Crowns and bridges are prosthetic replacements for natural teeth or a missing tooth, or teeth. They are fixed and cannot be removed from the mouth. It lasts for 10 plus years and behaves in a similar way to the natural teeth.
Crowns can be placed on a natural damaged tooth, over an existing tooth to support a bridge, or on an implant that replaces a natural tooth.
A bridge has two or more crowns joined together, again either on natural damaged teeth or on implants. Bridges are designed as units of two or more teeth. The supporting teeth are called the abutments and the missing teeth that are replaced are called the pontic.
When do Crowns become the Choice of Treatment?
- If a tooth is chipped or fractured and a filling will become so large it will break easily.
- When the carious lesion of a tooth is very deep and a large amount of tooth is lost as the decayed tissue is removed. In these cases, a crown can be a better option as it not only replaces the missing tooth material it also strengthens and protects the tooth.
- After a root canal a crown is placed on the tooth to protect the tooth from cracking and breaking exposing the root canal treatment.
- When an existing restoration repeatedly fractures under heavy biting forces. A crown can last longer than a large filling with heavy bite loads.
When do Bridges become the Choice of Treatment?
- If there is a missing tooth or missing teeth and an implant or partial denture is not desired or not possible then a bridge is a comfortable fixed option.
- If a partial denture that replaces missing teeth is no longer desired, the option is a bridge or an implant.
The Advantages of Crowns and Bridges:
- A crown covers the tooth’s biting surface and can help prevent further degeneration of the tooth and protect against the tooth breaking.
- Functionally a crown or bridge resembles the natural bite pattern and structure. This makes the process of eating more natural.
- The more natural biting patterns help maintain the supporting tissue.
- A balanced chewing process can help to keep the jaw joint (temporomandibular joint) healthy.
- The use of crowns or bridges prevents the neighbouring teeth from drifting and the opposing teeth from over erupting.
- Aesthetics are maintained as both the teeth alignment and facial contours are supported.
- Adapting to the new crown or bridge is easier as it is fixed and not removable and won’t move around in the mouth.
- It lasts for 10 plus years
- Maintenance is easier as all it requires is normal oral hygiene routines.
What are the Steps to make a Crown or Bridge?
- A preliminary analysis of the health of the bone and supporting tooth is completed after a consultation and X-rays are taken.
- The tooth is then prepared, by removing any decayed tooth and reshaping the tooth to a slightly smaller size so the crown can fit on top.
- An impressions of the prepared tooth is taken as well as a replica of how your teeth bite together – this is then sent to the laboratory for the fabrication of a crown.
- A temporary crown is placed to protect the prepared tooth while the new crown is made.
- Once the crown is fabricated, the temporary crown is replaced with the permanent crown.
- This procedure is also replicated when making a bridge.
A Bridge that Replaces Missing Teeth can be Designed in a Number of Ways:
Traditional: A false crown is attached and suspended between supporting natural teeth using crowns placed on these natural teeth.
Cantilever: When the false crown is held by only one natural tooth using a crown placed on this natural tooth.
Maryland: When the false crown is held by one natural tooth by a framework that only bonds to the back of the natural support tooth. This framework could be either metal or ceramic.
Implant supported bridges: Used when the false crown is supported off implants when there are minimal or no natural teeth available.
Choice of Materials for Crowns and Bridges:
Various materials such as gold, porcelain, alloys and acrylics are used to fabricate crowns and bridges. Which material is best for your mouth and your situation can vary. This decision is made after consultation with your dentist and the dental laboratory. It also considers your cosmetic preferences such as white or gold and the amount of strength required due to the functional load placed on the crown when you chew or bite .
Zirconia: This is strong and natural looking and ideal for heavy load areas.
Lithium Disilicate: This is the most aesthetic of materials making it ideal for anterior cosmetic areas but should only be used cautiously in heavy load bearing areas.
Gold: This is the most problem free material due to strength, and longevity. It will not fracture or chip as there is no porcelain which makes it ideal for heavy grinders.
Porcelain fused to Metal: This is the traditional crown that has largely been replaced by other materials. It is made from gold/metal alloy with porcelain fused to the crown. Sometimes the metal under layer can create a dark line around the base of the crown which causes a poor cosmetic end result. The porcelain may also chip from the metal. However, it does still have its place in dentistry and has an evidence based history of success.
Stainless steel: These crowns are used in children to protect badly decayed baby teeth and adult teeth during development and growth of the child. If placed on adult teeth they will require removal and a replacement with an adult alternative once the child is over 25 years.
As with all dental work, crowns and bridges require good oral hygiene with regular brushing and flossing. Regular dental checks are also required to ensure no decay forms around and under the crown. If well cared for, crowns and bridges will offer many years of comfortable service.
Call or Book Today to find out if a crown or bridge is suitable for you.