Avaliação da diferentes tipos de fixação interna estável em fraturas desfavoráveis de ângulo de mandibula sob análise de elementos finitos

Orientador: Prof. Dr. Nelson Luis Barbosa RebelattoDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências da Saúde, Programa de Pós-Graduação em Odontologia. Defesa: Curitiba, 2016Inclui referências : f. 29-32;38-41Resumo: A fratura de ângulo de mandíbula é uma das fraturas mais comum entre as fraturas mandibulares e em seu tratamento por fezes é utilizado placas e parafusos de titânio para fixação dos segmentos. Com o tratamento cirúrgico podem ocorrer complicações pós operatórias como infecções, a não-fixação dos fragmentos e a fratura do material de síntese. O método do elemento finito (MEF) é uma forma de análise matemática, que se baseia na divisão de uma estrutura para um número finito de pequenas áreas, chamados elementos finitos. Para esta divisão dá o nome de "malha". Em geral, o MEF tem a capacidade de matematizar estruturas e modelos, tornando-se possível aplicar forças em qualquer lugar e / ou a direção. O objetivo do estudo foi avaliar 5 tipos diferentes de fixação interna estável de mandíbula pelo MEF, avaliando forca de propagação ao osso e resistência a tensão. Para este estudo, um modelo tridimensional de uma mandíbula foi obtido a partir de uma imagem de tomografia computadorizada e uma fratura desfavorável de ângulo foi simulada. A partir deste modelo, foram avaliados cinco tipos diferentes de fixação interna estável: grupo 1, a técnica de Champy com uma miniplaca de 4-furos, sistema 2.0 mm ; grupo 2, técnica com duas miniplacas paralelas convencionais de 4 furos, sistema 2.0mm ; grupo 3, técnica com duas placas locking paralelas de 4 furos, sistema 2.0 mm; grupo 4, a técnica com uma placa reconstrução de 6 furos, sistema 2.4 mm ; grupo 5, técnica com uma miniplacas de 4 furos, sistema 2.0 mm + uma placa de reconstrução de 6 furos, sistema 2.4 mm. Os resultados mostraram que as tensões são mais bem distribuídas no sistema locking sendo que estas placas e parafusos apresentaram menor concentração de tensão, quando comparado com as placas e parafusos convencionais. A técnica de Champy apresentou os piores resultados relacionados a tensões em placas e parafusos. Há pouca diferença de resistência a tensão entre as os grupos que continham placas de reconstrução. Conclui-se, então, que a utilização do sistema locking apresenta menor resistência a tensão se comparados ao sistema não locking. Uma placa de reconstrução isolada não foi capaz de suportar a tensão sem propagação ao tecido osso como a técnica sugere. A presença de uma placa de reconstrução associada a uma miniplaca não leva á maior estabilidade se comparada com uma placa de reconstrução isolada. Palavras-Chave: Fratura Mandibular, Fixação interna Estável, método de Elementos FinitosAbstract: The mandibular angle fracture is the most common fracture among this type of injury in jaw bone and also is the type of fracture treatment that presents a larger number of complications as infections and non-fixation of the fragments. A series of treatments for this typo of fracture with different types of osteosynthesis have been studied over the years by the world literature. The finite element method (FEM) is a form of mathematical analysis, which is based on dividing a structure into a finite number of small areas, called finite elements. In this division receives the name of "mesh". In general, the FEM has the ability to mathematically model structures, making it possible to apply forces anywhere and / or direction. For this study, a three-dimensional model of a mandible was obtained from a tomographic image. One unfavorable angle fracture was simulated. From this model, five different types of fixation technique were evaluated: group 1, Champy technique with one 4-holes miniplate, 2.0 system; group 2, technique with two parallel 4-holes conventional miniplates, 2.0 system; group 3, technique with two parallel 4-holes locking miniplates, 2.0 system; group 4, technique with one reconstruction 6-holes plate, 2.4 system in base jaw; group 5, technique with one reconstruction 6-holes plates, 2.4 system in jaw body + one parallel 4- holes conventional miniplate, 2.0 system. Results: The results showed that strains are better distributed through the locking miniplate and the locking screws presented higher stress concentration when compared with the conventional ones. The Champy technique had the worst results about stresses in plates and screw. There is no significant stress difference between the groups with reconstruction plates. Conclusion: the use of the locking system shows less stress compared to the non-locking system, the presence of a reconstruction plate associated with a miniplate does not lead to increased stability compared with an isolated reconstruction plate and one reconstruction plate doesn't protected the bone tissue as the technique suggests. Keywords: Key words: finite element method, angle fracture, stable internal fixation

