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Bone-to-implant Contact (bone-to-implant + contact)
Selected AbstractsHistomorphologic and histomorphometric evaluation of various endosseous implant healing chamber configurations at early implantation times: a study in dogsCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2010Charles Marin Abstract Aim: The objective of this study was to evaluate the early healing of endosseous implants presenting various healing chamber configurations in a beagle dog mandible model. Methods: The four premolars of 12 beagle dogs were extracted and allowed to heal for a period of 8 weeks. Implants allowing six different healing chamber configurations were placed in each dog (three per side, six configurations per dog). The animals were sacrificed after 3 and 5 weeks in vivo (n=6 per time in vivo), and the implants were non-decalcified processed to slides of ,30 ,m thickness. Bone-to-implant contact (BIC) and bone area fraction occupied (BAFO) within the healing chamber were quantified. Statistical analysis was performed by a GLM ANOVA model at 5% significance level. Results: Osseointegration and healing with woven bone filling throughout all healing chambers was observed. Replacement of woven bone by lamellar bone showing primary osteonic structures was observed at 5 weeks. BIC was significantly affected by healing chamber configuration (P<0.001) and was not affected by time in vivo (P>0.42) at 3 and 5 weeks in vivo. BAFO was not affected by healing chamber configuration (P>0.14) however significantly increased over implantation time (P<0.001). Conclusion: Regardless of healing chamber design and dimensions considered, healing allowed the devices osseointegration. However, healing chamber configuration significantly affected osseointegration measurable parameters such as BIC. To cite this article: Marin C, Granato R, Suzuki M, Gil JN, Janal, MN Coelho PG. Histomorhpologic and histomorphometric evaluation of various endosseous implant healing chamber configurations at early implantation times: a study in dogs. Clin. Oral Impl. Res. 21, 2010; 577,583. doi: 10.1111/j.1600-0501.2009.01853.x [source] Injectable calcium phosphate cement as a filler for bone defects around oral implants: an experimental study in goatsCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2002Luca Comuzzi Abstract: The aim of this study was to evaluate the clinical applicability and biological behavior of a newly developed injectable calcium phosphate (Ca-P) cement as bone filler for gaps around oral implants. Twenty-four step-like implants, creating gaps of 1 and 2 mm, were inserted into the trabecular bone of the medial femoral condyles of six goats. Four different situations were tested: (1) implant + gaps; (2) implant + gaps, but covered with a polylactic acid membrane; (3) implant + gaps that were filled with Ca-P cement; and (4) implant + gaps that were filled with Ca-P cement and covered with a membrane. All implants were left in place for 12 weeks. Histological and quantitative histomorphometrical measurements demonstrated that implants + gaps had generally poor bone contact at the implant base. Furthermore, fibrous encapsulation was observed in the gap part. In contrast, the presence of a membrane promoted bone ingrowth into the gap and also the bone contact at the implant base. Injection of Ca-P cement resulted in an almost complete filling of the gaps around the implant. The cement surface was completely covered by bone. Active resorption and remodeling of cement particles was observed, suggesting a pattern of slow resorption associated with full replacement with newly formed bone. Additional use of a membrane did not result in adjunctive benefits. Bone-to-implant contact at the implant base was comparable with the implants provided only with a membrane. In conclusion, the Ca-P cement used here showed excellent clinical handling properties combined with a superior bone behavior. On the other hand, the degradation rate of the material was still very slow. This current characteristic can hamper the final clinical applicability of the material as gap filler for periimplant or periodontal defects. Résumé Le but de l'étude présente a été d'évaluer l'application clinique et le comportement biologique d'un nouveau ciment de calcium de phosphate injectable (Ca-P) comme comblement osseux pour les cavités autour des implantes dentaires. Vingt-quatre implants créant des cavités de 1 et 2 mm ont été insérés dans l'os trabéculaire des condyles fémoraux moyens de six chèvres. Quatre situations différentes ont été testées: 1) implant + cavités; 2) implant = cavités recouvertes par une membrane en acide polylactique, 3) implant + cavités comblées par le ciment Ca-P et 4) implant + cavités comblées par le ciment Ca-P et recouvertes par une membrane. Tous les implants ont été laissés in situ pendant douze semaines. Les mesures histologiques et quantitatives histomorphométriques ont démontré que les implants + cavités avaient généralement un contact osseux pauvre au niveau de la base implantaire. De plus, une encapsulation fibreuse était observée dans la partie cavité. Par contre, la présence d'une membrane favorisait la croissance osseuse dans la cavité ainsi que le contact osseux à la base de l'implant. L'injection du cément Ca-P résultait en une réparation quasi complète des cavités autour de l'implant. La surface cémentaire était complètement recouverte d'os. La résorption active et le remodelage des particules de cément étaient observés, ce qui suggérait un système de résorption lente associéà un remplacement complet par de l'os néóformé. L'usage additionnel d'une membrane ne s'accompagnait pas de bénéfice supplémentaire. Le contact os/implant à la base de l'implant était comparable à celui des implants installés seulement avec une membrane. En conclusion, le ciment Ca-P possèdait des propriétés cliniques excellentes combinées à un comportement osseux supérieur. Par contre le taux de dégradation du matériel était toujours très lent. Cette caractéristique pourrait gêner l'application clinique finale de ce matériel en tant que comblement des cavités autour des implants ou dans les lésions parodontales. Zusammenfassung Das Ziel dieser Studie war es, die klinische Anwendbarkeit und das biologische Verhalten eines neu entwickelten injizierbaren Kalziumphosphatzements (Ca-P) als Knochenfüller bei oralen Implantaten auszuwerten. Vierundzwanzig stufenförmige Implantate, welche Defekte von 1 und 2 mm kreieren, wurden in den trabekulären Knochen der medialen femoralen Kondylen von 6 Ziegen eingesetzt. Vier verschiedene Situationen wurden getestet: 1) Implantat + Defekte; 2) Implantat + Defekte, aber bedeckt mit einer Membran aus Polimilchsäure; 3) Implantat + Defekte, welche mit Ca-P-Zement gefüllt wurden; 4) Implantat + Defekte, welche mit Ca-P-Zement gefüllt und mit einer Membran bedeckt wurden. Alle implantate wurden 12 Wochen belassen. Histologische und quantitative histomorphometrische Messungen zeigten, dass Implantate + Defekte generell schlechten Knochenkontakt an der Implantatbasis aufwiesen. Ausserdem wurde eine fibröse Einkapselung im Bereich der Defekte beobachtet. Im Gegensatz dazu bewirkte die Präsenz einer Membran das Einwachsen von Knochen in die Defekte und der Knochenkontakt an der Implantatbasis wurde gefördert. Die Injektion von Ca-P-Zement resultierte in einer fast kompletten Auffüllung der Defekte um die Implantate. Die Zementoberfläche war völlig mit Knochen bedeckt. Es konnte eine aktive Resorption und eine Remodellierung der Zementpartikel beobachtet werden. Dies lässt ein Muster mit langsamer Resorption assoziiert mit komplettem Ersatz durch neugebildeten Knochen vermuten. Die zusätzliche Verwendung einer Membran brachte keine weiteren Vorteile. Der Knochen-/Implantat-Kontakt an der Implantatbasis war vergleichbar mit den Implantaten, die nur mit einer Membran abgedeckt worden waren. Zusammenfassend kann festgehalten werden, dass der verwendete Ca-P-Zement eine exzellente Handhabung kombiniert mit ausserodentlichem Knochenverhalten zeigte. Andererseits war die Zersetzungsrate des Materials immer noch sehr Gering. Diese momentanen Eigenschaften können letztendlich die klinische Anwendbarkeit des Materials als Defektfüller bei periimplantären und parodontalen Defekten behindern. Resumen La intención del presente estudio fue evaluar la aplicabilidad clínica y el comportamiento biológico de un cemento recientemente desarrollado de fosfato de calcio (Ca-P) como relleno óseo para huecos alrededor de los implantes orales. Se insertaron veinticuatro implantes del tipo escalón creando huecos de 1 y 2 mm en el hueso trabecular de los cóndilos femorales mediales de 6 cabras. Se