Caps, Crowns & Bridges
The common dental treatments used to restore or improve the appearance and function of teeth.
What is a crown?
A crown is a word for the prosthetic replacement of all of the surface of a tooth that is visibly seen. A term that the public often uses for this is a cap. An older term that is still sometimes heard is a jacket.
What is a bridge?
A bridge is commonly used to define the replacement of a missing tooth or teeth by suspending the missing tooth replacement off a crown on the teeth to either side of the missing tooth space. The artificial tooth is called a pontic (as in pontoon) and the teeth which carry the crowns are called abutments.
Technically this prosthesis is a fixed partial denture, a term mostly reserved for proper correspondence between professionals. A bridge can also refer to the same design concept with dental implants being used instead of teeth. The public may use the term bridge when they are referring to a removable device which replaces some missing teeth — what dentists would call a removable partial denture.
Conventional techniques require the tooth to be prepared and an impression made of that preparation from which the dental piece will be made in the lab. The patient leaves with a provisional or temporary piece in place and returns at a later date for the delivery of the definitive piece. In most cases now, a computer can generate a crown from a scan of the prepared tooth while the patient waits.
What is an inlay?
An inlay is like a filling, only it’s made in a laboratory like a crown. Technically it is placed into the tooth rather than covering over the tooth. Since there has to be a slight taper like a cork shape, a dentist would have concerns about placing inlays in some teeth. I feel that biting forces tend to make inlay’s crack teeth.
What is an onlay?
An onlay is essentially a crown that does not completely cover the sides of a tooth. They have advantage over an inlay because they cover the cusps of the tooth and help prevent teeth from cracking.
What is a veneer?
A veneer is a thin shell of material which typically covers the visible portion of front teeth. They are usually used for cosmetic improvements such as color change and slight alteration in the shape, size and position of teeth. Veneers can also be placed over chipped or broken teeth and over some fillings in teeth. They are bonded to the tooth with an extremely strong resin.
Materials
Crowns and bridges can be made of metal, porcelain, or plastic or a combination of metal and porcelain or plastic. The metal components are important for their physical properties. Dentists use the finest of alloys which contain gold, platinum, and palladium as the main components. They select different alloy composition as needed for strength relative to span and abutment design. They fire porcelain to this metal and these are then referred to as PFM’s or porcelain fused to metal crowns or bridges.
Inlays, onlays, and some crowns used to be primarily gold. Today this is not so popular because of the esthetics. Newer materials and techniques have given us composite resin or porcelain inlays and onlays and crowns.