Teeth INDEX

Fig. 16.4 Index of fluorosis. Figure depicts moderate to severe fluorosis of the lateral incisor, canine, and second molar teeth index values of 4 and 5 (Copied from the University of Oklahoma Library Collection circa 1990, Source unknown)...

R = ratio (number teeth in gear divided by number teeth in pinion) The allowable K faetor is given by Allowable K = Material index number/Serviee faetor... 

Figure 1.1. Outline index map of the Japanese subduction zones. Thick lines with teeth are converging plate boundaries. Arrows indicate relative plate motions. Abbreviations su, Suruga trough sa, Sagami trough sf, South Fossa Magna triple junction och, Off Central Honshu triple junction ISTL, Itolgawa-Shizuoka Tectonic Line KSM, Kashima VLBl station (Uyeda, 1991).

Several methods have been developed for quantifying dental fluorosis. The most commonly used method is Dean s index [49], which classifies fluorosis on a scale of 0 to 4 as follows class 0, no fluorosis class 1, very mild fluorosis (opaque white areas irregularly covering <25% of the tooth surface) class 2, mild fluorosis (white areas covering 25-50% of the tooth surface) class 3, moderate fluorosis (all surfaces affected, with some brown spots and marked wear on surfaces subject to attrition) and class 4, severe fluorosis (widespread brown stains and pitting). The average score of the two most severely affected teeth is used to derive the classification. Other commonly used methods to rate dental fluorosis include the Thylstrup-Fejerskov Index (TFI) [50] and the tooth surface... 

Toothbrush (Fig. 5) is commonly used for teeth brushing. According to the 2003 Lemelson-Massachusetts Institute of Technology (MIT) Invention Index, the toothbrush was selected as the number one invention Americans could not live without [142]. 

On questioning the patient, you discover that he suffers from the more common type of lung cancer and is undergoing irradiation treatment currently. At this point you also notice that his right index and middle fingers as well as his teeth are stained yellow. 

Dr. H. Trendley Dean, US PHS Reported on his on observation of thousands of children in community with varying fluoride levels. His research established mottled enamel index, which measured the severity of the discoloring of the teeth enamel from fluoride. 

Smith BGN, Knight JK An index for measuring the wear of teeth. Brit Dent J 1984 156 435-438. Azzopardi A, Bartlett DW, Watson TF, Smith BGN A literature review of the techniques to measure tooth wear and erosion. Eur J Prosthodont Rest Dent 2000 8 93-97. 

The teeth and their environment / volume editor, Ralph M. Duckworth, p. cm. - (Monographs in oral science, ISSN 0079-6492 v. 19) Includes bibliographical references and index. 

Fluoride is both incorporated into enamel crystals and also affects the enzymes involved in enamel formation (Sect. 16.2.2), causing mottled enamel, a severe example of enamel fluorosis. Enamel fluorosis is evident as specks or white flecks on the enamel surface (Fig. 16.2b). In 1941, the public water supply of Aurora (IL) contained 1.2 ppm of fluoride (F), but only 5% of teeth exhibited fluorosis, mostly premolars and second molars. A sensitive index of... 

Fig. 16.5 Relationship of DMFT and index of fluorosis to water fluoride content. The left y-axis indicates the number of decayed missing and filled teeth from caries (DMFT) and the right y-axis indicates the index of fluorosis, a measure of the deleterious effect of fluoride on the enamel surface (see text). The x-axis indicates the ppm fluoride found naturally in the drinking water supply. Triangles indicate DMFT and circles indicate the fluorosis index in the same populations. The curves showing the decrease in caries and decrease in fluorosis intersect at 1 ppm fluoride in the water supply on the x-axis (Copy of Fig. 3 from Hodge HC, Smith FA. (1954). Some public health aspects of water fluoridation. American Association of the Advancement of Science Publication No 19 Washington DC 1954 AAAS 1954, pp. 79-109)...

