Odontoclast

from Wikipedia, the free encyclopedia

An odontoclast (from ancient Greek ὀδούς odoús , German 'tooth' , and ancient Greek κλᾰστός klastós , German 'broken' ) is a type of cell that breaks down dental hard substances (mainly dentin and cement , but also tooth enamel ). The odontoclasts depending on the function in Dentinoklasten ( English dentinoclasts , Dentinfresser) and Zementoklasten divided. The process of breaking down tooth roots is known as odontoclasia . They are multinucleated giant cells. The cell membrane , which is strongly folded in the area of ​​absorption processes , acts as a proton pump and releases hydrogen ions into the adjacent tissue, which leads to acidification and the dissolution of the minerals . The release of enzymes from the lysosomes of the odontoclasts also breaks down the organic matrix of the tooth substance. Odontoclasts are particularly important for the regression of the milk tooth roots during the tooth change . In addition, they are involved in some dental diseases.

origin

During myelopoiesis, the clastic cells are formed from mononuclear precursors in the blood-forming tissue. The series of monocytes and macrophages with the multinucleated odontoclasts develop from pluripotent stem cells .

morphology

Odontoclasts are large cells with multiple nuclei . These giant cells are created through cell fusion. They are smaller and contain fewer cell nuclei than the bone-degrading osteoclasts . The cytoplasm appears vacuolated . The cell membrane is characterized by a strong fold with approx. 2 to 3 µm invaginations on the absorption surfaces. The cell plasma here contains lysosomes , which are rich in acid phosphatase , and mitochondria . There are no cell organelles in the part of the cell facing away from the absorption surface , but the cell plasma is rich in actin and myosin .

function

Odontoclasts cause the natural elimination of the roots of deciduous teeth in the dentition from baby teeth to permanent teeth in the mixed dentition. The odontoclasts can also be found in the resorption of reimplanted teeth. Tooth roots can react with an increase in the force exerted on them during orthodontic treatment with resorption of the traumatized tissue by odontoclasts. The formation of root resorptions on permanent teeth requires the loss or damage of the protective cement layer and the periodontal membrane, which is followed by the establishment of an inflammatory reaction on the "unprotected" tooth structure.

The resorptive dissolution of hard tissue takes place according to the following pattern:

Clinical significance

The Multiple idiopathic external apical root resorption (MIEARR, German  multiple idiopathic outer apical root resorption ) is a relatively rare disease of unknown etiology that affects a plurality of teeth in a denture. Because the condition is not symptomatic, it is usually recognized as an incidental radiographic finding. In severe cases, however, pain and tooth loosening can occur. Adult men are predominantly affected. There are no known preventive or curative treatments.

In feline odontoclastic resorptive lesions ( FORL ), a common and very painful disease of the teeth in cats, odontoclasts are activated by cytokines and inflammatory mediators. The affected teeth should be extracted.

The EOTRH - Equine Odontoclastic Tooth Resorption and Hypercementosis is known in horses . In this disease, inflammatory processes lead to chronic resolution of the roots of incisors , canines and horse teeth , especially in older horses.

See also

Individual evidence

  1. ↑ James K. Avery (Ed.): Oral Development and Histology , 3rd edition, Georg Thieme Verlag , Stuttgart, New York 2002, ISBN 978-1-58890-028-9 .
  2. ↑ James K. Avery, Daniel J. Chiego: Essentials of Oral Histology and Embryology , 3rd edition, Elsevier Mosby, London 2006, ISBN 978-0-3230-3339-8 .
  3. ^ Günter Thiele (Ed.): Handlexikon der Medizin , Urban & Schwarzenberg , Volume 3 (L − R), Munich, Vienna, Baltimore without year, p. 1765.
  4. ^ Roche Lexicon Medicine , 5th edition, Urban & Fischer , Munich, Jena 2003, ISBN 978-3-437-15156-9 , p. 1352.
  5. ↑ GS Kumar: Orban's Oral Histology & Embryology . Elsevier Health Sciences, 13th ed. 2014, ISBN 978-81-312-2819-7 , p. 355; 14th edition 2015, ISBN 978-81-312-4033-5 .
  6. ↑ Angela Pierce, Pathophysiological and therapeutic aspects of dentoalveolar resorption , in: Australian Dental Journal, 1989; 34 (5); Pp. 437-448.
  7. ↑ Victor E. Arana-Chavez, Vivian Bradaschia-Correa: Clastic cells: Mineralized tissue resorption in health and disease , in: International Journal of Cell Biology , March 2009, Volume 41, Issue 3/2009, pp. 446-450. doi : 10.1016 / j.biocel.2008.09.007 .
  8. ^ Maxim Zetkin , Herbert Schaldach: Lexikon der Medizin , 16th edition, Ullstein Medical, Wiesbaden 1999, ISBN 3-86126-126-X , p. 1437.
  9. ↑ Rao K. Bharath: Fundamentals of Oral Anatomy, Physiology and Histology . Elsevier Health Sciences, 2018, ISBN 978-81-312-5413-4 , p. 176.
  10. ↑ Anita Pesic, Risk Factors for Orthodontically Induced Root Resorptions , Dissertation 2008, Ludwig Maximilians University in Munich. P. 29.
  11. ↑ Dorothy Permar, Rudy C. Melfi, Keith E. Alley: Permar's Oral Embryology and Microscopic Anatomy , Lippincott Williams & Wilkins, 10th Edition, Philadelphia, London 2000, ISBN 978-0-6833-0644-6 .
  12. ↑ Gabriel Krastl, Roland Weiger, External Root Resorptions after Dislocation Injuries, Endodontie 2012; 21 (1), pp. 33–43
  13. ↑ F. Moazami, B. Karami: Multiple idiopathic apical root resorption: a case report. In: International Endodontic Journal. 40, 2007, p. 573, doi : 10.1111 / j.1365-2591.2007.01267.x .
  14. ↑ Markus Eickhoff: Dentistry, oral medicine and maxillofacial medicine for small and domestic animals . Georg Thieme Verlag, 2005, ISBN 978-3-8304-1038-6 , p. 211 ff.
  15. ^ Carsten Vogt: Textbook of dentistry in horses. Schattauer Verlag for Medicine and Natural Sciences, Stuttgart 2011, ISBN 3-7945-2690-2