By David Hudnall, DMD
Routinely doing porcelain crowns? There’s nothing wrong with using a material that works well and has been the tried-and-true restorative workhorse for over 50 years. Meanwhile, dental research has brought newer formulations to the market that offer a variety of distinct advantages over the techniques that may have been the standard when you were in dental school.
Adapting manufacturing processes to dentistry has allowed for more aesthetic and durable restorative materials to enter the field that couldn’t have been considered. Zirconia is one material that has risen to be a top contender by combining its incredible strength with lifelike visual appeal. In contrast, gold crowns, which were historically the standard, are now less favored due to their cost and visibility, despite their durability.
What Are Zirconia Crowns?
Full-coverage zirconia crowns allow the patient to have the benefits of an extremely durable and long-lasting restoration while enjoying the natural appearance of improved aesthetics, especially when compared to traditional crowns like porcelain-fused-to-metal (PFM).
Because zirconia is available in several different chemical formulations, it may be used in a variety of dental restorations where a combination of strength and superior aesthetics are important. High translucent zirconia, with its enhanced translucency, effectively mimics the natural color of adjacent teeth.
Advantages of Zirconia Crowns
There are plenty of zirconia crowns advantages that make them worthwhile to use for patients. Discover the different reasons why zirconia crowns offer a positive solution for a variety of patients.
Biocompatibility
Zirconia is kind to the body. It is the same ceramic material used to make non-metallic medical joint replacements and all-ceramic dental implants, making it non-harmful to oral health. This reduces the risk of adverse tissue reactions, making it a safer option for many patients.
Metal-Free
Unlike PFM, zirconia doesn’t require a metal substructure for it to be strong and stable. There’s no metal to shine through and no unsightly metal margins. The lack of metal content is also beneficial to patients who are sensitized or allergic to metal, providing a safer alternative for those with sensitivities.
Strength and Durability
Zirconia is an extremely strong material without the bulky appearance of traditional porcelain. Monolithic zirconia crowns are particularly advantageous due to their strength and resistance to cracking. Its resistance to wear makes it difficult to fracture or crack. Because it offers more fracture resistance than other dental materials, it is nearly indestructible and stands up well to bruxism and parafunctional habits better than any other material currently available.
Zirconia is also a very suitable material for the fabrication of long-span bridges. It would not be uncommon for a zirconia crown to last 20 years or more, depending upon regular care and patient hygiene. Patients can enjoy long-term durability without frequent replacements, which is a significant advantage over other materials.
Milled To Exact Specifications
CAD/CAM technology allows zirconia crowns to be produced with a precise fit, greatly reducing the chair time required to adjust and cement these restorations. Zirconia restorations are best retained to the natural tooth structure using resin ionomer cements. The precision of digital manufacturing leads to better-fitting restorations, reducing the risk of future complications such as marginal gaps or misalignment.
Aesthetic
The translucent nature of zirconia reflects and picks up the color of surrounding teeth. Layered zirconia crowns combine the strength of zirconia with a porcelain layer to enhance aesthetics, mimicking the natural color gradient of teeth. Because it is manufactured in a wide variety of shades, it’s easy to accurately match the color to the patient’s natural teeth.
In addition, opaque monolithic zirconia can be used beneath translucent zirconia formulations to mask or hide underlying dark areas and intrinsic stains present in the tooth preparation. This makes zirconia an excellent choice for patients who have discoloration or staining issues that might otherwise affect the appearance of their smile.
Minimally Invasive Preparation
Zirconia crowns require less tooth reduction compared to other crown materials, preserving more of the natural tooth structure. This makes the procedure less invasive while still ensuring a secure and long-lasting fit. Retaining more of the natural tooth helps maintain overall oral health and can contribute to better long-term outcomes.
Resistance to Temperature Sensitivity
Unlike metal crowns, zirconia does not conduct temperature as much, which can reduce sensitivity to hot and cold foods or beverages. Patients who experience discomfort with metal-based crowns may find zirconia to be a much more comfortable and natural-feeling alternative.
