Avaliação Histológica e histomorfométrica do reparo ósseo em tíbias osteotomizadas de ratos (rattus novergicus albinus), submetidos a tratamento com ultrassom, frente à presença e ausência de carga

The response of bone metabolism is directly related to hormonal factors and mechanical stimuli that the bone is exposed. The ultrasonic energy on bone healing have been shown to be crucial for the stimulation and improvement in quality of newly formed tissue. The aim of this study was to analyze the action of low intensity ultrasound on bone healing of tibial osteotomy in rats subjected to tail suspension, through histological analysis and histomorphometry. Eighteen Rattus norvegicus albinos, Wistar, adults were divided into three groups, arranged as follows: G1 (n = 6), who remained free for a period of 15 days, G2 (n = 5), suspended by the tail for a period of 15 days and G3 (n = 7), suspended by the tail for a period of 36 days. In all three groups, both tibias were subjected to mono-cortical bone injury 4X2 mm in the medial region of the diaphysis, and the left limb was used as control and the right limb undergoing treatment with ultrasound (U.S.). The right tibia was treated with pulsed ultrasound at a frequency of 1.5 MHz, duty cycle 1:4, 30mW/cm2, for 12 sessions of 20 minutes each. Samples of tibia were subjected to histological analysis, blindly, with light microscopy and histomorphometric analysis by specific software Image-Pro 6.1. The average percentage of new bone formation were subjected to analysis of variance in subdivided parcels and multiple comparison test "Student-Newman-Keuls (SNK), with a significance level of 5%. The average values and standard deviations of the percentage of newly formed bone for the groups showed the least amount of bone repair G1t (13.62% ± 4.88%) - G1c (8.68% ± 4.16%) compared G2t groups (27.17% ± 11.36%) - G2c (10.10% ± 7.90%) and G3t (23.19% ± 5.61%) - G3c (15.74% ± 7 08%). However, the mean values and standard deviations of the percentage of newly formed bone repair in the tibia treated G2t and G3t were significantly higher when compared to the repair of tibia in the control group (G2c and G3c). Consequently, we conclude that ultrasound has helped to accelerate bone repair in both the presence and absence of cargo.

Regeneração óssea guiada com o uso de matriz óssea bovina desmineralizada em defeitos ósseos experimentais em cães

Background: The principles of tissue regeneration to repair alveolar bone defects are based on the fabrication of a biologic barrier with different biomaterials. Therefore, the present study aimed to investigate the guided bone regeneration (GBR) by using membrane of demineralized bovine bone matrix (DBBM) on experimental defects in tibia of dogs. Methods: Four dogs were used and after anesthesia, shaving and antisepsis, two standardized bone defects were created on the right tibia of each animal with trephine drill. In the Control Group, the defects were filled with blood coagulum, while in the Treated Group, a membrane of DBBM was used to cover the defects. After 90 days, animals were sacrificed. Results: In the Treated Group, 67.4% of new bone formation was observed and, in the Control Group, 32.6% of the bone tissue reabsorbed when compared with initial bone volume. The membrane remained intact and no inflammatory tissue was observed on membrane/ bone interface. Conclusion: It was concluded that the use of DBBM is an osteoconductive material, presents biocompatibility and may be promise option to repair bone defects.

O efeito do consumo abusivo de alvool no torque de remoção de implantes de titânio

Studies have reported that alcohol may lead to imbalance in bone formation and resorption, however, its effects on osseointegration of titanium implants continues to be an inconclusive subject. In this context, the aim of this study was to make a biomechanical evaluation of the effect of abusive alcohol consumption on the removal torque of osseointegrated titanium implants. Male Wistar rats (n=30) were divided into two experimental groups (15 each) receiving only water (Control) or 36% alcohol solution oral administration. Thirty days later, all animals were submitted to titanium implant (2.2 mm x 4 mm) placement in the right and left tibiae. The surgical alveoli were prepared with a 2 mm drill mounted in a counter-angle hand-piece (20:1 ratio, 35 Ncm torque at 1200 rpm) under abundant cooling. Five animals from each group were euthanized at 15, 30, and 60 days. Tibiae were submitted to reverse torque analysis. Data obtained were submitted to statistical analysis by the non-parametric Kruskal-Wallis and Dunn Tests (p < 0.05). Animals in the alcohol group presented lower removal torque values when compared with control group animals for all periods tested (p < 0.05). It can be concluded that abusive alcohol consumption can reduce the removal torque of titanium implants placed in rat tibiae, suggesting that alcohol may interfere in the osseointegration process of titanium implants.

