Prosthodontics
What this domain tests
Questions test denture construction sequence and anatomical landmarks, removable partial denture design and Kennedy classification, fixed prosthodontic principles, and implant prosthodontics and occlusion.
Complete dentures
- Impressions: primary alginate, border moulding with modelling compound, then wash impression; the posterior palatal seal lies between the vibrating line and the fovea palatinae.
- Landmarks: incisive papilla, retromolar pad, hamular notch, buccal shelf, genial tubercles; the neutral zone is where tongue and cheek forces balance.
- Record jaw relation, set teeth with balanced occlusion, and verify at try-in. Christensen phenomenon is the anterior open space in protrusive movement when occlusion is not balanced.
- Denture stomatitis is usually Candida-related; treat with hygiene, removal at night and topical antifungal.
Removable partial dentures
- Kennedy classes I-IV, with Applegate's rules for classifying after extractions and using the most posterior edentulous area.
- Components: rests, major connector (lingual bar, palatal strap, horseshoe), minor connector, direct retainer, reciprocation, guide planes and indirect retainers.
- Circumferential (Akers) clasps give good retention; the RPI system (rest, proximal plate, I-bar) reduces torque on abutments.
Fixed and implant prosthodontics
- Margin placement, taper (ideally 6 degrees), resistance and retention form, and a ferrule of 1.5-2 mm of sound dentin.
- Pontic design: sanitary, modified ridge lap, ovate; consider cleansability and aesthetics.
- Osseointegration depends on primary stability, minimal heat, and unloaded healing; success criteria require less than 0.2 mm annual bone loss after the first year.
- Occlusal schemes: mutually protected occlusion with anterior guidance in maximum intercuspation and disclusion in excursions; group function as an alternative.
Worked example
A patient is missing 36 and 46, and 37 and 47 remain. Reasoning: both edentulous areas are bounded posteriorly by natural teeth, so each is Kennedy class III. If 47 were later extracted, the classification would be reassessed after healing and would become class II. Applegate's rules require classification after any planned extractions rather than at first presentation.
Traps
Using the anterior edentulous space to classify; forgetting indirect retention in class I and II designs; ignoring the ferrule requirement; setting denture teeth without balanced occlusion.