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PubMed1987

Coralline porous hydroxylapatite as a bone graft substitute in orthognathic surgery.

This prospective study was undertaken to evaluate the use of coralline porous hydroxylapatite as a bone graft substitute in orthognathic surgery. Ninety-two consecutive patients received a total of 355 block implants to the maxilla (294), mandible (41), and midface (20). There were 202 implants positioned directly adjacent to the maxillary sinus. Complications were minimal, the most common being exposure of the implant to the oral or nasal cavity. Histologic evaluation of implants that were biopsied in nine patients, four to 16 months postsurgery, revealed connective tissue ingrowth throughout the implants with approximately one-third being bone of variable maturity and two-thirds being soft tissue.

Adolescent↗
PubMed1997

[Hydroxyapatite ceramics in clinical application. Histological findings in 23 patients].

Based on the histological findings of 23 patients who had received implants of the bovine hydroxyapatite ceramic Endobon for a period of up to 16 months, the biocompatibility, nature and extent of osseointegration as well as the resorption and degradation behaviour of the ceramic were investigated. The investigation material consisted mainly of small fragments that had been retrieved during revision operations that were indicated for other reasons. The results confirm the good tolerability and suitability that have been systematically investigated in experimental studies and described for hydroxyapatite ceramic as bone substitute in a vital cancellous bone bed that is not exposed to excessive strain (due to its brittle character). The importance of fulfilling certain requirements in order to achieve a successful result, such as stable implantation in a well vascularized, infection-free bone bed also with a minimization of the contact with local connective tissue has been further substantiated. Good success has been achieved by simultaneous loading with autogenous bone marrow as is practised by many ceramic users. In some cases a widening of intergrain boundaries as well as partial dissociation of superficial hydroxyapatite crystallites were observed in the implant surface.

Adolescent↗
PubMed1997

The biological effect of natural bone mineral on bone neoformation on the rabbit skull.

The aim of this study was to evaluate the effect of deproteinized bovine bone graft material on new bone formation in a guided bone regeneration model system. In 20 rabbits, a periosteal skin flap was raised uncovering the calvaria. A form stable hemispherical dome made of poly-lactic acid (PLA) was placed onto the roughened calvaria. Prior to placement, the dome was either filled with peripheral blood alone (control group, 8 rabbits), or with blood and OsteoGraf/N-300 (test group, 12 rabbits). The wound was closed for primary healing. Morphometric assessment of 1- and 2-month undecalcified histologic specimens revealed better tissue fill in the test domes at 1 month (test 99%, control 55%) (P < 0.05) and 2 months (t, 100%; c, 82%). The fraction of the new bone within the regenerated tissue was higher in the test specimens at 1 month (t, 22%; c, 12%) (P < 0.05) and 2 months (t, 34%; c, 24%). The fraction of the entire space underneath the domes occupied by bone was higher in the test at 1 month, but higher in the controls at 2 months. The fraction of the bone substitute material in contact with bone increased from 1 month (34% +/- 14) to 2 months (45% +/- 5). The surface fraction of osteoblast layers was tendentially higher in the test at 1 month but higher in the control specimens at 2 months. In both test and control, initially woven bone was formed which underwent subsequent remodeling. Cellular degradation of the deproteinized bone graft was frequently detected. It is concluded that deproteinized bovine bone mineral has osteoconductive properties and can initially accelerate new bone formation during guided bone regeneration by increased recruitment of osteoblasts.

Animals↗
PubMed2002

[A clinical and histological study of Bio-Oss in combination with guided bone regeneration membrane technique].

OBJECTIVE: To evaluate the reliability of Bio-Oss particles as bone grafts in combination with membrane-technique. METHODS: 6 small biopsy specimens were retrieved without causing iatrogenic damage in 6 patients (implant sites). The Donath's hard tissue section and micro grinding technique was adopted, and Leval Laczko staining method was used. RESULTS: The histological results showed Bio-Oss particles were easily distinguished from the newly formed bone, but new bone was formed among different particles of Bio-Oss, no connective tissue was found. Intimate contact between newly formed bone and particles of the graft was present. CONCLUSIONS: Bio-Oss appears to be highly biocompatible and osteoconductive. It can be used success fully as a bone substitute in combination with guided bone regeneration membrane technique.

