0000000000480515
AUTHOR
Jonas Lorenz
Platelet rich fibrin-a promising approach for tissue regeneration in oral and maxillofacial surgery: preclinical and clinical studies
High-Temperature Sintering of Xenogeneic Bone Substitutes Leads to Increased Multinucleated Giant Cell Formation: In Vivo and Preliminary Clinical Results.
The present preclinical and clinical study assessed the inflammatory response to a high-temperature–treated xenogeneic material (Bego-Oss) and the effects of this material on the occurrence of multinucleated giant cells, implantation bed vascularization, and regenerative potential. After evaluation of the material characteristics via scanning electron microscopy, subcutaneous implantation in CD-1 mice was used to assess the inflammatory response to the material for up to 60 days. The clinical aspects of this study involved the use of human bone specimens 6 months after sinus augmentation. Established histologic and histomorphometric analysis methods were applied. After implantation, the mat…
TRAP-Positive Multinucleated Giant Cells Are Foreign Body Giant Cells Rather Than Osteoclasts: Results From a Split-Mouth Study in Humans
This study compared the material-specific tissue response to the synthetic, hydroxyapatite-based bone substitute material NanoBone (NB) with that of the xenogeneic, bovine-based bone substitute material Bio-Oss (BO). The sinus cavities of 14 human patients were augmented with NB and BO in a split-mouth design. Six months after augmentation, bone biopsies were extracted for histological and histomorphometric investigation prior to dental implant insertion. The following were evaluated: the cellular inflammatory pattern, the induction of multinucleated giant cells, vascularization, the relative amounts of newly formed bone, connective tissue, and the remaining bone substitute material. NB gra…
Porcine Dermis-Derived Collagen Membranes Induce Implantation Bed Vascularization Via Multinucleated Giant Cells: A Physiological Reaction?
In this study, the tissue reactions to 2 new porcine dermis-derived collagen membranes of different thickness were analyzed. The thicker material (Mucoderm) contained sporadically preexisting vessel skeletons and fatty islands. The thinner membrane (Collprotect) had a bilayered structure (porous and occlusive side) without any preexisting structures. These materials were implanted subcutaneously in mice to analyze the tissue reactions and potential transmembranous vascularization. Histological and histomorphometrical methodologies were performed at 4 time points (3, 10, 15, and 30 days). Both materials permitted stepwise connective tissue ingrowth into their central regions. In the Mucoderm…
Application of a three-dimensional collagen matrix for covering of cutaneous resection defects-preclinical and preliminary results from the first application in humans
Collagen membranes induce different vascularization and cellular inflammatory response in relation to their origin – in vivo and clinical studies
Porcine Dermis and Pericardium-Based, Non–Cross-Linked Materials Induce Multinucleated Giant Cells After Their In Vivo Implantation: A Physiological Reaction?
The present study analyzed the tissue reaction to 2 novel porcine-derived collagen materials: pericardium versus dermis. By means of the subcutaneous implantation model in mice, the tissue reactions were investigated at 5 time points: 3, 10, 15, 30, and 60 days after implantation. Histologic, histochemical, immunhistologic, and histomorphometric analysis methodologies were applied. The dermis-derived material underwent an early degradation while inducing mononuclear cells together with some multinucleated giant cells and mild vascularization. The pericardium-derived membrane induced 2 different cellular tissue reactions. The compact surface induced mononuclear cells and multinucleated giant…
Nanocrystalline Hydroxyapatite-Based Material Already Contributes to Implant Stability After 3 Months: A Clinical and Radiologic 3-Year Follow-up Investigation
The present study reports on a 3-year clinical and radiologic follow-up investigation of dental implants placed 3 and 6 months after sinus augmentation in 14 patients. Augmentation was performed with a synthetic bone substitute material composed of nanocrystalline hydroxyapatite. The aim of the study was to determine how the integration period of the bone substitute material, that is, 3 months or 6 months, influences implant integration within the patient's upper jaw. Therefore, the following clinical and radiologic parameters were investigated: implant being in situ; Periotest value; and presence of peri-implant osteolysis, bleeding on probing, plaque, and soft tissue recession around the …
Foreign Body Giant Cell–Related Encapsulation of a Synthetic Material Three Years After Augmentation
Bone substitute materials of different origin and chemical compositions are frequently used in augmentation procedures to enlarge the local bone amount. However, relatively little data exist on the long-term tissue reactions. The presented case reports for the first time histological and histomorphometrical analyses of a nanocrystaline hydroxyapatite–based bone substitute material implanted in the human sinus cavity after an integration period of 3 years. The extracted biopsy was analyzed histologically and histomorphometrically with focus on the tissue reactions, vascularization, new bone formation, and the induction of a foreign body reaction. A comparably high rate of connective tissue (…
Potential lack of "standardized" processing techniques for production of allogeneic and xenogeneic bone blocks for application in humans.
In the present study, the structure of two allogeneic and three xenogeneic bone blocks, which are used in dental and orthopedic surgery, were histologically analyzed. The ultimate goal was to assess whether the components postulated by the manufacturer can be identified after applying conventional histological and histochemical staining techniques. Three samples of each material, i.e. allogeneic material-1 and -2 as well as xenogeneic material-1, -2 and -3, were obtained commercially. After decalcification and standardized embedding processes, conventional histological staining was performed in order to detect inorganic matrix, cellular or organic matrix components. Allogeneic material-1 sh…
Advanced Platelet-Rich Fibrin: A New Concept for Cell-Based Tissue Engineering by Means of Inflammatory Cells
Choukroun's platelet-rich fibrin (PRF) is obtained from blood without adding anticoagulants. In this study, protocols for standard platelet-rich fibrin (S-PRF) (2700 rpm, 12 minutes) and advanced platelet-rich fibrin (A-PRF) (1500 rpm, 14 minutes) were compared to establish by histological cell detection and histomorphometrical measurement of cell distribution the effects of the centrifugal force (speed and time) on the distribution of cells relevant for wound healing and tissue regeneration. Immunohistochemistry for monocytes, T and B -lymphocytes, neutrophilic granulocytes, CD34-positive stem cells, and platelets was performed on clots produced from four different human donors. Platelets …