Small versus large particles of demineralized freeze-dried bone allografts in human intrabony periodontal defects

Autologous Tooth Granulometry and Specific Surface Area with Three Grinding Methods: An In Vitro Study

A postextraction socket becomes a clinical challenge due to the fact that a series of changes associated with bone remodelling and resorption of the socket that occur after extraction, which limits the aesthetic and functional prognosis of implant-supported rehabilitations. It has been studied that the use of the autologous tooth-derived graft (ATDG) has regenerative properties and could therefore be useful for solving this type of problem. There is no consensus in the scientific literature on a standardized protocol for the use of the autologous tooth. Therefore, the aim of the present study was to evaluate the most relevant parameters to achieve the best properties of ground ATDG using three methods, namely Gouge forceps, electric grinder, and manual, that made up the study group (SG) and compared with the control group (CG) consisting of Bio-Oss®. The sample obtained by the electric grinder had the highest value of specific surface area (2.4025 ± 0.0218 m2/g), while the particle size as average diameter (751.9 µm) was the lowest and most homogeneous of the three groups. Therefore, the electric grinder allowed for obtaining ATDG with more regenerative properties due to its specific surface-area value and particle size in accordance with the xenograft with the greatest bibliographical support (Bio-Oss®). The higher specific surface increases the reaction with the physiological media, producing faster biological mechanisms.

Optimized bone grafting

Bone grafting is routinely performed in periodontology and oral surgery to fill bone voids. While autogenous bone is considered the gold standard because of its regenerative properties, allografts and xenografts have more commonly been utilized owing to their availability as well as their differential regenerative/biomechanical properties. In particular, xenografts are sintered at high temperatures, which allows for their slower degradation and resorption rates and/or nonresorbable features. As a result, clinicians have combined xenografts with other classes of bone grafts (most notably allografts and autografts in various ratios) for procedures requiring better long-term stability, such as contour grafting, sinus elevation procedures, and vertical bone augmentations. This review addresses the regenerative properties of each class of bone grafts and then highlights the importance of understanding each of their biomechanical and regenerative properties for clinical applications, including extraction site management, contour augmentation, sinus grafting, and horizontal and vertical augmentation procedures. Thereafter, an introduction toward the novel production of nonresorbable bone allografts (NRBAs) via high-temperature sintering is presented. These NRBAs not only pose the advantage of being more biocompatible than xenografts owing to their origin (human vs. animal bone) but also display nonresorbable properties similar to those of xenografts. Thus, while packaging allografts with xenografts in premixtures specific to various clinical indications has never been permitted owing to cross-species contamination and FDA/CE requirements, the discovery and production of NRBAs allows premixing with standard allografts in various ratios without regulatory restrictions. Therefore, premixtures of allografts with NRBAs can be produced in various ratios for specific indications (e.g., a 1:1 ratio similar to an allograft/xenograft mixture for sinus grafting) without the need for purchasing separate classes of bone grafts. This optimized form of bone grafting could theoretically provide clinicians more precise ratios without the need to purchase separate bone grafts. This review highlights the future potential for simplified and optimized bone grafting in periodontology and implant dentistry.

The impact of deproteinized bovine bone particle size on histological and clinical bone healing outcomes in the augmented sinus: A randomized controlled clinical trial

OBJECTIVE

The effect of different deproteinized bovine bone mineral (DBBM) particle sizes on bone healing in maxillary sinus floor augmentation remains unclear. This study compared the newly formed tissue and angiogenesis-related bone healing after sinus floor augmentation using large or small DBBM particles.

MATERIALS AND METHODS

Overall 32 patients were randomly divided into two groups using either large (1-2 mm) or small (0.25-1 mm) DBBM particles for sinus floor augmentation. After 6 months, the mineralized tissue volume was calculated using micro-computed tomography (micro-CT) analysis. The newly formed tissue composition was histomorphometrically analyzed. Angiogenesis was also examined by means of vascular endothelial growth factor (VEGF) expression. Implant failure and marginal bone loss were measured at a 1-year follow-up. Statistical analysis was performed using independent samples t-test.

RESULTS

Micro-CT analysis demonstrated that grafting with large particles resulted in higher bone volume (6.99 ± 2.72 mm³ , p = 0.002) and Bone Volume/Tissue Volume (0.25 ± 0.1, p = 0.03) compared with small particles (3.76 ± 1.83 mm³ and 0.14 ± 0.13, respectively). Small particles showed higher non-mineralized tissue volume (26.31 mm³ ) compared with large particle group (17.4 ± 5.34 mm³ ) with p = 0.001. The histological data revealed significantly higher area of newly formed bone (32.15% ± 14.04% for the large particle and 15.99% ± 14.12% for the small particle groups, p = 0.004). Likewise, non-mineralized tissue was significantly greater in the small particle group (66.48% ± 20.97%) compared with the large particle group (44.36%, p = 0.016). Moreover, use of large particles resulted in a significantly higher VEGF staining intensity score and VEFG positive cells. No implant failure was recorded in both groups, while no difference was found in terms of marginal bone loss at the 1-year follow-up.

