Prosthodontics and Implantology
This domain tests replacement of missing teeth with removable, fixed and implant-supported prostheses: design principles, occlusal records, material choice and the biological limits that decide implant success.
Complete dentures
Success rests on support (from the denture-bearing area), retention (from seal, adhesion and cohesion) and stability (resistance to displacement). Record the occlusion at the correct occlusal vertical dimension and centric relation, verify at try-in, and use balanced occlusion in the eccentric positions. A neutral zone approach helps where the residual ridge is severely resorbed.
Removable partial dentures
Classify the arch with Kennedy (I to IV) and apply Applegate's rules, which state that the classification is determined after any necessary extractions, that the most posterior edentulous area governs, and that a third molar is not counted if it is not to be replaced. Rests direct load along the long axis of abutment teeth; clasps provide retention and bracing; major connectors (lingual bar, lingual plate, palatal plate) should be rigid and avoid gingival margins.
Fixed prosthodontics and materials
Assess abutment support; Ante's law is a guide rather than a rule. Margin design must allow a detectable, cleanable finish line. Zirconia offers strength, lithium disilicate offers aesthetics and adhesion, metal-ceramic remains predictable. Cementation choice follows the material: resin bonding for etchable glass ceramics, conventional cement for zirconia where retention is adequate.
Implants
Osseointegration depends on biocompatible surface, primary stability, atraumatic site preparation, adequate bone volume and density, and controlled loading. Success criteria (Albrektsson) require an immobile implant, no peri-implant radiolucency, bone loss under about 0.2 mm annually after the first year, and no pain, infection or neuropathy. Distinguish peri-implant mucositis (bleeding, no bone loss, reversible) from peri-implantitis (inflammation plus progressive bone loss).
Worked example
A mandibular first molar site has 6 mm ridge width and 9 mm of bone above the mandibular canal on CBCT. Reasoning: a 4.0 mm diameter implant leaves roughly 1 mm of buccal and lingual bone, acceptable; an 8 mm length preserves a 2 mm safety margin above the canal (commonly 1.5–2 mm). Shorter implants of 6–8 mm are well supported in the posterior mandible, provided the canal margin is respected.
Traps that cost marks
- Increasing occlusal vertical dimension without justification, causing soreness and accelerated resorption.
- Describing mucosa as supporting a fixed implant prosthesis.
- Calling peri-implant mucositis peri-implantitis when there is no bone loss.
- Ignoring the safety margin above the inferior alveolar canal during drilling.