Clinical evaluation of coralline calcium carbonate as a bone replacement graft material in human periodontal osseous defects

Supra-Alveolar Bone Regeneration: Progress, Challenges, and Future Perspectives

Periodontitis is a highly prevalent disease that damages the supporting tissues of a tooth, including the alveolar bone. Alveolar bone loss owing to periodontitis is broadly categorized as supra-alveolar and intra-alveolar bone loss. In intra-alveolar bone loss, the defect has an angular or oblique orientation to the long axis of the tooth in an apical direction. In contrast, the defect is perpendicular to the long axis of the tooth in supra-alveolar bone loss. Unlike intra-alveolar bone defects, supra-alveolar bone defects lack supporting adjacent space, which makes supra-alveolar bone regeneration more challenging. In addition, the limited availability of resources in terms of vascularity and underlying tissues is another obstacle to supra-alveolar bone regeneration. Currently, supra-alveolar bone loss is the least predictable periodontal defect type in regenerative periodontal therapy. In addition, supra-alveolar bone loss is much more common than other alveolar bone loss. Despite its prevalence, research on supra-alveolar bone regeneration remains sparse, indicating an unmet need for significant research efforts in this area. This review summarize recent advances, obstacles, and future directions in the field of supra-alveolar bone regeneration. We discuss the biomaterials, bioactive molecules, and cells that have been tested for supra-alveolar bone regeneration, followed by pre-clinical and clinical approaches employed in this field. Additionally, we highlight obstacles and present future directions that will propel supra-alveolar bone research forward.

Calcium carbonate: Adored and ignored in bioactivity assessment

The title of this article could sound a bit curious to some readers since a layer of apatite - and not calcium carbonate - is well-known to form on the surface of bioactive glasses upon immersion in simulated body fluids. However, calcium carbonate (commonly reported as calcite crystals) can form on the surface of bioactive glasses as well, instead of or in competition with hydroxyapatite, during in vitro tests. Major factors that govern calcium carbonate formation are a high concentration of Ca²⁺ ions in the testing solution - and, in this regard, glass composition/texture and type of medium play key roles - along with the volume of solution used during in vitro tests. To date, this phenomenon has received relatively little attention and is still partly unexplored. This article provides a critical overview of the available literature on this topic in order to stimulate constructive discussion among biomaterials scientists and further research for better understanding the mechanisms involved in glass bioactivity. STATEMENT OF SIGNIFICANCE: A literature search indicates that a layer of apatite - and not calcium carbonate - is well known to form on the surface of biomaterials during the bioactivity assessment. However, calcium carbonate can form on the surface as well, instead of or in competition with apatite. To date, this phenomenon has received relatively little attention and is still partly unexplored. This review provides a critical overview of the available literature on this topic in order to stimulate constructive discussions that can be further useful for clinical success.

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.

Fabrication of calcite blocks from gypsum blocks by compositional transformation based on dissolution-precipitation reactions in sodium carbonate solution

Calcium carbonate (CaCO₃) has been used as a bone substitute, and is a precursor for carbonate apatite, which is also a promising bone substitute. However, limited studies have been reported on the fabrication of artificial calcite blocks. In the present study, cylindrical calcite blocks (ϕ6×3mm) were fabricated by compositional transformation based on dissolution-precipitation reactions using different calcium sulfate blocks as a precursor. In the dissolution-precipitation reactions, both CaSO₄·2H₂O and CaSO₄ transformed into calcite, a polymorph of CaCO₃, while maintaining their macroscopic structure when immersed in 1mol/L Na₂CO₃ solution at 80°C for 1week. The diametral tensile strengths of the calcite blocks formed using CaSO₄·2H₂O and CaSO₄ were 1.0±0.3 and 2.3±0.7MPa, respectively. The fabrication of calcite blocks using CaSO₄·2H₂O and CaSO₄ proposed in this investigation may be a useful method to produce calcite blocks because of the self-setting ability and high temperature stability of gypsum precursors.

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.

Bone Replacement Materials and Techniques Used for Achieving Vertical Alveolar Bone Augmentation

Alveolar bone augmentation in vertical dimension remains the holy grail of periodontal tissue engineering. Successful dental implant placement for restoration of edentulous sites depends on the quality and quantity of alveolar bone available in all spatial dimensions. There are several surgical techniques used alone or in combination with natural or synthetic graft materials to achieve vertical alveolar bone augmentation. While continuously improving surgical techniques combined with the use of auto- or allografts provide the most predictable clinical outcomes, their success often depends on the status of recipient tissues. The morbidity associated with donor sites for auto-grafts makes these techniques less appealing to both patients and clinicians. New developments in material sciences offer a range of synthetic replacements for natural grafts to address the shortcoming of a second surgical site and relatively high resorption rates. This narrative review focuses on existing techniques, natural tissues and synthetic biomaterials commonly used to achieve vertical bone height gain in order to successfully restore edentulous ridges with implant-supported prostheses.

Fabrication of porous calcite using chopped nylon fiber and its evaluation using rats

Although porous calcite has attracted attention as bone substitutes, limited studies have been made so far. In the present study, porous calcite block was fabricated by introducing chopped nylon fiber as porogen. Ca(OH)2 powder containing 10 wt% chopped nylon fiber was compacted at 150 MPa, and sintered to burn out the fiber and to carbonate the Ca(OH)2 under stream of 1:2 O2-CO2. Sintering of Ca(OH)2 at 750 °C or lower temperature resulted in incomplete burning out of the fiber whereas sintering at 800 °C or higher temperature resulted in the formation of CaO due to the thermal decomposition of Ca(OH)2. However, sintering at 770 °C resulted in complete burning out of the fiber and complete carbonation of Ca(OH)2 to calcite without forming CaO. Macro- and micro-porosities of the porous calcite were approximately 23 and 16%, respectively. Diameter of the macropores was approximately 100 μm which is suitable for bone tissue penetration. Porous calcite block fabricated by this method exhibited good tissue response when implanted in the bone defect in femur of 12-weeks-old rat. Four weeks after implantation, bone bonded on the surface of calcite. Furthermore, bone tissue penetrated interior to the macropore at 8 weeks. These results demonstrated the good potential value of porous calcite as artificial bone substitutes.

