| 1. |
- Aludden, H., et al.
(författare)
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Histomorphometric analyses of area fraction of different ratios of Bio-Oss((R)) and bone prior to grafting procedures - An in vitro study to demonstrate a baseline
- 2018
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Ingår i: Clinical Oral Implants Research. - : Wiley. - 0905-7161 .- 1600-0501. ; 29:2, s. 185-191
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveThe objective of this study was to estimate the area fraction of different ratios of Bio-Oss((R)) and bone, prior to grafting in an in vitro model to demonstrate a histomorphometric baseline. MethodsBio-Oss((R)) particles were mixed with autogenous bone from pig jaw in three different ratios (50:50, 80:20 and 100:0) and packed in rice paper in a standardized procedure. Histomorphometric analyses were performed in 25 specimens and 74 regions of interest. The area percentage of Bio-Oss((R)), bone, and non-mineralized tissue (NMT) were calculated. Results were reported as mean values and 95% confidence interval (CI). ResultsThe mean area fraction of Bio-Oss((R)) was 20.6% (CI: 18.2-23) in the 50:50 mixture, 33.6% (CI: 29.7-37.6) in the 80:20 mixture, and 43.4% (CI: 40.5-46.3) in the 100:0 mixture. The mean area fraction of NMT was 60.5% (CI: 57.9-63.1) in the 50:50 mixture, 59.6% (CI: 56.4-62.7) in the 80:20 mixture, and 56.6% (CI: 53.7-59.5) in the 100:0 mixture. The mean area fraction of bone was 18.9% (CI: 16.9-20.9) in the 50:50 mixture and 6.8% (CI: 5-8.6) in the 80:20 mixture. ConclusionThere is a great difference in the clinically estimated percentage and the histomorphometrically evaluated percentage of Bio-Oss((R)) at baseline, prior to grafting. The area fraction of different tissues presented in this study may be beneficial as guidance for histomorphometrical baseline calculations when different mixtures of Bio-Oss((R)) and autogenous bone are used as grafting materials.
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| 2. |
- Farzad, Payam, 1973, et al.
(författare)
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Integration of dental implants in conjunction with edta-conditioned dentin grafts: An experimental study
- 2021
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Ingår i: Dentistry Journal. - : MDPI AG. - 2304-6767. ; 9:6
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Tidskriftsartikel (refereegranskat)abstract
- This study was undertaken to investigate the integration of titanium micro-implants installed in conjunction with previously dentin-grafted areas and to study the morphological appearance, mineral content, and healing pattern of xenogenic EDTA-conditioned dentin blocks and granules grafted to cavities in the tibial bone of rabbits. Demineralized and non-demineralized dentin blocks and granules from human premolars were implanted into cavities prepared on the lateral aspects of the tibias of rabbits. After a healing period of six months, micro-implants were installed at each surgical site. Histological examinations were carried out after 24 weeks. Characterization of the EDTA-conditioned dentin blocks was performed by means of light microscopy, dental X-rays, scanning electron microscopy, and energy dispersive X-ray analysis (EDX). No implants were found to be integrated in direct contact with the dentin particles or blocks. On the EDTA-conditioned dentin surface, the organic marker elements C and N dominated, as revealed by EDX. The hydroxyapatite constituents Ca and P were almost absent on the dentin surface. No statistically significant difference was observed between the EDTA-conditioned and non-demineralized dentin, as revealed by BIC and BA. The bone-inductive capacity of the dentin material seemed limited, although demineralization by means of EDTA indicated higher BIC and BA values in conjunction with the installed implants in the area. A 12 h EDTA treatment did not fully decalcify the grafts, as revealed by X-ray analysis. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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| 3. |
- Omar, Omar, et al.
