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Grafting Material (grafting + material)

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Medical Sciences	89%

Selected Abstracts

Bone regeneration in rabbit sinus lifting associated with bovine BMP

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2004
Sergio Allegrini Jr.
Abstract Autogenous bone is considered the optimal grafting material for sinus lifting, although its harvesting causes great patient discomfort. Various approaches have been taken in order to obtain sinus lifting with preexisting tissue. However, because of the unsuitability of such tissue, additional materials have been required. Alternatively, biomaterials from humans or other animals are used. In this study, the efficacy of using morphogenetic bovine bone protein (BMPb) to augment the maxillary sinus floor was examined. Four grafting materials were employed: lyophilized bovine bone powder, absorbable collagen flakes, natural hydroxylapatite, and synthetic hydroxylapatite. Two groups of rabbits were studied. In one group, graft material only was used. In the other, graft material was combined with 0.5 mg BMPb. During 8 weeks of observation, polyfluorochrome tracers were injected in subcutaneous tissue to evaluate new bone- deposition periods. Following sacrifice, the samples were examined under fluorescent and light microscopes. Results indicated 33.34% more newly formed bone in BMPb animals than in controls. Graft-material resorption increased, but natural HA showed no significant alterations. The results show that the use of BMPb, although providing osteoinduction, might not promote sufficient bone formation. Nonetheless, this material could provide an alternative to autogenous grafts, thereby avoiding patient discomfort. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 127,131, 2004 [source]

Immediate single-tooth implants in the anterior maxilla: a 1-year case cohort study on hard and soft tissue response

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 7 2008
Tim De Rouck
Abstract Aim: The objective of the present study was to assess implant survival rate, hard and soft tissue response and aesthetic outcome 1 year after immediate placement and provisionalization of single-tooth implants in the pre-maxilla. All patients underwent the same strategy, that is mucoperiosteal flap elevation, immediate implant placement, insertion of a grafting material between the implant and the socket wall and the connection of a screw-retained provisional restoration. Material and Methods: Thirty consecutive patients were treated for single-tooth replacement in the aesthetic zone by means of immediate implant placement and provisionalization. Reasons for tooth loss included caries, periodontitis or trauma. At 6 months, provisional crowns were replaced by the permanent ones. Clinical and radiographic evaluation was completed at 1, 3, 6 and 12 months to assess implant survival and complications, hard and soft tissue parameters and patient's aesthetic satisfaction. Results: One implant had failed at 1 month of follow-up, resulting in an implant survival rate of 97%. Radiographic examination yielded 0.98 mm mesial, respectively, 0.78 mm distal bone loss. Midfacial soft tissue recession and mesial/distal papilla shrinkage were 0.53, 0.41and 0.31 mm, respectively. Patient's aesthetic satisfaction was 93%. Conclusions: The preliminary results suggest that the proposed strategy can be considered to be a valuable treatment option in well-selected patients. [source]

Mesenchymal stem cells and platelet-rich plasma enhance bone formation in sinus grafting: a histomorphometric study in minipigs

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2008
Francesco Pieri
Abstract Objectives: Autologous, allogenic, and alloplastic materials for sinus augmentation have specific drawbacks, which has stimulated an ongoing search for new materials and tissue-engineering constructs. We investigated whether mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) seeded on a fluorohydroxyapatite (FH) scaffold can improve bone formation and bone-to-implant contact (BIC) in maxillary sinus grafting. Material and Methods: Bilateral sinus augmentation procedures were performed in eight minipigs. MSCs, PRP, and FH scaffold (test site) or FH alone (control site) were grafted in each maxillary sinus. Distal to the osteotomy, one dental implant per sinus was placed in the grafting material through the facial sinus wall. The animals were killed 3 months after grafting, and block sections of the implant sites were harvested and prepared for histomorphometric analysis. Results: After 12 weeks, a significant increase in bone formation occurred in the test sites compared with the control sites (42.51%versus 18.98%; p=0.001). In addition, BIC was significantly greater in the test sites compared with the control sites in the regenerated area (23.71%versus 6.63%; p=0.028). Conclusions: These findings show that sinus augmentation with MSCs,PRP, combined with FH may enhance bone formation and osseointegration of dental implants compared with FH alone in minipigs. [source]

Histological evaluation on bone regeneration of dental implant placement sites grafted with a self-setting ,-tricalcium phosphate cement

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2008
Masayoshi Nakadate
Abstract This study aimed to evaluate the histological characteristics of the new bone formed at dental implant placement sites concomitantly grafted with a self-setting tricalcium phosphate cement (BIOPEX-R®). Standardized defects were created adjacent to the implants in maxillae of 4-week-old male Wistar rats, and were concomitantly filled with BIOPEX-R®. Osteogenesis was examined in two sites of extreme clinical relevance: (1) the BIOPEX-R®-grafted surface corresponding to the previous alveolar ridge (alveolar ridge area), and (2) the interface between the grafting material and implants (interface area). At the alveolar ridge area, many tartrate-resistant acid phosphatase (TRAPase)-reactive osteoclasts had accumulated on the BIOPEX-R® surface and were shown to migrate toward the implant. After that, alkaline phosphatase (ALPase)-positive osteoblasts deposited new bone matrix, demonstrating their coupling with osteoclasts. On the other hand, the interface area showed several osteoclasts initially invading the narrow gap between the implant and graft material. Again, ALPase-positive osteoblasts were shown to couple with osteoclasts, having deposited new bone matrix after bone resorption. Transmission electron microscopic observations revealed direct contact between the implant and the new bone at the interface area, although few thin cells could still be identified. At both the alveolar ridge and the interface areas, newly formed bone resembled compact bone histologically. Also, concentrations of Ca, P, and Mg were much alike with those of the preexistent cortical bone. In summary, when dental implant placement and grafting with BIOPEX-R® are done concomitantly, the result is a new bone that resembles compact bone, an ideal achievement in reconstructive procedures for dental implantology. Microsc. Res. Tech., 2008. © 2007 Wiley-Liss, Inc. [source]