probaron cuatro situaciones diferentes: 1) implantes + huecos; 2) implantes + huecos, pero cubiertos con una membrana de ácido poliláctico; 3) implantes + huecos que se rellenaron con cemento de Ca-P; y 4) + huecos que se rellenaron con cemento de Ca-P y se cubrieron con una membrana. Todos los implantes se dejaron en su lugar durante 12 semanas. las mediciones histológicas e histomorfométricas cuantitativas demonstraron que los implantes + huecos tuvieron generalmente un contacto óseo pobre en la base del implante. Posteriormente, se observó una encapsulación fibrosa en la parte del hueco. En contraste, la presencia de la membrana promocionó el crecimiento óseo hacia el hueco y también el contacto óseo en la base del implante. La inyección de cemento Ca-P resultó en un casi completo relleno de los huecos alrededor del implante. La superficie del cemento se cubrió completamente de hueso. La reabsorción activa y la remodelación de las partículas de cemento fueron observadas, lo cual sugiere un patrón de reabsorción lenta asociada con una completa sustitución con hueso neoformado. El uso adicional de la membrana no resultó en beneficios adicionales. El contacto hueso implante en la base del implante fue comparable con los implantes que solo tenían la membrana. En conclusión, el uso de cemento de Ca-P mostró excelentes propiedades de manejo clínico combinado con un superior comportamiento óseo. Por otro lado, el índice de degradación del material fue muy lento. Estas características actuales pueden estorbar la aplicabilidad clínica final del material como rellenador de huecos alrededor de defectos periodontales o perimplantarios. [source] Mesenchymal stem cells and platelet-rich plasma enhance bone formation in sinus grafting: a histomorphometric study in minipigsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2008Francesco 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] Influence of controlled immediate loading and implant design on peri-implant bone formationJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 2 2007Katleen Vandamme Abstract Aim: Tissue formation at the implant interface is known to be sensitive to mechanical stimuli. The aim of the study was to compare the bone formation around immediately loaded versus unloaded implants in two different implant macro-designs. Material and Methods: A repeated sampling bone chamber with a central implant was installed in the tibia of 10 rabbits. Highly controlled loading experiments were designed for a cylindrical (CL) and screw-shaped (SL) implant, while the unloaded screw-shaped (SU) implant served as a control. An F -statistic model with ,=5% determined statistical significance. Results: A significantly higher bone area fraction was observed for SL compared with SU (p<0.0001). The mineralized bone fraction was the highest for SL and significantly different from SU (p<0.0001). The chance that osteoid- and bone-to-implant contact occurred was the highest for SL and significantly different from SU (p<0.0001), but not from CL. When bone-to-implant contact was observed, a loading (SL versus SU: p=0.0049) as well as an implant geometry effect (SL versus CL: p=0.01) was found, in favour of the SL condition. Conclusions: Well-controlled immediate implant loading accelerates tissue mineralization at the interface. Adequate bone stimulation via mechanical coupling may account for the larger bone response around the screw-type implant compared with the cylindrical implant. [source] Bone regeneration in dehiscence-type defects at chemically modified (SLActive®) and conventional SLA titanium implants: a pilot study in dogsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 1 2007Frank Schwarz Abstract Objectives: The aim of the present study was to evaluate bone regeneration in dehiscence-type defects at titanium implants with chemically modified (mod) and conventional sand-blasted/acid-etched (SLA) surfaces. Material and Methods: Standardized buccal dehiscence defects (height: 3 mm, width: 3 mm) were surgically created following implant site preparation in both the upper and lower jaws of four beagle dogs. modSLA and SLA implants were inserted bilaterally according to a split-mouth design. The animals were sacrificed after 2 and 12 weeks (n=2 animals each). Dissected blocks were processed for histomorphometrical analysis: defect length, new bone height (NBH), percent linear fill (PLF), percent of bone-to-implant contact (BIC-D) and area of new bone fill (BF). Results: Wound healing at SLA implants was predominantly characterized by the formation of a dense connective tissue at 2 and 12 weeks, without significant increases in mean NBH, PLF, BIC-D or BF values. In contrast, modSLA implants exhibited a complete defect fill at 12 weeks following implant placement. In particular, histomorphometrical analysis revealed the following mean values at 12 weeks: NBH (3.2±0.3 mm), PLF (98%), BIC-D (82%) and BF (2.3±0.4 mm2). Conclusion: Within the limits of the present study, it was concluded that modSLA titanium surfaces may promote bone regeneration in acute-type buccal dehiscence defects at submerged implants. [source] Influence of different treatment approaches on non-submerged and submerged healing of ligature induced peri-implantitis lesions: an experimental study in dogsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2006Frank Schwarz Abstract Objective: The aim of the present study was to evaluate non-submerged and submerged healing of ligature induced peri-implantitis in dogs. Material and Methods: Peri-implantitis was induced by ligature placement in five beagle dogs (n=30 implants). The defects were randomly and equally allocated in a split-mouth design to either closed treatment+non-submerged healing (CNS), or open treatment+submerged healing (OS) using an Er:YAG laser (ERL), an ultrasonic device (VUS), or plastic curettes+local application of metronidazole gel (PCM), respectively. The animals were sacrificed after 3 months. Clinical, radiological and histological (e.g. new bone-to-implant contact (BIC)) parameters were assessed. Results: All treatment procedures resulted in statistically significant improvements of all clinical parameters at both CNS and OS implants. Radiological improvements were merely observed at OS implants. Histomorphometrical analysis revealed that all CNS implants exhibited comparable low amounts of new BIC (1.0,1.2%), while mean BIC was statistically significant higher in the respective OS groups [ERL (44.8%), PCM (14.8%), VUS (8.7%)]. Conclusion: Within the limits of the present study, it was concluded that (i) OS improved the outcome of treatment in comparison with CNS and (ii) ERL seemed to be more suitable to promote re-osseointegration than PCM and VUS. [source] Bone reactions to longstanding functional load at implants: an experimental study in dogsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 9 2005T. Berglundh Abstract Objectives: The aims of the present investigation were (i) to study marginal bone level alterations following implant installation, abutment connection and functional loading and (ii) to analyse bone tissue reactions to functional load. Material and Methods: Six beagle dogs, about 1-year old, were used. All mandibular pre-molars were extracted. Three months later four implants of the Astra Tech Implants® Dental System were installed in one side of the mandible and four standard fixtures of the Brånemark System® were placed in the contralateral side of the mandible. Abutment connection was performed 3 months later and a plaque control programme was initiated. Three months after abutment connection fixed partial dentures (FPDs) made in gold were cemented to the maxillary canines and pre-molars. FPDs were also connected to the three posterior implants in each side of the mandible, while the mesial implant in each side was used as an unloaded control. Radiographs were obtained from all implant sites following implant installation, abutment connection and FPD placement. Ten months after the FPD placement the radiographic examination was repeated. The animals were sacrificed and biopsies from all implant sites were obtained and prepared for histological analysis. Results: The radiographic analysis revealed that largest amount of bone loss occurred following implant installation and abutment connection and that this loss was more pronounced at Brånemark than at Astra implants. The bone level alterations that were observed at implants exposed to 10 months of functional load in both implant systems were small and did not differ from control sites. The histological analysis revealed that implants exposed to functional load exhibited a higher degree of bone-to-implant contact than control