Effectiveness of synthetic hydroxyapatite versus Persian Gulf coral in an animal model of long bone defect reconstruction

BACKGROUND

There is a continuing search for bone substitutes to avoid or minimize the need for autogenous bone grafts. Hydroxyapatite, a crystalline phase of calcium phosphate found naturally in bone minerals, has shown tremendous promise as a graft material. Coral is an osteoconductive material used as a bone graft extender. This study examined the effect of hydroxyapatite and Persian Gulf coral on osteogenesis in vivo using a rabbit model of bone healing.

MATERIALS AND METHODS

A critical-size defect of 10 mm elongation was created in the radial diaphysis of 36 rabbits and supplied with either hydroxyapatite or coral or left empty (control group). Radiographs of each forelimb were taken postoperatively on day 1 and then at 2, 4, 6, and 8 weeks postinjury to evaluate bone formation, union, and remodeling of the defect. The operated radiuses were removed on the 56th postoperative day and were grossly and histopathologically evaluated. In addition, biomechanical testing was conducted on the operated and normal forelimbs of half of the animals of each group.

RESULTS

In radiological evaluation, bone formation and union were significantly superior in the coral and hydroxyapatite groups in comparison with the control group on the 42nd and 56th day postinjury (P < 0.05). There were no statistical differences between groups in remodeling criteria at the 56th day postinjury (P > 0.05). In histopathological evaluation, the union scores of the rabbits administered hydroxyapatite or coral were statistically superior to those of the animals of the control group on the 56th day postinjury (P < 0.05). In biomechanical evaluation, the control group showed weakness of biomechanical properties in comparison with the coral and hydroxyapatite groups (P < 0.05).

CONCLUSIONS

According to this study, significant difference was not observed between hydroxyapatite and natural coral and these two materials were significantly better than the control group at 8 weeks postinjury.

Histologic and histomorphometric assessment of eggshell-derived bone graft substitutes on bone healing in rats

OBJECTIVE

The objective of this study was to histologically and histomorphometrically evaluate the efficacy of the new formulations of eggshell-derived calcium carbonate in rats.

STUDY DESIGN

The study was conducted on 30 adult male rats. Four standardized and circular intrabony defects were created in the both maxilla and mandibula of each animal. Three different graft materials were prepared as follows: 1) Material A: Eggshell-derived calcium carbonate combined with carrageenan gel, 2) Material B: Eggshell-derived calcium carbonate combined with xanthan gum gel, and 3) Material C: Eggshell-derived calcium carbonate powder. The right mandibular defect sites were grafted with Material A in all animals, and defects on the left were grafted with Material B. Defects on the right side of maxilla were received Material C in all animals, and all left maxillary defects were remained untreated as controls. The animals were sacrificed either postoperatively on the 15th day, postoperatively on the 30th day or postoperatively on the 45th day. Histomorphometric measurements were made of the areas of newly formed bone, necrotic bone, fibrous tissue and residual graft material.

RESULTS

Material A exhibited the highest level of osteoid formation followed by Material B and Material C on the 45th day. In terms of osteoid formation, statistically significant differences were observed between graft materials and controls at 45th day compared to 15th and 30th day (p<0.05).

CONCLUSIONS

Eggshell-derived graft substitutes in both gel and powder forms are biocompatible materials which may have the potential to enhance the new bone formation. Key words:Bone graft material, bone defects, eggshell, histopathological evaluation, rat.

Performance of coralline hydroxyapatite in sinus floor augmentation: a retrospective study

OBJECTIVE

The purpose of this study is to retrospectively explore the utilization of coralline hydroxyapatite in maxillary sinus augmentation.

METHOD

One hundred and eighteen cases of sinus lift with coralline hydroxyapatite (CHA) were included in this study. In detail, simultaneous implantation was conducted in 78 patients (174 implants) and delayed implantation was done in 40 cases (82 implants) around 6 months after bone transplantation. The clinical features and X-ray radiographs after operation were analyzed to evaluate osseointegration procedures according to a planned medical follow-up. In the delayed group, around 6 months, a bone biopsy was taken just during implant placement in order to evaluate the new formed bone from a histological and histomorphometrical point of view. A further 6 months later, abutment connection was performed, and the patients received prosthetic restoration of the missing teeth.

RESULT

Clinically, the incisions healed well. No abnormal reactions were found during follow-up period. All the 174 simultaneous implants were successful after 1-5 years of medical review; Out of 82 delayed implants, 3 were found to be loose. Histologically, all the specimens showed signs of active remodeling, and all the tissues had a large amount of osteocyte at sixth month after sinus augmentation. New bone formed dramatically. Radiologically, the density of CHA gradually reduced since the beginning of the third month, and CHA may be completely resolved at about fifth year.

CONCLUSION

CHA is proven an ideal bone graft material for its reliable clinical results and favorable histocompatibility in the treatment of sinus atrophy or other kinds of insufficient bone volume in this region. Moreover, CHA's signal application can achieve desired clinical effect.

CLINICAL RELEVANCE

This study shows the clinic application of CHA in maxillary sinus augmentation. Compared with popular mixture of autogenous bone and grafting materials, our results show CHA's signal application can achieve ideal osseointegration interface and satisfying clinic effect.

In vivo regenerative properties of coralline-derived (biocoral) scaffold grafts in human maxillary defects: demonstrative and comparative study with Beta-tricalcium phosphate and biphasic calcium phosphate by synchrotron radiation x-ray microtomography

BACKGROUND

In recent years, there has been interest on the fabrication of systems using particulates or block-based approach for bone tissue engineering (TE) scaffolds, possessing porous interconnected structures. In fact, these particular morphologies greatly increase the surface area for more chemical and biological reactions to take place.

PURPOSE

This study was designed to demonstrate the unique capability of the synchrotron radiation x-ray microtomography (micro-CT) in offering an advanced characterization of coralline-derived (Biocoral) biomaterials placed in human maxillary defects as it allows, in a nondestructive way, a complete, precise, and high-resolution three-dimensional analysis of their microstructural parameters. Moreover, the comparison between Biocoral and other biomaterials was explored to understand the mechanism of their biological behavior as bone substitute.

MATERIALS AND METHODS

Implant survival, bone regeneration, graft resorption, neovascularization, and morphometric parameters (including anisotropy and connectivity index of the structures) were evaluated by micro-CT in Biocoral and the other biomaterials after 6 to 7 months from implantation in human maxillary bone defects.

