Search results for "Calvaria"

2018

The bioactive coating of calcium phosphate cement (CPC) is a promising approach to enhance the bone-healing properties of bone substitutes. The purpose of this study was to evaluate whether coating CPCs with bone sialoprotein (BSP) results in increased bone formation. Forty-five female C57BL/6NRj mice with an average age of six weeks were divided into three groups. Either a BSP-coated or an uncoated three-dimensional plotted scaffold was implanted into a drilled 2.7-mm diameter calvarial defect, or the defect was left empty (control group; no CPC). Histological analyses revealed that BSP-coated scaffolds were better integrated into the local bone stock eight weeks after implantation. Bone v…

CD34+cells seeded in collagen scaffolds promote bone formation in a mouse calvarial defect model

2017

Bone tissue engineering (BTE) holds promise for managing the clinical problem of large bone defects. However, clinical adoption of BTE is limited due to limited vascularization of constructs, which could be circumvented by pre-cultivation of osteogenic and endothelial derived cells in natural-based polymer scaffolds. However, until now not many studies compared the effect of mono- and cocultures pre-seeded in collagen before implantation. We utilized a mouse calvarial defect model and compared five groups of collagen scaffolds: a negative control of a collagen scaffold alone, a positive control treated with BMP-7, monocultures of either human osteoblasts (hOBs) or CD34+ cells, and a cocultu…

Polyphosphate as a Bioactive and Biodegradable Implant Material: Induction of Bone Regeneration in Rats

2016

Inorganic polyphosphate (polyP) is a naturally occurring polymer that is bioresorbable and anabolically active on bone forming cells in vitro. In order to demonstrate if polyP also shows morphogenetic activity in vivo, animal studies are performed applying the rat calvarial defect model. Poly(D,L-lactide-co-glycolide) (PLGA) microspheres with a narrow size distribution (≈820 μm) are prepared, containing either encapsulated polyP or β-tricalcium phosphate (β-TCP), used as a reference material. Discs are prepared from the microspheres and inserted into 10 mm large defects created in the calvaria of rats. Both the formation of COL-I and the expression of ALP is upregulated, as well as the exte…

Comparison of implant primary stability between maxillary edentulous ridges receiving intramembranous origin block grafts

2012

Purpose: The purposes of the present study were: to compare the resonance frequency analysis (RFA) values of implant placed in either ramus or calvaria block grafts; and to determine if implant diameter influences RFA implant stability quotient (ISQ) value. Material and Methods: This was a retrospective study that included 16 consecutives healthy patients treated with autogenous onlay block grafts for horizontal bone reconstruction in maxilla. Ten ramus and ten calvaria block graft treated patients were selected and compared. Results: Totally, 59 implants were placed, 35 (59.3%) were placed on the calvaria bone grafts and the remaining 24 (40.7%) were on the ramus bone graft. Of all the imp…

The Serum Protein α2-HS Glycoprotein/Fetuin Inhibits Apatite Formation in Vitro and in Mineralizing Calvaria Cells

1996

We present data suggesting a function of alpha2-HS glycoproteins/fetuins in serum and in mineralization, namely interference with calcium salt precipitation. Fetuins occur in high serum concentration during fetal life. They accumulate in bones and teeth as a major fraction of noncollagenous bone proteins. The expression pattern in fetal mice confirms that fetuin is predominantly made in the liver and is accumulated in the mineralized matrix of bones. We arrived at a hypothesis on the molecular basis of fetuin function in bones using primary rat calvaria osteoblast cultures and salt precipitation assays. Our results indicate that fetuins inhibit apatite formation both in cell culture and in …

Fragmented adipose tissue graft for bone healing: histological and histometric study in rabbits' calvaria

2012

Objective The adipose tissue represents an important reservoir of stem cells. There are few studies in the literature with which to histologically evaluate whether or not the adipose tissue graft is really a safe option to achieve bone repair. This study histologically analyzed the effect of fragmented autogenous adipose tissue grafts on bone healing in surgically created, critical-size defects (CSD) in a rabbit’s calvaria. Study design Forty-two New Zealand rabbits were used in this study. CSD that were 15 mm in diameter were created in the calvarium of each animal. The defects were randomly divided into two groups: in Group C (control), the defect was filled only by a blood clot and, in G…

Intermittent administration of parathyroid hormone improves the repairing process of rat calvaria defects: A histomorphometric and radiodensitometric…

2014

Background: The aim of this study was to evaluate the effects of intermittent treatment of parathyroid hormone (PTH (1-34)) on the bone regeneration of critically-sized rat calvarial bone defects. Material and Methods: Thirty-two male rats were trephined (4mm fullthickness diameter), in the central part of the parietal bones and divided into 2 groups of 16. The PTH group received subcutaneous injections of PTH (1-34) at 40μg/kg, 3 times a week and the control (CTL) group received the vehicle in the same regimen. The rats were sacrificed at 4 weeks post-treatment regimen, the parietal bones were extracted and samples were evaluated through histomorphometry and radiodensitometry. Results: The…

Melatonin enhances vertical bone augmentation in rat calvaria secluded spaces.

2015

Background Melatonin has many roles, including bone remodeling and osseointegration of dental implants. The topical application of melatonin facilitated bone regeneration in bone defects. We evaluated the effects of topical application of melatonin on vertical bone augmentation in rat calvaria secluded spaces. Material and Methods In total, 12 male Fischer rats were used and two plastic caps were fixed in the calvarium. One plastic cap was filled with melatonin powder and the other was left empty. Results Newly generated bone at bone defects and within the plastic caps was evaluated using micro-CT and histological sections. New bone regeneration within the plastic cap was increased signific…

The Influence of PRP on Early Bone Formation in Membrane Protected Defects. A Histological and Histomorphometric Study in the Rabbit Calvaria

2011

Background: Platelet rich plasma (PRP) has been proposed to be a useful adjunct to bone grafting. Purpose: The aim of the present study was to assess new bone formation in bone regeneration procedures using platelet rich plasma (PRP) alone or in combination with autogenous bone. Materials and Methods: Four surgically created, monocortical defects 5 mm in diameter in the calvariae of 15 New Zealand rabbits were grafted with a coagulum-filled control, PRP, particulated autogenous bone alone (A), or combined with PRP (A-PRP). Results: Mean platelet concentration of 1,761,930 ± 680,200/µl was achieved (5.30 ± 2.63 × fold of baseline). Animals were sacrificed 1, 2, and 4 weeks later. Histomorpho…

Membrane potential of rat calvaria bone cells: dependence on temperature.

1990

The membrane potentials of bone cells derived from calvaria of new born rats was shown to be strongly dependent on temperature. When we lowered the temperature from 36 degrees C to 26 degrees C, cells with spontaneous resting membrane potentials (MP) of -80 to -50 mV depolarized (mean amplitude 8 mV; n = 33), and the membrane resistance increased by approximately 80% (n = 20). The temperature response depended on the actual MP, the reversal potential being in the range of -80 to -90 mV. With the application of ouabain (0.1-1 mmol/liter; n = 12), cells depolarized. Simultaneously, the reversal potential of the temperature response was shifted towards more positive values and approached the a…