Histological and radiological changes in cranial bone in the presence of bone wax

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alveolar osseous defect in rat for cell therapy. Preliminary report

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Implantes de resina de poliuretana vegetal (Ricinus communis) na tração linear, fixação e fusão vertebral no cão: estudo experimental

Placa e espaçador de polímero derivado do óleo de mamona (PDOM) (Ricinus communis) foram avaliados clínica, radiográfica e histologicamente na tração linear, fixação e fusão vertebral cervical em 20 cães adultos, sem raça definida, pesando entre 17 e 22kg. Foram sacrificados quatro animais aos 10, 30, 60, 90 e 120 dias de pós-operatório. Após exposição da coluna cervical, por acesso ventral, o disco intervertebral de C4-C5 foi fenestrado e a abordagem ao canal medular foi feita por meio de fenda óssea. Um espaçador de PDOM foi colocado preenchendo o defeito ósseo. Os corpos vertebrais C4-C5 foram fixados com placa do mesmo material, utilizando-se dois parafusos corticais em cada corpo vertebral. Apenas um animal apresentou déficit neurológico no pós-operatório imediato. Radiograficamente as vértebras mostravam-se normais e alinhadas, sem colapso do espaço intervertebral, porém não houve neoformação óssea entre as vértebras. Ao exame mielográfico, não houve compressão da medula espinhal. Os implantes foram efetivos em manter a tração linear e fixação das vértebras cervicais e não ocorreu a fusão vertebral.

Utilization of autogenous bone, bioactive glasses, and calcium phosphate cement in surgical mandibular bone defects in Cebus apella monkeys

Purpose: the purpose of the present study was to evaluate the histologic results of bone cavities that were surgically created in the mandibles of Cebus apella monkeys and filled with autogenous bone, PerioGlas, FillerBone, or Bone Source. Materials and Methods: Surgical cavities 5 mm in diameter were prepared through both mandibular cortices in the mandibular angle region. The cavities were randomly filled, and the animals were divided into groups according to the material employed: Group 1 cavities were filled with autogenous corticocancellous bone; group 2 cavities were filled with calcium phosphate cement (BoneSource); and group 3 and group 4 cavities were filled with bioactive glass (FillerBone and PerioGlas, respectively). After 180 days the animals were sacrificed, and specimens were prepared following routine laboratory procedures for hematoxylin/eosin staining and histologic evaluation. Results: the histologic analysis showed that autogenous bone allowed total repair of the bone defects; bioactive glasses (FillerBone and PerioGlas) allowed total repair of the defects with intimate contact of the remaining granules and newly formed bone; and the cavities filled with calcium phosphate cement (BoneSource) were generally filled by connective fibrous tissue, and the material was almost totally resorbed. Discussion: the autogenous bone, FillerBone, and PerioGlas provided results similar to those in the current literature, showing that autogenous bone is the best Choice for filling critical-size defects. Synthetic implanted materials demonstrated biocompatibility, but the bioglasses demonstrated osteoconductive activity that did not occur with calcium phosphate (BoneSource). Conclusion: According to the methodology used in this study, it can be concluded that the utilization of autogenous bone and bioactive glasses permitted the repair of surgically created critical-size defects by newly formed bone; the synthetic implanted materials demonstrated biocompatibility, and the bioactive glasses demonstrated osteoconductive activity. The PerioGlas was mostly resorbed and replaced by bone and the remaining granules were in close contact with bone; the FillerBone showed many granules in contact with the newly formed bone; BoneSource did not permit repair of the critical-size defects, and the defects were generally filled by connective fibrous tissue.

