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PubMed1980

Regeneration of bone in the presence of calcium sulfate.

I describe 110 patients in whom diseased and destructed bone was restored to normal healthy bone. The first ten patients were healed by using bismuth-iodoform, and the following 100 patients were treated using the hemihydrate of calcium sulfate (CaSO4.2H3O). Both alloplasts were replaced in all patients by normal healthy cancellous bone within two to four months. It is a safe procedure in which bone regeneration is stimulated to a maximum rate. During June 1974, bismuth-iodoform was used as an allograft. On July 9, 1974, the first three operations in the history of otorhinolaryngology, to my knowledge, were performed using CaSO4. Normal physiologic absorption of CaSO4 occurs with the simultaneous deposition of autogenous cancellous bone. Calcium sulfate is an outstanding bone substitute, ensuring bone formation and giving results comparable with autogenous bone, if not better.

Adolescent↗
PubMed2001

Transplantation of labeled periodontal ligament cells promotes regeneration of alveolar bone.

Regeneration of damaged periodontal tissues is mediated by periodontal cells, but a major sub-population comprises highly differentiated cells that do not renew. To overcome the loss of specialized cell types caused by disease, various therapeutic approaches including cell transplants have been developed to promote cell re-population in periodontal tissues. As previous transplantation studies used unlabeled cells, that are indistinguishable from host cells, it has been difficult to assess the contributions of transplanted cells to the healing processes. To track the fate and differentiation of rat periodontal cells transplanted into periodontal wounds, we used collagen-coated fluorescent beads as a permanent endocytosed marker, or cells constitutively expressing beta-galactosidase. We assessed osteogenic cell differentiation with immunohistochemical staining for osteopontin and bone sialoprotein. Cells were transplanted into periodontal wounds created in Sprague--Dawley male rats that are null for beta-galactosidase. Defects were allowed to heal spontaneously (controls), or were closed with collagen implants mixed with beta-galactosidase-positive (Lac-Z) periodontal cells, or closed with collagen implants mixed with periodontal cells loaded with fluorescent beads. Animals were killed at 1 and 2 weeks after surgery and tissues were prepared for morphometric assessment and immunostaining for osteopontin (OPN) and bone sialoprotein (BSP). Transplanted cells were easily distinguished by fluorescent beads or by beta-galactosidase-positive expression and were distributed throughout the regenerating periodontal ligament (PL) and alveolar bone. At 1 week after wounding, animals treated with beta-galactosidase-positive cells exhibited a slightly higher percentage of labeled cells in the PL compared with the fluorescent bead-labeled cell implant group (2% vs. 1% respectively; P > 0.2). At Week 2 percentages of labeled cells were slightly increased in the regenerating PL (approximately 3% for both groups, P > 0.2). In regenerating alveolar bone at 1 week, animals that were treated with beta-galactosidase-positive cells and fluorescent bead-loaded cells exhibited approximately 30% and 25% of labeled cells respectively. At 2 weeks after wounding there was an increase in the percentage of transplanted beta-galactosidase-positive cells (approximately 39% at week 2; P < 0.05), but not of transplanted cells with fluorescent beads (approximately 25% at week 2). In sites with transplanted cells there were higher percentages of OPN positive and BSP positive cells in nascent bone and more newly formed bone than in controls (>40%; P < 0.05). Transplantation of beta-galactosidase-positive cells or cells loaded with fluorescent beads is a useful method for assessing the fate and differentiation of periodontal cells in vivo. Fluorescent beads, however, are diluted at mitosis and this method underestimates the percentage of transplanted cells. As transplanted periodontal cells in both groups promoted regeneration of alveolar bone, cell transplantation could improve the restoration of periodontium destroyed by periodontitis.

Alveolar Bone Loss↗
PubMed1998

Influence of surface microstructure on the reaction of the active ceramics in vivo.

When porosity and macro-pore size differ in the same ceramic, the mode of bone regeneration and the degradation of ceramics in vivo is said to be different. However, the reactions in vivo of ceramics that have a different microstructure with the same porosity and the same macro-pore size, are not so far known. In this study, two kinds of beta-tricalcium phosphate (TCP) that had different microstructures but the same porosity and macro-pore size, were manufactured. These TCP were implanted in the distal femurs of 20 mature male rabbits, and their respective areas of ceramics and of regenerated bone were measured after 4, 12 and 24 wk. In both TCPs, the regenerated bone similarly decreased from 4-24 wk in a different way. The area of ceramics in one of these TCPs significantly decreased gradually throughout the observation period. On the other hand, the other TCP showed no marked decrease during the same period. This suggested a possibility that the difference in micro-structure has a large effect on the reaction of the ceramics in the bone.

