SEARCH · PubMed Health

Results for “Osteogenesis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources

PubMed1995

Theory of osteogenesis behavior based on calcium diffusion theory.

Osteogenesis is completed by the nucleation mechanism on crystal nuclei formation and growth after amorphous calcium phosphate accretion to collagen fibers. For nuclei formation, it is necessary to have preliminary ionic diffusion such as that of Ca2+ and PO4(3-) ions to this part. Therefore, promotion of ionic diffusion to this part is the first essential condition for osteogenesis. We have considered this phenomenon as the nucleation mechanism accompanied by preliminary diffusion behavior and shown the optimum mechanical condition on promoting this ionic diffusion. Furthermore, we noticed callus by callotasis as the typical example which fits this mechanical condition and investigated its histology. However, necking occurs at the site of callus sandwiched by cortical bones due to tensile stress, three axial tensile stress in radial and tangential directions, in addition to the tensile stress occurs at the netsection of the callus due to the constraint of cortical bones. Therefore, the size of pore along the collagen lamination and hole zone becomes large under this mechanical condition and ionic diffusion such as Ca2+, PO4(3-) is liable to occur at this part. By solving the partial differential equation of the stress-induced diffusion, diffusive particles are shown to concentrate at the high three axial tensile stress region. Therefore, a high concentrated region of Ca, PO4 is achieved and selective osteogenesis due to hydroxyapatite nucleation is considered to progress in this region. Histological investigation of the callus of rabbit showed that mineralization occurs at this site and supports the theory of stress-induced diffusion on osteogenesis behavior.

Animals↗

PubMed1997

[Collagen analysis in fibroblasts in osteogenesis imperfecta. Clinical benefits].

We performed collagen analysis in 38 patients with osteogenesis imperfecta. In order to assess the clinical benefit of the analysis, all cases were studied retrospectively. Five patients were children with lethal osteogenesis imperfecta, in whom the diagnosis was confirmed after termination of pregnancy. In the remaining 33 patients, collagen analysis was performed because of clinical suspicion of osteogenesis imperfecta. Child abuse was suspected in seven patients. We found good correlation between the results of collagen analysis and the final diagnoses, which were based on clinical information and observation over time. In this study we also tested a set of diagnostic criteria which seem to be useful in clinical practice. The collagen analysis was of decisive diagnostic value in half (16/33) of the patients, but also in the remaining patients the clinical diagnosis was strengthened. We obtained only one false negative result. Our study indicates that in selected patients where diagnosis is difficult, collagen analysis can be an important tool in establishing the diagnosis osteogenesis imperfecta.

Adolescent↗

PubMedDate not supplied

Recent findings in classification of osteogenesis imperfecta by means of existing dental symptoms.

The findings are based on a clinical investigation conducted on forty-nine patients suffering from osteogenesis imperfecta (OI), as well as on a questionnaire study in which 117 osteogenesis imperfecta-affected persons or their parents were involved. The survey established pathological tooth discolorations as well as tooth abrasions. Dentinogenesis imperfecta (DI) was more frequently found in primary teeth than in permanent teeth. There were no gender-specific differences. Radiological abnormalities were found in both, abraded and/or discolored teeth, as well as in clinically normal appearing teeth. In most cases there were club-shaped extensions of the pulp chambers and obliterations of the root canals. The probability that dentinogenesis imperfecta occurs as an accompanying symptom of osteogenesis imperfecta was not dependent on the degree of skeletal severity. The self-assignment according to A and B forms of osteogenesis imperfecta types I and IV in accordance with the presence/absence of dental symptoms was contradictory, since the literature was based on varying classifications.

Adolescent↗

PubMed1998

The role of dual energy x-ray absorptiometry in aiding the diagnosis of pediatric osteogenesis imperfecta.

