[Drug-coated balloons in the treatment of peripheral artery disease (PAD). History and current level of evidence]. / Medikamentenbeschichtete Ballonkatheter in der PAVK­Behandlung. Entwicklung der Methode und aktuelle Studienlage.

BACKGROUND: Despite initially encouraging technical success after femoropopliteal PTA, restenosis remains the major challenge in patients with peripheral artery disease (PAD). The main cause of restenosis is neointimal hyperplasia which can be suppressed by antiproliferative drugs. Drug-coated balloons (DCB) or drug-eluting stents (DES) are used for the inhibition of restenosis. OBJECTIVES: The present article gives an overview of DCB development, actual DCB systems for femoro- and infrapopliteal use, displays the outcomes of randomized clinical trials and the discusses the evidence for the DCB treatment in PAD. METHODS: A systematic literature search was performed in i) medical journals (i. e. MEDLINE), ii) in international registers for clinical studies (i. e. www.clinicaltrials.gov ) and in iii) scientific session abstracts. RESULTS: The clinical evidence of the PTX-DCB of the first and following generation has been shown in several controlled randomized trials. CONCLUSIONS: Major advantages of the DCBs lie in leaving no stent scaffold behind, the immediate release of high drug concentrations with a single dosage, their efficacy in areas, where stents have been contra-indicated until now and its use for secondary interventions. As their effect seems to be limited in severely calcified lesions, prior plaque preconditioning or removal could be advantageous. First positive results data supporting this hypothesis do exist.

Hyperbaric oxygen therapy improves angiogenesis and bone formation in critical sized diaphyseal defects.

Besides the use of autologous bone grafting several osteoconductive and osteoinductive methods have been reported to improve bone healing. However, persistent non-union occurs in a considerable number of cases and compromised angiogenesis is suspected to impede bone regeneration. Hyperbaric oxygen therapy (HBO) improves angiogenesis. This study evaluates the effects of HBO on bone defects treated with autologous bone grafting in a bone defect model in rabbits. Twenty-four New-Zealand White Rabbits were subjected to a unilateral critical sized diaphyseal radius bone defect and treated with autologous cancellous bone transplantation. The study groups were exposed to an additional HBO treatment regimen. Bone regeneration was evaluated radiologically and histologically at 3 and 6 weeks, angiogenesis was assessed by immunohistochemistry at three and six weeks. The additional administration of HBO resulted in a significantly increased new bone formation and angiogenesis compared to the sole treatment with autologous bone grafting. These results were apparent after three and six weeks of treatment. The addition of HBO therapy to autologous bone grafts leads to significantly improved bone regeneration. The increase in angiogenesis observed could play a crucial role for the results observed.

The effect of bone marrow concentrate and hyperbaric oxygen therapy on bone repair.

Neoangiogenesis represents an essential part of bone regeneration. Therefore the improvement of neovascularization is the subject of various research approaches. In addition autologous mesenchymal stem cells concentrate in combination with bone substitute materials have been shown to support bone regeneration. In a rabbit model we examined the proposed synergistic effect of hyperbaric oxygen therapy (HBOT) and bone marrow concentrate (BMC) with porous calcium phosphate granules (CPG) on neoangiogenesis and osseous consolidation of a critical- size defect. The animal groups treated with HBOT showed a significantly higher microvessel density (MVD) by immunhistochemistry. Furthermore HBOT groups presented a significantly larger amount of new bone formation histomorphometrically as well as radiologically. We conclude that the increase in perfusion as a result of increased angiogenesis may play a key role in the effects of HBOT and consequently promotes bone healing.

Long-term outcome of femoropopliteal stenting. Results of a prospective study.

AIM: Aim of the study was to assess the long-term clinical results of primary stent placement in patients with femoro-popliteal lesions and intermittent claudication (IC) or critical limb ischemia (CLI). METHODS: Prospectively collected data of 517 patients (543 limbs) treated for IC (N.=422; 77.5%) and CLI (N.=121; 22.5%), between September 2006 and December 2010 were evaluated. Survival, limb salvage and patency rates were analyzed and multivariate analysis was performed to evaluate possible risk factors for the development of restenosis. RESULTS: Mean patients' age was 70.6 years (SD ±10); 64.8% of the patients (N.=335) were male. Angiography revealed TASC A or B lesions in 64.5% (N.=350), TASC C or D lesions in 35.5% (N.=193) of the patients. Two hundred thirty-two patients had evidence of occluded femoropopliteal artery (42.7%) and the remaining patients had evidence of high grade (>70%) stenosis. In total, 827 bare metal nitinol stents (1.53±0.9 per limb) were used. No early (<30-day) procedure-related death was recorded. After a mean follow-up period of 60 months (SD ±13.5), 69 patients died (13.4%). Eight (1.5%) patients underwent major amputation. The amputation rate was significantly higher in the CLI group compared to the IC group (P=0.03). Primary patency rates were 86.2%, 79.1%, 75.1% and 62.2% after 1, 2, 3 and 5 years, respectively. No difference in terms of patency rates was found between the results of the treatment of TASC A/B versus TASC C/D lesions and the patient groups with IC versus CLI. CONCLUSION: The endovascular-first line treatment with use of nitinol stents for patients with femoropopliteal artery lesions is associated with acceptable long-term patency rates, even in patients with long lesions.

