TF Index Research Articles

The Prevalence and Severity of Fluorosis in Children Who Received Toothpaste Containing either 440 or 1,450 ppm F from the Age of 12 Months in Deprived and Less Deprived Communities

This study compared fluorosis in the upper central incisors of children from socially diverse backgrounds who had received either 440- or 1,450-ppm F toothpaste from 12 months of age. The children were resident in non-fluoridated districts in the north-west of England. They received either 440- or 1,450-ppm F toothpaste and advice regarding its use until the age of 5–6 years. Dental fluorosis (TF index) was assessed on digital images of dried teeth when the children (n = 1,268) were 8–10 years old. In the less deprived districts the prevalences of fluorosis (TF ≧0) for the 1,450- and 440-ppm F groups were 34.5 and 23.7% (p = 0.006). In the deprived districts the prevalences of fluorosis were 25.2 and 19.5% (p = 0.2). Overall the prevalences of TF ≧2 were 7 and 2.1% for the 1,450- and 440-ppm F groups and 2.2 and 0.2% for TF ≧3. These differences were statistically significant (p < 0.003). There was a strong association between the deprivation status of wards and fluorosis. Only 1 subject with a TF score of 3 was identified in the two most deprived quintiles of the Townsend score. It is concluded that careful targeting of programmes of this type to children living in high caries risk deprived communities carries only a small risk of aesthetically objectionable fluorosis (TF >2) whether low or high fluoride toothpastes are used. High fluoride (1,450 ppm F) toothpastes should not be provided on a community basis to very young children in less deprived communities.

Enamel Fluorosis Prevalence after a 7‐year Interruption in Water Fluoridation in Jaú, São Paulo, Brazil

This paper analyzes the impact of a 7-year interruption in water fluoridation on the prevalence of enamel fluorosis in Jaú, state of São Paulo, Brazil. Fluorosis prevalence (TF index) was evaluated in permanent maxillary central incisors of children (9-14 years old) that were 36 (n=81; cohort -36), 27 (n=81; cohort -27), and 18 months old (+/-1 month; n=89; cohort -18) in October 1991, when the breakstarted, and 18months old(+/-1 month;n=70; cohort 18) after that date. Children brushed their teeth prior to examination, which was conducted under natural light by three calibrated examiners (agreement 87.8-93.8%, kappa 0.72-0.85). The fluorosis prevalence (TF> or =1) was 7.41 percent, 3.70 percent, 7.87 percent, and 18.57 percent, respectively, for cohorts -36, -27, -18, and 18. The difference between cohort 18 and the other groups was statistically significant (Kruskall-Wallis test, P=.05). These results suggest that the fluoridated water is not an important risk factor for enamel fluorosis, since the prevalence of enamel fluorosis was low in the cohorts -36, -27, and -18 when fluoridated water was used.

A standardized photographic method for evaluating enamel opacities including fluorosis.

The objective of this study was to demonstrate the reproducibility of a standardized photographic technique for recording fluorosis when used by a group of epidemiologists as part of a large multicentred European study. Studies were first carried out to develop the equipment specification and photographic method. The author (JAC) was then trained and calibrated in this method. She was then responsible for the training and calibration of examiners from a further six European study sites. The method involved taking two transparencies of the permanent maxillary central incisors of 8-year-old children, the first after 8 s while the teeth were still wet and the second after 105 s when the teeth had been allowed to dry out naturally. Data were collected at a central location during a training/calibration exercise and subsequently, during the conduct of a large study to measure fluorosis prevalence, at the seven sites. Intra- and interexaminer reproducibility of the photographic method were measured by grading the transparencies produced by all the examiners according to the DDE and TF indices. The time period in which the transparencies were taken was to within 4 s among the examiners. Transparencies scored according to the TF index gave a range of Kappa values of 0.45-0.66 for intraexaminer reliability and 0.32-0.55 for interexaminer reliability. When using the DDE index Kappa values ranged from 0.43 to 0.70 for intraexaminer reliability and from 0.34 to 0.69 for interexaminer reliability. The photographic method was mostly robust and reproducible when used by epidemiologists from seven European study sites.

Fluorosis development in seven age cohorts after an 11-month break in water fluoridation.

This study used an 11-month break in water fluoridation to identify the time when developing incisors are most sensitive to fluorosis development. The study was based in Durham, NC, where an interruption to water fluoridation occurred between September, 1990, and August, 1991. A total of 1896 children was dentally examined. Fluorosis was measured by the TF index, and parents or guardians completed a questionnaire on demographics and fluoride history. Age cohorts ranged from those born 5 years before the break, to those born 1 year after the resumption of fluoridation. Fluorosis prevalence for seven age cohorts whose birth years ranged from 1985-86 to 1991-92 was 57.1, 62.3, 33.0, 32.3, 39.8, 30.2, and 36.8%, respectively. Children aged from birth to 3 years at the break, and those born 1 year after it, had less fluorosis than those aged 4-5 years at the break.

Dental fluorosis decline after changes to supplement and toothpaste regimens.

In 1989/90, in 659 12-year-olds in Perth (F 0.8 mg/L) and the Bunbury region of Western Australia (WA) (F approximately 0.25 mg/L), dental fluorosis prevalences were 40.2% and 33.0%. Fluoride supplements (OR 4.63) and extended residence in a fluoridated area (OR 4.06) were significant risk factors; toothpaste ingestion variables had ORs greater than unity; in 1990, DMFT for this age group was 0.84. School Dental Service took steps to discourage supplement and toothpaste ingestion and to promote low fluoride toothpaste for children < 6 years of age. To evaluate the effect of this campaign on fluorosis and caries. Between May-July 2000, 582 10-year-olds were examined for dental fluorosis (TF index) and dental caries (DMFT) in school dental clinics. Fluorosis prevalence was 22.2% in Perth and 10.8% in the Bunbury region. Overall prevalence was 18.0% and of this, 80.2% was TF 1, 17.9% was TF 2 and just 1.9% was TF 3. In 1989/90, 79 children had used supplements before the age of 4 year; in 2000 only 40 had done so (P < 0.001). Mean DMFT values in Perth and Bunbury were 0.32 and 0.28 (P > 0.05). Low F toothpaste, unavailable in 1989/90, had been used by 24.5%. The only significant risk factor was residence, OR 2.0. Fluorosis prevalence seems to have fallen in parallel with a reduction in discretionary intake from supplements and toothpaste. No increase in dental caries experience was recorded. Because the teeth examined in this study were at risk of fluorosis in 1992-95, very soon after policies changed, and because people are slow to change health habits, it seems reasonable to expect a further improvement when teeth mineralised in the late 1990s become visible.

Risk periods in the development of dental fluorosis.

In order to study the age-related susceptibility to dental fluorosis, 40 children who had been lifelong consumers of moderate- to high-fluoride water (0.55-8.48 mg F/l) were examined, as well as a group of older siblings (n = 40) who were born 6 months to 6 years before the fluoride-containing drinking water was introduced to the household. Background information was obtained through a structured questionnaire. Dental fluorosis was scored according to the TF index. Among the 80 children examined, the permanent incisors were erupted in 66, while 67 had permanent first molars present. As compared to their older siblings, the prevalence of dental fluorosis was significantly higher in the children who had consumed moderate-to high-fluoride water throughout their lives. In a multiple regression analysis, the variable "age when introduced to moderate- to high-fluoride water" came out as the only significant risk factor associated with dental fluorosis. This variable was divided into three categories according to the first exposure to moderate- to high-fluoride drinking water (1) 0-12 months of age, (2) 13-24 months of age and (3) after 24 months of age. Category 3 was used as the reference group. Fluoride exposure starting during the 1st year of life showed the highest odds ratio as compared to exposure only after 2 years of age. The findings indicate that early mineralizing teeth (central incisors and first molars) are highly susceptible to dental fluorosis if exposed to fluoride from the first and--to a lesser extent--also from the 2nd year of life.

Dental Fluorosis and Nutritional Status of 6– to 11–Year–Old Children Living in Rural Areas of Paraíba, Brazil

The aim of this study was to investigate the relationship between nutritional status and dental fluorosis in areas with fluoride in the drinking water in Paraíba, Brazil. Rural villages of comparable low socio–economic status and stable water fluoride levels were selected. Lifelong residents (6–11 years old, n = 650) were examined for nutritional status (height–for–age index; WHO methods) and dental fluorosis of central incisors and first molars (TF index). The sample was divided into three groups according to fluoride levels in the drinking water: low (below 0.7 ppm F, n = 164), medium (between 0.7 and 1.0 ppm F, n = 360) and high (above 1.0 ppm F, n = 126). Dental fluorosis was observed in 30.5, 61.1 and 71.4% of the children in these F groups, respectively. The prevalence was significantly related to the water F concentrations (χ² = 59.93, d.f. = 2, p<0.001). The severity of dental fluorosis ranged from TF 1 to 3 in the low F group and up to 7 in the others. Malnutrition prevalence was approximately 20% in all F groups, but was unrelated to dental fluorosis. The fairly high prevalence of dental fluorosis observed suggests that other factors may be operating.

Fluorosis risk from early exposure to fluoride toothpaste.