CONCLUSIONS

Sinus floor augmentation using large DBBM particles resulted in more angiogenesis expression, higher bone volume, and new bone formation at 6 months after sinus augmentation. However, clinical outcomes with regards to implant placement were similar in both groups.

Dentascan an excellent tool for assessment of variations in the management of periodontal defects

Background

The purpose of the present study was to envisage the effectiveness of demineralized freeze-dried bone allograft (DFDBA) and bovine bone graft (BBG) for promoting defect fill in periodontal intrabony defects using dentascan.

Materials and Methods

A total of 13 subjects (15 intrabony defects) aged between 24 and 56 years affected by moderate to severe periodontitis were randomly divided into Control (CG) and Test groups (TG1 and TG2). In CG only debridement, TG1 debridement plus DFDBA, and TG2 debridement plus BBG were performed. The clinical parameters probing pocket depth (PPD), clinical attachment level (CAL) was used. The radiological analysis was done by dentascan, which is a single-slice spiral computed tomographic scanner. Six months after, regenerative treatment clinical measurements were recorded. The bone fill was assessed using Dentascan as previously mentioned.

Results

PPD reduction and CAL gain were significant in all the groups after 6 months whereas, on intergroup comparisons, insignificant finding was observed both at baseline and after 6 months. Coronoapical bone status decreased significantly in all groups, buccolingual measurements decreased significantly in TG1 and TG2, but no such trend was seen in CG. Significant reduction in mesiodistal bone status was noticed only in TG1 whereas insignificant on intergroup comparisons.

Conclusion

Dentascan-based analysis attested that DFDBA was superior to BBG.

Histologic and histomorphometric evaluation of bone regeneration using nanocrystalline hydroxyapatite and human freeze-dried bone graft : An experimental study in rabbit

PURPOSE

Bone regeneration is an important concern in periodontal treatment and implant dentistry. Different biomaterials and surgical techniques have been used for this purpose. The aim of the present study was to compare the effect of nanocrystalline hydroxyapatite and human freeze-dried bone graft (FDBG) in regeneration of rabbit calvarium bony defects by histologic and histomorphometric evaluation.

METHODS

In this experimental study, three similar defects, measuring 8 mm in diameter, were created in the calvaria of 16 white New Zealand rabbits. Two defects were filled with FDBG and nanocrystalline hydroxyapatite silica gel, while the other one remained unfilled to be considered as control. All the defects were covered with collagen membranes. During the healing period, two animals perished; so 14 rabbits were divided into two groups: half of them were euthanized after 6 weeks of healing and the other half after 12 weeks. The specimens were subjected to histologic and histomorphometric examinations for assessment of the following variables: percentage of bone formation and residual graft material, inflammation scores, patterns of bone formation and type of newly formed bone.

RESULTS

The percentages of new bone formation after 6 weeks were 14.22 ± 7.85, 21.57 ± 6.91, and 20.54 ± 10.07% in FDBG, NanoBone, and control defects. These values were 27.54 ± 20.19, 23.86 ± 6.27, and 26.48 ± 14.18% in 12-week specimens, respectively. No significant differences were found in the amount of bone formation between the groups. With regard to inflammation, the control and NanoBone groups showed significantly less inflammation compared to FDBG at the 6-week healing phase (P = 0.04); this difference was not significant in the 12-week specimens.

CONCLUSIONS

Based on the results of this experimental study, both NanoBone and FDBG exhibited a similar effect on bone formation.

Bone Grafts in Periodontal Therapy

This article is limited to a review of bone replacement graft materials used in periodontal therapy. The source, mode of bone regeneration and the respective advantages and disadvantages of autogenous, allogenic, xenogenic and alloplastic materials are discussed.

Cranial bone regeneration according to different particle sizes and densities of demineralized dentin matrix in the rabbit model

Background

The objective of this study was to place bone graft materials in cranial defects in a rabbit model and compare their bone regenerating ability according to the size and density of demineralized dentin matrix (DDM).

Methods

We selected nine healthy male rabbits that were raised under the same conditions and that weighed about 3 kg. Two circular defects 8 mm in diameter were created in each side of the cranium. The defects were grafted with DDM using four different particle sizes and densities: 0.1 mL of 0.25- to 1.0-mm particles (group 1); 0.2 mL of 0.25- to 1.0-mm particles (group 2); 0.1 mL of 1.0- to 2.0-mm particles (group 3); and 0.2 mL of 1.0- to 2.0-mm particles (group 4). After 2, 4, and 8 weeks, the rabbits were sacrificed, and bone samples were evaluated by means of histologic, histomorphometric, and quantitative RT-PCR analysis.

Results

In group 1, osteoblast activity and bone formation were greater than in the other three groups on histological examination. In groups 2, 3, and 4, dense connective tissue was seen around original bone even after 8 weeks. Histomorphometric analysis of representative sections in group 1 showed a higher rate of new bone formation, but the difference from the other groups was not statistically significant. RT-PCR analysis indicated a correlation between bone formation and protein (osteonectin and osteopontin) expression.

Conclusions

DDM with a space between particles of 200 μm was effective in bone formation, suggesting that materials with a small particle size could reasonably be used for bone grafting.

