Vertical Dimension in Edentulous Patients: Digital Approach

Understanding the vertical dimension (VD) in edentulous patients is crucial for ensuring optimal function and aesthetics of dentures. The integration of digital methods with traditional techniques provides a comprehensive approach to acquiring vertical dimension. This blog post delves into the workflow of setting VD in edentulous cases using the simplest and most effective methods.

 

Traditional Methods for Determining Vertical Dimension in Edentulous Patients

  1. Patient Evaluation: The process begins with assessing the patient’s facial aesthetics and anatomical features. Pre-extraction records and photographs are reviewed to guide restoration plans.
  2. Physiological Rest Position: Measuring from the tip of the nose to the chin while the patient is relaxed gives the vertical dimension at rest (VDR). This measurement is foundational for the next steps.
  3. Estimation of Occlusal Vertical Dimension (OVD): From the VDR, subtract about 2 to 4 millimeters to accommodate functional occlusion. This adjustment is essential for comfort and effective mastication.
  4. Phonetic Methods: Having the patient pronounce specific phonetic sounds helps fine-tune the vertical dimension accurately.
  5. Trial Denture Setup: A trial denture is created to evaluate aesthetics, phonetics, and functionality. The patient wears this trial to assess comfort and usability, providing valuable feedback.
  6. Adjustments Based on Feedback: Adjustments are made based on the patient’s feedback and observations. This step is crucial for achieving the best fit and function of the dentures.
  7. Finalization: Once the ideal vertical dimension is confirmed and the patient is comfortable, the denture is finalized, ensuring a well-fitting and functional outcome.

 

Integrating Digital Technologies with Traditional Methods

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Digital Scanning

Digital intraoral scanning has replaced alginate for obtaining preliminary impressions. This method captures precise digital impressions of the patient’s oral cavity quickly and comfortably, minimizing errors and reducing discomfort.

Computer-Aided Design (CAD)

With digital impressions available, CAD is used to design and visualize dentures with remarkable accuracy. This technology facilitates rapid design changes and ensures precision in both temporary and final denture production.

3D Printing

After finalizing the design, 3D printing is employed to create the denture. This technology accelerates the production process, allows for easy replication and modification of dentures based on feedback, and significantly reduces material waste and overall treatment time.

Feedback Loops

Digital tools enable dynamic feedback loops. As patients test their dentures, precise data on fit and functionality is gathered. This data is used to make necessary adjustments in the CAD software. The revised design can be quickly reprinted for further testing, ensuring the dentures are optimized for comfort and functionality before finalization.

 

The Three Pillars of Denture Fabrication

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1. Final Impressions

Precision starts with final impressions that capture the exact contours of the patient’s oral structures. Accurate impressions are crucial for designing dentures that fit seamlessly.

2. Vertical Dimension

Determining the correct VD is crucial for the aesthetic and functional integration of the dentures with the patient’s facial features. It influences chewing efficiency and facial expressions.

3. Centric Relation

Centric relation (CR) defines the optimal relationship of the jaw in three-dimensional space. Accurate CR ensures the dentures allow for effective bite and natural jaw movement, preventing joint discomfort or uneven wear on the denture.

 

Case Study: Hybrid Approach

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The case study combines traditional and digital methods to achieve optimal results in denture fabrication.

 

1. Preliminary Impression

Intraoral Scan replaces traditional impression materials, providing a digital map of the oral cavity. This method offers fast, accurate, and comfortable preliminary impressions.

 

Detailed Workflow: Preliminary Scan

  • Maxillary Arch Scanning: Turn off the intraoral scanner’s smart color filter to capture soft tissue details accurately. Begin with stable regions like the hard palate, then move to dynamic areas.
  • Mandibular Arch Scanning: Disable the smart color filter for clarity. Start from immovable tissue areas and proceed to more flexible regions, capturing the buccal and lingual sulcus accurately.
  • Overall Scan Accuracy: Carefully scan the alveolar ridges and buccal and lingual vestibule to record all anatomical features.

 

2. 1st Intermaxillary Relation

Centric Tray is used to establish the initial relationship between the upper and lower jaws, recording the base jaw relation accurately.

 

Detailed Workflow: Centric Tray

  • Initial Setup: Position the centric tray in the patient’s mouth to record the preliminary vertical dimension and jaw relationship with impression material.
  • Bite Registration: Guide the patient to bite down, capturing the contours of the edentulous ridge.
  • Scanning Process: Scan the tray impressions to get a digital bite registration.
  • Alignment: Align the scan data of the upper and lower jaws using tray inversion for correct mesh orientation.
  • Alternative Method – Cotton Rolls: You can use cotton rolls to set the vertical height between arches, enhancing the inter-arch relationship.

 

3. Final Impression

A 3D printed Individual Tray is utilized for the final impression, custom-designed for the patient to ensure accurate capture of oral structures.

 

Detailed Workflow: Final Impression

  • Tray Preparation: Apply adhesive to the tray for proper impression material adherence.
  • Primary Impression: Use a heavy body impression material around the tray borders to capture edentulous area contours.
  • Secondary Impression: Apply light body impression material over the tray surface for a comprehensive dental anatomy capture.

 

4. Vertical Dimension and Centric Relation

The Gnathometer M accurately records the vertical dimension and centric relation of the jaws, providing precise data for final denture adjustments.

 

Detailed Workflow: Gnathometer M

  • Initial Setup: Attach the Gnathometer M to the patient’s mouth.
  • Jaw Movements: Instruct the patient to bite down and move the jaw forward, backward, and side to side, tracking all directions of movement.
  • Data Collection: Accurately determine the jaw’s centric relation.
  • Design Integration: Use Medit Design to design an individual tray compatible with the Gnathometer M. Import jaw models, adjust offsets, draw and finalize splint margins, and combine the splint with jaw scans.
  • Final Design: Merge the splint and rim to complete the tray design, ensuring precise dental impressions.

Mandible Movement Tracing

  • Vertical Dimension Setting: Attach the Gnathometer M and adjust screws to set the appropriate vertical dimension.
  • Centric Relation Adjustment: Move the mandible forward, backward, and side to side to accurately determine the centric relation.

 


 

By combining traditional and digital methods, dental practitioners can achieve optimal results in denture fabrication, ensuring precision and efficiency throughout the process.

 

Click on the video above, or visit Medit Academy channel if you want to see a more detailed walkthrough of the actual case.

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