With Asian lower jawbone reduction surgery, also known as jaw shaving or mandibular angleplasty, the enlarged outer portion of the mandible is cut off or filed down using a rotating metal burr introduced through either a skin incision or a hidden incision inside of the mouth.

The inner portion of the masseter muscle may also be removed without reducing function in patients with muscle overdevelopment (hypertrophy).

The goal is to create a more oval jaw line with a less flattened angle. Botox may be injected in the months before surgery to thin an overly-thickened masseter muscle and make the surgery easier.

The mandible bone may be surgically reduced by employing several methods:

With "mandible angle resection," the triangular end of the bone closest the ear is completely removed (red dots). This is particularly helpful in those patients where the jaw seems too square when viewed from the side.

When the jaw appears too square from the front, a procedure known as "sagittal splitting osteotomy" allows the the outermost portion of bone to be split away and removed from the rest of the mandible, thus thinning the bone and reducing its outward flare (yellow area).

The main risks are injury to the nerve that supplies sensation to the lower lips and teeth and over-resection that excessively narrow the jaw angle. Inappropriate surgical bone resection can leave a previously well-proportioned face looking oddly "alien."

In some patients, bone surgery may be followed by periodic Botox injections to shrink overlying muscular tissue and increase the slimming effect.

Most jawbone surgery is performed in the Orient where the procedures are in higher demand and sometimes offered for less obvious indications.