Comparison of bone graft materials. Part I. New bone formation with autografts and allografts determined by Strontium-85

Ridge Preservation and Augmentation Using a Carbonated Apatite Bone Graft Substitute: A Case Series

The newly developed mineral carbonated apatite has recently been proposed as a bone graft material for bone regenerative treatment in implant therapy. This case series details the clinical and radiographic outcomes of ridge preservation and ridge augmentation using only carbonated apatite as bone graft material for implant treatment. Twenty patients (36 sites) who required bone regeneration and implant placement were retrospectively assessed. Simultaneous carbonated apatite implant placement was performed using the simultaneous ridge preservation or augmentation approach on 24 sites in 13 patients with sufficient bone quantity for primary stabilization based on preoperative evaluation results. A staged ridge preservation or augmentation approach was used for the remaining 12 sites in seven patients with insufficient bone quantity. The mean regenerated bone height for each treatment method was as follows: simultaneous preservation, 7.4 ± 3.3 mm; simultaneous augmentation, 3.6 ± 2.3 mm; staged preservation, 7.2 ± 4.5 mm; and staged augmentation, 6.1 ± 2.7 mm. The mean regenerated bone width for each treatment method was as follows: simultaneous preservation, 6.5 ± 2.9 mm; simultaneous augmentation, 3.3 ± 2.5 mm; staged preservation, 5.5 ± 1.7 mm; and staged augmentation, 3.5 ± 1.9 mm. Ultimately, the use of carbonated apatite alone as a bone graft material in implant therapy resulted in stable and favorable bone regeneration.

Biomaterials for Alveolar Ridge Preservation as a Preoperative Procedure for Implant Treatment: History and Current Evidence

In implant treatment, the reduction and structural changes in the alveolar ridge that occur after tooth extraction limit the length, width, and placement position of the implant body, impair esthetics, and, in some cases, make implant placement difficult. To solve these problems, an alveolar ridge preservation (ARP) technique, which is performed simultaneously with tooth extraction, generally aims to promote bone regeneration and prevent alveolar ridge reduction by filling the extraction socket with bone graft material and then covering it with a barrier membrane to protect against the invasion of epithelial tissue. The extraction socket provides a favorable environment for bone regeneration throughout the healing period because the blood supply is abundant, and it effectively retains the bone graft material by using the remaining bone wall of the socket. In recent years, advances in bioengineering technology have led to the development of graft materials with various biological properties, but there is currently no clear consensus regarding the selection of surgical techniques and materials depending on the condition of the alveolar ridge. This review will provide a comprehensive survey of the evidence accumulated to date on ARP, present many cases according to the clinical situation, and discuss various treatment options.

Polymeric Scaffolds for Dental, Oral, and Craniofacial Regenerative Medicine

Dental, oral, and craniofacial (DOC) regenerative medicine aims to repair or regenerate DOC tissues including teeth, dental pulp, periodontal tissues, salivary gland, temporomandibular joint (TMJ), hard (bone, cartilage), and soft (muscle, nerve, skin) tissues of the craniofacial complex. Polymeric materials have a broad range of applications in biomedical engineering and regenerative medicine functioning as tissue engineering scaffolds, carriers for cell-based therapies, and biomedical devices for delivery of drugs and biologics. The focus of this review is to discuss the properties and clinical indications of polymeric scaffold materials and extracellular matrix technologies for DOC regenerative medicine. More specifically, this review outlines the key properties, advantages and drawbacks of natural polymers including alginate, cellulose, chitosan, silk, collagen, gelatin, fibrin, laminin, decellularized extracellular matrix, and hyaluronic acid, as well as synthetic polymers including polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), poly (ethylene glycol) (PEG), and Zwitterionic polymers. This review highlights key clinical applications of polymeric scaffolding materials to repair and/or regenerate various DOC tissues. Particularly, polymeric materials used in clinical procedures are discussed including alveolar ridge preservation, vertical and horizontal ridge augmentation, maxillary sinus augmentation, TMJ reconstruction, periodontal regeneration, periodontal/peri-implant plastic surgery, regenerative endodontics. In addition, polymeric scaffolds application in whole tooth and salivary gland regeneration are discussed.

Periodontal approach in the management of alveolar cleft

The alveolar cleft is a bone-related developmental defect in the alveolar process of the maxillae, which is termed as cleft alveolus. The deformity occurs in 75% of the cleft palate and lip patients. Reconstructive surgery can provide both functional and esthetic benefits to such individuals. Conflicting opinions exist on the management of alveolar cleft, and these affect the treatment planning. We present the case of a 19-year-old female patient with a complaint of mobile teeth in the left frontal region of the upper jaw. On clinical examination, unilateral cleft alveolus was observed between the left lateral incisor and the canine region. A multidisciplinary approach was adopted, orthodontic treatment was started, and periodontal regenerative surgery was planned. This report also discusses the substitution of autogenous bone grafts with other materials such as allogenic grafts (demineralized freeze-dried bone allograft), platelet-rich plasma, platelet-rich fibrin membranes, and amnion membranes, which could serve as a new line of treatment for the condition.

Morphological Characteristics of the Osteoplastic Potential of Synthetic CaSiO3/HAp Powder Biocomposite

The study describes the influence of synthetic CaSiO₃/HAp powder biocomposite on the process of regeneration in osseous tissue in the alveolar ridges in terms of the morphological characteristics of the osteoplastic potential. The authors investigated the osteoinduction and osteoconduction “in vivo” processes during bone tissue regeneration in the mandible defect area of an experimental animal (rabbit). The possibility of angiogenesis in the graft as an adaptation factor was studied in the process of bone tissue regeneration. The results of the histological study that included the qualitative parameters of bone tissue regeneration, the morphometric parameters (microarchitectonics) of the bone, the parameters of osteosynthesis (thickness of the osteoid plates), and resorption (volume density of the eroded surface) were presented. The results allowed the authors to characterize the possibility of the practical adaptation for synthetic powder biocomposite as an osteoplastic graft for the rehabilitation of osseous defects in dentistry.

Treatment of a Mandibular Periodontal Interproximal Defect with a Bone Graft in a Dog

A 10-year-old German shepherd dog presented with a periodontal 10 mm interproximal defect between the left mandibular fourth premolar and first molar teeth. Bone graft removed from the caudoventral portion of the ipsilateral hemimandible was placed in the defect as a component of the periodontal treatment plan. The use of bone graft likely contributed to periodontal pocket reduction.

Bone-implant-contact and new bone formation around implants placed in FDB blocks compared to placement at the adjunction of particulate FDB

BACKGROUND

The efficacy of human freeze-dried bone (h-FDB) as particulate vs block forms as a proper onlay augmented bone graft material to accommodate implants is undetermined.

PURPOSE

To evaluate osseointegration and new bone formation at implants placed in FDB blocks (BL group) and those at the adjunction of particulate FDB (PR group).

MATERIALS AND METHODS

Twelve pairs of h-FDB blocks were stabilized bilaterally to the calvaria of 12 rabbits. Twenty-four SLA implants were placed at the remodeled grafted blocks, 4 months later. A circumferential gap was created around one implant in each pair and packed with particulate h-FDB. Section biopsies were obtained at 2-month post implant placement (6 months post-block grafting). Bone-to-implant contact (BIC) and bone-area fraction (BAF) were histomorphometrically calculated.