In Summary
With advancements in dental materials and manufacturing, zirconia crowns have become a leading choice for both dentists and patients. Their combination of superior strength, longevity, and aesthetic appeal makes them a top-tier option over traditional materials like PFM and gold. Additionally, their biocompatibility and metal-free nature ensure they are a safe and effective choice for nearly all patients.
If you are considering updating your restorative options, zirconia crowns present an ideal balance between function and beauty, providing your patients with reliable, high-quality dental solutions for years to come.
Disadvantages of Zirconia Crowns
So, what are some of the zirconia crown problems that may arise? Read on to learn about zirconia crowns’ disadvantages.
Tooth Reduction
A more aggressive tooth reduction to achieve strength and an aesthetic result could be considered a zirconia crown disadvantage when compared to the minimal reduction of ceramic glass materials, such as lithium disilicate (Emax). Zirconia crowns require a minimal marginal depth of 0.6 mm with axial wall reduction of at least 1.0 mm and an occlusal reduction of 1.5 mm following the original tooth anatomy.
Given these requirements, removal of good tooth structure still remains much more conservative when compared to the requirements for PFM restorations, which must allow for multiple layers of porcelain in addition to a metal substructure.
Aesthetic Concerns
When zirconia crowns were first introduced in 2010, only bone-white substructures could be produced, creating problems when it came to achieving an aesthetically pleasing appearance.
This zirconia crown disadvantage often relegated zirconia’s use to the posterior teeth, where it is less visible. Researchers and manufacturers quickly recognized this zirconia crown disadvantage and sought to address the issue.
Now, newer generations of zirconia materials are pre-shaded and can be fabricated to provide highly aesthetic, lustrous restorations with translucent, refractive, and reflective properties that exceed patient expectations for beauty.
Durability
Its inherent strength could be considered a zirconia crowns problem or a liability in certain situations. Because zirconia bonds so well to the tooth structure and is an excessively hard material, it could prove difficult to remove or cut endodontic access should it become necessary for the tooth to undergo additional therapy. While this scenario doesn’t happen often, it should be a treatment planning consideration.
Cost
Another zirconia crown disadvantage to the patient could be its price point. Zirconia crowns typically command as much or more than other types of dental crowns. The cost of getting a permanent crown, including zirconia, can be higher compared to other types of crowns. Nationwide, zirconia has an average price range between $1,000 to $2,500 per crown, depending on the complexity of the case.
Geographic location can also affect the cost. Additionally, insurance companies often reimburse for services at the cost of a comparable metal or porcelain dental crown, arguing that zirconia is a deluxe or aesthetic service chosen for cosmetic reasons when another, less expensive type of crown will serve the same restorative purpose.
Wear on Opposing Teeth
One often overlooked zirconia crown disadvantage is its potential to cause excessive wear on opposing natural teeth. Due to its hardness, zirconia can be abrasive when in direct contact with enamel, especially if the crown’s surface is not polished properly. Over time, this can lead to accelerated wear of the opposing teeth, which may require additional dental treatments.
Cementation Challenges
While zirconia’s strength is a benefit, specialized primers or adhesive resins are often required to ensure a strong bond between the tooth and the crown, making the procedure technique-sensitive.
Limited Long-Term Research
Long-term research on the zirconia crowns performance and durability is still somewhat limited compared to traditional materials While current studies indicate excellent results, the lack of extensive long-term data leaves some uncertainty regarding their behavior over several decades.
How to Care for Zirconia Crowns
Even the most durable dental materials require proper maintenance. Educating patients to care for their zirconia crowns is essential for prolonging their lifespan and maintaining good oral hygiene
Recommended care tips include:
- Daily brushing and flossing: Use a soft-bristled toothbrush and non-abrasive fluoride toothpaste to avoid damaging the crown’s surface.
- Routine dental visits: Regular exams allow your dentist to monitor the crown’s integrity and ensure it remains properly seated and functional.
- Protective nightguards: For patients with bruxism or jaw clenching habits, a custom night guard can prevent undue stress and wear.
- Avoid hard objects: Refrain from chewing on ice, pens, fingernails, or other non-food items that could compromise the restoration.
