Dentoword : Today's Word is 'Dentin'

 Welcome to Dentoword:
Learn your dental terms with detailed explanation 

Today's word is " Dentin" 

Dentin:'The Backbone of Our Teeth'

Definition : Dentin is the hard tissue that forms the bulk of a tooth beneath the enamel.

Composition of Dentin :

• Dentin consists of 65% inorganic & 35% organic material.
• The organic component is primarily composed of type I collagen fibers, which are embedded in a ground substance made up of mucopolysaccharides.
• The inorganic component consists of plate-shaped hydroxyapatite crystals.

Structure of Dentin :

• Dentin is made up of dentinal tubules . 
• The dentinal tubules house the protoplasmic extensions of the odontoblasts, known as odontoblastic processes. 
• These tubules typically follow a double-curved path, with the primary curvature forming an "S" shape. 
• The initial convexity of this curve points towards the apex.

Function of Dentin :

1. Support : 

Dentin supports the enamel & absorbs the forces of mastication,protecting the tooth from damage.

2. Sensory : 

Dentinal tubules play a key role  in tooth sensitivity. It also provides a pathway for nerves to transmit sensation such as pain & temperature to brain.

3. Repair : 

Dentin has the ability to form new dentin layers in response to injury or decay.

Properties of Dentin : 

1. Hardness :

Dentin is somewhat harder than bone but not as hard as enamel.

2. Elasticity :

Dentin possesses an elastic property crucial for tooth functionality. Its collagen content imparts this elasticity, enabling it to endure the forces of mastication.

3. Hypersensitivity : 
When dentin is stimulated by any agent, it results in a pain-like sensation known as hypersensitivity.

Development of Dentin :

Dentinogenesis is the process of dentin formation. Dentin is produced by odontoblasts, which differentiate from the ectomesenchymal cells of the dental papilla.

Types of Dentin :

1. Primary dentin (PD): 

Formed before tooth eruption.

a. Mantle dentin : 

Formed along dentinoenamel junction & seen in crown only.

b. Circumpulpal dentin : All other dentin Formed before tooth eruption. 

2. Secondary dentin(SD) : 

It is formed after tooth eruption without any external stimuli. It has a regular arrangement.

3.  Tertiary dentin(TD) : 

It is formed after tooth eruption due to external stimuli . It has an irregular arrangement and appearance.

a. Reparative dentin : 

Formed to protect pulp. Irregularity of dentin varies with duration and intensity of stimuli.

b. Sclerotic dentin : 

Dentinal tubules get blocked due to calcium salts deposition. It is formed to protect pulp and also seen as age changes.

Potential problems faced by dentin :

1. Dentinal caries

2. Tooth Erosion 

3. Dentinal hypersensitivity 

Interesting facts : 

• Unlike enamel , dentin continues to form throughout a person's life.

Conclusion :

Keeping dentin healthy is vital for overall dental well-being.Practice good oral hygiene, maintain a balanced diet, visit your dentist regularly, and use fluoride products to protect and strengthen your teeth. By taking these steps, you can ensure your dentin remains strong and your smile stays healthy.

References:

1. Orban's Oral Histology & embryology , 15th edition , G S Kumar,Elsevier.

2. Ten Cate's Oral Histology,   9th edition,Antonio Nanci, Elsevier.