implants in both implant systems. Conclusion: It is suggested that functional load at implants may enhance osseointegration and does not result in marginal bone loss. [source] Covalently-linked hyaluronan promotes bone formation around Ti implants in a rabbit modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2009Marco Morra Abstract The goal of this study was the in vivo evaluation of nanoporous titanium (Ti) implants bearing a covalently linked surface hyaluronan (HA) layer. Implant surface topography and surface chemistry were previously evaluated by scanning electron micorscopy and X-ray photoelectron spectroscopy. Results showed that the surface modification process did not affect surface topography, yielding a homogeneously HA-coated nanotextured implant surface. In vivo evaluation of implants in both cortical and trabecular bone of rabbit femurs showed a significant improvement of both bone-to-implant contact and bone ingrowth at HA-bearing implant interfaces at 4 weeks. The improvement in osteointegration rate was particularly evident in the marrow-rich trabecular bone (bone-to-implant contact: control 22.5%; HA-coated 69.0%, p,<,0.01). Mechanical testing (push-out test) and evaluation of interfacial bone microhardness confirmed a faster bone maturation around HA-coated implants (Bone Maturation Index: control 79.1%; HA-coated 90.6%, p,<,0.05). Suggestions based on the biochemical role of HA are presented to account for the observed behavior. Published by Wiley Periodicals, Inc. J Orthop Res 27: 657,663, 2009 [source] Local alendronate increases fixation of implants inserted with bone compaction: 12-week canine studyJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2007Thomas Jakobsen Abstract Bone compaction has been shown to increase initial implant fixation. Furthermore, bone compaction creates a peri-implant zone of autograft that exerts osteoconductive properties. We have previously shown that locally applied bisphosphonate (alendronate) at 4-week observation can preserve the autograft generated by bone compaction. We now investigate whether the increased amount of autograft, seen at 4 weeks, can increase implant osseointegration and biomechanical fixation. Porous-coated titanium implants were bilaterally inserted with bone compaction into the proximal part of tibia of 10 dogs. On the right side, local bisphosphonate was injected into the bone cavity prior to bone compaction immediately prior to implant insertion. On the left side, saline was used as control. Observation period was 12 weeks. Locally applied bisphosphonate significantly increased biomechanical implant fixation (approximately twofold), bone-to-implant contact (1.2-fold), and peri-implant bone volume fraction (2.3-fold). This study indicates that local alendronate treatment can increase early implant osseointegration and biomechanical fixation of implants inserted by use of bone compaction. Long term effects remain unknown. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:432,441, 2007 [source] Parameters for Successful Implant Integration Revisited Part I: Immediate Loading Considered in Light of the Original Prerequisites for OsseointegrationCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2010FACD, Oded Bahat BDS ABSTRACT Purpose: With the increasing popularity and publication of loading implants at the time of placement, including at time of dental extraction and simultaneous with reconstructive procedures, the objective was to evaluate known variables identified for a traditional unloaded healing period and determine the applicability of these variables to immediate loading. Materials: A total of 124 published reports available as of January 2008 that contained information about loading from the time of surgery up to 3 months postsurgically were examined in light of published variables affecting osseointegration based on a 2 stage surgical approach. Methods: The articles were examined to differentiate between immediate loading (within the initial 48 hours) and early/delayed loading of implants. Success or survival criteria were noted, and where reasons for failure were available, categorized according to six variables considered as determinants for maintaining a long-term bone-to-implant contact. Results: Approximately 60 of the 124 reports described immediately loading implants within 48 with single-tooth, partial, and full-arch restorations, as well as implant overdentures. The implant success or survival rates ranged from 70.8% to 100%. Most studies considered implant survival to be the only criterion for success. Conclusions: Of six parameters identified in 1981 as influencing osseointegration, two parameters (the status of the bone/implant site and implant loading conditions) appear to have diagnostic implications, whereas three (implant design, surgical technique, and implant finish) may affect immediate loading positively or adversely. [source] Effects of a Mechanical Barrier on the Integration of Cortical Onlay Bone Grafts Placed Simultaneously with Endosseous ImplantCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2002Luiz Z. Salata DDS ABSTRACT Background: Previous experimental studies on onlay bone graft integration have shown either advantages or disadvantages to the use of mechanical barriers. This indicates that the role played by the biologic properties of transplanted bone and membrane in graft revascularization and bone remodeling has not yet been established. The outcomes regarding osseointegration of titanium dental implants applied in such a condition are still contradictory. Purpose: The rabbit's radius model that is grafted onto the mandibular lower border and covered by membrane can reproduce a challenging experimental situation to preliminarily study the factors involved in osseointegration under deprived blood vessels source. Materials and Methods: Fourteen New Zealand White rabbits had a 2.5-cm segment of the right radius osteoectomized and fixed onto the right mandibular lower border using titanium screws. Two screw-shaped titanium implants (2.5 mm wide 2.5 mm long) were installed 7 mm apart in the mid length of the grafted bone. In experimental sites, the graft with the implants and graft-host bone junction were covered by expanded polytetrafluoroethylene (e-PTFE) membrane; control sites were left uncovered. Eight animals from the experimental group and six animals from the control group were sacrificed at 6 and 24 weeks after surgery. Ground sections obtained from en bloc tissues containing graft, implants, and recipient bone were subjected to histologic evaluation and histomorphometric analysis (area occupied by the graft and bone-to-implant contact). Results: The graft showed significantly more resorption after 24 weeks than at 6 weeks (p .05) irrespective of the treatment (with or without membrane), although the amount of new bone was greater at 24 weeks in sites where a membrane was covering the graft. Compared with 6 weeks postoperatively, the bone-to-implant contact was considerably improved at 24 weeks (p .05), and the membrane seemed beneficial for implant osseointegration when compared with unprotected sites (p .05). As a result of graft resorption, the amount of soft tissue was considerably expanded in sites beneath membrane, accompanied by a sustained process of trabecular bone deposition close to the barrier. Conclusions: Cortical onlay grafts covered by membrane demonstrated delayed remodeling, probably as a consequence of a hindered process of graft revascularization. Grafts covered by membrane might rely on previous host bone resorption both to become revascularized and to remodel. The findings that the membrane-protected grafts were most resorbed at 24 weeks might be attributable to better implant osseointegration, because the fixtures were exposed to greater mechanical stimulation in these sites. [source] Collagen membranes at immediate implants: a histomorphometric study in dogsCLINICAL ORAL IMPLANTS RESEARCH, Issue 9 2010Marco Caneva Abstract Aim: To evaluate the influence of resorbable membranes on hard tissue alterations and osseointegration at implants placed into extraction sockets in a dog model. Material and methods: In the mandibular premolar region, implants were installed immediately into the extraction sockets of six Labrador dogs. Collagen-resorbable membranes were placed at the test sites, while the control sites were left uncovered. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation. Results: After 4 months of healing, a control implant was not integrated (n=5). Both at the test and at the control sites, bone resorption occurred. While the most coronal bone-to-implant contact was similar between the test and the control sites, the alveolar bone crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 1.7 mm) compared with the control sites (loss: 2.2 mm). Conclusions: The use of collagen-resorbable membranes at implants immediately placed into extraction sockets contributed to a partial (23%) preservation of the buccal outline of the alveolar process. To cite this article: Caneva M, Botticelli D, Salata LA, Souza SLS, Carvalho Cardoso L, Lang NP. Collagen membranes at immediate implants: a histomorphometric study in dogs. Clin. Oral Impl. Res. 21, 2010; 891,897. doi: 10.1111/j.1600-0501.2010.01946.x [source] Influence of interimplant distances and placement depth on peri-implant bone remodeling of adjacent and immediately loaded Morse cone connection implants: a histomorphometric study in dogsCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2010Raquel R. M. Barros Abstract Objectives: The aim of this study was to histomorphometrically evaluate the influence of interimplant distances (ID) and implant placement depth on bone remodeling around contiguous Morse cone connection implants with ,platform-shifting' in a dog model. Material and methods: Bilateral mandibular premolars of six dogs were extracted, and after 12 weeks, each dog received 8 implants, four placed 1.5 mm subcrestally (SCL) on one side of the mandible and four placed equicrestally (ECL) on the other side, alternating the ID of 2 and 3 mm. The experimental groups were SCL with IDs of 2 mm (2 SCL) and 3 mm (3 SCL) and ECL with IDs of 2 mm (2 ECL) and 3 mm (3 ECL). Metallic crowns were immediately installed. After 8 weeks, the animals were euthanized and histomorphometric analyses were performed to compare bone remodeling in the groups. Results: The SCL groups' indices of crestal bone resorption were significantly lower than those of ECL groups. In addition, the vertical bone resorption around the implants was also numerically inferior in the SCL groups, but without statistical significance. No differences were obtained between the different IDs. All the groups presented similar good levels of bone-to-implant contact and histological bone density. Conclusion: The subcrestal placement of contiguous Morse cone connection implants with ,platform shifting' was more efficient in preserving the interimplant crestal bone. The IDs of 2 and 3 mm did not affect the bone remodeling significantly under the present conditions. To cite this article: Barros RRM, Novaes AB Jr., Muglia VA, Iezzi G, Piattelli A. Influence of interimplant distances and placement depth on peri-implant bone remodeling of adjacent and immediately loaded Morse cone connection implants: a histomorphometric study in dogs. Clin. Oral Impl. Res. 21, 2010; 371,378. doi: 10.1111/j.1600-0501.2009.01860.x [source] Osseointegration of titanium alloy and HA-coated implants in healthy and ovariectomized animals: a histomorphometric studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 11 2009Guaracilei Maciel Vidigal Jr Abstract Objectives: The objective of the present study is to evaluate the response to dental implants in healthy and osteoporotic bone. Materials and methods: Ten ovariectomized (OVX) New Zealand rabbits submitted to a hypocalcic diet and 10 sham-aged rabbits were used. All animals were submitted to bone mineral density (BMD) measurements before ovariectomy, and also 4 months afterwards, using dual energy X-ray absorptiometry. The BMD measurements showed a significant loss of bone mass, between the first and second examinations, only in the experimental group (P<0.05). After the bone mass loss induction period, three different implants were installed in the proximal tibia metaphisis of each animal: a titanium alloy implant (Ti), a plasma-spray hydroxyapatite-coated implant (HA-PS), and another implant coated with hydroxyapatite with the biomimetic process (HA-B). Results: After 3 months, histomorphometry showed a bone-to-implant contact (BIC) for Ti implants of 73.09±13.74% in healthy and 66.09±30.01% in OVX animals. The BIC for the HA-PS was 64.83±15.65% and 90.17±8.14% for healthy and OVX animals, respectively, and 88.66±5.30% and 87.96±10.71% for the HA-B implants placed in the same conditions. The differences between the implants in healthy and OVX conditions were not statistically significant (P>0.05). The only significant difference within groups was observed in the healthy animals between HA-B and Ti implants (P<0.06). Conclusion: Within the parameters used in this animal model it was not possible to observe BIC differences between osteoporotic and healthy animals. [source] Bone tissue responses to glass fiber-reinforced composite implants , a histomorphometric studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2009A. M. Ballo Abstract Objectives: The aims of this study were to evaluate bone-to-implant contact (BIC) and the osteoconductive capacity of bioactive fiber-reinforced composite implant (FRC) in vivo. Material and methods: Threaded sand-blasted FRC implants and threaded FRC implants with bioactive glass (BAG) were fabricated for the study. Titanium implants were used as a reference. Eighteen implants (diameter 4.1 mm, length 10 mm) were implanted in the tibia of six pigs using the press-fit technique. The animals were sacrificed after 4 and 12 weeks. Histomorphometric and scanning electron microscopic (SEM) analyses were performed to characterize BIC. Results: In general, the highest values of BIC were measured in FRC-BAG implants, followed by FRC and Ti implants. At 4 weeks, the BIC was 33% for threaded FRC-BAG, 27% for FRC and 19% for Ti. At 12 weeks, BIC was 47% for threaded FRC-BAG, 40% for FRC and 42% for Ti. Four weeks after implantation, all the implants appeared biologically fixed by a newly formed woven bone arranged in the thin bone trabeculae filling the gap between the implant and the bone of the recipient site. Twelve weeks after implantation, the thickness of the woven bone trabeculae had increased, especially around the FRC-BAG implants. Conclusion: Our results suggest that the FRC implant is biocompatible in bone. The biological behavior of FRC was comparable to that of Ti after 4 and 12 weeks of implantation. Furthermore, the addition of BAG to the FRC implant increased peri-implant osteogenesis and bone maturation. [source] Biomechanical and histological behavior of zirconia implants: an experiment in the ratCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2009Ralf J. Kohal Abstract Objective: This study aimed at evaluating the integration of zirconia implants in a rat femur model. Material and methods: Zirconia implants with two distinct surface topographies were compared with titanium implants with similar topographies. Titanium and zirconia implants were placed into the femurs of 42 male Sprague,Dawley rats. Four groups of implants were utilized: machined zirconia implants, zirconia implants with a rough surface, machined titanium implants, and titanium implants with an electrochemically roughened surface. After a healing period of 28 days, the load-bearing capacity between the bone and the implant surface was evaluated by a push-in test. Additionally, after a healing period of 14 and 28 days, respectively, bone tissue specimens containing the implants were processed and histologically analyzed. Results: The mean mineralized bone-to-implant contact showed the highest values after 14 and 28 days for the rough surfaces (titanium: 36%/45%; zirconia: 45%/59%). Also, the push-in test showed higher values for the textured implant surfaces, with no statistical significance between titanium (34 N) and zirconia (45.8 N). Conclusions: Within the limits of the animal investigation presented, it was concluded that all tested zirconia and titanium implant surfaces were biocompatible and osseoconductive. The presented surface modification of zirconia implants showed no difference regarding the histological and biomechanical results compared with an established electrochemically modified titanium implant surface. [source] Subcrestal placement of two-part implantsCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2009Maria Welander Abstract Objective: The aim of the present experiment was to study the healing around two-part implants that were placed in a subcrestal position. Material and methods: Five mongrel dogs, about 2 years old, were included. The mandibular premolars and the first, second and third maxillary premolars were extracted. Three months later two test and two control implants (OsseoSpeedÔ, 3.5 mm × 8 mm) were placed in one side of the mandible. The implants were placed in such a way that the implant margin was located 2 mm apical to the bone crest. In the test implants, the surface modification extended to the implant margin