous bone or deproteinized bovine bone mineral (DBBM), concomitantly with a collagen membrane. In 6 Labrador dogs, the distal root of (3)P(3) and (4)P(4) was endodontically treated and hemi-sected, and the mesial roots extracted concomitantly with the extraction of (2)P(2). The buccal bony walls were removed, and two box-shaped defects, one larger and one smaller, were created. After 3 months, flaps were elevated, and the defects were filled with particulate autologous bone or DBBM in the right and left side of the mandible, respectively. Collagen membranes were used to cover the grafted areas. Three months later, flaps were elevated, and a customized device was used as surgical guide to prepare the recipient sites at the interface between grafts and pristine bone. One implant was installed in each of the four defects. After 3 months, biopsies were harvested and ground sections prepared for histological evaluation. The augmentation technique was effective at all sites and all the foreseen implants were installed. In the histological analysis, all implants were integrated in mature bone, at both the buccal and lingual aspects. The most coronal bone-to-implant contact and the top of the buccal bony crest were located at a similar distance between test and control implants. However, these distances were higher at the larger compared with the smaller defects. Especially in the large defect, residual particles of DBBM were found embedded into connective tissue and located outside the bony crest. Particulate autologous bone as well as DBBM particles used to augment horizontally the alveolar bony process allowed for the osseointegration of implants installed after 3 months of healing.

Alveolar bony crest preservation at implants installed immediately after tooth extraction: an experimental study in the dog

To evaluate the influence of deproteinized bovine bone mineral in conjunction with a collagen membrane, at implants installed into sockets in a lingual position immediately after tooth extraction, and presenting initial horizontal residual buccal defects <2 mm. The pulp tissue of the mesial roots of (4)P(4) was removed in six Labrador dogs, and the root canals were filled with gutta-percha and cement. Flaps were elevated, and the buccal and lingual alveolar bony plates were exposed. The premolars were hemi-sectioned, and the distal roots were removed. Implants were installed in a lingual position and with the margin flush with the buccal bony crest. After installation, defects resulted at about 1.7 mm in width at the buccal aspects, both at the test and control sites. Only in the left site (test), deproteinized bovine bone mineral (DBBM) particles were placed into the defect concomitantly with the placement of a collagen membrane. A non-submerged healing was allowed. After 3 months of healing, one implant was found not integrated and was excluded from the analysis together with the contralateral control implant. All remaining implants were integrated into mature bone. The bony crest was located at the same level of the implant shoulder, both at the test and control sites. At the buccal aspect, the most coronal bone-to-implant contact was located at a similar distance from the implant margin at the test (1.7 ± 1.0 mm) and control (1.6 ± 0.8 mm) sites, respectively. Only small residual DBBM particles were found at the test sites. The placement of an implant in a lingual position into a socket immediately after tooth extraction may favor a low exposure of the buccal implant surface. The use of DBBM particles, concomitantly with a collagen membrane, did not additionally improve the outcome obtained at the control sites.

Alveolar process preservation at implants installed immediately into extraction sockets using deproteinized bovine bone mineral – an experimental study in dogs

To evaluate the soft tissue and the dimensional changes of the alveolar bony crest at sites where deproteinized bovine bone mineral (DBBM) particles, concomitantly with the placement of a collagen membrane, were used at implants installed into sockets immediately after tooth extraction. The pulp tissue of the mesial roots of (3) P(3) was removed in six Labrador dogs, and the root canals were filled. Flaps were elevated bilaterally, the premolars hemi-sectioned, and the distal roots removed. Recipient sites were prepared in the distal alveolus, and implants were placed. At the test sites, DBBM particles were placed in the residual marginal defects concomitantly with the placement of a collagen membrane. No treatment augmentation was performed at the control sites. A non-submerged healing was allowed. Impressions were obtained at baseline and at the time of sacrifice performed 4 months after surgery. The cast models obtained were analyzed using an optical system to evaluate dimensional variations. Block sections of the implant sites were obtained for histological processing and soft tissue assessments. After 4 months of healing, no differences in soft tissue dimensions were found between the test and control sites based on the histological assessments. The location of the soft tissue at the buccal aspect was, however, more coronal at the test compared with the control sites (1.8 ± 0.8 and 0.9 ± 0.8 mm, respectively). At the three-dimensional evaluation, the margin of the soft tissues at the buccal aspect appeared to be located more apically and lingually. The vertical dislocation was 1 ± 0.6 and 2.7 ± 0.5 mm at the test and control sites, respectively. The area of the buccal shrinkage of the alveolar crest was significantly smaller at the test sites (5.9 ± 2.4 mm(2) ) compared with the control sites (11.5 ± 1.7 mm(2) ). The use of DBBM particles concomitantly with the application of a collagen membrane used at implants placed into sockets immediately after tooth extraction contributed to the preservation of the alveolar process.