The Acetabular Reamer: A Unique Tool for Anterior Iliac Crest Bone Graft Harvesting

THE LARYNGOSCOPE, Issue 3 2005
David G. Gossman MD
Abstract Bone grafting is often required in craniofacial reconstruction. Morselized corticocancellous bone grafts are particularly useful in applications such as filling and contouring irregular bony defects. Obtaining grafts of this consistency by traditional methods is difficult. An efficient harvesting method that can produce such grafting material in clinically useful quantities is needed. We report the use of a mechanical acetabular reamer for the purpose of harvesting a bone graft from the iliac crest. [source]

Alveolar ridge preservation with guided bone regeneration and a synthetic bone substitute or a bovine-derived xenograft: a randomized, controlled clinical trial

CLINICAL ORAL IMPLANTS RESEARCH, Issue 7 2010
Nikos Mardas
Abstract Objectives: The aim of this randomized, controlled clinical trial was to compare the potential of a synthetic bone substitute or a bovine-derived xenograft combined with a collagen membrane to preserve the alveolar ridge dimensions following tooth extraction. Methods: Twenty-seven patients were randomized into two treatment groups following single tooth extraction in the incisor, canine and premolar area. In the test group, the alveolar socket was grafted with Straumann Bone Ceramic® (SBC), while in the control group, Bio-Oss® deproteinized bovine bone mineral (DBBM) was applied. In both groups, a collagen barrier was used to cover the grafting material. Complete soft tissue coverage of the barriers was not achieved. After 8 months, during re-entry procedures and before implant placement, the horizontal and vertical dimensions of the residual ridge were re-evaluated and trephine biopsies were performed for histological analysis in all patients. Results: Twenty-six patients completed the study. The bucco-lingual dimension of the alveolar ridge decreased by 1.1±1 mm in the SBC group and by 2.1±1 in the DBBM group (P<0.05). Both materials preserved the mesio-distal bone height of the ridge. No differences in the width of buccal and palatal bone plate were observed between the two groups. The histological analysis showed new bone formation in the apical part of the biopsies, which, in some instances, was in direct contact with both SBC and DBBM particles. The coronal part of the biopsies was occupied by a dense fibrous connective tissue surrounding the SBC and DBBM particles. Conclusion: Both biomaterials partially preserved the width and the interproximal bone height of the alveolar ridge. To cite this article: Mardas N, Chadha V, Donos N. Alveolar ridge preservation with guided bone regeneration and a synthetic bone substitute or a bovine-derived xenograft: a randomized, controlled clinical trial. Clin. Oral Impl. Res. 21, 2010; 688,698. [source]

Maxillary sinus floor elevation using the (transalveolar) osteotome technique with or without grafting material.

CLINICAL ORAL IMPLANTS RESEARCH, Issue 7 2009
Part I: implant survival, patients' perception
Abstract Objectives: To analyze the survival and success rates of implants installed utilizing the (transalveolar) osteotome technique, to compare peri-implant soft tissue parameters and marginal bone levels of osteotome-installed implants with implants placed using standard surgical procedures, and to evaluate patient-centered outcomes. Material and methods: During 2000 to 2005, 252 Straumann® dental implants were inserted in 181 patients. The surgical technique was a modification of the original osteotome technique presented by Summers. In addition to the clinical examination, the patients were asked to give their perception of the surgical procedure, utilizing a visual analogue scale. Results: The cumulative survival rate of the osteotome-installed implants after a mean follow-up time of 3.2 years, was 97.4% (95% confidence intervals: 94.4,98.8%). From the 252 implants inserted, three were lost before loading and another three were lost in the first and second year. According to residual bone height the survival was 91.3% for implant sites with ,4 mm residual bone height, and 90% for sites with 4 mm and 5 mm, when compared with that of 100% in sites with bone height of above 5 mm. According to implant length the survival rates were 100% for 12 mm, 98.7% for 10 mm, 98.7% for 8 mm and only 47.6% for 6 mm implants. Soft tissue parameters (pocket probing depth, probing attachment level, bleeding on probing and marginal bone levels) did not yield any differences between the osteotome-installed and the conventionally placed implants. More than 90% of the patients were satisfied with the implant therapy and would undergo similar therapy again if necessary. The cost associated with implant therapy was considered to be justified. Conclusion: In conclusion, the osteotome technique was a reliable method for implant insertion in the posterior maxilla, especially at sites with 5 mm or more of preoperative residual bone height and a relatively flat sinus floor. [source]

