RCAAP Repository

Purpose: Removable Partial Dentures (RPD) still are prosthetic solution for several patients, especially for the preservation of tooth structure, reversibility and low cost. However, mandibular Kennedy Class I patients have worse prognosis of this apparatus.Thus, this study aimed to compare qualitatively through the experimental two-dimensional Finite Element Analysis (FEA), the stress distribution in the abutment tooth of conventional Free End Removable Partial Dentures (FERPD) and those associated with different types of dental implants with metallic crown. Materials and Methods: For this analysis, four hemi mandibles models with 1stand 2nd pre molar were obtained: Model A, control with conventional FERPD; Model B with RPD associated with external hexagonal implant; Model C with RPD associated with Morse taper implant; and Model D with RPD associated with short implant. With the aid of the Finite Element program Marc Mentat, the models were loaded with vertical forces of 10N on each cusp tip, totalizing 60N per model. Results: Model A exhibited the worst stress distribution on the abutment teeth. A reduction of stress on abutment teeth was observed in all models with RPD associated with implants, independently of the implant type. Conclusion: The distal placement of an implant to modify the patient s arch classification has been an alternative to improve the internal pattern of stress, in order to reduce the short comings of this type of prosthesis. Thus, this treatment indication could reduce costs for patients.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The aim of the present study was to investigate the local effect of 10% doxycycline and 1% alendronate combined with poly(lactic-co-glycolic acid (PLGA) on bone repair. Thirty rats were divided into three groups, as follow: Control Group (CG), Drug Group (DG) and Vehicle-PLGA Group (VG). Bone defect was created in the right femur and filled with: blood clot (CG); PLGA gel, 10% doxycycline and 1% alendronate (DG); or vehicle-PLGA (VG). The animals were euthanized seven or fifteen days after surgery. Bone radiodensity, bone matrix and number of osteoclasts were quantified. At seven days, the findings showed increased density in DG (177.75 ± 76.5) compared with CG (80.37 ± 27.4), but no difference compared with VG (147.1 ± 41.5); no statistical difference in bone neoformation CG (25.6 ± 4.8), VG (27.8 ± 4) and DG (18.9 ± 7.8); and decrease osteoclasts in DG (4.6 ± 1.9) compared with CG (26.7 ± 7.4) and VG (17.3 ± 2.7). At fifteen days, DG (405.1 ± 63.1) presented higher density than CG (213.2 ± 60.9) and VG (283.4 ± 85.8); there was a significant increase in bone neoformation in DG (31.5 ± 4.2) compared with CG (23 ± 4), but no difference compared with VG (25.1 ± 2.9). There was decrease number of osteoclasts in DG (20.7 ± 4.7) and VG (29.5 ± 5.4) compared with CG (40 ± 9.4). The results suggest that the 10% doxycycline combination with 1% alendronate in PLGA accelerated bone repair.

The aim of this study was to assess the effect of DLC (Diamond Like Carbon) coating of prefabricated implant screw on removal torque before and after cyclic load. The properties of DLC films, including hardness, wear resistance, chemical stability, and biocompatibility, are similar to those diamond materials. Four groups with two crowns supported by two implants (n=5) were obtained according to prosthesis Splinted and Non- Splinted with Titanium and DLC coating screw (STi, SC, NSTi e NSC). The prosthetic screws were tightened with 32Ncm, using a hexagonal wrench. The screws were retightening and the samples submitted to 106 mechanical cycles (4Hz/98N). After cyclic load, loosening torque were evaluating. The final measurements were performed and the results submitted to 3-way - Anova/Tukey’s. Negative correlation was observed between Non-Splinted prostheses and titanium screw as loosening torque of prosthetic screws, the coating screw showed better performance on both set of prostheses under cyclic load (P= 0,017). Conclusion, the DLC coating should be indicated for single crowns because it showed better performance than titanium screw.