The role of dual energy x-ray absorptiometry (DEXA) in the evaluation of the pediatric patient with multiple fractures has not been well established. We retrospectively examined the medical records of 45 patients who had presented to our institution with multiple fractures of unknown cause, who were not known to have osteogenesis imperfecta, and who had obtained DEXA as part of their evaluation. Of these, 26 patients had sufficient clinical data for inclusion in this study. Patients underwent DEXA of the anteroposterior spine and whole body. A z score was calculated to normalize the DEXA values for age. The diagnosis of osteogenesis imperfecta was correlated with the outcome of each DEXA scan to assess the validity of DEXA as a diagnostic tool. The DEXA of the anteroposterior spine had the highest sensitivity at 91.7%, while DEXA of the whole body had the highest specificity at 100.0%. Decreased bone mineral density may be associated with osteogenesis imperfecta, and DEXA is helpful in detecting low bone mineral density that may be missed on plain radiographs of children with milder forms of osteogenesis imperfecta.

Absorptiometry, Photon↗

PubMed2000

Craniofacial shortening by contraction osteogenesis: an experimental model.

Application of gradual external forces to correct craniofacial deformities challenges many procedures in conventional craniomaxillofacial surgery. Distraction osteogenesis is replacing traditional osteotomies for correction of patients with craniomaxillofacial deficiencies. However, the reverse concept, contraction osteogenesis, has yet to be established for patients with craniomaxillofacial excesses. The purpose of this investigation is to demonstrate the contraction osteogenesis phenomenon applied in a controlled animal model during the craniofacial growth period. Twenty-six 26-day-old rabbits were assigned to one of four groups: 0, control; 1, pin control (pin insertion); 2, no contraction (pins and contraction device application, without active contraction); and 3, contraction (pin insertion, contraction device application, and active contraction). An external fixator was placed across the incisive-maxillary suture, and the effects after 4.5 weeks of contraction at a rate of 0.5 mm twice a week were compared with control groups. The results were assessed by craniometric and cephalometric measurements and by histologic examination. Gross alterations were evident in the contraction group, characterized by midface anteroposterior shortening, maxillary regression, snout deviation, and anterior crossbite. Histologic examination of the contraction group demonstrated a significant increase in osteoblastic activity. Contraction osteogenesis is a new treatment concept in craniofacial development and may offer therapeutic opportunities for shortening skeletal structures without the need of osteotomies, thus taking advantage of the potential of craniofacial growth and remodeling.

Animals↗

PubMed1977

Surgery and histopathology of the stapes in osteogenesis imperfecta tarda.

Fourteen stapedectomies were performed on ten patients with osteogenesis imperfecta tarda. Clinically, the footplates were softer and more tenuously fixed than in otosclerosis and floating footplates seemed more common. Stapes and stapes fragments from all 14 operations were examined microscopically. The histopathology of osteogenesis imperfecta was contrasted to that of otosclerosis. We believe that the greater degree of structural disorganization and greater area occupied by resorption spaces clearly distinguish the new bone formed in osteogenesis imperfecta from otosclerosis.

Adolescent↗

PubMed1999

Biologic model of bone transport distraction osteogenesis and vascular response.

We developed an experimental model in the rabbit of distraction osteogenesis through bone transport that closely corresponds to the clinical use of bone transport in humans. We also applied injection angiography to study the arterial response of a limb undergoing bone transport. This model includes a proximal osteotomy and bone transport to fill in a segmental tibial diaphyseal defect. Regenerate bone formed well in the gap that was created that trailed the transport segment, and slow healing at the docking site was observed, as seen in humans. The angiographic techniques clearly revealed, by radiography and anatomic dissection, the arterial response to bone transport. The results showed that the transport segment had an arterial supply after osteotomy and after transport. They also demonstrated an extensive increase in vessels in limbs that had undergone distraction osteogenesis, an observation made clinically in humans but not well demonstrated experimentally. Furthermore, angiography showed proximal stretching and distal kinking of the major artery of the leg. This model closely resembles distraction osteogenesis through bone transport in humans and definitively demonstrates that the transport segment can maintain blood supply and remain viable during the transport process. The results of this study provide a basis for further work on factors that enhance and interfere with successful bone transport in humans.

