A New Sliding Genioplasty “Stepped genioplasty” Technique in Order to Avoid Injuring Mental Nerve of Skeletal Class III.

In the Skeletal Class III, genioplasty is often performed in addition to sagittal splitting ramus osteotomy.

However, sliding genioplasty with much being applied to Caucasian mandibular retrusion is at increased risk of the injury of the mental nerve when we apply it to the Japanese that there is much that travel motion of the canalis mandibulae runs lower jaw inferior margin in premolar part neighborhood.

Therefore we evade nerve injury by sloping an osteotomy line of the Genioplasty.

We devised sliding genioplasty which evaded risk of the injury of the mental nerve by being able to hit a step in osteotomy line about a cuspid part in consideration of travel motion of the Japanese canalis mandibulae this time.

We report the brief description.

An operative method

We conduct the incision by the incision that linked the both cuspids moderately in the upper part of the gingivobuccal fold (Gullwing Incersion).

Then, we exfoliate mental region inferior margin for the incision advice, an empty hand to reach the periosteum while protecting mental nerve.

We push forward break away dorsad in buccal side of the submandibular marginal part and confirm position of the foramen mentale subsequently.

As for the setting of the osteotomy line, a seal does mid saggital plate, denture middline, the tooth axis of the each side cuspid becoming the baseline for a bone interview.

The osteotomy line takes its eyes off it in 3-4mm, the chin pore in the 4-5mm lower jaw inferior margin direction from cuspid root apex and sets it.

We measure position of the foramen mentale and travel motion position of the canalis mandibulae for an actual value from the lower jaw inferior margin using X-ray computed tomography pictorial image three-dimensionally and find margin of safety and perform it on this occasion.

The osteotomy can cut only hard tissue without we begin with the labial cortical bone, and injuring a soft tissue of the lingual part by using Cavitron ultrasonic surgical aspirator for hard tissues.

Also, surgery in the bright field is enabled without being disturbed for bleeding by a microbubbling effect of the Cavitron ultrasonic surgical aspirator.

After having performed an osteotomy, we move mental region bone chip in the appointed site and fix it.

The osteosynthesis uses an absorbent penetration screw, but is advantageous in that we can perform the penetration screw settlement of the step part relatively strongly.

The Genioplasty by the fundamental law could give good form without the step in the bone amputation stump of the submandibular marginal part postoperatively, and the Skeletal Class III which ran inferior margin neighborhood was able to infer travel motion of the canalis mandibulae with effective manner.