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)

Evaluation of periapical changes following endodontic therapy: digital subtraction technique compared with computerized morphometric analysis

Objectives: The aim of this study was to compare two methods for the evaluation of periapical lesion changes following endodontic therapy (digital subtraction technique and morphometric analysis) by outlining the radiolucent area.Methods: 13 human anterior teeth with pulp necrosis and chronic periapical lesions were used. Periapical radiographs were taken immediately after endodontic therapy (0) and then 2 months, 4 months and 6 months post treatment, using an intraoral radiographic film holder stabilized with impression material. The films were processed in a standard manner and the digitized images were submitted to digital subtraction using Adobe Photoshop 6.0. New bone formation or bone resorption areas were then measured. In the morphometric analysis, the periapical lesions were outlined using VixWin 2000 and the area (in square millimetres) was recorded. The obtained data were submitted to agreement analysis for comparison of the two techniques.Results: There was no correlation between the areas of radiographic changes detected by digital subtraction and periapical lesion outline (r=0.02-0.45). The new bone formation areas observed by digital subtraction presented higher values, with bone changes being especially evident in the 2 month follow-up radiographs, which suggests a higher sensitivity for this method.Conclusions: Both methods are suitable for the evaluation of periapical lesion changes, but the digital subtraction technique is more sensitive for detecting radiographic periapical changes. Dentomaxillofacial Radiology (2009) 38, 438-444. doi: 10.1259/dmfr/53304677

Autogenous demineralized dentin matrix for tissue engineering applications: Radiographic and histomorphometric studies

Purpose: This work evaluated the osteoconductive properties of autogenous demineralized dentin matrix (ADDM) on surgical bone defects in the parietal bone of rabbits, using the guided bone regeneration technique and polytetrafluoroethylene (PTFE) membrane. Materials and Methods: Surgical bone defects were created in 24 adult rabbits and repaired with either ADDM and PTFE (experimental group) or PTFE alone (control group). The ADDM had been obtained from the central incisors of the experimental rabbits. The rabbits were sacrificed after 15, 30, 60, and 90 days and the defects examined radiographically and histologically. Results: Radiographically, the defects in the experimental animals achieved radiopacity more quickly than the defects in the control group. Discussion: After 15, 30, 60, and 90 days of observation following surgery, the ADDM slices appeared to stimulate new bone formation. The dentin slices were completely incorporated into the new bone tissue and were resorbed during the bone repair. Conclusions: Bone repair was accelerated on the bone defects treated with ADDM when compared to the control group.

A influência da deficiência estrogênica no processo de remodelação e reparação óssea

INTRODUÇÃO: Nestes últimos anos, descobriu-se a complexidade dos mecanismos que influenciam a atividade óssea, e grande parte das pesquisas direcionou-se para o estudo de fatores capazes de modular as funções ósseas. Essa expansão da pesquisa deve-se, em parte, ao reconhecimento da osteoporose como importante problema na velhice. A osteoporose constitui uma das osteopatias mais comuns, caracterizando-se pela redução da massa óssea, determinada, por sua vez, pelo desequilíbrio entre reabsorção e neoformação. OBJETIVO: Apresentar uma revisão da literatura sobre os principais aspectos da remodelação e da reparação associados à deficiência estrogênica. Remodelação óssea: O osso apresenta processo contínuo de remodelação, entretanto anormalidades nesse processo ocorrem em algumas doenças, entre elas a osteoporose, sendo que a deficiência estrogênica parece ter o papel principal na sua gênese. Reparação óssea: Tal processo envolve uma cascata complexa de respostas biológicase, assim como a remodelação, é afetado por fatores locais e externos e regulado pela interação de diferentes mecanismos. Portanto, o aumento ou o decréscimo da capacidade de reparação óssea têm sido relacionados a alterações ocorridas na remodelação. Deficiência estrogênica e metabolismo ósseo: A maioria dos autores sugere uma redução na capacidade de remodelação e de reparação do tecido. DISCUSSÃO: Ainda não está determinado qual estágio da reparação é mais alterado, se a fase inicial de formação do calo ósseo, se a de mineralização ou se a fase tardia da reparação, a remodelação óssea. CONCLUSÃO: Como os mecanismos fisiológicos e a patogênese das alterações ósseas causadas pela deficiência estrogênica não estão completamente estabelecidos, novas pesquisas ainda são necessárias.