and, thus, included the shoulder part of the implant. Regular abutments with a turned surface (ZebraÔ) were connected to the control implants, while experimental abutments with a modified surface (TiOblastÔ) were connected to the test implants. A plaque control program that included cleaning of implants and teeth every second day was initiated. Four months later the dogs were euthanized and biopsies were obtained and prepared for histological analysis. Results: The marginal bone level at the test implants was identified in a more coronal position than that at the control implants. In 40% of the test implants, the bone-to-implant contact extended coronal of the abutment/fixture (A/F) border, i.e. in contact with the abutment part of the implant. The connective tissue portion of the peri-implant mucosa that was facing the test abutments contained a higher density of collagen and a smaller proportion of fibroblasts than that at the control sites. Conclusion: It is suggested that osseointegration may occur coronal to the A/F interface of two-part implants. Such a result, however, appears to depend on the surface characteristics of the implant components. [source] Histomorphometric analysis of the osseointegration of four different implant surfaces in the femoral epiphyses of rabbitsCLINICAL ORAL IMPLANTS RESEARCH, Issue 11 2008Laurent Le Guehennec Abstract Objectives: The surface properties of titanium dental implants are key parameters for rapid and intimate bone,implant contact. The osseointegration of four implant surfaces was studied in the femoral epiphyses of rabbits. Material and methods: Titanium implants were either grit-blasted with alumina or biphasic calcium phosphate (BCP) ceramic particles, coated with a thin octacalcium phosphate (OCP) layer, or prepared by large-grit sand blasting and acid-etched (SLA). After 2 and 8 weeks of implantation, the bone-implant contact and bone growth inside the chambers were compared. Scanning electron microscopy (SEM) and profilometry showed distinct microtopographies. Results: The alumina-Ti, BCP-Ti and OCP-Ti groups had similar average surface roughness in the 1,2 ,m range whereas the SLA surface was significantly higher with a roughness averaging 4.5 ,m. Concerning the osseointegration, the study demonstrated a significantly greater bone-to-implant contact for both the SLA and OCP-Ti surfaces as compared with the grit-blasted surfaces, alumina- and BCP-Ti at both 2 and 8 weeks of healing. Conclusion: In this animal model, a biomimetic calcium phosphate coating gave similar osseointegration to the SLA surface. This biomimetic coating method may enhance the apposition of bone onto titanium dental implants. [source] Immediate functional loading of TiOblast dental implants in full-arch edentulous mandibles: a 3-year prospective studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 7 2008H. De Bruyn Abstract Introduction: Implant-prosthetic rehabilitation of the completely edentulous mandible has evolved to a simplified procedure with shorter treatment time and survival rates of 95,100% depending on the implant system used. Purpose: The aim was to evaluate the 3-year clinical success of Astra Tech TiOblast implants, functionally loaded on the day of surgery with a fixed full-arch bridge in the mandible. Materials and methods: One hundred and twenty-five implants of 3.5,4 mm width and 11,17 mm length were installed in 25 edentulous mandibles of 15 female and 10 male patients. Implants were functionally loaded on the day of surgery with a provisional, acrylic, glassfibre reinforced, 10 unit bridge. After 3,4 months, the final 12-unit bridge was constructed. Radiographical bone loss was measured on peri-apical radiographs after 3, 12, 24 and 36 months. Results: All implants were functional during the whole study period yielding a survival rate of 100%. None of the fixtures showed pain or mobility after manual torque with 20 N cm at the 3-month control. Mean radiographical bone loss after 3 months and 1, 2 and 3 years was 0.6 mm (SD 0.7), 0.8 mm (SD 0.8), 1 mm (SD 0.8) and 1.3 (SD 1) respectively, which was statistically significantly increasing up to 1 year. Conclusion: Immediate loading of full-arch mandibular bridgework on five TiOblast implants offers a long-lasting clinical result with 100% fixture survival and stable bone-to-implant contact up to 3 years. [source] Injectable calcium phosphate cement as a graft material for maxillary sinus augmentation: an experimental pilot studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2008Ali Aral Abstract Objectives: The aim of the present study was to evaluate the efficiency of injectable CaP cement as a graft material around dental implants in the maxillary sinus augmentation procedure. Material and methods: Bilateral sinus augmentation process was carried out in three sheep and two implants were inserted during the same session. Out of a total of 12 installed implants, eight belonged to the so-called experimental group. In the experimental group, injectable CaP cement was used as augmentation material while autologous bone served as control. Results: Histological examination revealed that newly formed bone surrounded the cement completely without an intervening fibrous tissue layer. Following a healing period of 12 weeks, mean bone-to-implant contact (BIC) values in the experimental and control groups were 36±5 and 37±3, respectively. The percentage of BIC was comparable with other experimental sinus augmentation studies. Further, it appeared that the thickness of the cortical bone that covered the outer surface of the maxillary sinus was <2,3 mm, which affected the primary stability of the implants negatively. Conclusion: CaP cement is indeed effective to stimulate bone formation in the sinus elevation procedure. Nevertheless, additional improvements in the cement composition are required to allow final clinical utilization of the material. [source] Immunohistochemical characterization of guided bone regeneration at a dehiscence-type defect using different barrier membranes: an experimental study in dogsCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2008Frank 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] Bone regeneration of dental implant dehiscence defects using a cultured periosteum membraneCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2008Daiki Mizuno Abstract Objectives: This study aimed to demonstrate the feasibility of a cultured periosteum (CP) membrane for use in guided bone regeneration at sites of implant dehiscence. Material and methods: Four healthy beagle dogs were used in this study. Implant dehiscence defects (4 × 4 × 3 mm) were surgically created at mandibular premolar sites where premolars had been extracted 3 months back. Dental implants (3.75 mm in diameter and 7 mm in length) with machined surfaces were placed into the defect sites (14 implants in total). Each dehiscence defective implant was randomly assigned to one of the following two groups: (1) PRP gel without cells (control) or (2) a periosteum membrane cultured on PRP gel (experimental). Dogs were killed 12 weeks after operation and nondecalcified histological sections were made for histomorphometric analyses including percent linear bone fill (LF) and bone-to-implant contact (BIC). Results: Bone regeneration in the treatment group with a CP membrane was significantly greater than that in the control group and was confirmed by LF analysis. LF values in the experimental and the control groups were 72.36±3.14% and 37.03±4.63%, respectively (P<0.05). The BIC values in both groups were not significantly different from each other. The BIC values in the experimental and the control groups were 40.76±10.30% and 30.58±9.69%, respectively (P=0.25) and were similar to native bone. Conclusion: This study demonstrated the feasibility of a CP membrane to regenerate bone at implant dehiscence defect. [source] Effect of platelet-rich plasma on the early bone formation around Ca-P-coated and non-coated oral implants in cortical boneCLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2008Dimitris Nikolidakis Abstract Objectives: The purpose of the present study was to investigate the effect of local application of platelet-rich plasma (PRP) on the early healing of cortical bone around Ti implants with two different surface configurations. Material and methods: Six goats were used in this study. PRP fractions were obtained from a venous blood sample of the goats and administered immediately before implant insertion. PRP was applied via gel preparation and installation of the gel into the implant site, or via dipping of the implants in PRP fraction before insertion. A total of 36 implants (18 non-coated and 18 Ca-P-coated) were