RESULTS

The mean BIC was 34.4% and 33.5% for the BL and PR groups, respectively. The mean BAF was 23.9% and 26.4% for the corresponding groups, respectively. Osseointegration and newly formed bone were evident mostly between the threaded portions of the implants in proximity to the host rabbit calvaria compared to its cervical neck.

CONCLUSION

The particulate and the cancellous block h-FDB forms yielded similar BIC and BAF outcome. Full revascularization/revitalization is questioned.

Evaluation of the Success of β-Tricalciumphosphate and Deproteinized Bovine Bone in Maxillary Sinus Augmentation Using Histomorphometry: A Review

Sinus lift operations have become a prerequisite for implantologists in the rehabilitation of atrophic posterior maxilla. Alloplasts and xenografts are the recent innovation in the world of grafting materials and have evolved in such a way as to compensate the need for autografts to be used in conjunction. In order to perfect the grafting materials, histomorphometry is the most often tool used to study the success of the augmentation. This article has tried to commemorate the importance of histomorphometry in maxillary antroplasty and also the success rate of β-tricalciumphosphate and deproteinized bovine bone as an augmentation material in maxillary augmentation.

Natural graft tissues and synthetic biomaterials for periodontal and alveolar bone reconstructive applications: a review

Periodontal disease is categorized by the destruction of periodontal tissues. Over the years, there have been several clinical techniques and material options that been investigated for periodontal defect repair/regeneration. The development of improved biomaterials for periodontal tissue engineering has significantly improved the available treatment options and their clinical results. Bone replacement graft materials, barrier membranes, various growth factors and combination of these have been used. The available bone tissue replacement materials commonly used include autografts, allografts, xenografts and alloplasts. These graft materials mostly function as osteogenic, osteoinductive and/or osteoconductive scaffolds. Polymers (natural and synthetic) are more widely used as a barrier material in guided tissue regeneration (GTR) and guided bone regeneration (GBR) applications. They work on the principle of epithelial cell exclusion to allow periodontal ligament and alveolar bone cells to repopulate the defect before the normally faster epithelial cells. However, in an attempt to overcome complications related to the epithelial down-growth and/or collapse of the non-rigid barrier membrane and to maintain space, clinicians commonly use a combination of membranes with hard tissue grafts. This article aims to review various available natural tissues and biomaterial based bone replacement graft and membrane options used in periodontal regeneration applications.

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.

Histologic and histomorphometric evaluation of two grafting materials Cenobone and ITB-MBA in open sinus lift surgery

Aims and Objectives:

Alveolar ridge reduction caused after tooth extraction can be minimized through ridge preservation and application of graft materials. The aim of this study was to compare the histologic and histomorphometric aspects of bone particulated allografts, Cenobone and ITB-MBA, in the reconstruction of vertical alveolar ridge after maxillary sinus augmentation.

Materials and Methods:

This clinical trial was performed among 20 patients. The participants were randomly divided into two groups of 10 participants. The first group received Cenobone and the second group received ITB-MBA. Tissue samples were prepared 6 months later at the time of implant installation and after successful maxillary sinus floor augmentation. Tissue sections were examined under a light microscope. The data were analyzed by Chi-square and t-test.

Results:

The mean trabecular thickness of the samples in the Cenobone group was 13.61 ± 7.47 μm compared to 13.73 ± 7.37 μm in the ITB-MBA group (P = 0.93). A mild inflammation process (Grade 1) was detected in both the groups. The amount of remaining biomaterial in the Cenobone group was estimated to be 8 ± 19% vs. 7 ± 12% in the ITB-MBA group (P = 0.30). Bone formation was reported 49.71% in the Cenobone group vs. 40.76% in the ITB-MBA group (P = 0.68). The mean newly formed vessel in the Cenobone group was 0.64 ± 0.7 vs. 1.5 ± 2.3 in the ITB-MBA group (P = 0.14).

Conclusions:

There was no significant difference between the two groups of patients regarding trabecular thickness, remaining biomaterial allograft, and the density of blood vessels after sinus floor elevation; hence, there was no difference between the two groups regarding implant outcome. More designed studies as randomized controlled trials and controlled clinical trials, which evaluate the long-term implant outcome; comparing the different bone graft materials is also required to improve evidence on survival and success rate.

The role of angiogenesis in implant dentistry part II: The effect of bone-grafting and barrier membrane materials on angiogenesis

BACKGROUND

In implant dentistry, bone substitute materials and barrier membranes are used in different treatments including guided bone regeneration (GBR), socket preservation, alveolar ridge augmentation, maxillary sinus elevation, and filling bony defects around the inserted dental implant. One of the most important factors in prognosis of treatments using these materials is the growth of new blood vessels in applied areas. Present review was performed to evaluate the effect of the bone-grafting and barrier membrane materials on angiogenesis events.

MATERIAL AND METHODS

An electronic search was performed in PubMed, MEDLINE, and EMBASE databases via OVID using the keywords mentioned in the PubMed and MeSH headings regarding the role of angiogenesis in implant dentistry from January 2000-April 2014.

RESULTS

Of the 5,622 articles identified in our initial search results, only 33 met the inclusion criteria set for this review. Among bone substitute materials the autogenous bone-grafts, and among the barrier membranes the collagenous membranes, had the highest angiogenic potentials. Other bone-grafting materials or membranes were mostly used with pro-angiogenic factors to enhance their angiogenic properties.

CONCLUSIONS

Angiogenesis is one of the key factors, which plays a critical role in success rate of GBR technique and is seriously considered in manufacturing bone-grafting and barrier membrane materials. However, there is still lack of clinical and in-vivo studies addressing the effect of angiogenesis in treatments using bone-grafting and barrier membrane materials.

A randomized controlled evaluation of alveolar ridge preservation following tooth extraction using deproteinized bovine bone mineral and demineralized freeze-dried bone allograft

Background:

Alveolar ridge preservation could be performed immediately following tooth extraction to limit dimensional changes of alveolar process due to bone resorption. The aim of this study was to compare the clinical and histologic outcomes of socket preservation using two different graft materials; deproteinized bovine bone mineral (DBBM) and demineralized freeze-dried bone allograft (DFDBA) with absorbable collagen membrane.

Materials and Methods:

Twenty extraction sockets in 20 patients were randomly divided into 2 treatment groups: 10 sockets were augmented with DBBM and collagen membrane whereas 10 sockets were filled with DFDBA and covered by collagen membrane. Primary closure was achieved over extraction sockets by flap advancement. Horizontal and vertical ridge dimensional changes were assessed at baseline and after 4-6 months at the time of implant placement. For histological and histomorphometrical analysis, bone samples were harvested from the augmented sites with trephine during implant surgery. All data were analyzed using SPSS version 18 (α=0.05).

Results:

Clinical measurements revealed that average horizontal reduction was 2.3 ± 0.64 mm for DFDBA and 2.26 ± 0.51 mm for DBBM. Mean vertical ridge resorption at buccal side was 1.29 ± 0.68 mm for DFDBA and 1.1 ± 0.17 mm for DBBM. Moreover, mean vertical ridge reduction at lingual site was 0.41 ± 0.38 mm and 0.35 ± 0.34 mm for DFDBA and DBBM, respectively. No significant differences were seen between two groups in any of those clinical parameters. Histologic analysis showed statistically significant more new bone deposition for DFDBA compared to DBBM (34.49 ± 3.19 vs. 18.76 ± 3.54) (P < 0.01). Residual graft particles were identified significantly more in DBBM (12.77 ± 1.85) than DFDBA (6.06 ± 1.02).

