Dorothy M. is understandably nervous as she waits in the doctor's inner office. She absently drums her fingers on the smooth table top, examines her nails, then glances around the room. She notices a keyboard and the blank screens of a TV and computer monitor built into the wall. She has come to the Maxillofacial Surgery Center in Fairfax because her family dentist recommended a consulation with an oral surgeon specializing in orthognathics.

Dorothy still isn't exactly sure what orthognathics can do for her, nor is she thrilled with the prospect of having surgery. But neither has she ever been pleased with being -- as she once heard herself cruelly described -- a "chinless wonder." As she waits, she wonders what a computer might have to do with all this. Dorothy is about to be surprised.

Jaw deformities aren't unusual in this country. The most recent public health census estimated that 11 1/2 million Americans -- about one in every 20 -- have mild to extreme abnormalities in the development of the upper and lower jaw. Called "dentofacial deformities," they not only affect one's appearance but may also cause jaw, facial and neck pain or contribute to arthritis, headaches and early loss of teeth.

For those jaw problems that can't be treated effectively by orthodontics alone, orthognathics -- a relatively new dental speciality -- may offer the only answer. Orthognathic (meaning "straight jaw") surgery uses a combination of orthodontia, microsurgery and now computers and video graphics to literally reshape and realign the jaw to improve both function and appearance.

Dr. Stuart Graves enters the office, greets Dorothy and sits at the keyboard. He and his partners (Drs. Henry Zussman, Peter Smith and Patrick Dolan) have the only oral surgery office in the Washington area (there are fewer than 20 in the United States) that combines advanced surgical techniques with a remarkable computer-video system called the Orthognathic Treatment Planner. Graves taps a few keys, and Dorothy is startled to see her face appear on the TV screen. Graves explains that the color photo taken of Dorothy in an earlier session has been fed into the computer and digitized. Now, explains Graves, he's going to show Dorothy what she might look like after surgery.

This isn't cosmetic surgery, though it can dramatically alter a person's appearance. Orthognathics is more concerned with the proper functioning of the jaw than with esthetics alone. A person with Dorothy's problem, microgenia (a weak or missing chin), could simply have a plastic surgeon create a chin using silicone implants. But the orthognathic surgeon sees the absent chin as a health problem. Dentofacial deformities -- a poorly developed jaw (retrognathism), gummy smile (maxillary hyperplasia) or a jutting lantern jaw (prognathism) or an absent chin -- may hide medical problems including difficulties in chewing and speaking, gum disease and misalignment of the teeth.

Graves places his hand on a mouse -- a playing-card-size device that lets him operate the computer without using the keyboard -- and slides it across what looks like a small light table. He explains to Dorothy that he's going to alter the photo of her face, adding and subtracting from the picture as he might sketch a drawing. Dorothy watches as Graves moves a cursor with the mouse, clicking its buttons as he magically transforms the photo, extending her jaw line and reshaping her missing chin. None of this would have been possible a few years ago. Dorothy would have been shown not a photograph but a hand-drawn profile, an example of the proposed changes to her jaw and face. Looking at those stark outlines of curves and angles, she would have had to visualize a face that existed only in her imagination.

Orthognathic surgery has changed rapidly in the last decade. In 1978, patients like Dorothy faced 11 hours of surgery, a week in the hospital (including a stay in intensive care) and the unpleasantness of having their jaws wired shut during recovery. With today's revolutionary microsurgical techniques, similar procedures take two to five hours, and wired jaws are not necessary. Patients are usually discharged the next day without facial scars.

Computers don't do the surgery, of course, nor can the software of the Orthognathic Treatment Planner magically diagnose a patient's problem. The developers of the $20,000 system -- California oral surgeons Melvyn Wishan and Mark Conover -- emphasize that their creation isn't a silicon oracle but another tool in the physician's black bag, one meant to enhance, not replace, clinical experience and skill. Yet what orthognathic surgeons are doing with this integrated hardware-software system, available only since January 1986, is startlingly new.

After X-rays of Dorothy's head and jaw were fed into the computer, the information was used to make a line tracing of the bony structures of her jaw. The tracing, created by measuring and marking certain angles and distances on the X-ray (known as cephalometric reference points), can be used as a kind of surgical blueprint, showing where cuts and splices in the bone might be made. Oral surgeons normally make these tracings by hand, laying transparent paper over an X-ray picture, then marking and joining the points. Numerous tracings are made until the physician creates a sketch he thinks will lead to the best results.

The computer shortens this process from hours to minutes by calculating the cephalometrics and displaying a tracing on the monitor. Then, by having the computer simulate various jaw movements, the surgeon sees how restructuring may change facial balance and bite. The final tracing can be superimposed on the patient's X-ray, printed and stored in a data base.

The picture of Dorothy's new face is almost finished. Graves moves the mouse over the digitizing tablet, sliding about bits of Dorothy's jaw and face. Satisfied with the result, he taps a key and the computer prints the altered photo. Moments later, Dorothy holds the color picture in her hand and smiles at her new face.

The Orthognathic Treatment Planner is the first system to combine video imaging with cephalometric analysis. It is also a harbinger of more wonders to come as computers and video are applied to medical science. Complain if you like about technology dehumanizing society, but here at least is a computer with a human face. ::