Bone Regeneration Using Dentin Matrix Depends on the Degree of Demineralization and Particle Size

Objectives

This study aimed to examine the influence of particle size and extent of demineralization of dentin matrix on bone regeneration.

Materials and Methods

Extracted human teeth were pulverized and divided into 3 groups according to particle size; 200, 500, and 1000 μm. Each group was divided into 3 groups depending on the extent of demineralization; undemineralized dentin (UDD), partially demineralized dentin matrix (PDDM), and completely demineralized dentin matrix (CDDM). The dentin sample was implanted into rat calvarial bone defects. After 4 and 8 weeks, the bone regeneration was evaluated with micro-CT images, histomorphometric and immunohistochemical analyses. Osteoblasts were cultured on UDD and DDM to evaluate the cell attachment using electron microscope.

Results

Micro-CT images and histological observation revealed that CDDM had largely resorbed but UDD had not, and both of them induced little bone formation, whereas all particle sizes of PDDM induced more new bone, especially the 1000 μm. Electron microscopic observation showed osteoblasts attached to DDM but not to UDD.

Conclusions

PDDM with larger particle size induced prominent bone regeneration, probably because PDDM possessed a suitable surface for cell attachment. There might be an exquisite balance between its resorption and bone formation on it. PDDM could be considered as a potential bone substitute.

Bone repair is influenced by different particle sizes of anorganic bovine bone matrix: a histologic and radiographic study in vivo

PURPOSE

The aim of this study was to analyze histologically and radiographically the influence of particle size of anorganic bovine bone matrix (ABBM) on bone repair.

MATERIALS AND METHODS

Four calvarial defects of 8 mm each were prepared in 18 adult New Zealand rabbits. The defects were then filled with either particulate autogenous bone (control group) or ABBM of large, medium, and small size granules. The animals were sacrificed at 15, 30, and 60 days after surgery. The samples were radiographically examined before being submitted to histological processing.

RESULTS

Autogenous bone showed a slight radiopacity at the beginning, which was increased at the final period, being very similar to the adjacent bone tissue. The large and medium size ABBM particles maintained the same radiographic behavior, showing a radiolucent area in the central portion of the defect at 60 days. ABBM of small size granules showed a slight radiolucity at the initial period, which was increased at the subsequent periods. More intense bone formation occurred in the control group (autogenous bone). All 3 particle sizes of the biomaterial resulted in inflammatory infiltration at 15 and 30 days. ABBM of small size granules lead to a greater amount of osteoid tissue, and the particles were almost totally reabsorbed within 60 days of implantation.

CONCLUSIONS

Autogenous bone graft lead to the best result in terms of bone defect repair; ABBM of large and medium size granules are not totally reabsorbed at the observed period; ABBM of small size granules was more intensively reabsorbed and led to a greater osteoid tissue formation when compared to the medium and large ABBM granules.

A comparative evaluation of freeze dried bone allograft and decalcified freeze dried bone allograft in the treatment of intrabony defects: A clinical and radiographic study

BACKGROUND

Ideal graft material for regenerative procedures is autogenous bone graft but the major disadvantage with this graft is the need for a secondary surgical site to procure donor material and the frequent lack of intraoral donor site to obtain sufficient quantities of autogenous bone for multiple or deep osseous defects. Hence, to overcome these disadvantages, bone allografts were developed as an alternative source of graft material.

MATERIALS AND METHODS

In 10 patients with chronic periodontitis, 20 bilateral infrabony defects were treated with freeze dried bone allograft (FDBA-Group A) and decalcified freeze dried bone allograft (DFDBA-Group B). Clinical and radiographic parameters were assessed preoperatively and at 3 months and 6 months postoperatively. Data thus obtained was subjected to statistical analysis.

RESULTS

Significant improvement in the reduction in probing depth and relative attachment level (RAL) from the baseline to 3 months to baseline to 6 months in group A and group B, which was statistically significant but no statistically significant reduction was seen between 3 months and 6 months. On inter-group comparison, no significant differences were observed at all-time points. In adjunct to the probing depth and RAL, the radiographic area of the defect showed a similar trend in intra-group comparison and no significant difference was seen on inter-group comparison at all-time points.

CONCLUSIONS

Within the limitations of the current study, it can be concluded that DFDBA did not show any improvement in the clinical and radiographic parameters in the treatment of the intrabony defects as compared to FDBA.

Comparison of nanocrystalline hydroxyapatite and synthetic resorbable hydroxyapatite graft in the treatment of intrabony defects: A clinical and radiographic study

Background:

The aim of this study is to compare, clinically and radiographically, the effectiveness of nanocrystalline hydroxyapatite (NHA) and synthetic resorbable hydroxyapatite (HA) in the treatment of intrabony defects.

Materials and Methods:

Ten subjects with bilateral defects, with probing depth (PD) 6-9 mm and radiographic evidence of an intraosseous component ≥4 mm participated in the present study. Subjects were allocated randomly to treatment with NHA (test group) or HA (control group). At baseline, 3 and 6 months after surgery, the following clinical parameters were recorded: Plaque index, gingival index, PD, relative attachment level (RAL), and radiographic reduction in intrabony defect.