Conclusion:

Based on the findings of this study, both materials have positive effect on alveolar ridge preservation after tooth extraction, but there was more new bone formation and less residual graft particles in DFDBA group than in DBBM group.

Vertical Bone Growth after Autotransplantation of Mature Third Molars: 2 Case Reports with Long-term Follow-up

Tooth autotransplantation is a viable treatment option for tooth replacement when a suitable donor tooth is available. These case reports described significant vertical bone growth after autotransplantation of a mature third molar. The left mandible third molars (n = 2) were transplanted to the missing tooth in the left mandible. The patient follow-up period was 10 years after transplantation. Clinical examination revealed no mobility of the transplanted tooth. Radiographic examination indicated that bone regeneration occurred around the transplanted tooth. Vertical bone growth was observed in the cervical area of the root surface and the recipient bone. In autotransplantation of mature teeth, long-term follow-up results indicate that vertical bone growth can be expected if viability of the periodontal ligament cells is maintained.

A clinical and radiological evaluation of the relative efficacy of demineralized freeze-dried bone allograft versus anorganic bovine bone xenograft in the treatment of human infrabony periodontal defects: A 6 months follow-up study

Background:

The ultimate goal of periodontal therapy entails regeneration of the periodontal tissues lost as a consequence of periodontitis. Predictable correction of vertical osseous defects has however posed as a constant therapeutic challenge. The aim of our present study is to evaluate the relative efficacy of demineralized freeze-dried bone allograft (DFDBA) vs anorganic bovine bone xenograft (ABBX) in the treatment of human infrabony periodontal defects.

Materials and Methods:

15 patients with 30 bilaterally symmetrical defect sites in either of the arches, in the age group of 25-50 years were selected as part of split-mouth study design. Defect-A (right side) was grafted with DFDBA while Defect-B (left side) was grafted with ABBX. Various clinical and radiographic parameters viz. probing depth(PD), clinical attachment level(CAL) and linear bone fill were recorded preoperatively, 12- & 24-weeks postoperatively.

Results:

Both defect-A & defect-B sites exhibited a highly significant reduction in probing depth, and gain in clinical attachment level and linear bone fill at 12-weeks & at the end of 24-weeks. Comparative evaluation between the study groups revealed a statistically non-significant reduction in probing depth (P<0.1) and mean gain in linear bone fill (P<0.1). However, there was a statistically significant gain in clinical attachment level (P<0.05) in Defect-A (CD=0.356) as compared to Defect-B (CD=0.346).

Conclusions:

Within the limits of this study, both the materials viz. ABBX and DFDBA are beneficial for the treatment of periodontal infrabony defects. Both the materials were found to be equally effective in all respects except the gain in attachment level, which was found to be more with DFDBA. Long-term studies are suggested to evaluate further the relative efficacy of the two grafts.

Mechanisms of guided bone regeneration: a review

Post-extraction crestal bone resorption is common and unavoidable which can lead to significant ridge dimensional changes. To regenerate enough bone for successful implant placement, Guided Bone Regeneration (GBR) is often required. GBR is a surgical procedure that uses barrier membranes with or without particulate bone grafts or/and bone substitutes. There are two approaches of GBR in implant therapy: GBR at implant placement (simultaneous approach) and GBR before implant placement to increase the alveolar ridge or improve ridge morphology (staged approach). Angiogenesis and ample blood supply play a critical role in promoting bone regeneration.

Assessment of the autogenous bone graft for sinus elevation

OBJECTIVES

The posterior maxillary region often provides a limited bone volume for dental implants. Maxillary sinus elevation via inserting a bone graft through a window opened in the lateral sinus wall has become the most common surgical procedure for increasing the alveolar bone height in place of dental implants in the posterior maxillary region. The purpose of this article is to assess the change of bone volume and the clinical effects of dental implant placement in sites with maxillary sinus floor elevation and autogenous bone graft through the lateral window approach.

MATERIALS AND METHODS

In this article, the analysis data were collected from 64 dental implants that were placed in 24 patients with 29 lacks of the bone volume posterior maxillary region from June 2004 to April 2011, at the Department of Oral and Maxillofacial Surgery, Inha University Hospital. Panoramic views were taken before the surgery, after the surgery, 6 months after the surgery, and at the time of the final follow-up. The influence of the factors on the grafted bone material resorption rate was evaluated according to the patient characteristics (age and gender), graft material, implant installation stage, implant size, implant placement region, local infection, surgical complication, and residual alveolar bone height.

RESULTS

The bone graft resorption rate of male patients at the final follow-up was significantly higher than the rate of female patients. The single autogenous bone-grafted site was significantly more resorbed than the autogenous bone combined with the Bio-Oss grafted site. The implant installation stage and residual alveolar height showed a significant correlation with the resorption rate of maxillary sinus bone graft material. The success rate and survival rate of the implant were 92.2% and 100%, respectively.

CONCLUSION

Maxillary sinus elevation procedure with autogenous bone graft or autogenous bone in combination with Bio-Oss is a predictable treatment method for implant rehabilitation.

Determination of orthodontic tooth movement and tissue reaction following demineralized freeze-dried bone allograft grafting intervention

BACKGROUND

Socket preservation after tooth extraction is one of the indications of bone grafting to enhance preorthodontic condition. The aim of this study is to determine the effects of socket preservation on the immediate tooth movement, alveolar ridge height preservation and orthodontic root resorption.

MATERIALS AND METHODS

In a split-mouth technique, twelve sites in three dogs were investigated as an experimental study. Crushed demineralized freeze-dried bone allograft (DFDBA) (CenoBone(®)) was used as the graft material. The defects were made by the extraction of 3(rd) premolar. On one side of each jaw, the defects were preserved by DFDBA and defects of the other side left opened as the control group. Simultaneously the teeth adjacent to the defects were pulled together by a NiTi coil spring. After eight weeks, the amount of (OTM), alveolar height, and root resorption were measured. Analysis of variance was used for purpose of comparison.

RESULTS

There was a slight increase in OTM at grafted sites as they were compared to the control sites (P<0.05). Also a significant bone resorption in control site and successful socket preservation in experimental site were observed. Reduction of root resorption at the augmented site was significant compared to the normal healing site (P<0.05).

CONCLUSION

Using socket preservation, tooth movement can be immediately started without waiting for the healing of the recipient site. This can provide some advantages like enhanced rate of OTM, its approved effects on ridge preservation that reduces the chance of dehiscence and the reduction of root resorption.