The distribution of nociceptive innervation in the painful hip: a histological investigation.

Our understanding of the origin of hip pain in degenerative disorders of the hip, including primary osteoarthritis, avascular necrosis and femoroacetabular impingement (FAI), is limited. We undertook a histological investigation of the nociceptive innervation of the acetabular labrum, ligamentum teres and capsule of the hip, in order to prove pain- and proprioceptive-associated marker expression. These structures were isolated from 57 patients who had undergone elective hip surgery (44 labral samples, 33 ligamentum teres specimens, 34 capsular samples; in 19 patients all three structures were harvested). A total of 15,000 histological sections were prepared that were investigated immunohistochemically for the presence of protein S-100, 68 kDa neurofilament, neuropeptide Y, nociceptin and substance P. The tissues were evaluated in six representative areas. Within the labrum, pain-associated free nerve ending expression was located predominantly at its base, decreasing in the periphery. In contrast, the distribution within the ligamentum teres showed a high local concentration in the centre. The hip capsule had an almost homogeneous marker expression in all investigated areas. This study showed characteristic distribution profiles of nociceptive and pain-related nerve fibres, which may help in understanding the origin of hip pain.

The early phase influence of bone marrow concentrate on metaphyseal bone healing.

Bone marrow concentrate (BMC) contains high densities of progenitor cells. Therefore, in critical size defects BMC may have the potency to support bone healing. The aim of this study was to investigate the effect of BMC in combination with calcium phosphate granules (CPG) on bone defect healing in a metaphyseal long bone defect in mini-pigs. A metaphyseal critical-size bone defect at the proximal tibia of 24 mini-pigs was filled with CPG combined with BMC, CPG solely (control group) or with an autograft. Radiological and histomorphometrical evaluations after 6 weeks (42 days) showed significantly more bone formation in the BMC group in the central area of the defect zone and the cortical defect zone compared to the CPG group. At the same time the resorption rate of CPG increased significantly in the BMC group. Nevertheless, compared to the BMC group the autograft group showed a significantly higher new bone formation radiologically and histomorphometrically. In BMC the count of mononuclear cells was significantly higher compared to the bone marrow aspirate (3.5-fold). The mesenchymal progenitor cell characteristics of the cells in BMC were confirmed by flow cytometry. Cells from BMC created significantly larger colonies of alkaline phosphatase-positive colony forming units (CFU-ALP) (4.4-fold) compared to cells from bone marrow aspirate. Nevertheless, even in the BMC group complete osseous bridging was only detectable in isolated instances of the bone defects. Within the limitations of this study the BMC+CPG composite promotes bone regeneration in the early phase of bone healing significantly better than the isolated application of CPG. However, the addition of BMC does not lead to a solid fusion of the defect in the early phase of bone healing an still does not represent an equal alternative to autologous bone.

Osteoblastic potency of bone marrow cells cultivated on functionalized biometals with cyclic RGD-peptide.