Morphological deformities in the osseous structure in spotted sorubim Pseudoplatystoma coruscans (agassiz & spix, 1829) with vitamin c deficiency

A vitamina C é essencial para dietas de peixe porque muitas espécies não conseguem sintetizá-la. Esta vitamina é necessária par a formação de cartilagem e matriz óssea. Além disso, age como antioxidante e melhora as resposta do sistema imunológico. O presente trabalho investigou os efeitos da suplementação de vitamina C em dietas para alevinos de pintado (Pseudoplatystoma corruscans) pela incidência de deformidades na estrutura óssea e cartilaginosa. O ascorbil polifosfato (AP) foi utilizado como fonte de vitamina C em dietas para alevinos de pintado durante o período de três meses. Seis dietas foram formuladas: uma dieta controle (0 mg de vitamina C / kg) e cinco dietas 500, 1.000, 1.500, 2.000 e 2.500 mg de AP / kg. Os peixes alimentados sem suplementação de vitamina C apresentaram deformidades óssea na cabeça e mandíbula e fragilidade de nadadeiras. Assim, a dieta de 500 mg de AP/kg foi suficiente para prevenir a ocorrência de deformidades, e a ausência desta vitamina prejudica o desenvolvimento ósseo de juvenis de pintados.

Poliuretana de mamona (Ricinus communis) para desvio da crista tibial no cão

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

Enxerto ósseo esponjoso autólogo em pequenos animais

O enxerto ósseo esponjoso autólogo é formado por osso trabecular, poroso e altamente celular. Visto ser de fundamental importância na cirurgia ortopédica de pequenos animais, o trabalho teve por objetivo discorrer sobre a função, locais de colheita, cuidados, formas de aplicação, indicações e contra-indicações desse enxerto. Ele estimula a formação óssea devido ao fornecimento de células vivas e fatores de crescimento, mas não possui suporte mecânico. A asa do ílio craniodorsal, úmero proximal, tíbia proximal e fêmur distal, são os locais de colheita mais utilizados em cães. A asa do ílio consiste no local mais satisfatório para gatos. Para maximizar a incorporação do enxerto com o tecido hospedeiro, devem ser tomados alguns cuidados entre a colheita e a transferência para a área receptora. Além disso, pode ser aplicado sem compressão dentro do local recipiente. A freqüência de complicações é considerada baixa.

In vitro biocompatibility of a novel membrane of the composite poly(vinylidene-trifluoroethylene)/barium titanate

This study was aimed at investigating the in vitro biocompatibility of a novel membrane of the composite poly(vinylidene-trifluoroethylene)/barium titanate (P(VDF-TrFE)/BT). Osteoblastic cells were obtained from human alveolar bone fragments and cultured under standard osteogenic condition until subconfluence. First passaged cells were cultured on P(VDF-TrFE)/BT and expanded polytetrafluoroethylene (e-PTFE - control) membranes in 24-well plates. Cell adhesion and spreading were evaluated at 30 min, and 4 and 24 h. For proliferation assay, cells were cultured for 1, 7, and 10 days. Cell viability was detected by trypan blue at 7 and 10 days. Total protein content and alkaline phosphatase (ALP) activity were measured at 7, 14, and 21 days. Cultures were stained with Alizarin red at 21 days, for detection of mineralized matrix. Data were compared by ANOVA and Student t test. Cell attachment (p = 0.001), cell number (p = 0.001), and ALP activity (p = 0.0001) were greater on P(VDF-TrFE)/BT. Additionally, doubling time was greater on P(VDF-TrFE)/BT (p = 0.03), indicating a decreased proliferation rate. Bone-like nodule formation took place only on P(VDF-TrFE)/BT. The present results showed that both membranes are biocompatible. However, P(VDF-TrFE)/BT presented a better in vitro biocompatibility and allowed bone-like nodule formation. Therefore, P(VDF-TrFE)/BT could be an alternative membrane to be used in guided tissue regeneration. (c) 2006 Wiley Periodicals, Inc.

Free autogenous cartilage grafts to the mandible of rats-histological study.

The present study was designed to histologically evaluate the behavior of free autogenous cartilage grafts to the mandible of rats. A 3-mm segment was removed from the last rib of male adult rats and transplanted fresh to a receptor bed prepared on the mandibular ramus. The results showed that the grafts maintained their vitality up to 120 days and the perichondrium was biologically integrated to the osseous bed. Appositional growth of the grafts was found. New bone formation was observed in close proximity to the grafts, but newly formed trabeculae did not arise from perichondrium.

Osseous regeneration in the presence of fibrin adhesive material (Tissucol) and epsilon-aminocaproic acid (EACA).

The effects of Tissucol and Tissucol/EACA on bone healing were evaluated histologically. Experimental defects were made in both tibias of 25 rats. Test materials were placed in defects in right tibias and left tibias served as control. Five animals in each group were killed at 1, 3, 7, 14 and 21 days after surgery. Results showed that: a) Tissucol did not interfere with connective and osseous tissue formation; b) Tissucol allowed new bone formation; c) Tissue residues in Tissucol groups in sections of 21-day specimens did not impair healing; d) Tissucol/EACA was usually completely resorbed and healing was complete 21 days after surgery in the Tissucol/EACA group.

Treatment of fibrinolytic alveolitis with rifamycin B diethylamide associated with gelfoam: a histological study.