Generalized aggressive periodontitis and its treatment options: case reports and review of the literature

Generalized aggressive periodontitis results in rapid destruction of the periodontium and can lead to early tooth loss in the affected individuals if not diagnosed early and treated appropriately. The diagnostic features of the disease are characteristic, but the clinical presentation and patterns of destructions may vary between patients. Successful management of the disease is challenging especially if diagnosed at advanced stages of the disease, but not impossible with the current therapeutic choices for the disease. A vast array of treatment modalities is available which can be employed in the treatment of generalized aggressive periodontitis with varying success rates, but a definite guideline for the management is yet to be formulated. However, with the exponential rate of developments in periodontal research, regenerative therapy, tissue engineering, and genetic technologies, the future seems promising in regard to options at managing the disease. This paper attempts to describe the clinical and radiographic diagnostic features and the current treatment options along with a suggested protocol for comprehensive management of generalized aggressive periodontitis patients with case reports and a brief review.

The role of hydroxyapatite in citric acid-based nanocomposites: surface characteristics, degradation, and osteogenicity in vitro

The incorporation of nanoscale hydroxyapatite (HA) into biodegradable polymers can potentially mimic the native structure of bone and influence the mechanical properties and the extent of bioactivity. In this study nanocomposites of poly(1,8-octanediol-co-citrate) (POC) containing 40, 50, and 60 wt.% HA (POC-HA) were fabricated and characterized. Nanocomposite hydrophilicity and the degradation properties in vitro were evaluated via contact angle measurements, scanning electron microscopy (SEM), and mass loss measurements. Human mesenchymal stem cells (hMSC) were cultured on POC-HA nanocomposites in both growth and osteogenic media. Cell proliferation, alkaline phosphatase activity, and osteocalcin were measured. The equilibrium water in air contact angles confirmed all of the nanocomposites to be hydrophilic (23.4 ± 8.1°, 27 ± 9.1°, and 27.7 ± 3.5° for 40, 50, and 60 wt.% HA, respectively). Over a period of 26 weeks the degradation rate increased with decreasing HA content and pore formation was evident for POC-HA containing 40 wt.% HA, whereas POC with 50 and 60 wt.% HA lacked pores (mass loss at 26 weeks for 40, 50, and 60 wt.% HA, 27.4 ± 1.6%, 17.7 ± 1.6%, and 6.3 ± 2.6%, respectively). hMSC adhered and proliferated well on all composites, confirming biocompatibility for at least 21 days. An increase in adhesion and proliferation was found with increasing HA nanoparticle content (ng DNA at day 21 for 40, 50, and 60 wt.% HA, 130.4 ± 49.4, 184.4 ± 86.4, 314.1 ± 92.3). Alkaline phosphatase activity and osteocalcin concentration correlated with HA content (alkaline phosphate activity in expansion medium and osteogenic medium for 40, 50, and 60 wt.% HA, 256.1 ± 71.8%, 304.0 ± 128.7%, and 500.2 ± 89.9%, and 358.4 ± 124.1%, 653.7 ± 216.5%, and 814.4 ± 68.8%, respectively; osteocalcin concentration in expansion medium and osteogenic medium for 40, 50, and 60 wt.% HA, 236.9 ± 7.8%, 253.0 ± 7.5%, and 285.2 ± 11.4%, and 265.8 ± 15.0%, 288.3 ± 17.9%, and 717.3 ± 38.7%, respectively). This study provides insight into how the HA nanoparticle content can modulate the cell compatibility and physical properties of POC-HA nanocomposites.

Bone regeneration effects of human allogenous bone substitutes: a preliminary study

Purpose

The purpose of this study was to compare the bone regeneration effects of cortical, cancellous, and cortico-cancellous human bone substitutes on calvarial defects of rabbits.

Methods

Four 8-mm diameter calvarial defects were created in each of nine New Zealand white rabbits. Freeze-dried cortical bone, freeze-dried cortico-cancellous bone, and demineralized bone matrix with freeze-dried cancellous bone were inserted into the defects, while the non-grafted defect was regarded as the control. After 4, 8, and 12 weeks of healing, the experimental animals were euthanized for specimen preparation. Micro-computed tomography (micro-CT) was performed to calculate the percent bone volume. After histological evaluation, histomorphometric analysis was performed to quantify new bone formation.

Results

In micro-CT evaluation, freeze-dried cortico-cancellous human bone showed the highest percent bone volume value among the experimental groups at week 4. At week 8 and week 12, freeze-dried cortical human bone showed the highest percent bone volume value among the experimental groups. In histologic evaluation, at week 4, freeze-dried cortico-cancellous human bone showed more prominent osteoid tissue than any other group. New bone formation was increased in all of the experimental groups at week 8 and 12. Histomorphometric data showed that freeze-dried cortico-cancellous human bone showed a significantly higher new bone formation percentile value than any other experimental group at week 4. At week 8, freeze-dried cortical human bone showed the highest value, of which a significant difference existed between freeze-dried cortical human bone and demineralized bone matrix with freeze-dried cancellous human bone. At week 12, there were no significant differences among the experimental groups.

Conclusions

Freeze-dried cortico-cancellous human bone showed swift new bone formation at the 4-week healing phase, whereas there was less difference in new bone formation among the experimental groups in the following healing phases.

Modified distal wedge excision for access and treatment of an infrabony pocket in a dog

A six-year-old male neutered Dachshund dog presented with generalized moderate gingivitis and calculus formation. A comprehensive oral examination performed under general anesthesia revealed infrabony pockets and horizontal bone loss associated with the left mandibular first and second molar teeth. The left mandibular second molar tooth was extracted, while the left mandibular first molar tooth was treated by staged periodontal therapy, including a modified distal wedge excision for open root planning and bone augmentation. Preoperative probing depths of 9-mm associated with the distal root of the left mandibular first molar tooth were reduced to 2-mm following treatment. The patient continued to maintain normal periodontal probing depths, with no gingival recession at 3, 6, 16, and 33-months following periodontal treatment.

Placement of implant after bone graft using J block allograft

Securing sufficient alveolar bone is important for a successful implant. Alveolar bone should be augmented to adequate height and width for an implant to satisfy the functional, biological, and aesthetic properties. The subjects of this study were 3 patients with severe bone defects caused by either a periodontal disease or a failure of implants on mandibular posterior tooth, mandibular anterior tooth, and maxillary posterior tooth. The shape of the commercial block allograft (Puros J-Block, Zimmer Dental Inc., Carlsbad, CA) was modified to match the shape of the defect, and resorbable membrane (Puros Pericardium Allograft Membrane, Tutogen Medical GmbH, Germany) was used before suturing the soft tissue. The transplant sites were exposed 4 months later to install the implant. The grafted bone was united with the bone tissue to obtain enough alveolar ridge and to install the implants. Bone allograft used in these cases reduced the need to collect autogenous bone in patients with severe alveolar ridge loss.

Bone replacement grafts for the treatment of periodontal intrabony defects

Bone replacement grafts, including autogenous grafts from intraoral donor sites, allografts, xenografts, and alloplastic bone substitutes, are the most widely used treatment modalities for the regeneration of periodontal osseous defects. Studies suggest a favorable clinical outcome with the use of these materials in terms of improvements in periodontal probing depths, probing attachment gains, and bone fill. In terms of bone fill, most studies report more than 50% resolution of intrabony defects when treated with bone replacement grafts. However, histologic evidence of periodontal regeneration, including new bone, periodontal ligament, and cementum, has been reported only for autogenous bone grafts and demineralized freeze-dried bone allografts.