Swallowed fluoride toothpaste in the early years of life has been postulated to be a risk factor for fluorosis, but the epidemiological evidence is weakened by the fact that most of the relevant studies were done in developed countries where an individual is exposed to multiple sources of fluoride. To quantify the risk of fluorosis from fluoride toothpaste in a population whose only potential source of fluoride was fluoride toothpaste. Case-control analyses were conducted to test the hypothesis that fluoride toothpaste use before the age of 6 years increased an individual's risk of fluorosis. Data came from a cross-sectional clinical dental examination of schoolchildren and a self-administered questionnaire to their parents. The study was conducted in Goa, India. The study group consisted of 1189 seventh grade children with a mean age of 12.2 years. The prevalence of fluorosis was 12.9% using the TF index. Results of the crude, stratified, and logistic regression analyses showed that use of fluoride toothpaste before the age of 6 years was a risk indicator for fluorosis (OR 1.83, 95% CI 1.05-3.15). Among children with fluorosis, beginning brushing before the age of 2 years increased the severity of fluorosis significantly (P<0.001). Other factors associated with the use of fluoride toothpaste, such as eating or swallowing fluoride toothpaste and higher frequency of use, did not show a statistically significant increased risk for prevalence or severity of fluorosis. Fluoride toothpaste use before the age of 6 years is a risk indicator for fluorosis in this study population.

Enamel opacities and dental esthetics.

The purpose of this study was to determine the esthetic importance of different types of developmental enamel defect. In the first method used, individual subjects from three different populations with less than 0.1, 0.7, and 0.9 ppm fluoride in their drinking water, were asked about the appearance of their teeth and results compared to assessments of clinical photographs made by a single examiner. In the second method used, dentist and lay observers were asked to assess the appearance of the dentition of selected individuals who had a range of enamel defects. According to the first method, both the size of demarcated opacities and the degree of enamel hypomineralization (TF index) were related to satisfaction with appearance. However, there was no difference in satisfaction with the appearance of the teeth among the three areas included in this study. In the second method, similar types of enamel defects were found to be esthetic stimuli as with the first study, but the dentists responded more strongly to the stimulus of enamel hypomineralization than the lay examiners. Both demarcated opacities and enamel hypomineralization may be important when assessing differences between populations. Further, esthetic ratings by dentists may not be a suitable means of assessing the esthetic importance of different types of enamel defects.

Dental Tissue Effects of Fluoride

It is now well-established that a linear relationship exists between fluoride dose and enamel fluorosis in human populations. With increasing severity, the subsurface enamel all along the tooth becomes increasingly porous (hypomineralized), and the lesion extends toward the inner enamel. In dentin, hypomineralization results in an enhancement of the incremental lines. After eruption, the more severe forms are subject to extensive mechanical breakdown of the surface. The continuum of fluoride-induced changes can best be classified by the TF index, which reflects, on an ordinal scale, the histopathological features and increases in enamel fluoride concentrations. Human and animal studies have shown that it is possible to develop dental fluorosis by exposure during enamel maturation alone. It is less apparent whether an effect of fluoride on the stage of enamel matrix secretion, alone, is able to produce changes in enamel similar to those described as dental fluorosis in man. The clinical concept of post-eruptive maturation of erupting sound human enamel, resulting in fluoride uptake, most likely reflects subclinical caries. Incorporation of fluoride into enamel is principally possible only as a result of concomitant enamel dissolution (caries lesion development). At higher fluoride concentrations, calcium-fluoride-like material may form, although the formation, identification, and dissolution of this compound are far from resolved. It is concluded that dental fluorosis is a sensitive way of recording past fluoride exposure because, so far, no other agent or condition in man is known to create changes within the dentition similar to those induced by fluoride. Since the predominant cariostatic effect of fluoride is not due to its uptake by the enamel during tooth development, it is possible to obtain extensive caries reductions without a concomitant risk of dental fluorosis.

