How Dental Bridges Work
Four Types of Dental Bridges
A dental bridge is a way to replace one or more missing teeth. Some people use the term bridge to describe a removable appliance that replaces missing teeth, but dentists do not. Dentists use the term bridge to describe something that attaches to the teeth with dental cement and is not removable. There are many different types of materials and designs for bridges, and in general, we can divide them into four different types.
Common Considerations of All Dental Bridges
In all types of dental bridges, the replacement tooth is called a “pontic”. The pontic provides chewing surface and connects to the underlying support via structures called retainers. (The retainers are different based on the various type of bridges.).
All bridges require the support of adjacent structures (the neighboring teeth in most cases), and the pontic does not penetrate the gum tissue or jawbone, but rather rests on top of them. All bridges also require special oral hygiene considerations as they have connections with the adjacent teeth, preventing normal flossing.
Because bridges use other structures for support (either a neighboring tooth or dental implant), the health of those neighboring structures is of utmost importance for long-term function. A problem on a supporting tooth or implant affects the entire bridge.
The chewing force that the pontic provides does add stress to the adjacent teeth as they absorb the additional force. This is why the size of the replaced tooth must be significantly smaller than the size of the retainer teeth.
We call the most common type of dental bridge simply a traditional bridge. A traditional bridge uses dental crowns to completely cover the exposed portion of neighboring teeth on both sides of the to-be-replaced tooth. The pontic connects to the retainer crowns so that the bridge forms one large unit. A bridge consists of the number of pontics plus the retainer crowns on both sides, so a traditional bridge replacing a single missing tooth is a three-unit bridge.
Traditional bridges should only replace one to two missing teeth. The strength and longevity of a traditional bridge comes from the root structure and periodontal (surrounding bone and gum) support of the retainer teeth. Dentists must choose retainer teeth with long roots and healthy bone and gum support to provide a bridge that will last for many years.
A cantilever bridge uses a retainer on only one side of the pontic. This means that the pontic has only a single connection to a retainer. In order to picture a cantilever bridge, imagine a diving board over a swimming pool. The farthest end of the diving board flexes when it bears weight.
The most common retainer for a cantilever bridge is a full dental crown. When choosing the retainer tooth, the patient and dentist should select the tooth with the strongest root and surrounding support structures. Typically, this will fall to the tooth behind the missing space.
This potential flexing is cause for concern with cantilever bridges. There are extremely limited cases in which a cantilever bridge can function well over a long period of time. More often, the flexing and torquing forces allowed by the design of cantilevers either dislodge the bridge or damages the underlying retainer tooth.
Cantilevers may work well as a replacement option for very small front teeth that provide little to no chewing force.
A Maryland bridge is a spin on the traditional bridge, using small wings as retainers instead of full dental crowns. The wings rest on the biting surface of adjacent teeth and attach via a bonded dental cement. Maryland bridges are wonderful options for replacing a single front tooth, and they are the most conservative dental bridge available. They require the smallest amount of removal of healthy tooth structure if any at all.
Maryland bridges are not great options for back teeth as they may be easily dislodged by heavy chewing forces. If they are used on back teeth, it is a temporary solution at best.
The disadvantage of a Maryland bridge is its risk for de-bonding and falling off. As these are typically used to replace front teeth, this can lead to an embarrassing dental emergency. It is important for recipients of Maryland bridges to understanding that once this type of bridge de-bonds, it is highly likely to do so again. The subsequent bonds are never as strong as the original one.
An implant-supported bridge follows the same form as a traditional bridge, using dental implant abutments instead of adjacent teeth as retainers. The bridge retainers over abutments also use a full dental crown form, with the abutments shaped similarly to a tooth prepared for a crown.
The advantage that an implant-supported bridge maintains over a traditional bridge is that dental implants and abutments cannot get cavities. This reduces their failure rate. Traditional bridges often fail due to new cavities that develop on one or both of the retainer teeth. However, both traditional bridges and implant-supported bridges can fail due to periodontal disease, which destroys the surrounding bone and gums of both teeth and implants.
There are a few disadvantages of implant-supported bridges. They do require a surgical phase in which the implants are placed into the jawbone. They are also more expensive than a traditional bridge because of the added expense of the implant surgery. The time required for implant integration into the bone makes this the bridge option that takes the longest.
The support of the dental implants and the impossibility of cavities makes this the bridge option that has the highest long-term success rate.
More Questions about Replacing Missing Teeth with Dental Bridges?
Call your nearest Premier Dental of Ohio location today to schedule a consultation with one of our skilled Premier Dental dentists. We will assess your current needs and discuss every tooth replacement option available to you.