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
Why do we have a PDL?
Retention of the tooth - via gomphosis joint system
What is ankylosis?
Fusion between alveolar bone and the cementum of the teeth
What is gomphosis?
Fibrous mobile root-and-socket joint
How can teeth be joined to the bone?
How are teeth joined in HUMANS?
Ankylosis or gomphosis
GOMPHOSIS
we do NOT have ankylosis - sharks have ankylosis
What is the function of the PDL?
Why do we need a joint?
Aka why gomphosis?
Joint absorbs pressure
Occlusal loading and PDL
What effect does occlusal loading have on the 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
What is hypofunction of PDL?
What does hypofunction of PDL lead to ?
Reduced function of the PDL
(Eg when you have less occlusal loading / stress to the pdl/tooth)
Reduced loading = narrow PDL
Results in:
- bone formation
- narrowing of ligament space
- hyalinisation of the ligament fibres
Collagen fibres are disorganised with lower intensity and patchy appearance
Occlusal loading and PDL
Hyperfunction of pdl 1
what is hyperfunction of PDL?
What does hyperfunction of PDL lead to?
An example would be in orthodontics - this example is UNIDIRECTIONAL
Google def - hyperfunction is excessive function
There is a pressure side and a tension side
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
What does normal organisation of PDL depend on?
Continued mechanical stimulation by occlusal forces
What happens to the PDL in response to increased loading?
The PDL remodels and shows adaptive changes
Are these changes reversible following removal of these forces?
YES
Why is occlusal loading associated with clinically?
Clinically associated with increased mobility and widening of PDL Radiographically
Increased motility
Widening of PDL radiographically
What is the result of occlusal load on a tooth?
Tooth Mobility
Tooth mobility is ultimately the result of the occlusal load on a tooth.
Occlusal loading and PDL
Recap
Occlusal trauma lecture
