Avaliação do efeito de um campo magnético permanente na cicatrização óssea em fêmures de ratos

Proposição:estudar a qualidade da cicatrização óssea sob efeito de um campo magnético permanente, sepultado, in vivo. Materiais e Método: foi criado um modelo metálico composto de duas arruelas de aço inoxidável, fixadas, cada uma, à estrutura óssea, através de parafusos de titânio comercialmente puro. Neste estudo experimental, randomizado, com grupos testes e controle, foram selecionados 24 ratos da raça Rattus novergicus albinus, cepa Wistar, divididos em cinco grupos, sendo quatro testes e um controle. Cada animal foi submetido à cirurgia para a fixação de um par de dispositivos metálicos no fêmur esquerdo, tangenciando uma cavidade cirurgicamente criada. Nos grupos testes as arruelas foram posicionadas de modo que exercessem forças de atração mútua. Os animais foram sacrificados aos 15, 30, 45 e 60 dias pós-operatórios. As peças foram submetidas à avaliação histológica. Resultados: entre os grupos de 15 e 30 dias, a cicatrização dos grupos testes mostrou-se acelerada em relação aos controles. Aos 45 dias, ambos os grupos revelaram resultados pouco divergentes entre si. Aos 60 dias, houve marcada neoformação óssea no grupo teste, propondo um efeito de estimulação magnética continuada durante todo o período experimental. Conclusão: a liga de aço inoxidável imantada, sepultada, in vivo, foi capaz de estimular e acelerar o processo de cicatrização óssea

Diagnosis accuracy using diferente high-resolution CBCT scans : vertical root fractures

As fraturas radiculares verticais (FRV), tanto em dentes vitais como tratados endodonticamente e restaurados com pinos intracanais, são de difícil diagnóstico por meio de exames radiográficos convencionais devido à sobreposição de estruturas. A tomografia computadorizada de feixe cônico (TCFC) apresenta um poder diagnóstico superior quando comparada à radiografia convencional. Dessa forma, realizou-se o presente estudo com o intuito de avaliar a capacidade diagnóstica da TCFC, com diferentes protocolos, adquiridas em três aparelhos de marcas diferentes para detecção de FRV simuladas e a interferência do artefato metálico na visualização das mesmas. Para isso, 240 imagens de dentes unirradiculares foram incluídos neste estudo, divididos em dois grupos (fraturados) grupo teste e grupo controle (não fraturados). Os dois grupos, após a endodontia, foram preparados para a colocação de pinos metálicos e pinos de fibra. Foram obtidas imagens multiplanares com o menor FOV disponível no equipamento e em dois protocolos standard e high definition. Os tomógrafos utilizados foram um Ortophos SL 3D (DensplaySirona), ORTHOPANTOMOGRAPH OP300 (KaVo), e PaX.i-3D (VATECH). As imagens tomográficas foram analisadas por três examinadores, individualmente, chegando a um consenso entre eles quando foi necessário. Os resultados obtidos das avaliações foram analisados por meio das medidas de, sensibilidade, especificidade e acurácia. O teste de qui-quadrado foi realizado para comparar o rendimento diagnóstico em imagens obtidas pelos diferentes aparelhos, protocolos e retentores intrarradiculares. Também foi realizado o índice de incerteza com 20 % da amostra. O nível de significância aceito foi de 5%. Os resultados mostram que do total de erros de diagnóstico encontrados, 41,7% ocorreram nas imagens obtidas do aparelho Pax.i3D, 36,1% do Orthophos SL3D e 22,2% do OP300. Quanto ao o protocolo utilizado padrão ou de alta definição não houve diferenças. Já quanto ao retentor intrarradicular, 61,1% dos erros foram na presença do pino metálico e, 38,9% na presença do pino de fibra. A partir desses resultados, concluímos que o tipo de equipamento e retentor intrarradicular influenciam o diagnóstico de FRV em exames de TCFC.Vertical root fractures (FRV), both in vital teeth and endodontically treated and restored with intracanal pins, are difficult to diagnose by means of conventional radiographic examinations due to overlapping structures. Cone beam computed tomography (CBCT) has a superior diagnostic power when compared to conventional radiography. Thus, the present study was carried out with the aim of evaluating the diagnostic capacity of CFFC, with different protocols, acquired in three different brands of devices for the detection of simulated FRV and the interference of the metallic artifact in their visualization. For this, 240 images of uniradicular teeth were included in this study, divided into two groups (fractured) test group and control group (non-fractured). The two groups, after endodontics, were prepared to place metallic pins and fiber pins. Multiplanar images were obtained with the lowest FOV available on the equipment and in two standard and high definition protocols. The CT scanners used were an Ortophos SL 3D (DensplaySirona), ORTHOPANTOMOGRAPH OP300 (KaVo), and PaX.i-3D (VATECH). The tomographic images were analyzed by three examiners, individually, reaching a consensus between them when necessary. The results obtained from the evaluations were analyzed using measures of, sensitivity, specificity and accuracy. The chi-square test was performed to compare the diagnostic yield in images obtained by different devices, protocols and intraradicular retainers. The uncertainty index was also performed with 20% of the sample. The level of significance accepted was 5%. The results show that of the total diagnostic errors found, 41.7% occurred in the images obtained from the Pax.i3D device, 36.1% from Orthophos SL3D and 22.2% from OP300. As for the standard or high definition protocol used, there were no differences. As for the intraradicular retainer, 61.1% of the errors were in the presence of the metallic pin and 38.9% in the presence of the fiber pin. From these results, we conclude that the type of equipment and intraradicular retainer influence the diagnosis of FRV in CBCT exams

