Plasma rico em plaquetas, medula óssea ou quitosana nas osteossínteses minimamente invasivas na tíbia de cães

Pós-graduação em Cirurgia Veterinária - FCAV

Sub-crestal positioning of implants results in higher bony crest resorption: an experimental study in dogs

To compare peri-implant soft- and hard-tissue integration at implants installed juxta- or sub-crestally. Furthermore, differences in the hard and soft peri-implant tissue dimensions at sites prepared with drills or sonic instruments were to be evaluated. Three months after tooth extraction in six dogs, recipient sites were prepared in both sides of the mandible using conventional drills or a sonic device (Sonosurgery(®) ). Two implants with a 1.7-mm high-polished neck were installed, one with the rough/smooth surface interface placed at the level of the buccal bony crest (control) and the second placed 1.3 mm deeper (test). After 8 weeks of non-submerged healing, biopsies were harvested and ground sections prepared for histological evaluation. The buccal distances between the abutment/fixture junction (AF) and the most coronal level of osseointegration (B) were 1.6 ± 0.6 and 2.4 ± 0.4 mm; between AF and the top of the bony crest (C), they were 1.4 ± 0.4 and 2.2 ± 0.2 mm at the test and control sites, respectively. The top of the peri-implant mucosa (PM) was located more coronally at the test (1.2 ± 0.6 mm) compared to the control sites (0.6 ± 0.5 mm). However, when the original position of the bony crest was taken into account, a higher bone loss and a more apical position of the peri-implant mucosa resulted at the test sites. The placement of implants into a sub-crestal location resulted in a higher vertical buccal bone resorption and a more apical position of the peri-implant mucosa in relation to the level of the bony crest at implant installation. Moreover, peri-implant hard-tissue dimensions were similar at sites prepared with either drills or Sonosurgery(®) .

The role of nicotine, cotinine and caffeine on the electrochemical behavior and bacterial colonization to cp-Ti

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

Exercício resistido no tratamento e prevenção de osteopenia de ratos machos jovens

Pós-graduação em Ciência Animal - FMVA

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.

Aspectos radiográficos e densitométricos de fraturas experimentais do radio de cães tratadas com plasma rico em plaquetas

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

A proporção de plasma rico em plaquetas/enxerto ósseo autógeno pode influenciar o reparo ósseo de defeito de tamanho crítico: estudo radiográfico em calvária de ratos

Introduction: It has been suggested that bone grafts combined with platelet rich plasma (PRP) present greater density than bone grafts without PRP after healing process. However, this result may depend on proportion PRP/autogenous bone (AB) graft used. Objective: The purpose of this study was to analyze radiographically the influence of the proportion PRP/particulate autogenous bone (AB) graft on bone healing in surgically created criticalsize defects (CSD) in rat calvaria. Material and method: 50 rats were divided into 5 groups: C, AB, AB/PRP-50, AB/PRP-100 and AB/PRP-150. A 5 mm diameter CSD was created in the calvarium of each animal. In Group C the defect was filled by blood clot only. In Group AB the defect was filled with 0.01 mL of AB graft. In groups AB/ RP-50, AB/PRP-100 and AB/PRP-150 the defects were filled with 0.01 mL of AB graft combined with 50, 100 and 150 µL of PRP, respectively. All animals were euthanized at 30 days post-operative. Standardized radiographic images of the rat calvaria were obtained using Digora System (Soredex, Finland). The images were evaluated by three examiners using scores that indicated the percentage of radiopacity of the defect. The obtained data were subjected to statistical analysis (Kruskal-Wallis test, p < 0.05). Result: Group C presented radiopacity significantly lower than groups AB, AB/PRP-50, AB/PRP-100 and AB/PRP-150. Group AB/PRP-50 showed radiopacity significantly greater than groups AB/PRP-100 and AB. Conclusion: It can be concluded that the proportion PRP/AB graft influences bone healing in CSD in rat calvaria.

Efeito do estresse crônico e benzodiazepínicos no reparo ósseo: estudo histológico em ratos

Stress is an environmental factor that may predispose individuals to depression. Benzodiazepines have been prescribed as effective drugs in these situations. The purpose of this study was histological evaluate of the effect of chronic stress and benzodiazepine drugs on bone healing. Bone cavities were created in both tibias of 40 male rats were divided into two groups: Control and Treaty. In this, the stressor stimulus was applied 40 days pre-operative and all post-operative days until sacrifice in the morning for 2 hours, by immobilizing restraint. These animals also received diazepam benzodiazepine group, daily, at a concentration of 5mg/Kg/peso body within 15 days of preoperative. In groups of five animals were sacrificed at 7, 14, 30 and 60 days post-surgery. At 7 days postoperatively, while the control group exhibited tissue rich in fibroblasts, the treated group showed newly formed tissue with few fibroblasts and capillaries along with lymphocytes and macrophages. At 14 days postsurgery, the control group showed newly formed trabecular bone while the treated group progressed to thin trabecular bone with numerous osteoblasts on their borders. At 30 days post-operative bone healing is complete in both groups. At 60 days post-operative characteristics observed in the treated and control groups are similar to the previous period, but with more advanced osteogenesis.