Results:

At 6 months following therapy, the test group showed a reduction in mean PD from 6.4 ± 0.843 to 3.3 ± 0.8232 mm and a change in mean RAL from 12.9 ± 1.197 to 10.1 ± 0.7378 mm, whereas in the control group the mean PD decreased from 7.65 ± 1.8566 to 3.9 ± 1.1005 mm, and mean RAL decreased from 13.9 ± 0.9944 to 10.7 ± 0.6749 mm. On comparison of the mean difference in probing depth between the two groups after the unpaired t-test was applied at baseline, 3 months and 6 months, scores were found to be statistically non-significant (P > 0.01).

Conclusion:

The results of the present study indicate that both NHA and conventional HA led to the improvement of clinical and radiographic parameters over the course of the study. However, the test group did not show any significant improvement over the control group.

Does size difference in allogeneic cancellous bone granules loaded with differentiated autologous cultured osteoblasts affect osteogenic potential?

We study the efficacy of bone regeneration by using two differently sized allogeneic cancellous bone granules loaded with autologous cultured osteoblasts in a rabbit model. Critical-sized bone defects of the radial shaft were made in 40 New Zealand White rabbits. Small allogeneic bone granules (150-300 μm in diameter) loaded with cultured differentiated autologous osteoblasts were implanted into one forearm (SBG group) and large bone granules (500-710 μm) loaded with osteoblasts were implanted into the forearm of the other side (LBG group). Radiographic evaluations were performed at 3, 6, 9 and 12 weeks and histology and micro-CT image analysis were carried out at 6 and 12 weeks post-implantation. On radiographic evaluation, the LBG group showed a higher bone quantity index at 3 and 6 weeks post-implantation (P < 0.05) but statistical significance was lost at 9 and 12 weeks. The progression of biological processes of the SBG group was faster than that of the LBG group. On micro-CT image analysis, the LBG group revealed a higher total bone volume and surface area than the SBG group at 6 weeks (P < 0.05) but the difference decreased at 12 weeks and was without statistical significance. Histological evaluation also revealed faster progression of new bone formation and maturation in the SBG group. Thus, the two differently sized allogeneic bone granules loaded with co-cultured autologous osteoblasts show no differences in the amount of bone regeneration, although the SBG group exhibits faster progression of bone regeneration and remodeling. This method might therefore provide benefits, such as a short healing time and easy application in an injectable form, in a clinical setting.

Effect of β tricalcium phosphate particle size on recombinant human platelet-derived growth factor-BB-induced regeneration of periodontal tissue in dog

The aim of this study was to investigate the effect of β tricalcium phosphate (β-TCP) particle size on recombinant human platelet-derived growth factor-BB (rhPDGF-BB)-induced regeneration of periodontal tissue in dog. The control group (rhPDGF-BB alone) was characterized by incomplete, newly formed bone. The large-particle β-TCP (L-TCP(O))/rhPDGF-BB group showed a statistically significant increase in both new bone and cementum formation compared to the small-particle β-TCP (S-TCP(G))/rhPDGF-BB group. These findings suggest that L-TCP(O)-particle promotes rhPDGF-BB-induced formation of bone and cementum.

Bone augmentation ability of autogenous bone graft particles with different sizes: a histological and micro-computed tomography study

OBJECTIVES

The purpose of this study was to investigate the augmentation process and ability of autogenous bone graft particles of two different sizes in a vertical augmentation chamber.

MATERIAL AND METHODS

The cranial bones of 24 rabbits were used. Two polytetrafluoroethylene chambers were filled with harvested bone from tibia with small bone (SB; 150-400 microm) and large bone (LB; 1.0-2.0 mm) of the same weight. Animals were sacrificed after 1, 2, 4 and 8 weeks. The samples were analyzed by micro-computed tomography (micro-CT) for quantitative analysis, and embedded in polyester resin as non-decalcified specimens for histological analysis. Total bone volume (TBV), bone height (BH) and distribution of bone structure were calculated by micro-CT.

RESULTS

Micro-CT evaluation and histology revealed a significant difference between the investigated specimens. TBV and BH of SB decreased to about 50% of the initial situation, and there was a statistically significant difference between 1 and 8 weeks. In contrast, TBV and BH of LB were almost retained at all experimental time points. Significant differences in TBV and BH were also observed between LB and SB at 8 weeks. Bone volume of SB decreased predominantly in the upper half of the chamber at 4 and 8 weeks. In the histological observations, SB showed favorable new bone formation and rapid bone resorption in a time-dependent manner during the entire experimental period. However, LB exhibited favorable morphological stability and continued new bone formation.

CONCLUSION

SB follows a smooth osteogenic process, whereas it is not effective in volume augmentation. LB is superior to SB in augmentation ability.

Bone graft materials

This article examines each class of bone grafting material based on some of the studies in each of the following categories: safety, animal research, periodontal and maxillofacial applications, skeletal grafting, and attempts to qualify the efficacy of each class of material. The article also examines some of the research being done in "tissue engineering" to get a sense of the future of bone grafting.