placed into the tibial cortical bone. The animals were sacrificed at 6 weeks after implantation and implants with surrounding tissue were prepared for histological examination. Histomorphometrical variables like the percentage of implant surface with direct bone,implant contact and the percentage of new and old bone adjacent to the implant were evaluated. Results: More interfacial bone-to-implant contact was observed for all the three groups of Ca-P-coated implants and the Ti/PRP liquid group. All groups revealed similar percentages of old and new bone adjacent to the implant. Conclusions: It was concluded that the additional use of PRP did not have any effect on the early cortical bone response to the Ca-P-coated implants, while PRP in a liquid form showed a tendency to increase bone apposition to roughened titanium implants. [source] Histological evaluation of oral implants inserted with different surgical techniques into the trabecular bone of goatsCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2007Manal M. Shalabi Abstract Objective: The aim of this study was to investigate the influence of implant surface topography and surgical technique on bone response. Material and methods: For the experiment, 48 screw-designed implants were used with two different surface finishes, i.e. machined and ,blasted, etched'. The implants were inserted into the left and right medial femoral condyle of eight goats using three different surgical approaches: press-fit (implant diameter=implant bed diamete(r), undersized (implant bed diameter Effects of a novel calcium titanate coating on the osseointegration of blasted endosseous implants in rabbit tibiaeCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2007Jo-Young Suh Abstract Objective: The purpose of this study was to investigate the effects of a nanostructured calcium coating on the surfaces of blasted Ti implants on peri-implant bone formation in the rabbit tibiae. Material and methods: Threaded implants (3.75 mm in diameter, 6 mm in length) were roughened by hydroxyapatite (HA) blasting (control; blasted implants). The implants were then hydrothermally treated in a Ca-containing solution for 24 h to prepare Ca-incorporated Ti surfaces (experimental; blasted/Ca implants). Surface characterizations were performed by scanning electron microscopy and stylus profilometry before and after Ca coating. Forty-two implants (21 control and 21 experimental) were placed in the proximal tibiae of seven New Zealand White rabbits. Each rabbit received six implants. To evaluate the effects of the nanostructured Ca coating on the peri-implant bone-healing response, removal torque tests and histomorphometric analyses were performed 6 weeks after surgery. Results: The Ca coating did not significantly change the surface properties produced by blasting at the micron level. Histologically, active bone apposition was observed in the blasted/Ca implants in the marrow space. Compared with the blasted implants, the blasted/Ca implants showed significantly increased bone-to-implant contact over the total implant length (P<0.01) and greater mean removal torque values (P<0.05). Discussion and conclusion: The nanostructured, Ca-incorporated surface significantly enhanced the peri-implant bone-healing response of HA-blasted Ti implants. It may be concluded that the use of nanostructured, Ca-coated surfaces may have synergic effects in enhancing osseointegration of blasted Ti implants due to their micron-scaled surface properties and biologically active surface chemistry. [source] Osseointegration of Osseotite® and machined-surfaced titanium implants in membrane-covered critical-sized defects: a histologic and histometric study in dogsCLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2007Alexander A. Veis Abstract: The texture of an implant's surface can influence the rate and extent of bone fixation as expressed by the amount of linear bone-to-implant contact (BIC). The purpose of this study was to compare the bone density and linear BIC between Osseotite® and machined-surface implants placed in bony defects without graft material and covered by a membrane. Thirty 2 mm diameter, 10 mm length custom implants were prepared for this study having a ,split surface,' with one side having the acid-etched surface and the opposite side having a machined surface. Defects were created in the iliac wing of three adult mongrel dogs where a 6-mm-diameter drill was used to generate a 5-mm-deep defect. The implants were inserted into the center of the defect with 5 mm secured into the bone leaving 5 mm free in the defect with a 2 mm gap between the implant and surrounding bone. Expanded polytetrafluroethelyene membranes were placed over the defect sites stabilized with Biotack® pins. The healing times were 2, 3, and 5 months. Histologic and histometric analysis showed significantly lower BIC in the defect region as compared with the portion of implant placed into native bone for both implant surfaces in all groups. There was no difference in BIC values at 2- and 5-month periods between the two surfaces in the regenerated area, while BIC values for Osseotite® surfaces were significantly higher than the machined surfaces at 3 months' healing time. Changes in bone density, observed between the three groups, affected correspondingly the BIC values in both implant surfaces, the effect being more pronounced in the Osseotite® surface. [source] Significance of primary stability for osseointegration of dental implantsCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2006Natalia Lioubavina-Hack Abstract Aim: To investigate the significance of the initial stability of dental implants for the establishment of osseointegration in an experimental capsule model for bone augmentation. Material and methods: Sixteen male rats were used in the study. In each rat, muscle-periosteal flaps were elevated on the lateral aspect of the mandibular ramus on both sides, resulting in exposure of the bone surface. Small perforations were then produced in the ramus. A rigid, hemispherical Teflon® capsule with a diameter of 6 mm and a height of 4 mm and with a hole in its middle portion, prepared to fit the circumference of an ITI® HC titanium implant of 2.8 mm in diameter, was fixed to the ramus using 4 mini-screws. On one side of the jaw, the implant was placed through the hole in such a way that its apex did not make contact with the mandibular ramus (test). This placement of the implant did not ensure primary stability. On the other side of the jaw, a similar implant was placed through the hole of the capsule in such a way that contact was made between the implant and the surface of the ramus (control). This provided primary stability of the implant. After placement of the implants, the soft tissues were repositioned over the capsules and sutured. After 1, 3, 6 and 9 months, four animals were sacrificed and subjected to histometric analysis. Results: The mean height of direct bone-to-implant contact of implants with primary stability was 38.8%, 52.9%, 64.6% and 81.3% of the implant length at 1, 3, 6 and 9 months, respectively. Of the bone adjacent to the implant surface, 28.1%, 28.9%, 52.6% and 69.6%, respectively, consisted of mineralized bone. At the test implants, no bone-to-implant contact was observed at any observation time or in any of these non-stabilized specimens. Conclusion: The findings of the present study indicate that primary implant stability is a prerequisite for successful osseointegration, and that implant instability results in fibrous encapsulation, thus confirming previously made clinical observations. [source] Partial generation of periodontal ligament on endosseous dental implants in dogsCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2005Leila Jahangiri Abstract Objectives: The objective of this pilot study was to investigate the feasibility of periodontal ligament (PDL) generation on an implant surface by approximating a tooth-to-implant contact using orthodontics. Methods: Maxillary second premolars of six beagle dogs were extracted bilaterally. After 2 weeks of healing, hydroxyapatite (HA) coated titanium implants, 5 mm in length and 3.3 mm in diameter, were placed in the extraction sites. One side of the arch was used as control. Orthodontic tooth movement was initiated following implant placement to tip the first premolar roots into contact with the implant. This was achieved in 4,6 weeks as confirmed radiographically. Tooth-to-implant contact was maintained for further 6 weeks after which time, teeth were separated from implant contact orthodontically. After further 2 weeks of stabilization, the animals were sacrificed. Samples were analyzed by Faxitron radiographs before