Adult↗
PubMed2006

Sinus graft with biogran, autogenous bone, and PRP: a report of three cases with histology and micro-CT.

Three sinuses were grafted with a bioactive glass bone substitute (Biogran) mixed with autogenous bone retrieved from intraoral donor sites. In two of the three sinuses a platelet-rich plasma (PRP) gel was added to the graft. Bone biopsies retrieved after 5, 6, and 15 months were analyzed. Micro-computerized tomography (micro-CT) values of total bone volume/total volume (TBV/TV) were very reliable compared to histomorphometry. Biogran mixed with autogenous bone and PRP seems to have a positive effect in sinus grafting, with TBV/TV values ranging between 40% and 68%. Micro-CT results have never been compared with histomorphometry for the evaluation of grafted biomaterials. Micro-CT evaluation of some morphometric parameters was difficult, because the radiodensities of Biogran and a certain grade of bone mineralization were similar.

Biocompatible Materials↗
PubMed2001

Guided tissue regeneration for periodontal infra-bony defects.

BACKGROUND: Conventional treatment of destructive periodontal (gum) disease arrests the disease but does not regain the bone support or connective tissue lost in the disease process. Guided tissue regeneration (GTR) is a surgical procedure that aims to regenerate the periodontal tissues when the disease is advanced and could overcome some of the limitations of conventional therapy. OBJECTIVES: To assess the efficacy of GTR in the treatment of periodontal infra-bony defects measured against the current standard of surgical periodontal treatment, open flap debridement. SEARCH STRATEGY: We conducted an electronic search of the Cochrane Oral Health Group specialised trials register and MEDLINE up to October 2000. Hand searching included Journal of Periodontology, Journal of Clinical Periodontology, Journal of Periodontal Research and bibliographies of all relevant papers and review articles up to October 2000. In addition, we contacted experts/groups/companies involved in surgical research to find other trials or unpublished material or to clarify ambiguous or missing data and posted requests for data on two periodontal electronic discussion groups. SELECTION CRITERIA: Randomised, controlled trials of at least 12 months duration comparing guided tissue regeneration (with or without graft materials) with open flap debridement for the treatment of periodontal infra-bony defects. Furcation involvements and studies specifically treating early onset diseases were excluded. DATA COLLECTION AND ANALYSIS: Screening of possible studies was conducted independently by two reviewers (RT & IN) and data abstraction by three reviewers (RT, IN & EGL). The methodological quality of studies was assessed in duplicate (RT & IN) using both individual components and a quality scale (Jadad 1998) and agreement determined by Kappa scores. Methodological quality was used in sensitivity analyses to test the robustness of the conclusions. The Cochrane Oral Health Group statistical guidelines were followed (HW) and the results expressed as weighted mean differences (WMD and 95% CI) for continuous outcomes and relative risk (RR and 95% CI) for dichotomous outcomes calculated using random effects models where significant heterogeneity was detected (P < 0.1). The final analysis was conducted using STATA 6 in order to combine both parallel group studies and intra-individual (split-mouth) studies. The primary outcome measure was gain in clinical attachment. Any heterogeneity was investigated. MAIN RESULTS: We initially included 23 trial reports. Twelve were subsequently excluded. Of these, seven presented six-months data only, three were not fully randomised controlled trials, one used a non-comparable radiographic technique. Eleven studies were finally included in the review, ten testing GTR alone and two testing GTR+bone substitutes (one study had both test treatment arms). For attachment level change, the weighted mean difference between GTR alone and open flap debridement was 1.11 mm (95% CI: 0.63 to 1.59), chi-square for heterogeneity 31.4 (df = 9), p<0.001) and for GTR+bone substitutes was 1.25 mm (95% CI: 0.89 to 1.61, chi-square for heterogeneity 0.01 (df = 1), p=0.91). GTR showed a significant benefit when comparing the numbers of sites failing to gain 2 mm attachment, with relative risk 0.58 (95% CI: 0.38, 0.88, chi-square for heterogeneity 5.72 (df = 3), p=0.13). The number needed to treat (NNT) for GTR to achieve one extra site gaining 2 mm or more attachment over open flap debridement was 8 (95% CI: 4, 33), based on an incidence of 32% of sites in the control group failing to gain 2 mm or more of attachment. For baseline incidences in the range of the control groups of 10% and 55% the NNTs are 24 and 3. Probing depth reduction demonstrated a small but statistically significant benefit for GTR, weighted mean difference 0.80 mm (95% CI: 0.14,1.46, chi-square for heterogeneity 10.0 (df = 4), p=0.04) or GTR+bone substitutes, weighted mean difference 1.24 mm (95% CI: 0.89, 1.59, chi-square for heterogeneity 0.03 (df = 1), p=0.85). No significant difference was noted for gingival recession between GTR and open flap debridement. Regarding hard tissue probing at surgical re-entry, a statistically significant greater gain was found for GTR compared with open flap debridement. This amounted to a weighted mean difference of 1.39 mm (95% CI: 1.08, 1.71, chi-square for heterogeneity 0.85 (df = 2), p=0.65). For GTR+bone substitutes the difference was greater, with mean difference 3.37 mm (95% CI: 3.14, 3.61). Heterogeneity between studies was highly statistically significant for all principal comparisons and could not be explained satisfactorily by sensitivity analyses. The quality of study reporting was poor with seven out of 11 studies graded as poor using the Jadad score. (ABSTRACT TRUNCATED)

