The shortened dental arch Flashcards
What is the SDA Concept?
- Proposed by Kayser 1981
- A dentition where most posterior teeth missing
- Satisfactory oral function without use of RPD
- Priority given to maintaining anterior and premolar dentition in one or both jaws
- In right circumstances , non replacement of posterior missing teeth can provide stable and acceptable dentition
What is the definition of occlusal stability?
- Absence of the tendency for teeth to migrate other than the normal physiological compensatory movements occuring over time
- Or The stability of tooth positioning relative to its spatial relationship in the occluding dental arches
What factors determine Occlusal stability?
- Periodontal support
- Number of teeth in dental arches
- Interdental spacing
- Occlusal contacts
- Tooth wear
In the SDA concept what gives sufficient adaptive capacity?
- Gives sufficient adaptive capacity when 3-5 occlusal units are left
What classifies as 1 unit in SDA concept?
- Pair of occluding premolars
What classifies as 2 units in SDA concept?
- Pair of occluding molars
What are loss of molars associated with (in terms of problems)?
- Reduced masticatory efficiency
- Mandibular displacement
- Alterations in food selection
- Aesthetic issues
- Loss of occlusal stability
- TMJ problems
What is the 1992 World Health Organisation statement on amount of teeth we need?
- “the retention, throughout life, of a functional, esthetic, natural dentition of not less than 20 teeth and not requiring recourse to prostheses should be the treatment goal for oral health”
What are the indications for a txt plan with application of SDA?
- Missing posterior teeth with 3-5 OU remaining
- Sufficient occlusal contacts to provide large enough occlusal table
- Favourable prognosis for remaining anterior and premolar teeth
- Pt not motivated to pursue complex txt plan
- There are limited financial resources for dental
When will SDA work long term?
- Only work long term if remaining natural dentition can be preserved for remainder of lifetime of pt
What are the contraindications for application of SDA concept in txt plan?
- Poor prognosis for the remaining dentition
- Untreated or advanced periodontal disease
- Pre-existing temporomandibular joint dysfunction
- Signs of pathological tumour
- Pt has significant malocclusion i.e. Severe Class II or Class III
If any one of these are met then consider replacing posterior teeth
If you have broken down dentition what are the two options for txt plan?
- Restore complete dental arches (28 teeth)
- Restore reduced dental arches (SDA:20-24 teeth)
What are the pros and cons of restoring complete dental arches?
- More complicated txt
- Higher cost
- Too expensive for many pt or health care systems
- Better results?
Pros and cons of restoring reduced dental arches?
- Less complicated txt
- Lower cost
- Applicable for more pt
- Txt result worse perhaps?
What are some considerations you have to make about pt when deciding to adopt the SDA concept or restore full dentition?
- Does pt have any problems chewing food?
- Does pt have appearance or cosmetic concerns from missing teeth?
- Does pt have discomfort arising from missing teeth?
- Any evidence of occlusal instability as result of missing teeth?
If yes to any one of these then consider replacing missing teeth