Effect of smoking on the survival of dental implants

Background. Although the long-term success of implant treatment has been well- established, failures can still occur and the smoking habit has been reported as a risk factor for implant loss. A literature review on the effects of smoking on the survival of dental implants was undertaken. Methods and Results. Medline database was used to carry out the review with the keywords “osseointegration”, “smoking” and “bone healing”. The cigarette has more than 4,000 bioactive chemical components with potential toxic effects to human tissues including bone. Nicotine is the main component of the cigarette and it is frequently associated with bone healing failures. Since smoking negatively affects the osseointegration of dental implants, the main target is to quit the consumption of cigarettes. Conclusion. Nevertheless, the smoking habit should not be an absolute contraindication for implant treatment, but, patients should be advised that they are at a greater risk of implant failure.

A oclusão nas próteses totais implantossuportadas mediatas e imediatas

Rehabilitation of edentulous patients has been a challenge for professionals since the primary concepts and fundaments of occlusal rehabilitation. However, this philosophy has been improved by implant-supported fixed dentures that represent a predictable clinical modality on modern dentistry. Nevertheless, considering that the traditional protocol requires a long period for bone healing and definitive rehabilitation, immediate loading of implants has been advantageous for functional and esthetic rehabilitation of patients in a reduced period. The aim of this study is to discuss the biomechanical and functional fundaments of occlusion for implant-supported fixed dentures with mediate and immediate loading to provide clinical evidences for longevity of this treat ment modality based on the current literature. According to this, some prerequisites as proper bone quality, excellent primary stability, sufficient number of implants, rigid splinting, and control and mastering of biomechanical fundamentals of static and dynamic occlusion are mandatory for treatment predictability and longevity.

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

Processo FAPESP: 2012/24545-3

Efeito do ácido tranexâmico associado à cola de fibrina sobre o reparo ósseo: estudo histológico em ratos

The bone repair process is controlled by complex molecular mechanisms that involve systemic and local factors. Fibrin glue is derived from human plasma and mimics the final pathway of coagulation network. Tranexamic acid inhibits fibrinolysis and prevents or decreases the formation of degradation products of fibrin and fibrinogen. The purpose of this study was to evaluate histologically in rats the effect of tranexamic acid associated with the fibrin glue on bone healing. The experiment used 60 (n = 5) male rats in: GI: Control, GII: fibrin glue, GIII tranexamic acid and GIV /fibrin glue/tranexamic acid. Bone defect (2.5mm diameter) was created in right tibia. The animals were euthanized at 7,14 and 30 days postoperatively, and the pieces were processed with hematoxylin and eosin. The results showed at 7 days post-operative surgical cavity filled with dense connective tissue rich in fibroblasts, permeated by delicate neoformed bone trabeculae in percentage of 70-80% for GI, GII and GIII and GIV to 94.8%. At 14 days post-operative newly formed bone was found between 75-85% for GI, GII and GIII and percentage above 95% for GIV. At 30 days postoperative GI and GIV showed 95-100% of mature bone tissue; GII and GIII in percentage close to 80-90%. Based on the results and methodology is concluded that fibrin / tranexamic acid glue association has positive action on bone repair.

Root reconstructed with mineral trioxide aggregate and guided tissue regeneration in apical surgery: a 5-year follow-up

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

Influence of hypertension on oral infections and endodontic treatment

Hypertension is characterized by peripheral vascular resistancethat leads to blood pressure increase and severalsystemic changes that may negatively influence one s oralhealth. Thus, the aim of this study was to conduct a literaturereview on the influence of hypertension over oral conditionsand endodontic treatment. Hypertension mainly affects theblood vessels, brain and kidneys. A hypertensive conditioncan lead to increased levels of parathyroid hormones, abnormalvitamin D metabolism, reduction in the concentrationof ionized calcium and decreased calcium absorption.Therefore, hypertension can be closely associated with oralproblems such as periodontal diseases, implant loss, difficultyin bone healing, reduced salivary flow and protein concentrationin saliva, increased number of neutrophils and, as a consequence,favoring of inflammatory processes. It has alsobeen suggested that the success rate of endodontic treatmentin hypertensive patients is lower than in normotensiveones. The response of hypertensive patients to root canaltreatment, intracanal medications and sealers should be furtherstudied in order to provide knowledge on the changes,failures and success of endodontic treatment.

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.