Influence of matrix-suspended demineralized bone on osseous repair using a critical-sized defect in the rat (Rattus norvegicus) calvarium

Demineralized freeze-dried bone (DFDB) in matrix form must be rehydrated with a carrier medium which allows for easy manipulation during periodontal surgery. The purpose of this study was to evaluate how human DFDB suspended in a polyol matrix affects new bone formation in the rat calvarium critical-sized defect (CSD) model. Fifty-five adult male Harlan Sprague-Dawley rats were assigned to 1 of 5 treatment groups: polyol, 100% DFDB, 47% DFDB/polyol, 47% DFDB, or an unfilled control. They were then placed into 8-m calvarial CSDs. The bone donor source company for the DFDB and DFDB/polyol groups was the same. Calvaria were harvested 10 weeks after surgery and evaluated histomorphometrically. The diameter of bone particles from the 3 groups containing DFDB was measured by scanning electron microscopy. There was no statistically significant difference in the percentage of bone fill between any of the groups, although the 100% DFDB group exhibited the most bone fill. The 47% DFDB/polyol and 47% DFDB groups had similar amounts of bone formation. The average size of the demineralized bone particles from the 100% DFDB group was significantly smaller than that of the other 2 groups containing DFDB. Adding a polyol to DFDB produced similar osseous regeneration in the rat calvarium defect model vs DFDB alone. Yet from a clinical standpoint, the polyol enhanced graft handling and stability. Graft particle size may have an effect on bone fill.

A Clinical Comparison of Cenobone (A Decalcified Freeze-dried Bone Allograft) with Autogenous Bone Graft in the Treatment of Two- and Three-wall Intrabony Periodontal Defects: A Human Study with Six-month Reentry

Background and aims

Complete and predictable regeneration of tissue lost as a result of infection or trauma is the ultimate goal of periodontal therapy. Various graft materials have been successfully used in the treatment of intrabony defects. The purpose of this study was to evaluate the use of a decalcified freeze-dried bone allograft (Cerabone) with the autogenous bone graft as a gold standard in the treatment of human two- or three-wall intrabony periodontal defects.

Materials and methods

This split-mouth study was done on 10 pairs of matched two- or three-wall intrabony periodontal defects with 5 mm or more probing depth and 3 mm or more depth of intrabony component following phase I therapy. In the control sites autogenous bone graft and in the test sites decalcified freeze-dried bone allograft were used.

Results

At baseline, no significant differences were found in terms of oral hygiene and defect charac-teristics. At six months, analysis showed a significant improvement in soft and hard tissue parameters for both treatment groups as compared to preoperative measurements. There were no statistical differ-ences in clinically-measured parameters between treatment groups after 6 months except for crestal resorption that increased significantly in control group (P = 0.25). Defect resolution and bone fill in the test and control groups were 2.5 ± 0.46 mm versus 2.7 ± 0.73 mm and 2 ± 0.62 mm versus 2.20 ± 0.52 mm, respectively.

Conclusion

The results of this study demonstrated that both graft materials improved clinical parameters. The comparison of the two treatment groups did not show any significant differences in clinical parameters after six months. However, because of the limited amount of intra-oral donor bone, it is preferable to use decalcified freeze-dried bone allograft.

Morphological and chemical analysis of bone substitutes by scanning electron microscopy and microanalysis by spectroscopy of dispersion energy

This study evaluated the morphological and chemical composition of the following bone substitutes: cancellous and cortical organic bovine bone with macro and microparticle size ranging from 1.0 to 2.0 mm and 0.25 to 1.0 mm, respectively; inorganic bovine bone with particle size ranging from 0.25 to 1.0 mm; hydroxyapatite with particle size ranging from 0.75 to 1.0 mm; and demineralized freeze-dried bone allograft with particle size ranging from 0.25 to 0.5 mm. The samples were sputter-coated with gold in an ion coater, the morphology was observed and particle size was measured under vacuum by scanning electron microscopy (SEM). The chemical composition was evaluated by spectroscopy of dispersion energy (EDS) microanalysis using samples without coating. SEM analysis provided visual evidence that all examined materials have irregular shape and particle sizes larger than those informed by the manufacturer. EDS microanalysis detected the presence of sodium, calcium and phosphorus that are usual elements of the bone tissue. However, mineral elements were detected in all analyzed particles of organic bovine bone except for macro cancellous organic bovine bone. These results suggest that the examined organic bovine bone cannot be considered as a pure organic material.

Autogenous particulate bone collected with a piezo-electric surgical device and bone trap: a microbiological and histomorphometric study

The aims of this study were to determine the microbiological and particle size characteristics of particulate bone collected with a piezosurgery device and bone trap, and to reduce bacterial contamination after treatment of debris with rifamycin SV. Samples were taken from 10 patients who underwent surgical extraction of their third lower molars. The ostectomy was performed with a piezosurgery device, and the debris was collected with a surgical aspiration set equipped with a bone trap. Two aliquots were taken from each sample, one of which was treated with rifamycin SV. The second aliquot, used as a control, was treated with a physiological solution. In the samples immersed in antibiotic solution, there was a statistically significant (P<0.005) reduction in bacterial contamination. The stringent protocol followed in this study has proved valid for collection of material, and treatment with rifamycin SV was found to reduce bacterial contamination in collected material.