Evaluation of bone repair using a poly(butylene adipate co-tereeftalate) (PBAT) composite associated with niobium-dopped bioglass

INTRODUÇÃO: biomateriais têm sido desenvolvidos para uso como substitutos ósseos para a recuperação funcional e estética de perdas de estrutura óssea por trauma ou patologias. Os compósitos à base de polímeros biodegradáveis têm se mostrado uma opção terapêutica promissora. OBJETIVO: avaliar o reparo ósseo, in vivo, de um compósito de poli (butileto adipato co-tereftalato) (PBAT) associado a biovidro e nióbio em fêmures de ratos (PBAT/BAGNb). METODOLOGIA: cento e quarenta ratos foram divididos em 4 grupos, sendo (1) controle negativo sem preenchimento; (2) controle positivo com osso autógeno; (3) matriz óssea bovina desmineralizada (MOBD); e, (4) compósito de PBAT/BAGNb. No fêmur de cada rato foi criado um defeito cirúrgico crítico de 2mm de diâmetro por 2mm de profundidade. Cada grupo foi preenchido com o respectivo enxerto ou substituto ósseo, com exceção do grupo controle negativo. O compósito foi fabricado como arcabouço tridimensional nas dimensões do defeito. Os tempos experimentais foram de 15, 30 e 60 dias pós-operatórios. Os fêmures foram submetidos às análises qualitativa e histomorfométrica. Os dados qualitativos foram descritos e os dados quantitativos foram tabulados e submetidos à análise estatística. RESULTADOS: na análise qualitativa, o compósito formou osso em um padrão de osteogênese ao redor do compósito; os grupos autógeno e MOBD formaram osso como descrito em estudos prévios; no grupo controle não ocorreu formação de osso no interior do defeito. Os dados quantitativos mostraram neoformação óssea em todos os grupos, com maior área de neoformação para o grupo MOBD (39,2±10,29%), seguida pelo enxerto autógeno (36,5±13,05%), pelo grupo controle (24,9±6,67%), e pelo grupo PBAT/BAGNb (12,3±5,63%). Houve diferença estatisticamente significante entre todos os grupos, com exceção dos grupos autógeno e MOBD, quando analisados entre si. CONCLUSÃO: o compósito de PBAT/BAGNb formou osso em um padrão de neoformação ao redor do arcabouço e dentro dos poros, porém, em pequena quantidade de área de neoformação óssea (12,3±5,63%) em comparação aos demais grupos estudados.INTRODUCTION: biomaterials have been developed to enhance functional and aesthetical repair due to bone loss from trauma or pathologies. Composites based on biodegradable polymers have been a promising therapeutic option. OBJECTIVE: to assess the bone repair, in vivo, with a composite of poly (butylene adipate coterephtalate) and niobium-dopped bioglasses (PBAT/BAGNb), in rat femurs. METHODOLOGY: one hundred and fourty rats were divided into 4 groups: (1) sham control without filling; (2) positive control with autogenous bone graft; (3) demineralized bovine bone matrix (MOBD); and, (4) PBAT/BAGNb composite. A surgical defect of 2mm diameter per 2 mm depth was surgically created on each femur. Each group received a bone graft or biomaterial; the sham group did not receive filling. The composite was designed and printed as a tridimensional scaffold within the shape of the surgical defect. The experimental periods were 15, 30 and 60 post-operative days. The femurs were submitted to qualitative and histomorphometric analysis. The qualitative data were described. The quantitative data were submitted to statistical analysis. RESULTS: the qualitative analysis showed a osteogenic pattern around the scaffold as well as inside its pores; the autogenous and MOBD groups showed the same neoformation as described in previous studies; in the control groups there were no complete bone formation. The quantitative data showed that bone neoformation occurred in all the groups, with the larger neoformation area for MOBD (39,2±10,29%), followed by autogenous bone graft (36,5±13,05%), controle group (24,9±6,67%), and, PBAT/BAGNb (12,3±5,63%). There were statistically significant difference among all groups, except for groups autogenous and MOBD. CONCLUSION: PBAT/BAGNb composite enhanced the bone formation in and around the scaffold, however, in small amount of newly formed bone area (12,3±5,63%) compared to the other groups