RESULTS

After the in vivo tests, a huge amount of bone was detected in the retrieved Biocoral-based samples, coupled with a good rate of biomaterial resorption and the formation of a homogeneous and rich net of new vessels. The morphometric parameters were comparable to those obtained in the biphasic calcium phosphate-based control, with the exception of the connectivity index for which this control exhibited the most well-connected structure. This last result, together with those referred to the poor performances of the β-tricalcium phosphate block-based sample, suggests that the particular scaffold morphology may play a role in the hunt the optimal scaffold structure to be implanted.

CONCLUSION

In this limited study, implant success rate seems not strictly dependent on the biomaterial that is used, but on the scaffold morphology. Micro-CT technique was demonstrated to play a fundamental role in advanced characterization of bone TE constructs.

Optimization of process parameters of polymer solution mediated growth of calcium carbonate nanoparticles

With the advent of nanotechnology, many methods of synthesis of nanoparticles have come into practice and the 'polymer mediated growth' technique is among them. In this route, ions of one of the reactants are allowed to diffuse from an external solution into a polymer matrix where the other reactant is complexed and bound. The exact role of ionic diffusion in the formation of nanoparticles was investigated in the current study by studying the patterns of kinetics of nanoparticle formation using UV vis spectroscopy. Typically, calcium carbonate nanoparticles were formed by the aforementioned technique using polyethylene glycol solution. The particle size was calculated using Scherrer's formula on x-ray diffraction plots and was reconfirmed with field emission scanning electron microscope and transmission electron microscope images. Energy-dispersive x-ray analysis was used to study the composition and purity of the nanoparticles formed. The reactant to polymer ratio, reaction temperature and molecular weight of polyethylene glycol affected the size of the particles formed. Through this knowledge we optimized these parameters to obtain particles as small as 20 nm and confirmed that this technique can be used to control the size of nanoparticles.

Natural Products: A Minefield of Biomaterials

The development of natural biomaterials is not regarded as a new area of science, but has existed for centuries. The use of natural products as a biomaterial is currently undergoing a renaissance in the biomedical field. The major limitations of natural biomaterials are due to the immunogenic response that can occur following implantation and the lot-to-lot variability in molecular structure associated with animal sourcing. The chemical stability and biocompatibility of natural products in the body greatly accounts for their utilization in recent times. The paper succinctly defines biomaterials in terms of natural products and also that natural products as materials in biomedical fields are considerably versatile and promising. The various types of natural products and forms of biomaterials are highlighted. Three main areas of applications of natural products as materials in medicine are described, namely, wound management products, drug delivery systems, and tissue engineering. This paper presents a brief history of natural products as biomaterials, various types of natural biomaterials, properties, demand and economic importance, and the area of application of natural biomaterials in recent times.

Human platelet rich plasma plus Persian Gulf coral effects on experimental bone healing in rabbit model: radiological, histological, macroscopical and biomechanical evaluation

Coral is an osteoconductive material used as a bone graft extender and human platelet rich plasma has been used as a source of osteoinductive factor. A combination of human platelet rich plasma and coral is expected to create a composite with both osteoconductive and osteoinductive properties. This study examined the effect of a combination of human platelet rich plasma and coral on osteogenesis in vivo using rabbit model of bone healing. A critical size defect of 10 mm elongation was created in the radial diaphysis of 36 rabbit and either supplied with coral-human PRP, or coral alone or left empty (control group). The platelets in the PRP were about 10.1 fold compared to normal blood. Radiographs of each forelimb was taken postoperatively on 1st day and then at the 2nd, 4th, 6th and 8th weeks post injury to evaluate bone formation, union and remodeling of the defect. The operated radiuses were removed on 56th postoperative day and were grossly and histopathologically evaluated. In addition, biomechanical test was conducted on the operated and normal forearms of the rabbits. This study demonstrated that coral-human PRP (hPRP), could promote bone regeneration in critical size defects with a high regenerative capacity. The results of the present study demonstrated that coral-hPRP could be an attractive alternative for reconstruction of the major diaphyseal defects of the long bones in animal models.

Predictability of clinical outcomes following regenerative therapy in intrabony defects

BACKGROUND

Demineralized bone matrix (DBM) and guided tissue regeneration (GTR) support substantial gains in clinical attachment level (CAL), reductions in probing depth (PD), and gains in defect fill compared to open flap debridement (OFD) in intrabony defects. Although these regenerative therapies support improvements in mean clinical parameters, it is unclear whether the procedures improve the predictability of clinical outcome. The purpose of this study was to examine the relative variability in clinical outcome measures, independent of the magnitude of gains, in regenerative studies comparing DBM or GTR to OFD therapy for the management of intrabony defects. For comparative purposes, a similar analysis was performed evaluating the consistency of clinical outcomes with other (non-DBM) bone replacement graft (BRG) materials relative to OFD alone.

METHODS

Fifty-five randomized controlled clinical trials comparing regenerative therapy (seven DBM, 22 BRG, and 26 GTR) to OFD and meeting inclusion criteria provided mean change scores (pretreatment to post-treatment) and variance estimates for CAL, PD, and bone fill, allowing for calculation of a coefficient of variability (CV) for each measure within studies. The mean CV for each measure was submitted to an analysis of variance or covariance with repeated measures (P < or =0.05) to compare relative variation in treatment outcomes.

RESULTS

DBM was associated with a significantly lower relative variability (mean +/- SE) in CAL gain (96.3 +/- 38.6 versus 137.7 +/- 30.9) and defect fill (69.1 +/- 11.2 versus 133.1 +/- 15.3) compared to OFD alone. As a group, other BRGs were found to support significant reductions in variation in CAL and defect fill. GTR therapy was associated with significantly lower CV for CAL compared to OFD (50.6 +/- 5.0 versus 68.7 +/- 8.2, respectively). Variability in defect fill was similar for GTR and OFD.

CONCLUSIONS

DBM and GTR therapy support more consistent improvements in clinical parameters; however, with the exception of defect fill following bone grafting, the reduction in variability in clinical outcomes was relatively modest compared to OFD alone. Overall, the treatment of intrabony defects is associated with a relatively high degree of variability in clinical outcome, regardless of therapeutic approach.

