Prostho Plus (2 page)

How was he to define the problem? He saw no evidence of decay or abrasion. Every surface gleamed cleanly white. While he was hardly in a position to make an accurate diagnosis, all the evidence suggested health.

He tapped an incisor experimentally. It was solid. All the teeth were firm and without blemish. Why, then, had this patient come?

Dillingham set down his instruments and stood back. "I can't help you," he said, trying to ignore the pointing prism and hoping his tone would put the message across.

The crewman closed his mouth, stood up, and went to the door. The captain handed over the prism and approached. Dillingham waited, uncertainly.

The captain took the chair and opened his mouth. Had they gone to all this trouble for a routine checkup?

Dillingham shrugged, washed his hands again, and brought out a sterile set of instruments. There didn't seem to be much he could do except oblige their whim. They were aliens, and it could be dangerous to cross them. He looked into the captain's mouth.

Suddenly it all came clear.

The crewman's mouth had been a healthy one. This mouth was not. The same peculiar pairings were present, the same oddly-angled occlusals—but several of the back teeth on the left side had badly ravaged lingual surfaces.

The visitors had anticipated one of his difficulties, so had shown him the healthy set first, as a model. Now he did have some idea what was wrong,

"Dr. Dillingham!"

The crewman whirled to aim the prism at Miss Galland's voice. Had half an hour passed so rapidly? "Emergency!" Dillingham called to her. "I'll be tied up all afternoon. Handle it as well as you can."

"Yes, Doctor," she replied with only the slightest hint of disapproval. His present procedure was at best highly irregular; with a real emergency, he should have brought her into the operatory to help. Miss Galland was a highly competent dental assistant, but he tended to use her more and more as a receptionist because she made a much better impression on recalcitrant patients than he did. She really deserved to see this astonishing set of teeth—but he still did not dare expose her to the mercies of such questionable aliens.

Meanwhile, he knew that the problems entailed by his unexplained cancellations would be tactfully handled.

He probed the first of the damaged teeth: the second bicuspid, for want of anything resembling a properly descriptive term. The captain jumped; no doubt about its sensitivity. It looked as though some potent acid had eaten into the surfaces and stripped away the enamel and much of the softer dentin beneath (again applying human terms to the un-human). It had been a recent accident; there was no sign of subsidiary decay. But the present condition was obviously uncomfortable and probably quite painful, and certainly constituted a hazard to health.

Dillingham observed that the buccal surfaces had also been etched. Only an X-ray, that he could not risk on the alien flesh, could establish possible penetration of the pulp. This was a rough case.

It might be possible for him to repair the damage, or at least cover it with a protective cast—but only if he could anaesthetize the jaw. Novocain was out of the question; any drug might be fatal.

The whole thing was ridiculous. "This is as far as I go," Dillingham said firmly. "I hate to leave you in pain, but my ignorance could kill you. I'm sorry." He crossed his arms and stood back.

When they saw that he was not going to proceed, the crewman levelled the prism at him again. The Captain stopped that with a gesture. He stood up and recovered the instrument. He made sure he had Dillingham's attention, then aimed it at the wall and flicked a finger.

A spot appeared on the wall. Smoke curled up.

The captain made an adjustment and aimed again. This time a portion of the wall exploded, leaving a charred hole.

He returned it to the first setting and pointed it at Dillingham. The message was clear enough.

But what would be their reaction if he botched it? Should he violate his professional ethics under duress? Dillingham shook his head, sweating. Perhaps they were bluffing.—

"Dr. Dillingham!"

Oh, no! Miss Galland had come back.

The captain nodded to the crewman, who whirled to unlock the door.

"Judy! Get away!"

"Doctor! What are you—"

Then the door was open and the crewman charged out. Judy Galland screamed.

Dillingham lunged at the captain, but the officer was ready. The beam from the prism stabbed savagely into his leg. Dillingham fell, clutching at the wound.

When the pain abated, he found Miss Galland standing beside him, her dark hair disarranged. The crewman had the prism again, and was covering them both.