With proper care, zirconia crowns can last 15 to 20 years or more, offering both functional and aesthetic benefits that stand the test of time.
Overview of Zirconia Crown Disadvantages
Despite their many advantages, zirconia crowns come with certain drawbacks that should be carefully considered during treatment planning. All of the above factors must be weighed by the dentist and patient when deciding on the best restorative option.
When Is a Zirconia Crown the Best Choice?
While zirconia is one of the most advanced materials available, it’s not the only solution. The choice of material should be guided by clinical needs, patient expectations, and aesthetic goals. In many cases, zirconia offers the best balance of strength and appearance.
Ideal scenarios for choosing zirconia include:
- High-stress areas: Molar and premolar restorations or long-span bridges where strength and durability are desired.
- Bruxism patients: Those who grind or clench their teeth benefit from zirconia’s resistance to fracture.
- Metal sensitivities: Zirconia is 100% metal-free and hypoallergenic, making it a safer option for patients with known allergies.
- Minimal prep cases: When conserving natural tooth structure is a concern, zirconia allows for more conservative preparations than traditional PFM crowns.
Alternative materials may be better for:
- Anterior restorations where translucency is critical: Lithium disilicate (Emax) offers superior aesthetics than zirconia.
- Patients requiring easy access for potential endodontic retreatment: Zirconia can be difficult to remove once bonded.
- Cost-sensitive cases: Porcelain-fused-to-metal (PFM) or full-metal crowns may offer budget-friendly alternatives in certain clinical situations.
How is a Zirconia Dental Crown Created?
Zirconia crowns are made using computer-aided design and manufacturing (CAD/CAM) technology to ensure precise fit, durability, and aesthetics. What exactly goes into making these crowns, and why are they so popular? Let’s get into the details.
The process involves several key steps:
1. Initial Consultation & Tooth Preparation
- Your journey to a zirconia crown starts with a dental consultation.. The dentist evaluates the tooth to determine if a zirconia crown is necessary. Reasons for needing a crown include severe decay, fractures, or after a root canal treatment.
- The affected tooth is shaped and prepared, ensuring there’s enough space for the crown.
- If the tooth is severely damaged, a build-up (core) may be placed before shaping.
2. Digital or Traditional Impression
After preparation, the dentist captures an impression of your tooth and the surrounding teeth. This can be done in two ways: digital or traditional.
- A digital scan (intraoral scanner) or a traditional putty impression is taken of the prepared tooth and surrounding teeth.
- The impression is sent to a dental lab or used in an in-office milling system if the clinic has CAD/CAM technologyOtherwise, the impression is sent to a dental lab for fabrication..
3. CAD/CAM Design
- Once the impression is ready, a dental technician (or in-office software) uses CAD software to create a 3D model of your zirconia crown. This step is crucial for ensuring the crown fits precisely and looks natural. The software allows for adjustments to optimize the shape, size, and bite alignment of the crown
4. Milling the Zirconia Block
A solid zirconia block is placed into a CNC milling machine that carves out the crown with extreme precision. Solid zirconia crowns are known for their durability and high strength, offering long-lasting performance and reduced wear on adjacent teeth. This process can take 15–30 minutes for in-office milling or a few days in a dental lab.
5. Sintering (Strengthening the Zirconia)
- The milled zirconia crown is heated in a sintering furnace at over 1,500°C (2,732°F).
- This process hardens the zirconia, making it exceptionally strong and resistant to wear.
- The sintered zirconia crown is now ready for aesthetic enhancements.
6. Staining & Glazing for Aesthetic Enhancement
- The crown is then custom-stained and glazed to match the patient’s natural teeth.
- Some zirconia crowns are layered with porcelain for enhanced translucency.
- A final polishing step ensures a smooth, natural-looking surface.
7. Final Fit & Cementation
The finished zirconia crown is sent back to the dentist. While waiting for the custom permanent crown to be fabricated, a temporary crown is placed on the prepared tooth as a provisional solution. The dentist checks the fit, shape, and bite alignment with the patient. Once approved, the crown is bonded to the tooth using strong dental cement. The patient receives care instructions for long-term durability.