Angiography↗

PubMed2004

Creation and characterization of a mouse model of mandibular distraction osteogenesis.

While the histological and ultrastructural changes associated with distraction osteogenesis have been extensively characterized using various animal models, the molecular mechanisms governing this technique remain poorly understood. In the current study, for the first time, we describe a mouse mandibular distraction osteogenesis model. Development of this model will allow assessment of factors involved in normal vs. abnormal healing (especially in non-unions) of craniofacial skeletal elements. Complete osteotomies were created on the right hemimandibles of 51 adult male CD-1 mice and customized distraction devices attached. Thirty-three animals underwent gradual distraction (5 days latency, distraction at 0.2 mm BID x 8 days, 28 days consolidation), while the remaining 18 mice underwent acute lengthening (immediate distraction to 3.2 mm) at the time of surgery. Mandibles were harvested at time points corresponding to the latent (POD 5), distraction (POD 9, 13), and consolidation (POD 28, 41) periods and processed for histological or quantitative real-time RT-PCR analysis. Specimens from each group were processed for microCT analysis. Histological and radiological data demonstrated that all mandibles undergoing gradual distraction achieved complete bony union by the end of consolidation, while those undergoing acute lengthening formed a fibrous non-union. Quantitative real-time RT-PCR demonstrated upregulation of mRNA for VEGF, FGF-2, collagen I, and osteopontin during gradual distraction but not during acute lengthening. These data validate our novel mouse mandibular distraction model and demonstrate its utility in elucidating the molecular mechanisms regulating bone formation during distraction osteogenesis as compared to those that are expressed during the formation of fibrous non-unions.

Animals↗

PubMed2006

A new approach to repairing cleft palate and acquired palatal defects with distraction osteogenesis.

Cleft palate (CP) is one of the most common human congenital deformities, and acquired palate defects after trauma or tumour resection are also common. In this study, distraction osteogenesis (DO) for CP and other palatal bone defects was evaluated. Twenty cats were assigned randomly to 3 groups of (1) 15, (2) 3 and (3) 2 cats. In groups 1 and 2, a rectangular ostectomy, in the posterior of the palatal bone shelf, was performed in the sagittal axis to establish the CP defect model. At the same time, a pure titanium intraoral distractor was fixed to molar teeth with brackets and to the palatal bone shelf across the defect with titanium miniscrews bilaterally. Four weeks later, a secondary transport disc (TD) osteotomy was performed, and gradual DO treatment started at 0.4mm twice a day, after 6 days of latency. DO was performed until the TD reached the opposite margin over the gap in 5-6 days. Three cats each of group 1 were killed at 2, 4, 6, 8 and 12 weeks after completion of DO. In group 2, the bone and soft-tissue defects were untreated until death 6 weeks later. Group 3 cats (control) were killed after 6 weeks. The TD successfully recombined with the opposite palatal bone stump, and proportional expansion of the overlay mucoperiosteal flap was achieved. Intramembranous bone formation was revealed: parallel collagen bundles gradually deposited on new bone trabeculae while the proliferative osteoblasts produced bone matrix. The bone defect was finally reconstructed by de novo osteogenesis. The control group was observed to have no spontaneous repairing. These results suggest that the CP defect was reconstructed by osteogenesis in situ, and the soft tissues expanded simultaneously to achieve functional correction. The intraoral distractor provided both effective distraction and stability.

Animals↗

PubMed2004

Distraction osteogenesis in the Cbfa-1+/- mouse.