Alveolar Bone Loss↗
PubMed1992

The influence of testosterone substitution on bone mineral density in patients with Klinefelter's syndrome.

The aim of this study was to clarify the extent of bone mineral deficiency in patients with Klinefelter's syndrome on the premise that testosterone substitution could prevent this deficiency. Bone mineral density was measured by single-photon absorptiometry in 42 patients with Klinefelter's syndrome, (21 patients without therapy, 10 with testosterone substitution before the age of 20 and 11 patients with testosterone substitution beginning after the age of 20). We found significantly lower bone mineral density in patients without therapy and in patients when the therapy began later compared to normal individuals. Patients with early therapy showed a high proportion of normal values of bone mineral density. We found a positive correlation between bone mineral density and plasma testosterone and a negative correlation between plasma testosterone and age for patients without therapy. These findings suggest that low testosterone levels before or during puberty cause inadequate bone development and low bone mineral density in Klinefelter's syndrome. Only early testosterone substitution may prevent bone mineral deficiency. Later substitution no longer affects bone mineral density.

Adult↗
PubMed2005

Bone regeneration in osseous defects using a resorbable nanoparticular hydroxyapatite.

PURPOSE: This animal study examined the de novo bone formation in bony defects following the insertion of autogenous bone alone versus an injectable nanoparticle hydroxyapatite alone and in combination with 25% autogenous bone. The regenerative potentials of the tested materials were compared with each other. MATERIALS AND METHODS: A model with biological similarity to humans with regard to bone regeneration was a prerequisite for the transferability of the results to clinical practice. Therefore, the adult domestic pig was the animal of choice. A total observation period of 6 months was selected. Microradiographic and histologic evaluation of the bone specimens was completed at 8 defined times. RESULTS: Microradiography indicated mineralization rates in the 2 bone substitute groups that were not significantly lower than those found in the autogenous bone group. Histologically, there was suitable osseointegration and osteoconduction of the used material. Complete resorption of the nanoparticle hydroxyapatite had taken place after 12 weeks. CONCLUSIONS: It can be concluded that the evaluated nanoparticular hydroxyapatite met the clinical requirements for a bone substitute material within the limits of this experimental setting. Due to its microstructure, complete resorption took place during the course of this study.

Absorbable Implants↗
PubMed2006

Guided tissue regeneration for periodontal infra-bony defects.