Effectiveness of proliferating tissues in combination with bovine-derived xenografts to intrabony defects of alveolar bone in dogs

The aim of this study was to investigate the effect of proliferating tissue used in combination with bovine-derived xenograft (BDX) on the formation of new cementum and bone in dogs. Intrabony defects were treated with either BDX in conjunction with autogenous proliferating tissues (BDXplus-proliferating tissues: BDX-P group) or BDX alone (BDX-alone group). The control group received no BDX or proliferating tissues. The animals were sacrificed after 2, 4, and 8 weeks of the treatment, and tissues were histologically examined. Specimens from the control group were characterized by long junctional epithelium and little bone formation. The BDX-P group showed a statistically significant increase in new bone and cementum formation compared to the BDX-alone group (30.9% vs. 18.7, p < 0.01 and 87.8% vs. 61.8, p < 0.01). The ratio of proliferating cell nuclear antigen (PCNA)-positive cells in the newly formed connective tissue of the BDX-P group was significantly greater than that in the BDX-alone group. These findings suggest that the use of proliferating tissues in combination with BDX enhances new bone and cementum formation, offering potential as therapeutic material in periodontal regeneration.

Demineralized freeze-dried bone allograft and platelet-rich plasma vs platelet-rich plasma alone in infrabony defects: a clinical and radiographic evaluation

The objective of this work is to compare the clinical and radiographic outcomes of demineralized freeze-dried bone allograft (DFDBA)/platelet-rich plasma (PRP) combination with PRP alone for the treatment of infrabony defects 18 months after surgery and to examine the influence of radiographic defect angle on the clinical and radiographic outcomes. Twenty-eight infrabony defects were treated with DFDBA/PRP combination or PRP alone. Clinical parameters and radiographic measurements were compared at baseline and 18 months. Interquartile range was performed to classify the defect angles. Mann-Whitney, Wilcoxon test, and Pearson correlation were used to analyze the data. The DFDBA/PRP combination exhibited more favorable gains in both clinical and radiographic parameters than PRP alone group (p < 0.05). A correlation existed between defect angle, defect depth, and clinical/radiographic outcomes for the defects treated with DFDBA/PRP. The narrow defects presented more favorable clinical attachment level values (CAL) gain, probing pocket depth (PPD) reduction and defect resolution than wide defects in the combination group (p < 0.05). The influence of baseline defect angle was not significant in the PRP-alone group (p > 0.05). The results indicate that DFDBA/PRP combination is more effective than PRP alone for the treatment of infrabony defects, and the amount of CAL gain, PPD reduction, and bone fill increases when the infrabony defect is narrow and deep before DFDBA/PRP combination treatment.

Localized ridge augmentation with allogenic block grafts prior to implant placement: case reports and histologic evaluations

The placement of dental implants is based on the amount of alveolar bone present in the edentulous site to be reconstructed. Insufficient alveolar contours may require bone grafting procedures to restore an adequate bone volume before implant placement. Larger osseous defects often require block grafts harvested from the symphysis or the ramus buccal shelf region. These provide adequate donor sites to harvest a graft sufficient to restore a significant defect in the osseous structures planned for implant placements. Autogenous block grafts have been well established to reconstruct these types of defects prior to implant placement procedures. However, surgical complications associated with the unfavorable anatomical structures and the necessity of large donor sites (e.g., symphysis and ramus buccal shelf) have led to the use of allogenic grafting materials. Recent developments in allogenic grafting materials have lead to the development of a corticocancellous block graft harvested from the iliac crest region. This study evaluates the clinical indications of these allogenic graft materials to replace compromised alveolar bone defects both horizontal and vertical in nature. The analysis is supported by re-entry procedures and histologic evaluations to substantiate predictability.

Comparative evaluation of decalcified and non-decalcified freeze-dried bone allografts in rhesus monkeys. I. Histologic findings

BACKGROUND

Controversy exists regarding the relative merits of decalcified (DFDBA) and non-decalcified (FDBA) freeze-dried bone allografts when used in periodontal or other oral surgical procedures.

METHODS

Under typical sedation, six rhesus monkeys had nylon mesh cylinders containing either DFDBA or FDBA implanted into surgically created vertical grooves on the facial aspects of all posterior quadrants. Each quadrant received three cylinders containing one type of bone, plus one empty cylinder (E) as negative control, and the full thickness flaps were closed to completely cover the cylinders. Cylinders were retrieved at 1, 2, and 3 months and processed for histologic evaluation. Photomicrographs taken at 8x were randomly evaluated using a histometric grid point counting technique for new bone and old bone within the chambers, and the data were analyzed with analysis of variance plus post-tests.

RESULTS

The nylon chambers and their contents were well-tolerated by the tissues. FDBA chambers contained more new bone and total bone than either the DFDBA or E chambers at all time periods (P <0.05). DFDBA was not statistically significantly different than E at any time period. FDBA had less old bone than DFDBA at 3 months (P<0.05). FDBA and DFDBA had more total bone (grafted plus new) present than E at all time periods (P<0.05).

CONCLUSION

These results suggest that FDBA may stimulate earlier, more rapid, and more substantial new bone formation than DFDBA in a monkey jaw defect model system.

Evaluation of the adjunctive benefits of platelet-rich plasma in subantral sinus augmentation

Subantral sinus augmentation is often necessary to permit placement of endosseous implants. Recent efforts to improve wound healing have focused on autogenous sources of bioactive mediators, such as platelet-rich plasma (PRP), which offer the potential to enhance the biological activity of bone replacement grafts. The purpose of this randomized, single-blinded, controlled study was to compare bone formation after subantral maxillary sinus augmentation with freeze-dried bone allograft (FDBA) plus PRP versus FDBA plus resorbable membrane. Ten patients underwent bilateral maxillary subantral sinus augmentation, with sites within subjects randomized to receive FDBA plus PRP or FDBA plus membrane. Core biopsy specimens were obtained 4.5 to 6 months after the grafting procedure at time of implant placement. Histomorphometric analysis revealed a significantly higher percentage of vital tissue in sinuses after treatment with FDBA and PRP (78.8 +/- 8.3) than with FDBA and membrane (63.0 +/- 15.7). Moreover, the percentage of bone formation in sinuses augmented with the combination of FDBA plus PRP (33.3 +/- 11.3) was nonsignificantly (P </= 0.10) higher than in sinuses grafted with FDBA plus membrane (26.5 +/- 6.8). Residual graft particles constituted a significantly higher percentage of the regenerate in sinuses treated with FDBA plus membrane than in sinuses augmented with FDBA plus PRP (37.0 +/- 15.7) versus (21.2 +/- 8.3, respectively). When comparing the relative proportion of vital bone to residual graft particles, a significant difference also was observed between sinuses treated with FDBA and membrane compared with sinuses augmented with FDBA and PRP (0.98 +/- 0.77 versus 1.82 +/- 0.88, respectively). The results of this study suggest that the combination of FDBA and PRP enhances the rate of formation of bone compared with FDBA and membrane, when used in subantral sinus augmentation. Future research is needed to determine the clinical significance and the cost- and risk-benefit considerations of the approach.

