| 1. |
- 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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| 2. |
- Dahlin, Christer, 1959, et al.
(författare)
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Generation of new bone around titanium implants using a membrane technique: an experimental study in rabbits.
- 1989
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Ingår i: The International journal of oral & maxillofacial implants. - 0882-2786. ; 4:1, s. 19-25
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Tidskriftsartikel (refereegranskat)abstract
- Insufficient bone volume may be a significant problem in connection with dental implants. In this study, a technique based on the principle of guided tissue regeneration was tested for its ability to generate bone tissue around titanium implants. Implants were inserted in tibiae of rabbits. To create a secluded space for osteogenesis and to prevent soft-tissue ingrowth, a porous Teflon membrane was placed around exposed parts of the implant. Where a membrane had been used, the threads of the implant were completely covered with significant amounts of new bone. This study indicates that the membrane technique is a reconstructive surgical method that may be applicable to create new bone around exposed parts of titanium implants in a clinical setting.
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| 3. |
- Johansson, Lars-Åke, 1950, et al.
(författare)
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Evaluation of bone regeneration after three different lateral sinus elevation procedures using micro-computed tomography of retrieved experimental implants and surrounding bone: a clinical, prospective, and randomized study.
- 2013
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Ingår i: The International journal of oral & maxillofacial implants. - : Quintessence Publishing. - 1942-4434 .- 0882-2786. ; 28:2, s. 579-86
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Tidskriftsartikel (refereegranskat)abstract
- To compare three different lateral sinus elevation procedures concerning new bone formation by using micro–computed tomography (micro-CT) of retrieved implants. Materials and Methods: Twenty-four consecutive partially dentate patients with a mean age of 64 years were included in the study and provided with 30 sinus elevation procedures. Three procedures for lateral sinus elevation were used: lateral sinus elevation with replacement of bone window and without bone graft (BW), lateral sinus elevation and covering osteotomy site with a collagen membrane and without bone graft (CM), and lateral sinus elevation with autogenous bone graft (ABG). Experimental implants were retrieved after 7 months of healing and analyzed by micro-CT. Results: One implant was found not to be integrated at the time of implant retrieval. This implant belonged to group CM and was excluded when calculating bone-to-implant contact (BIC) and intrasinus bone levels. The integrity of the lateral sinus bony wall was determined at the time of implant removal. In group ABG, all lateral sinus walls were ossified. In group BW, one lateral sinus wall was not completely ossified and in group CM, two lateral sinus walls. There were no statistical differences in %BIC between the groups: 93.5% (BW), 92.0% (CM) and 93.5% (ABG). Additionally, no statistical differences were found in apical intrasinus bone levels between the groups. When surfaces were compared within the same implant, a statistical difference was found between the apicobuccal distance and the apicolingual distance. The mean apicobuccal distances/apicolingual distances were 0.6 mm/1.2 mm for the BW group, 0.5 mm/0.8 mm for the CM group, and 0.6 mm/0.8 mm for the ABG group (P = .003). Conclusions: All three procedures were statistically equal when new bone formation was compared. Most of the examined implants’ apices were not covered with bone at the time of retrieval.
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| 4. |
- Nyberg, Jan, 1960-, et al.
(författare)
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Molecular Activity and Osseointegration After Single-Dose Irradiation: An In Vivo Study
- 2017
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Ingår i: International Journal of Oral & Maxillofacial Implants. - : Quintessence Publishing. - 0882-2786 .- 1942-4434. ; 32:5, s. 1033-1038
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Irradiation results in deleterious effects on bone healing and integration of titanium implants. The impact of irradiation on osseointegration has been demonstrated in histologic studies, but the underlying molecular mechanisms have not been explored. This study aimed to investigate the effects of single-dose irradiation on the expression of biologic mediators crucial for inflammation, bone formation, and bone remodeling and to relate these molecular activities to implant stability after a 5-week healing period. Materials and Methods: A rat tibia model was used. An external single-dose irradiation of 20 Gy was administered to one leg while the second leg was used as a control. After 8 weeks, the irradiated and non-irradiated tibiae received titanium implants. Five weeks following implantation, implant stability was evaluated by removal torque measurement. Then, the implant and the bone surrounding the implant were retrieved for gene expression analysis of the implant-adherent cells and peri-implant bone, respectively. Results: Irradiation resulted in 55% reduction in removal torque. The implant-adherent cells in irradiated sites revealed downregulation of genes related to bone formation (ALP and OC) and upregulation of pro-inflammatory (TNF-alpha) and pro-fibrogenic (PDGF-b) genes. Conversely, the peri-implant bone in irradiated sites revealed upregulation of bone formation and bone remodeling genes. Removal torque showed a negative correlation with pro-inflammatory activity and a positive correlation with osteoblastic activity in the implant-adherent cells. Conclusion: The impact of high (20 Gy) single-dose irradiation on osseointegration involves a reduction in bone formation activity and upregulation of pro-inflammatory and pro-fibrogenic activities in the implant-adherent cells. It is also suggested that this single-dose irradiation elicits a different molecular pattern at a distance from the implant surface, characterized by increased bone formation and remodeling activities in the peri-implant bone.
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