Journal Article↗
PubMed2001

Bone repair of experimentally induced through-and-through defects by Gore-Tex, Guidor, and Vicryl in ferrets: a pilot study.

OBJECTIVE: The purpose of this pilot study was to evaluate whether improved bone regeneration can be achieved in experimentally induced through-and-through mandibular defects in ferrets and whether there is a quantitative and qualitative difference of regenerated bone with different guided tissue regeneration membranes. STUDY DESIGN: Through-and-through osseous defects were created at the apices of 16 mandibular premolars of 8 ferrets. The transosseous defects were covered with Gore-Tex, Vicryl, or Guidor membranes. As control, the defects were covered with mucoperiosteal flaps without any membranes. RESULTS: The control group showed ingrowth of sulcular epithelium into the defect. The Gore-Tex group showed good bone formation, whereas the Vicryl group showed the highest degree of bone formation. Six weeks after the operation, the defect had nearly completely filled with fibered and lamellar bone. Twelve weeks after the operation, mainly lamellar bone was observed. In contrast, the Guidor group was found to have limited bone regeneration. CONCLUSION: The results of this in vivo study suggest that guided tissue regeneration membranes generally promote and improve bone regeneration in osseous defects of endodontic origin.

Animals↗
PubMed2000

[Study on regeneration of mandibular bone with bioabsorbable organic/inorganic composite membrane].

Guided bone regeneration (GBR) has attracted much attention as a means to treat bone defects and congenital malformation. However, presently available materials are not ideal and further improvements are necessary. Hence we have been developing a novel bioabsorbable composite material beta-TCP/CPLA for the GBR technique. The polymeric matrix is a copolymer of poly-L-lactide acid and fatty polyester (CPLA) that is biodegradable by hydrolysis, and the ceramic filler is beta-tricalcium phosphate (beta-TCP) that is bioabsorbable and has good osteoconductivity. The materials were evaluated by in vivo and in vitro experiments. Furthermore, animal experiments with mandibular bones defects in dogs were carried out. Good bone regeneration was observed in the case of the treatment with beta-TCP/CPLA membrane whereas almost no bone regenerated in the cases without the membrane. beta-TCP/CPLA membranes were suggested to have promising properties for bone defect treatment.

Absorbable Implants↗
PubMed1992

Regenerative response to membranous and enchondral lyophilized allogeneic bone in rabbit skull defects.

The regenerative responses of inlays of lyophilized allogeneic bone of membranous (skull) and enchondral (tibia) origin were studied in an experimental cranioplasty model in rabbits. The lyophilized bone particles were also bioassayed for inductive bone production in an orthotopic critical size defect rat model. Three trephined calvarial defects were evaluated in each of 14 adult rabbits. The experimental materials were implanted into two of the defects and the third was left empty for control purposes. The implants disclosed no major structural divergences as assessed by scanning electron microscopy. Healing was evaluated by light microscopy and contact radiography after periods of four and 15 weeks. The lyophilized bone allografts of both embryonic origins displayed a similar fashion of bone regeneration, bone marrow reappearance, and volumetric density of trabecular bone substance and displayed no obvious differences between experimental groups or intervals. The two materials exhibited low osteoinductive potential.

Animals↗
PubMed2000

Long-term evaluation of osseointegrated implants in regenerated and nonregenerated bone.

This investigation evaluated the predictability of dental implants subjected to bone regeneration procedures at the time of insertion. Fifty-two test implants were inserted into sites with periimplant bone defects. A calcium carbonate allograft material with or without a fibrin-fibronectin sealing system was used to fill the defects. Sixty control implants were inserted into an adequate volume of nonaugmented bone. Each of the 29 study patients received at least one test implant and one control implant. At the second-stage surgery, fill of the bone defect was assessed as complete or incomplete. The cumulative success rate was 91.7% (mean follow-up 55 mo) for the test implants and 93.2% (mean follow-up 59 mo) for the control implants. Within the test group, implants with complete bone fill achieved 97.6% success versus 59.1% success for implants with incomplete bone fill. These preliminary results suggest that implants placed with simultaneous bone regeneration procedures achieve long-term predictability that is comparable to that of implants placed in an adequate volume of bone, provided that complete bone fill of the periimplant defect is achieved. Long-term studies with other augmentation materials are needed to fully validate these findings.