The basal cell adenoma (BCA) is a rare benign tumor of the salivary glands that primarily affects the parotid salivary gland. The causes and mechanisms involved in its pathogenesis are poorly understood. Researches have shown nuclear accumulation of β-Catenin in BCA. β-Catenin is related to the Wnt signaling pathway, but recent studies were not able to show activation of this pathway in BCA, suggesting that the its nuclear accumulation is not related to the presence of the Wnt pathway. The Hedgeghog (HH) signaling pathway has many interfaces with Wnt pathway, including ability to translocate β-Catenin to the nucleus and therefore activate cellular proliferation and it is known that excessive HH signaling pathway can lead to cancer and metastasis, but immunohistochemistry detection of proteins in this pathway was not yet studied in BCA. The aim of this study was to investigate the presence of proteins related to HH pathway in BCA, to improve the knowledge, the pathogenesis about this lesion and if it could relate to the nuclear accumulation of β-catenin. In 21 cases of BCA, by immunohistochemistry using streptavidin-biotin-peroxidase technique, we studied the proteins Shh, the main activator of the HH pathway, Gli-1, which is related to HH signal transduction, and also Fgf-2, an important inhibitor of cell proliferation induced by Shh in neuronal precursors and tumor cells, but in normal skin Fgf-2 showed an inductor role of Shh and β-catenin. Each reaction was analyzed qualitatively and quantitatively by QuickScore Index (QI). We found weak cytoplasmic reactivity in 71.4% of the cases to Shh, and 52.4% to Gli-1. Fgf-2 was observed varied cytoplasmic and nuclear staining in 100% of the cases. For all antigens, staining was similar in both luminal and abluminal cells. The average QI were 1.7, 1.6 and 8.5 to Shh, Gli-1 and Fgf-2, respectively. There was a positive correlation only between Shh and Fgf-2. Suggesting the existence of a positive feedback in which Fgf-2 has an inhibitory effect over Shh, showing a similar action to that found in neuronal precursors and tumor cells. These results do not confirm activation of the HH pathway in BCA, and is not related with the nuclear accumulation of β-catenin. But suggest that Fgf-2 has a tumor inducing action and also could represent the explanation of typical β-catenin found in this lesion.

Hyperbaric oxygen (HBO) treatment consists in the inhalation of pure oxygen under pressure, which has been used for improve the repair of damaged tissues as well as in the prevention or treatment of tissue necrosis. This therapy has shown positive effects on bone healing with increased osteogenesis and angiogenesis. This study aimed to evaluate the effect of HBO on bone healing through the evaluation of histological (qualitative) and morphometric (bone formation and mast cell count) parameters. Fourty rats were distributed into four groups with 5 animals each (control and HBO). Bone defects were created and the animals in the experimental group were subjected to HBO sessions (90minutos under 2.5 ATA pressure). After 1, 3, 5 and 7 days the animals were euthanized, femurs were removed, processed and analyzed histologically. HBO reduced the amount of mast cells only in the period of 3 days. There was a significant difference in the percentage of bone matrix between the control group and HBO within 5 days. In general, hyperbaric oxygenation fastened the resolution of inflammation and bone repair within one week.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Clinicians nowadays have multiple options to choose the material and technic to obtain all-ceramic crown restorations. It is still important to consider the results of clinical studies for CAD/CAM restoration, determining the best option to obtain better clinical results. Restorations made by using computer-aided design and computer-aided manufacturing (CAD/CAM) systems have become popular nowadays. However, it is still important to understand, through clinical studies, the longevity and the problems related to several materials used to obtain these restorations. The purpose of this clinical study was to evaluate the survival rate of restorations obtained by CAD/CAM system in a private practice and to report the influence of material, luting cement and dental substrate used. All patients were treated with CAD/CAM restorations in a private practice clinic. Data from December 2011 to December 2013 were included, after an institutional review board approved protocol. Ninety-two patients were retrospective evaluated, consisting in 35 implant crowns and 162 dental ceramic crowns. The restorations were mostly considered accepted, without any clinical intervention. Within the limitations of this study, the CAD/CAM system produced all-ceramic restorations, with excellent clinical results, considering color, marginal adaptation, occlusion and contour. It was not possible to relate the substrate, filling material and cement in survival crowns made with CADCAM system.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

