Osseointegration of SLActive implants in diabetic pigs
Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany. Clinical Oral Implants Research
(Impact Factor: 3.89).
11/2011; 24(2). DOI: 10.1111/j.1600-0501.2011.02380.x
Diabetes mellitus is currently classified as a relative contraindication for implant treatment because of microangiopathies with the consequence of impaired bone regeneration and higher rates of implant failure. The study aim was to investigate peri-implant bone formation in a diabetic animal model in comparison to healthy animals and to evaluate the differences between conventional (SLA®) and modified (SLActive®) titanium implant surfaces on osseointegration.
Each six implants were placed in the calvaria of 11 diabetic and 4 healthy domestic pigs. At 30 and 90 days after implant placement, the bone-to-implant contact (BIC) and bone density (BD) were appraised. Additionally, the expression of the bone-matrix proteins collagen type I and osteocalcin was evaluated at both points in time by using immunohistochemical staining methods.
Overall, BIC was reduced in the diabetic group at 30 and 90 days. After 90 days, the SLActive® implants showed significantly higher BICs compared with the SLA® implants in diabetic animals. Peri-implant BD was higher in the SLActive® group at 30 and 90 days in healthy and diabetic animals. Collagen type I protein expression was higher using SLA® implants in diabetic pigs at 30 days. Values for osteocalcin expression were not consistent.
The results indicate the negative effect of untreated diabetes mellitus on early osseointegration of dental implants. The modified SLA® surface (SLActive®) elicited an accelerated osseointegration of dental implants, suggesting that a better prognosis for implant treatment of diabetic patients is possible.
Available from: Peer W Kaemmerer
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Osteoconductive characteristics of different implant surface coatings are in the focus of current interest. The aim of the present study was to compare the vertical osteoconductivity at the implant shoulder of supracrestal inserted calcium-phosphate coated implants (SLA-CaP) with conventional sand-blasted/acid-etched (SLA) implants in a rabbit model.
Materials and methods:
SLA-CaP and SLA implants were inserted bilaterally in the mandible of four rabbits in a split-mouth design. The implants were placed 2 mm supracrestal. After 3 weeks, at the left and right implant shoulder, the percentage of linear bone fill (PLF) as well as bone-implant contact (BIC-D) were determined.
After 3 weeks, newly formed woven bone could be found at the shoulder of the most of both surface-treated implants (75%). PLF was significantly higher in SLA-CaP implants (11.2% vs. 46.5%; n = 8, p = .008). BIC-D was significantly increased in the SLA-CaP implants (13.0% vs. 71.4%; n = 8, p < .001) as well.
The results of this study show for the first time that calcium-phosphate coated surfaces on supracrestal inserted implants have vertical osteoconductive characteristics and increase the bone-implant contact at the implant shoulder significantly in a rabbit model. In clinical long-term settings, these implants may contribute to a better vertical bone height.
Available from: Seiichi Yamano
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ABSTRACT: BACKGROUND: Healing of tooth extraction sockets in poorly controlled diabetic patients is often delayed and accompanied by severe infection. The exact cellular and molecular mechanisms underlying the pathogenesis of this complication are still not fully understood. OBJECTIVES: The purpose of this study was to investigate molecular changes associated with delayed oral wound healing in diabetes. MATERIALS AND METHODS: Six to eight weeks old male type 2 diabetes and age matched control inbred mice were used and maxillary molar tooth extractions were performed. At 4 and 7 days after tooth extraction, the edentulous mucosa of the mice were harvested, and analyzed for histology and gene expression of key wound healing factors. RESULTS: In the diabetic model, histological analysis showed that epithelial tissue migration for wound closure was delayed after tooth extraction compared to the control. Quantitative real-time PCR revealed that expression of the TGF-β1, TGF-β2, TGF-β3, TGFβRII and TGFβRIII genes was significantly downregulated in the diabetic model at 4 and 7 days after tooth extraction. CONCLUSION: These results suggest that delayed wound healing of oral mucosa in diabetes may be associated with decreased expression levels of these regulatory genes which play important roles in controlling epithelial wound closure.
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In order to determine whether a newly developed implant material conforms to the requirements of biocompatibility, it must undergo rigorous testing. To correctly interpret the results of studies on implant material osseointegration, it is necessary to have a sound understanding of all the testing methods. The aim of this overview is to elucidate the methods that are used for the experimental evaluation of the osseointegration of implant materials.
In recent decades, there has been a constant proliferation of new materials and surface modifications in the field of dental implants. This continuous development of innovative biomaterials requires a precise and detailed evaluation in terms of biocompatibility and implant healing before clinical use. The current gold standard is in vivo animal testing on well validated animal models. However, long-term outcome studies on patients have to follow to finally validate and show patient benefit.
No experimental set-up can provide answers for all possible research questions. However, a certain transferability of the results to humans might be possible if the experimental set-up is carefully chosen for the aspects and questions being investigated. To enhance the implant survival rate in the rising number of patients with chronic diseases which compromise wound healing and osseointegration, dental implant research on compromised animal models will further gain importance in future.
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