Immunohistochemical characterization of guided bone regeneration at a dehiscence-type defect using different barrier membranes: an experimental study in dogs

CLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2008
Frank Schwarz
Abstract Objectives: The aim of the present study was to evaluate immunohistochemically the pattern of guided bone regeneration (GBR) using different types of barrier membranes. Material and methods: Standardized buccal dehiscence defects were surgically created following implant bed preparation in 12 beagle dogs. Defects were randomly assigned to six different GBR procedures: a collagen-coated bone grafting material (BOC) in combination with either a native, three cross-linked, a titanium-reinforced collagen membrane, or expanded polytetrafluorethylene (ePTFE), or BOC alone. After 1, 2, 4, 6, 9, and 12 weeks of submerged healing, dissected blocks were processed for immunohistochemical (osteocalcin , OC, transglutaminase II , angiogenesis) and histomorphometrical analysis [e.g., bone-to-implant contact (BIC), area of new bone fill (BF)]. Results: In general, angiogenesis, OC antigen reactivity, and new bone formation mainly arose from open bone marrow spaces at the bottom of the defect and invaded the dehiscence areas along the implant surface and BOC. At 4 weeks, membranes supporting an early transmembraneous angiogenesis also exhibited some localized peripheral areas of new bone formation. However, significantly increasing BIC and BF values over time were observed in all groups. Membrane exposure after 10,12 weeks was associated with a loss of the supporting alveolar bone in the ePTFE group. Conclusion: Within the limits of the present study, it was concluded that (i) angiogenesis plays a crucial role in GBR and (ii) all membranes investigated supported bone regeneration on an equivalent level. [source]

Osteotome sinus floor elevation without grafting material: a 1-year prospective pilot study with ITI implants

CLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2006
Rabah Nedir
Abstract Objective: The aim of the present pilot study was to evaluate: (1) the predictability of an osteotome sinus floor elevation procedure with ITI-SLA implants without placing a bone grafting material, and (2) the possibility to gain bone height without filling the created space with a bone grafting material. Material and methods: Seventeen patients received 25 implants protruding in the sinus. Most implants (21/25) were 10 mm long, eight were inserted in type 2 bone, 12 in type 3 and five in type 4 bone. At implant placement, the mean residual bone height (RBH) under the maxillary sinus was 5.4±2.3 mm; it was 5.7±2.6 mm on the mesial side and 5.1±1.9 mm on the distal side. Nineteen implants had less than 6 mm of bone on at least one side and six implants had less than 6 mm on both sides. A healing period of 3,4 months was allowed before abutment tightening at 35 Ncm. The percentage of stable implants at abutment tightening and at the 1-year control was calculated. The endo-sinus bone gain and the crestal bone loss (CBL) at the mesial and distal sides were measured. Results: Abutments were tightened after 3.1±0.4 months. All implants but one (96%) resisted the applied 35 Ncm torque. At the 1-year control, all implants were clinically stable and supported the definitive prosthesis. All showed endo-sinus bone gain; the mean gain was 2.5±1.2 mm. The mean CBL was 1.2±0.7 mm. Endo-sinus bone gain and RBH showed a strong negative correlation (r=,0.78 on the mesial side and ,0.80 on the distal side). A good correlation (r=0.73) was found between implant penetration in the sinus and endo-sinus bone gain. Conclusion: Elevation of the sinus membrane alone without addition of bone grafting material can lead to bone formation beyond the original limits of the sinus floor. Despite a limited RBH at implant placement, a healing period of 3 months was sufficient to resist a torque of 35 N cm and to lead to a predictable implant function at the 1-year control. [source]

Effect of donor characteristics, technique of harvesting and in vitro processing on culturing of human marrow stroma cells for tissue engineered growth of bone

