In case of severe alveolar bony resorption in the edentulous mandible, implant placement posterior to the mental foramen is a problematic procedure. Inferior alveolar nerve transpositioning is often required for implant installation on premolar
and
molar area for the purpose of more functional prosthodontic rehabilitation. Installation of longer implant fixtures can be performed by this method avoiding the damage of inferior alveolar nerve.
We checked Orthopantomograph or MPR(multiplanar reformatted) CT in order to evaluate the anatomical relationship of residual ridge and inferior alveolar nerve accurately and experienced mild to moderate nerve damages on 11 sites, in 7 patients
who
were
received transpositioning of inferior alveolar nerve from 1992 to january, 1995, and had performed serial follow-up study about the recovery of neurosensory function periodically. We can extended the application of implant surgery and get several
results as follows about sensory nerve recovery.
1. In all of the cases, the decrease of sensory function were observed postoperatively.
2. Tinel's sign appeared in 8 cases at 1-2 months postoperatively and continued for 2-3 months and disappeared at 6 months postoperatively, and the type of sensory dysfunction was changed as anesthesia, dysesthesia, paresthesia in order and to
the
normal sensation in 63.6% at 1 year postoperatively.
3. The pain sensation in skin surface was recovered in 68.2% at 6 months, in 81.8% at 12 months postoperatively and the tactile sensation was recovered in 40.1% at 6 months in 77.3% at 12 months postoperatively.
4. Two-point discriminations were checked as normal range in 54.5% of the operation sites at 6 months, 81.8% at 12 months postoperatively, and the area of sensory dysfunction on skin surface diminished by degrees with time.
5. The nerve damage appeared in all the cases postoperatively and the sensory recovery times were different depend on to the amount of nerve damage during the operation. The degree of the recovery of sensory function increased with time, but the
permanent slight depression of sensory function remained in a few cases. Therefore patients should be informed enough about that preoperatively.
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