Tissue response to polyanionic collagen: elastin matrices implanted in rat calvaria

The tissue response to polyanionic collagen matrices, prepared from bovine pericardium and implanted subperiosteally in rat calvaria, was studied. The materials were implanted in 72 male rats (Rattus norvegicus, albinus, Holtzman), randomly divided into four groups: GI-MBP hydrolyzed for 24 h; GII-MBP hydrolyzed for 36 h; GIII-MBP hydrolyzed for 48 h; GIV-native M BP. The materials were explanted after 15, 30 and 60 days and analyzed by routine histological procedures. Except for group IV (native bovine pericardium), polyanionic collagen from groups GI, GII and GIII showed low inflammatory reaction associated with bone formation, partially or completely integrated to the cranial bone; group GIV was characterized by an intense inflammatory reaction with occasional dystrophic mineralization and with occasional bone formation at 60 days when there was a decrease in the inflammatory reaction. Thus, the MBP from groups I, II and III were biologically compatible, enhancing bone formation with a slight delay at 60 days in GII. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Use of a Tooth-Implant Supported Bone Distractor in Oral Rehabilitation: Description of a Personalized Technique

Osteodistraction is a clinical reality available for the resolution of bone deficiencies before dental implant placement or in cases where the existing implants are at the wrong position. The objective of this study is to suggest a new possibility for bone distraction, based on tooth-implant bone distractors, in areas were there is the need for extensive alveolar bone recovery, with installed dental implants. This technique presented good results associated with its simplicity and low cost, making it a viable clinical solution for bone tissue augmentation. Although its use is recent, the suggested technique shows the potential to become used widely in attempts to achieve bone-height augmentation, primarily when dental implants are installed and osteointegrated already. (C) 2008 American Association of Oral and Maxillofacial Surgeons

Laser ablation in titanium implants followed by biomimetic hydroxyapatite coating: Histomorphometric study in rabbits

Titanium surface texture and chemistry modification successfully improves the host response and consequently the bone-to-implant contact surrounding dental implants. The aim of the present study was to investigate, using histomorphometrical-analysis, the effects of titanium surface modification by laser-ablation (Nd:YAG) followed by thin chemical deposition of HA. Forty-eight rabbits received one implant by tibiae of AS-machined (MS), laser-modified (LMS), or biomimetic hydroxyapatite-coated (HA) surface. Bone-to-implant contact (BIC) and bone area (BBT) were evaluated after 4, 8, and 12 weeks, at cortical and cancellous regions. Average BIC in the cortical region was higher (P < 0.001) on the LMS and HA implants for all periods, with no differences between LMS and HA. For the cancellous area, the LMS and HA implants showed higher (P < 0.01) BIC than MS at the initial periods. The LMS and HA showed similar values in the cortical region, but a tendency of higher values for HA in the cancellous region was observed in all periods. For the BBT, the differences were found only between HA and MS after 4 weeks in the cortical region (P < 0.05), and after 12 weeks in the cancellous area (P < 0.05). Our results showed that HA biomimetic coating preceded by laser treatment induced the contact osteogenesis and allowed the formation of a more stable boneimplant interface, even in earlier periods. Microsc. Res. Tech., 2012. (C) 2012 Wiley Periodicals, Inc.

Effects of low-level laser therapy (685 nm) at different doses in osteogenic cell cultures

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Characterization and in vitro evaluation of bacterial cellulose membranes functionalized with osteogenic growth peptide for bone tissue engineering

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Repair of critical-size defects with autogenous periosteum-derived cells combined with bovine anorganic apatite/collagen: an experimental study in rat calvaria

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Low-power laser irradiation improves histomorphometrical parameters and bone matrix organization during tibia wound healing in rats