CLINICAL ORAL IMPLANTS RESEARCH, Issue 5 2005
Helge Bertram
Abstract: The aim of this study was to assess the effect of donor characteristics and the technique of harvesting and in vitro processing on the efficacy of culturing of human mesenchymal stem cells (hMSCs) for tissue engineered growth of bone. Cultures of hMSCs were derived from iliac crest bone marrow aspirates (21 donors, age 11,76) and from cancellous bone grafting material (32 donors, age 13,84). Age had no significant effect on the ability to isolate and culture hMSCs, although the failure rate was 55.6% in donors beyond the age of 60, while it varied between 14.3% and 22.2% in donors under 60 years of age. Male and female donors had comparable failure rates (27.3% and 28.6%, respectively). Culturing of hMSCs was successful in 90.4% of marrow aspirates from 21 donors and in 62.5% of cancellous bone specimens from 35 donors. This difference was statistically significant (P=0.023). Regression analysis confirmed that at simultaneous testing of the three variables, only the source of cells significantly affected the result (P=0.043). Morphological evaluation of the unfractionated primary population showed a change in cell shape of the adherent cells from a triangular into thin spindle-shaped elongated form, which remains until confluence. When the cultures were exposed to osteoinductive medium, various morphotypes expressing different levels of alkaline phosphatase and secreting different amounts of mineral were evident. Morphology of marrow stroma cells (MSCs) from marrow aspirates was not different from MSCs derived from cancellous bone specimens. Expression of osteogenic markers in MSCs as shown by PCR as well, did not differ between the two sources. It is concluded that marrow aspirates and cancellous bone specimens produce comparable populations of MSCs. However, bone marrow aspirates from donors under the age of 60 years rather than cancellous bone chips are favourable for isolation and expansion of hMSCs for tissue engineered growth of bone. Résumé Le but de cette étude a été d'analyser l'effet des caractéristiques du donneur et la technique de prélèvement et du processus in vitro sur l'efficacité des cultures des cellules souches mésenchymateuses humaines (hMSC) pour la croissance tissulaire en laboratoire de l'os. Les cultures de hMSC provenaient de la moelle osseuse de la crête iliaque (21 donneurs de 11 à 76 ans) et de matériel de greffe osseuse d'os spongieux (32 donneurs de 13 à 84 ans). L'âge n'avait aucun effet significatif sur l'habilitéà isoler et à mettre en culture les hMSC bien que le taux d'échec était de 56% chez les donneurs au-dessus de 60 ans et variait de 14 à 22% chez les donneurs en-dessous de 60 ans. Les hommes et les femmes avaient des taux d'échec comparables de respectivement 27 et 28%. La mise en culture des hMSC a réussi dans 90% des prélèvements de moelle et dans 63% dans les échantillons osseux spongieux. Cette différence était statistiquement significative (P=0,023). L'analyse de régression a confirmé qu'avec un test simultané des trois variables, seul la source de cellules avait un réel effet sur le résultat (P=0,043). L'évaluation morphologique de la population primaire non-fractionnée a montré un changement dans l'apparence des cellules adhérentes depuis un aspect triangulaire à une forme allongée en forme de fuseau qui restait jusqu'à confluence. Lorsque les cultures étaient exposées à un milieu ostéoinductif différents morphotypes exprimant différents niveaux de phosphatase alcaline et secrétant différentes quantitées de minéraux étaient mis en évidence. La morphologie des MSC des prélèvements de la moelle n'était pas différente des MSC provenant des spécimens osseux spongieux. L'expression des marqueurs ostéogéniques dans les MSC ne montrait par PCR aucune différence entre ces deux sources. Les prélèvements de moelle et les spécimens osseux spongieux produisent donc des populations comparables de MSC. Cependant, les aspirations de moelle de donneurs en-dessous de 60 ans plutôt que les chips osseux spongieux sont favorables pour l'isolation et l'expansion des hMSC pour la croissance osseuse en laboratoire. Zusammenfassung Es war das Ziel dieser Studie, den Einfluss von Spender-Merkmalen, Entnahmetechnik