Prostho Plus by Piers Anthony

"Then you do not question League policy or practice?"
    That was better. "Of course not. I should hope the League has the best interests of the planet in mind."
    "Then you will retract your demand that all gold be removed from the teeth of our citizens?"
    That was the sticky point. "No."
    There was an angry flurry of sounds from the transcoder. Trach bowed his head, disappointed.
    "That is," Dillingham said carefully, "I will not make such a retraction without the full consent of the League." Trach's head popped up again hopefully, and the clamour faded. "Since it was my careless utterance that precipitated this crisis, I feel it is best to obtain competent advice before making any further statements on the matter."
    Another pause. "The advice—of the League?"
    "Nothing less will do."
    The background discontent metamorphosed into background approval. Trach nodded unobtrusively. Dillingham was off the hook for the moment—if he didn't blunder again.
    "A wise stipulation," the spokesman said. "What gave you the idea we might object?"
    And so to the critical point. "On my planet, the teeth are use principally for the mechanical reduction of the food, and only secondarily in connection with speech. Our teeth have no internal mechanisms—none, at least, of an electronic nature. Therefore our dentists think largely in terms of a single function: mastication. When I looked into this patient's mouth, that was what concerned me."
    "Astonishing," the spokesman agreed.
    "Then I discovered that you generate an electronic signal in your teeth, which is your means of communication. Because this is natural for you, and biological, you may not be aware of the precision required to modulate your signal so effectively, just as few human beings are aware of the sophistication of their own bodily adaptations. The fact is, the tiniest electro-magnetic interference in the immediate vicinity of your teeth can play havoc with your control, both broadcasting and receiving. The electrolytic action of the trace impurities in your gold alloy with the fluids of the mouth generates just enough current to tarnish the metal—and to distort the adjacent fields within the tooth. Thus the signal sent by a person with such a situation differs from that he intends. When this becomes severe enough to be noticeable, you have aphasia."
    He shook his head, glad they were listening (receiving) attentively. "Possibly the field generated by the normal teeth is enough to start the surface erosion. Because the interference is external to the tooth, you will find no internal malfunction, which I know can be baffling. At any rate, because of your particular mode of communication, you can't afford metallic fillings until much more is known about this effect. That is why I recommended the removal of all gold from the teeth. Since aphasia is hardly my field, I should not have spoken prematurely. You have helped me to understand that."
    "But it is in our field," the spokesman said somewhat condescendingly. "We are concerned with the complete function of the teeth, though it had not occurred to us that trace tarnish would—" He stopped, unwilling to admit ignorance.
    "We had a great many problems developing suitable metallic restoration on Earth," Dillingham said. "The work I inspected here was expert. I can appreciate your reluctance to—that is, I'm sure the expenditure of time—"
    "We do not place convenience ahead of the welfare of the patient," the spokesman said loftily.
    "Then of course there is the expense. Gold is a rare and costly substance, and the waste involved in removing—"
    "To hell with the expense!" the spokesman said. Dillingham glanced at his transcoder, startled. When had he programmed that vocabulary into it?
    "Now if you'd like me to retract—"
    Hubbub. Trach was maintaining a straight reptilian frown over a suppressed smile. The representatives of the dental league were suddenly aware that they had cut the ground out from under their own position.