The influence of daily energy doses of 0.03, 0.3 and 0.9 J of He-Ne laser irradiation on the repair of surgically produced tibia damage was investigated in Wistar rats. Laser treatment was initiated 24 h after the trauma and continued daily for 7 or 14 days in two groups of nine rats (n=3 per laser dose and period). Two control groups (n=9 each) with injured tibiae were used. The course of healing was monitored using morphometrical analysis of the trabecular area. The organization of collagen fibers in the bone matrix and the histology of the tissue were evaluated using Picrosirius-polarization method and Masson's trichrome. After 7 days, there was a significant increase in the area of neoformed trabeculae in tibiae irradiated with 0.3 and 0.9 J compared to the controls. At a daily dose of 0.9 J (15 min of irradiation per day) the 7-day group showed a significant increase in trabecular bone growth compared to the 14-day group. However, the laser irradiation at the daily dose of 0.3 J produced no significant decrease in the trabecular area of the 14-day group compared to the 7-day group, but there was significant increase in the trabecular area of the 15-day controls compared to the 8-day controls. Irradiation increased the number of hypertrophic osteoclasts compared to non-irradiated injured tibiae (controls) on days 8 and 15. The Picrosirius-polarization method revealed bands of parallel collagen fibers (parallel-fibered bone) at the repair site of 14-day-irradiated tibiae, regardless of the dose. This organization improved when compared to 7-day-irradiated tibiae and control tibiae. These results show that low-level laser therapy stimulated the growth of the trabecular area and the concomitant invasion of osteoclasts during the first week, and hastened the organization of matrix collagen (parallel alignment of the fibers) in a second phase not seen in control, non-irradiated tibiae at the same period. The active osteoclasts that invaded the regenerating site were probably responsible for the decrease in trabecular area by the fourteenth day of irradiation. (C) 2003 Elsevier B.V. All rights reserved.

Motor perseveration during an A not B task in children with intellectual disabilities

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Calcitonin in bone-guided regeneration of mandibles in ovariectomized rats: densitometric, histologic and histomorphometric analysis

The aim of the present study was to investigate bone promotion in surgical defects created in the mandible of normal and ovariectomized female rats using calcitonin associated with a polytetrafluoroethylene barrier. The 100 female rats were divided into four groups: control (C), control treated with calcitonin (CM), ovariectomized control (OV) and ovariectomized treated with calcitonin (OVM). A circumscribed bone defect 4 mm in diameter was created in the region of the mandibular angle, and covered with the barrier. Groups CM and OVM received 2 IU/kg of synthetic salmon calcitonin intramuscularly three times a week. The animals were killed 3, 7, 14, 21 and 28 days after surgery. The bone defects were submitted to densitometric, histologic and histomorphometric analysis. Groups C and CM showed higher levels of bone formation after 7 days compared to the OV and OVM groups. A significant difference was observed between groups C and OV at 3-14 days. The OV group presented slower bone regeneration of the surgical bone defect created in the mandibular angle than group C. Synthetic salmon calcitonin accelerated regeneration of the bone defect in the mandibles of OVM animals similarly to group C, and also increased the formation of new bone during the regeneration process in CM.

Immunolocalization of bone morphogenetic protein 2 during the early healing events after guided bone regeneration

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alongamento simultâneo do rádio e ulna em cães pelo método de Ilizarov

Com o objetivo de avaliar a funcionalidade de uma montagem do aparelho de Ilizarov para o alongamento simultâneo do rádio e da ulna, foram utilizados 15 cães, sem raça definida, adultos, com peso entre 17 e 27kg. Aplicado um fixador composto de dois anéis e quatro hastes telescópicas, realizaram-se osteotomia subperiosteal diafisária distal do rádio e ulna e distração óssea, iniciada no sexto dia de pós-operatório. Os animais foram divididos em cinco grupos formados cada um por três cães, submetidos às seguintes condutas: A- oito dias de alongamento, B- 15 dias de alongamento, C- 22 dias de alongamento, D- 28 dias de alongamento e oito dias de fase neutra com o fixador e E- 28 dias de alongamento, 60 dias de fase neutra com fixador e 45 dias sem fixador. No período de distração os animais desenvolveram gradual e progressiva contratura em flexão da articulação antebraquiocárpica, que persistiu no grupo E após a remoção do fixador. Conclui-se que no alongamento do antebraço há tendência para o desenvolvimento de contratura, recomendando-se medidas preventivas e fisioterapia.