The fixation of cementless endoprostheses requires excellent fixation at the bone implant interface. Although the surface structures of these implants are designed to promote osteoblastic differentiation, poor bone quality may prevent or delay osseointegration. There is evidence that RGD peptides known as recognition motifs for various integrins, promote cellular adhesion, influence cellular proliferation, and differentiation of local cells. In this study, five different metal surfaces were analyzed: Sandblasted (TiSa) and polished (TiPol) Ti6Al4V, porocoated (CCPor) and polished (CCPol) cobalt chrome and polished stainless steel (SS) were coated by ethanol amine and poly(ethylene glycol) to attach covalently RGD peptides. Human mesenchymal stromal cells of healthy donors were cultivated onto prior functionalized metal surfaces for 14 days without osteogenic stimulation. Cell proliferation and differentiation were quantitatively evaluated for native (I), NaOH pre-activated (II), NaOH pre-activated, and PEG-coated (III) as well as for RGD (IV) coated surfaces. The RGD immobilization efficiency was analyzed by epi-fluorescence spectroscopy, cell morphology was documented by light and scanning electron microscopy. The RGD-binding efficiency was TiSa > TiPol > SS > CCPor > CCPol. RGD coated surfaces showed the highest average cell proliferation on CCPol > SS > CCPor > TiSa ≥ TiPol, whereas cellular differentiation mostly correlated with the observed proliferation results, such as CCPol > TiSa > SS > CCPor > TiPol. Considering statistical analyses (significance level of α = 0.05), the RGD-coating of all biometals in comparison and in respect of their particular controls showed no significant improvement in cellular proliferation and osteoblastic differentiation.

Histological variations of the glenoid labrum in dogs.

As the structure and clinical meaning of the canine glenoid labrum are repeatedly disputed up to now, an anatomical histological description of the structure and its varieties in older dogs is carried out. In this study, 20 shoulder joints are histologically and immunohistologically examined. The glenoid labrum (GL) is composed of up to three different zones: a transition zone composed of fibre cartilage with collagen fibres arranged like a fishnet-like pattern, a zone of circularly leading fibre bundles and a meniscoid fold with synovial coverage. A variable recess exists between the GL and the joint surface.

Bone marrow concentrate for autologous transplantation in minipigs. Characterization and osteogenic potential of mesenchymal stem cells.

Autologous bone marrow plays an increasing role in the treatment of bone, cartilage and tendon healing disorders. Cell-based therapies display promising results in the support of local regeneration, especially therapies using intra-operative one-step treatments with autologous progenitor cells. In the present study, bone marrow-derived cells were concentrated in a point-of-care device and investigated for their mesenchymal stem cell (MSC) characteristics and their osteogenic potential. Bone marrow was harvested from the iliac crest of 16 minipigs. The mononucleated cells (MNC) were concentrated by gradient density centrifugation, cultivated, characterized by flow cytometry and stimulated into osteoblasts, adipocytes, and chondrocytes. Cell differentiation was investigated by histological and immunohistological staining of relevant lineage markers. The proliferation capacity was determined via colony forming units of fibroblast and of osteogenic alkaline-phosphatase-positive-cells. The MNC could be enriched 3.5-fold in nucleated cell concentrate in comparison to bone marrow. Flow cytometry analysis revealed a positive signal for the MSC markers. Cells could be differentiated into the three lines confirming the MSC character. The cellular osteogenic potential correlated significantly with the percentage of newly formed bone in vivo in a porcine metaphyseal long-bone defect model. This study demonstrates that bone marrow concentrate from minipigs display cells with MSC character and their osteogenic differentiation potential can be used for osseous defect repair in autologous transplantations.

T2* mapping of hip joint cartilage in various histological grades of degeneration.

OBJECTIVE: To evaluate T2* values in various histological severities of osteoarthritis (OA). METHOD: Magnetic resonance imaging (MRI) and T2* mapping including a three-dimensional (3D) double-echo steady-state (DESS) sequence for morphological cartilage assessment and a 3D multiecho data image combination (MEDIC) sequence for T2* mapping were conducted in 21 human femoral head specimens with varying severities of OA. Subsequently, histological assessment was undertaken in all specimens to correlate the observations of T2* mapping with histological analyses. According to the Mankin score, four grades of histological changes were determined: grade 0 (Mankin scores of 0-4), grade I (scores of 5-8), grade II (scores of 9-10), and grade III (scores of 11-14). For reliability assessment, cartilage T2* measurements were repeated after 4 weeks in 10 randomly selected femoral head specimens. RESULTS: T2* values decreased significantly with increasing cartilage degeneration (total P-values <0.001) ranging from 36.3 ± 4.3 ms in grade 0 regions to 22.8 ± 4.3 ms in regions with grade III changes. Pearson correlation analysis proved a fair correlation between T2* values and Mankin score (correlation coefficient = -0.362) that was statistically significant (P-value <0.001). Intra-class correlation (ICC) analysis demonstrated high intra-observer reproducibility for the T2* measurement (ICC: 0.949, P < 0.001). CONCLUSIONS: Given the advantages of the T2* mapping technique with no need for contrast medium, high image resolution and ability to perform 3D biochemically sensitive imaging, T2* mapping may be a strong addition to the currently evolving era of cartilage biochemical imaging.