"Doctor! Are you hurt?"

It was just like her to overlook the incredible in favour of the commonplace. She was not the fainting type, fortunately. He inspected his leg.

"Just a burn. It was set on low." He stood up.

The captain resumed his seat. The crewman aimed the prism at the girl.

So much for resistance. The show would go on.

"I don't think they mean any harm, Doctor," Miss Galland said. "They must be desperate." No hysterics from her; she had adapted to the situation far more readily than he.

Dillingham approached the patient. He had to quiet the shivering of his hand as he held a probe. Aliens, heat-beams—this was hardly the ordinary fare of a dentist.

But the problem of anaesthesia remained. Massive excavation would be required, and no patient could sit still for that without a deadened jaw. He studied the situation, perplexed, noting that the crewman had put away the prism.

The captain produced a small jar of greenish ointment. It seemed that this contingency had been anticipated. These creatures were not stupid.

Dillingham touched his finger to the substance. There was a slight prickly sensation, but nothing else. The captain gestured to his mouth.

Dillingham scooped out a fingerful and smeared it carefully along the gingival surfaces surrounding the affected teeth. The colour darkened.

The captain closed his mouth. "How do they
chew
?" Miss Galland inquired, as though this were a routine operation. She had assumed her role of assistant naturally.

He shrugged. "The moment they take their eyes off you, slip away. We can't be sure of their motives."

She nodded as the captain reopened his mouth. "I think they're doing just what
we
would do, if we had trouble on some other world."

Dillingham refrained from inquiring just what type of literature she read during her off hours. He probed the raw surface that had been so sensitive before. No reaction.

So far, so good. He felt professional envy for the simplicity of the alien anaesthetic. Now that he was committed to the job, he would complete it as competently as he could. His ethical code had been bent by the aliens but not broken.

It was a full-scale challenge. He would have to replace the missing and damaged portions of the teeth with onlays, duplicating in gold as precisely as he could the planes and angles witnessed in the healthy set. While it would have helped immensely to know the rationale of this strange jaw, it was not essential. How many centuries had dentists operated by hit or miss, replacing losses with wooden teeth and faithfully duplicating malocclusals and irregularities? The best he could hope for would be fifty per cent efficiency—in whatever context it applied—yet if this stood up until the patient returned to his own world, it sufficed. There was no perfection.

Would a gold alloy react unfavourably with the alien system? He had to chance it. Gold was the best medium he had to work with, and another metal would be less effective and more risky. A good cobalt chromium alloy would be cheaper, but for really delicate work there was no substitute for gold.

He drilled and polished, adjusting to the old internal convolutions, while Miss Galland kept the water spray and vacuum in play. He shaped the healthy base of each tooth into a curve that offered the best foundation. He bored a deep hole into each for insertion of the stabilizing platinum-iridium pins. He made a hydrocolloid impression of the entire lower jaw, since the better part of the reconstruction would have to take place in the laboratory.

Both aliens started when he used the hydrocolloid, then relaxed uneasily. Evidently his prosthodontic technique differed from that of their own world.

"Sorry," he said, as much to himself as to them. "Since I am not familiar with your methods, I am constrained to rely upon my own. I can't rebuild a tooth by guesswork."

"That's telling them," Miss Galland agreed.

He needed a model of both sides of the jaw because it was bilaterally symmetrical. A mirror-image reproduction of the right side might reasonably do for the left. He ignored the upper jaw. He knew nothing of the proper interaction of these surfaces, so the opposing pattern could only confuse him. He didn't want human preconceptions to distort the alien pattern.

But his curiosity about the way those incredible teeth functioned was hard to suppress.

He worked loose the hardened cast. He applied a temporary layer of amalgam, so that the jaw would not be sensitive when the anaesthetic wore off. Then he had to explain to the aliens by means of pantomime that this was not the end product of his endeavours.