Distraction osteogenesis involves division of a bone and gradually pulling the bone ends apart. This delivers mechanical stimulation to mesenchymal cells in the distraction gap, where new bone is regenerated predominantly by intramembranous ossification. The transcription factor Cbfa1 has been reported to be essential for the differentiation of mesenchymal cells to osteoblasts. In homozygous Cbfa1 knockout mice, both intramembranous and endochondral ossification mechanisms are blocked and no bone formation occurs. In heterozygous Cbfa1 knockout mice, only the cranial bones and the clavicles, which form through intramembranous ossification, fail to develop properly as in the human condition of cleidocranialdysostosis. It has been suggested, therefore, that intramembranous ossification is affected by the absence of one of the paired Cbfa1 genes. We have assessed the potential for intramembranous ossification following distraction osteogenesis in heterozygous Cbfa1 knockout mice. Fourteen skeletally mature male heterozygous mice were used, together with 10 wild-type controls. The tibia was distracted by 0.25 mm twice a day (0.5 mm/day) for 10 days using the half-ring type fixator. Nine mice were kept for a further 28 days to observe the consolidation phase. In four out of five mice of the heterozygous group and in all three wild-type mice, bony fusion within the distraction gap was observed on radiographs. Histological findings were almost the same in the two groups at various stages of the procedure and intramembranous ossification was predominant in both the groups. Despite the inhibition of intramembranous ossification during the foetal development of Cbfa1+/- mice, distraction osteogenesis was as successful as in control mice.

Animals↗

PubMed2002

Bone consolidation is enhanced by rhBMP-2 in a rabbit model of distraction osteogenesis.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is a differentiation factor which has been shown to induce bone formation and heal bony defects in a variety of animal models. A possible application of rhBMP-2 is to accelerate bone regeneration during distraction osteogenesis. which clinically is a long procedure, often involving significant complications. In this study we tested the ability of rhBMP-2 to accelerate the consolidation phase of distraction osteogenesis in a rabbit model of leg lengthening. Tibiae were lengthened 2 cm over a period of ten days. rhBMP-2 was administered at the end of the lengthening phase. Two modes of rhBMP-2 application were tested: surgical implantation of rhBMP-2/ACS (absorbable collagen sponge) into the regenerate (50 microl of 1.5 mg/ml rhBMP-2, total dose = 75 microg rhBMP-2), and percutaneous injection of rhBMP-2/buffer (0.1 ml of 0.75 mg/ml rhBMP-2. total dose = 75 microg rhBMP-2) into three sites within the regenerate. Also, there were three groups of control animals: (1) no surgical intervention, (2) surgical implantation of buffer/ACS and (3) percutaneous injection of buffer. Rabbits were sacrificed at 5, 14 and 28 days after the interventions. Radiographic evaluation indicated a significant increase in bony union of the distraction regenerate in the rhBMP-2 treated groups compared with the untreated groups at 5 and 14 days. At 28 days, formation of a cortex and reestablishment of the medullary canal was evident only in the rhBMP-2 treated groups. The bone mineral content (BMC) of the regenerate was significantly higher in the rhBMP-2 treated groups at 5 and 14 days. However, at 28 days, BMC of the regenerate was similar in all groups. The average volumetric density of the regenerate was significantly higher in the rhBMP-2 injection group at day 14. In Summary, both injection of rhBMP-2/buffer and implantation of rhBMP-2/ACS enhanced the consolidation stage of distraction osteogenesis in this rabbit model.

Animals↗

PubMed2003

Temporospatial expression of vascular endothelial growth factor and basic fibroblast growth factor during mandibular distraction osteogenesis.

