Dentin Structure and Composition
- Dentin consists of microscopic channels called dentinal tubules.
- Dentin contains odontoblast processes and dentinal fluid.
- Dentin has branching canalicular systems of different sizes.
- Dentin is composed of 70-72% inorganic materials, mainly hydroxyapatite.
- It contains 20% organic materials, primarily collagen type 1.
- Dentin also contains dentin-specific proteins and ground substance.
- Water makes up 8-10% of dentin.
- Dentin is porous and yellow-hued.

Dentin Properties and Functions
- Dentin is softer than enamel but provides support for it.
- It decays more rapidly than enamel if not properly treated.
- Dentin has a degree of permeability, which can increase pain sensation and tooth decay.
- Dentin has elastic properties, preventing enamel fracturing.
- Changes in dentinal fluid contribute to dentinal hypersensitivity.

Dentin Types
- Dentin is classified into three types: primary, secondary, and tertiary.
- Secondary dentin is formed after root formation is complete.
- Tertiary dentin develops as a result of a stimulus, such as carious attack or wear.

Dentinogenesis
- Dentinogenesis is the process of dentin formation in teeth.
- It involves the differentiation and maturation of odontoblasts, which are responsible for producing dentin.
- Dentinogenesis is regulated by various growth factors and signaling molecules.
- The mineralization of dentin occurs through the deposition of hydroxyapatite crystals.
- Dentinogenesis is essential for tooth development and repair.

Dentin Defects and Conditions
- Dentinal sclerosis is a change in the structure of teeth characterised by calcification of dentinal tubules.
- Dentinal sclerosis affects primary dentin.
- Dentinogenesis imperfecta is a genetic disorder that affects the development of dentin.
- It is characterised by the abnormal formation of dentin, resulting in weak and discolored teeth.
- Odontoblasts are specialised cells found in the pulp of teeth.
- They are responsible for the formation of dentin and the maintenance of tooth vitality.
- Tooth development begins during embryogenesis and continues throughout childhood and adolescence.
- Tooth development is regulated by a complex interplay of signaling pathways and genetic factors.
- Dentin is a mineralised tissue that forms the bulk of the tooth structure.
- The dentin substrate provides mechanical support to the tooth and helps in transmitting sensory stimuli.

Dentin (Wikipedia)

Dentin (/ˈdɛntɪn/) (American English) or dentine (/ˈdɛnˌtiːn/ or /ˌdɛnˈtiːn/) (British English) (Latin: substantia eburnea) is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by enamel on the crown and cementum on the root and surrounds the entire pulp. By volume, 45% of dentin consists of the mineral hydroxyapatite, 33% is organic material, and 22% is water. Yellow in appearance, it greatly affects the color of a tooth due to the translucency of enamel. Dentin, which is less mineralised and less brittle than enamel, is necessary for the support of enamel. Dentin rates approximately 3 on the Mohs scale of mineral hardness. There are two main characteristics which distinguish dentin from enamel: firstly, dentin forms throughout life; secondly, dentin is sensitive and can become hypersensitive to changes in temperature due to the sensory function of odontoblasts, especially when enamel recedes and dentin channels become exposed.

Dentin
Parts of a tooth, including dentin
Details
Identifiers
Latin	dentinum
MeSH	D003804
TA98	A05.1.03.055
TA2	937
FMA	55628
Anatomical terminology [edit on Wikidata]