Dental Crowns are the most modern and effective solution to many of the dental problems that patients face currently. Most patients have a loose or a weakened tooth, either due to an infection, or broken off due to instability or cracks. Dental crowns can also be a result of having to replace your tooth after a root canal treatment done in your teeth. Dental crowns are made from a variety of materials and can easily be made to fit the patients requirements on the basis of size, bite, durability, quality and aesthetic qualities. Dental crowns are technically quite durable and the most preferred procedure to solve most of the modern day teeth concerns by dentists and specialists.
Anterior and Posterior Crowns
When it comes to Dental crowns, they are categorised based on functionality, position of the crown, material used for the crown and the durability of the crown. The most common types of crown types are those based on the material of the crown chosen. Anterior and Posterior crowns are another type of differentiation based on the position of the dental crown fitment.
Anterior Crowns are the crowns that are made in the anterior section of the jawline, which are the primary teeth that are visible when you smile and talk. The predominance of bite and strength is less in the teeth whereas the predominance of appearance and durability is higher. Most people who get an anterior crown done need the crowns to look extremely similar to their original teeth and have minimal to no distraction such as having metal or discolored material for the teeth.
Posterior crowns are made on the posterior end of the teeth. These are the more common types of crowns that are done by dentists as usually, the teeth in the back are the ones who take the maximum damage in terms of cavity and other damages. Therefore the posterior crowns are a more common type of crowns made by dental labs. When it comes to posterior crowns, there is more predominance placed on the strength, durability, bite force etc than the appearance and material used. This is because posterior crowns are not very visible from the outside and can be chosen based on the actual requirements of the patient and aesthetic factors can take a back seat.
Materials used for making Posterior Crowns
Posterior Crowns are made from a variety of materials and the list is ever expanding. With the advancement in dental surgery and dentistry there are many kinds of materials that dentists and labs are experimenting with to create crowns based on following factors:
One of the most important factors when it comes to crowns is their appearance. More and more patients want their crowns, be it anterior or posterior crowns to look as close to natural teeth as possible. This is why this factor has now become one of the most important factor to conduct research and experimentation on many kinds of materials for crowns
Strength and Bite Force
Strength of the crown is another important factor. Most crowns are designated a particular bite force that it can handle based on the position of the crown. For example - posterior crowns tend to take on a lot more bite force and strength than anterior crowns.
Durability is important for a crown as it is a big investment on the part of the patient. Therefore durability and replacement of crown are factors that patients tend to lean towards when opting for a particular material to make their crowns
Dental crowns can be quite an invasive procedure that requires multiple seatings and a considerable investment for your dental health. Dental crowns that are costly may be once in a long time investment but this is a decision factor that most patients need to look into.
Types of Posterior Crowns
Here is the list of types of posterior crowns which you should know while replacing the crowns for you.
Porcelain Fused To Metal (PFM)
Porcelain Fused to Metal is the most recommended and one of the highest used materials in the dentistry world. Porcelain is used for the posterior three quarter crown and the base of this crown is a metal fused to the porcelain part. There are many benefits to having posterior crowns made from Porcelain fused to metal. Some of the best ones are listed here:
Porcelain Fused to metal has more strength than porcelain crowns as such. All porcelain crowns need repetitive changes and maintenance whereas porcelain fused to metal is much more sturdy and has a good strength and can handle better bite force. It is recommended for posterior crowns as they are visibly just like natural teeth but with just a metal lining in the bottom.
Porcelain crowns are very aesthetically pleasing. They have a metal base in the bottom which is a better option if they are posterior crowns. All porcelain crowns are better pleasing for anterior crowns whereas for posterior crowns Porcelain Fused to Metal crowns are a better option
Porcelain Fused to metal crowns are more durable as they have stronger force and can handle down better bite force. They have a long lifespan, much longer than zirconia, all porcelain and other such materials and hardly need any maintenance.
Cast Gold Alloy
Cast Gold Alloy is probably the most retro form of dental crown but they are extremely sturdy and strong. They are an excellent choice for a posterior crown as they are hardly visible during regular activities such as talking and smiling. They also have a better bite down force and therefore can have immense durability and last for over 20 years with minimum maintenance.
The disadvantages of having a metal alloy such as gold is only aesthetic and cost wise. They are a bit expensive and can be quite an investment but will last you for a long time and need little to no maintenance. They are also aesthetically not very pleasing as they clearly look like a dental crown and can be visible upon examination. But for a posterior crown, they are perfect as they wont be immediately visible during regular activities
The advantages of Cast Alloy Crown are mentioned below:
- They are extremely strong and sturdy
- Can handle good bite force for posterior chewing
- Have very less maintenance issues
- Can last for as long as 20 years.