Surgical treatment of desmoplastic fibroma in the jaw using mandibular graft reconstruction – a case report

Introduction: Considered a rare benign tumour of fibroblastic origin, desmoplastic fibroma is an injury with aggressive behaviour and local recurrence and unclear aetiology, although trauma and genetic factors are considered. The pathology may develop in the femur, radio, pelvis and tibia, and rarely affects the jaws, characterized as an injury of slow asymptomatic growth that may vary radiographically. The local aggressive resection is the treatment of choice. Objective: To report a case of a desmoplastic fibroma in the mandible, whose treatment was en bloc resection followed by reconstruction with mandibular graft. Case report: Female patient, 33 years old, Caucasian, with a bone lesion discovered in routine x-ray. Images showed hypodense image with discrete destruction of bone cortical, near teeth 36 and 37, with no involvement of the roots. The chosen treatment was en bloc resection followed by reconstruction with mandibular graft harvest from ramus. Conclusion: desmoplastic fibroma is a benign lesion that should be included in the differential diagnosis list of osteolytic lesions. A long-term follow up is required, considering the potential to recurrence.Introduction: Considered a rare benign tumour of fibroblastic origin, desmoplastic fibroma is an injury with aggressive behaviour and local recurrence and unclear aetiology, although trauma and genetic factors are considered. The pathology may develop in the femur, radio, pelvis and tibia, and rarely affects the jaws, characterized as an injury of slow asymptomatic growth that may vary radiographically. The local aggressive resection is the treatment of choice. Objective: To report a case of a desmoplastic fibroma in the mandible, whose treatment was en bloc resection followed by reconstruction with mandibular graft. Case report: Female patient, 33 years old, Caucasian, with a bone lesion discovered in routine x-ray. Images showed hypodense image with discrete destruction of bone cortical, near teeth 36 and 37, with no involvement of the roots. The chosen treatment was en bloc resection followed by reconstruction with mandibular graft harvest from ramus. Conclusion: desmoplastic fibroma is a benign lesion that should be included in the differential diagnosis list of osteolytic lesions. A long-term follow up is required, considering the potential to recurrence

Adenomatoid hyperplasia of minor salivary glands: a report of two cases

Introduction: Adenomatoid hyperplasia of minor salivary glands is a rare benign lesion that can be mistakenly diagnosed as other types of salivary gland neoplasms. It presents as a small firm nodule or as an exophytic mass, usually painless with normal mucosa, and slightly red or blue. Histologically, aggregates of relatively normal acinar lobule mucosa can be seen in larger amounts than expected, causing increased volume and sometimes pain. Case report: This article describes two cases of adenomatoid hyperplasia of minor salivary glands, the first in the left buccal mucosa of a 12 year-old boy and the second in the labial mucosa of a 44 year-old woman, and a review of previous reports of this pathology in English literature. The clinical appearance of the tumor is indistinguishable from salivary gland neoplasms and pathological examination is therefore essential for definitive diagnosis of this pathology. In both cases the treatment chosen after diagnosis was follow up and no changes were observed over 2 years from the first appointment

Clinical assessment of oral mucositis and candidiasis compare to chemotherapic nadir in transplanted patients

Oral mucositis is a chief complication in patients undergoing hematopoietic stem cell transplantation (HSCT). It is considered a toxic inflammatory reaction that interferes with the patient’s recuperation and quality of life. Oral candidiasis is a common fungal infection observed in dental practice, particularly in immunocompromised patients. The aim of this study was to evaluate the presence of oral mucositis and oral candidiasis in patients who underwent HSCT and their correlation with the chemotherapeutic nadir (lowest possible outcome). We evaluated patients with different diagnoses who underwent HSCT at the Hospital Erasto Gaertner. No chemotherapeutic nadir curves could be associated with mucositis, and patients had different presentations of mucositis. No patient developed oral candidiasis during hospitalization. Together with cell counts, we collected demographic data including age, oral hygiene, habits harmful to health, and the use of oral prostheses. It was observed that patients who smoked cigarettes before hospitalization showed less mucositis, resulting in no feeding problems or other comorbid conditions due to the effect of mucositis. However, the nadir of the chemotherapy curve, in isolation, is not a predictive tool for the appearance (or no appearance) of oral mucositis