Fixed prosthodontics is a branch of prosthodontics that deals with replacement and / or restoration of teeth with artificial substitutes that are not readily removed from the mouth. In prosthodontics, crown and bridge treatment is referred to as fixed partial denture. Crowns and bridges are the fixed prosthetic substitutes for replacing one or few teeth in the dental arch.
A natural tooth with extensive loss of tooth structure either due to fracture or due to extensive decay needs a protective cover to increase its life; this protective cover is called the dental crown. Crown is also given over the implant abutment to replace the tooth. Bridge is the prosthesis which actually bridges the gap (missing tooth) by taking support from the either side’s natural teeth. Thus whenever you have tooth/teeth missing, the missing area is given an artificial tooth, which takes support from the teeth present adjacent to them.
There are different materials available to fabricate crowns and bridges such as, metals and dental porcelain (ceramics),
Today the evolution of computerized systems, newer techniques and materials have opened new doors for the restorative dentistry by giving optimized properties, such as better strength, appropriate wear behaviour and acceptable aesthetic characteristics. Restorations with newer techniques and materials include – monolithic zirconia restorations; multi-layered dental prostheses, new glass-ceramics, polymer infiltrated ceramics etc.
CAD-CAM technology has provided more precision to the restoration methods. Composite materials processed via CAD-CAM have become an interesting option, as they have intermediate properties between ceramics and polymers and are more easily milled and polished.
What is the procedure?
For receiving a crown, tooth needs to be reduced in size at least 1.5 mm all over. This provides space for an artificial material that covers the underlying tooth. Your dentist will use some instruments called diamond burs, that cut the tooth structure with high speed and the procedure of tooth reduction is completed in a few minutes. After tooth reduction of required size, the impressions are made using the impression materials such as alginate or rubber base materials out of which the models are retrieved. The crown and bridges are fabricated over the models in the dental laboratory.
Types of FPDs
There are varieties of fixed partial dentures are classified as per the coverage and material used –
- Full metal crown
- Porcelain fused to metal crown
- Metal free or all ceramic crowns such as – zirconia, zermac, cerek , IPS empress, E- max etc. porcelain / ceramic are all tooth coloured materials
Bridges can be –
- Adhesive bridges (Mary land bridges)
- Full cover bridges
- partial cover bridges
Most of the people do not like the idea of reducing adjacent sound & healthy teeth. Sometimes even these sound teeth need to undergo intentional root canal treatment to be used as abutment teeth. But many opt this method to replace their missing teeth because it is fixed and more economical than implants.
Another way to replace missing teeth is dental implant supported prosthesis. Implants are commonly used now-a-days and have become a treatment of choice and the most preferred option for the majority who do not want removable teeth.
Post and core treatment to restore RC treated teeth
Endodontically treated teeth require a special treatment to increase their life. After root canal treatment a tooth becomes brittle as it loses tits vitality. Thus it requires a protective cover to increase its life and functionality. Most of the times after RCT, the tooth structure remains so less that your dentist might need to take extra support from the root of your RC treated tooth. This procedure is called post and core treatment where either the metal or fibre reinforced composite light post is used over which the core is built which is used as an abutment to support the crown.
Post and core requires some tooth structure present, if there is extensive loss of it, the post and core can be cast together and customized as per the canal dimensions.