histology. Histology samples were prepared with Stevenel's Blue and Van Gieson stain and were subjected to polarized light microscopy. Results: Histologic analysis revealed transfer and formation of PDL-like structure with formation of cellular cementum on the implant surfaces, in four out of six animals, where tooth-to-implant contact had been achieved. Direct bone-to-implant contact was noted in the areas coronal to the PDL-like tissue, an important sign to distinguish between PDL-like tissue and connective tissue that could originate from the coronal portion of a failing implant. Additionally, at the site of contact, the implant surface revealed some resorption of the HA coating. Conclusion: An animal model was established in which the proximity of tooth-to-implant contact lead to partial generation of PDL on a bioactive implant surface in four out of six animals. Résumé L'objectif de cette étude pilote a été d'analyser la possibilité d'obtenir une régénération du ligament parodontal (PDL) sur une surface implantaire en rapprochant le contact implant-dent par l'orthodontie. Les deuxièmes prémolaires maxillaires de six chiens beagle ont été avulsées bilatéralement. Après deux semaines de guérison, des implants en titane recouverts d'hydroxyapatite de 5 mm de long et de 3,3 mm de diamètre ont été insérés dans les sites d'avulsion. Un site de chaque arche était utilisé comme contrôle. Le mouvement orthodontique de la dent était initialisé après le placement de l'implant pour mettre en contact les raçines des premières prémolaires avec l'implant. Ceci a été réalisé en quatre à huit semaines comme l'a confirmé la radiographie. Le contact dent-implant a été maintenu pour une durée supplémentaire de six semaines après lesquelles les dents ont été séparées du contact des implants de manière orthodontique. Après deux semaines de stabilisation, les animaux ont été euthanasiés. Les échantillons ont été analysés par radiographie Faxitron avant l'histologie. Les échantillons histologiques ont été préparés par les colorations du Bleu de Stevenel et de Van Gieson et ont été analysés au microscope optique à polarisation. L'histologiea révélé un transfert et une formation d'une structure ressemblant à PDL avec la formation d'un cément cellulaire à la surface des implants chez quatre des six animaux chez lesquels le contact dent-implant avaient été réalisés. Le contact direct os-implant a été noté dans les zones coronaires au tissu qui ressemblait à PDL, un signe important pour distinguer le tissu ressemblant à PDL et le tissu conjonctif qui pouvait provenir de la portion coronaire de l'implant qui échoue. De plus, au site de contact, la surface implantaire révélait quelques résorptions du recouvrement d'hydroxyapatite. Un modèle animal a donc étéétabli dans lequel la proximité du contact dent-implant était suivie d'une génération partielle de PDL sur une surface implantaire bioactive chez quatre des six animaux. Zusammenfassung Ziele: Das Ziel dieser Pilotstudie war, zu untersuchen, ob es möglich sei, ein parodontales Ligament (PDL) auf einer Implantatoberfläche durch Herstellung eines Zahn-Implantat-Kontakts mittels Orthodontie zu generieren. Methoden: Bei sechs Beagle-Hunden wurden bilateral die zweiten Prämolaren extrahiert. Nach einer Abheilzeit von zwei Wochen wurden Hydroxyapatit beschichtete Titanimplantate mit einer Länge von 5 mm und einem Durchmesser von 3.3 mm in die Extraktionsstellen eingesetzt. Eine Seite des Zahnbogens diente als Kontrolle. Nach der Implantatplatzierung wurde mit der orthodontischen Zahnbewegung begonnen, um die Wurzeln der ersten Prämolaren in Kontakt mit den Implantaten zu bringen. Es wurde radiologisch bestätigt, dass dies nach 4,6 Wochen erreicht wurde. Der Zahn-Implantat-Kontakt wurde für weitere sechs Wochen belassen, danach wurden die Zähne wieder orthodontisch vom Kontakt mit den Implantaten separiert. Nach weiteren zwei Wochen zur Stabilisierung wurden die Tiere geopfert. Die Proben wurden vor der Histologie mittels Faxitron Röntgen analysiert. Die histologischen Proben wurden mit Stevenel`s Blau und van Gieson Färbungen bearbeitet und durch Lichtmikroskopie mit polarisiertem Licht untersucht. Resultate: Die histologische Analyse zeigte einen Transfer und eine Formation von Parodontalligament ähnlichen Strukturen mit der Bildung von zellulärem Zement auf der Implantatoberfläche bei 4 von 6 Tieren, bei welchen ein Zahn-Implantat-Kontakt erreicht worden war. Koronal des PDL-ähnlichen Gewebes bestand ein direkter Knochen-Implantat-Kontakt. Dies war ein wichtiges Merkmal, um zwischen PDL-ähnlichem Gewebe und Bindegewebe, welches vom koronalen Anteil eines fehlgeschlagenen Implantats stammen könnte, zu unterscheiden. Zusätzlich zeigten die Implantatoberflächen im Bereich der Berührungsfläche etwas Resorption der Hydroxyapatit Beschichtung. Schlussfolgerung: Es wurde ein Tiermodell etabliert, in welchem ein Zahn-Implantat-Kontakt bei 4 von 6 Tieren zu einer partiellen Generation eines PDL auf einer bioaktiven Implantatoberfläche führte. Resumen Objetivos: El objetivo de este estudio piloto fue investigar la viabilidad de generación de ligamento periodontal (PDL) en la superficie de un implante por aproximación de un contacto diente a implante usando ortodoncia. Métodos: Se extrajeron los segundos premolares de seis perros beagle bilateralmente. Tras dos semanas de cicatrización, se colocaron en los lugares de extracción implantes de titanio cubiertos de hidroxiapatita, de 5 mm de longitud y 3.3 mm de diámetro. Un lado del arco se usó como control. El movimiento dental ortodóntico se inició tras la colocación del implante para apuntar las raíces del primer premolar hacia el contacto con el implante. Esto se logró en 4-6 semanas tal como se confirmó radiograficamente. El contacto diente a implante se mantuvo durante seis semanas mas tras lo cual, los dientes se separaron del contacto con el implante ortodonticamente. Tras dos semanas más de estabilización, los animales se sacrificaron. Las muestras se analizaron por medio de radiografías Faxitron antes de la histología. Las muestras histológicas se prepararon con azul de Stevenel y tinción de Van Gieson y se sometieron a microscopio de luz polarizada. Resultados: El análisis histológico reveló transferencia y formación de estructuras tipo ligamento periodontal con formación de cemento celular en las superficies del implante, en 4 de 6 animales, en los que se logró el contacto diente a implante. Se notó contacto en las áreas coronales al tejido tipo PDL, un signo importante para distinguir tejido tipo PDL y tejido conectivo que se podría originar de la parte coronal de un implante en vías de fracaso. Además, en el lugar del contacto, la superficie del implante reveló algo de reabsorción de la cubierta de hidroxiapatita. Conclusión: Se estableció un modelo animal en el que la proximidad del contacto diente a implante llevó a la generación parcial de PDL en una superficie de implante bioactiva en 4 de 6 animales. [source] Anorganic porous bovine-derived bone mineral (Bio-Oss®) and ePTFE membrane in the treatment of peri-implantitis in cynomolgus monkeysCLINICAL ORAL IMPLANTS RESEARCH, Issue 5 2003Søren Schou Abstract: The purpose of the present study was to evaluate the effect of anorganic porous bovine-derived bone mineral (Bio-Oss®) and expanded polytetrafluoroethylene (ePTFE) membrane in the treatment of peri-implantitis. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was inserted in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month healing period with plaque control, experimental peri-implantitis characterized by a bone loss of 4,6 mm was induced during a period of 9,18 months. Surgical treatment involving Bio-Oss+membrane, Bio-Oss, membrane, or a conventional flap procedure (control) only was carried out. The animals were sacrificed six months after treatment. Evaluation by clinical parameters, radiography including quantitative digital subtraction radiography, histology, and stereology demonstrated healthy peri-implant tissue irrespective of the applied surgical procedure. However, the amount of re-osseointegration and the total amount of bone (Bio-Oss and regenerated bone) were significantly higher in defects treated with membrane-covered Bio-Oss as compared with the other three treatment procedures. A mean bone-to-implant contact of 36% was obtained within defects treated with membrane-covered Bio-Oss. The corresponding values for the three other treatment procedures were 13,23%. The Bio-Oss particles were in general highly integrated within the regenerated bone, but the particles in the occlusal part of the defects were entirely surrounded by connective tissue irrespective of membrane coverage. The present