Biomaterial Database

Ultrastructural changes in tension zones of rat molar periodontium incident to orthodontic tooth movement. 1976

P Rygh

The purpose of this study was, by introducing transmission electron microscopy, to clarify fine details of tissue reactions in the periodontal ligament on the tension side. A preliminary investigation was undertaken on nine rats in which experimental tooth movement lasted 2 days, 14 days, and 28 days. It was hoped that these new observations might help in the planning and directing of further studies. A marked increase of interstitial spaces between the formed ligament structures of the periodontal ligament was characteristic of the initial phases of tension. The cells and the endoplasmic reticulum within the cells were spindle shaped and oriented in the direction of strain. Occasionally, collagen fibrils were observed within the cytoplasm of fibroblasts. During experimental tension a higher prevalence of elastic fibers was observed and new details of the reaction of collagen fibrils were obtained. The new cementum and bone deposited during the experiment were studied. The preliminary study indicated that electron microscopy may become a valuable tool for the study of the tension side.

UI	MeSH Term	Description	Entries
D008963	Molar	The most posterior teeth on either side of the jaw, totaling eight in the deciduous dentition (2 on each side, upper and lower), and usually 12 in the permanent dentition (three on each side, upper and lower). They are grinding teeth, having large crowns and broad chewing surfaces. (Jablonski, Dictionary of Dentistry, 1992, p821)	Molars
D010513	Periodontal Ligament	The fibrous CONNECTIVE TISSUE surrounding the TOOTH ROOT, separating it from and attaching it to the alveolar bone (ALVEOLAR PROCESS).	Alveolodental Ligament,Alveolodental Membrane,Gomphosis,Alveolodental Ligaments,Alveolodental Membranes,Gomphoses,Ligament, Alveolodental,Ligament, Periodontal,Membrane, Alveolodental,Periodontal Ligaments
D003238	Connective Tissue	Tissue that supports and binds other tissues. It consists of CONNECTIVE TISSUE CELLS embedded in a large amount of EXTRACELLULAR MATRIX.	Connective Tissues,Tissue, Connective,Tissues, Connective
D003593	Cytoplasm	The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)	Protoplasm,Cytoplasms,Protoplasms
D003739	Dental Cementum	The bonelike rigid connective tissue covering the root of a tooth from the cementoenamel junction to the apex and lining the apex of the root canal, also assisting in tooth support by serving as attachment structures for the periodontal ligament. (Jablonski, Dictionary of Dentistry, 1992)	Cementoblasts,Cementum,Cementoblast,Cementum, Dental
D004547	Elastic Tissue	Connective tissue comprised chiefly of elastic fibers. Elastic fibers have two components: ELASTIN and MICROFIBRILS.	Elastic Fibers,Elastic Fiber,Elastic Tissues,Fiber, Elastic,Fibers, Elastic,Tissue, Elastic,Tissues, Elastic
D004721	Endoplasmic Reticulum	A system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)	Ergastoplasm,Reticulum, Endoplasmic
D000539	Alveolar Process	The thickest and spongiest part of the maxilla and mandible hollowed out into deep cavities for the teeth.	Alveolar Ridge,Alveolar Processes,Process, Alveolar,Processes, Alveolar,Ridge, Alveolar
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013314	Stress, Mechanical	A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.	Mechanical Stress,Mechanical Stresses,Stresses, Mechanical