Dental Tissues

Question 1

What is the anatomical crown?

Answer 1

It is the part of the tooth covered by hard tissue called enamel.

Question 2

What is the clinical crown?

Answer 2

It is the visible teeth that can be seen in the patients mouth

Question 3

What is the root?

Answer 3

The root is the part of tooth covered by a hard tissue called cementum.

Question 4

What is the Cervical Margin?

Answer 4

The cervical margin is the margin between the crown and the root, it is informally known as the neck of the tooth.

Question 5

What is the incisal edge?

Answer 5

It is the cutting edge of the front teeth,

Question 6

What is the occlusal Surface?

Answer 6

It is the bite/grinding of back teeth.

Question 7

What is the apex?

Answer 7

The apex is the end of the root, nerves and blood supply enter through the apex.

Question 8

What is the difference between the anatomical crown and the clinical crown?

Answer 8

The anatomical crown remains constant.
The clinical crown varies as it relies on the gumline, gingival recession/erupting teeth can result in more visible clinical crown.

Question 9

What is underneath the enamel?

Answer 9

Underneath the enamel is the Amelodentinal Junction, followed by Dentine then Pulp.

Question 10

What surrounds the outer exterior of the lower dentine below the cervical margin?

Answer 10

Cementum surrounds the outer exterior of the lower dentine below the cervical margin.

Question 11

What are the ideal properties of tooth?

Answer 11

Strong
Hard
Wear Resistant
Resistant to Chemical Damage
Ability to respond to damage
Ability to repair
Aesthetic

Question 12

What does the enamel enable the tooth?

Answer 12

The enamel enables the tooth to be strong, hard and wear resistant. It is a mineralized tissue.

Question 13

What part of the tooth is Vital, what part of the tooth isnt?

Answer 13

Dentine and pulp is vital, enamel is not.

Question 14

What does the term vital mean?

Answer 14

The term vital means that the part of the tooth can respond to damage and repair itself.

Question 15

What makes up each hard dental tissue?

Answer 15

Each hard dental tissue has different levels of composition regarding their Mineral, Matrix and Water content.

Question 16

What does high mineral content result in?

Answer 16

High Mineral Content results in a brittle and easy to break dental tissue.

Question 17

What does Lower Mineral Content + Higher Organic Material result in?

Answer 17

Lower Mineral Content + Higher Organic Material means more shock/stress absorbent/ flexible meaning it can prevent fracturing of more harder, higher mineralised tissues.

Question 18

What are some key points about Enamel?

Answer 18

Covers anatomical crown
Epithelial Product = Epithelial in origin
96% inorganic – made up of hydroxyapatite
2mm thickness at maximum
Translucent
Non-Vital
Hard
Brittle – Easy to fracture
Main Structural Feature, Enamel Prism
Unit of Enamel is Prism

Question 19

What is necessary regarding the enamel bur?

Answer 19

Enamel Bur (drill) needs to be able to cut through enamel, hencewise it consists of a high-speed air turbine made up of diamond and tungsten carbide.

Question 20

How can unsupported enamel be easily fractured?

Answer 20

Un-supported enamel is easily fractured with a hand instrument e.g. chisel

Question 21

What are some key points about Dentine?

Answer 21

Specialised Connective Tissue
Hard (KHN 75)
Strong and Resilient
70% mineral - consisting of hydroxyapatite
20% organic - collagen
Tubular meaning it is a porous structure
It is continuous with the pulp - around 15k to 65k tubules per mm2
These tubules may contain cell processes, nerves or fluid which flow out from them.
They are vital.
This means they can repair itself
Unit of Dentine is Dentinal Tubules

Question 22

What is Dentine made up of?

Answer 22

Dentine is made up of Collagen Fibres

Question 23

What are the different burs that can be used for dentine?

Answer 23

Depending on the Dentine, different burs can be used.

Question 24

What kind of burs can be used for sound dentine?