study demonstrates that surgical treatment involving Bio-Oss covered by an ePTFE membrane is a useful treatment modality of experimental peri-implantitis around implants with a TPS surface in cynomolgus monkeys. However, the treatment outcome is not as encouraging as seen with membrane-covered autogenous bone graft particles documented in a study with same experimental design. Résumé Le but de l'étude présente a été d'évaluer l'effet d'un minéral osseux bovin poreux et anorganique (Bio-Oss®) et d'une membrane en téflon lors du traitement de la paroïmplantite. Soixante-quatre implants avec une surface plasma-spray en titane (TPS) ont été insérés chez huit singes Macaca fascicularis. Après une période de guérison de trois mois avec contrôle de la plaque dentaire, une paroïmplantite expérimentale caractérisée par une perte osseuse de 4 à 6 mm a été induite pendant une période de 9 à 18 mois. Le traitement chirurgical comprenant le Bio-Oss® et la membrane, le Bio-Oss®, la membrane, ou un processus de lambeau conventionnel (contrôle) ont été effectués. Les animaux ont été tués six mois après le traitement. L'évaluation par les paramètres cliniques, la radiographie incluant la radiographie de soustraction, l'histologie et la stéréologie ont mis en évidence des tissus paroïmplantaires sains quel que soit le processus chirurgical utilisé. Cependant la quantité de ré-ostéoïntégration et la quantité totale d'os (Bio-Oss®+ os régénéré) étaient significativement plus importantes dans les lésions traitées par Bio-Oss® recouvert de membrane comparée aux trois autres processus chirurgicaux. Un contact moyen os-implant de 36% a été obtenu à l'intérieure d'une lésion traitée par Bio-Oss® recouvert par une membrane. Les valeurs correspondantes pour les trois autres processus s'étalaient de 13 à 23%. Les particules de Bio-Oss®étaient en général très bien intégrées dans l'os régénéré, mais les particules dans la partie occlusale des lésions étaient entièrement entourées par du tissu conjonctif qu'il y ait ou non recouvrement par une membrane. Cette étude démontre que le traitement chirurgical impliquant le Bio-Oss® recouvert par une membrane en téflon est une modalité de traitement utile de la paroïmplantite autour des implants avec une surface TPS chez le Macaca fascicularis. Cependant le traitement n'est pas aussi encourageant que celui aperçu avec des greffes de particules d'os autogène recouvertes par une membrane qui avait été mis en évidence dans une étude utilisant le même modèle expérimental. Zusammenfassung Das Ziel der vorliegenden Studie war, den Effekt von anorganischem porösem bovinem Knochenmineral (Bio-Oss®) und expandiertem Polytetrafluoroethylene (ePTFE)-Membranen bei der Behandlung von Peri-Implantitis zu untersuchen. Insgesamt wurden 64 Implantate mit einer titanplasmabeschichteten Oberfläche (TPS) bei 8 Cynomolgus Affen (Macaca fascicularis) eingesetzt. Nach einer Heilungszeit von 3 Monaten mit Plaquekontrolle wurde eine experimentelle Peri-Implantitis, charakterisiert durch einen Knochenverlust von 4-6mm, über einen Zeitraum von 9 bis 18 Monaten induziert. Folgende chirurgische Massnahmen wurden durchgeführt: Bio-Oss+Membran, Bio-Oss, Membran oder konventionelle Lappenchirurgie (Kontrolle). Die Tiere wurden 6 Monate nach der Behandlung geopfert. Die Untersuchung mittels klinischer Parameter, Radiographie inklusive quantitative digitale Subtraktionsradiographie, Histologie und Stereologie zeigte gesunde peri-implantäre Gewebe, egal welche chirurgische Massnahme angewendet wurde. Jedoch war das Ausmass der Re-Osseointegration und die totale Menge an Knochen (Bio-Oss und regenerierter Knochen) bei den Defekten, welche mit Bio-Oss und Membran behandelt worden waren, signifikant grösser als bei den drei anderen Behandlungsgruppen. Bei den Defekten, welche mit Membran und Bio-Oss behandelt wurden, konnte ein Knochen-Implantat-Kontakt von 36% erreicht werden. Die entsprechenden Werte für die drei anderen Behandlungsgruppen betrugen 13-23%. Die Bio-Oss Partikel waren generell gut in den regenerierten Knochen integriert, nur die Partikel im okklusalen Bereich der Defekte waren komplett von Bindegewebe umgeben, egal ob sie mit einer Membran abgedeckt waren oder nicht. Die vorliegende Studie demonstriert, dass die chirurgischen Behandlung mit Bio-Oss, welches mit einer ePTFE-Membran bedeckt wird, eine brauchbare Behandlungsmodalität für die experimentelle Peri-Implantitis um Implantate mit TPS-Oberfläche bei Cynomolgus Affen darstellt. Jedoch sind die Behandlungsresltate nicht so ermutigend wie die Resultate einer anderen Studie mit demselben experimentellen Aufbau, bei der autologe Knochenpartikel mit Membranen bedeckt wurden. Resumen El propósito del presente estudio fue evaluar el efecto de mineral derivado bovino anorgánico poroso (Bio-Oss®) y membrana de politetrafluoroetileno expandido (ePTFE) en el tratamiento de periimplantitis. Se insertaron un total de 64 implantes con una superficie pulverizada con plasma de titanio (TPS) en 8 monos cynomolgus (Macaca fascicularis). Tras 3 meses de periodo de cicatrización con control de placa, se indujo una periimplantitis experimental caracterizada por una perdida ósea de 4-6 mm durante un periodo de 9-18 meses. Se llevó a cabo un tratamiento quirúrgico consistente en Bio-Oss+membrana, Bio-Oss, membrana, o un procedimiento de colgajo convencional (control). La evaluación por parámetros clínicos, radiográficos incluyendo radiografías digitales de sustracción cuantitativa, histología, y estereología demostraron tejidos periimplantarios sanos irrespectivamente del procedimiento quirúrgico aplicado. De todos modos, la cantidad de re-osteointegración y la cantidad total de hueso (Bio-Oss y hueso regenerado) fueron significativamente mayores en los defectos tratados con Bio-Oss cubiertos por membrana comparados con los otros 3 procedimientos terapéuticos. Se obtuvo un contacto hueso implante del 36 % dentro de los defectos tratados con Bio-Oss cubierto por membrana. Los valores correspondientes para los otros 3 procedimientos terapéuticos fueron del 13-23 %. Las partículas de Bio-Oss se integraron altamente en general con el hueso regenerado, pero las partículas en la parte oclusal de los defectos estaban enteramente rodeadas de tejido conectivo irrespectivamente de cobertura de membrana. El presente estudio demuestra que el tratamiento quirúrgico que incluye Bio-Oss cubierto por una membrana de ePTFE es una modalidad de tratamiento de la periimplantitis experimental alrededor de los implantes con una superficie TPS en monos cynomolgus. De todos modos, los resultados del tratamiento no son tan alentadores como los observados con partículas de hueso autógeno documentados en un estudio con el mismo diseño experimental. [source] Long-term effects of magnetron-sputtered calcium phosphate coating on osseointegration of dental implants in non-human primatesCLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2009Fügl Alexander Abstract Objectives: To determine the effect of magnetron-sputtered calcium phosphate coating of implants on the later stages of osseointegration in a non-human primate model. Material and methods: Eighteen and 20 implants with a 0.1 ,m amorphous calcium phosphate coating and a turned surface, respectively, were inserted in the anterior upper and lower jaw of adult non-human primates. Following a 7.5 months healing period, one part of the implants remained in the submerged position. The other part of implants was connected to healing abutments to allow peri-implant inflammation to occur. After another 20 months, histologic and histomorphometric analysis of the peri-implant area was performed. Results: Submerged implants with a calcium phosphate coating and a turned surface showed no signs of an inflammatory reaction. The histomorphometric parameters ,bone volume per tissue volume' (BV/TV) and ,bone-to-implant contacts' (BIC) were not affected by calcium phosphate coating. Non-submerged implants of both groups showed occasionally signs of inflammation at the implant,abutment junction. Histomorphometric analysis revealed that the distance between the implant,abutment junction and the most coronal level (where bone was attached to the implant) as well as BV/TV and BIC were independent from the surface modification. Conclusion: Our results show that dental implants with calcium phosphate coating behave similar to turned implants independently whether they are connected to healing abutments or remain submerged. Ultra-thin calcium phosphate coating can combine the positive effects of calcium phosphate during the early stage of osseointegration without causing impairment of the later stages. [source]
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