Maxillary Sinus Augmentation with Platelet-Rich Plasma and Fibrinogen Cryoprecipitate: A Tomographic Pilot Study

The purpose of this study was to evaluate the clinical efficacy of platelet-rich plasma, autologous bone, and autologous fibrinogen as cryoprecipitate in maxillary sinus augmentation procedures. Six patients (age range, 29-58) undergoing sinus augmentation procedures were included in the study. Platelet-rich plasma and autologous fibrinogen in the form of cryoprecipitate were prepared from 300 ml of blood. Sinus augmentation was performed with intraoral bone grafts, platelet-rich plasma, and cryoprecipitate. The amount of regeneration was then evaluated quantitatively and qualitatively with Spiral TC (Dentascan) pre- and postoperatively 6 months after the intervention. Orthopantomography was performed preoperatively 3 and 6 months after the surgery. A mean platelet concentration of 320.5% was obtained from the baseline platelet blood count. The tomographic analysis indicated an average bone augmentation of 6.27 mm (range, 3.5-10 mm). Radiologically, a satisfactory morphological recovery of the maxillary jaw was obtained. No graft resorption was noticed. Orthopantomography indicated mineralization as early as 3 months postoperatively in the entire study population. This technique appeared to be safe and effective. Our preliminary results encourage the clinical use of platelet-rich plasma associated with cryoprecipitate.

Clinical Evaluation of Demineralized Freeze-Dried Bone Allograft and Enamel Matrix Derivative Versus Enamel Matrix Derivative Alone for the Treatment of Periodontal Osseous Defects in Humans

BACKGROUND

A recent study suggests that the addition of enamel matrix derivative to demineralized freeze-dried bone allograft may enhance osseoinduction. The purpose of this study was to evaluate the use of demineralized freeze-dried bone allograft (DFDBA) in combination with enamel matrix derivative (EMD + DFDBA) compared to enamel matrix derivative (EMD) alone in the treatment of human intrabony periodontal defects.

METHODS

Forty patients with a total of 67 sites (intrabony defect > or = 3 mm deep) were selected to participate in this single-masked, parallel design, randomized, controlled clinical trial. Each subject received either EMD alone (34 sites) or in combination with DFDBA (33 sites). Soft tissue measurements included probing depth (PD), clinical attachment level (CAL), and recession. Hard tissue measurements included defect depth, alveolar crestal resorption, and defect morphology. Following 6 months of healing, all soft tissue measurements were repeated. Forty-nine sites (EMD + DFDBA = 26 sites, EMD alone = 23 sites) were surgically reentered. Statistical analyses were performed using unpaired and paired Student t tests.

RESULTS

Analyses showed a significant improvement in soft tissue parameters for both treatment groups (P < 0.001) as compared to preoperative measurements. There were no statistical differences between treatment groups. The probing depth reduction (PDR) for the EMD + DFDBA was 3.6 +/- 0.2 mm, while the EMD alone had a PDR of 4.0 +/- 0.3 mm. The CAL gain for the EMD + DFDBA group was 3.0 +/- 0.3 mm and 3.2 +/- 0.3 mm for the EMD alone group. The mean value for bone fill in the EMD + DFDBA group was 3.7 +/- 0.2 mm (74.9%), while the EMD alone group demonstrated a mean bone fill of 2.6 +/- 0.4 mm (55.3%). While there were no significant differences between the two treatments with regards to soft tissue measurements, the combination of EMD + DFDBA therapy yielded statistically significant improvements in bone fill, crestal resorption, and percentage of sites gaining greater than 50% and 90% bone fill when compared to EMD alone (P < 0.001).

CONCLUSION

The results of this study indicate that there may be an enhancement of hard tissue parameters when enamel matrix derivative is added to demineralized freeze-dried bone allograft.

Osteogenesis in calvarial defects: contribution of the dura, the pericranium, and the surrounding bone in adult versus infant animals

Guided bone regeneration is a promising means for reconstructing bone defects in the cranium. The present study was performed to better define those factors that affect osteogenesis in the cranium. The authors studied a single animal model, investigating the contribution of the dura, the pericranium, and the adjacent calvarial bone in the process of calvarial regeneration in both mature and immature animals. Bilateral, 100-mm2, parietal calvariectomies were performed in immature (n = 16) and mature (n = 16) rabbits. Parietal defects were randomized to one of four groups depending on the differential blockade of the dura and/or the pericranium by expanded polytetrafluoroethylene membranes. Animals were humanely killed after 12 weeks, and histometric analysis was performed to quantitate the area of the original bone defect, new bone formation, and new bone density. Bone formation was quantified separately both at the periphery and in the center of the defects. Extrasite bone formation was also quantified both on the dural and on the pericranial sides of the barriers. Bone regeneration was incomplete in all groups over the 12-week study period, indicating that complete bone healing was not observed in any group. The dura was more osteogenic than the pericranium in mature and immature animals, as there was significantly more extrasite bone formed on the dural side in the double expanded polytetrafluoroethylene barrier groups. In both the dural and the double expanded polytetrafluoroethylene barrier groups, dural bone production was significantly greater in immature compared with mature animals. The dura appeared to be the source of central new bone, because dural blockade in the dural and double expanded polytetrafluoroethylene groups resulted in a significant decrease in central bone density in both mature and immature animals. Paradoxically, isolation of the pericranium in mature animals resulted in a significant reduction in total new bone area, whereas pericranial contact appeared to enhance peripheral new bone formation, with the control group having the greatest total new bone area. The present study establishes a model to quantitatively study the process of bone regeneration in calvarial defects and highlights differences in the contribution of the dura and pericranium to calvarial bone regeneration between infant and adult animals. On the basis of these findings, the authors propose that subsequent studies in which permeability of the expanded polytetrafluoroethylene membranes is altered to permit migration of osteoinductive proteins into the defect while blocking prolapse of adjacent soft tissues may help to make guided bone regeneration a realistic alternative for the repair of cranial defects.

Immediate restoration of multiple tooth implants for aesthetic implant restorations

The immediate restoration or loading of dental implants has been an intense area of clinical trial and research in the field of dental implantology over the last several years. The ability to temporize implants that are placed and prevent the use of a removable transitional appliance is appealing to not only patients, but dentists as well. Additionally, the placement of implants into immediate extraction sockets, and the immediate restoration of those implants, is showing excellent success rates clinically. Enhancement of the healing phase using platelet rich plasma seems to be a key contributor to the healing and maturation rate of both the hard and soft tissues. This article will review the immediate restoration of implants placed into multiple extraction sockets and the use of platelet rich plasma to enhance the healing phase.

Regenerative treatment of serious periodontosis with grafting of cancellous iliac bone and gingival flaps and replanting of patients' teeth

The purpose of this study was to assess the ability of serious periodontosis patients to regain satisfactory biting function, using the patients' own teeth, by regeneration of the alveolar bone. Twelve serious periodontosis patients whose alveolar bone was markedly absorbed and whose teeth were quite unstable were treated with replanting of their teeth and grafting of cancellous iliac bone and gingival flaps by the clinical team, which consisted of plastic surgeons and dentists. No patients developed postoperative complications (e.g., infections), and grafted iliac bone took in all patients. The total number of replanted teeth was 65, and only 4 of them fell off (92% take rate). Three to 4 months after surgery, the replanted teeth received prosthetic treatment so that the patients could begin biting. Ten patients were monitored for 5 months or longer, and they started to eat normal food after the fifth month. Regained biting function and satisfaction of having food were almost the same as before the periodontosis became severe in these 10 patients. Regeneration of alveolar bone was confirmed in later radiographs. To date, the maximum follow-up period is 2 years and 8 months (average = 1 year and 6 months). All patients have good biting function, and there have been no findings of absorption of reconstructed alveolar bone or of the root of replanted teeth. This treatment method would be quite useful for patients with serious periodontosis.