Miss Galland brought a plaster model of human dentures, and he pointed to the cut-away teeth and lifted out the mock reconstructions, then gestured towards the laboratory. After several repetitions the captain seemed to get the idea. Dillingham led the way, with captain, Miss Galland and crewman following in that order. The major portion of the job was coming up.

Patients seldom saw the lab. Few of them were aware of the enormous and precise labours that went into the simplest inlay, onlay or crown. This time, at least, he would have an attentive audience for his prosthodontic art.

Dillingham rinsed the impression immediately and immersed it in a two per cent solution of potassium sulphate while Miss Galland set up the equipment. There wasn't much else she could do, because special skill was required for the early stages.

The captain watched the routine with what Dillingham was sure was amazement. The aliens knew no more about the realities of dentistry than local people did! But what had they expected? Surely the techniques of North Nebula—to invent a home for the visitors—had points of similarity. Physical laws applied rigorously, whatever the language or culture.

He filled the impression with a commercial stone preparation, vibrated out the bubbles, and inserted the dowels and loops for individual handling of the teeth. While the die set, he simulated the remaining steps for the captain: the intricate wax mock-up of the onlay pattern for each tooth; the attachment of the sprue, so that the pattern and subsequent cast could be handled effectively; the investment, or formation of a durable impression around the wax pattern; burnout, to free the investment of wax and leave a clear mould for the liquid metal; casting (he didn't even try to explain about the problems of expansion and contraction of gold and cast): and finally the pickling, finishing and polishing of each unit.

The captain's eyes seemed glazed, though the procedures were elementary. Here in the lab Dillingham was master, whatever the larger situation.

At last he manipulated the hands of the wall clock to show how many hours would be required for all this. He assumed that if the Nebulites knew enough about Earth to locate a specialist when they needed one, they should have mastered local timekeeping conventions.

The captain was not happy. Had he thought that an onlay was the work of a few minutes? Probably, like most patients, he hadn't thought about it at all. Everybody knew dentists spaced out the time between appointments merely to boost their exorbitant prices! Ha (brother!) ha!

The captain produced what appeared to be a hard plastic rod and chewed it meditatively on his good side. Dillingham was afraid at first that it was another weapon, but saw that it was not. Well, every species doubtless had its vices and mannerisms, and this was certainly better than chewing tobacco or gobbling candy.

The patient passed the rod to the crewman, who glanced at it with interest but did not choose to add any toothmarks of his own. No conversation passed between them, but abruptly the captain left. The crewman took a seat and kept the prism ready.

Evidently they did not intend to leave the captives to their own devices while the onlay was in preparation.

"They don't miss any bets," Miss Galland said ruefully.

Dillingham shrugged and bent to his work. It seemed that the surest way to get rid of the visitors was to complete the operation. He sawed his die into four separate segments, one for each damaged tooth, and plunged into the complex portion of the job. The wax he applied had to be shaped into the exact pattern of the desired cast. This, not the original tooth, was the actual model. The die determined the juncture with the living tooth, but the artistry lay in sculpting the upper surface of the wax into a serviceable and aesthetic duplicate of the healthy original.

He set the cruder plaster cast of the captain's jaw before him and began the most difficult construction of his career. It was not an image he had to make, but a
mirror image,
and his reflexes were hardly geared to it. Each of the four patterns would take several hours.

Night fell as he completed the second pattern. A new alien came to replace the crewman, but there was no chance to escape. They chewed sociably on rods, exchanged them, and parted.

"Dr. Dillingham!" Miss Galland exclaimed. "That's how they talk! They make marks like that old-wedge-writing."

It made sense. "Cuneiform," he agreed. That explained what the teeth were for! But the revelation, while satisfying intellectually, didn't help them to escape. The new guard was as vigilant as the first.

Night passed. Miss Galland slept on the emergency cot while Dillingham kept working. They both knew that help was unlikely to come, because the aliens had shown up on Friday and there would be no appointments for the weekend. Dillingham lived alone, and Miss Galland's room-mate happened to be on vacation. The captain had been quite lucky.