Are Zirconia Crowns Popular with Dentists and Patients?
Yes, zirconia crowns are highly popular among both dentists and patients due to their exceptional strength, durability, and aesthetic appeal. Below is a breakdown of why they are widely preferred in modern dentistry.
1. Popularity Among Dentists
Durability & Strength:
- Zirconia crowns are extremely strong and resistant to fracture, making them ideal for molars and patients with heavy bite force or bruxism (teeth grinding).
- Made from zirconium dioxide, these crowns benefit from the material’s durability and strength, which are highly valued in dentistry.
- Their high flexural strength (900-1200 MPa) makes them one of the toughest dental materials.
Biocompatibility & Hypoallergenic:
- 100% metal-free, meaning no allergic reactions like those associated with metal or PFM (porcelain-fused-to-metal) crowns.
- Biocompatibility ensures less irritation to gum tissue, making them a safe long-term option.
Minimal Tooth Removal:
- Zirconia crowns require less tooth reduction compared to other crowns, preserving more of the natural tooth structure.
CAD/CAM Technology & Efficiency:
- Many dental practices can mill zirconia crowns in-office using CEREC or other CAD/CAM systems, allowing same-day restorations.
- This reduces multiple appointments and enhances patient convenience.
Versatility:
- Suitable for both front and back teeth when layered with porcelain for a more aesthetic look.
- Can be used for single crowns, bridges, and implant-supported restorations.
2. Popularity Among Patients
Natural-Looking Aesthetics:
- Modern zirconia crowns are more translucent than early versions, making them more lifelike and closely resembling natural teeth.
- Some zirconia crowns are layered with porcelain to further enhance their cosmetic appeal.
Longevity:
- With proper care, zirconia crowns can last 15-20 years or more, significantly outlasting traditional PFM and ceramic crowns.
Stain & Fracture Resistance:
- Highly resistant to chipping, cracking, and staining (unlike porcelain, which can chip over time).
- Great for coffee and tea drinkers since zirconia doesn’t discolor easily.
Same-Day Convenience:
- Many dental offices can offer same-day zirconia crowns, reducing wait times and eliminating the need for temporary crowns.
Common Questions About Zirconia Crowns
Zirconia restorations are a top choice in modern dentistry, but patients and clinicians often have specific questions before committing to treatment. Here are a few of the most commonly asked questions:
Can zirconia crowns be repaired if damaged?
Minor chips or cracks may sometimes be smoothed or repaired with composite resin. However, in most cases, significant damage requires full replacement due to zirconia’s hardness.
Are zirconia crowns safe for patients with metal allergies?
Yes. Zirconia is completely metal-free, making it an excellent choice for patients with sensitivities or allergies to nickel or other metals found in traditional restorations.
How do zirconia crowns compare in cost to other crown types?
Zirconia crowns are typically more expensive than porcelain-fused-to-metal or full metal crowns due to the technology and materials involved. However, their durability and low maintenance can make them more cost-effective in the long term.
Do zirconia crowns stain or discolor over time?
Zirconia is highly stain-resistant, especially when properly glazed and polished. This makes it an excellent choice for patients who consume staining beverages like coffee, tea, or wine.
Do zirconia crowns require special cleaning tools?
No. Patients can clean zirconia crowns just like their natural teeth, using a toothbrush, floss, and routine dental hygiene products. However, using non-abrasive toothpaste is recommended to preserve the crown’s polished surface.
Stomadent Zirconia Creations
Don’t let potential zirconia crowns problems or disadvantages deter you from offering strong and beautiful crown and bridge restorations to your patients. The staff and lab technicians at Stomadent Dental Laboratory got on board with CAD/CAM many years ago, when zirconia crowns were in their infancy.
We have the experience, expertise, and unmatched knowledge of the product to be able to deliver to you precisely-milled crowns of unparalleled lifelike radiance that fit precisely at delivery. Stomadent Dental Lab wants to partner with you to become an extension of your dental practice!