Dental Procedure Blog series
The following series of blogs will cover the different areas of dentistry. The aim is to simplify and explain the jargon that patients encounter in the normal course of dental visit. It is based on the Ontario Dental Association’s procedure categories and descriptions.
Restorative Part 2
Restorative dentistry is the term that describes any procedure that restores a tooth to function and appearance. By this definition fillings, crowns, bridges and implants, dentures fall into the category. However, to keep it simple, the usual meaning is used as it applies to the single tooth.
Restorative treatments can be divided into two categories: basic which includes fillings as discussed in part 1 and major restorations. These include interventions that usually require the services of a dental laboratory to fabricate the restoration.
A core is at the heart or center of something. In the case of a tooth it is the center of a tooth that has lost most of its visible part above the gum line either due to trauma or decay. If the tooth has been root canal treated, then the pulp chamber is empty and requires something to fill it and give the remaining tooth structure strength.
Posts may be used to help retain the core in place.
Cores may be made at the chair side or they may be lab fabricated ones that are cast metal. These are usually in conjunction with posts. Once cemented into place, a crown preparation may be completed if not already a single unit built onto the core.
Crowns or caps are used when there is little natural tooth structure remaining above the gum line or the filling is so large that it will not last long under the forces of chewing and or bruxing. Crowns act like ‘barrel hoops’ at the neck of the tooth to hold the tooth together. They may also be used to improve aesthetic appearance and in rebuilding lost vertical dimension between the upper and lower arches.
Crowns may be all metal (gold, semi-precious alloys), porcelain fused to metal, all porcelain or zirconium with porcelain.
Like crowns, these are made at the lab and are cemented on top of a prepared tooth. They tend not to be more conservative than crowns, meaning there is less tooth structure removed. They too may be made of metal or porcelain.
An inlay is like a filling, but for a number of clinical reasons, is made by the lab and then cemented into place like onlays and crowns. Similarly, they may be of metal, porcelain or composite resin. The choice will be based on functional need and appearance.
Sometimes for conservation of tooth structure the restoration of choice is an inlay-only which is mid way between an inlay and a crown.
Implant supported crowns
In today’s world conservation of tooth structure is the trend. So, if only one tooth is missing, we are loathe to prepare teeth on either side of the space. To replace the missing tooth the most conservative is an implant placed into the jaw. Once the implant has integrated into the bone, a lab fabricated crown is place on top of it. The implant acts like a root. The crown may be cemented or screwed into place. Clinical circumstances will determine the choice.
Veneers are used to improve the appearance of teeth. They may require some tooth preparation or may not, depending on the clinical circumstances. Once the lab has fabricated them out of porcelain, they are bonded to the enamel.
Veneers may also be done at chair side using composite resin filling materials. There will be a financial or clinical reason for the choice of material.
On some occasions, the dentist may have a CAD-CAM machine in the office and can produce the crowns, inlays or veneers from porcelain on the same day. This approach leaves out a second appointment and the laboratory.