When it comes to choosing the right material for dental crowns, durability and strength are key factors to consider. Two popular options in the field of cosmetic dentistry are Emax (lithium disilicate) and layered zirconia. While both materials have their own unique advantages, it is important to understand their differences in order to make an informed decision. In this article, we will explore ten aspects to compare the strength of Emax and layered zirconia for dental crowns.
1. Material Composition
Emax crowns are made from lithium disilicate, a glass-ceramic material that is known for its excellent aesthetics and strength. Layered zirconia, on the other hand, is composed of a zirconia core covered with layers of ceramic to improve its appearance. The difference in material composition can impact the strength of the dental crown.
Emax provides a high level of strength due to its densely packed lithium disilicate crystals. The layered zirconia crowns also offer good strength since zirconia is an incredibly strong material. However, the layering process may slightly decrease its overall strength compared to Emax.
Overall, both Emax and layered zirconia offer satisfactory strength for dental crowns, but Emax may have a slight advantage in terms of material composition.
2. Flexural Strength
Flexural strength, which measures a material's ability to resist bending and breaking, is another important factor to consider when comparing Emax and layered zirconia.
Emax crowns have an impressive flexural strength ranging from 360 to 400 MPa, making them highly resistant to fracture. On the other hand, layered zirconia crowns typically have a flexural strength of 900 to 1200 MPa, making them even stronger in this aspect. This higher flexural strength of layered zirconia makes it an excellent choice for patients with bruxism or other significant biting forces.
Based on flexural strength alone, layered zirconia appears to be the stronger option.
3. Esthetics
While strength is essential, the esthetic appeal of a dental crown is equally important. Emax crowns are known for their high translucency, mimicking the appearance of natural teeth more accurately than layered zirconia.
Layered zirconia crowns, on the other hand, provide strength and good aesthetics due to the presence of layered ceramic. However, its opacity can sometimes result in a less natural look, especially in thinner or more translucent areas where the metal core may be slightly visible.
Although layered zirconia offers decent esthetics, Emax is often considered the superior choice for patients who prioritize a natural look.
4. Durability
In terms of durability, both Emax and layered zirconia are highly resistant to wear and fracture. However, Emax is more prone to chipping or cracking under extreme biting forces compared to layered zirconia.
Layered zirconia, due to its exceptional strength, provides excellent durability and is less likely to chip or crack even in harsh conditions. This increased durability makes layered zirconia an ideal choice for patients who require crowns in areas subjected to high chewing forces.
Although Emax is generally durable, layered zirconia is considered the more robust option in terms of longevity.
5. Biocompatibility
Biocompatibility refers to the material's ability to be compatible with the oral tissues and the human body in general. Both Emax and layered zirconia demonstrate high biocompatibility, making them safe choices for dental restorations.
Emax is known for its excellent biocompatibility, with no reported cases of adverse reactions. Layered zirconia, although composed of zirconia, a bioinert material, may cause minimal allergic reactions in rare cases due to the presence of other components in the ceramic layers.
Overall, both materials are considered highly biocompatible, but Emax has a slightly better track record in this aspect.
6. Cost
Cost is an important consideration for many patients when selecting dental crowns. The price of Emax crowns varies depending on factors like the dental office location, complexity of the case, and the expertise of the dentist.
On average, Emax crowns can cost between $800 and $1500 per tooth. Layered zirconia crowns, due to their higher material and production costs, are typically more expensive than Emax crowns, ranging from $1000 to $2000 per tooth.
It is crucial to consult with your dentist regarding the cost of each option, as prices may vary.
7. Preparation Requirements
Both Emax and layered zirconia dental crowns require similar preparation processes. However, due to the material's strength, layered zirconia may require more tooth reduction compared to Emax crowns.
Emax, being relatively stronger than traditional porcelain, may allow for more conservative tooth preparations, preserving more natural tooth structure. Layered zirconia, due to its inherent strength, provides a suitable alternative for cases where more tooth reduction is required.
It's essential to discuss the preparation requirements with your dentist to determine the best choice for your specific oral condition.
8. Longevity
Both Emax and layered zirconia crowns offer excellent longevity when properly cared for. With good oral hygiene practices and regular dental check-ups, both materials can last for many years.
Emax crowns have an average lifespan of 10 to 15 years, while layered zirconia crowns can last 15 to 20 years or more. However, it's worth noting that individual factors such as oral hygiene, bite forces, and tooth preparation can influence the lifespan of the crown.
In terms of longevity, layered zirconia has a slight advantage over Emax crowns.
9. Repair and Maintenance
If a crown gets damaged or requires repair, both Emax and layered zirconia can be repaired using composite resin. However, Emax crowns may be easier to repair due to their composition and the availability of specific repair kits.
Both materials require regular maintenance, including proper oral hygiene practices and routine dental visits. Avoiding excessive biting forces on the crown and refraining from habits like chewing on hard objects can help prolong the life of the restoration, regardless of the material chosen.
10. Dentist's Recommendation
Ultimately, the decision between Emax and layered zirconia should be made in consultation with your dentist. The dentist will consider various factors such as your oral health, bite forces, aesthetic preferences, and budget to recommend the most suitable option.
It's essential to find a qualified and experienced dentist who can provide personalized advice based on your specific needs.
Frequently Asked Questions (FAQs)
Q1: Which is stronger, Emax or layered zirconia crowns?
A1: Layered zirconia is generally considered stronger than Emax crowns due to its higher flexural strength. However, both materials provide satisfactory strength for dental crowns.
Q2: Are Emax crowns more expensive than layered zirconia crowns?
A2: On average, Emax crowns are slightly less expensive than layered zirconia crowns. The cost may vary depending on factors such as the location of the dental office and the complexity of the case.
Q3: Can Emax and layered zirconia crowns be repaired?
A3: Yes, both Emax and layered zirconia crowns can be repaired using composite resin. However, the ease of repair may vary slightly, with Emax crowns generally considered easier to repair.
References:
- Mafi P, Ojaghi R, Paknejad M, et al. Lithium disilicate prosthetic restorative materials: a review of the literature. J Clin Exp Dent. 2019;11(11):e1050–e1057.
- Shenoy A. Zirconia in dentistry: a review. J Int Soc Prev Community Dent. 2019;9(2):97–103.
- Li R, Sun L, Ren Y, et al. The clinical evaluations of lithium disilicate all-ceramic crowns in the premolars of the Chinese population: 5-year follow-up. Ann Transl Med. 2018;6(14):272.
- Sivaharan V, Matthews S, Antony A. Strength properties of porcelain veneers luted with different adhesive resins. J Conserv Dent. 2017;20(3):160–164.