Alveolar Bone Loss↗
PubMed1993

Influence of indomethacin on the regeneration of cortical bone within titanium implants in rabbits.

The influence of indomethacin on cortical bone regeneration was studied in bone harvest chambers made of commercially pure titanium and inserted in rabbit tibia. Newly formed bone was harvested in situ every 3 wk for 33 wk. Indomethacin (1 mg/kg body weight) was given daily as subcutaneous injections for two periods, followed by two control periods with no drug administration and the same schedule was followed for indomethacin at a dose of 4 mg/kg body weight. These indomethacin dosages did not statistically influence the cortical bone regeneration.

Analysis of Variance↗
PubMed1998

Histochemical and molecular analyses of distraction osteogenesis in a mouse model.

A tibial lengthening scheme in the mouse was used to study the molecular and cellular events regulating tissue regeneration during distraction osteogenesis. Here, we report on the surgical technique and frame design and describe the histochemical and molecular aspects of distraction during different phases of treatment. A total of 26 mice were used in this study. The treatment protocol was divided into a latency period of 7 days, a phase of active distraction that lasted 10 days with a distraction rate of 0.42 mm/day, and a maturation phase of 9 days. During latency, the distraction site resembled a stabilized fracture callus on both a histochemical and a molecular level. During active distraction, the gap was characterized by a central fibrous interzone bordered by primary matrix fronts, regenerate bone aligned with the distraction force, parallel columns of vascular sinusoids, and a medullary cavity. Alkaline phosphatase activity was detected in the endosteal and periosteal surfaces of the bone ends. Tartrate resistant acid phosphatase staining revealed that osteoclasts remodeled the bone regenerate as it formed. Collagen type I was expressed in the periosteum and the primary matrix front during distraction, whereas collagen type-II transcripts were localized to discrete regions on the periosteal surfaces, immediately adjacent to the osteotomy ends. Collagen type-II transcripts were not detected in the fibrous interzone. During the maturation phase, cells within the fibrous interzone expressed collagen type I and exhibited abundant alkaline phosphatase activity, suggesting that they had begun to terminally differentiate. Collectively, these data demonstrate the utility of a mouse model to study the molecular and cellular bases for the regeneration and remodeling of tissue.

Acid Phosphatase↗
PubMed2002

Differences in mandibular distraction osteogenesis after corticotomy and osteotomy.

Corticotomy or osteotomy was performed on opposing sides of the mandibles in 18 goats. A custom-made distractor was used to lengthen the mandible at a rate of 1 mm/day for 10 days (total 10 mm elongation). Six goats were sacrificed respectively at 2, 4 and 8 weeks after completion of distraction. The distracted calluses were harvested and processed for radiographic, histologic, and scanning electron microscopic evaluation as well as Ca/P ratio analysis. The regenerate bone in the corticotomy side showed more bone formation and earlier mineralization than in the osteotomy side. The results of this study suggest that preservation of intramedullary vessels is beneficial to bone regeneration following mandibular osteodistraction, and that performing corticotomy may be a simple but effective way to promote the maturity of the distracted callus and shorten the time for fixation.

Animals↗
PubMed1990

Limb lengthening and three-dimensional deformity corrections. A retrospective clinical study.

Different methods of limb lengthening as used at the Orthopedic Surgery Clinic of the Medical School, University of Zagreb, are compared. The results of operations performed between 1979 and 1989 on 111 patients are presented. These patients were subjected to surgery aimed at length equalization of limbs and/or correction of three-dimensional deformities. Lengthening was performed in 104 patients at one level, and in 7 patients at two levels of the same limb for a total of 118 procedures. In order to compare limb lengthening techniques the patients were divided into four groups: group I, original Wagner technique (45 patients); group II, Wagner technique using corticotomy (33 patients); group III, original Ilizarov technique (35 patients); group IV, continuous lengthening (2 patients). The evaluation covered radiological aspects of regenerated bone, complications and basic lengthening parameters. The results indicate that corticotomy has considerable advantages over osteotomy, provided bone circulation is maintained. These advantages manifest themselves in a reduced number of operations, lower incidence of infection and improved bone regeneration. It is preferable to perform corticotomy at the metaphysis site because of its optimum blood supply and its higher potential for osteogenesis. With corticotomy performed at the diaphysis site, satisfactory results were observed in only one-third of the cases.