Effects of Different Sizes of .BETA.-tricalcium Phosphate Particles on Bone Augmentation within a Titanium Cap in Rabbit Calvarium

This study evaluated the effects of different sizes of beta-TCP particles on bone augmentation within a titanium cap. In 20 rabbits, the calvarium was exposed and a circular groove was prepared. After marrow penetration, a standardized hemispherical titanium cap was placed in the circular grove. The cap was filled with small-sized (100-250 microm) or medium-sized (250-500 microm) beta-TCP particles for the experimental site and without beta-TCP for the control site. After one and three months of healing, the animals were euthanized and examined histologically. There was a statistically significant difference in the amount of mineralized bone generated between the experimental and control groups in the three-month specimens. Furthermore, the medium-sized particles showed significantly more mineralized bone than did the small-sized particles. Based on these findings, we suggested that beta-TCP might be effective for bone formation and that medium-sized particles are more useful than small-sized particles in bone maturation.

The efficacy of bone replacement grafts in the treatment of periodontal osseous defects. A systematic review

BACKGROUND

Bone replacement grafts (BRG) are widely used in the treatment of periodontal osseous defects; however, the clinical benefits of this therapeutic practice require further clarification through a systematic review of randomized controlled studies.

RATIONALE

The purpose of this systematic review is to access the efficacy of bone replacement grafts in proving demonstrable clinical improvements in periodontal osseous defects compared to surgical debridement alone.

FOCUSED QUESTION

What is the effect of bone replacement grafts compared to other interventions on clinical, radiographic, adverse, and patient-centered outcomes in patients with periodontal osseous defects?

SEARCH PROTOCOL

The computerized bibliographical databases MEDLINE and EMBASE were searched from 1966 and 1974, respectively, to October 2002 for randomized controlled studies in which bone replacement grafts were compared to other surgical interventions in the treatment of periodontal osseous defects. The search strategy included screening of review articles and reference lists of retrieved articles as well as hand searches of selected journals.

INCLUSION CRITERIA

All searches were limited to human studies in English language publications.

EXCLUSION CRITERIA

Non-randomized observational studies (e.g., case reports, case series), publications providing summary statistics without variance estimates or data to permit computation, and studies without BRG intervention alone were excluded.

DATA COLLECTION AND ANALYSIS

The therapeutic endpoints examined included changes in bone level, clinical attachment level, probing depth, gingival recession, and crestal resorption. For purposes of meta-analysis, change in bone level (bone fill) was used as the primary outcome measure, measured upon surgical re-entry or transgingival probing (sounding).

MAIN RESULTS

1. Forty-nine controlled studies met eligibility criteria and provided clinical outcome data on intrabony defects following grafting procedures. 2. Seventeen studies provided clinical outcome data on BRG materials for the treatment of furcation defects.

REVIEWERS' CONCLUSIONS

1. With respect to the treatment of intrabony defects, the results of meta-analysis supported the following conclusions: 1) bone grafts increase bone level, reduce crestal bone loss, increase clinical attachment level, and reduce probing depth compared to open flap debridement (OFD) procedures; 2) No differences in clinical outcome measures emerge between particulate bone allograft and calcium phosphate (hydroxyapatite) ceramic grafts; and 3) bone grafts in combination with barrier membranes increase clinical attachment level and reduce probing depth compared to graft alone. 2. With respect to the treatment of furcation defects, 15 controlled studies provided data on clinical outcomes. Insufficient studies of comparable design were available to submit data to meta-analysis. Nonetheless, outcome data from these studies generally indicated positive clinical benefits with the use of grafts in the treatment of Class II furcations. 3. With respect to histological outcome parameters, 2 randomized controlled studies provide evidence that demineralized freeze-dried bone allograft (DFDBA) supports the formation of a new attachment apparatus in intrabony defects, whereas OFD results in periodontal repair characterized primarily by the formation of a long junctional epithelial attachment. Multiple observational studies provide consistent histological evidence that autogenous and demineralized allogeneic bone grafts support the formation of new attachment. Limited data also suggest that xenogenic bone grafts can support the formation of a new attachment apparatus. In contrast, essentially all available data indicate that alloplastic grafts support periodontal repair rather than regeneration. 4. The results of this systematic review indicate that bone replacement grafts provide demonstrable clinical improvements in periodontal osseous defects compared to surgical debridement alone.

Comparison of Porous and Non-Porous Teflon Membranes Plus a Xenograft in the Treatment of Vertical Osseous Defects: A Clinical Reentry Study

BACKGROUND

The primary aim of this 9-month randomized, controlled, blinded, clinical reentry study was to compare the regenerative effects of a nonporous polytetrafluoroethylene (NP) periodontal membrane to a porous expanded polytetrafluoroethylene (P) periodontal membrane in the treatment of vertical osseous defects.

METHODS

Twenty-four patients, 11 males and 13 females, age 24 to 74 (mean 50.5 +/- 13.1) provided one site with an intraosseous defect > or = 4 mm and were divided equally and randomly into two groups. Following debridement both groups were grafted with a bovine-derived xenograft coated with a synthetic cell-binding peptide; then the test group received an NP membrane and the control group received a P membrane. All defects were reentered after 9 months. Measurements were performed by a masked examiner.