Evaluation of pluronic polyols as carriers for grafting materials: study in rat calvaria defects

BACKGROUND

Pluronic polyols are a family of non-ionic surfactants currently used as drug carriers for antibiotic, anti-inflammatory, and anti-neoplastic agents. Therapeutic administration of non-ionic surface-active agents is known to facilitate early collagen synthesis and microcirculation, thus promoting wound healing. The purpose of this study was to determine the in vivo effects of pluronic polyols combined with either an allograft or an alloplast on the healing of critical-sized calvarial defects.

METHODS

One hundred fifty (150) adult (95 to 105 days old) male Sprague-Dawley rats weighing between 375 and 425 g were randomly and evenly assigned to each of 15 separate treatment groups and anesthetized, and 8 mm calvarial critical-sized defects were created. Pluronic F-68 (F-68) or pluronic F-127 (F-127) was administered either topically or systemically and in conjuction with demineralized bone powder (DBP), tricalcium phosphate (TCP), or non-grafted controls. Pluronic polyols are easily mixed with either DBP or TCP to improve handling ease. Calvaria were harvested at 12 weeks postsurgery and evaluated histomorphometrically, by contact radiography with subsequent densitometric analysis, through energy spectrometry utilizing a scanning electron microscope, and by fluorescent microscopy.

RESULTS

There was a significant difference in the percentage of bone fill among the control, TCP, and DBP only groups, P <0.05. The only significant difference within any of these groups was between the TCP control and TCP plus systemic F-127, P<0.05.

CONCLUSIONS

Although there were isolated differences, the overall trend was that the pluronic polyol and the mode of administration did not result in a significant change in bone wound healing as measured by the percentage of bone fill. Pluronic polyols may be considered as carriers for osseous graft materials.

Alveolar ridge and sinus augmentation utilizing platelet-rich plasma in combination with freeze-dried bone allograft: case series

BACKGROUND

Alveolar bone regeneration is frequently necessary prior to placement of implants. Efforts to improve wound healing have focused on factors that may enhance bone formation following guided bone regeneration (GBR) techniques alone or in combination with bone replacement graft materials. Recent reports suggest that platelet-rich plasma (PRP), presumably high in levels of peptide growth factors, may enhance the formation of new bone when used in combination with autogenous graft material.

METHODS

In this report, the clinical and radiographic results are presented on 15 consecutively treated patients using autologous PRP in combination with freeze-dried bone allograft (FDBA) for sinus elevation and/or ridge augmentation. FDBA and PRP (0.5 g/2cc PRP) were mixed and placed as a composite graft material. A gel formed by mixing autologous thrombin-rich plasma with PRP (1:4 ratio) was used to cover the graft material. Core biopsies of grafted areas were obtained in several patients as part of implant site preparation and were evaluated histologically to determine site maturation.

RESULTS

Of 36 implant fixtures, 32 (89%) were considered clinically successful demonstrating complete bone coverage of the implant, no mobility, and a normal radiographic appearance at the time of re-entry and 12 months post-implant exposure. Four implants were removed due to mobility at the time of surgical exposure. Histologic evaluation of biopsy specimens revealed numerous areas of osteoid and bone formation around FDBA particles, with no evidence of inflammatory cell infiltrate.

CONCLUSIONS

These clinical and histological findings suggest that ridge augmentation and sinus grafting with FDBA in combination with PRP provide a viable therapeutic alternative for implant placements. Future studies are necessary to determine whether PRP enhances new bone formation or maturation with bone replacement allografts.

Augmentation procedures of the jaw in patients with inadequate bone for dental implants: radiographic appearance

Dental implants, metallic posts surgically imbedded in the jaw to support dental prostheses, have provided an attractive alternative to standard removable dentures. Some patients, however, have insufficient bone to accommodate these implants. In this setting, a number of surgical procedures are available to augment the bone in the jaw. It is important for radiologists to be familiar with these procedures because the altered anatomy can be a source of confusion to the unwary. The objective, therefore, was to describe these procedures and their radiographic appearances.

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.

Clinical evaluation of bioactive glass in the treatment of periodontal osseous defects in humans

The purpose of this study was to compare the use of bioactive glass to demineralized freeze-dried bone allograft (DFDBA) in the treatment of human periodontal osseous defects. Fifteen systemically healthy patients (6 males and 9 females, aged 30 to 63) with moderate to advanced adult periodontitis were selected for the study. All patients underwent initial therapy, which included scaling and root planing, oral hygiene instruction, and an occlusal adjustment when indicated, followed by re-evaluation 4 to 6 weeks later. Paired osseous defects in each subject were randomly selected to receive grafts of bioactive glass or DFDBA. Both soft and hard tissue measurements were taken the day of surgery (baseline) and at the 6-month re-entry surgery. The clinical examiner was calibrated and blinded to the surgical procedures, while the surgeon was masked to the clinical measurements. Statistical analysis was performed by using the paired Student's t test. The results indicated that probing depths were reduced by 3.07 +/- 0.80 mm with the bioactive glass and 2.60 +/- 1.40 mm with DFDBA. Sites grafted with bioactive glass resulted in 2.27 +/- 0.88 mm attachment level gain, while sites grafted with DFDBA had a 1.93 +/- 1.33 mm gain in attachment. Bioactive glass sites displayed 0.53 +/- 0.64 mm of crestal resorption and 2.73 mm bone fill. DFDBA-grafted sites experienced 0.80 +/- 0.56 mm of crestal resorption and 2.80 mm defect fill. The use of bioactive glass resulted in 61.8% bone fill and 73.33% defect resolution. DFDBA-grafted defects showed similar results, with 62.5% bone fill and 80.87% defect resolution. Both treatments provided soft and hard tissue improvements when compared to baseline (P < or = 0.0001). No statistical difference was found when comparing bioactive glass to DFDBA; however, studies with larger sample sizes may reveal true differences between the materials. This study suggests that bioactive glass is capable of producing results in the short term (6 months) similar to that of DFDBA when used in moderate to deep intrabony periodontal defects.

Effects of grafting on porous metal ingrowth. A canine model

Twenty-five mongrel dogs were studied using implantation of autograft, fresh-frozen allograft, and beta-tricalcium phosphate around a porous-coated chrome-cobalt plug in the distal femoral metaphysis; interference-fit and overreamed control specimens were also studied. Over the course of this 4-month study, bone ingrowth through the grouting materials into the center plug was noted for autologous, allograft, and ceramic specimens. Quantitatively, in terms of push-out strength and histology, there were no significant differences between grafted groups; significantly higher push-out strengths were attained in each grafted subgroup compared with nongrafted, overreamed control subjects. In the setting of uncemented revision total hip arthroplasty, bone-grafting is frequently required. Because of the limited availability of autogenous bone and the potential liabilities of allograft material, attention has been given to bone substitutes. On the basis of this preliminary study, bone ingrowth into a porous metal substrate has been documented to occur through autograft, allograft, or ceramic grouting agents. Within the limits of this nonloaded experimental model, it appears that these materials are comparable in terms of their osteoconductive capability. Even in the optimal laboratory situation, bone ingrowth does not appear to occur in a canine model across a nongrafted 2-mm gap with regularity over a 16-week period.