und in vitro -Behandlung bei der erfolgreichen Kultivierung von menschlichen mesenchymalen Stammzellen (hMSCs) für das gewebsgesteuerte Knochenwachstum zu untersuchen. Die Kulturen der hMSCs gewann man aus vom Beckenkamm aspiriertem Knochenmark (21 Spender, Alter 11,76) und von Spongiosa aus Spendermaterial (32 Spender, Alter 13,84). Das Alter hatte keinen signifikanten Einfluss auf die erfolgreiche Isolierung und Kultivierung von hMSCs, obgleich die Misserfolgsrate bei Spendern über 60 Jahren 55.6% betrug, währenddem sie bei Spendern unter 60 Jahren zwischen 14.3% und 22.2% variierte. Männer und Frauen hatten vergleichbare Misserfolgsraten (27.3%, beziehungsweise 28.6%). Die Kultivierung von hMSCs war bei 90.4% des aspirierten Marks von 21 Spendern und 62.5% der Spongiosa von 35 Spendern erfolgreich. Diese Differenz war statistisch signifikant (P=0.023). Die Regressionsanalyse bestätigte, dass von den drei gleichzeitig getesteten Variablen nur die Entnahmequelle der Zellen das Resultat signifikant beeinflusste (P=0.043). Die morphologische Untersuchung der unfraktionierten Primärpopulation zeigte bei den adhärenten Zellen eine Veränderung der Zellform von einer dreieckigen zu einer spindelförmigen länglichen Form. Diese blieb bis zu ihrem Zusammenwachsen erhalten. Wurden die Kulturen einem osteoinduktiven Einfluss ausgesetzt, entwickelten sich verschiedene Morphotypen, die auch verschiedene Mengen alkalischer Phosphatase und Mineralien ausschieden. Die Morphologie der MSCs aus dem aspirierten Knochenmark war nicht anders als diejenige von MSCs aus spongiösen Knochenproben. Die Ausscheidung von osteogenen Markern durch die MSCs, auch messbar durch den PCR, verhielt sich bei den Zellen aus beiden Quellen gleich. Man schloss daher, dass aspiriertes Knochenmark und Spongiosa vergleichbare Populationen von MSCs produzieren. Für die Isolation und Expansion von hMSCs zur gesteuerten Knochengewebsregeneration ist aspiriertes Knochenmark vorteilhafter als spongiöse Knochenchips und der Spendern ist von Vorteil jünger als 60 Jahre. Resumen La intención de este estudio fue valorar el efecto de las características del donante y de la técnica de recogida y del procesamiento in vivo sobre la eficacia del cultivo de células madre mesenquimales humanas (hMSCs) para crecimiento óseo por ingeniería tisular. Los cultivos de hMSCs se derivaron de aspirados de la médula ósea de la cresta iliaca (21 donantes, edad 11,76) y de material de injerto de hueso esponjoso (32 donantes, edad 13,84). La edad no tuvo un efecto significativo en la habilidad para aislar y cultivar hMSCs, aunque el índice de fracaso fue del 55.6% en donantes por encima de los 60 años, mientras que varió entre el 14.3% y el 22.2% en donantes por debajo de los 60 años. Los donantes varones y hembras tuvieron índices de fracaso comparables (27.3 y 28.6%, respectivamente). El cultivo de hMSCs tuvo éxito en el 90.4% de los aspirados medulares de 21 donantes y en 62.5% de los especímenes de hueso esponjoso de 35 donantes. Esta diferencia fue estadísticamente significativa (P=0.023). El análisis de regresión confirmó que en la prueba simultanea de las tres variables, solo el origen de las células afectó significativamente el resultado (P=0.043). La evaluación morfológica de la población primaria no fraccionada mostró un cambio en la forma celular de las células adherentes de triangular a una forma de huso fino elongado, que se mantiene hasta su confluencia. Cuando los cultivos se expusieron a un medio osteoconductivo se evidenciaron varios morfotipos manifestando diferentes niveles de fosfatasa alcalina y segregando diferentes cantidades de mineral. La morfología de las MSCs de los aspirados medulares no fue diferente de las MSCs derivadas de los especímenes de hueso esponjoso. La manifestación de marcadores osteogénicos en MSCs mostrado por PCR tampoco difirió entre las dos fuentes. Se concluye que los aspirados medulares y los especímenes de hueso esponjoso producen poblaciones comparables de MSCs. De todos modos, los aspirados de médula ósea de donantes menores de 60 años por encima de las virutas de hueso esponjoso son más favorables para el aislamiento y la expansión de hMSCs para crecimiento óseo por ingeniería tisular. [source]

