Fixed Prosthodontics: Clinical Tips & Protocols
Technical Guidance for Superior Restorative Outcomes
Modern Dental Creations is committed to clinical excellence. To ensure your fixed restorations require minimal chairside adjustment and meet the highest aesthetic standards, we have compiled the following technical protocols. These guidelines assist in capturing the precise data our laboratory needs for successful case fabrication.
Retrofitting Crowns to Existing Partials
Analog Technique (Physical Impressions)
If a patient cannot part with their partial denture during crown or bridge fabrication, we can utilize a partial index.
- The Process: Follow our illustrated step-by-step guide to create a localized matrix.
- Lab Standard: While clinicians often use resin, our laboratory fabricates internal matrices using high-strength non-precious alloys. This prevents the fractures common with Duralay, ensuring the crown fits the framework perfectly.
Digital Technique (Intraoral Scanning)
Designing a crown to fit an existing partial in a digital workflow requires three distinct scans to ensure all contact points are captured:
- Preparation Scan: Capture the prepped abutments and edentulous spaces with traditional tissue retraction.
- In-Situ Scan: With the partial fully seated in the mouth, scan the entire quadrant or arch. Ensure the scan clearly captures all clasps, rests, lingual plates, and major connectors in their active position.
- Standalone Partial Scan: Scan the partial denture by itself on a tabletop. Capture both the intaglio and cameo surfaces of all rests and clasps. This "extra-oral" data allows us to refine the internal surfaces of the clasps that the intraoral scan often misses due to shadowing.
Horizontal Reference: The Bite Stick Protocol
For full-arch or multi-unit anterior cases, a bite stick (horizontal reference) prevents a canted midline or skewed occlusal plane by orienting the models to the true horizon.
Technique:
- Reference: Use a level to place a horizontal reference (like tape or a door frame) in the patient's field of view.
- Application: Apply PVS bite material to the anterior region and have the patient close into centric relation.
- Alignment: While the material is unset, insert a rigid stick (e.g., a cotton swab or brush) facial to the teeth. Align the stick so it is perfectly parallel with your horizontal reference.
- Stabilization: Add more PVS to "lock" the stick in position.
- Lab Use: We align the stick parallel to our workstation to ensure the incisal edges are level with the patient’s face, regardless of any intraoral asymmetries.