Patients with a cleft lip and/or palate are often born with a missing tooth -- most often the lateral incisor (immediately next to the front central incisor). This may occur unilaterally or bilaterally, but special planning is needed to solve the functional and cosmetic problems the absence creates.
Who will be involved in dealing with the missing tooth?
Several dental specialists will be most important in planning treatment. Orthodontists align improperly placed teeth, while prosthodontists can replace missing teeth in a variety of ways. Oral surgeons perform surgery to the teeth, mouth, and surrounding areas of the head and face. Coordinated planning by all specialists involved is necessary for the best result.
What role does the orthodontist play in replacing a missing tooth?
The large majority of patients with clefts will require full orthodontic treatment, especially if the cleft has passed through the tooth-bearing ridge. Goals of treatment will be to line up the teeth in the upper arch, create an arch form that is harmonious with the lower dental arch, and line up the midline of the upper arch with that of the lower arch.
When a tooth is missing, the upper midline is usually shifted, so this must be corrected. A space is often opened up and maintained for later replacement of the missing lateral incisor.
During orthodontic treatment, an artificial tooth may be attached to the orthodontic wire as a temporary replacement for the lateral incisor. When the dental braces are removed, a removable retainer with an artificial tooth serves to maintain the space, and improve speech and appearance until a definitive restoration is made.
Is the missing tooth always replaced?
In many instances, the space for the lateral incisor will be orthodontically or surgically closed by moving the canine forward into the space normally occupied by the lateral incisor. This will then require modification of the canine to make it appear as a lateral incisor. This may be accomplished by adding plastic or porcelain dental filling material or a porcelain tooth crown to reshape its appearance.
What options are available for permanent replacement of the lateral incisor? Treatment options for the permanent replacement of the lateral incisor depend upon whether or not the cleft has been repaired with a bone graft. In a non-grafted dental arch, there are two options for replacement:
First, a removable partial denture may be used to replace the missing tooth. While this option may be made to look acceptable, it has several disadvantages. The removable prosthesis must cover most of the palate for support. This may cause irritation on the roof of the mouth or at the gumline where it rests. Many patients also object to the extra bulk and removable nature of the partial denture and report that it feels unnatural. This type of prosthesis is best as a temporary replacement as described above.
The second option in a patient without a bone graft is a fixed dental bridge. The missing tooth is restored with an artificial one connected to crowns (caps) on teeth on each side of the left. Because there is loss of supporting bone at each tooth on either side of the cleft, two teeth on each side must usually be crowned to give adequate support to the bridge. This type of prosthesis is not removable. Its contours and appearance look and feel more natural than a removable partial denture. However, it does require grinding down the support teeth in order to crown them and connect them to the artificial tooth. Cleaning between the crowned teeth also becomes more difficult since they are connected.
Can a fixed bridge be made immediately after braces?
In a teenager or young adult, the nerves and blood vessels in the tooth pulps are rather large. Drilling down these teeth for crowns may expose the pulps and require root canal therapy. Therefore, this type of treatment must usually wait until adulthood when the pulps are smaller.
What options are available for a patient who has had a bone graft?
Bone grafting the cleft site in the upper jaw creates a more normal arch and eliminates special restorative considerations relative to the cleft. A conventional fixed bridge as described above may be used. In many cases, only one tooth on either side of the cleft needs to be crowned, since the graft has stabilized the arch and added bone. If the teeth that hold the bridge are not otherwise in need of restoration, a resin-bonded fixed bridge may be chosen. This type of bridge requires much less tooth reduction of adjacent teeth, and there is no danger of nerve involvement. A porcelain replacement tooth is held in place by metal extensions cemented to the backs of the adjacent teeth. This is a more conservative restoration with regards to tooth preparation but still requires connecting teeth together.
The most natural, lifelike dental restoration for a patient with a bone graft is a single porcelain crown attached to an osseointegrated dental implant. This involves a surgical procedure where a titanium screw the size and shape of a tooth's root is inserted into the bone at the site of the missing tooth. It is covered by the gum for six months while the bone bonds to the dental implant surface. Then the implant is uncovered and an artificial tooth (crown) is attached. While this procedure does require minor surgery, it does not require cutting down or crowning any other teeth. Cleaning is also easier because the replacement tooth is not connected to any other teeth. This restoration does give the most natural result but does require that sufficient bone is present in order to hold the screw.
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