[Regeneration of osteochondral defects in the knee]. / Zelltherapie zur Knorpelregeneration im Kniegelenk.

The application of autologous cells is a standard procedure for the treatment of chondral lesions of the knee. Here, the most frequently used cells are differentiated chondrocytes (autologous chondrocyte implantation, ACI; matrix-induced autologous chondrocyte implantation, MACI). The enzymatic digestion of cartilage tissue by collagenase and isolation of chondrocytes followed by in vitro cultivation are associated with cellular de- and transdifferentiation. To prevent these effects some authors recommend 3D-cultures and culture medium supplementation of defined growth factors and cytokines. Another aim is the reduction of donor site morbidity. Therefore, different progenitor cell types were tested towards their potential for osteochondral regeneration. In particular, MSC derived from bone marrow include several advantages for the treatment of osteochondral defects such as unproblematic sampling, cultivation techniques, and a relatively high degree of biological safety. This review summarises the basic cellular principles as well as clinical results of cell therapeutics for the regeneration of osteochondral defects in the knee.

[Cell therapy in bone-healing disorders]. / Zelltherapie bei Knochenheilungsstörungen.

In addition to stabilizing osteosynthesis and autologous bone transplantation, so-called orthobiologics are playing an increasing role in the treatment of bone-healing disorders. Besides the application of different growth factors, new data in the literature suggest that cell therapeutic agents promote local bone regeneration. Due to ethical and biological considerations, clinical application of progenitor cells for the musculoskeletal system is limited to autologous postpartum stem cells. Here in particular, cell therapy with autologous progenitor cells in one surgical session has delivered first promising results. Based on a review of the literature and on our own experience with 75 patients, this article reviews the rationale and characteristics of the clinical application of cell therapy for the treatment of bony substance defects. Most clinical trials report successful bone regeneration after the application of mixed cell populations from bone marrow.

Combined use of platelet-rich plasma and autologous bone grafts in the treatment of long bone defects in mini-pigs.

The use of platelet-rich plasma (PRP) for improving of bone defect healing is discussed controversially. The aim of this study was to assess the effect of PRP in combination with autologous cancellous graft on bone defect healing in a critical metaphyseal long bone defect. A critical size defect in the tibial metaphysis of 16 mini-pigs was filled either with autologous cancellous graft as control group or with autologous cancellous graft combined with autologous PRP. Compared to native blood platelets were enriched about 4.9-fold in the PRP. After 6 weeks, the specimens were assessed by X-ray and histological evaluation. Histomorphometrical analysis revealed that the area of new bone was significantly higher in the PRP group concerning the central area of the defect zone (p<0.02) as well as the cortical defect zone (p<0.01). All defects showed substantial new bone formation, but only defects of the PRP group regenerated entirely. The PRP group was superior to the control group even in the semi-quantitative assessment of the osseous bridging in both observed areas of the defect. Within the limits of the present study it could be demonstrated that PRP combined with autologous cancellous graft leads to a significantly better bone regeneration compared to isolated application of autologous cancellous graft in an in vivo critical size defect on load-bearing long bones of mini-pigs.

Surface- and nonsurface-dependent in vitro effects of bone substitutes on cell viability.

The aim of the present in vitro study was to evaluate the influence of different bone substitute materials (BSM) on the viability of human primary osteoblasts (PO), bone marrow mesenchymal cells (BMMC), and nonadherent myelomonocytic cells (U937). Six different bone substitute materials were tested: Bio-Oss Spongiosa (BOS), Tutodent Chips (TC), PepGen P-15 (P-15), Ostim (OM), BioBase (BB), and Cerasorb (CER). Cells were cultivated on comparable volumes of BSM in 96-well plates. Cell culture-treated polystyrol (Nunclon Delta surface; C) served as positive control. After 2 h and 3, 6, 10, and 14 days, viability of cells was evaluated using a standardized ATP viability assay (CellTiter Glo). Nonsurface-dependent effects of the materials were separately tested using nonadherent U937 suspension cells. For statistical analysis, the Mann-Whitney test was used. Results were considered statistically significant at P < 0.05. Cell viability of PO increased significantly on TC, C, and CER followed by BB. No changes were found for P-15 and decreasing viability for BOS and OM. BMMC showed similar results on C, TC, CER, and P-15. Lower viability for BB and no viability could be detected for BOS and OM (Mann-Whitney test, respectively). Nonadherent cells displayed increasing viability in presence of CER, BB, and BOS. No changes were observed for TC and P-15, whereas for OM, no viability was detected after a maximum cultivation period of 3 days. It was concluded that granular hydroxyapatite (HA; TC, BOS, P-15) and alpha- and beta-tricalciumphosphate (CER, BB) support, whereas nanosized HA (OM) limit or even inhibit surface- and nonsurface-related cell viability in the in vitro model used.