Bone formation following sinus grafting with autogenous bone-derived cells and bovine bone mineral in minipigs: preliminary findings

CLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2004
Gabor Fuerst
Abstract: Bone formation in a sinus grafted with a cell-free scaffold requires the presence of local progenitor cells that differentiate into osteoblasts. The purpose of this study was to examine the effect of culture expanded autogenous bone-derived cells (ABC) with bovine bone mineral (BBM) on bone formation after single-stage sinus grafting in minipigs. Bone biopsies from the iliac crest were harvested 4 weeks prior to sinus grafting and ABC were culture expanded in vitro. The sinuses of five adult minipigs were grafted. In one sinus of each minipig the space between Schneider's membrane (SM) and the sinus wall was grafted with ABC (325,000 cells per sinus, on average) and BBM. In the other sinus, BBM alone was used. The animals were sacrificed after 12 weeks. One block of each grafted area was prepared by saw cutting and the amount of newly formed bone was analysed by micro-computed tomography (,-CT). The addition of ABC to BBM significantly increased the amount of newly formed bone compared with BBM alone on ,-CT analysis (ABC+BBM: 29.86±6.45% vs. BBM: 22.51±7.28% (P=0.016)). Bone formation was increased near SM (ABC+BBM: 20.7±4.5% vs. BBM: 15.43±3.62% (P=0.009)) and in the middle zone of the grafting material (ABC+BBM: 31.63±7.74% vs. BBM: 22.5±7.91% (P=0.001)), but not near the local host bone (ABC+BBM: 37.23±8.23% vs. BBM: 28.42±12.54% (P=0.15)). These preliminary findings indicate that supplementation of cell-free grafting material with culture expanded ABC can stimulate bone formation in areas with low bone-forming capacity. Résumé La néoformation osseuse dans un sinus grefféà l'aide d'un échafaudage acellulaire requiert la présence de cellules progénitrices locales qui se différencient en ostéoblastes. Le but de cette étude a été d'examiner l'effet de cellules dérivées de l'os autogène (ABC) avec expansion par culture avec un minéral osseux bovin (BBM) sur la formation osseuse après une greffe sinusale en une étape chez le mini-porc. Des biopsies osseuses de la crête iliaque ont été prélevées quatre semaines avant la greffe sinusale et les ABC ont été placées en culture in vitro. Les sinus de cinq mini-porcs adultes ont été greffés. Dans un sinus de chaque mini-porc l'espace entre la membrane de Schneider et la paroi sinusale a été greffé avec les ABC (en moyenne 325 000 cellules/sinus) et BBM. Dans l'autre sinus, BBM seul a été utilisé. Les animaux ont été euthanasiés après douze semaines. Un bloc de chaque aire greffée a été scié et la quantité d'os néoformé a été analysée par tomographie par micro-ordinateur (,-CT). L'addition d'ABC au BBM augmentait significativement la quantité d'os néoformé comparée à l'utilisation du BBM seul lors de l'analyse micro-CT [ABC+BBM : 29,9±6,5% vs BBM : 22,5±7,3% (P=0,016)]. La formation osseuse était augmentée près de la membrane de Schneiderian [ABC+BBM : 20,7±4,5 vs BBM : 15,4±3,6% (P=0,009)] et dans la zone moyenne du matériel greffé [ABC+BBM : 31,6±7,7% vs BBM : 22,5±7,9 (P=0,001)], mais pas dans la région proche de l'hôte (ABC+BBM : 37,2±8,2% vs BBM : 28,4±12,5% (P=0,150). Ces découvertes préliminaires indiquent que l'addition à un matériau acellulaire de ABC en culture d'expansion pouvait stimuler la formation osseuse dans des zones avec des faibles capacités de formation osseuse. Zusammenfassung Knochenformation nach Sinusaugmentation mit autologen Zellen knöchernen Ursprungs und bovinem Knochenmineral in Minipigs: erste Ergebnisse Die Bildung von neuem Knochen im augmentierten Sinus mit einer zellfreien Matrix benötigt lokale Progenitorzellen, welche sich in Osteoblasten differenzieren können. Das Ziel dieser Studie war, den Effekt von in Kultur gezüchteten autologen Zellen knöchernen Ursprungs (ABC) mit bovinem Knochenmineral (BBM) auf die Knochenbildung nach Sinusaugmentation in Minipigs zu untersuchen. Knochenbiopsien vom Beckenkamm wurden 4 Wochen vor der Sinusaugmentation entnommen und die ABC in vitro in einer Kultur vermehrt. Die Kieferhöhlen von 5 ausgewachsenen Minipigs wurden augmentiert. Bei einer Kieferhöhle jedes Minipigs wurde der Raum zwischen der Schneider'schen Membran und der Sinuswand mit ABC (325,000 Zellen pro Sinus in Durchschnitt) und BBM aufgefüllt. In der anderen Kieferhöhle wurde BBM allein verwendet. Die Tiere wurden nach 12 Wochen geopfert. Von jeder augmentierten Region wurde mittels Sägeschnitt ein Block präpariert und die Menge an neu gebildetem Knochen wurde durch Mikro-Computertomographie (,-CT) analysiert. Die Zugabe von ABC zu BBM bewirkte in der ,-CT Analyse eine signifikante Zunahme des neu gebildeten Knochens im Vergleich zu BBM allein (ABC+BBM: 29.86±6.45% gegenüber BBM. 22.51±7.28% (P=0.016)). Die Knochenbildung hatte im Bereich der Schneider'schen Membran (ABC+BBM: 20.7±4.5% gegenüber BBM: 15.43±3.62%(P=0.009)) und in der Mittelzone des Transplantatmaterials (ABC+BBM: 31.63±7.74% gegenüber BBM: 22.5±7.91% (P=0.001)) zugenommen, aber nicht in der Nähe des lokalen Wirtsknochens (ABC+BBM: 37.23±8.23% gegenüber BBM: 28.42±12.54% (P=0.15)). Diese ersten Resultate zeigen, dass der Zusatz von in Kultur gezüchteten ABC zu zellfreien Transplantatmaterialien die Knochenbildung in Regionen mit niedriger Knochenbildungskapazität stimulieren kann. Resumen La formación de nuevo hueso en un seno injertado con una estructura libre de células requiere la presencia de células progenitoras que se diferencien en osteoblastos. El propósito de este estudio fue examinar el efecto de células autógenas derivadas de hueso de cultivo expandido (ABC) con mineral de hueso bovino (BBM) en la formación de hueso tras un injerto del seno en una sola fase en minicerdos. Se tomaron biopsias de hueso de la cresta iliaca 4 semanas antes del injerto del seno y se cultivaron expandidamente las células ABC in vitro. Se injertaron los senos de 5 minicerdos. En un seno de cada minicerdo el espacio entre la membrana de Schneider y la pared del seno se injertó con ABC (325,000 células por seno, de media) y BBM. En el otro seno se uso BBM únicamente. Los animales se sacrificaron tras 12 semanas. Se preparó un bloque de cada área injertada por medio de una sierra y se analizó la cantidad de hueso neoformado por medio de micro tomografía computarizada (,-CT). La adición de ABC a BBM incrementó significativamente la cantidad de hueso neoformado comparado con BBM solo en el análisis de ,-CT [ABC+BBM: 29.86±6.45% vs. BBM: 22.51±7.28% (P=0.016)]. La formación del hueso se incrementó cerca de la membrana de Schneider [ABC+BBM: 20.7±4.5% vs. BBM: 15.43±3.62% (P=0.009)] y en la zona media de del material de injerto [ABC+BBM: 31.63±7.74% vs. BBM: 22.5±7.91% (P=0.001], pero no cerca del hueso huésped local [ABC+BBM: 37.23±8.23% vs. BBM: 28.42±12.54% (P=0.15)]. Estos hallazgos preliminares indican que la suplementación de injertos sin células con ABC de cultivo expandido puede estimular la formación de hueso en áreas con baja capacidad de formación de hueso. [source]