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.

Maxillary sinus augmentation with different biomaterials: a comparative histologic and histomorphometric study in man

OBJECTIVE

Rehabilitation of the edentulous posterior maxilla with dental implants can be difficult because of insufficient bone volume caused by pneumatization of the maxillary sinus and crestal bone resorption. Different biomaterials have been used for sinus augmentation. The aim of the study was to compare different materials in maxillary sinus augmentation in man.

METHODS

A total of 94 patients participated in this study. Inclusion criteria were maxillary partial (unilateral or bilateral) edentulism involving the premolar/molar areas, and the presence of 3-5-mm crestal bone between the sinus floor and alveolar ridge. A total of 362 implants were inserted. There were 9 biomaterials used in the sinus augmentation procedures. Each patient underwent 1 biopsy after 6 months. A total of 144 specimens were retrieved.

RESULTS

None of the 94 patients had complications. All implants were stable, and x-ray examination showed dense bone around the implants. Mean follow-up was 4 years. There were 7 implants that failed. Histologic resultsshowed that almost all the particles of the different biomaterials (i.e., autologous bone, demineralized freeze-dried bone allograft Biocoral [Inoteb, St. Gonnery, France], Bioglass [US Biomaterials, Alachua, FL], Fisiograft [Ghimas, Bologna, Italy], PepGen P-15 [Dentsply Friadent CeraMed, Lakewood, CO], calcium sulfate, Bio-Oss [Geistlich Pharma AG, Wohlhusen, Switzerland], and hydroxyapatite) were surrounded by bone. Some biomaterials were more resorbable than others. Included are the histomorphometry clarified features of the newly formed bone around the different grafted particles.

CONCLUSION

All biomaterials examined resulted in being biocompatible and seemed to improve new bone formation in maxillary sinus lift. No signs of inflammation were present. The data are very encouraging because of the high number of successfully treated patients and the good quality of bone found in the retrieved specimens.

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.

Long-Term Results With Different Bone Substitutes Used for Sinus Floor Elevation

One of the surgical procedures preceding implantation is elevation of the base of the maxillary sinus. Numerous bone substituting materials (grafts) may be used for this purpose, including autogenous bone, heterografts, xenogenous bone, and synthetic materials alone or in combination or mixed with growth factors and bone morphogenetic protein (BMP) preparations. A study of the frequencies of the failures (graft material resorption or implant loss) after sinus elevations with various graft materials or their combinations was conducted. In the 5-year period from 1996 through 2001, a follow-up investigation of 810 maxillary sinus augmentations was performed, in which the sinus elevations involved the use of autogenous bone, a calcium carbonate-coated polymer, hydroxylapatite of algal origin, calcium carbonate gel produced from coral or beta-tricalcium phosphate alone, autogenous bone mixed with these bone substitutes, or a combination of beta-tricalcium phosphate and platelet-rich plasma. The incidences of graft resorption and implant loss after the augmentations with various bone substitutes were recorded. Total resorption (disappearance) of the bone substitute material was observed in 2.7% of the cases. An essential difference was not experienced between the various bone substitutes from this aspect, with the exception of the gel-state calcium carbonate, where 40% of the grafts were resorbed. In total, 5.46% of the implants were lost; the differences between the various materials were not significant.

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 systematic review of graft materials and biological agents for periodontal intraosseous defects

OBJECTIVES

To determine the adjunctive effect of grafting biomaterials/biological agents with open flap debridement (OFD) in the treatment of deep intraosseous defects.

BACKGROUND

No systematic review of treatment outcomes in patients who received graft biomaterials or biological agents have been published.

METHODS

A rigorous systematic review of randomized controlled trials of at least 6-month duration was conducted comparing grafting biomaterials/biological agents (alone or in combination) + OFD (test group) to OFD alone or in combination with a placebo (control group).

RESULTS

The difference in CAL change between test and control groups varied from -1.45 mm to 1.40 mm with respect to different biomaterials/biological agents. Meta-analysis showed that CAL change significantly improved after treatment for coralline calcium carbonate (weighted mean difference 0.90 mm; 95% CI: 0.53-1.27), bioactive glass (weighted mean difference 1.04 mm; 95% CI: 0.31-1.76), hydroxyapatite (weighted mean difference 1.40 mm, 95% CI 0.64-2.16), and enamel matrix proteins (weighted mean difference 1.33 mm, 95% CI 0.78-1.88). However, heterogeneity in results between studies was highly statistically significant for most of biomaterials/biologicals and could not be fully explained.

CONCLUSIONS

Overall, the use of specific biomaterials/biologicals was more effective than OFD in improving attachment levels in intraosseous defects. Difference in CAL gain varied greatly with respect to different biomaterial/biological agent. Due to a significant heterogeneity in results between studies in most treatment groups, general conclusions about the expected clinical benefit of graft biomaterials/biologicals need to be interpreted with caution. Further research should focus on understanding this variability.

Periodontal repair in dogs: a bioabsorbable calcium carbonate coral implant enhances space provision for alveolar bone regeneration in conjunction with guided tissue regeneration

BACKGROUND

Collapse or compression of a barrier device into a periodontal defect or onto the root surface compromises outcomes following guided tissue regeneration (GTR). Bone biomaterials have been suggested to support regeneration of alveolar bone and to improve space provision with GTR devices. The objective of this study was to evaluate space provision, alveolar bone, and cementum regeneration following use of a bioabsorbable, calcium carbonate biomaterial in conjunction with GTR.

METHODS

Routine, critical size, 5 to 6 mm, supraalveolar, periodontal defects were created in 5 young adult beagle dogs. Alternate jaw quadrants in consecutive animals received GTR and the coral biomaterial (cGTR) or GTR alone. The animals were euthanized 4 weeks postsurgery and tissue blocks processed for histometric analysis.

RESULTS

The coral implant particles were surrounded by newly-formed bone or immersed in connective tissue and appeared to resorb and be replaced by bone. There was limited, if any, appreciable cementum regeneration. Space provision was enhanced in cGTR compared to GTR sites (6.1 +/- 1.6 versus 2.4 +/- 0.8 mm2; P<0.05). Bone regeneration (height) was significantly increased in cGTR compared to GTR sites averaging 1.9 +/- 0.6 and 1.2 +/- 0.6 mm, respectively (P<0.05). Bone regeneration (area) was 2-fold greater in cGTR sites compared to the GTR control (3.3 +/- 1.8 versus 1.4 +/- 0.5 mm2), however the difference was not statistically significant (P>0.05).

