Manage 360° Scanning for Complete Dentures and Wax Rims

Overview: This guide explains how to establish a repeatable scan path for complete denture cases to ensure a precise appliance fit and provides steps to resolve common scan errors. 

Lower Denture or Wax Rim Extraoral Scanning Steps

To capture a high-quality lower scan, follow the sequence: Intaglio → Borders → Occlusal → Cameo.

1. Intaglio Surface: Begin scanning on the intaglio (inner) surface of the lower appliance.

2. Peripheral Borders: Use a "rocking and rolling" motion to move the scanner from the intaglio toward the border, then roll back toward the intaglio. Repeat until the entire border is captured.

3. Cameo Surface: Rock the scanner from the buccal border toward the buccal/facial surface, then roll back toward the border.

4. Occlusal Surface: Rock the scanner from the buccal surface to the occlusal and lingual surfaces, then roll back toward the occlusal until all surfaces are scanned.

5. Data Evaluation: Check the digital model for missing data and rescan the lower appliance if gaps are found.

Upper Denture or Wax Rim Extraoral Scanning Steps

To capture a high-quality upper scan, follow the sequence: Intaglio → Borders → Occlusal → Cameo.

1. Intaglio and Palate: Begin on the intaglio surface. Slowly sweep the scanner from side to side to capture the majority of the palate.

2. Peripheral Borders: Use a "rocking and rolling" motion to move the scanner from the intaglio over the border and back. Repeat until the entire border is scanned.

3. Cameo Surface: Rock the scanner from the buccal border toward the facial surface and back until all buccal surfaces are captured.

4. Occlusal Surface: Rock the scanner from the buccal surface to the occlusal and lingual surfaces, then roll back to the occlusal.

5. Data Evaluation: Check the digital model for holes and rescan the upper appliance as needed.

Capture the Bite Registration

1. Place the upper and lower prostheses in the patient's mouth and confirm correct occlusion.

2. Apply blue bite registration material to stabilize the bite and prevent movement.

3. Scan the first intraoral bite from the molar area to the midline.

4. Scan the second intraoral bite from the molar area to the midline on the opposite side.

Identify High-Quality Scan Characteristics

Change the scan color to stone on the review page to verify the following characteristics:

• Complete Data: No missing information on the occlusal or intaglio surfaces.

• Solid Connection: No unconnected data or visible gapping.

• Anatomy Focus: A consistent impression that only captures intraoral anatomy without lifted edges.

• Alignment: An accurate and stable bite alignment. 

Troubleshoot Common Scan Errors

Use these steps to resolve specific scan quality issues:

• Missing Scan Data: Start the scanner on an area it easily recognizes, then move slowly toward the gap.

   

• Stitching Errors: Use the surface trim tool to delete improperly stitched data. If a large section of data is not connected, reset the scan and start again. 

  

• Incorrect Bite Alignment: Address any issues with the individual arch scans first, then reset and rescan the bite. Ensure you capture 2-3mm of the buccal surface of both the upper and lower arches. 

Helpful Tips

• Remember that the scan on the screen is a 3D representation of the appliance in your hand. As you rotate the model on the screen to check for completeness, rotate the denture or wax rim in your hand similarly.
• The clinician should be positioned directly in front of the screen with the scanner in the dominant hand and the appliance in the non-dominant hand.
• Scanning hard-to-reach areas requires moving both the appliance and scanner simultaneously, and twisting each to capture deep anatomy or narrow spaces.
• If the scanner stops tracking, move back to an area that the scanner can identify easily before slowly moving towards new data.
• After using a bur or carver to mark the anatomical landmarks on an appliance, add additional markings to the exterior that don’t interfere with the anatomical markings. 
  • This gives the scanner additional reference points when stitching data.
• Move slowly enough for the scanner to pick up the detail, but keep your movements steady and deliberate. It always needs a visible reference point so it can anchor new data to what’s already been captured

Troubleshooting Common Scanning Issues