Treatment Alternatives for a Single Missing Front Tooth

By Brian J. Gray, DDS, MAGD, FICOI

There are many options available today that dentists can use to replace missing teeth. The decision to use one instead of another depends on many factors. The best treatment option can be different from person to person or from one area to another in the same mouth. The purpose of this article is to list the major treatment choices and some of the key factors involved in the treatment decision.

There are four major categories of restorations available for single tooth replacement:

• Bonded (Maryland) bridges
• Cantilevered bridges
• Conventional bridges
• Implants

All of the above-mentioned restorations cannot be taken in and out once they are placed. One of the main factors that will be addressed in choosing the type of restoration is tooth conservation. This relates to how much tooth structure has to be removed or altered on your teeth to be able to place the restoration. The goal in restoring a missing tooth is choosing the most conservative treatment that will provide you with a restoration that not only looks good but is functional and has long-term stability.

Bonded (Maryland) Bridges

Bonded bridges use the teeth adjacent to the empty space to help support the missing tooth. To do this, a very thin piece of metal or tooth-colored material is overlaid and bonded onto the back of the adjacent teeth. Running between these two bonded pieces is a tooth that fills in the empty space. The main advantage of a bonded bridge is that it is the most conservative type of restoration that uses the adjacent teeth for support. So, if the teeth next to the empty space look good and are not in need of any other type of restorations (fillings), a bonded bridge may be an option. However, because this restoration mainly gets its strength from bonding only, the long-term success depends highly on how your teeth fit together, how hard your teeth come together (grinding), and if your teeth are loose or not. So, how long can this type of bridge be expected to last? Looking at long-term research studies, the failure rate is about 25% at five years. This means that one out of every four bridges will come off within five years. Generally, they can be re-bonded when they come off, but once it is re-bonded, the chance of it coming off again increases.

Cantilevered Bridges

A cantilevered type of restoration only uses one tooth next to the empty space to support the missing tooth. Designs for this type of bridge can range from only using the back of the tooth (more conservative) to using a full crown to help support the missing tooth (less conservative). The choice of which is done again involves the amount of force (grinding) that is placed on the teeth and whether the tooth is in need of a full crown for any other reason. If used in the correct situation, with no history of grinding, this type of bridge has a higher success rate than a bonded bridge. This type of design is particularly useful for replacing missing lateral incisors.

Conventional Bridges

A conventional bridge is generally what people think of when they hear the word "bridge." This type of restoration uses full crowns on the teeth next to the empty space that are hooked together to help support the missing tooth. This type of bridge is the least conservative to the adjacent teeth because the most tooth structure has to be removed. Due to the increased strength of this type of bridge as compared to the others, it can be used in a wider variety of situations. How the teeth fit together and the amount of force (grinding) that is placed on the teeth, while still important to take into consideration, can be more predictably dealt with. This type of bridge is also the treatment of choice if the two adjacent teeth need to have crowns for other reasons. A conventional bridge also is one of the most predictable of all the options for replacing missing teeth. The failure rate of conventional bridges in the dental literature has a wide range of variation, ranging from 20% over 3 years to 3% over 23 years.

Implants

An implant is a titanium metal "screw" that is placed directly into the bone in the area of the missing tooth. Once the implant is integrated into the bone, it will act as the root of the missing tooth. A crown can then be made to fit onto the implant.

By far, implants are considered the most conservative of all the aforementioned procedures regarding the adjacent teeth. On the other hand, it may not seem conservative due to the surgical implant placement. To be able to place an implant in the correct position, two main things need to be addressed. The first is whether there is enough bone to hold the implant and the second is whether the roots of the adjacent teeth are tilted and in the way of where the implant needs to go. To overcome these concerns, you may require either bone grafting to increase the amount of bone or orthodontics (braces) to help move the roots of the adjacent teeth out of the way. Although this seems like a lot of work to do in order to place an implant, if the teeth next to the empty space look good and are healthy, an implant is the only way to replace the missing tooth predictably without altering your own teeth. As with the other treatment options, the amount of force placed on your teeth (grinding) can have an effect on the long-term predictability of implants and should be evaluated. The failure rate of implants in the front part of the mouth is currently around 5% at ten years.

There are many different factors to take into consideration when replacing a missing tooth. The above mentions some of the most important factors and should be used as a guideline. Since every situation is different, the final decision should be based on the specific criteria that are associated with that situation.