Downloaded 35 times
More Related Content
Similar to DENTIN (The facts and mysteries)
DENTIN (The facts and mysteries)
- 1. 1 Dr. Manoranjan Mahakur 1styear MDS Department of Pedodontics & Preventive Dentistry
- 2. 2 DENTIN content ata glimpse…… Interglobular Dentin Granular layer Sensation of dentin Porosity of dentin Changes of dentin History of Dentin ! What is dentin ? Attitude of dentin Backbone of dentin HOEHL CELL Sibling of dentin METADENTIN Conglomerate line
- 3. 3 HISTORY of DENTIN theunrevealed……. 1678- A.V Leeuwenhoek 1771- John Hunter “The Natural History of Human Teeth” “ Madder feeding experiment on pig ’’ 1838- Sir john Tomes – Dentinal tubules Richard Owen- Dentin (odontography-1840-45) Nasmyth- Ivory.
- 4. 4 what is DENTIN?? The fact Dentin (/ˈdɛntᵻn/) (American English) or dentine (/ˈdɛnˌtiːn/ or /ˌdɛnˈtiːn/) (British English) (Latin: substantia eburnea) is a calcified tissue of the body Dentine: ivory, tooth bone, zahnsubstanz, substantia dentis
- 5. 5 Dentin Organic (65-70)% Collagen 82% type 1 Typeiii & v Non collagenous 18% (i)DSPP(DPP,DSP) (ii)Enzyme (v)Lipid (iii)TGF,FGF,IGF-s, BMP-s In organic (20-25)% (i)Ca10(PO4)6 (OH)2 (ii)Salt of (CO3,So4,Po4 (iii)Trace elemernt (Cu,fe,Zn.F) H2O (10-15)% C O M P O S I T I O N
- 6.
- 7. 7 Physical & Mechanicalproperties of DENTIN the attitude…….. THICKNESS-3-10 mm MODULOUS OF ELASTICITY- 15-20GPA HARDNESS-68KHN CARIOUS DENTIN- 25KHN SCLEROTIC DENTIN - 80KHN COMPRESSIVE STRENGTH- 266MPa TENSILE ETRENGTH-50 MPa RADIOOPACITY – 1
- 8. 8 STRUCTURE of DENTIN thearchitec ….. Odontoblast process Dentinal tubules Non mineralized matrix ( predentin) • Minerlized matrix ( peritubular, inter tubular, inter globular)
- 9. 9 DENTINAL TUBULES(DT) the pathway…… Sigmoid shape Thickness 3-10 mm Outer surface dentin /inner surface dentin= 5/1 Diameter :pulpal > outer (4 micro mt> 1 micro mt) Nos of tubules pulpal/outer per unit are=4/1 Lateral branches called canaliculi or micro tubules
- 10.
- 11.
- 12. 12 Types of DENTIN……. thesibling ! PRIMARY DENTIN SECONDARY DENTIN TERTIARY DENTIN
- 13. 13 PRIMARY DENTIN….. Forms mostof tooth Laid down before completion of apical foramen Contains straight tubules Outlines pulp chamber = circumpulpal dentin Outer layer = mantle dentin
- 14. 14 SECONDARY DENTIN….. Develops aftercompleted root formation Laid down as continuation of primary Tubular structure (less regular than primary) Change of tubules direction at the transition from primary to secondary dentin Slower rate of matrix deposition Uneven deposition: more on roof and floor of pulp chamber - leads to reduction of pulp space (PULP RECESSION)
- 15. 15 TERTIARY DENTIN….. Produced inresponse to irritation or damage to the overlying dentin and/or enamel by cells directly affected by stimulus May be reactive or reparative dentin Reactive dentin = produced by pre-existing Odontoblast Reparative = produced by newly-differentiaed- Odontoblast like cells Irregularly arranged tubules Fewer dentinal tubules or no tubules with aging or severe damage, it can totally obliterate the pulp cavity
- 16. 16 Types of DENTINcont….
- 17. 17 PREDENTIN….. the softest Always adjacent topulp tissue 2-6 µm wide Not mineralized Collagen and proteoglycans secreted Produced Metadentin
- 18. 18 MANTLE DENTIN… the firstform Below DEJ Cushioning , 20µm Von kroff’s fiber Type III Less mineralised Few curved and thin tubules Unaffected in X linked hypophosphatemia.
- 19. 19 CIRCUMPULPAL DENTIN… the main Bulkof tooth All dentin before root compltion More mineralized Small dm collagen 4mm per day Enlarged in rickets
- 20. 20 PERITUBULAR DENTIN….. the covering Dentin immediately surrounded the dentinal tubules / Intratubular dentin Lamina limitans organic linning of calcified tubules Periodontoblastic space-between odontoblastic process and peritubular dentin Dentinal fluid – flow out ward Higher k+ and lower Na+ Missing in rodents incisor No collagen Peritubal dentin
- 21. 21 INTERTUBULAR DENTIN…… the middleman Main body of dentin Located between zone of peritubular dentin Type I collagen 3 layer model Inter tubular
- 22. 22 INTERGLOBULAR DENTIN… Mineralizationof dentin in small globules Fall to coalesce Zone of hypomineralization Seen in crown Below mantel dentin Dentinal tubule pass through it.