CONCLUSIONS

The coral implant significantly enhanced space provision for GTR while alveolar bone formation appeared to be enhanced by its use. Increased healing intervals are needed to fully understand the biologic value of the coral implant as an adjunct to GTR.

Scaffolds and biomaterials for tissue engineering: a review of clinical applications

Tissue engineering is a multidisciplinary area of research aimed at regeneration of tissues and restoration of organ function. This is achieved through implantation of cells/tissues grown outside the body or by stimulating cells to grow into an implanted matrix. In this short review, we discuss the use of biomaterials, in the form of scaffolds, for tissue engineering and review clinical applications to otorhinolaryngology-head and neck surgery.

Composite implant of native bovine bone morphogenetic protein (BMP) and biocoral in the treatment of scaphoid nonunions--a preliminary study

BACKGROUND AND AIMS

Bone morphogenetic protein (BMP) has been shown to induce bone formation and union in long bone defects and nonunions. We report a preliminary study of a composite implant consisting of a biocoral frame, carrier collagen and bovine BMP in the treatment of scaphoid nonunions.

MATERIAL AND METHODS

Two proximal and eight waist area scaphoid nonunions were treated using BMP/coral implant combined with either the Matti-Russe procedure (2 cases) or an interpositional bone graft fixed with screws or compression fixation pins (8 cases). In two cases only a one piece BMP/coral implant was used as an interpositional graft and in other cases interpositional autograft was used with granular BMP/coral implant placed between the fragments and the graft.

RESULTS AND CONCLUSIONS

Only two wrists resulted in complete union. These preliminary results suggest that composite implant of BMP, as used in the present study, may not solve the problems encountered in the treatment of scaphoid nonunions. Poor vascular conditions in scaphoid may not provide enough mandatory osteogenic cells for BMP to function properly. In avascular conditions coral does not resorb edequately and implants may also work as a sequester between the bone graft and the scaphoid bone and therefore actually inhibit the healing process.

Thirty-six month follow-up of 25 patients treated with combination anorganic bovine-derived hydroxyapatite matrix (ABM)/cell-binding peptide (P-15) bone replacement grafts in human infrabony defects. I. Clinical findings

BACKGROUND

Long-term evaluation of periodontal therapy is important for clinical decision making.

METHODS

A synthetic cell-binding peptide (P-15) combined with anorganic bovine-derived hydroxyapatite bone matrix (ABM) was evaluated as a bone replacement graft in human periodontal osseous defects. Following initial preparation and reevaluation, flap surgery was performed. A variety of 1-, 2-, 3-wall bony defects were curetted and root surfaces subjected to mechanical debridement only. The bone defects were grafted with ABM/P-15, and the host flaps replaced or slightly coronally positioned. Weekly, then monthly deplaquing was performed until surgical reentry at 6 to 7 months. Patients were then followed on approximate 3-month recalls for 3 years. Twenty-five of the original 31 patients qualified for long-term evaluation in that their ABM/P-15 treated sites did not receive any additional therapy at the time of reentry.

RESULTS

Significant clinical changes for the overall group of bony defects included improvement in mean clinical attachment level from 5.4 mm at surgery to 4.5 mm at the 6-month reentry to 3.8 mm at 3 years. There was also a decrease in mean probing depth from 5.3 mm at surgery to 3.1 mm at the 6-month reentry to 2.9 mm at 3 years. The mean gingival recession changed from +0.1 mm at surgery to 1.4 mm at the 6-month reentry to 0.9 mm at 3 years. All of these differences were at least P <0.05 from surgery to the 6-month reentry, and surgery to 3 years, but were not significant from reentry to 3 years via repeated measures analysis of variance.

CONCLUSIONS

These favorable 3-year results with ABM/P-15 suggest that it may have a beneficial effect in the long-term clinical management of infrabony defects. Further long-term randomized controlled studies are needed to better assess the role of ABM/P-15 in long-term healing of periodontal osseous defects.

Effects of pretreatment clinical parameters on bioactive glass implantation in intrabony periodontal defects

BACKGROUND

The various methods for regeneration of periodontal tissue that have been developed can be classified into guided tissue regeneration and bone implantation. Since the implantation materials have shown both deficiencies and merits, dentists have begun exploring the bioactive glass first used in plastic surgery. This paper examines the effectiveness of this new material on periodontal intrabony defects.

METHODS

Clinical effects of bioactive glass implantation in intrabony periodontal defects were evaluated 6 months after surgery in 38 intrabony defects from 38 patients with chronic periodontitis. Twenty-one experimental defects received bioactive glass implantation (test group), while 17 control defects were treated with a flap procedure only (control group). The criteria for comparative observation were preoperative and postoperative probing depth (PD), clinical attachment level (CAL), bone probing depth (BPD), and gingival recession.

RESULTS

Reductions in PD were observed in both groups (P<0.01). The reduction in PD was significantly greater in the test group when preoperative PD exceeded 7 mm (P<0.01). Improvements in CAL were also observed in both groups (P<0.01), with the test group showing significantly greater gains (P<0.05). In those cases where preoperative CAL was less than 7 mm, there was no statistically significant difference between the two groups. Reduction in BPD was observed in both groups, with the test group showing significantly greater reduction (P <0.01). There was no significant difference in BPD change, however, when preoperative BPD was < or =7 mm. Significantly greater reduction of BPD in the test group was observed when intrabony defect depth was >4 mm (P <0.05). Significant improvements in PD, CAL, and BPD were noted in the test group when the crestal involvement exceeded 100 degrees. Correlation test between various clinical parameters indicated that greater changes in PD and CAL in the test group were observed when preoperative CAL was large (P<0.001), and greater changes in PD (P<0.05), CAL (P<0.01), and BPD (P<0.05) were noted when preoperative BPD was large. Correlation between crestal involvement and CAL change was noted only in the control group (P<0.01). High correlations were observed between PD changes and CAL changes and between CAL changes and BPD changes in both groups.

CONCLUSIONS

Use of a bone substitute in a flap operation resulted in significantly greater improvements in CAL and BPD over flap operation alone and seemed to have positive effects in postoperative PD, CAL, and BPD in those cases with more severe preoperative CAL and BPD.

