Resumo A instalação de implantes no segmento anterior da mandíbula, é um tratamento utilizado para reabilitação de mandíbulas atróficas. Para melhorar a estabilidade primária desses implantes, a base da mandíbula pode ser usada como ancoragem complementar (bicorticalização). Este estudo objetiva analisar a biomecânica de mandíbulas atróficas, reabilitadas com prótese sobre implantes monocorticalizados ou bicorticalizados. Para isso foram confeccionados dois modelos tridimensionais de mandíbula desdentada e com atrofia severa. Em um deles foram instalados 4 implantes monocorticalizados (McMM), enquanto no segundo foram instalados 4 implantes bicorticalizados (BcMM); foi modelada uma prótese total implantossuportada sobre cada modelo e aplicada uma carga axial total de 600N, distribuída nos dentes posteriores. Os modelos foram submetidos à análise de elementos finitos. Os resultados demonstraram que as maiores tensões de compressão se concentraram na região cervical dos implantes no McMM, (-32,562Mpa); já no BcMM, as tensões de compressão foram observadas nas corticais superior e inferior da mandíbula e aumento das tensões de compressão nos implantes distais (-63,792 Mpa). Com isso, concluímos as forças de carregamento axial apresentam-se melhor distribuídas pela estrutura óssea peri-implantar, em implantes monocorticalizados. e as tensões sobre o tecido ósseo, no BcMM, ocorrem nas regiões que circundam as regiões apicais e cervicais do implante. atróficas bicorticalização. bicorticalização . (bicorticalização) severa McMM , (McMM) BcMM (BcMM) 600N N posteriores finitos 32,562Mpa 32562Mpa Mpa 32 562Mpa (-32,562Mpa) 63,792 63792 63 792 (-63,79 Mpa. Mpa) apresentamse apresentam periimplantar, periimplantar peri implantar, implantar peri-implantar ósseo implante (bicorticalização (McMM (BcMM 3 (-32,562Mpa 63,79 6379 6 79 (-63,7 63,7 637 7 (-63, 63, (-63 (-6 (- (

Abstract Rehabilitation of edentulous atrophic mandibles involves the placement of implants in the anterior segment of the mandible. The primary stability of these implants can be improved using the base of the mandible as complementary anchorage (bicorticalization). This study aimed to analyze the biomechanics of atrophic mandibles rehabilitated with monocortical or bicortical implants. Two three-dimensional virtual models of edentulous mandibles with severe atrophy were prepared. Four monocortical implants were placed in one model (McMM), and four bicortical implants were placed in the other (BcMM). An implant-supported total prosthesis was prepared for each model. Then, a total axial load of 600 N was applied to the posterior teeth, and its effects on the models were analyzed using finite element analysis. The highest compressive stresses were concentrated in the cervical region of the implants in the McMM (-32.562 Mpa); in the BcMM, compressive stresses were distributed in the upper and lower cortex of the mandible, with increased compressive stresses at the distal implants (-63.792 Mpa). Thus, we conclude that axial loading forces are more uniformly distributed in the peri-implant bone when using monocortical implants and concentrated in the apical and cervical regions of the peri-implant bone when using bicortical implants. bicorticalization. bicorticalization . (bicorticalization) threedimensional three dimensional McMM, , (McMM) BcMM. BcMM (BcMM) implantsupported implant supported Then 60 teeth analysis 32.562 32562 32 562 (-32.56 Mpa Mpa) 63.792 63792 63 792 (-63.79 Mpa. Thus periimplant peri (bicorticalization (McMM (BcMM 6 32.56 3256 3 56 (-32.5 63.79 6379 79 (-63.7 32.5 325 5 (-32. 63.7 637 7 (-63. 32. (-32 63. (-63 (-3 (-6 (- (