A genome screen of 35 bipolar affective disorder pedigrees provides significant evidence for a susceptibility locus on chromosome 15q25-26.

Bipolar affective disorder is a heritable, relatively common, severe mood disorder with lifetime prevalence up to 4%. We report the results of a genome-wide linkage analysis conducted on a cohort of 35 Australian bipolar disorder families which identified evidence of significant linkage on chromosome 15q25-26 and suggestive evidence of linkage on chromosomes 4q, 6q and 13q. Subsequent fine-mapping of the chromosome 15q markers, using allele frequencies calculated from our cohort, gave significant results with a maximum two-point LOD score of 3.38 and multipoint LOD score of 4.58 for marker D15S130. Haplotype analysis based on pedigree-specific, identical-by-descent allele sharing, supported the location of a bipolar susceptibility gene within the Z(max-1) linkage confidence interval of 17 cM, or 6.2 Mb, between markers D15S979 and D15S816. Non-parametric and affecteds-only linkage analysis further verified the linkage signal in this region. A maximum NPL score of 3.38 (P=0.0008) obtained at 107.16 cM (near D15S130), and a maximum two-point LOD score of 2.97 obtained at marker D15S1004 (affecteds only), support the original genome-wide findings on chromosome 15q. These results are consistent with four independent positive linkage studies of mood and psychotic disorders, and raise the possibility that a common gene for susceptibility to bipolar disorder, and other psychiatric disorders may lie in this chromosome 15q25-26 region.

Dimensional ridge alterations following socket preservation using a nanocrystalline hydroxyapatite paste: a histomorphometrical study in dogs.

The aim of the study was to evaluate the histological response and dimensional ridge alterations following application of a nanocrystalline hydroxyapatite paste (NHA) into fresh extraction sockets in dogs. Immediately following vertical tooth separation and extraction, NHA was inserted in the extraction socket of the second molar in the lower jaws of 10 dogs. Untreated extraction sites on the opposite side served as controls. Wounds were closed using resorbable sutures after vertical flap elevation. After three and six months, 5 animals were killed. Lingual and buccal bone height, alveolar wall and total bone width 1, 3 and 5mm underneath the top of the crest were evaluated. Histological analysis revealed a high variability of NHA resorption and osteoconductive properties with different rates of material resorption. No statistically significant differences could be observed between the corresponding aspects of test and control sites. Both groups revealed higher alveolar wall resorption on the buccal than on the lingual side at both time periods. NHA does not seem to be useful for socket preservation procedures since it failed to prevent dimensional ridge alterations while revealing osseous integration but unpredictable material resorption. The role of non-resorbed hydroxyapatite remnants for implant placement is unclear and requires further investigation.

Guided bone regeneration at dehiscence-type defects using biphasic hydroxyapatite + beta tricalcium phosphate (Bone Ceramic) or a collagen-coated natural bone mineral (BioOss Collagen): an immunohistochemical study in dogs.

The aim of this study was to immunohistochemically investigate bone regeneration following application of either hydroxyapatite+beta tricalcium phosphate (BCG) or a collagen-coated natural bone mineral (BOC) in combination with a collagen membrane at dehiscence-type defects in dogs. Standardized buccal dehiscence defects were surgically created following implant bed preparation in six beagle dogs. Defects were randomly filled with either BOC (BioOss Collagen) or BCG (Bone Ceramic) according to a split-mouth design, and covered with a native porcine derived collagen membrane (BioGide). After 1, 4 and 9 weeks of submerged healing, dissected blocks were processed for immunohistochemical (osteocalcin) and histomorphometrical analysis (residual defect length, new bone-implant contact, area of new bone fill, percentage of osseointegrated bone-graft particles). Both groups revealed a significant decrease in mean residual defect length, and increases in mean new bone-implant contact, bone fill and percentage of osseointegrated bone-graft particles after 4 and 9 weeks of healing. Remaining BCG and BOC granules were completely integrated into a secondarily formed network of spongiosa, but there was no osteoclastic activity at the surface of either type of bone-graft particle. Both BCG and BOC may provide an osteoconductive scaffold to support guided bone regeneration procedures at dehiscence-type defects.