- 23. 23 GRANULAR LAYER ofDENTIN …… tomes granular layer Due to coalescing & looping of terminal Tubules Seen in root, adjacent to cementum More toward apex Unmineralized (like interglobular dentin)
- 24. 24 Interglobular dentin VsTomes granular layer Seen in root Calcium ++++ Phosphorus +++ Seen in crown Sulfur ++++
- 25. 25 Hyaline layer ofHopewell-Smith Most peripheral layer of initially unmineralized dentin. It is 0.5-0.8 µm thick and contains enamel matrix-like protein as well as the proteins of dentin. Initial fibers of the periodontal ligament embed Aids cementum in binding to the dentin. CEMENTUM HYALINE LAYER TOMES GRANULAR LAYER DENTIN
- 26. 26 ODONTOBLAST……. the founder Firstappear at 17-18 week in utero Cell bodies Length 40µm dm 7 µm Process DM at pulp 3- 4µm narrower to 1 µm). Matrix formation 10-4 µm per day Secretion of type I collagen,proteoglycans Enamel spindle Lateral branch
- 27.
- 28. 28 sequence of dentinformation… Coronal dentin formed before root dentine. 1st Cuspal then cervical last apical. Dentin first is formed at DEJ = the oldest dentin. Pulpal-surface dentin formed last = newest dentin.
- 29. 29 Incremental lines ofDENTIN….. the sequential Daily rhythmic deposition of dentin Fine or striatation in dentin Right angle to dentinal tubules (8 µm in crown3-4 µm in root/day) Distance between incremental line 4-8µm.
- 30. 30 INCREMENTAL LINE OFDENTIN VON EBNER OWEN NEO NATAL •Daily rhythmic deposition of dentin •Accentuated incremental line due disturbance in the matrix and mineralization •Prenatal and post natal dentin are separated by an accentuated line •Dentin form prior to birth is better
- 31. 31 Innervations of DENTIN thesensation Intratubular nerve 30-70% of odontoblastic process Both myelinated and unmylinated More near tip pulp horn In erupting teeth it remain in pulp A & C fiber Subnucleus caudalis
- 32. 32 Permeability of DENTIN… Highly permeable More towards pulp Transdentinal Intradentinal Thickness permeablity Tubular occlusion ,smear layer permeablity
- 33. 33 changes of DENTIN… Attrition,abrasion,erosion,cavity preparation Loss of Odontoblastic process Dentinal tubules filled with gaseous and liquid Reparative dentin seal dentinal tubules DARK- TRANSMITTED LIGHT WHITE – REFLECTED LIGHT
- 34. 34 changes of DENTIN… Attrition,abrasion,erosion,cavity preparation Collagen fibers & apatite crystal appear Dentinal tubules filled with crystal and obliterated DARK REFLECTED LIGHT WHITE TRANSMITTED LIGHT
- 35. 35 changes of DENTIN… Transmittedlight Reflected light
- 36. 36 ANIMALS DENTIN… the mysteries Ivory of elephant Herbivorous have alternate ridge of enamel and dentin Dermal denticle of shark Osteodentin in rodents & reparative dentin - human Vasodentin- some fish
- 37. 37 PREDENTIN 1- PRIMARY 2-SECONDARY 3- TERTIARY 1-MANTLE 2-CIRCUMPULPAL 1-PERITUBULAR 2-INTERTUBULAR 1- INTERGLOBULAR 2-TOMES GRANULAR LAYER DENTIN ODONTOBLAST HOEHLS 1-VON EBNER 2-OWEN 3-NEO NATAL 1-DEAD TRACT 2-SCLEROTIC DENTIN SUMMARY
- 38.
- 39. 39 Reference……. Orban’s Oralhistology and Embryology Ten cate’s oral histology Shafer’s Text book of oral pathology Peritubular Dentin Formation: Crystal Organization and the Macromolecular Constituents in Human Teeth☆ (JOURNAL OF STRUCTURAL BIOLOGY) www.ncbi.nlm.nih.gov/pmc/articles/PMC3 360947 •Cohen, Stephen, and Kenneth M. Hargreaves, eds. Pathways of the Pulp. 9th ed. St. Louis, MO: Mosby Elsevier, 2006. Print. •Jump up^ Nanci, Antonio. Ten Cate's Oral Histology: Development, Structure, and Function. 7th ed. • https://en.wikipedia.org/wiki/X- linked_hypophosphatemia
- 40. 40 “I will respectthe hard-won scientific gains of those physicians in whose steps I walk, and gladly share such knowledge as is mine with those who are to follow”. (Hippocratic Oath) Upcoming Seminar ……….. Dentinogenesis & Clinical consideration.