Resorption of deproteinized bovine bone mineral in a porcine calvaria augmentation model

The original aim of the study was to determine the osteoconductive capacity of deproteinized bovine bone mineral (DBBM) of different particle sizes underneath acrylic hemispheres in vivo. However, the model failed and allowed us to report on the resorption of DBBM. Acrylic hemispheres were filled with and without a DBBM at a small particle size of 125-250 μm and at the regular particle size of 250-1000 μm. The hemispheres were positioned on the calvaria of eight minipigs. Histological and histomorphometric analysis was performed after 12 weeks. We found that the acrylic hemispheres were displaced and a dense fibrous capsule sequestered the augmented area. Histology showed severe resorption activity and the presence of multinucleated cells on the surface of DBBM particles in areas adjacent to the fibrous capsule. Histomorphometric analysis revealed that only less than half of the originally augmented area, which was approximately 30 mm(2) , remained after 12 weeks. The amount of residual DBBM (median 0.9 and 3.49 mm(2)) and bone (median 7.22 and 7.51 mm(2)) in the augmented area was similar in the small and the regular particle size group. The model represents a pathologic situation of excess resorption of DBBM and bone in an augmented area. The underlying cellular mechanisms remain to be uncovered.

Deproteinized bovine bone mineral in marginal defects at implants installed immediately into extraction sockets: an experimental study in dogs

To evaluate the influence of deproteinized bovine bone mineral (DBBM) particles concomitant with the placement of a collagen membrane on alveolar ridge preservation and on osseointegration of implants placed into alveolar sockets immediately after tooth extraction. The pulp tissue of the mesial roots of (3) P(3) was removed in six Labrador dogs and the root canals were filled. Flaps were elevated in the right side of the mandible, and the buccal and lingual alveolar bony plates were exposed. The third premolar was hemi-sectioned and the distal root was removed. A recipient site was prepared and an implant was placed lingually. After implant installation, defects of about 0.6 mm wide and 3.1 mm depth resulted at the buccal aspects of the implant, both at the test and at the control sites. The same surgical procedures and measurements were performed on the left side of the mandible. However, DBBM particles with a size of 0.25-1 mm were placed into the remaining defect concomitant with the placement of a collagen membrane. All implants were integrated into mature bone. No residual DBBM particles were detected at the test sites after 4 months of healing. Both the test and the control sites showed buccal alveolar bone resorption, 1.8 ± 1.1 and 2.1 ± 1 mm, respectively. The most coronal bone-to-implant contact at the buccal aspect was 2 ± 1.1 an 2.8 ± 1.3 mm, at the test and the control sites, respectively. This difference in the distance was statistically significant. The application of DBBM concomitant with a collagen membrane to fill the marginal defects around implants placed into the alveolus immediately after tooth extraction contributed to improved bone regeneration in the defects. However, with regard to buccal bony crest preservation, a limited contribution of DBBM particles was achieved.

Guided bone generation in a rabbit mandible model after periosteal expansion with an osmotic tissue expander

To evaluate the space-maintaining capacity of titanium mesh covered by a collagen membrane after soft tissue expansion on the lateral border of the mandible in rabbits, and to assess bone quantity and quality using autogenous particulate bone or bone-substitute (Bio-Oss(®) ), and if soft tissue ingrowth can be avoided by covering the mesh with a collagen membrane. In 11 rabbits, a self-inflatable soft tissue expander was placed under the lateral mandibular periosteum via an extra-oral approach. After 2 weeks, the expanders were removed and a particulated onlay bone graft and deproteinized bovine bone mineral (DBBM) (Bio-Oss(®) ) were placed in the expanded area and covered by a titanium mesh. The bone and DBBM were separated in two compartments under the mesh with a collagen membrane in between. The mesh was then covered with a collagen membrane. After 3 months, the animals were sacrificed and specimens were collected for histology. The osmotic soft tissue expander created a subperiosteal pocket and a ridge of new bone formed at the edges of the expanded periosteum in all sites. After the healing period of 3 months, no soft tissue dehiscence was recorded. The mean bone fill was 58.1±18% in the bone grafted area and 56.9±13.7% in the DBBM area. There was no significant difference between the autologous bone graft and the DDBM under the titanium mesh with regard to the total bone area or the mineralized bone area. Scanning electron microscopy showed that new bone was growing in direct contact with the DBBM particles and the titanium mesh. There is a soft tissue ingrowth even after soft tissue expansion and protection of the titanium mesh with a collagen membrane. This study confirms that an osmotic soft tissue expander creates a surplus of periosteum and soft tissue, and that new bone can subsequently be generated under a titanium mesh with the use of an autologous bone graft or DBBM.