The most common complication in the healing of extraction wounds is fibrinolytic alveolitis, which may also be termed dry socket. Reduction in the incidence of this condition after the application of topical antibiotics and the use of systemic antibiotics has been reported. A histological study of disturbed alveolar socket healing in rats was carried out to analyze the influence of application of rifamycin B diethylamide (Rifocin M) associated or not with Gelfoam. Sixty-four male rats (Rattus norvegicus albinus, Wistar), weighing 120-150 g, were divided into 4 groups of 16 animals each. In the second group of rats which received implants of Gelfoam, there was an intense resorption of bone walls in the initial stage. The rats that received implants of Gelfoam saturated with Rifocin M (fourth group) showed better results than the second group. The third group (only irrigation with rifamycin) showed better bone formation in the alveolar socket compared to the first, second and fourth groups. Thus, these results showed that rifamycin irrigation is useful in the control of alveolar infections.

Effects of fibrin adhesive material (Tissucol) on alveolar healing in rats under stress.

The effects of Tissucol on alveolar healing following stress were evaluated histologically, comparing three groups of 28 male albino rats each. Stress was applied and their right upper incisors were extracted. Group A served as an empty control site. In Group B, Tissucol was applied into the alveolar cavity. Group C received local antifibrinolytic treatment (alveolar irrigation with epsilon-aminocaproic acid solution) before implant of Tissucol into the tooth socket. Four animals in each group were killed at 1, 3, 6, 9, 15, 21 and 24 days after surgery. Results showed that: 1) Tissucol did not interfere with connective and osseous tissue formation; 2) Tissucol allowed new bone formation; 3) Tissucol residues in Group B in sections of 24-day specimens did not impair healing; 4) Tissucol was usually completely resorbed and healing was complete 24 days after surgery in Group C.

Persistência do forame de Huschke: Um estudo tomográfico

OBJECTIVE: To evaluate the persistency of foramen of Huschke by means of computed tomography study of the ear region and approaching important clinical aspects related to the presence of this anatomical anomaly. MATERIALS AND METHODS: Two examiners have analyzed the whole tympanic portion of temporal bone in 150 bilateral computed tomography studies of the ear region, searching for foramen of Huschke presence or absence. RESULTS: The mentioned anatomical anomaly was found in 17 cases (11.3%), 13 patients (76.5%) being female and four (23.5%) male. This higher female incidence is statistically confirmed. CONCLUSION: Ear and/or temporomandibular joint specialists should turn their attention to the persistency of foramen of Huschke.

Homeostase do cálcio e marcadores do metabolismo ósseo no hipertireoidismo felino - Revisão

Hyperthyroidism is the most frequent endocrine disease in old-aged cats. It is a illness provoked by the excess of circulating thyroid hormones. Hyperthyroidism causes alteration in bone metabolism with predominance of activity resorption. The evaluation of bone metabolism can be made by measuring serum and urinary markers of bone metabolism or bone mineral densitometry. Osteoblasts are responsible cells for bone formation while the osteoclasts are for resorption. In physiological situation osteoblastic and osteoclastic activities are in balance. Markers of bone formation express the osteoblastic activity and markers of the osseous resorption the osteoclástica activity. Markers of bone turnover are important in the diagnosis and prognostic of muscle-skeletal disease, as well as in the accompaniment of therapy. It is fundamental do carry on studies on the influence of feline hyperthyroidism on markers of bone formation and resorption in bone turnover to comprise pathophysiologic mechanism of bone alterations.

Os efeitos de um programa de atividade física de carga progressiva nas propriedades físicas e na força óssea de ratas osteopênicas

Background: Many studies have shown that physical exercises are able to stimulate bone formation and increase bone mass, constituting a therapeutic modality to treat bone loss due to osteoporosis. However, some points about the intensity, duration and frequency of the exercises remain confusing and contradictory. Thus, the aim of this study was to determine the effects of a progressive loading exercise program on femur of osteopenic rats. To induce osteopenia we used the animal model of ovariectomy (OVX). Forty animals was studied and divided into 4 groups: sham-operated sedentary (SS); ovariectomy-sedentary (OS); sham-operated training (ST) and ovariectomy training (OT). The trained groups performed jumps into water: 4 series of 10 jumps each, with an overload of 50% to 80% of the animal's body weight, during 8 weeks. Femora were submitted to a physical properties evaluation, a biomechanical test, calcium and phosphorus content measurement and a morphometric histological evaluation. Results: osteopenic animals showed a decrease of bone strength and lower values of bone weights, bone density and calcium content. The exercised osteopenic rats showed higher values of geometrical, physical properties, bone strength and calcium content compared to controls. The results of the present study indicate that the progressive loading exercise program had stimulatory effects on femora of osteopenic rats. It seems that the intensity and duration of the protocol used produced bone structural adaptations, which contributed to reverse bone loss due to ovariectomy.