OBJECTIVE: Distraction osteogenesis is a vascular-dependent process. This study investigated expression patterns of two major angiogenic factors, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), in the distracted calluses following mandibular lengthening in a goat model. MATERIAL AND METHODS: Bilateral mandibular osteotomies were performed in 15 young adult goats. After a latency of 7 days, the mandibles were elongated using custom-made distractors with a rate of 1 mm/day for 10 days. Three animals each were sacrificed at the end of the delay phase, at 0, 7, 14, and 28 days after completion of distraction, respectively. The lengthened mandibles were harvested and processed for histological and immunohistochemical examinations. RESULTS: Elevated cellular expression of VEGF and bFGF, with neovascularization in the distraction gap, was observed following mandibular lengthening. VEGF staining was noted in the endothelial cells and osteoblasts. bFGF staining was seen in the fibroblast-like cells, osteoblasts and immature osteocytes. Their strongest expression was found 0-7 days after the end of distraction, and declined with maturation of the newly formed bone. CONCLUSION: A temporal and spatial expression pattern of VEGF and bFGF was found during distraction osteogenesis in goat mandibles. It suggests that distraction forces can stimulate the production of VEGF and bFGF, which contribute to neovascularization and new bone formation during gradual distraction of the mandible. Application of angiogenic factors may be considered as a potential method to enhance angiogenesis and osteogenesis in osteodistraction, especially in sites without enough vascularization.

Animals↗

PubMed2002

Osteoblastic activity of the rabbit temporomandibular joint during distraction osteogenesis assessed by [18F]fluoride positron emission tomography.

The purpose of the study was to evaluate the effects of irradiation and hyperbaric oxygenation (HBO) on osteoblastic activity of the temporomandibular joint (TMJ) region during mandibular distraction osteogenesis. Unilateral distraction was performed on 19 rabbits, which were divided into five groups. One group served as a control group, while the others received either high- or low-dose irradiation in the TMJ region before surgery. Some of the animals were also given HBO 18 times at 2.5 ATA x 90 min preoperatively. Osteogenesis was assessed by [18F]fluoride positron emission tomography at the end of the distraction. Osteoblastic activity was higher on the distracted side in all groups, except in the high-dose irradiated group without preceding HBO. HBO increased osteogenesis on both sides after radiotherapy. It is concluded that increased osteoblastic activity reflects increased pressure on the TMJ region of the distracted side, resulting from lengthening. It seems that more remodeling is required after irradiation than without preceding radiotherapy. After radiotherapy, HBO increased osteoblastic activity.

Analysis of Variance↗

PubMed2000

In vitro analysis of distraction osteogenesis.

Distraction osteogenesis has been widely used for lengthening craniomaxillofacial bone. The healing process of distracted bone has been studied mainly by histological observation in vivo. To analyze the cellular response to the mechanical stress of distraction, we have established and evaluated an in vitro model of distraction osteogenesis using an organ culture technique. Five-week-old male Wistar rats were used for the experiments. The tibial bone was fractured by hand and fixed for 1 week by acrylic resin. After the initial healing period, the tibial bone was harvested and used for this study. A distraction instrument was devised to control the strain on the cultured bone using a micrometer. After distraction, the samples were histologically evaluated for ossification by hematoxylin and eosin stain and Alcian blue stain. As a result, the histological finding for the bone region at a slow rate of distraction (0.5 mm/day) was different from that at a rapid rate of distraction (1.0 mm/day). The proliferation of cartilage was inhibited at the rapid distraction rate. Thus, we hypothesized that mechanical stress regulated cartilaginous growth in tissue cultivation. Judging from this experiment, the model was useful for investigation of the mechanism of bone formation in distraction osteogenesis, because it was simple and served to isolate many factors.

Acrylic Resins↗

PubMed2001

Distraction osteogenesis of the craniofacial skeleton.

Distraction osteogenesis is becoming the treatment of choice for the surgical correction of hypoplasias of the craniofacial skeleton. Its principle is based on the studies of Ilizarov, who showed that osteogenesis can be induced if bone is expanded (distracted) along its long axis at the rate of 1 mm per day. This process induces new bone formation along the vector of pull without requiring the use of a bone graft. The technique also provides the added benefit of expanding the overlying soft tissues, which are frequently deficient in these patients. This article reviews the authors' 11-year clinical and research experience with mandibular distraction osteogenesis. It highlights the indications and contraindications of the technique and emphasizes the critical role that basic science research has played in its evolution.

Aging↗

PubMed2006

Effect of recombinant human bone morphogenetic protein-2 on mandibular distraction osteogenesis.

