Dental crowns, also known as “caps,” preserve the functionality of damaged teeth. Crowns may be used to protect a cracked tooth, restore the function of a tooth with an extensive filling, or replace a pre-existing crown. The purpose of a dental crown is to encase a needy tooth with a custom-designed material. Dentists today have a variety of conservative treatment options through which to restore teeth. If possible, these options should be explored and discussed before selecting the full coverage crown.
Why do I need a crown?
If you want your smile to be your crowning glory, you need healthy, attractive teeth. When they are cracked, stained or damaged, however, your teeth detract from your dental health and appearance. To restore them, we may recommend crowns. The following will help answer some of the common questions you may have about crowns.
What are crowns and why are they used?
A crown is a restoration that covers or caps a tooth to restore it to its normal shape and size. Its purpose is to strengthen and/or improve the appearance of a tooth. A crown is placed for a number of reasons:
- To support a large filling when there isn’t enough tooth remaining
- To attach a bridge
- To protect weak teeth from fracturing
- To restore fractured teeth
- To cover badly shaped or discoloured teeth
- To cover a dental implant
Materials for crowns and bridges
The four predominant choices of restorative materials for the full coverage crowns are:
- Resin Crowns (PMMA)
- Porcelain-fused-to-metal (PFM)
- All-ceramic (all-porcelain): Emax, Zirconia
The material selected is determined by the clinical demands at hand; aesthetic demands, strength requirements, material durability and restorative space available.
Different types of crowns
Resin crowns are laboratory fabricated crowns from resin, which is the same material dentists use to fill a tooth. Resin crowns offer a beautiful aesthetic result at half the price of porcelain crowns. Resin crowns are an excellent short-medium term result (3-5 years), after which they tend to stain and sometimes chip. Resin crowns are a good alternative for those whom are price conscious or are unsure as to the exact colour and contour of the look they wish. (see Barry Coogan Nikon photo’s).
Porcelain-fused-to-metal crowns provide for a strong, durable, and aesthetic treatment option. One of the key factors for the aesthetic and functional success of this type of crown is ensuring the preparation of the underlying tooth structure provides adequate space for the appropriate thickness of the material selected. Additionally, the artistic skill of the laboratory technologist creating the crown will determine its aesthetic appeal.
One consideration in the porcelain-fused-to-metal crown is that these crowns may tend to show the underlying metal or gold margin at the gum line as gums recede over time. Some patients opt for this type of crown, but replace the crown at a later date in order to maintain a higher aesthetic benefit. Porcelain-fused-to-metal crowns with an all porcelain collar can eliminate this vulnerability.
All-ceramic crowns (Emax and Zirconia)
The predominant material choice for all-ceramic crowns today is either zirconia, or aluminous materials. They provide a metal-free aesthetic option with a number of benefits.
By eliminating the need for the supportive metal core, an aesthetic all-ceramic crown can be created with a reduced thickness of material. This makes them a more favourable treatment choice in areas with limited space. Additionally, the elimination of the metal core allows for light transmission through the porcelain for better optical, life-like properties and a higher level of aesthetics.
All-ceramic materials continue to evolve in strength and durability, but caution should still be exercised for areas of the mouth requiring heavy function.
Although not as popular a treatment choice for aesthetic reasons, gold crowns are still indicated in some instances. For example, patients with strong bites and those with parafunctional habits (such as grinding or clenching) might be better served with gold crown. The traditional restorative material can provide stronger support to the remaining healthy tooth structure. Gold crowns offer a level of durability that is appropriate for teeth located in the back of the mouth (such as the molars), where they will not be highly visible. Gold crowns tend to offer greater longevity and require less preparation than porcelain and porcelain-fused-to-metal crowns. When chewing, gold tends to be less abrasive to the opposing tooth than porcelain. This helps to prevent wearing of the teeth.
The crown procedure
At the initial appointment with the dentist, they will evaluate the tooth which requires a crown. They will take a photo and x-ray of the tooth, then explain to you why the tooth requires a crown and any risks they may foresee. From there you will be provided with a quote from which you can contact your health fund and enquire if you are eligible for a rebate on the procedure.
At the next appointment, you will be anaesthetised by local anaesthetic and the tooth is prepared once you are numb by removing the existing filling and shaving the tooth by 2mm in all surfaces. Once the preparation is complete, the dentist may take another photo of the tooth to show any cracks. An impression is then taken and sent to the dental laboratory to fabricate the crown especially for you and your bite. A temporary crown is then placed on top of the prepared tooth, to protect it from sensitivity and bacteria.
At the final appointment, the temporary crown is removed, the tooth cleaned and the final crown cemented onto the prepared tooth. The bite is then checked and you are right to go!
How long do crowns last?
This will depend largely on how well you look after your teeth. Dental crowns require the same level of care and attention as your natural teeth. Provided you have a good oral hygiene program and attend regular check and cleans at the dentist and do not suffer from teeth grinding, maintain a tooth-kind diet and do not do things like open beer bottles with your teeth then a high quality dental crown can last 10-15 years. At Budi Dental our crowns and bridges are 100% Australian made. We have full confidence in our products such that we provide a 5 year warranty (Terms and Conditions apply).
Risks of having a crown
Sometimes a tooth reacts to having the preparation done, which can lead to ongoing sensitivity generally to cold substances. This is most cases resolves in a few weeks with the use of a sensitive toothpaste. In 10% of cases it does not resolve and may in fact become worse. In this instance the tooth will require root canal treatment. Some people find the shape and size of a crown different to what their original tooth was like. In most cases the crown feels just like their natural tooth in a few weeks, but sometimes an adjustment of the crown is required.
One or more missing teeth can adversely affect the appearance and functionality of your smile. Missing teeth can cause a change in occlusion (bite), shifting of the teeth, temporomandibular joint disorder, speech impediments, an increased risk for periodontal disease and a greater chance of tooth decay.
Dental bridges, like implants and partial dentures, are used to replace missing teeth. There are several types of fixed dental bridges (cannot be removed), including conventional fixed bridges, cantilever bridges and resin-bonded bridges.
Typically, conventional and cantilever bridges require shaping of the teeth surrounding a missing tooth. Crowns are then placed on the shaped teeth and attached to an artificial tooth (called a pontic).
A resin-bonded bridge requires less preparation of adjacent teeth. It is often used to replace front teeth, provided that the gums are healthy and the surrounding teeth do not have extensive dental fillings.
The dental bridge procedure
During the first visit, the dentist examines the health of your gums and other teeth to evaluate if you are a candidate for a dental bridge. If you are a candidate for a dental bridge, you are given a local anaesthetic so the dentist can prepare the teeth required to support the bridge. If the support teeth are decayed or badly broken down, the dentist may have to build them back up before they can be used as support teeth for a bridge.
Next, the dentist takes an impression of the prepared teeth with a putty-like material that is used to create a model of your teeth. Your bridge is fabricated based on this model by a skilled lab technician so that it precisely fits the prepared teeth. It is important that your restoration fit perfectly to avoid additional oral health problems such as tooth decay.
While your bridge is being fabricated, the dentist fits you with a temporary bridge so the teeth and gums can be protected from damage until your permanent bridge is ready. To complete the dental bridge procedure, you must return to the dental office for a second visit to have the bridge fitted and cemented.
In dentistry, a veneer is a thin layer of material placed over a tooth, either to improve the aesthetics of a tooth or to protect the tooth’s surface from damage. There are two main types of material used to fabricate a veneer: composite material and dental porcelain. A composite veneer may be directly placed (built-up in the mouth), or indirectly fabricated by a dental technician in a dental laboratory, and later bonded to the tooth.