Who developed SDA concept
Kayser 1981
What is SDA concept
20 teeth
3-5 occlusal units
(Occluding premolars= 1 unit, occluding molars= 2 units)
What are the indications for SDA
Missing posterior teeth with 3-5 OU remaining
Sufficient occlusal contact to provide a large enough occlusal table
Favourable prognosis for remaining anterior and premolar teeth
- will only work long term if remaining natural dentition can be preserved for remainder of the lifetime of the pt
What are contraindications for SDA
Poor prognosis for remaining dentition
Untreated/ advanced perio disease
Pre existing TMD
Pathological toothwear
Severe class II or III malocclusion
What are the benefits of SDA
Less tx
Less cost
Applicable for more pts
What type of tooth migration is common in SDA?
Distal tooth migration
What are some problems caused by SDA?
Increased anterior load, increased intensity of occlusal contact, increased interdental spaces
Why is toothwear a contraindication for SDA?
Long term prognosis for survival of teeth is poor
Gradual loss of occluding contacts and occlusal stability
What are the 5 requirements of occlusal stability?
- Stable contacts on all teeth of equal intensity in centric relation
- Anterior guidance in harmony with the envelope of function
- Disclusion of all posterior teeth during mandibular protrusive movement
- Disclusion of posterior teeth on the non-working side during mandibular lateral movement
- Disclusion of posterior teeth on working side during mandibular lateral movement
What are the 4 manifestations from a traumatic occlusion?
- fracture of restoration and/ or teeth
- tooth mobility
- dental pain not explained by infection
- tooth wear
When is failure of SDA most common?
Unstable periodontal disease, occlusal derangement, progressive toothwear