With the aim of helping in the diagnosis and treatment of the lesions that affect the muscles enervate for masseteric nerve, as well as to offer anatomical information of great importance for the accomplishment of surgeries in the infratemporal area we have done this study. It has the objective to determinate the length and the penetration point of the masseteric nerve, in the masseter muscles. Twenty hemiheads were used, fastened in formol, of adult individuals of both sexes and different breed. Initially, it was made the dissection of the pieces by an endocranian access, once located the nerves, we passed to the mensuration of the same ones, using as proximal reference the oval foramen and as distal reference the penetration point of the nerve in the muscle. For the determination of the penetration point we used the zygomatic arch as reference. The penetration points were projected to the surface with the aid of a pin, and compared with the references already described giving thus, subsidies for an eventual approach of those structures for the surface. The obtained results were analyzed in a statistics, where we could conclude that there are no significant differences in the length among the right and left sides. We ended although the medium length of the masseteric nerve is of 45,26mm, and that the masseteric nerves penetrate in the superior third of the masseter muscle

El conocimiento anatómico de la región infratemporal es importante desde el punto de vista anátomo-quirúrgico. Por tal motivo y con el objetivo de ayudar en el diagnóstico y tratamiento de las lesiones que afectan al músculo masetero, determinamos la longitud y el punto de penetración del nervio masetérico en el músculo masetero. Utilizamos 20 hemi-cabezas formolizadas, de individuos adultos, de ambos sexos y diferentes grupos étnicos. Inicialmente se efectuó la disección de las piezas anatómicas por vía endocraniana, donde se localizaron los nervios masetéricos de ambos lados. Éstos fueron medidos usando como punto de referencia proximal el foramen oval y como referencia distal la penetración del nervio en el músculo, relacionándose esta última referencia con el arco cigomático. Los puntos de penetración se proyectaron a la superficie con la ayuda de un alfiler y se relacionaron con las estructuras anatómicas. La longitud promedio del nervio masetérico fue de 45,26mm, no existiendo diferencias estadísticamente significativas entre los lados izquierdo y derecho. El nervio penetra en el tercio superior del músculo masetero

The aim of this study is to determinate the length and the penetration point of the deep temporal nerves, in the temporal muscles. Twenty hemiheads were used, fastened in formaldehyde, of adult individuals of both sexes and of different ethnic groups. Initially, it was made the dissection of the pieces by an endocranian access, once located the nerves, we passed to the measurement of the same ones, using as reference the oval foramen and the penetration point of the nerve in the muscle. For the determination of the penetration point it was used two pre-certain lines that delimited the area of penetration of the deep temporal nerves in the temporal muscle. The first, is a line that tangency the zigomatic arch, and the second, is a line parallel to the one that tangency the supra orbital margin. The penetration points were projected to the surface with the aid of a pin, and compared with the references already described giving, subsidies for an eventual approach of those structures for the surface. The results obtained were analyzed in a statistics, where we could conclude that there are no significant differences in the length among the right and left sides. Althought we could conclude that the medium length of anterior deep temporal nerve is 27,26mm; of the medium deep temporal nerve is of 26,02mm; and of the posterior deep temporal is of 24,93mm. We could conclude too that in most of cases the deep temporal nerves penetrates in the inferior third of the temporal muscle.

El objetivo de este estudio fue determinar la longitud y el punto de penetración de los nervios temporales profundos, en los músculos temporales. Se usaron 20 hemi-cabezas formolizadas, de individuos adultos de ambos sexos y de diferentes grupos étnicos. La disección se efectuó por vía endocraneana y una vez localizados los nervios temporales, fueron medidos usando como referencia el foramen oval y el punto de penetración del nervio en el músculo temporal. Para la determinación del punto de penetración se usaron dos líneas que delimitaban el área de penetración de los nervios temporales profundos en el músculo temporal. Los puntos de penetración se proyectaron a la superficie. Los resultados obtenidos fueron analizados estadísticamente, no encontrándose diferencias significativas entre ambos lados. La longitud promedio de los nervios temporales profundos fue: anterior 27,26mm; medio 26,02mm; posterior 24,93mm. Concluimos que en la mayoría de los casos los nervios temporales profundos penetran en el tercio inferior del músculo temporal.