Bioactive glass granules for regeneration of human periodontal defects

PURPOSE

A comparative study which evaluated the effectiveness of bioactive glass granules of uniform size (300-335 microns) for the regenerative treatment of interproximal intrabony periodontal defects was conducted.

MATERIALS AND METHODS

Twelve pairs of advanced periodontal lesions in 12 patients (6 males and 6 females) were treated in a split-mouth design with open flap débridement in the control sites and open flap débridement with bioactive glass particles placed in the test sites.

RESULTS

At 6 months post-treatment, both treatment modalities demonstrated a gain in clinical attachment level (CAL), with the test sites having a significantly (p < .01) greater gain in CAL than the control sites. Reentry procedures were performed to assess the amount of hard tissue fill. The test sites demonstrated significantly (p < .001) more gain in hard tissue fill than the controls.

Multi-center clinical comparison of combination anorganic bovine-derived hydroxyapatite matrix (ABM)/cell binding peptide (P-15) and ABM in human periodontal osseous defects. 6-month results

BACKGROUND

Intraosseous periodontal defects present a particular treatment problem. New bone replacement grafts offer promise for improved results.

METHODS

The role of a synthetic cell-binding peptide (P-15), combined with anorganic [corrected] bovine-derived hydroxyapatite bone matrix (ABM), was compared to ABM alone in human periodontal osseous defects in a controlled, monitored, multi-center trial. Following appropriate initial preparation procedures, flap surgery with defect and root debridement was performed. Two osseous defects per patient were treated randomly with each procedure after surgical preparation. Appropriate periodontal maintenance schedules were followed, and at 6 to 7 months, re-entry flap surgery was performed for documentation and finalization of treatment.

RESULTS

T test and Mann-Whitney U analyses of patient mean values from 33 patients revealed that the combination ABM/P-15 grafts demonstrated significantly better mean defect fill of 2.9 +/- 1.2 mm (72.9%) versus a mean defect fill of 2.2 +/- 1.4 mm (50.67%) for defects treated with ABM (P<0.05). Other hard tissue findings showed similar clinically superior results with the use of ABM/P-15. Relative defect fill results showed 81% positive (50% to 100% defect fill) responses with ABM/P-15 and 67% positive responses with ABM. There were 3.5 times as many optimal results (> or = 90% defect fill) with ABM/P-15 and twice as many failures (minimal response) with ABM. Soft tissue findings showed no significant differences between treatments.

CONCLUSIONS

These results suggest that the use of the P-15 synthetic cell-binding peptide combined with ABM yields better clinical results than the ABM alone in intrabony periodontal defects.

Tissue-engineered bone regeneration

Bone lesions above a critical size become scarred rather than regenerated, leading to nonunion. We have attempted to obtain a greater degree of regeneration by using a resorbable scaffold with regeneration-competent cells to recreate an embryonic environment in injured adult tissues, and thus improve clinical outcome. We have used a combination of a coral scaffold with in vitro-expanded marrow stromal cells (MSC) to increase osteogenesis more than that obtained with the scaffold alone or the scaffold plus fresh bone marrow. The efficiency of the various combinations was assessed in a large segmental defect model in sheep. The tissue-engineered artificial bone underwent morphogenesis leading to complete recorticalization and the formation of a medullary canal with mature lamellar cortical bone in the most favorable cases. Clinical union never occurred when the defects were left empty or filled with the scaffold alone. In contrast, clinical union was obtained in three out of seven operated limbs when the defects were filled with the tissue-engineered bone.

Addition of fibrin sealant to ceramic promotes bone repair: long-term study in rabbit femoral defect model

Despite their impact on the healing of soft connective tissue, fibrin sealants have not been shown conclusively to have an important role in the healing of bone defects. We report the positive influence of fibrin sealants on repair of cancellous bone cavities filled with a porous, resorbable ceramic. We studied two fibrin sealants: Autocolle and Tissucol. Autocolle is enriched in platelet factors during its preparation. Tissucol is a commercially available fibrin glue prepared from pooled human plasma that has no enrichment in platelet factors. Cavities 10 mm in depth and 5 mm in diameter were drilled in lateral condyles of 45 New Zealand rabbits. These defects were filled with either coral granules or a mixture of fibrin sealant (Autocolle or Tissucol) and coral granules or left empty. At 1 month addition of a fibrin sealant (Autocolle or Tissucol) to the coral led to a significant increase in bone formation in comparison to coral alone. At 2 months significant fibrin sealant mediated enhancement of bone repair was observed with Autocolle only. At 6 months bone formation was similar to the adult bone amount in nonoperated animals, whatever the initial material. Control cavities, on the other hand, were invaded with fibrous tissue only at each time period.

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.

A 5-year follow-up of 16 patients treated with coralline calcium carbonate (BIOCORAL) bone replacement grafts in infrabony defects

A resorbable coralline calcium carbonate graft material (BIOCORAL) (CalCarb) was evaluated as a bone replacement graft in human periodontal osseous defects. Following initial preparation and re-evaluation, flap surgery was carried out. Bone defects were curetted and root surfaces subjected to mechanical debridement and conditioning with tetracycline paste. The bone defects were grafted with CalCarb, and the host flaps replaced or slightly coronally positioned. Weekly, then monthly deplaquing was performed until surgical reentry at 6-12 months. Patients were then followed on approximate 3 month recalls for > or =5 years. Significant clinical changes included improvement in mean vertical clinical probing attachment level from 5.7 mm at surgery to 4.2 mm at re-entry to 4.0 mm at 5 years, decrease in mean probing pocket depth from 6.1 mm at surgery to 3.0 mm at re-entry to 3.3 mm at 5 years, and mean gingival recession from +0.4 mm at surgery to 1.0 mm at re-entry to 0.7 mm at 5 years (all at least p<0.05 from surgery to re-entry and surgery to 5 years, N.S. from reentry to 5 years via ANOVA). These favorable long-term results with CalCarb suggest that CalCarb may have a beneficial effect in the long-term clinical management of infrabony defects.

