ABSTRACT
INTRODUCTION: In the present study, the stability and biocompatibility of a 30 percent polymethylmethacrylate (PMMA) filling material implanted in the masseter muscle of rats were investigated according to the cytologic characteristics presented in the graft versus host reaction. METHODS: The study included 20 rats, which were divided into 4 groups: groups I, II, III, and IV corresponded to animals evaluated 7, 14, 45, and 60 days after surgery, respectively. The implant was placed in the right masseter muscle at the level of the mandibular angle. RESULTS: After 7 days, lymphoplasmacytic inflammatory infiltrates, a fibrous capsule, a large number of neutrophils, macrophages, and exudate were observed. The second group (14 days) showed granulation tissue composed of a lymphoplasmacytic inflammatory infiltrate, newly formed vessels, and a fibrous capsule. However, the second group also exhibited regeneration of the muscle fibers, and a decreased number of neutrophils and exudate. After 45 and 60 days, the inflammatory infiltrate decreased in intensity compared to the first 2 groups. CONCLUSIONS: The inflammatory reaction caused by PMMA is transient and does not compromise the function and the shape of the masseter muscle tissue, suggesting that PMMA is biocompatible.
INTRODUÇÃO: Este trabalho busca avaliar, em ratos, a estabilidade e a biocompatibilidade de um material de preenchimento à base de polimetilmetacrilato (PMMA) a 30 por cento implantado no músculo masseter, por meio do padrão, e a organização reacional no tecido receptor. MÉTODO: Foram utilizados 20 ratos, divididos em quatro grupos: grupo I, que correspondeu ao período de 7 dias de pós-operatório; grupo II, de 14 dias; grupo III, de 45 dias; e grupo IV, de 60 dias. O implante foi realizado no músculo masseter direito, na região do ângulo da mandíbula. RESULTADOS: No período de 7 dias, observou-se presença de infiltrado inflamatório linfoplasmocitário, com formação de cápsula fibrosa e presença de grande número de neutrófilos, macrófagos e formação de exsudatos. Em 14 dias, observou-se a formação de um tecido de granulação composto por infiltrado inflamatório linfoplasmocitário, vasos de neoformação e cápsula fibrosa. Porém, nesse tempo experimental, nota-se a regeneração das fibras musculares e a diminuição do número de neutrófilos e exsudatos. Após 45 dias e 60 dias, observou-se, no tecido muscular, diminuição da intensidade do infiltrado inflamatório, comparativamente aos tempos experimentais anteriores. CONCLUSÕES: A reação inflamatória provocada pelo PMMA é transitória e não compromete as funções e o contorno desse tecido muscular, o que sugere que o PMMA é biocompatível.
Subject(s)
Animals , Rats , History, 21st Century , Rats , Biocompatible Materials , Dental Implants , Muscle Fibers, Skeletal , Polymethyl Methacrylate , Inflammation , Mandible , Masseter Muscle , Neutrophils , Rats/anatomy & histology , Rats/immunology , Biocompatible Materials/analysis , Biocompatible Materials/adverse effects , Dental Implants/adverse effects , Dental Implants/veterinary , Muscle Fibers, Skeletal/pathology , Polymethyl Methacrylate/analysis , Polymethyl Methacrylate/therapeutic use , Inflammation/veterinary , Mandible/immunology , Masseter Muscle/anatomy & histology , Masseter Muscle/immunology , Neutrophils/pathologyABSTRACT
Los implantes dentales han evolucionado de forma sustancial en los últimos 40 años; sin embargo, dudas sobre las características de la reparación ósea continúan toda vez que nuevos diseños y nuevos métodos quirúrgicos son aplicados. El objetivo de esta investigación es evidenciar la presencia de tejido mineralizado en diferentes regiones del implante. Se elaboró un estudio basado en un modelo de restauración inmediata, aplicado en la mandíbula de 7 canes machos. Se realizaron las exodontias de los premolares mandibulares y, después de 3 meses de recuperación, se instalaron 2 implantes endóseos bilaterales, siendo uno de tipo cónico y otro de tipo cilíndrico. Después de dos periodos de sacrificio se realizo una evaluación histomorfométrica en los cortes seleccionados. Los resultados se presentan de forma porcentual estableciendo comparaciones entre las áreas cervical, media y apical. Los implantes de morfología cónica sometidos al modelo de restauración inmediata, presentaron mayor formación ósea en todos los niveles evaluados. En todas las condiciones de trabajo el área cervical presentó mayor presencia de tejido mineralizado que el área apical. Concluimos que el modelo de restauración inmediata no es un obstáculo para la instalación de la secuencia apropiada de reparación ósea y que diferentes factores deben estar asociados a la mayor formación ósea presente en el área cervical de los implantes dentales.
Dental implants have evolved of substantial form in the last 40 years; however, doubt about osseous repair characteristic are maintained because new design and surgical method are applied. The aim of this research is show the mineralized tissue in different areas of the implant. Was done a study based to a immediate load model applied in 7 male dogs mandible. Was realized the dental extractions of de bilateral mandibles bicusp and after to 3 month of recuperations was installed two bilaterally implants, been conical and cylindered shape. After of two sacrifices period was realized a histomorphometric analysis in the selection cut. The results are present with perceptual form, establishing cervical, meddle and apical comparison. Conical implants with immediate restoration model were present more osseous formations in all evaluated level. For all conditions of work, cervical area presented more mineralized tissue than apical area. We conclude that immediately restoration model it is not an obstacle for the installation of the appropriate sequence for the osseous reparation and that different factors have been associated to the more osseous formation in the cervical area of the dental implants.