Adolescent↗
PubMed1998

The effect of transforming growth factor beta one (TGF-beta 1) on wound healing, with or without barrier membranes, in a Class II furcation defect in sheep.

The purpose of this study was to analyse the effect of TFG-beta 1 on wound healing in standardized Class II furcation defects of 48 mandibular second premolar teeth in 24 sheep. The experimental design included a control group (carrier only, 25% pluronic F-127), and 2 experimental groups: group A (80 micrograms/ml TGF-beta 1 + carrier) and group B (80 micrograms/ml TGF-beta 1 + carrier covered with a barrier membrane). Sheep were killed either 2 wk or 6 wk after surgery. Mesiodistal sections of the decalcified specimens were quantified histologically using stereology. Percentage volumes of regenerated bone, fibrous connective tissue and cementum were calculated for each furcation defect. Mean values were analysed using multiple ANOVA; p values were calculated using paired and unpaired Student's t-tests. After 2 wk there was more bone in group B than either of the other 2 groups, but this was not statistically significant. By 6 wk more bone was present in group A than in the control group (p < 0.02) and also in group B when compared with both group A and the control group (p < 0.02 and p < 0.44), respectively. In the 4 wk between sampling significantly more bone had formed (group A < 0.05 and group B p < 0.003, respectively). A negative correlation existed between volumes of bone and fibrous connective tissue and no significant differences between the volumes of cementum were evident between any of the groups. This study demonstrated that TGF-beta 1 encouraged bone regeneration in Class II furcation defects in sheep, an effect enhanced by the presence of a barrier membrane. This is the first report on the use of TGF-beta 1 in conjunction with GTR in periodontal defects.

Alveolar Process↗
PubMed1997

A radiographic study of recurrent unicystic ameloblastoma following marsupialization. Report of three cases.

OBJECTIVES: To study the radiographic sequence in the recurrence of unicystic ameloblastoma following marsupialization. MATERIALS AND METHODS: Retrospective analysis of three cases of uncystic ameloblastoma. RESULTS: Six distinct stages were identified in all three cases: bone regeneration starting at the periphery of the cavity; appearance of a diffusely sclerotic band; appearance of scalloping; expansion of scalloping; formation of a multilocular pattern; and enlargement of the cystic lesion. CONCLUSION: The first radiographic sign of recurrence is scalloping of the sclerotic margin of the regenerated bone.

Adult↗
PubMed2003

Effect of recombinant human bone morphogenetic protein-4 with carriers in rat calvarial defects.

BACKGROUND: Bone morphogenetic proteins (BMPs) are being evaluated as candidates for periodontal and bone regenerative therapy. However, the research on recombinant human bone morphogenetic protein-4 (rhBMP-4) has been insufficient to evaluate its capacity to enhance bone formation and its carrier system. The purpose of this study was to evaluate the bone regenerative effect of rhBMP-4 delivered with an absorbable collagen sponge (ACS) or beta-tricalcium phosphate (beta-TCP). We also compared the potential of beta-TCP to that of ACS as a carrier system for rhBMP-4. METHODS: Eight-mm calvarial critical-sized defects were created in 100 male Sprague-Dawley rats. The animals were divided into 5 groups of 20 animals each. The defects were treated with rhBMP-4/ACS (rhBMP-4 at 0.05 mg/ml), rhBMP-4/beta-TCP (rhBMP-4 at 0.05 mg/ml), ACS alone, beta-TCP alone, or left untreated for surgical control. The rats were sacrificed at 2 or 8 weeks postsurgery, and the results were evaluated radiodensitometrically, histologically, and histomorphometrically. RESULTS: The results of radiodensitometric analysis were as follows: the rhBMP-4/ACS and the rhBMP-4/beta-TCP groups were more radiopaque than other groups at both 2 and 8 weeks (P < 0.01). The histologic observations were as follows: in the rhBMP-4/ACS and the rhBMP-4/beta-TCP groups, new bone was evident at the defect sites at 2 weeks and 8 weeks. The results of histomorphometric analysis were as follows: the rhBMP-4/ACS and the rhBMP-4/beta-TCP groups had more bone (%) than other groups at both 2 and 8 weeks (P < 0.01). CONCLUSIONS: Surgical implantation of rhBMP-4/ACS may be used to support bone regeneration in the rat calvarial critical-sized defect, and rhBMP-4/beta-TCP may be able to regenerate bone in the rat calvarial critical-sized defect without complication. In addition, both ACS and beta-TCP may be considered as available carriers for rhBMP-4.