Periodontal repair in intrabony defects treated with a calcium sulfate implant and calcium sulfate barrier

THIS RANDOMIZED, CONTROLLED, CLINICAL STUDY was designed to evaluate outcome following surgical implantation of an allogeneic, freeze-dried, demineralized bone matrix-calcium sulfate (DBM+CS) composite with a CS barrier in intrabony periodontal defects. Twenty-six patients contributing 26 deep intrabony defects completed the study. Thirteen patients received the DBM+CS implant. Thirteen patients received gingival flap surgery alone (GFS; control). Clinical outcome was assessed at 6 and 12 months postsurgery. At 12 months postsurgery, probing depth (PD) reduction (mean +/-SD) for the DBM+CS and GFS group was to 4.3+/-0.5 and 3.0+/-1.3 mm; clinical attachment gain was to 2.9+/-0.8 and 1.7+/-1.5 mm; and probing bone level gain was to 2.9+/-1.4 and 1.2+/-1.2 mm, respectively. There were no apparent differences between evaluations at 6 and 12 months postsurgery. Clinical improvements were significantly different from presurgery for both groups at both observation intervals (P < 0.01). There were no significant differences between groups in PD reduction and clinical attachment gain. Probing bone level gain was significantly greater in the DBM+CS group compared to controls (P < 0.05). In summary, surgical implantation of DBM+CS with a CS barrier resulted in reduced PD and improved attachment levels comparable to that achieved by gingival flap surgery alone. However, gain in probing bone levels in deep intrabony periodontal pockets assessed by clinical parameters was greater than that observed by gingival flap surgery alone. These changes were noted at both 6 and 12 months after surgery. This regenerative technique needs further biologic evaluation before being generally accepted.

Generalizability of the added benefits of guided tissue regeneration in the treatment of deep intrabony defects. Evaluation in a multi-center randomized controlled clinical trial

BACKGROUND

Several studies have shown that GTR therapy of intrabony defects results in significantly better outcomes than access flap alone. Most of the available data, however, have been produced in highly controlled research environments by a small group of investigators. Generalizability of results to different clinicians and different subject populations has not been evaluated so far.

METHODS

This parallel group study involved 143 patients recruited in a practice-based research network of 11 offices in 7 countries. It was designed to evaluate: 1) the applicability of the documented added benefits of GTR in the treatment of intrabony defects to different populations, and 2) the generalizability of the expected results to different clinicians. GTR was compared to access flap alone. Defects, one in each patient, were accessed with a previously described papilla preservation flap in both the test and control group. In addition, GTR sites received application of a bioabsorbable poly-D,L-lactide-co-glycolide membrane. A stringent plaque control regimen was enforced in all patients during the 1-year observation period. Outcomes included gains in clinical attachment (CAL) and reductions in probing depth.

RESULTS

Observed gains in CAL were 2.18 +/- 1.46 mm for access flap and 3.04 +/- 1.64 mm for the GTR-treated group. The treatment-associated difference was statistically significant (P = 0.03) after correcting for both center effect and defect anatomy. Among the various centers, a 1.73 mm difference in CAL gain was observed. This is a clinically relevant amount, which underlines the significance of center variability in the outcome of periodontal surgical procedures. A frequency distribution analysis of the obtained CAL gains indicated that GTR treatment of deep intrabony defects decreased, with respect to the access flap control, the probability of obtaining only a modest attachment gain at 1 year. Conversely, CAL gains of 4 mm or more were observed in more than 40% of GTR-treated defects and in less than 20% of the controls (P < 0.0001).

CONCLUSIONS

These data indicate that GTR therapy of deep intrabony defects performed by different clinicians on various patient populations resulted in both greater amounts and improved predictability of CAL gains than access flap alone.

Evaluation of proliferation and protein expression of human bone marrow cells cultured on coral crystallized in the aragonite of calcite form

The two crystalline forms of CaCO3, aragonite (from natural coral) and calcite (from natural limestone), have been used with success as bone graft substitutes. However, natural coral transformed into calcite by heating has never been tested. The objective of this work was to study the proliferation and alkaline phosphatase, osteonectin, and osteocalcin expression of human bone marrow cells cultured on CaCO3 crystallized both in the aragonite form (natural coral) and in the calcite form (natural coral modified by heating). The methods used to characterize calcite obtained from the coral were volumic porosimetry, scanning electron microscopy (SEM) and X-ray diffraction. Cell colonization of the material was assessed by SEM performed on days 1, 7, 20, and 30 and [3H]thymidine incorporation was performed on days 3, 7, 12, 18, 25, and 32. Phenotypic expression was assessed by using in situ cytochemistry (alkaline phosphatase), immunocytochemistry (osteonectin and osteocalcin), and hybridization (osteocalcin, beta-actin, and alkaline phosphatase mRNA). Results showed the transformation of aragonite into calcite after heating, the conservation of macroporosity, and a modification of the surface. Calcite appeared to have a smoother and more uniform surface than aragonite crystals. As for [3H]thymidine there was an increase incorporation from days 3 to 18, a stabilization from days 18 to 25, and a decrease from days 25 to 32. After 20 days of culture, immunological studies using monoclonal antibodies to osteocalcin, osteonectin, cytochemical analysis of alkaline phosphatase activity, and in situ hybridization using osteocalcin, beta-actin, and alkaline phosphatase cDNA indicated that the cells had not lost their osteoblastic phenotype. These experiments demonstrate that coral crystallized in the aragonite or calcite form present a similar degree of specific cytocompatibility.

Multi-center clinical evaluation of combination anorganic bovine-derived hydroxyapatite matrix (ABM)/cell binding peptide (P-15) as a bone replacement graft material in human periodontal osseous defects. 6-month results