(författare)
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Tissue dynamics and regenerative outcome in two resorbable non-cross-linked collagen membranes for guided bone regeneration: A preclinical molecular and histological study in vivo
- 2018
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Ingår i: Clinical Oral Implants Research. - : Wiley. - 0905-7161. ; 29:1, s. 7-19
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To investigate the molecular and structural patterns of bone healing during guided bone regeneration (GBR), comparing two resorbable non-cross-linked collagen membranes. Materials and methods: Trabecular bone defects in rat femurs were filled with deproteinized bovine bone (DBB) and covered with either a membrane comprising collagen and elastin (CXP) or collagen (BG). Samples were harvested after 3 and 21 days for histology/histomorphometry and gene expression analysis. Gene expression analysis was performed on the membrane (at 3 days) and the underlying defect compartment (at 3 and 21 days). Results: At the total defect level, no differences in bone area percentage were found between the CXP and BG. When evaluating the central area of the defect, a higher percentage of de novo bone formation was seen for the CXP membrane (34.9%) compared to BG (15.5%) at 21 days (p = .01). Gene expression analysis revealed higher expression of bone morphogenetic protein-2 (Bmp2) in the membrane compartment at 3 days in the BG group. By contrast, higher Bmp2 expression was found in the defect compartment treated with the CXP membrane, both at 3 and 21 days. A significant temporal increase (from 3 to 21 days) in the remodeling activity, cathepsin K (Catk) and calcitonin receptor (Calcr), was found in the CXP group. Molecular analysis demonstrated expression of several growth factors and cytokines in the membrane compartment irrespective of the membrane type. Bmp2 expression in the membrane correlated positively with Bmp2 expression in the defect, whereas fibroblast growth factor-2 (Fgf2) expression in the membrane correlated positively with inflammatory cytokines, tumor necrosis factor-alpha (Tnfa) and interleukin-6 (II6) in the defect. Conclusions: The results provide histological and molecular evidence that different resorbable collagen membranes contribute differently to the GBR healing process. In the BG group, bone formation was primarily localized to the peripheral part of the defect. By contrast, the CXP group demonstrated significantly higher de novo bone formation in the central portion of the defect. This increase in bone formation was reflected by triggered expression of potent osteogenic growth factor, Bmp2, in the defect. These findings suggest that the CXP membrane may have a more active role in regulating the bone healing dynamics.
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| 4. |
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| 5. |
- Al-Asfour, Adel, et al.
(författare)
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Demineralized Xenogenic Dentin and Autogenous Bone as Onlay Grafts to Rabbit Tibia.
- 2017
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Ingår i: Implant dentistry. - 1538-2982. ; 26:2, s. 232-237
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Tidskriftsartikel (refereegranskat)abstract
- The present study was undertaken to evaluate the healing pattern of xenogenic demineralized dentin onlay grafts in comparison with autogenous bone grafts to the rabbit tibia.Eight 6-month-old New Zealand male rabbits were used in the experiments. Standardized sized dentin blocks from human premolars and similar autogenous bone blocks harvested from tibia were grafted as onlay blocks on each tibia (n = 8 × 2). All animals were killed after a healing period of 12 weeks.Healing was uneventful for all animals. In general, both the dentin and bone block grafts were fused to the bone, resorbed, and replaced by bone and connective tissue to a varying degree. Both types of grafts were still present after 12 weeks, on an average to approximately one third of the original sizes. Resorption cavities could be seen in the dentin with bone formation. Zones of osseous replacement resorption of the dentin could be noted. In both graft types, higher rate of bone formation was seen at the interface between graft and recipient site.Demineralized xenogenic dentin onlay grafts showed similar resorption characteristics as autogenous bone onlay grafts, being resorbed in a similar rate during 12 weeks. New bone formation occurred mainly in terms of replacement resorption in the interface between dentin/bone graft and native bone.
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| 6. |
- Al-Asfour, Adel, et al.
(författare)
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Histologic analysis of a novel extracellullar matrix membrane for guided bone regeneration: an experimental study in rabbits.