RESULTS

There were no statistically significant differences (P>0.05) between NP and P groups for any open or closed probing measurement at any time. Similar open initial defect depth for the NP group and P groups (4.8 versus 5.0 mm) demonstrated identical 9-month defect fill of 2.8 mm (57%) for both groups. A difference in crestal resorption for the NP compared to the P group (0.4 versus 0.8 mm) accounted for the difference in mean percent defect resolution, which was 67% for NP compared to 72% for the P group. Overall, nine (75%) of the NP group defects and eight (67%) of the P group defects showed more than 50% defect fill.

CONCLUSION

Treatment of vertical osseous defects with nonporous or porous polytetrafluoroethylene membranes in combination with a xenograft resulted in statistically significant improvement in open and closed probing measurements, with no significant difference between treatment groups.

A composite graft material containing bone particles and collagen in osteoinduction in mouse

Demineralized allogenic bone matrices (DABM) and demineralized freeze-dried bone allograft (DFDBA) have been successfully used as bone-graft materials in the treatment of acquired and congenital cranio-maxillofacial defects and in some orthopedic surgery. However, these bone-graft "powders" have many shortcomings. For example, placement of particulate graft material in a hemorrhaging site can result in inadequacies or inaccurate attachment as well as loss of the graft materials. To minimize the inadequacies of powderlike graft materials, xenogenic collagen isolated from human tendon, skin, or bone was added to the bone-graft particles to form a composite spongelike implant. This material is commercially available and consists of 60% collagen and 40% DFDBA (DynaGraft, GenSci Co., Irvine, CA). The goal of this study was to evaluate the characteristics of composite graft implants in the mineralization process in an animal model in comparison with DFDBA powder and pure collagen. Seventy-two Swiss Webster mice were divided into three groups: an experimental group implanted with DynaGraft, two comparison groups implanted with either DFDBA or collagen only. All the graft materials were surgically implanted and inserted into the left thigh muscle. Mice were humanely killed at 1, 2, 3, 4, 6, 8, and 12 weeks. Then the muscle tissues in the vicinity of the implants were excised and processed for histology. Paraffin sections were stained with hematoxylin and eosin (H&E), the Von Kossa method, and Masson's trichrome. Some selected specimens were processed for transmission electron microscopic observation. After 1 week of implantation, the DynaGraft group showed calcium deposition on the collagen material and on the periphery of the DFDBA particles. Increased calcification and bone-forming cells were observed at 4-6 weeks. After 8 weeks, the implant formed a calcified nodule and only heavily mineralized connective tissue was observed at the implanted site. The group implanted with DFDBA powder showed calcification around the particulates. The collagen-sponge control group revealed no calcification or bone formation during the period of implantation. The light microscopic findings were confirmed by electron microscopy. Quantitative radiographic density DynaGraft and DFDBA graft followed sequentially over a period 120 days. It was concluded that a higher rate of calcification and bone formation was produced in the composite graft implant compared to the DFDBA implant. The composite graft material (DynaGraft), which contains both collagen and DFDBA, proved to be more effective for bone formation than particle components alone.

Identification of Bone Morphogenetic Proteins 2 and 4 in Commercial Demineralized Freeze-dried Bone Allograft Preparations: Pilot Study

BACKGROUND

Demineralized freeze-dried bone allografts (DFDBAs) have been proposed as a useful adjunct in periodontal therapy to induce periodontal regeneration through the induction of new bone formation. The presence of bone morphogenetic proteins (BMPs) within the demineralized matrix has been proposed as a possible mechanism through which DFDBA may exert its biologic effect. However, in recent years, the predictability of results using DFDBA has been variable and has led to its use being questioned. One reason for the variability in tissue response may be attributed to differences in the processing of DFDBA, which may lead to loss of activity of any bioactive substances within the DFDBA matrix. Therefore, the purpose of this investigation was to determine whether there are detectable levels of bone morphogenetic proteins in commercial DFDBA preparations.

METHODS

A single preparation of DFDBA was obtained from three commercial sources. Each preparation was studied in triplicate. Proteins within the DFDBA samples were first extracted with 4M guanidinium HCI for seven days at 40 degrees celsius and the residue was further extracted with 4M guanidinium HCL/EDTA for seven days at 40 degrees celsius. Two anti-human BMP-2 and -4 antibodies were used for the detection of the presence of BMP's in the extracts.

RESULTS

Neither BMP-2 nor BMP-4 was detected in any of the extracts. When recombinant human BMP-2 and -4 were added throughout the extraction process of DFDBA extraction, not only were intact proteins detected but smaller molecular weight fragments were also noted in the extract.

CONCLUSIONS

These results indicate that all of the DFDBA samples tested had no detectable amounts of BMP-2 and -4. In addition, an unknown substance present in the DFDBA may be responsible for degradation of whatever BMPs might be present.

Comparison of bioactive glass to demineralized freeze-dried bone allograft in the treatment of intrabony defects around implants in the canine mandible

BACKGROUND

The purpose of this study was to evaluate and compare the healing of different bone grafting materials adjacent to titanium plasma-sprayed (TPS) endosseous dental implants.