Zirconia is a modern day popular option for dental crowns. They are extremely easy to fit and create custom solutions for patients. They are considered to be one of the best modern day options that trumps options such as cast gold alloy for its price and aesthetics. It can also prove better than ceramic restorations as they are sturdier and have better durability than ceramic crowns. Also, they can be custom created to suit individual requirements and can be color matched with the existing set of teeth.
There are many kinds of Zirconia crowns in the market and it is one of the ever expanding range of options based on appearance, cost and strength. Some of the most popular options are listed below:
- Solid Zirconia
- Bruxzir Zirconia
- 1st Gen to 7th Gen Zirconia
- Veneered Full Strength Zirconia
Zirconia has a better soft-tissue response rate than most of its competitors. This makes it a better choice for a posterior crown. It is surveyed to be one of the best options when it comes to causing allergic reactions, does not wear dentitions, causes gingival irritation or any of such problems associated with metal crowns. In fact, the newer forms of Zirconia restorations look more and more like natural teeth than any other kind of dental restoration material.
Zirconia has its limitations as well with regards to its creation, making of the crown, difficulty in color matching with natural teeth and the overall expenditure in the process. Often the amount of varieties within zirconia restoration can be confusing to dentists as to what options can be offered to the patients. They are not as sturdy as metal fused crowns or cast alloy crowns and have to be replaced every 10 to 15 years - which is nominal given they are cheaper than cast gold alloy crowns. They also are not as sturdy as metal crowns and can have a long breaking in period and may develop cracks if not taken care of properly. They have a decent bite force and strength but they are still being improved and researched.
This type of material is quite new to the market as well. They are quite popular for anterior crowns rather than posterior crowns because of their aesthetic beauty. They are quite undistinguishable when it comes to their colour and texture. They are excellent for premolars and other anterior options and can be one of the best options for the younger kids and young adults who need natural options.
The problem with IPS e.max is the fact that they are not strong enough such as Porcelain fused to metal options or even full strength zirconia restorations. They can also not be recommended for patients who have bruxism - a condition in which the patient grinds on their teeth unconsciously at night. Such severe stress can cause damage to IPS based restorations. Research is still ongoing for this kind of restoration in the market and more and more restorations are being studied to enhance its strength while retaining its aesthetic appeal and similarity.
How often does one need to change their Posterior Crowns?
Crowns can have a lifetime no matter how well you take care of them. In fact poor oral care and hygiene can significantly drop the chances for a long life for the crowns - be it anterior or posterior crowns. Crowns need replacement for a variety of reasons such as:
When a Crown gets worn off
Crowns can get worn off over a period of time due to excessive usage such as chewing and regular eating habits. Every kind of crown material has a lifespan such as the metal based crowns can last upto 15 years whereas Gold alloys can last upto 20 years. Other zirconia and ceramic based crowns can last anywhere between 5 to 15 years based on its sturdity.
When Oral Hygiene causes an issue
One of the biggest issues when a crown would need replacement is when the patient does not take care of the crown. Oral hygiene is extremely important to take good care of the teeth and the crown. Infection in the gums due to plaque accumulation can also creep into the base of the crown and cause root infection and decay inside the crown. Such a situation may call for an emergency tooth extraction
Recession of Gum Tissues
Over time, the gums around the crown placement can recede and cause the fitment to lose its hold. It can also expose the roots to infection. This is why regular dental check up and good oral care is required to ensure that both the crown and the gums around the crown are in good shape.
Bruxism is a practise in many kids and young adults, even in some older adults, where the patient subconsciously keeps grinding together his/her teeth which places a lot of stress on the teeth and especially on the crown. It can wear down the crown very easily causing a lot of damage on the crown and can also pose a challenge for the rest of the teeth. In most cases, the dentist may try to offer solutions to control the bruxism as that is the only way to help retain the crown in such cases.
Malocclusion is a natural tendency of the jaw lines to not be in sync with each other, meaning that they do not fit perfectly together. This in turn may give rise to bruxism as well. The result of this case is that there is uneven pressure on the teeth when chewing or during day to day activities causing uneven pressure on the teeth. This misalignment can cause the crown to wear off faster than usual. Dentists usually recommend fixing malocclusion with one or more procedures to correct the issue alongside the crown treatment as that is the only way to help the crowns from staying in place and from not wearing off too soon.
These are some of the insights on Posterior crowns and the types of posterior crowns that are available in the market. Ensuring good dental and oral care and visiting your dentist regularly can help you in keeping up with the dental and oral health and to get the best guidance on modern day options for your dental requirements.