BACKGROUND: Conventional treatment of destructive periodontal (gum) disease arrests the disease but does not usually regain the bone support or connective tissue lost in the disease process. Guided tissue regeneration (GTR) is a surgical procedure that specifically aims to regenerate the periodontal tissues when the disease is advanced and could overcome some of the limitations of conventional therapy. OBJECTIVES: To assess the efficacy of GTR in the treatment of periodontal infra-bony defects measured against conventional surgery (open flap debridement (OFD)) and factors affecting outcomes. SEARCH STRATEGY: We conducted an electronic search of the Cochrane Oral Health Group Trials Register, MEDLINE and EMBASE up to April 2004. Handsearching included Journal of Periodontology, Journal of Clinical Periodontology, Journal of Periodontal Research and bibliographies of all relevant papers and review articles up to April 2004. In addition, we contacted experts/groups/companies involved in surgical research to find other trials or unpublished material or to clarify ambiguous or missing data and posted requests for data on two periodontal electronic discussion groups. SELECTION CRITERIA: Randomised, controlled trials (RCTs) of at least 12 months duration comparing guided tissue regeneration (with or without graft materials) with open flap debridement for the treatment of periodontal infra-bony defects. Furcation involvements and studies specifically treating aggressive periodontitis were excluded. DATA COLLECTION AND ANALYSIS: Screening of possible studies and data extraction was conducted independently. The methodological quality of studies was assessed in duplicate using individual components and agreement determined by Kappa scores. Methodological quality was used in sensitivity analyses to test the robustness of the conclusions. The Cochrane Oral Health Group statistical guidelines were followed and the results expressed as mean differences (MD and 95% CI) for continuous outcomes and risk ratios (RR and 95% CI) for dichotomous outcomes calculated using random-effects models. Any heterogeneity was investigated. The primary outcome measure was change in clinical attachment. MAIN RESULTS: The search produced 626 titles, of these 596 were clearly not relevant to the review. The full text of 32 studies of possible relevance was obtained and 15 studies were excluded. Therefore 17 RCTs were included in this review, 16 studies testing GTR alone and two testing GTR+bone substitutes (one study had both test treatment arms).No tooth loss was reported in any study although these data are incomplete where patient follow up was not complete. For attachment level change, the mean difference between GTR and OFD was 1.22 mm (95% CI Random Effects: 0.80 to 1.64, chi squared for heterogeneity 69.1 (df = 15), P < 0.001, I(2) = 78%) and for GTR + bone substitutes was 1.25 mm (95% CI 0.89 to 1.61, chi squared for heterogeneity 0.01 (df = 1), P = 0.91). GTR showed a significant benefit when comparing the numbers of sites failing to gain 2 mm attachment with risk ratio 0.54 (95% CI Random Effects: 0.31 to 0.96, chi squared for heterogeneity 8.9 (df = 5), P = 0.11). The number needed to treat (NNT) for GTR to achieve one extra site gaining 2 mm or more attachment over open flap debridement was therefore 8 (95% CI 5 to 33), based on an incidence of 28% of sites in the control group failing to gain 2 mm or more of attachment. For baseline incidences in the range of the control groups of 3% and 55% the NNTs are 71 and 4. Probing depth reduction was greater for GTR than OFD: 1.21 mm (95% CI 0.53 to 1.88, chi squared for heterogeneity 62.9 (df = 10), P < 0.001, I(2) = 84%) or GTR + bone substitutes, weighted mean difference 1.24 mm (95% CI 0.89 to 1.59, chi squared for heterogeneity 0.03 (df = 1), P = 0.85). For gingival recession, a statistically significant difference between GTR and open flap debridement controls was evident (mean difference 0.26 mm (95% CI Random Effects: 0.08, 0.43, chi squared for heterogeneity 2.7 (df = 8), P = 0.95), with a greater change in recession from baseline for the control group. Regarding hard tissue probing at surgical re-entry, a statistically significant greater gain was found for GTR compared with open flap debridement. This amounted to a weighted mean difference of 1.39 mm (95% CI 1.08 to 1.71, chi squared for heterogeneity 0.85 (df = 2), P = 0.65). For GTR + bone substitutes the difference was greater, with mean difference 3.37 mm (95% CI 3.14 to 3.61). Adverse effects were generally minor although with an increased treatment time for GTR. Exposure of the barrier membrane was frequently reported with a lack of evidence of an effect on healing. AUTHORS' CONCLUSIONS: GTR has a greater effect on probing measures of periodontal treatment than open flap debridement, including improved attachment gain, reduced pocket depth, less increase in gingival recession and more gain in hard tissue probing at re-entry surgery. However there is marked variability between studies and the clinical relevance of these changes is unknown. As a result, it is difficult to draw general conclusions about the clinical benefit of GTR. Whilst there is evidence that GTR can demonstrate a significant improvement over conventional open flap surgery, the factors affecting outcomes are unclear from the literature and these might include study conduct issues such as bias. Therefore, patients and health professionals need to consider the predictability of the technique compared with other methods of treatment before making final decisions on use. Since trial reports were often incomplete, we recommend that future trials should follow the CONSORT statement both in their conduct and reporting. There is therefore little value in future research repeating simple, small efficacy studies. The priority should be to identify factors associated with improved outcomes as well as investigating outcomes relevant to patients. Types of research might include large observational studies to generate hypotheses for testing in clinical trials, qualitative studies on patient-centred outcomes and trials exploring innovative analytic methods such as multilevel modelling. Open flap surgery should remain the control comparison in these studies.

