Intro
This is just a collection of tips and useful info from class
Tips
- We’re making the crown in relation to the long axis of the occlusal surface
- its confusing because normally that seems like its in relation to the long axis of the tooth
- Its okay to have an undercut! It’s about fixing things as they go along
- For the occlusal reducation make it through through the peak height at the cusps, don’t worry about the grooves too much!
OCHWA Reduction Guidelines
Tooth Reduction Based on Material
Metal-ceramic / PFM
| Reduction in mm | Anterior | Posterior |
|---|---|---|
| Incisal / Occlusal | 2 | 2 Functional cusp 1.5 Non-functional cusp |
| Axial | 1.5 | 1.5 |
| Margin | 1.5 | 1.5 |
All-ceramic / Full-ceramic
| Reduction in mm | Anterior | Posterior |
|---|---|---|
| Incisal / Occlusal | 1.5 | 2 Functional cusp 1.5 Non-functional cusp |
| Axial | 1 | 1 |
| Margin | 1 | 1 |
Metal Crown (Posterior)
| Reduction in mm | Posterior |
|---|---|
| Occlusal | 1.5 Functional cusp 1 Non-functional cusp |
| Axial | 1 |
| Margin | 0.5–1 |
Functional vs Non-functional Cusps
- Functional cusps (also called supporting cusps):
- Maxillary lingual cusps
- Mandibular buccal cusps
- These maintain the vertical dimension and contact opposing fossae/marginal ridges in centric occlusion.
- Non-functional cusps (also called guiding cusps):
- Maxillary buccal cusps
- Mandibular lingual cusps
- These guide mandibular movement and protect soft tissues but do not bear heavy occlusal loads.