METHODS

Implant osteotomy sites were prepared and standardized 3-walled intrabony defects (3 mm x 5 mm x 5 mm) were created at the mesial of each implant site. Thirty-two TPS implants were placed in edentulous mandibular ridges of the 4 dogs. Periodontal dressings were placed in the defect sites so as to create a defect simulating bone loss around an implant. After 3 months, the periodontal dressing was removed, the defect sites debrided and evaluated for size, and intramarrow penetration performed. The graft materials tested were 1) canine demineralized freeze-dried bone allograft (cDFDBA); 2) bioactive glass granules of a broad size range 90 to 710 microns (BRG); and 3) bioactive glass granules of narrow size range 300 to 355 microns (NRG). One site on each side of the mandible was not filled and served as a control. Dogs were sacrificed 4 months after graft placement.

RESULTS

Histologically, differences in percent bone-to-implant contact in the defect area were observed between the treatment groups. cDFDBA>control=BRG=NRG with statistical significance found between cDFDBA and control (P = 0.0379), but no statistically significant difference between control or either bioactive glass material. When comparing percent bone height fill of the defect in the grafted area, cDFDBA (65.7%) was significantly better than the control (48.9%; P < or = 0.05) with no statistically significant difference between control, broad range bioactive glass (57.3%) and narrow range bioactive glass (56.6%). When total bone area was measured, the percentage of new bone in the grafted area was cDFDBA (42.1%), broad range glass (33.1%) and narrow range glass (22.6%) with significance found between cDFDBA and NRG (P = 0.0102). The content of residual graft particles in soft tissue was significant (P = 0.0304) between cDFDBA (1.4%) and NRG (11.4%) with no significant difference between graft material for residual particle content in bone tissue.

CONCLUSIONS

The results of this study indicate that percent bone-to-implant contact and percent bone height fill in an intrabony defect around titanium plasma-sprayed implants are statistically significantly higher with the use of DFDBA when compared to bioactive glass material.

Bone and bone substitutes

Bone replacement grafts will play a continuing role in periodontal and other regenerative therapy. Several choices are available to the clinician including autogenous, allogeneic, xenogeneic and a variety of alloplastic materials. Except for fresh autogenous bone, bone replacement graft(s) do not provide the cellular elements necessary for osteogenesis nor can they reliably be considered truly osteoinductive, but instead are mostly osteoconductive, providing a scaffold for bone deposition. Currently, significant decrease in clinical probing depth and gain of clinical attachment have been reported following use of bone replacement grafts when compared to flap debridement surgery alone for periodontal osseous defects. Reported differences among bone replacement grafts (autogenous, allogeneic, xenogeneic, and alloplastic) occur with respect to histological outcomes. Overall, probing depth reduction, attachment level gain and degree of defect fill are similar for all bone replacement grafts.

Periodontal regeneration around natural teeth

1. Evidence is conclusive (Table 2) that periodontal regeneration in humans is possible following the use of bone grafts, guided tissue regeneration procedures, both without and in combination with bone grafts, and root demineralization procedures. 2. Clinically guided tissue regeneration procedures have demonstrated significant positive clinical change beyond that achieved with debridement alone in treating mandibular and maxillary (buccal only) Class II furcations. Similar data exist for intraosseous defects. Evidence suggests that the use of bone grafts or GTR procedures produce equal clinical benefit in treating intraosseous defects. Further research is necessary to evaluate GTR procedures compared to, or combined with, bone grafts in treating intraosseous defects. 3. Although there are some data suggesting hopeful results in Class II furcations, the clinical advantage of procedures combining present regenerative techniques remains to be demonstrated. Additional randomized controlled trials with sufficient power are needed to demonstrate the potential usefulness of these techniques. 4. Outcomes following regenerative attempts remain somewhat variable with differences in results between studies and individual subjects. Some of this variability is likely patient related in terms of compliance with plaque control and maintenance procedures, as well as personal habits; e.g., smoking. Variations in the defects selected for study may also affect predictability of outcomes along with other factors. 5. There is evidence to suggest that present regenerative techniques lead to significant amounts of regeneration at localized sites on specific teeth. However, if complete regeneration is to become a reality, additional stimuli to enhance the regenerative process are likely needed. Perhaps this will be accomplished in the future, with combined procedures that include appropriate polypeptide growth factors or tissue factors to provide additional stimulus.

Bone allografts in periodontal therapy

Bone allografts as used in dentistry have a 20-year history of safety and efficacy. Case reports and controlled clinical trials have shown the potential of both mineralized and decalcified cortical freeze-dried bone allograft to reconstruct the bone defects caused by periodontitis. Histomorphometric analysis of human biopsies following grafts of decalcified freeze-dried bone allograft have shown the ability of decalcified freeze-dried bone allograft to promote regeneration of new bone, cementum, and periodontal ligament on a tooth root surface previously exposed to bacterial plaque. The addition of mineralized freeze-dried bone allograft and decalcified freeze-dried bone allograft to the guided tissue and guided bone regeneration procedures have significantly enhanced results, especially in large osseous lesions.