The Significance of Teeth in Pollution Detection

THE SIGNIFICANCE OF TEETH IN POLLUTION DETECTION IRVING M. SHARON* Introduction Teeth are storehouses of invaluable information for biological, physical , and medical sciences. Human and animal teeth afford accurate monitoring with collection techniques that are benign, ethical, noninvasive, and painless. Teeth can provide keys to provenance, development, birth defects, and disease impairment. Routinely analyzed and monitored, teeth can indicate exposure to pollutants and provide a permanent, cumulative, qualitative, and quantitative record of insults. A tooth bank can provide an alternative to the current, limited methods for identifying harmful substances before they affect our health and that of our progeny [I]. Biomonitoring.—To effectively monitor the air, water, soil, and food that affect our health, new techniques are required. Teeth offer unique advantages for both concurrent and retrospective pollutant monitoring. A majority of the public, many biologists, physicians, and dentists are unaware of the considerable dental literature pertaining to pollution. Biobanking.—Specimen banking is the collection and storage ofbiological samples whose chemical integrity is assured [2]. Specimens in current pilot banks provide for limited studies as many body tissues, fluids, and organs reflect only transitory contamination and are not readily stored. Because of these limitations, it is common to extrapolate human response from animal studies. Establishment of a tooth bank offers a unique and practical complement to current specimen banks. Teeth become comprehensive, permanent records ofa specific and unique exposure history. In addition, both human and animal teeth are readily accessible and easily stored. ?School of Dentistry, University of the Pacific, 2155 Webster Street, San Francisco, California 94115-2399.© 1988 by The University of Chicago. AU rights reserved. 0031-5982/89/3201-0615$01.00 124 I Irving M. Sharon ¦ Teeth in Pollution Detection At present, the physiological effects of pollutants are measured by overt symptoms and signs. Subtle alterations in teeth can provide a premonitory warning system for preventive action. Deciduous teeth are ideal for a retrospective study since enzymes are influenced by species, strain, sex, and age [3]. Teeth as an ideal bank deposit.—An organism's metabolic process is mirrored in the developing oral tissues [4]. Enamel defects are specific, chronological markers of insults to an infant or fetus. Each tooth has its own timetable of development, and the time span for tooth formation is longer than that of any other organ system [5]. Human teeth start developing during the sixth week in utero. Ten buds in each jaw become the deciduous or temporary teeth, later replaced by permanent teeth [6]. The inorganic portion of teeth and bone is hydroxyapatite, with physical properties similar to mineral apatite [7]. Enamel and dentin respond with clocklike accuracy to metabolic alterations . Human deciduous teeth reflect insults that occur from 4 months, in utero, when calcification begins, until completion of 10 months [8]. Human permanent teeth reflect exposure from shortly before birth through 18-25 years for third molars (wisdom teeth) [9]. Unlike bone, teeth are resistant to chelation, do not resorb or remodel during calcium withdrawal, and are ideal retrospective models [10]. Heavy metals in permanent teeth have been determined in situ from enamel biopsy samples [H]. The chemical composition of tooth minerals reflects the composition of serum and calcifying fluids at the time of calcification [12]. Tooth rings, similar to tree rings, act as a kymograph to permanently record physiological events or insults [13]. Rodent and other animal teeth also permanently record biological events that take place during growth and development. Rat incisors erupt continuously and renew themselves approximately every 40-50 days, while the static molars reflect past exposure [14]. Frogs [15] and fishes [16] provide a continuous supply of erupting and shedding teeth. The teeth on the tongue and roof of the mouth and in the jaws of bony fish are systematically replaced by successional teeth [17]. Lemon shark teeth are replaced every 9 days and sometimes function for only 2 days [18]. Some insecticides bioconcentrate in several fish species [19] so that a system for ongoing monitoring is a practical alternative to other types of ambient water chemical testing [20]. Founding the tooth bank.—It is possible to develop an accurate, costeffective , and timely system to monitor today's growing human health hazards. Dental investigators can team...