The main difference of a healthy tooth for endodontically treated tooth is the quantity and quality of the radicular dentine. The rehab of endodontically treated tooth is normally used intraradicular posts of various materials. The objective of this study is to evaluate the biomechanical behavior of e incisor endodontically treated through stress analysis, varying the type of intra-radicular retainer front impact test. A two-dimensional model was generated from a model of a bovine maxillary central incisor endodontically treated and from a intact incisor(II). A non-linear dynamic analysis is used to simulate the impact test, where a rigid object model had achieve a velocity of 1 m/s -1. The image generated show the sites with accumulation and dissipation of tensions on three levels: Teeth restored with cast post an core (CPC), teeth restored with glass fiber post (GFP) and otherwise intact incisor (II). The biomechanical behavior of endodontically treated teeth were analyzed by analysis of concentration and distribution of strain and stress (Von Misses and modified von Misses).The CPC had shown more stress inside the root than GFP. The strain on dentin were higher on CPC model than GFP model, although the strain in the post were bigger at the GFP. None of the models had similar values to the II. It is important to analyze what is the susceptibility of the patient to suffer a frontal impact before making the choice of intraradicular post for the rehabilitation of anterior teeth.

The aim of this study was to evaluate the influence of different post in a strain behavior of endodontically treated teeth on impact test. Forty bovine incisor roots with 15 mm in length were selected, treated endodontically and included in resin cylinders with simulated periodontal ligaments. The roots were randomly divided into two groups (n = 20) according to the type of post to be restored: Cast post and core (Cpc) and Glass fiber post (Gfp). Once restored, the roots were stored under constant refrigeration and then the coronal portion of post were molded for making crowns made of Ni-Cr alloy. Strain gauges were attached at the bucal surface of the root portion and subjected to the impact test. A pendulum device similar to the conventional Charpy impact test was used, it were performed using two different angles: 90 º and 45º (n = 10) at the center of the buccal crown. The strain was calculated and data were analyzed with 2-way ANOVA (α = 0.05). The results showed no statistically significant difference (P = 0.151) used to post (Cpc and Gfp). There was not a statistically significant difference (P = 0.268) for the types of angles used in the study (90º and 45º). There was not a statistically significant interaction between post and use the angle of the impact test (P = 0.478). In conclusion, there was no substantial difference in peak strains among the different post and impact angles.

The Sinonasal tract malignancies, especially those originated in the maxillary sinuses, are a group of relatively rare injuries, but extremely important principally because of the aggressiveness of its development. These injuries represent approximately 0.2 to 0.8% of all malignant tumors, and 3% of cancers of the head and neck region. The squamous cell carcinoma is distinguished as the most common malignancy in this region. In Brazilian literature, there are no studies describing the epidemiologic data of the squamous cell carcinoma of the maxillary sinuses. A preliminary survey of records the National Cancer Institute of Rio de Janeiro showed that, in the period of 10 years (1997-2006), a sample of 220 cases of cancer involving the maxillary sinus were identified, a very significant number compared to those found in the international literature. The present study is a clinical-pathological study of squamous cell carcinomas with the epicenter in the maxillary sinus, seeking to identify the main socio-demographic of patients, data from the clinical presentation of tumors, progression, treatments performed, and the complications observed. All cases of cancer located in the nasal cavity and paranasal sinuses, diagnosed and / or treated in the Section of Head and Neck Surgery of the National Cancer Institute (INCA) - Ministry of Health, located in Rio de Janeiro in the period 1997 to 2006 (ten years), were investigated retrospectively, allowing a minimum of 2 years of follow up. The sample was selected for this study considering malignancies originating in the maxillary sinus measured by the identification of the epicenter of growth and the histopathological diagnosis of squamous cell carcinoma and its variants: verrucous carcinoma, basaloid squamous cell carcinoma, papillary squamous cell carcinoma, Spindle cell carcinoma, squamous cell carcinoma and adenosquamous carcinoma. This study showed that the CCESM with its variants make up 41.5% of tumors of the maxillary sinus, this lesion is the most common of the epithelial tumors and of all tumors originated in the maxillary sinuses. The CCESM often are diagnosed clinically in advanced decades, unilateral, affecting mainly men, leucoderms, between 5th and 7th decades of life with symptoms expressed generally on the face, mouth and nose, reflected by increased volume, pain, nasal obstruction and epistaxis. Also, It was observed that the major therapeutic modalities were surgery combined with radiotherapy, radiotherapy alone, followed by surgery. The main type of complications observed was residual disease (38.8%) and there was a high rate of deaths, which increased from 2 years (79.3%) to 10 years (100.0%), with an overall rate of 84.5%.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais