1. Occlusal Trauma - Periodontal Physiology and concepts of occlusal loading of teeth Flashcards
What does periodontium consist of ?
PDL
Gingiva
Alveolar bone
Root cementum
Diagram
What is the width of the PDL ( when healthy ) ?
Roughly 0.25 mm
(0.2-0.4 mm)
What is biologic width ?
Width from the tip of the alveolar crest of the bone to the tip of the gingival epithelium
1
Why do we have a PDL?
2
What does a PDL do (simple)
1
Retention of the tooth - via gomphosis joint system
2
connects tooth to bone, like a joint
What is ankylosis?
Fusion between alveolar bone and the cementum of the teeth
What is gomphosis?
Fibrous mobile root-and-socket joint
1
How can teeth be joined to the bone?
2
How are teeth joined in HUMANS?
3
Why is gomphosis important
1
Ankylosis or gomphosis
2
GOMPHOSIS
we do NOT have ankylosis - sharks have ankylosis
3
- we put pressure when we chew, so need to distribute the pressure of the occlusion onto the bone and pdl
What is the function of the PDL?
Why do we need a joint?
Aka why gomphosis?
Joint absorbs pressure
(If have arthritis then no joint to absorb pressure that we have on occlusion in mastication)
Occlusal loading and PDL
Occlusal loading causes PDL to change - width can change and also in orthodontics - relies on PDL
How is PDL width maintained?
Occlusal loading and PDL
1
What is hypofunction of PDL?
2
What does hypofunction of PDL lead to ?
Reduced function of the PDL
(Eg when you have less occlusal loading / stress to the pdl/tooth)
1
Reduced loading = narrow PDL
2
Results in:
- bone formation
- narrowing of ligament space
- hyalinisation of the ligament fibres
(When we take the load in)
Collagen fibres are disorganised with lower intensity and patchy appearance
IMPORTANT TO UNDERSTAND IT DOES NOT GET NARROWER, IT CHANGES IT ORGANISATION + PHYSIOLOGY
Occlusal loading and PDL
Hyperfunction of pdl 1
what is hyperfunction of PDL?
2
What does hyperfunction of PDL lead to?
An example would be in orthodontics - this example is UNIDIRECTIONAL
Google def - hyperfunction is excessive function
EG excess pressure on tooth
There is a pressure side and a tension side
2
Hyperfunction of PDL leads to :
Thicker PDL and bone resorption
Results In pain and tooth mobility
Pressure side is where it touches
Hyperfunction of pdl 2
What happens in the pressure side?
What happens in tension side?
Pressure Side
• loss of fibre orientation
• osteoclastic bone resorption
• localised areas of pressure necrosis
• (ankylosis)
Tension Side
• Stretching of fibres
• Bone formation
When does occlusal trauma occur?
3 examples of what can cause occlusal trauma to occur?
Multidirectional forces
- Abnormal occlusal function
- occlusal disharmonies - Absence of neuromuscular control of mastication
- parafunction (eg bruxism) - Abnormal occlusal support (PDL)
- periodontitis
Occlusal loading and PDL
Recap
Occlusal trauma can be caused by?
(3)
Examples of occlusal disharmonies
Examples of parafunction?
(Abnormal function)
1) Bruxism / clenching habits
2) chewing habits eg biting nails, smoke pipe, chewing tobacco ( go back and check lecture to see if it says about tobacco)
Periodontal disease
How does it affect PDL?
(Example of occlusal trauma )
Reduces surface area of PDL
• In periodontal disease a normal masticatory force produces an abnormal occlusal load (as less PDL)
• Particularly marked in the presence of co - factors such as occlusal disharmonies.
What is primary occlusal trauma?
Excessive occlusal load on periodontally healthy teeth
What is secondary occlusal trauma?
Excessive occlusal load on periodontally diseased teeth
Does occlusal trauma cause periodontitis?
Does occlusal trauma impact healing?
No
No
What does occlusal loading cause?
Does occlusal loading cause periodontal disease?
Recap
