11 research outputs found
Congenital Nasal Piriform Aperture Stenosis or Bony Inlet Stenosis: A Report of Three Cases
THE ULTRASTRUCTURE OF THE INTRA-ÁRTICULAR DISC OF THE TEMPOROMANDIBULAR JOINT, WITH SPECIAL REFERENCE TO FIBROCARTILAGE
Cells in the intra-articular disc of the temporomandibular joint of the rat, guinea pig, rabbit, ferret, marmoset and sheep were studied at the ultrastructural level_. The cells were generally rounded in outline and possessed moderate amounts of roughened endoplasmic reticulum and other organelles associated with protein synthesis and secretion. No intracellular collagen profiles were observed. Many of the cells possessed conspicuous amounts of microfilamentous material. Cell membranes in the rat, guinea pig, rabbit, ferret and sheep were closely applied to the collagen fibrils of the extracellular matrix. Occasionally in these animals, a narrow, irregular space containing microfilamentous material surrounded the cell membrane. Many cells in the marmoset differed from this description in being completely surrounded by an obvious pericellular matrix devoid of collagen fibrils and being comprised of microfilamentous material embedded in an amorphous ground substance. These chondrocyte-like cells in the intra-articular disc of the marmoset differed from chondrocytes in hyaline cartilage by lacking a pericellular capsule
Characterization of Murine Autologous Salivary Gland Graft Cells: A Model for Use with an Artificial Salivary Gland
Effects of inflammatory periodontal disease (‘broken mouth’) on the mobility of the sheep incisor
Apoptosis in the Connective Tissues of the Periodontal Ligament and Gingivae of Rat Incisor and Molar Teeth at Various Stages of Development
A constitutive model for the periodontal ligament as a compressible transversely isotropic visco-hyperelastic tissue
This study is devoted to the development of a non-linear anisotropic model for the human periodontal ligament (PDL). A thorough knowledge of the behaviour of the PDL is vital in understanding the mechanics of orthodontic tooth mobility, soft tissue response and proposed treatment plans. There is considerable evidence that the deformation of the PDL is the key factor determining the orthodontic tooth movement. The paper focuses on the biomechanical aspect of the behaviour of the PDL. In terms of continuous mechanics, the PDL may be treated as an anisotropic poro-visco-hyperelastic fibre-reinforced compressible material which is subject to large deformations and has an essentially non-linear behaviour. Furthermore, there are issues related to the non-linear tooth and PDL geometry. A new constitutive model for the PDL is proposed. The macroscopic continuum approach is used. The model is based on the non-linear large deformation theory, involving the Lagrangian description. The material is assumed to be compressible, visco-hyperelastic and transversely isotropic. A free-energy function is suggested that incorporates the properties. It also takes into account that the PDL behaves differently in tension and compression. The free-energy function and the associated constitutive equations involve several material parameters, which are to be evaluated from experimental strain-stress data available from the literature and the tooth movement experiments conducted by our team using novel optical motion analysis techniques