The purpose of this investigation was to study the effects of recombinant human bone morphogenetic protein-2 (rhBMP-2) on bone formation of mandibular distraction osteogenesis. Six skeletally mature sheep underwent 10 mm of bilateral mandibular distraction osteogenesis via a custom-made distractor. Three micrograms of rhBMP-2 with a collagen carrier was implanted in the osteotomy site of one side of the mandible during the osteotomy phase. The contralateral side was used as the control group, and no material was implanted into the distracted area. At 10 days after the end of distraction, all animals were killed, and the distracted calluses were harvested for radiologic and histologic analysis. New bone was generated in the distracted zone in all groups. Histologic and radiologic examination showed that the new bone formation was greater in the rhBMP-2 group than in the control group. Quantitative computed tomography evaluation, however, did not demonstrate a significantly different mean bone density of the regenerates between the 2 groups. The results indicate that application of a rhBMP-2/collagen implant during the osteotomy phase of distraction osteogenesis increased bone formation but did not have a significant effect on bone density of the regenerates.

Animals↗

PubMed2006

Intermittent loading improves results in mandibular alveolar distraction osteogenesis.

AIM: To evaluate clinical and morphological effects on distractive callus after application of an original protocol of bone stimulation. MATERIAL AND METHODS: Traditional or mechanically stimulated alveolar-distraction osteogenesis was studied on 16 highly selected subjects subdivided into two groups. Clinical, radiological, densitometric and histological (on biopsies) analyses were performed 6, 8 and 12 weeks after distraction was completed. RESULTS: In subjects undergoing stimulated alveolar-distraction osteogenesis, bone density was higher and at histology, bone with ordered structure was observed after 6 weeks. Moreover, bone trabeculae with oriented architecture and greater amounts of lamellar bone were observed after 8 and 12 weeks in the same subjects. DISCUSSION AND CONCLUSIONS: In conclusion, although osteogenic processes were similar in both groups, they were induced earlier and were better structured in subjects undergoing stimulated alveolar-distraction osteogenesis. These encouraging results can only be achieved and preserved by strict monitoring of distractive vectors.

Absorptiometry, Photon↗

PubMed2006

Formation of new bone during vertical distraction osteogenesis of the human mandible is related to the presence of blood vessels.

We examined the effect of distraction rate on blood vessel growth in intramembraneous ossification after vertical distraction osteogenesis in the human mandible. Six edentulous patients (aged 60+/-9 years) with a severely atrophic mandible underwent bone augmentation with distraction osteogenesis. Two distraction rates (0.5 and 1 mm/day) were compared and for each group three patients were analyzed. Vascular histomorphometry was carried out in two different areas in the distraction gap: (1) in the first and (2) in the second 1 mm area from the osteotomy line, representing the oldest and younger new-bone area, respectively. Correlation analysis was performed between blood vessel parameters and the amount of new bone formed during distraction. Histological analysis demonstrated the presence of blood vessels throughout the soft connective tissue in the distraction gap. The volume density of blood vessels between the two investigated areas was significantly lower in the 1 mm/day groups, suggesting a delay in angiogenesis in this group of patients. A positive correlation between blood vessel volume and bone volume density was found in the younger new-bone area but not in the oldest new-bone area. This correlation was due to a higher number of blood vessels rather than to a larger size of the blood vessels. Our data suggest that the lower blood vessel density found in the patients with 1 mm/day distraction rate may be related to disruption of angiogenesis in the soft connective tissue of the gap or to a less optimal mechanical stimulation of cells involved in angiogenesis. This probably results in the slower rate of osteogenesis seen at the 1 mm/day distraction rate compared with the 0.5 mm/day distraction rate. The data support the concept that a positive relationship exists between the density of blood vessels and the formation of bone. For distraction of the human mandible in elderly patients, a distraction rate of 0.5 mm/day seems beneficial.

Age Factors↗