- 2013
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Ingår i: The International journal of periodontics & restorative dentistry. - : Quintessence Publishing. - 1945-3388 .- 0198-7569. ; 33:2, s. 177-83
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Tidskriftsartikel (refereegranskat)abstract
- This experiment was conducted to study the histologic feasibility and biologic impact of Ti02 impregnation of an extracellullar matrix (ECM) membrane in guided bone regeneration. Eighteen adult New Zealand White rabbits were used. Bilateral bone defects were created in edentulous areas of the maxilla. The defects were filled with demineralized freeze-dried bone (DFDB). ECM was randomly pretreated with a suspension containing saline and 3 mg Ti02 granules. A regular ECM membrane served as a control on the contralateral side. Healing periods were 2, 4, and 8 weeks. Histologic and histomorphometric analyses were performed. The parameters assessed were (1) zone of inflammatory cells adjacent to ECM membrane, (2) presence of cellullar ingrowth into ECM, and (3) presence of Ti02 particles within the ECM barrier membrane. In general, no adverse reactions toward both groups of ECM membranes could be noted. The Ti02 particles remained within the ECM after 8 weeks of healing, making histologic detection of ECM easy. Histomorphometric analysis revealed low numbers of inflammatory cells adjacent to the ECM surface and adequate preservation and integration of the barrier. Contrasting Ti02 particles impregnated into the ECM membrane can be a very useful tool for the detection of similar biologic materials in in vivo models.
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| 7. |
- Al-Asfour, Adel, et al.
(författare)
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Host tissue reactions of non-demineralized autogenic and xenogenic dentin blocks implanted in a non-osteogenic environment. An experimental study in rabbits.
- 2014
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Ingår i: Dental traumatology : official publication of International Association for Dental Traumatology. - : Wiley. - 1600-9657. ; 30:3, s. 198-203
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Tidskriftsartikel (refereegranskat)abstract
- Dentoalveolar ankylosis with osseous replacement is often seen after replantation of avulsed teeth, and this process may be used for preservation of alveolar crests after trauma. Its exact mechanisms with regard to osteoinductive properties are not yet fully understood and need to be systematically investigated. Dentin can possibly act as a slow-releasing carrier of bone morphogenic proteins (BMP), and this property of dentin has been proposed to be used as an alternative or supplement to bone grafting in the maxillofacial region. We aimed to initially asses host tissue reactions to dentin by implanting dentin blocks of autogenic and xenogenic human origin in rabbit connective tissue of the abdominal wall and femoral muscle. Animals were sacrificed after a period of 3months, and histological processing, sectioning and examinations were carried out. Bone formation, cell counts and thickness of capsule surrounding the grafts were evaluated. Only minor signs of heterotopic bone formation were seen. There were no significant differences between autografts and xenografts or grafts implanted in connective tissue or muscle with regards to tissue reactions except for a significant difference (P=0.018) in findings of more local inflammatory cells in relation to grafts placed in connective tissue in the autograft group. We conclude that during the time frame of this study, non-demineralized dentin, whether autogenous or xenogenic did not have the potential to induce bone formation when implanted in non-osteogenic areas such as the abdominal wall and abdominal muscle of rabbits.
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| 8. |
- Albrektsson, Tomas, 1945, et al.
(författare)
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An Imbalance of the Immune System Instead of a Disease Behind Marginal Bone Loss Around Oral Implants: Position Paper
- 2020
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Ingår i: The International journal of oral & maxillofacial implants. - : Quintessence Publishing. - 1942-4434 .- 0882-2786. ; 35:3, s. 495-502
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The purpose of this paper is to present evidence that supports the notion that the primary reason behind marginal bone loss and implant failure is immune-based and that bacterial actions in the great majority of problematic cases are of a secondary nature. MATERIALS AND METHODS: The paper is written as a narrative review. RESULTS: Evidence is presented that commercially pure titanium is not biologically inert, but instead activates the innate immune system of the body. For its function, the clinical implant is dependent on an immune/inflammatory defense against bacteria. Biologic models such as ligature studies have incorrectly assumed that the primary response causing marginal bone loss is due to bacterial action. In reality, bacterial actions are secondary to an imbalance of the innate immune system caused by the combination of titanium implants and ligatures, ie, nonself. This immunologic imbalance may lead to marginal bone resorption even in the absence of bacteria. CONCLUSION: Marginal bone loss and imminent oral implant failure cannot be properly analyzed without a clear understanding of immunologically caused tissue responses.