Alveolar Bone Loss↗
PubMed2001

Repairing segmental bone defects with living porous ceramic cylinders: an experimental study in dog femora.

Twenty-one porous hydroxyapatite-tricalcium phosphate ceramic cylinders 1.5 cm long and 1.2 cm in diameter were swathed with fresh autogenetic periostea taken from 21 dogs and implanted in the same animals' muscles to get living ceramic bone substitutes. These substitutes contained autogenetic growth stimulators including osteoblasts and other multipotential cells. One month later, they were transferred to the segmental bone defect sites created in femoral diaphysis of the same animals. The roentgenograms showed that in time the boundaries between the cylinders and bone sections became vague. X-ray diffraction analysis indicated that the spectra of the samples tended to be similar to those of natural bones by 6 months postoperatively. Their bending strengths also increased gradually. After the cylinders were transferred from muscles to the bone defect sites, newly formed bone tissues rapidly increased and the cylinders gradually fused with the contacted bones 2 months later. By 4 and 6 months, bone tissue occupied most areas of the materials. The ratio of newly formed bone tissue had a large lead over the materials. Haversian systems were clearly observed and matured bone tissues filled the ceramic pores and connected with each other. Results suggested that culturing complexes that consist of autogenetic periostea and biomaterials, taking advantage of living organic culturing medium, should be an effective approach to get satisfactory bioactive bone substitutes. It also provides a basis for clinically repairing bone defects in bearing sites with complex bioceramics.

Animals↗
PubMed1997

[IGF-I mRNA expression level of cell in the interfaces of bone and four kinds of substitutive materials for bone tissues by the technique in situ hybridization].

Four kinds of substitutive materials for hard tissues were inserted into tibias of rat, effect of substitutive materials on IGF-I mRNA expression level of cell in the interfaces of bone and four kinds of substitutive materials were studied by the technique in situ hybridization. It showed that the biomaterials could affect the level of IGF-I mRNA expression, the enhanced expression level was associated with cell proliferation, formation of matrix and calcification, formation of new bone. Measurement of IGF-I mRNA could attribute to judge the functional state of cell, and to predict the final character of the interface.

Animals↗
PubMed1991

Multicenter trial of Collagraft as bone graft substitute.

Collagraft (Zimmer and Collagen Corporation) consists of a mixture of porous beads composed of 60% hydroxyapatite and 40% tricalcium phosphate ceramic and fibrillar collagen. When mixed with autogenous bone marrow, it serves as an effective bone graft substitute. Since September 1986, this material has been used in a multiclinic prospective trial, randomized against cancellous iliac crest autografts in the treatment of long bone fractures. To date, 267 patients have entered this study with 128 patients receiving cancellous autograft and 139 patients receiving Collagraft. At 6- and 12-month follow-ups, Collagraft appears to function as well as autogenous graft when used in the treatment of acute long bone fractures.

Adolescent↗
PubMed1989

Porous, block hydroxyapatite as an interpositional bone graft substitute in orthognathic surgery.