O efeito do consumo abusivo de álcool no torque de remoção de implante de titânio

Studies have reported that alcohol may lead to imbalance in bone formation and resorption, however, its effects on osseointegration of titanium implants continues to be an inconclusive subject. In this context, the aim of this study was to make a biomechanical evaluation of the effect of abusive alcohol consumption on the removal torque of osseointegrated titanium implants. Male Wistar rats (n=30) were divided into two experimental groups (15 each) receiving only water (Control) or 36% alcohol solution oral administration. Thirty days later, all animals were submitted to titanium implant (2.2 mm x 4 mm) placement in the right and left tibiae. The surgical alveoli were prepared with a 2 mm drill mounted in a counter-angle hand-piece (20:1 ratio, 35 Ncm torque at 1200 rpm) under abundant cooling. Five animals from each group were euthanized at 15, 30, and 60 days. Tibiae were submitted to reverse torque analysis. Data obtained were submitted to statistical analysis by the non-parametric Kruskal-Wallis and Dunn Tests (p < 0.05). Animals in the alcohol group presented lower removal torque values when compared with control group animals for all periods tested (p < 0.05). It can be concluded that abusive alcohol consumption can reduce the removal torque of titanium implants placed in rat tibiae, suggesting that alcohol may interfere in the osseointegration process of titanium implants.

Impacto do controle glicêmico sobre as complicações associadas ao diabetes mellitus na osseointegração

The increased prevalence of diabetic individuals has become a public health problem. Diabetes Mellitus is a metabolic disorder characterized by an increase in plasma glucose levels. It impairs the physiological equilibrium in utilization of carbohydrate by tissues. The persistent hyperglycemia can produce deleterious effects on bone formation due the microvascular complication. The present paper reviews the bibliography linking the impact of glycemic control at complications associated at diabetes mellitus on osseointegration. In experimental models of diabetes it was observed a reduced level of bone-implant contact. This failure can be reduced by means of hyperglycemia control. Also, several studies point the beneficial effect of coated implant on osseointegration process. It is necessary to take special care into account for the placement of implants in diabetic patient and improve the percentages of implant survival. A rigorous control of plasma glycaemia, together with other measures, like as absence of chronic complications, good oral hygiene and regular medical follow-up has been related to rising the percentages of successful in diabetic patients.

Osseointegration of anodized implant: effect of fibrin adhesive/TEA on primary stability

Processo FAPESP: 2012/24545-3

Combined therapy with mineral trioxide aggregate, and guided tissue regeneration for a large radicular cyst: a 13-year follow-u

Biomaterials such as membrane barriers and/or bone grafts are often used to enhance periapical new bone formation. A combination of apical surgery and these biomaterials is one of the latest treatment options for avoiding tooth extraction. In case of periapical lesions, guided tissue regeneration (GTR) is attempted to improve the self-regenerative healing process by excluding undesired proliferation of the gingival connective tissue or migration of the oral epithelial cells into osseous defects. In many cases, GTR is necessary for achieving periodontal tissue healing. This report describes the healing process after surgery in a challenging case with a long-term followup. In this case report, endodontic surgery was followed by retrograde sealing with mineral trioxide aggregate (MTA) in the maxillary right central incisor and left lateral incisor. Apicectomy was performed in the maxillary left central incisor and a 1-mm filling was removed. The bone defect was filled with an anorganic bone graft and covered with a decalcified cortical osseous membrane. No intraoperative or postoperative complications were observed. After 13 years of follow-up, the patient showed no clinical signs or symptoms associated with the lesion and radiographic examination showed progressive resolution of radiolucency. In conclusion, the combination of apical surgery and regenerative techniques can successfully help the treatment of periapical lesions of endodontic origin and is suitable for the management of challenging cases

Avaliação da incorporação de enxerto osseo homogeno fresco congelado em humanos: análise histologica e imuno-histoquímica

Allogeneic, fresh-frozen bone has been used in order to replace bone autografts. However, its osteoinduction and osteoconduction properties are not well-defined in the scientific literature. This work aimed to evaluate samples of homogenous bone grafts in humans by qualitative histological and immunohistochemical analysis. For this, ten pre-selected patients underwent surgical augmentation of bone defects. The homogenous fresh frozen block bone graft was stabilized and fixed by bicortical screws. After six months, the reopening procedure was performed for installation of osseointegrated implants. At this time surgical bone graft samples were removed by means of drill trephine. The samples were fixed in 10% formalin, processed with decalcified paraffin, and stained with hematoxylin and eosin. Immunohistochemistry was performed for the expression of Caspase 3 enzyme. The slides were brought to light microscopy for qualitative histology and immunohistochemistry. The results showed non-vital bone tissue, with few areas of deposition of new bone formation on the amorphous matrix, presence of chronic inflammatory infiltrate with areas of osteomyelitis, and expressive immunolabeling of Caspase 3. Given the methods employed and the results it was concluded that the allograft fresh-frozen block is not incorporated into the recipient bed after a healing period of six months.