Freeze-dried bone for maxillary sinus augmentation in sheep

CLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2002
Part II: Biomechanical findings
Abstract: This study examines the biomechanical loading capacity of dental implants placed in the posterior maxilla in conjunction with subantral augmentation with either homogeneous demineralized freeze-dried bone from sheep (s-DFDB) or heterogeneous demineralized freeze-dried human bone (h-DFDB) as grafting material in sheep. In 36 adult female mountain sheep, the Schneiderian membrane was elevated extraorally in both maxillary sinuses, and two titanium plasma-flame-sprayed cylindrical implants were inserted in each lateral antral wall. Three groups of 18 maxillary sinuses each were augmented with s-DFDB, h-DFDB and autogenous bone from the illiac crest, respectively. In the remaining 18 sinuses, the subantral hollow space was left empty. Pull-out tests were carried out after intervals of 12, 16 and 26 weeks. The mean pull-out force needed, irrespective of time, was 259.3 N in the empty control group, 356.7 N in the group augmented with autogenous bone, 278.1 N in the test group augmented with h-DFDB and 365.2 N in the group augmented with s-DFDB, revealing no significant difference between the individual groups (P > 0.05). The implants of the group augmented with autogenous bone showed an increase in the mean pull-out force from 223.8 N after 12 weeks to 523.7 N after 26 weeks. The nonaugmented control group yielded values of 248 N after 12 weeks, which rose to 269.8 N at the last test, while the values of the h-DFDB group increased from 275.4 N to 325.4 N. The highest initial pull-out values were obtained in the s-DFDB group. They amounted to 310.5 N after 12 weeks and rose to 481.4 N after 26 weeks. Time thus proved to have a significant influence on the pull-out forces (P = 0.014) with a statistically proven linear trend (P = 0.007). The findings of this experimental study indicate that the use of homogeneous DFDB in one-stage sinus lift procedures results in a mechanical loading capacity of implants comparable to that achieved by autogenous cancellous bone from the iliac crest. In contrast, the use of heterogenous-DFDB resulted in only slightly higher pull-out forces than those observed in the nonaugmented control group after 26 weeks. [source]

Bovine-HA spongiosa blocks and immediate implant placement in sinus augmentation procedures

CLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2002
Histopathological, histomorphometric observations on different histological stainings in 10 consecutive patients
Abstract: Bovine mineral spongiosa block (B-SB) was used as a bone substitute in sinus augmentation procedures in 10 consecutive patients. Implants were placed during the same session. The purpose of this study was to histopathologically examine the healing of the grafted site around the implants at 12 months. Radiographic follow-up showed apparent bone apposition in the augmented area around the implants. Clinically, all 36 implants were stable and integrated with the surrounding tissue. Histopathologically, new bone formation was evident in all specimen hard tissue cores. Hydroxyapatite particles were present in direct contact with the remodeled osseous tissue. Mallory trichrome staining showed different stages of mineralization and maturation of the newly formed bone around the grafted mineral particles. Morphometric evaluation of Picrosirius red stained slides under polarized light microscopy was performed at the peripheral/external and deep section slides of all specimens. The average bone area fraction was 34.2%, with a 1 : 5.4 mean lamellar/woven bone ratio at the peripheral side and 53.0%, with 1 : 2.5 mean ratio at the deep side. The differences of both parameters between the two sites were statistically significant. B-SB proved to be a suitable grafting material with simultaneously placed implants in sinus floor augmentation procedures. [source]

Bone regeneration in rabbit sinus lifting associated with bovine BMP

Stem cells and periodontal regeneration

AUSTRALIAN DENTAL JOURNAL, Issue 2 2008
N-H Lin
Abstract Periodontitis is an inflammatory disease which manifests clinically as loss of supporting periodontal tissues including periodontal ligament and alveolar bone. For decades periodontists have sought ways to repair the damage which occurs during periodontitis. This has included the use of a range of surgical procedures, the use of a variety of grafting materials and growth factors, and the use of barrier membranes. To date periodontal regeneration is considered to be biologically possible but clinically unpredictable. Recently, reports have begun to emerge demonstrating that populations of adult stem cells reside in the periodontal ligament of humans and other animals. This opens the way for new cell-based therapies for periodontal regeneration. For this to become a reality a thorough understanding of adult human stem cells is needed. This review provides an overview of adult human stem cells and their potential use in periodontal regeneration. [source]

Bone Reformation and Implant Integration following Maxillary Sinus Membrane Elevation: An Experimental Study in Primates

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2006
Vinicius C Palma DDS
ABSTRACT Background:, Recent clinical studies have described maxillary sinus floor augmentation by simply elevating the maxillary sinus membrane without the use of adjunctive grafting materials. Purpose:, This experimental study aimed at comparing the histologic outcomes of sinus membrane elevation and simultaneous placement of implants with and without adjunctive autogenous bone grafts. The purpose was also to investigate the role played by the implant surface in osseointegration under such circumstances. Materials and Methods:, Four tufted capuchin primates had all upper premolars and the first molar extracted bilaterally. Four months later, the animals underwent maxillary sinus membrane elevation surgery using a replaceable bone window technique. The schneiderian membrane was kept elevated by insertion of two implants (turned and oxidized, Brånemark System®, Nobel Biocare AB, Göteborg, Sweden) in both sinuses. The right sinus was left with no additional treatment, whereas the left sinus was filled with autogenous bone graft. Implant stability was assessed through resonance frequency analysis (OsstellTM, Integration Diagnostics AB, Göteborg, Sweden) at installation and at sacrifice. The pattern of bone formation in the experimental sites and related to the different implant surfaces was investigated using fluorochromes. The animals were sacrificed 6 months after the maxillary sinus floor augmentation procedure for histology and histomorphometry (bone-implant contact, bone area in threads, and bone area in rectangle). Results:, The results showed no differences between membrane-elevated and grafted sites regarding implant stability, bone-implant contacts, and bone area within and outside implant threads. The oxidized implants exhibited improved integration compared with turned ones as higher values of bone-implant contact and bone area within threads were observed. Conclusions:, The amount of augmented bone tissue in the maxillary sinus after sinus membrane elevation with or without adjunctive autogenous bone grafts does not differ after 6 months of healing. New bone is frequently deposited in contact with the schneiderian membrane in coagulum-alone sites, indicating the osteoinductive potential of the membrane. Oxidized implants show a stronger bone tissue response than turned implants in sinus floor augmentation procedures. [source]