Forty-six nonconsecutive patients undergoing orthognathic surgery in whom blocks of coralline, porous hydroxyapatite (Interpore-200) were used in lieu of interpositional bone grafts are the subjects of this report. Surgical procedures included inferior repositioning of the maxilla (7) and chin (12), maxillary advancements in cleft (4) and noncleft individuals (13), and transverse maxillary expansions (12). Patients included in this study were only those in whom bone grafts would have been harvested had hydroxyapatite not been available. A total of 93 anatomic sites were implanted. The complication rate attributable to the use of the implant was 4.3 percent. Follow-up period ranged from 6 to 20 months, with a mean of 9.3 months. At this time, osseous stability was confirmed cephalometrically in all but two patients undergoing maxillary expansions. The biologic behavior and mechanical properties of coralline-derived, porous, block hydroxyapatite are discussed. These implant characteristics make it a feasible bone graft substitute for interpositional use in orthognathic surgery. Proper indications for its use as well as technical details to minimize complications are stressed.

Adolescent↗
PubMed2006

P-15 small peptide bone graft substitute in the treatment of non-unions and delayed union. A pilot clinical trial.

Treatment of non-unions and delayed unions often requires osteogenic material. Recently, a biomimetic bone matrix that simulates the cellular environment of hard tissue, identified as P-15, was introduced to the orthopaedic community. A total of 22 patients with mal-union or delayed union fractures was treated from June 2000 to October 2003 with P15- bone graft substitute (P15-BGS) in the site of fracture and mostly with internal fixation. Patients were examined by independent radiographic analysis. Assessment criteria included time elapsed until bone bridging and time to full consolidation. In addition, histological assessment of the callus was done at the time of recovery of metal implants in five patients. Full consolidation was achieved in 90% (20 out of 22) of the patients treated with P15-BGS. The average time for full consolidation was 4.2 months. Histological assessment of the fracture callus in five of the patients confirmed the positive clinical and radiographic results. P15-BGS appears to offer a safe, economical and clinically useful alternative to autograft in the repair of ununited fractures. These results compare favourably with those in the published literature as an alternative to autograft.

Adolescent↗
PubMed2003

Results of curettage and high-speed burring for chondroblastoma of the bone.

BACKGROUND: Chondroblastomas of the bone are rare lesions. Most of these lesions can be successfully treated by curettage and bone grafting. However, a considerable rate of recurrence has been reported, especially in aggressive lesions. The purpose of this study was to report the results of 10 cases of chondroblastomas of the bone treated with curettage and high-speed burring. METHODS: Ten patients with histologically confirmed chondroblastoma of the bone were treated with curettage and high-speed burring between October 1991 and August 2000. There were 7 men and 3 women with an average age of 18.9 (range, 12 to 30) years. Radiographically, 3 were classified as having aggressive lesions, and 7 were classified as having non-aggressive ones. For treatment, 8 of them had defects packed with either bone grafts or bone substitutes; 1 defect was packed with bone cement; and the other was left alone because the lesion was small. RESULTS: At an average follow-up period of 62 (range, 8 to 112) months, all patients had painless, normal function of the affected limb without local recurrence or distant metastasis. Complete healing of the lesion was seen in 8 patients including the one without a bone graft. The lesion in 1 patient who had received bone cement remained unchanged radiographically. One patient experienced incomplete healing of the lesion, which was caused by inadequate packing of the bone substitute. CONCLUSION: Curettage and high-speed burring represent an effective method for the treatment of chondroblastoma of the bone whether in the non-aggressive or aggressive stage.

Adolescent↗
PubMed1989

[Coral substituted for bone grafting in posterior vertebral arthrodesis in children. Initial results].

The authors used natural coral as a substitutive element to bone supply in children in need of posterior vertebral graft. The use of natural coral was part of a protocol aiming at diminishing peroperative bleeding, and as far as possible, at doing away with resorting to homotransfusion. After reviewing the biological, experimental and clinical bases, the authors studied 49 cases of posterior vertebral fusion instrumented with the Cotrel-Dubousset device and with natural coral grafts. Results were appraised with X-ray in all cases, 5 times with scintigraphies and 7 times with biopsies and were encouraging: coral behaves quite similarly to the usual bone graft. From their experience the authors describe how coral is to be used and consider that the use of this substitutive element should spread in the future under various forms.