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.

Evaluation of guided tissue regeneration in interproximal defects. (II). Membrane and bone versus membrane alone

This study clinically evaluates the use of expanded polytetrafluoroethylene (ePTFE) membranes with or without the addition of decalcified freezedried bone allograft (DFDBA) in the treatment of interproximal intraosseous defects. 25 patients (26 paired defects) diagnosed with advanced periodontitis and having at least 2 bilateral interproximal probing depths of > or = 6 mm participated in the study. After the hygiene phase, measurements were made to determine soft tissue recession, pocket depth, and clinical attachment levels. Defects from each pair were randomly treated with either ePTFE alone (control), or ePTFE+DFDBA (experimental). Measurements were made during the surgery to determine crestal resorption, defect resolution and defect fill. Membranes were removed at 4 to 6 weeks. At 6 months, the soft and hard tissue measurements (surgical reentry) were repeated. Both groups showed statistically significant improvement when compared to baseline (p < 0.001), but no difference was determined between groups. Control sites showed a 50% bone fill and experimental sites had 54% bone fill. The defect resolution changes were also similar between control and experimental groups, respectively (80%, 74%). For this short-term study, it was concluded that either technique was beneficial for the treatment of intraosseous defects. Other studies are needed to assess the long-term stability of the improvements rendered by these treatments.

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.

Fate of demineralized freeze-dried bone allografts in human intrabony defects

Demineralized freeze-dried bone (DFDBA) is the most widely used allograft in periodontics. Little information exists, however, on the fate of DFDBA matrix or on the effects of residual particles within grafted defects. The purpose of this study was to histologically examine the fate of DFDBA used for regeneration in intrabony defects. A secondary objective was to compare the amount of new attachment apparatus formation, including component tissues, in relation to the presence or absence of residual graft material. Histologic data were obtained from earlier studies in which intrabony defects grafted with DFDBA were removed at 6 months en bloc and submitted for histologic examination. Histologic sections (1,120) from 12 patients with 32 grafted defects revealed that 72% of the grafted defects exhibited residual DFDBA particles. When present, DFDBA appeared amalgamated within the new viable bone. Data from 5 patients with 14 grafted sites permitted a within-subject comparison of the amount of regeneration in relation to the presence or absence of residual graft material. Defects harboring residual graft particles exhibited significantly greater amounts of new attachment apparatus formation (1.72 mm vs. 0.20 mm), including new bone (2.33 mm vs. 0.23 mm), cementum (1.74 mm vs. 0.23 mm), and associated periodontal ligament than sites without evidence of graft matrix (P < or = 0.05). No apparent differences were seen in the nature of the new attachment apparatus or component tissues, other than in amount of formation. Inflammation and graft containment appear to be important factors influencing the fate of DFDBA and the regenerative response.

Closure of oroantral communication using guided tissue regeneration and an absorbable gelatin membrane

Surgical intervention into the maxillary posterior area can lead to inadvertent communication with the maxillary sinus. Spontaneous healing of 1 to 2 mm openings can occur. However, in patients with larger oroantral communications and those with a history of sinus disease, surgical closure is often indicated. Acute and chronic oroantral fistula and sinusitis can occur as a result of inadequate treatment. The most common causes of complications include inadequate site preparation, flap closure, flap necrosis, infection, and patient non-compliance. A technique for the closure of oroantral communications using guided tissue regeneration is described. This technique utilizes an absorbable gelatin film (membrane), allogenic bone graft material (DFDBA), and non-resorbable expanded polytetrafluoroethylene (ePTFE) membrane. The gelatin membrane prevents displacement of graft material into the antrum and sinus epithelial cell migration, while the ePTFE membrane promotes selective cell population with subsequent regeneration of the osseous wall of the oroantral defect.

Healing in periodontal defects treated by decalcified freeze-dried bone allografts in combination with ePTFE membranes. Assessment by computerized densitometric analysis

This study quantitatively assessed radiographic changes in alveolar bone density by computer-assisted densitometric image analysis (CADIA) in periodontal defects that were treated with decalcified freeze dried bone allograft (DFDBA) alone or in combination with interproximal expanded polytetrafluroethylene membranes (ePTFE). The radiographic changes where then analyzed for correlation with the clinically assessed changes. The radiographic changes were evaluated on standardized radiographs of treated sites treated prior to, 1 week after surgery, and 6 months post-operatively. 15 patients with one pair of bilateral interproximal periodontal defects of similar morphology and > or = 6 mm in pocket depth participated. Analysis of the changes 6 months after treatment showed that the increases in density in the defect areas that received the graft were significantly greater than the adjacent areas (p < 0.001). These adjacent areas, in contrast, demonstrated significantly larger loss in radiographic density than the defect area (p < 0.001). The placement of DFDBA into the defects produced in itself significant increases in radiographic density, as illustrated by the results of one week which remained at six months. Utilization of ePTFE addition to DFDBA did not lead to additional radiographic gains in the defect area. While at one week the analysis suggested increased resorption by the combined treatment over grafting alone, such differences did not persist at 6 months post-surgery. Analysis comparing CADIA derived values for change with those of the clinical assessment revealed some associations.(ABSTRACT TRUNCATED AT 250 WORDS)

HIV inactivation in a bone allograft

The use of exclusionary techniques in the procurement of donors for bone allografts greatly reduces chances for disease transmission. Furthermore, treatment of HIV with either chemical agents or strong acids will effectively inactivate the AIDS virus. These data are taken as indirect proof that the risk of obtaining AIDS from a freeze-dried bone allograft is highly remote. The purpose of this study is to obtain direct evidence that the processing of a demineralized freeze-dried bone allograft would render the allograft safe for human use. In Part I, human cortical bone was obtained from a cadaveric source and tested to be free of HIV contamination. The bone was spiked with 5.26 x 10(9) viral particles. This corresponded to 148 micrograms of total viral protein. In Part II, cortical bone was procured from a donor who died of AIDS. In both Parts I and II, the cortical bone was ground to yield particle sizes of 90 to 500 microns. Test samples were treated with a virucidal agent and demineralized in HCl. Control samples were left untreated. All samples were cocultivated with stimulated peripheral blood lymphocytes and assayed for p24 core protein, reverse transcriptase, and viral gag gene by polymerase chain reaction (PCR). In Part I, the HIV spiking experiment, untreated virus infected particulate bone was positive for HIV replication. Treated samples were negative when assayed for HIV. Bone samples in Part II, HIV infected bone, were positive by PCR. Replication of viable HIV could not be demonstrated after treatment. It was concluded that demineralization and treatment with a virucidal agent inactivates HIV in spiked and infected bone.

Autogenous and allogeneic bone grafts in periodontal therapy

This article is limited to a review of bone autografts and allografts, as used in periodontal therapy. The various graft materials are discussed with respect to case reports, controlled clinical trials, and human histology. Other reviewed areas are wound healing with periodontal bone grafts, tissue banking and freeze-dried bone allografts, and the use of bone grafts in guided tissue regeneration.