Answer 24

2 options -

Diamond burs (high speed)

Bladed burs (Low/high speed)

Question 25

What burs can be used for Carious Dentine?

Answer 25

Carious Dentine is soft, as such it is best to be cut with bladed bur or hand excavator as it is soft/ if close to pulp

Question 26

How is dentine growth pre-eruption?

Answer 26

Pre-eruption, dentine forms quickly

Question 27

What happens to the rate of dentine growth as the age of person increases?

Answer 27

As age of person increases, Dentine Growth decreases

Question 28

Is tubule density and character consistent in every site/location in dentine?

Answer 28

Depending on the site/location in dentine, there are variations in tubule density and character.

Question 28

What do the cells of dentine line up against?

Answer 28

Cells of dentine line up against the enamel and pulp.

Question 29

What happens to the site, the more closer it is to the bone?

Answer 29

The more closer the sight to the bone, the more porous the tubules.

Question 29

What dentine layer is closest to the pulp?

Answer 29

Predentine is the layer close to the pulp.

Question 30

What layer of dentine is close to the enamel?

Answer 30

Amelodentinal Junction is the layer close to the enamel.

Question 31

How do fillings stay in the mouth?

Answer 31

Fillings have mechanical retention

Question 32

How are fillings bonded to enamel?

Answer 32

They are bonded to enamel via: * Acid etch - "glue" * And utilises structure enamel

Question 33

How are fillings bonded to dentine?

Answer 33

They are bonded to Dentine via: * Acid demineralisation dissolves organic material to increase retention * Infiltrate collagen with resin * Penetrate Tubules with resin

Question 34

What is dental pulp?

Answer 34

* It is a specialised connective tissue * Essentially a matured Dental Papilla * Dentine is the calcified tissue of the pulp It is vital

Question 35

Is dental pulp vital?

Answer 35

Dental pulp is vital.

Question 36

What are the functions of dental pulp

Answer 36

Pulp Functions * Dentine Formation * Defence and Repair * Sensory

Question 37

What parts does the dental pulp consist of?

Answer 37

Dental pulp consists of different parts * Pulp Horns, depending on shape of teeth/number of cusps, they can have varying number of pulp horns * Pulp chamber * Accessory furcation canal = this is for teeth that have multiple roots * Lateral Canal * Root Canal * Apical Delta * Apex

Question 38

What consists of Apical Anatomy?

Answer 38

Cementum Radiographic Apex Apical Constriction Cemento-dentinal Junction Apical Foramen

Question 39

When does the tooth end?

Answer 39

The end of the teeth is at the end of the pulp.

Question 40

Why are lateral canals not very good for root canal treatments?

Answer 40

Lateral Canals arent always visible in radiographs, and can cause difficulty in root canal treatments, as the branching canals aren't always filled properly resulting in an area of infection.

Question 41

How can the nerves and blood supply be cut off?

Answer 41

The nerves and blood supply can be cut off by being squashed by the alveolar bone and apex. However, a periodontal ligament prevents this.

Question 42

How is the Dentine and Pulp linked?

Answer 42

The Dentine and Pulp is linked: Embryologically Physically Functionally

Question 43

What can happen as a result of dentine being porous?

Answer 43

Any material / procedure may irritate pulp resulting in inflammation Some materials are "therapeutic" - CA(OH)2 Calcium Hydroxide which can help generation of dentine

Question 44

What are the flaws of pulp?

Answer 44

It is effectively enclosed in a rigid chamber meaning there is no scope for tissue to swell when inflamed, meaning it cannot expand, resulting in a lot of pain if inflammed.

Question 45

What is Cementum?

Answer 45

* Mineralised Tissue * Mineralised Specialised Connective Tissue * Covers Tooth Roots * Tooth support Resistant to resorption.

Question 46

What is the Cementum-Enamel Relationship?

Answer 46

60% The Cementum will cover the Enamel 30% They will just meet the enamel 10% There will be a space between Enamel and Cementum resulting in exposure of Dentine This can cause vulnerability and sensitivity of tooth.