Absorptiometry, Photon↗
PubMedDate not supplied

[Platelet rich plasma (PRP): potentialities and techniques of extraction].

This paper describes the various techniques of platelet-rich plasma (PRP) extraction codified in recent years and their use potential is evaluated. PRP is one of the techniques with which at the moment it is attempted to modulate and facilitate the cure of a wound. The use of PRP is based on the theoretical premise that by concentrating platelets the effects of the growth factors (PDGF, TGF-beta, IGF-I and -II) so released will be increased. Marx's original technique is described above all. This prescribes the sampling of a unit of blood (450-500 ml) and the use of a cell separator. We then analysed the technique of Marx and Hannon in which the quantity of blood sampled is reduced to 150 ml, and the two simplified techniques of the Sacchi and Bellanda group. Finally, a new PRP extraction technique is described. We conclude that platelet gel allows access to autologous growth factors which by definition are neither toxic nor immunogenic and are capable of accelerating the normal processes of bone regeneration. PRP can thus be considered a useful instrument for increasing the quality and final quantity of regenerated bone in oral and maxillo-facial surgery operations.

Biological Products↗
PubMed1996

GBR with an e-PTFE membrane associated with DFDBA: histologic and histochemical analysis in a human implant retrieved after 4 years of loading.

As a result of a fracture to the cemented post and core, a pure titanium implant was extracted from a 54-year-old patient after 4 years of clinical loading. At implantation, the implant was positioned into an extraction socket and the defect was treated with an e-PTFE membrane associated with a DFDBA graft. At retrieval the implant underwent histologic and histochemical examination to assess the characteristics of the regenerated bone after 4 years of prosthetic loading. The implant showed an angular bony defect at the smooth collar, but the bone-implant direct contact rate seemed to be elevated in the remaining implant surface. Normal transmitted and polarized light examinations demonstrated that most of the DFDBA particles were resorbed and substituted by vital newly formed bone. The regenerated bone appeared compact with secondary osteons and large haversian canals; however, some partially mineralized remnants residuated in the spaces, between the osteons. Within the limits of this study, the authors concluded that DFDBA can be substituted by the host bone, but the rate of substitution is very slow and not complete after 4 years. From a clinical point of view, however, the load-bearing capacity of the bone regenerated with the membrane technique associated with DFDBA appeared to be similar to that of normal bone.

Alveolar Bone Loss↗
PubMed1981

Post-irradiation thymocyte regeneration after bone marrow transplantation. I. Regeneration and quantification of thymocyte progenitor cells in the bone marrow.

Growth kinetics of the donor-type thymus cell population after transplantation of bone marrow into irradiated syngeneic recipient mice is biphasic. During the first rapid phase of regeneration, lasting until day 19 after transplantation, the rate of development of the donor cells is independent of the number of bone marrow cells inoculated. The second slow phase is observed only when low numbers of bone marrow cells (2.5 x 10(4)) are transplanted. The decrease in the rate of development is attributed to an efflux of donor cells from the thymus because, at the same time, the first immunologically competent cells are found in spleen. After bone marrow transplantation the regeneration of thymocyte progenitor cells in the marrow is delayed when compared to regeneration of CFUs. Therefore, regenerating marrow has a greatly reduced capacity to restore the thymus cell population. One week after transplantation of 3 x 10(6) cells, 1% of normal capacity of bone marrow is found. It is concluded that the regenerating thymus cells population after bone marrow transplantation is composed of the direct progeny of precursor cells in the inoculum.

Animals↗