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| 9. |
- Albrektsson, Tomas, et al.
(författare)
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Is Marginal Bone Loss around Oral Implants the Result of a Provoked Foreign Body Reaction?
- 2014
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Ingår i: Clinical Implant Dentistry and Related Research. - : John Wiley & Sons. - 1523-0899 .- 1708-8208. ; 16:2, s. 155-165
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Tidskriftsartikel (refereegranskat)abstract
- Background When a foreign body is placed in bone or soft tissue, an inflammatory reaction inevitably develops. Hence, osseointegration is but a foreign body response to the implant, which according to classic pathology is a chronic inflammatory response and characterized by bone embedding/separation of the implant from the body. Purpose The aim of this paper is to suggest an alternative way of looking at the reason for marginal bone loss as a complication to treatment rather than a disease process. Materials and Methods The present paper is authored as a narrative review contribution. Results The implant-enveloping bone has sparse blood circulation and is lacking proper innervation in clear contrast to natural teeth that are anchored in bone by a periodontal ligament rich in blood vessels and nerves. Fortunately, a balanced, steady state situation of the inevitable foreign body response will be established for the great majority of implants, seen as maintained osseointegration with no or only very little marginal bone loss. Marginal bone resorption around the implant is the result of different tissue reactions coupled to the foreign body response and is not primarily related to biofilm-mediated infectious processes as in the pathogenesis of periodontitis around teeth. This means that initial marginal bone resorption around implants represents a reaction to treatment and is not at all a disease process. There is clear evidence that the initial foreign body response to the implant can be sustained and aggravated by various factors related to implant hardware, patient characteristics, surgical and/or prosthodontic mishaps, which may lead to significant marginal bone loss and possibly to implant failure. Admittedly, once severe marginal bone loss has developed, a secondary biofilm-mediated infection may follow as a complication to the already established bone loss. Conclusions The present authors regard researchers seeing marginal bone loss as a periodontitis-like disease to be on the wrong track; the onset of marginal bone loss around oral implants depends in reality on a dis-balanced foreign body response.
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| 10. |
- Aludden, H. C., et al.
(författare)
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Lateral ridge augmentation with Bio-Oss alone or Bio-Oss mixed with particulate autogenous bone graft: a systematic review
- 2017
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Ingår i: International Journal of Oral and Maxillofacial Surgery. - : Elsevier BV. - 0901-5027. ; 46:8, s. 1030-1038
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this systematic review was to test the hypothesis of no difference in implant treatment outcomes when using Bio-Oss alone or Bio-Oss mixed with particulate autogenous bone grafts for lateral ridge augmentation. A search of the MEDLINE, Cochrane Library, and Embase databases in combination with a hand-search of relevant journals was conducted. Human studies published in English from 1 January 1990 to 1 May 2016 were included. The search provided 337 titles and six studies fulfilled the inclusion criteria. Considerable variation prevented a meta-analysis from being performed. The two treatment modalities have never been compared within the same study. Non-comparative studies demonstrated a 3-year implant survival of 96% with 50% Bio-Oss mixed with 50% autogenous bone graft. Moreover, Bio-Oss alone or Bio-Oss mixed with autogenous bone graft seems to increase the amount of newly formed bone as well as the width of the alveolar process. Within the limitations of this systematic review, lateral ridge augmentation with Bio-Oss alone or in combination with autogenous bone graft seems to induce newly formed bone and increase the width of the alveolar process, with high short-term implant survival. However, long-term studies comparing the two treatment modalities are needed before final conclusions can be drawn.
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