Dental Tissues Flashcards
What is the anatomical crown?
It is the part of the tooth covered by hard tissue called enamel.
What is the clinical crown?
It is the visible teeth that can be seen in the patients mouth
What is the root?
The root is the part of tooth covered by a hard tissue called cementum.
What is the Cervical Margin?
The cervical margin is the margin between the crown and the root, it is informally known as the neck of the tooth.
What is the incisal edge?
It is the cutting edge of the front teeth,
What is the occlusal Surface?
It is the bite/grinding of back teeth.
What is the apex?
The apex is the end of the root, nerves and blood supply enter through the apex.
What is the difference between the anatomical crown and the clinical crown?
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.
What is underneath the enamel?
Underneath the enamel is the Amelodentinal Junction, followed by Dentine then Pulp.
What surrounds the outer exterior of the lower dentine below the cervical margin?
Cementum surrounds the outer exterior of the lower dentine below the cervical margin.
What are the ideal properties of tooth?
Strong
Hard
Wear Resistant
Resistant to Chemical Damage
Ability to respond to damage
Ability to repair
Aesthetic
What does the enamel enable the tooth?
The enamel enables the tooth to be strong, hard and wear resistant. It is a mineralized tissue.
What part of the tooth is Vital, what part of the tooth isnt?
Dentine and pulp is vital, enamel is not.
What does the term vital mean?
The term vital means that the part of the tooth can respond to damage and repair itself.
What makes up each hard dental tissue?
Each hard dental tissue has different levels of composition regarding their Mineral, Matrix and Water content.
What does high mineral content result in?
High Mineral Content results in a brittle and easy to break dental tissue.
What does Lower Mineral Content + Higher Organic Material result in?
Lower Mineral Content + Higher Organic Material means more shock/stress absorbent/ flexible meaning it can prevent fracturing of more harder, higher mineralised tissues.
What are some key points about Enamel?
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
What is necessary regarding the enamel bur?
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.
How can unsupported enamel be easily fractured?
Un-supported enamel is easily fractured with a hand instrument e.g. chisel
What are some key points about Dentine?
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
What is Dentine made up of?
Dentine is made up of Collagen Fibres
What are the different burs that can be used for dentine?
Depending on the Dentine, different burs can be used.
What kind of burs can be used for sound dentine?
2 options -
Diamond burs (high speed)
Bladed burs (Low/high speed)
What burs can be used for Carious Dentine?
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
How is dentine growth pre-eruption?
Pre-eruption, dentine forms quickly
What happens to the rate of dentine growth as the age of person increases?
As age of person increases, Dentine Growth decreases
Is tubule density and character consistent in every site/location in dentine?
Depending on the site/location in dentine, there are variations in tubule density and character.
What do the cells of dentine line up against?
Cells of dentine line up against the enamel and pulp.
What happens to the site, the more closer it is to the bone?
The more closer the sight to the bone, the more porous the tubules.
What dentine layer is closest to the pulp?
Predentine is the layer close to the pulp.
What layer of dentine is close to the enamel?
Amelodentinal Junction is the layer close to the enamel.
How do fillings stay in the mouth?
Fillings have mechanical retention
How are fillings bonded to enamel?
They are bonded to enamel via:
* Acid etch - “glue”
* And utilises structure enamel
How are fillings bonded to dentine?
They are bonded to Dentine via:
* Acid demineralisation dissolves organic material to increase retention
* Infiltrate collagen with resin
* Penetrate Tubules with resin
What is dental pulp?
- It is a specialised connective tissue
- Essentially a matured Dental Papilla
- Dentine is the calcified tissue of the pulp
It is vital
Is dental pulp vital?
Dental pulp is vital.
What are the functions of dental pulp
Pulp Functions
* Dentine Formation
* Defence and Repair
* Sensory
What parts does the dental pulp consist of?
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
What consists of Apical Anatomy?
Cementum
Radiographic Apex
Apical Constriction
Cemento-dentinal Junction
Apical Foramen
When does the tooth end?
The end of the teeth is at the end of the pulp.
Why are lateral canals not very good for root canal treatments?
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.
How can the nerves and blood supply be cut off?
The nerves and blood supply can be cut off by being squashed by the alveolar bone and apex.
However, a periodontal ligament prevents this.
How is the Dentine and Pulp linked?
The Dentine and Pulp is linked:
Embryologically
Physically
Functionally
What can happen as a result of dentine being porous?
Any material / procedure may irritate pulp resulting in inflammation
Some materials are “therapeutic” - CA(OH)2 Calcium Hydroxide which can help generation of dentine
What are the flaws of pulp?
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.
What is Cementum?
- Mineralised Tissue
- Mineralised Specialised Connective Tissue
- Covers Tooth Roots
- Tooth support
Resistant to resorption.
What is the Cementum-Enamel Relationship?
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.
