How Dental Zirconia Crowns Are Made in the Dental Lab
Zirconia crowns have become a gold standard in restorative dentistry due to their strength, durability, and natural appearance. Crafting these crowns in a dental laboratory is a precise and technologically advanced process that combines artistry with cutting-edge tools. In this blog, we’ll take you behind the scenes to explore how dental zirconia crowns are made in the lab, from initial impressions to the final polished product.
Step 1: Receiving the Dental Impression
The process begins with the dentist providing the dental lab with an impression of the patient’s tooth. This can be a traditional physical mould or, more commonly today, a digital scan created using intraoral scanners. The impression captures the exact shape, size, and position of the prepared tooth and surrounding teeth to ensure the crown fits perfectly.
- Digital Scans: Modern labs often receive 3D digital models via software, which offer high accuracy and eliminate the need for physical moulds.
- Physical Impressions: If a traditional mould is used, the lab creates a stone model by pouring dental stone into the impression, replicating the patient’s oral anatomy.
Step 2: Designing the Crown with CAD Software
Once the impression or digital scan is received, the lab uses Computer-Aided Design (CAD) software to design the zirconia crown. This step is critical for ensuring the crown’s fit, function, and aesthetics.
- Digital Modelling: A dental technician imports the 3D scan into CAD software, where they design the crown’s shape, size, and contours. The software allows precise adjustments to match the patient’s bite and the natural curvature of their teeth.
- Customization: The technician considers factors like the tooth’s position (front or back), the patient’s bite alignment, and aesthetic preferences, such as colour matching to adjacent teeth.
- Material Selection: The lab chooses the type of zirconia—solid for strength or high-translucency for aesthetics—based on the dentist’s specifications.
This digital design phase ensures the crown is tailored to the patient’s unique dental anatomy, balancing functionality with a natural look.
Step 3: Milling the Zirconia Crown
After the design is finalized, the CAD file is sent to a Computer-Aided Manufacturing (CAM) machine, typically a CNC (Computer Numerical Control) milling machine, to create the crown from a zirconia block.
- Zirconia Blocks: Zirconia is supplied in pre-sintered blocks or discs, which are softer and easier to mill. These blocks come in various shades to match the patient’s natural teeth.
- Milling Process: The milling machine carves the crown with extreme precision, following the CAD design. This process can take anywhere from 10 to 30 minutes, depending on the complexity of the crown and the machine’s capabilities.
- Precision and Accuracy: Modern milling machines use diamond-coated tools to achieve fine details, ensuring the crown fits the prepared tooth perfectly.
At this stage, the crown is in a “green” (pre-sintered) state, meaning it’s softer and slightly larger than the final product to account for shrinkage during the next step.
Step 4: Sintering the Zirconia
Sintering is the process of heating the milled zirconia crown in a specialized oven to achieve its full strength and density. This is a crucial step that transforms the soft, chalky zirconia into a hard, durable restoration.
Step 5: Finishing and Polishing
Once sintered, the zirconia crown is incredibly strong but may require additional finishing to perfect its shape and appearance.
- Adjustments: A technician checks the crown’s fit on the dental model (or digital scan) and makes minor adjustments using diamond tools to refine the contours or contact points.
- Polishing: The crown is polished to achieve a smooth, glossy surface that resists plaque buildup and feels comfortable in the mouth. For high-translucency zirconia, polishing enhances its natural shine.
- Staining and Glazing (Optional): To improve aesthetics, the lab may apply stains or glazes to mimic the natural colour variations of teeth.
This is especially common for front teeth, where lifelike translucency is key. The crown is fired again at a lower temperature to set the glaze.
Step 6: Quality Control and Delivery
Before the crown is sent to the dentist, it undergoes rigorous quality control to ensure it meets the required standards.
- Fit and Accuracy: The crown is tested on the dental model or digital scan to confirm proper fit, alignment, and bite.
- Aesthetics: The technician verifies that the color, translucency, and shape match the patient’s natural teeth.
- Durability: The lab ensures the crown is free of cracks, chips, or manufacturing defects.
Once approved by our experienced technicians at Precision Smiles Dental Lab, the crown is carefully packaged and shipped to the dentist.
Technology and Expertise in Zirconia Crown Production
The creation of zirconia crowns relies heavily on advanced technology, such as CAD/CAM systems and high-precision milling machines. However, the expertise of dental technicians is equally important. Their skill in designing, adjusting, and finishing the crown ensures it meets both functional and aesthetic expectations. Many labs also use 3D printing for temporary models or to create guides for complex cases, further enhancing precision.
Why Zirconia Crowns Are Worth the Effort
The meticulous process of crafting zirconia crowns results in a restoration that is:
Conclusion
The creation of dental zirconia crowns in the lab is a fascinating blend of technology, science, and craftsmanship. From digital design to precision milling and high temperature sintering, each step is carefully executed to produce a crown that restores both function and beauty to a patient’s smile. By understanding this process, dentists and patients can appreciate the artistry and expertise behind their dental restorations, making zirconia crowns, made by the team at Precision Smiles Dental Lab, a top choice for your restorative treatments.
- Durable: Zirconia’s strength makes it ideal for long-lasting restorations, often exceeding 15 years with proper care.
- Aesthetic: Its ability to mimic natural teeth ensures a seamless smile. • Biocompatible: Zirconia is safe for patients with metal allergies and promotes healthy gums.