The fluoride ion can replace the hydroxide ion in a crystal without significantly altering its structure, an isomorphous ion replacement. Fluoride also affects the enzymes involved in enamel formation, causing mottled enamel, a severe example of enamel fluorosis. White opaque patches on the normally translucent enamel indicate mild fluorosis. Fluorosis is measured on a grade of 0-5 where 1 through 3 indicate an increased cover of opaque white patches on the tooth surface, and 4 and 5 indicate an increased mottling. The two worst affected teeth make up an individual s score. The community s index of fluoridation is the mean score for all individuals. As the natural or artificial fluoride concentration of the water supply increases to 1 ppm, the mean number of cavities in 10-12 year-old children decreases from 7 to 3. Above 1 ppm fluoride, caries does not decrease much more, but the index of fluorosis increases markedly. This is the reason why public water supplies are fluoridated to only 1 ppm and not more or less. 

Body mass index (weight in kg divided by the height squared in metres) is a reasonable indicator of nutritional state, except when the patient is oedematous. Arm circumference is an indicator of skeletal muscle mass, while skin fold thickness is proportional to body fat levels. In addition, general physical examination may reveal signs of malnutrition in the skin, nails, hair, teeth and mucous membranes. 

Mahler, D.T., Scott, A.S., Walsh. J.R. and Haynic, G. (1970). A study of trace metals in finger nails and hair using neutron activation analysis. J.Nucl. Med. 11,739-742 Malik. S.R. and Fremlin, J.H. (1974). A study of lead distribution in human teeth using charged particle activation analysis. Caries Res. 8, 283-292 Manly, R.S. and Hodge, H.G. (1939). Density and refractive index studies of dental hard tissue, J. Dent. Res. 18,133-141... 

Rockwell hardness (index 80) was enough for the teeth therefore, improved hardness could be attained by EB irradiation without any mixing of hardening materials. As the wear resistance increased by about 40%, the life could be extended to twice or so. 

England Institute of Child Health/ Southampton Study London 6 years old (402) Urban community exposures Pb indexed by three Pb ranges in shed teeth (crowns) Significant negative Pb-teeth versus IQ relationship in boys but not girls Pocock et al. (1989)... 

Lies, II, M.A. and M. Newman. OSHA Whistleblower Protection Giving Sharper Teeth to a Legal Dinosaur. At http //www.cdworldmag.com/index. php/news/guest-commentary/166-osha-whistleblower-protection-giving-sharper-teeth-to-a-legal-dinosaur.html... 

Toothpaste Sorbitol is used in toothpastes for three reasons as a sweetener, as a humectant, and as an emulsifier. It has a low glycemic index and is safe for teeth (it is not metabolized by oral bacteria), and because of that most toothpastes contain D-sorbitol or glycerin (or both) as humectants. Its sweetness is not as intense as desired by consumers so many producers add saccharin to increase the sweet taste, achieving a final combination that... 

The use of lead in mineralizing tissue, especially in teeth, as a biological indicator of lead exposure is based on the accumulation of the toxicant in these matrices as a function of both age and level of exposure. Hence, lead in teeth or bone provides a cumulative index of exposure over very extended time frames. Lead levels in shed teeth as an exposure indicator have been employed in a number of studies of the effects of lead on paediatric populations (e.g., Needleman et al, 1979 Delves et al, 1982 Ewers et al, 1982 Grandjean et al, 1984). Elevated levels of the element have been reported in whole teeth or their constituents as a function of poisoning history, point source proximity, or geographical location (Shapiro et al, 1973 Needleman et al, 1979 Steenhout and Pourtois, 1981 Ewers et al, 1982 Delves et al, 1982 Grandjean et al, 1984). 

In summary, the use of shed dentition as a biological indicator of cumulative exposure to lead in children would appear to be appropriate under certain conditions. These conditions include rigorous steps to minimize variance in the measure multiple tooth sampling restricted to the same type (and location if possible), or use of concordance criteria for acceptance or rejection of lead levels in replicate sampling. By its nature, measurement of lead in teeth is a retrospective index of exposure to lead, and this measure is not as inherently useful for regulatory policy or clinical intervention/management of lead exposure and intoxication as is PbB. The various prospective studies currently under way in different countries for lead exposure/effects in children include some that utilize serial measurement of PbB in the paediatric subjects as they develop. Comparison of these multiple measurements with lead in shed dentition in the future would be valuable in establishing blood lead-tooth lead relationships. 

---