Asunto(s)
Coronas , Aleaciones Dentales , Preparación de la Cavidad Dental , Porcelana Dental , Diseño de Dentadura , HumanosRESUMEN
Communications 1 to 5 will deal with the significance of the masticatory muscles as a local factor affecting the shaping of the skull. The reports are based on experiments with dogs (Beagles) on which unilateral partial resection of the mandible was performed at different ages. The animals were slaughtered one year after the operation. 1st Bulletin: More or less severe scoliosis was observed in all skulls and proved to be the principal secondary change. The deviation was found to be particularly great in the region of the viscerocranium in all cases. Other findings include a flattening of the zygomatic arch and the linea temporalis on the operated side, close spacing of the front teeth, and deformation and reduction in size of the temporomandibular joint socket.
Asunto(s)
Mandíbula/patología , Traumatismos Mandibulares/patología , Cráneo/anatomía & histología , Envejecimiento , Animales , Desarrollo Óseo , Perros , Lateralidad Funcional , Cráneo/crecimiento & desarrollo , Cráneo/patologíaRESUMEN
The measurement of the 2 halves of the skull were compared to permit quantification of the skull scoliosis and its dependency on age at the operation. It was found that the differences between the left and right sides at palate level decrease as the age at operation increases. There are no significant differences between the sides at palate level if the operation is performed at an age of 38 weeks. No distinct differences were observed between the sides in the zygomatic arch region at any age. No significant differences could be observed between the left and right sides of the neurocranium.
Asunto(s)
Desarrollo Óseo , Mandíbula/patología , Traumatismos Mandibulares/patología , Cráneo/crecimiento & desarrollo , Envejecimiento , Animales , Perros , Lateralidad Funcional , Mandíbula/cirugía , Cráneo/patologíaRESUMEN
Distinct morphological changes were found one year after partial unilateral mandibular resection. The stump left after resection was smaller in all dimensions than the corresponding part of the intact half of the mandible, and the coronoid process inclined further posteriorwards as age increased. The temporomandibular joints were atrophized in all and arthrotically deformed in some cases. The intact halves of the mandibles presented a more or less S-shaped curvature in all cases. No dependence could be found between these changes and post-surgical age.
Asunto(s)
Mandíbula/cirugía , Complicaciones Posoperatorias/patología , Animales , Perros , Mandíbula/patología , Cóndilo Mandibular/patología , Desarrollo Maxilofacial , Músculo Temporal/patología , Articulación Temporomandibular/patologíaRESUMEN
The unilateral dysbalance induced artificially in the mandibles of Beagles yields information regarding the action of the masticatory musculature as a local factor affecting craniofacial growth. Time is an important factor, particularly the age and maturity of the animals at the time of the operation and the length of the post-surgical interval prior to the measurements being taken. The time factor and differences between chewing types provide some explanation for the lack of uniformity and, sometimes, the contradictory nature of the available information regarding the secondary changes to the skull following the elimination of masticatory muscles in experimental animals. The cranial scoliosis observed as a result of mandibular dysbalance suggests strongly that the viscerocranium responds plastically to functional influences. The neurocranium, in contrast, whose shape is governed largely by the brain, is to great extent immune to such postnatal manipulations. The fact that growth of the residual mandibular stump is retarded shows that the condylar cartilage is not a primary growth centre. Postnatal mandibular growth is mainly periosteal and governed by functional stimuli. Any attempt to apply these results obtained with animal models to man must naturally take the differences between the structures of the maxillo-mandibular apparatuses into account.
Asunto(s)
Huesos Faciales/crecimiento & desarrollo , Mandíbula/anomalías , Músculos Masticadores/anomalías , Cráneo/crecimiento & desarrollo , Factores de Edad , Animales , Perros , Huesos Faciales/anomalías , Mandíbula/crecimiento & desarrollo , Masticación , Cráneo/anomalías , Factores de TiempoRESUMEN
The areas obtained by planimetry of parafrontal sections showed distinct asymmetry in the region of the cavitas nasi in the Beagles that had been operated. Although differences between the sides were also observed in the skulls of the control Beagles, they were very slight. There were no differences between the left and right sides in regard of the areas of the cavitas cerebri in either the operated or the control Beagles. In the operated skulls they are slightly larger than normal, but in the control animals they are within the physiological range of variation.