Influence of implant bed preparation using an Er:YAG laser on the osseointegration of titanium implants: a histomorphometrical study in dogs.

The aim of the present study was to evaluate the influence of implant bed preparation using an Er:YAG laser on the osseointegration of titanium implants. A total of 24 implant channels were prepared in the lower jaws of four beagle dogs using (i) an Er:YAG laser device (ERL), or (ii) conventional drills (CD) according to a split-mouth design (n=6 implant channels per animal). Three screw-type titanium implants of different manufacturers were randomly inserted in both groups to evaluate submerged healing at 2 and 12 weeks. Width of the peri-implant gap (WPG) and bone-to-implant contact (BIC) were assessed histomorphometrically. There were no identifiable signs of any thermal side effects in both groups. ERL osteotomy frequently resulted in wide peri-implant gaps particularly in the apical area of the implant supporting bone. The following mean scores were assessed (+/-s.d.): WPG (2 weeks): ERL: 0.89+/-0.48 mm; CD: 0.27+/-0.09 mm (P<0.001 respectively); BIC (2 weeks): ERL: 34.5+/-7.76%; CD: 48.5+/-11.08% (P<0.001 respectively); BIC (12 weeks): ERL: 64.1+/-8.97%; CD: 68.94+/-11.23% (P>0.05 respectively). Within the limits of the present study, it was concluded that ERL may represent a promising tool for implant bed preparation.

[In vitro testing of thrombocyte adhesion to different collagenous hemostyptic agents]. / In-vitro-Testung der Thrombozytenaggregation an zahnärztlich verwendeten kollagenen Hämostyptika.

AIM: The aim of the present study was to evaluate the adhesion of thrombocytes to different collagenous hemostyptics in a new blood flow chamber. MATERIAL AND METHODS: Three hemostyptics were tested: (1) Resorba (RE, native equine collagen, Resorba Wundversorgung GmbH, Nürnberg, Germany), (2) Hemocol (HE, native porcine collagen, Medical Biomaterial Products GmbH, Neustadt-Gleve, Germany), and (3) an experimental sponge (ES, chemically cross-linked porcine collagen, Geistlich Biomaterials, Wolhusen, Switzerland). Ten specimens of each sponge were exposed to a laminar 40 ml/h anticoagulated blood flow and adhering thrombocytes were examined using a confocal laser scanning microscope (CLSM). Pure collagen (Kollagen S, Roche) served as positive control and fetal calf serum (FKS, Roche) as negative control. Examination time was set at 0, 60, 120, and 180 s. Furthermore, pH measurements of defined sponge volumes were evaluated after incubation with NaCl and human blood serum after 3, 30, and 60 min. RESULTS: All specimens showed a comparable amount of fluorescence units on the surface over time which was statistically not significantly different from the positive control (p>0.05, ANOVA). Nevertheless, acidity of all specimens could be observed after incubation with NaCl and in cases of HE and ES after incubation with human blood serum. CONCLUSION: Within the limits of the present in-vitro study it was concluded that (1) all hemostyptics examined showed similar results in thrombocyte adhesion; (2) chemical cross-linking of collagen does not affect the thrombogenicity of the tested collagen; (3) however, the acidity might have a negative effect on thrombus formation in vivo.

Autogenous bone chips: influence of a new piezoelectric device (Piezosurgery) on chip morphology, cell viability and differentiation.

AIM: The aim of the present study was to investigate the influence of a new piezoelectric device, designed for harvesting autogenous bone chips from intra-oral sites, on chip morphology, cell viability and differentiation. METHODS: A total of 69 samples of cortical bone chips were randomly gained by either (1) a piezoelectric device (PS), or (2) conventional rotating drills (RD). Shape and size of the bone chips were compared by means of morphometrical analysis. Outgrowing osteoblasts were identified by means of alkaline phosphatase activity (AP), immunhistochemical staining for osteocalcin (OC) synthesis and reverse transcriptase-polymerase chain reaction phenotyping. RESULTS: In 88.9% of the RD and 87.9% of the PS specimens, an outgrowth of adherent cells nearby the bone chips was observed after 6-19 days. Confluence of cells was reached after 4 weeks. Positive staining for AP and OC identified the cells as osteoblasts. The morphometrical analysis revealed a statistically significant more voluminous size of the particles collected with PS than RD. CONCLUSION: Within the limits of the present study, it may be concluded that both the harvesting methods are not different from each other concerning their detrimental effect on viability and differentiation of cells growing out of autogenous bone chips derived from intra-oral cortical sites.