7 - Shortened dental arch Flashcards
What dental disease is common in RPD wearers?
- root caries
- periodontal disease
Why is dental disease common in RPD wearers?
Patients are already higher risk
What is the Kayser 1981 concept?
- SDA concept
- dentition where most posterior teeth are missing
- satisfactory oral function can be achieved without RPD
- priority is given to maintaining anterior and premolar in one or both jaws
- sufficient capacity is achieved when 3 to 5 occlusal units are left
What is an occluding unit?
- pair of occluding premolars = 1 unit
- pair of occluding molars = 2 units
What symptoms are associated with loss of molars?
- reduced masticatory efficiency
- mandibular displacement
- alteration in food selection
- aesthetic issues
- loss of occlusal stability
- TMJ problems
What are the indications for SDA?
- missing posterior teeth with 3-5 OU remaining
- sufficient occlusal contacts to provide occlusal table
- favourable prognosis for anterior teeth
- patient not motivated for complex Tx plan
- limited financial resources
What are the contraindications for SDA?
- poor prognosis for remaining dentition
- untreated or advanced perio
- pre-existing TMD
- pathological tooth wear
- significant malocclusion
What considerations should be taken before SDA?
- any problems chewing food?
- any appearance or cosmetic issues with anteriors?
- any discomfort?
- any evidence of occlusal instability?
What should be examined EO for an SDA?
- signs of TMD (click/crepitus/pain)
- hypertrophy of MOM
- skeletal relationship
What should be examined IO for an SDA?
- signs of bruxism (buccal keratosis/wear)
- periodontal assessment
- occlusal assessment
- teeth of poor prognosis
How should the occlusion be assessed for SDA?
- severe class II and class III are contraindicated as they have few OU
- edge to edge is okay
- 3-5 OU ideal
Why does significant periodontal disease contraindicate an SDA?
- drifting of periodontally involved teeth under occlusal load
- loss of alveolar bone leads to a compromised denture bearing area (long term) and loss of neutral zone
Describe pathological periodontal tooth movement in an SDA.
- distal tooth migration occurs due to anterior load
- increased occlusal intensity
- increased interdental spacing
- exacerbated by inadequate periodontal support
Why is progressive tooth wear a contraindication for SDA?
- long term threat to prognosis of teeth
- gradual loss of occluding contacts and stability (loss of centric relation)
Define occlusal stability.
Stability of tooth positioning relative to its spatial relationship in the occluding dental arches