Histological analysis of the effects of a static magnetic field on bone healing process in rat femurs

Background: The aim of this study was to investigate, in vivo, the quality of bone healing under the effect of a static magnetic field, arranged inside the body. Methods: A metallic device was developed, consisting of two stainless steel washers attached to the bone structure with titanium screws. Twenty-one Wistar rats (Rattus novergicus albinus) were used in this randomized experimental study. Each experimental group had five rats, and two animals were included as control for each of the groups. A pair of metal device was attached to the left femur of each animal, lightly touching a surgically created bone cavity. In the experimental groups, washers were placed in that way that they allowed mutual attraction forces. In the control group, surgery was performed but washers, screws or instruments were not magnetized. The animals were sacrificed 15, 45 and 60 days later, and the samples were submitted to histological analysis. Results: On days 15 and 45 after the surgical procedure, bone healing was more effective in the experimental group as compared to control animals. Sixty days after the surgical procedure, marked bone neoformation was observed in the test group, suggesting the existence of continued magnetic stimulation during the experiment. Conclusion: The magnetic stainless steel device, buried in the bone, in vivo, resulted in increased efficiency of the experimental bone healing process

Histological analysis of the effects of a static magnetic field on bone healing process in rat femurs

Background: The aim of this study was to investigate, in vivo, the quality of bone healing under the effect of a static magnetic field, arranged inside the body. Methods: A metallic device was developed, consisting of two stainless steel washers attached to the bone structure with titanium screws. Twenty-one Wistar rats (Rattus novergicus albinus) were used in this randomized experimental study. Each experimental group had five rats, and two animals were included as control for each of the groups. A pair of metal device was attached to the left femur of each animal, lightly touching a surgically created bone cavity. In the experimental groups, washers were placed in that way that they allowed mutual attraction forces. In the control group, surgery was performed but washers, screws or instruments were not magnetized. The animals were sacrificed 15, 45 and 60 days later, and the samples were submitted to histological analysis. Results: On days 15 and 45 after the surgical procedure, bone healing was more effective in the experimental group as compared to control animals. Sixty days after the surgical procedure, marked bone neoformation was observed in the test group, suggesting the existence of continued magnetic stimulation during the experiment. Conclusion: The magnetic stainless steel device, buried in the bone, in vivo, resulted in increased efficiency of the experimental bone healing process

Classification of bifid mandibular canals using cone beam computed tomography

The objective of this study was to classify the morphology of bifid mandibular canals and to evaluate their relationship with the roots of third molars, using cone beam computed tomography (CBCT) scans. The CBCT scans of 75 patients were analyzed and the bifurcations were classified according to Langlais et al. (1985). The relationship of bifurcation and third molars was established according to the following classification: class A - uninvolved, class B - close relationship, class C - intimate relationship and class D - absence of third molars. Data were submitted to descriptive statistics, and the results indicated that the patients' mean age was 48.2 (± 13.2) years. Unilateral bifurcation (Type 1) was the most frequent type (72.6%), followed by unilateral Type 2 (19.3%). Class D was the most frequent (57.33%), followed by class C (21.33%), class B (13.33%) and class A (8%). It could be concluded that most cases presented unilateral bifid mandibular canals extending to the third molar or adjacent regions, and when present, the roots seemed to be a continuation of the bifid mandibular cana