Crowns & Bridges are the two ways to repair or replace the missing teeth.
Crown or a ‘cap’ is a restoration that is used to replace a single tooth. A series of crowns can be used to replace several teeth. The Crown can be made to fit over an existing tooth or can be attached to a dental implant. A crown (or cap) completely covers a damaged tooth to restore it to its normal size and shape.
Crowns are often recommended in conjunction with root canal treatment, as the tooth tends to become brittle and is more likely to fracture. Crowns strengthen and protect the remaining tooth structure and improve the appearance of your teeth.
Crowns are used to restore both anterior and posterior teeth that have been broken or are at high risk of doing so due to over-sized old fillings or fractures.
Before a dental crown can be placed the tooth must first be trimmed so it is tapered in shape. This tapered aspect of the tooth will extend up into the dental crown’s center and is a very important factor in the crown’s stability. After the needed shape has been achieved your dentist will take an impression of the tooth, which in turn is sent to a dental laboratory, which will create the crown. Once the dental lab has completed your crown your dentist will cement it in place.
Cavities (decay, Dental caries) start mainly as a result of bacterial action on the food particles that stick to teeth. Certain types of bacteria break down these food particles, producing acidic substances, which erode the enamel of the teeth and roughen it. The enamel is made up of calcium compounds mostly) More food particles stick to these roughened areas which get colonized by the bacteria, eroding the enamel and then the second layer, dentine.
Tooth decay or caries usually starts on the crown and the filling or restoration is limited to the crown if the decay has not reached the pulp. Once the decay (and bacteria) get into the pulp, the root canal has to be cleaned, disinfected and filled. This may require one or many sittings depending on whether the infection is limited to the root canal or if it has spread into the bone, beyond the root canal.
Silver amalgam (a mixture of mainly silver and mercury), composite resins, Glass ionomers etc are some of the main materials used for restoring decayed teeth. Metals and ceramic, prepared to the exact dimensions of the cavity also are used.
Bridge is a way to replace one or more missing teeth and is permanently fixed in your mouth. Spaces left by missing teeth affect the rest of your teeth. Replacement of missing teeth makes it easier to chew, improves your appearance and also keeps your teeth, gums and jaws healthy. Even if only one tooth is out of place other teeth may slowly shift, in turn changing the way your teeth meet (your bite).
The maximum number of teeth that can be replaced by a bridge is two to three. Much depends upon the health of the remaining teeth and in which area the teeth are missing. Bridges are fixed on non-removable prosthesis constructed to replace one or more missing teeth. The teeth on either side of the existing space are used to anchor the bridge to restore functionality as well as aesthetics.
Beautiful porcelain over metal bridges as well as full porcelain and resin-based bridges are available producing the best results depending on the particular situation and requirement.
The missing tooth in the above pictures could be replaced with a bridge. The teeth either side of the gap are prepared for crowns that will support a bridge across the gap. Here, the finished bridge has been placed in the mouth using permanent glue.
Unlike a normal bridge that is attached to teeth on both sides, a cantilever bridge is one that is attached only on one side to the remaining teeth. The other side is free or unattached. These cantilever bridges are indicated when the tooth to be replaced is the last one and does not have remaining teeth beyond it. These bridges have poor prognosis in the long run.
The resin bonded fixed partial dentures are those that are bonded to adjacent teeth using acrylic resins. Unlike the conventional bridges these resin bonded ones need less reduction of the adjacent remaining teeth and are therefore more conservative.