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CONSIDERATIONS FOR THE ORTHODONTIC CORRECTION OF
- IMPACTED TEETH
CONSULTATION:
Remember that patients with impacted teeth often think that the erupted teeth look good and that they do not
need orthodontics. They might think that the tooth is just slow to come in. Consultations need to be thorough.
It is critical that the patient be fully informed about the consequences of treatment as well as non-treatment.
See standard informed consent language below for IMPACTED CUSPIDS and ANKYLOSED TEETH.
Both issues below may apply:
IMPACTED TEETH - Impacted teeth stay partially or completely under the gum due to lack of room to emerge or
for no apparent reason. Wisdom teeth are the most commonly impacted teeth and may need to be removed.
Other teeth if impacted, may need to be uncovered by an oral surgeon and have attachments glued or bonded
to them to assist the orthodontist in their movement. Occasionally the surgical process needs to be repeated.
Not all impacted teeth can be moved successfully, which may necessitate their extraction. Roots of adjacent
teeth may be affected.
ANKYLOSED TEETH – In some instances teeth will not move because they are directly attached to the bone
(ankylosed). An ankylosed tooth may need surgery to aid in its movement or it may need to be removed.
Diagnosis: (see samples A. and B. below)
Surrounding teeth
- The relationship and condition of the adjacent teeth is a factor in the attempt to bring in an impacted
tooth. - Commonly an impacted upper cuspid upper cuspid will cause a distal tipping of the lateral crown and a
increase in the facial “torque” of the lateral crown. That is caused by the cuspid crown pushing the lateral
root palatally and mesially. - Location. (See Sample C)
- Some locations have a poor prognosis and alternatives should be explored. Make sure the explanation
and choices are presented, accepted and signed by the parent/patient. - X-ray evaluation
- A NewTom 9000, obviously, would be the best x-ray evaluation, but is not always available, affordable, or
necessary for the patient. Never rely on just one view of the impacted tooth or teeth. (see samples A and
B) They are of the same tooth!! - Progress x-rays are critical to monitor adjacent teeth, bone condition and tooth movement.
- Visual and palpation.
- Look and feel the vestibule(s) and palate for indications of the location of the tooth.
Treatment planning:
Prognosis; Factors influencing the prognosis are:
1. Patients age
2. The potential pathway of movement
3. Cusp tip and root tip location
4. Ankylosis
Space:
Opening space prior to impacted tooth movement is usually advisable. Open coil springs are usually the
auxiliary of choice.
Extractions and sequencing
When bicuspids or other teeth are to be removed to make room for the impacted tooth, it would be a good idea
to validate the movement potential of the impaction prior to extracting other teeth.
Anchorage possibilities are :
1. Full size rectangular archwire
2. TPA (can use extension arm from TPA)
3. Bonded linguals in segments
4. Removable appliance (tissue borne)
Exposure:
1. Oral Surgeon
Experienced and capable of bonding and placing gold chain correctly.
Recommended to visit the oral surgeon to make sure his/her technique is good.
Packing the tissue open after removing the bone in the eruption pathway to an undercut area is helpful when
possible.
2. Periodontist
Tissue management is usually good.
When possible, avoid damaging the soft tissue in the area of the buccal cervix.
Attachments:
Bonding buttons or brackets to the impacted tooth. A gold chain is attached to the button or bracket
Occasionally a small hole through the impacted cusp tip can be used.
Archwires:
Archwires should be heavy enough not to reciprocate the movement of the impaction.
Auxiliaries and traction:
Lever arms from TPA or from the archwire mesial to molar tube. (see picture of lever arm sample E.)
Power thread, power chain, and tying to a compressed spring can be used
Overlay arches -- these are lighter arches tied over the body wire, that deflect toward and are tied to the
impacted tooth.
Mechanics- Type and Direction
The direction of movement is not always a straight line to the final position. Often the initial direction of an upper
cuspid needs to be distal (to clear the anterior roots) and occlusal (to accomplish visualization and allow
improve the bonded attachment with a bracket.
Rapid cuspid extrusion, if the tooth has a closed apex, increases the potential for pulpal necrosis.
Lever arms, power chain power thread (same material as power chain), overlay or piggyback mechanics are the
most common.
Do not use a light wire as anchorage. (See Sample D)
Traction can go from the button, through a circular loop in the rectangular wire or extension arm, then on back
to the molar for maximizing efficiency.
Final positioning
Remember the relapse potential of the tooth especially with incorrect root/crown torque. If there is not proper
buccal root torque in an upper cuspid that was moved from the palate, the crown will relapse into a crossbite.
Retention
Normal retention should be adequate.
Complications:
The tooth may not successfully move or stop moving during treatment. Sometimes luxation by the oral surgeon
may dislodge the tooth from small ankylosed points. If movement still fails, the tooth may need extracting.
Locations may be too difficult for surgery. If the tooth is too difficult or dangerous to remove and is out of the
way of adjacent teeth, it could be left alone but watched yearly with an X-Ray.
Use multiple x-rays to visualize the position of the tooth. The two x-rays below are of the same tooth.
Samples A. B.
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Use stabilizing upper archwire and preferably
traction only to an auxiliary arm from a TPA
Sample D
. (Warping of arch from poor anchorage)
Sample C. To be added
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Sample E.(lever arm can be used from triple tube or TPA to provide force and
directional control to an impacted tooth)
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- IMPACTED OR ECTOPIC LOWER SECOND MOLARS
| Use power thread or chain from button on the impacted tooth to the loop on the extension arm of the 6 to 6 |
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