Porcelain fused to metal dental crown (PFM)
Porcelain fused to metal crown (PFM) is a full cast crown that is constructed by fusing the porcelain to all or most of the metal surfaces.
Indications of porcelain fused to metal crown
A PFM dental crown is indicated in case of minimal inter-occlusal clearance that requires a stronger restoration. It is also used on any tooth that requires a full crown for preventive and restorative purposes.
Contraindications of PFM dental crown
PFM dental crown is contraindicated when the size of the tooth pulp is negligibly smaller thus compromising the tooth preparation process. It is also contraindicated when the clinical tooth crown is very short and lacks the required stability including retention that is enough to provide the space for porcelain and metal.
Advantages of PFM dental crown
The major advantage of PFM crown is its metal substructure that provides adequate strength.
Disadvantages of PFM crown
PFM crown requires removal of 1.5 mm of buccal tooth substance to place the porcelain and metal layers. It lacks esthetic look due to its opaque metal layer. An e-max or a zirconium crown can be a best option when one is looking for an aesthetic appearing tooth crown.
The E-Max dental crown is considered to be a best inclusion in dental crown technology. It is a form of all-ceramic crown which provides best aesthetic appearance by complimenting with the natural teeth and it lasts longer. It has an appealing translucent color and is highly durable with extra strength.
Emax crown is generally constructed by 4 techniques: Pressed, milled Yttrium Zirconia, pressed to Zirconia, and a milled esthetic glass.
Indications of E-Max crown
E-max crown is indicated for stained or damaged teeth with poor quality and to provide an aesthetic look.The E-max crown consists of a block of top grade material, lithium di-silicate ceramic which assures correct fitting, durability, toughness, and opaqueness thus it is priced more. The crown is also made of a glass ceramic crown that is endurable with a higher toughness but still providing a delicate look.
Advantages of E-max crown
The E-max crown has a lifelike shape and transparent color that provides an exact color match with the patient’s own natural teeth. It has no metal alloy base thus does not affect the aesthetics around the gum line. The crown is long lasting, strong, and less prone to fractures when compared to other traditional crown types. When compared to zirconia crowns, an E-Max crown is less likely to get chipped.
Disadvantages of E-max crown
The only disadvantage of E-max crown is its high cost especially during tooth preparation. It requires a premium crown placement without tooth preparation and hence it is more expensive when compared to its other crown counterparts. In addition, e-max crown is not suitable for all patients and one should discuss it with dentist about availability and whether it is the appropriate one.
A zirconia crown is made of a strong, biocompatible material, zirconia which is also used in medical applications like artificial joints. It is a well-known, type of all-ceramic crown which significantly improves the tooth appearance that has been previously disfigured or stained for years.
Different types of zirconium dental crowns include:
- glass-infiltrated zirconium toughened alumina (InCeram Zirconia)
- yttrium cation-doped tetragonal zirconia polycrystals (Cercon Zirconia)
- partially stabilized zirconium (Mg-PSZ)
- shrinkage free ZrSiO4 ceramic
- Cercon Base ZrO2 sintered crown
Advantages of zirconia crown
Zirconia is a crystal form that is indestructible and lasts longer. It has adequate strength and durability. In fact, its crown cannot be spotted amongst natural teeth. Patients are least likely to develop an allergic reaction to zirconia and thus considered a safe option when compared to porcelain fused to metal crowns.
Zirconia crown is long lasting, easy to wear and durable when compared to other crowns. The translucent appearance of zirconia crowns blends well with the natural teeth color and thus provides the most pleasing appearance. It requires minimal tooth preparation thus preserves most of the original tooth substance which is also favorable while removing the crown. Hence, zirconia crown is an ideal option to cover-up the damage including stains and to restore the tooth function.
Disadvantages of zirconia crown
The zirconia crown is tough, durable and possesses abrasive quality thus imposing the friction against the tooth root including neighboring teeth. Hence, an E-max crown could be a favorable option for cases that require preservation of the root structure.