A synthetic cell-binding peptide (P-15) combined with anorganic bovine-derived hydroxyapatite bone matrix (ABM) was compared to demineralized freeze-dried bone allograft (DFDBA) and open flap debridement (DEBR) in human periodontal osseous defects in a controlled, monitored, multi-center trial. Following appropriate initial preparation procedures, flap surgery with defect and root debridement was performed. Three osseous defects per patient were treated randomly with one of three procedures after surgical preparation. Appropriate periodontal maintenance schedules were followed, and at 6 to 7 months re-entry flap surgery was performed for documentation and finalization of treatment. Analysis of variation (ANOVA) and t test analyses of patient mean values from 31 patients revealed that the combination ABM/P-15 grafts demonstrated significantly better mean defect fill of 2.8 +/- 1.2 mm (72.3%) versus a mean defect fill of 2.0 +/- 1.4 mm (51.4%) for defects treated with DFDBA (P <0.05) and a mean defect fill of 1.5 +/- 1.3 mm (40.3%) (P <0.05) for defects treated with DEBR. Other hard tissue findings showed similar clinically superior results with the use of ABM/P-15. Relative defect fill results showed 87% positive (50% to 100% defect fill) responses with ABM/P-15, 58% positive responses with DFDBA, and 41% positive responses with DEBR. There were 8 to 9 times more failures (minimal response) with DFDBA and DEBR (26% to 29% frequency) than with ABM/P-15. Soft tissue findings showed no significant differences among treatments except for greater clinical attachment level gain with ABM/P-15 compared to DEBR. These results suggest that the use of the P-15 synthetic cell-binding peptide combined with ABM yields better clinical results than either DFDBA or DEBR. Further studies are needed to determine the relative roles of the ABM and/or the P-15 in these improved results.

Comparison of bioactive glass synthetic bone graft particles and open debridement in the treatment of human periodontal defects. A clinical study

The purpose of this study was to compare the repair response of bioactive glass synthetic bone graft particles and open debridement in the treatment of human periodontal osseous defects. Fifty-nine defects in 16 healthy adults were selected. Each patient had at least 2 sites with attachment loss of at least 6 mm with clinical and radiographic evidence of intrabony or furcation defects. One to 3 months after cause-related therapy (oral hygiene instructions, scaling and root planing), the following measurements were recorded prior to surgery: probing depths, clinical attachment level, and gingival recession. Each defect was surgically exposed and measurements made of the alveolar crest height and base of osseous defect. The test defects were implanted with bioactive glass. The other sites served as unimplanted controls. Flaps were sutured at or close to the presurgical level. Radiographs and soft tissue presurgical measurements were repeated at 6, 9, and 12 months. At 12 months all sites were surgically re-entered to record osseous measurements. At the 12-month evaluation, significantly greater mean probing depth reduction was noted in the bioactive glass group compared to the controls (4.26 mm versus 3.44 mm; P = 0.028). Clinical attachment level gain was significantly improved (P = 0.0004) in the bioactive glass sites (2.96 mm) compared to the control sites (1.54 mm). There was significantly less gingival recession in the bioactive glass sites (1.29 mm) compared to the control sites (1.87 mm). Defect fill was significantly greater in the bioactive glass sites (3.28 mm) compared to the control sites (1.45 mm). Defect depth reduction was significantly greater in the bioactive glass sites (4.36 mm) compared to the control sites (3.15 mm). In conclusion, bioactive glass showed significant improvement in clinical parameters compared to open flap debridement.

"In vitro" dissolution of coral in peritoneal or fibroblast cell cultures

Previous studies have shown that in vivo coral resorption involves a biphasic process: First, the edges of the coral block become powdery, then extracellular fluid and phagocytosis contribute to the dissolution of the crystals. The authors examined some types of cells that could be involved in phagocytosis, particularly the ability of both dermal fibroblasts and mouse-resident peritoneal cells to phagocytose and dissolve coral powder "in vitro". Radioactive coral was incubated for 24, 48, or 72 hrs with cells in the presence or absence of cytochalasin B (a phagocytic inhibitor) or chloroquine (a lysosomotropic agent). Furthermore, to specify the role of crystal cell contacts in the solubilization process, they incubated radioactive coral in conditioned media (obtained from two-day human fibroblastic or macrophagic cell culture in the presence or absence of non-radioactive coral) or at a distance from the cells using culture inserts. Measurements of the radioactivity in the different supernatants were performed. Transmission electron microscopy was carried out on the cells cultivated in the presence or absence of radioactive coral. The data suggest that both fibroblasts and macrophages dissolve the coral, and that the intracellular degradation in phagolysosomes is one of the mechanisms explaining coral powder dissolution.

Particulate bioglass as a grafting material in the treatment of periodontal intrabony defects

The present clinical trial was designed to evaluate the effects of a bioactive glass, Perioglas, in the treatment of periodontal intrabony defects. 20 patients, 23-55 years of age (44 sites), with intrabony defects completed the 1-year study. Teeth with furcation involvement were excluded. After completion of initial therapy, defects were randomly assigned to either a test or control procedure. Following flap reflection, root planing and removal of chronic inflammatory tissue in both groups, the test defects were restored with the bioactive glass particulate material. Mucoperiosteal flaps were replaced, sutured and a periodontal dressing was used. All the patients received postoperative antibiotics and analgesics and were seen at 1 week for suture removal. Follow-up was then carried out weekly and at 3 months, 6 months, 9 months and 1 year post-surgery. Plaque score, bleeding score, probing pocket depth (PPD), probing attachment level (PAL) and gingival recession were recorded at baseline, 3 months and 1 year. Standardised radiographs for computer-assisted densitometric image analysis (CADIA) were taken at baseline, immediately post-operatively and at 1 year. The CADIA data showed a significant increase (F-ratio: 15.67, p < 0.001) in radiographic density and volume between the defects treated with the Perioglas when compared to those treated with surgical debridement only. PPD and PAL showed significant improvements in both experimental and control sites, with a greater trend to improvement in the experimental sites. It was concluded that this bioactive glass is effective as an adjunct to conventional surgery in the treatment of intrabony defects.

Long-term results of hydroxyapatite-fibrin glue implantation in plastic and reconstructive craniofacial surgery

The bone tissue formed in orthotopic or heterotopic implants of granular, porous hydroxyapatite and fibrin glue was examined several (2 1/2-8) years after implantation. The results showed distinct ossification in all cases and the functional situation and external appearance were also satisfactory. The reconstituted spongy and compact bone underwent a remodelling process similar to that of normal bone. Most of the hydroxyapatite granules were embedded in the bone tissue; a few were very close to the fibrillar connective tissue of the intertrabecular spaces and were either covered by osteoid-like collagenous borders or were in contact with osteoclast-like giant cells. Even if the results refer only to a few patients, and were obtained from a cross-sectional study, they allow the conclusion to be reached that the implantation of porous hydroxyapatite and fibrin glue leads to the formation of long-lasting bone whose hardness is equal to, or greater than, that of normal bone.