Histologic findings at augmented bone areas supplied with two different bone substitute materials combined with sinus floor lifting

CLINICAL ORAL IMPLANTS RESEARCH, Issue 1 2004
Report of one case
Abstract: This case report is focused on the histologic findings of bone tissue supplied with two different hydroxyapatites (HAs) used for maxillary sinus floor grafting in the same patient after various healing intervals. An insufficient unilateral sinus floor grafting with Bio-Oss® biomaterial was followed by an additional grafting procedure with Algipore® biomaterial performed 4 years later. Bone samples obtained during second-stage dental implantation contained the interesting combination of Bio-Oss®, a bovine anorganic bone substitute, and Algipore®, a porous algae-derived HA, in close vicinity, yet after different healing periods. Light microscopy exhibited satisfactory osseointegration of both grafting materials. However, Bio-Oss® biomaterial showed no evidence of substantial remodeling after a healing period of 4.5 years. On the other hand, Algipore® particles demonstrated signs of remodeling by being locally resorbed and partially replaced with newly formed bone already within 6 months. Résumé Ce rapport d'un cas se concentre sur les découvertes histologiques du tissu osseux apporté par deux hydroxyapatites différents utilisés pour l'épaississement du plancher sinusal chez le même patient après différents intervalles de guérison. Un épaississement sinusal unilatéral insuffisant effectué avec le Bio-Oss® a été suivi d'un nouveau processus d'épaississement avec le Algipore® (un hydroxyapatite biologique dérivé d'algues marines calcifiées) quatre ans plus tard. Des échantillons osseux obtenus durant le placement des implants contenaient la combinaison intéressante du Bio-Oss®, un substitut osseux inorganique bovin, et du Algipore®, un hydroxyapatite d'algues, l'un à côté de l'autre, même si il y avait des périodes de guérison différentes. La microscopie optique a montré une ostéoïntégration satisfaisante des deux matériaux greffés. Cependant, le Bio-Oss® ne montrait aucune évidence d'un remodelage substantiel après une période de 4,5 années. Par contre les particules de Algipore® possèdaient des signes de remodelage tout en étant résorbées localement et partiellement remplacées par de l'os néoformé déjà après six mois. Zusammenfassung Diese Fallvorstellung präsentiert die Histologie eines Knochens, der bei einer in zwei Schritten und mit verschiedenen Hydroxylapatitprodukten durchgeführten Sinusbodenelevation entstanden ist. Die Einheilzeit der zwei Transplantate war verschieden lang. Eine einseitig durchgeführte und ungenügende Sinusbodenelevation mit dem Biomaterial Bio-Oss® wurde vier Jahre später mit einem zusätzlichen Augmentationseingriff unter Einsatz des Biomaterials Algipore® korrigiert. Bei der Implantation konnte man Knochenproben von interessanter Zusammensetzung entnehmen. Es handelte sich um einen Knochen, der während verschieden langer Zeit in engem Kontakt mit Bio-Oss®, einem anorganischen Rinderknochentransplantat, und Algipore®, einem porösen aus Algen gewonnenem Hydroxylapatit stand. Die Lichtmikroskopie zeigte eine zufriedenstellende Osseointegration beider Transplantatmaterialien. Bio-Oss® zeigte jedoch nach einer Einheilzeit von 4.5 Jahren noch keine Anzeichen einer substanziellen Remodellation. Bei den Algipore® Partikeln war dies bereits der Fall. Sie waren schon nach sechs Monaten an einigen Stellen anresorbiert, teilweise sogar mit neu gebildetem Knochen ersetzt. Resumen Este informe de un caso esta enfocado sobre los hallazgos histológicos de tejido óseo suministrado con dos diferentes hidroxiapatitas usadas para injerto del suelo del seno maxilar en el mismo paciente tras varios intervalos de cicatrización. Un insuficiente injerto del suelo del seno con biomaterial Bio-Oss® fue seguido por un procedimiento adicional de injerto con biomaterial Algipore® llevado a cabo 4 años mas tarde. Las muestras de hueso obtenidas durante la segunda fase de la implantación dental contenían una interesante combinación de Bio-Oss®, un sustituto óseo inorgánico bovino y Algipore®, una hidroxiapatita porosa derivada de algas, en próxima vecindad, aunque tras diferentes periodos de cicatrización. La microscopía óptica exhibió una osteointegración satisfactoria de ambos materiales de injerto. De todos modos, el biomaterial Bio-Oss® no mostró evidencia de un remodelado sustancial tras un periodo de cicatrización de 4.5 años. Por otro lado las partículas de Algipore® demostraron signos de remodelado al ser localmente reabsorbidas y reemplazadas parcialmente con hueso neoformado ya a los 6 meses. [source]