Avaliação microscópica da propriedade biológica e da biocompatibilidade do osso composto e do osso integral de origem bovina

The aim of this study was to evaluate the biological properties and biocompatibility of bovine non-demineralized lyophilized and composite bones implanted in tibiae bone cavities and at the subcutaneous level. Twenty-four rats were used and sacrificed 15 and 45 days later. At the subcutaneous level, after 15 days an inflammatory reaction was seen around biomaterial particles with the presence of giant cells and at 45 days fibrous connective tissue had also developed. No signs of ectopic bone formation were observed at tibiae regions; more bone neoformation was observed at the control group (15 days) with 42.8% of the outer cortex layer against 22.6% at Orthogen and 25% at GenMix groups. At 45 days, correspondent values for bone neoformation were 62.5% at control, 26% at Orthogen, and 35% at GenMix groups, respectively. It can be concluded that both materials tested were biocompatible aiming to bone neoformation by their osteoconductive properties with no ectopic formation sites observed.

Estudo comparativo de imunomarcações (OC, VEGF, TRAP) em humanos, nas cirurgia de levantamento do assoalho de seio maxilar utilizando osso autógeno e heterógeno

Pós-graduação em Odontologia - FOA

Estudo comparativo do Biogran® e Endobon® associados a implantes com defeitos periimplantares

Pós-graduação em Odontologia - FOA

Estudo comparativo do desempenho de diferentes membranas oclusivas de Látex Natural no reparo ósseo

Introduction: In dentistry, alveolar bone resorption is a limiting factor in the well being of individuals directly interfering in the stomatognathic system, causing problems in the context of overall health. Aiming to promote biological methods that can stimulate bone regeneration, several biomimetic strategies have been developed by the use of diverse materials possible to the bone matrix, culminating in the development of techniques that promote such repair. Objective: This work is a comparative study of the performance of films made with latex as occlusive membrane for Guided Bone Regeneration (GBR) procedure in three preparations: Latex preserved in ammonia, produced by Latex rubber clones IAN873 and PR255 polymerized immediately after collection and without use ammonia as a preservative. Methods: Sixty Wistar rats were randomly divided into 4 groups of 15 animals in which bone defects of critical size (8mm diameter) were made surgically in the skull. Group A was treated by GBR through the membrane latex preserved with ammonia, Group B received the membrane made of latex from IAN873, Group C, the membrane clone PR255 and group D was not treated by GBR. After a period of 7, 15 and 50 days, 5 animals from each group were euthanized, and specimens containing bone defect collected for microscopic examination (descriptive histology and histomorphometry). Results: The results showed that after 50 days there was bone formation in higher proportions in group D (p <0.05, ANOVA followed by Tukey), suggesting that further experiments should be conducted to conclude about the presence of ammonia and the influence of kind of rubber. Conclusion: GOR is a procedure proven effective in the treatment of bone defects. Therefore, further experiments should be conducted to reach a conclusion regarding the presence of ammonia in the latex composition for the manufacture of membranes, as well as the difference induced by the species of rubber.

Biocompatibility of experimental Ti-30Ta implants with compromised primary stability: effect of TEA

Purpose: Ti-Ta alloys have high potential for dental application due to a good balance between high strength and low modulus. Absence of primary anchoring may occur when dental implants are installed immediately after tooth extraction. Tranexamic acid (TEA) is used to reduce fibrin degradation and can prevent early blood clot breakdown. The aim of this study was to evaluate the biocompatibility of Ti-30Ta implants associated or not with tranexamic acid and installed with compromised primary stability. Methods and materials: Fabricated were 20 implants of titanium ASTM F67 (Grade 4) and 20 implants of Ti-30Ta alloy with dimensions of 2.1 mm × 2.8 mm Ø. They were divided (n = 10) into Group I (Ti machined), Group II (Ti machined/tranexamic acid), Group III (Ti-30Ta alloy) and Group IV (Ti-30Ta/tranexamic acid) and were implanted in tibia (defects with 2.5 mm × 3.2 mm Ø) of 40 male rats (250 g). The surgical sites were rinsed with 5% tranexamic acid solution in Groups II and IV. The animals were euthanized at 45 days postoperative. The pieces were processed in methyl methacrylate (Stevenel's blue/Alizarin red). The percentage of peri-implant tissue repair was analyzed via images obtained by an optical microscope coupled to a digital camera using Leica software and Adobe Photoshop QWin. Data were analyzed statistically with a significance level of 5%. Results: Histomorphometric results showed 97.16% of bone-implant contact for group IV, 89.78% of bone contact for group III, 70.89% for group II and 61.59% of bone contact for group I. The statistical analyses demonstrated significant differences (P < 0.05) among group I and other groups. Conclusion: The results suggest that (a) Ti-30Ta promoted an increase of bone healing and apposition around implant; (b) tranexamic acid favored the stabilization of blood clot and bone formation.

Efeito in vivo da deposição de filmes de DLC com e sem nanopartículas de prata sobre liga de titânio para utilização em próteses articulares

Pós-graduação em Biopatologia Bucal - ICT

Impacto da maturação esquelética em biomarcadores do metabolismo ósseo e na densidade mineral óssea em adolescentes brasileiros saudáveis

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