Animals↗
PubMed1998

The effects of guided bone regeneration and grafting on implants placed into immediate extraction sockets. An experimental study in dogs.

Guided bone regeneration (gbr) for the treatment of insufficient bone volume around implants can be performed using membranes with or without grafting materials (i.e., autogenous, allogenous, xenogenous, or alloplastic grafts). A possible way to evaluate the quality of implant osseointegration is the torque necessary to remove implants from their bony housing. The aim of this study was to compare the torques necessary to remove dental implants from implant beds reconstructed with different bone substitutes and GBR or GBR alone in 6 adult mongrel dogs. All mandibular premolars were extracted and 3 extraction sockets on each side were enlarged using a trephine bur. A 13 mm titanium screw-type dental implant (3.75 mm diameter) was placed in each enlarged extraction socket so that only the apical 3 to 4 mm were engaged in bone. The 3 defects were then randomly treated with either 1) canine demineralized freeze-dried bone allograft (DFDBA) plus GBR using an expanded polytetrafluoroethylene membrane (DFDBA+GTAM); 2) bioabsorbable hydroxyapatite and GBR (HA+GTAM); or 3) GBR (GTAM alone). After 6 months, the torque to remove the implants was measured in 4 animals and analyzed using ANOVA. There were no statistically significant differences between the 3 groups (GTAM alone: 46.37+/-16.41 Ncm; HA+GTAM: 46.00+/-16.59 Ncm; DFDBA+ GTAM: 52.15+/-29.24 Ncm). In addition, the influence of early removal of barriers on the torque values was evaluated with the t-test. Comparing exposed versus retained membranes by treatment modality, the only statistically significant difference was found in the DFDBA+GTAM group. When the torque values of all implants with exposed and retrieved membranes were compared to all those with retained membranes a significant difference could be detected. Histologic sections were prepared from the 2 dogs not included in the removal torque testing. In the histometric analysis the GTAM alone group showed a mean mineralized bone-to-implant-contact of 27.1%, the DFDBA+GTAM group of 34.6%, and the HA+GTAM of 39.3%. The mineralized bone-to-implant-contact of the HA+GTAM group was significantly higher than that of the GTAM alone group. In addition, the mineralized bone-to-implant-contact was divided into an apical and coronal part using the apical seventh thread as the dividing landmark. In the apical region, there was no significant difference between the groups regarding mineralized bone-to-implant-contact. In the coronal part the mineralized bone-to-implant-contact of the GTAM alone group was significantly lower compared to the other 2 groups. Within the limits of this investigation, it can be concluded that the type of grafting material will not influence torque removal values, but that early membrane exposure and removal will negatively influence the torque measurements. The combination of GBR with a bone substitute increased the mineralized bone-to-implant contact.

Absorbable Implants↗
PubMed2002

Applications of a new carbonated calcium phosphate bone cement: early experience in pediatric and adult craniofacial reconstruction.

Hydroxyapatite cements have recently been employed as bone substitutes in craniofacial reconstruction. They are easily applied, nonresorbable, available in unlimited quantity, and eliminate donor-site morbidity. Norian CRS (craniofacial repair system) is a new carbonated calcium phosphate paste that is unique in that it more closely resembles bone than do traditional hydroxyapatite pastes. Norian is a low-order crystalline apatite soluble at a low pH, facilitating its resorption and replacement by host bone. The cement was first used for craniofacial surgery in North America at the Children's Hospital of Philadelphia. This report presents the authors' experience with this bone substitute in both pediatric and adult craniofacial reconstruction. Sixteen adult and pediatric patients underwent craniofacial reconstruction involving the use of carbonated calcium phosphate paste for correction of defects that required from 5 to 110 g of carbonated calcium phosphate paste (mean, 28.5 g). The patients were all followed for a minimum of 14 months. Minor complications included one case of infection and two cases involving cement microfragmentation. In the authors' experience, carbonated calcium phosphate paste has proved to be an excellent alloplastic material for osseous augmentation and reconstruction in the craniofacial skeleton. Few problems were encountered using this material; no significant morbidity was encountered. Although this material seems to be promising as a bone substitute, further follow-up will be necessary to evaluate its potential role in craniofacial surgery.

Adolescent↗