Dental Fluorosis, Dental Caries and Fluoride Exposure among 7-Year-Olds

Mild dental fluorosis is frequently linked to fluoridated water, but discretionary fluoride sources may also be important. The aim of this study was to record age of weaning and fluoride exposure from water, toothpaste and supplements, and to relate these to the presence of caries and fluorosis in children born in 1983. In Perth (Western Australia) 14 school classes were selected. The 350 children (mean age 7.5 years) ultimately included gave fluoride exposure data for the period birth to 4 years of age. Caries (DMFT, WHO criteria, no radiographs) and dental fluorosis (TF index, dry permanent incisors) were registered clinically. Most (89%) children had lived at least 2.5 years in a fluoridated area. Supplement use was minimal and unrelated to caries or fluorosis. Mean age of weaning of those who had been breast-fed was 7.7 months; by 9 months, 74% had been weaned. Eighty-five percent liked toothpaste, 60.7% had swallowed it, and the mean age of starting to use it was 1.5 (SD 0.96) years. Caries prevalence was 0.1 and mean DMFT was 0.13. The prevalence of fluorosis was 0.48; 63% of fluorosis was TF score 1. Residence in a fluoridated area for > or = 2.5 of the first 4 years of life had an odds ratio (OR) of 4.9 for fluorosis. Weaning before 9 months of age, swallowing toothpaste and liking toothpaste were also statistically significant risk factors. Major risk factors for more severe fluorosis (TF > or = 2) were early weaning and swallowing toothpaste (ORs 2.77 and 2.64, respectively). Residence in a fluoridated area (OR 2.2) was not a statistically significant risk factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Fluoride concentrations in unerupted fluorotic human enamel.

Unerupted fluorotic human enamel was obtained from teeth surgically removed from patients with dental fluorosis. Fluoride was measured in samples produced by serial acid etching from the surface to the interior of blocks of buccal and lingual enamel. The severity of fluorosis, according to the TF index, was determined from the macroscopic and microradiographic appearance of the specimens. The shape of the fluoride profiles was not affected by the degree of severity of fluorosis, but the fluoride concentrations increased with increasing severity of lesions. Fluoride concentrations were similar to those previously recorded in erupted fluorotic enamel and were not related to the length of time the teeth had been present in the jaws. It was concluded that the fluoride content of erupted fluorotic enamel represents fluoride acquired during tooth formation and that further uptake prior to eruption may be negligible.

The Nature and Mechanisms of Dental Fluorosis in Man

Any use of fluorides, whether systemic or topical, in caries prevention and treatment in children results in ingestion and absorption of fluoride into the blood circulation. The mineralization of teeth under formation may be affected so that dental fluorosis may occur. Dental fluorosis reflects an increasing porosity of the surface and subsurface enamel, causing the enamel to appear opaque. The clinical features represent a continuum of changes ranging from fine white opaque lines running across the tooth on all parts of the enamel to entirely chalky white teeth. In the latter cases, the enamel may be so porous (or hypomineralized) that the outer enamel breaks apart posteruptively and the exposed porous subsurface enamel becomes discolored. These changes can be classified clinically by the TF index to reflect, in an ordinal scale, the histopathological changes associated with dental fluorosis. Compared with Dean's and the TSIF index, we consider the TF index to be more precise. Recent studies on human enamel representing the entire spectrum of dental fluorosis have demonstrated a clear association between increasing TF score and increasing fluoride content of the enamel. So far, no useful data on dose (expressed in mg fluoride/kg b.w.)-response (dental fluorosis) relationships are available. In this paper, we have, therefore, re-evaluated the original data by Dean et al. (1941, 1942), Richards et al. (1967), and Butler et al. (1985) from the USA, by applying the equation of Galagan and Vermillion (1957) which permits the calculation of water intake as a function of temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of carbohydrate-deficient transferrin compared with Tf index and other markers of alcohol abuse.

It has been known for some years that a partial deglycosylation of transferrin occurs in the sera of alcohol abusers. Different methods have been proposed in order to evaluate this carbohydrate-deficient fraction of serum transferrin. Chromatofocusing or isoelectric focusing followed by direct immunofixation have been used until now. Recently, a new method called the carbohydrate-deficient transferrin (CDT) test based on ion-exchange chromatography has been developed by Stibler et al. (Alcohol Clin Exp Res 10:535-544, 1986). Here we compare this new method with results obtained using our Tf index determination method. The upper limit of normal values was set to the 90th percentile of the values observed in a reference population. The population under investigation consisted of 50 healthy volunteers and 160 alcohol abusers whose ethanol consumption was evaluated through a questionnaire. Sensitivity and specificity of the CDT test have been found higher than 0.76 and 0.90, respectively. The correlation between both methods was 0.794, a satisfactory result considering that the CDT test and the Tf index do not exactly measure the same part of the carbohydrate-deficient transferrin. In a population of 23 patients with liver diseases not related to alcohol abuse, no abnormal CDT value was observed. We can conclude from these results that the CDT test now seems to be the best test to detect alcohol abusers.

Enamel fluoride in relation to severity of human dental fluorosis.

The aim of this study was to test whether the concentrations of fluoride in fluorotic human enamel are related to the degree of severity of dental fluorosis classified according to the index described by Thylstrup and Fejerskov. Teeth representing the entire spectrum of human dental fluorosis were analyzed. Fluoride concentrations were determined by serial acid-etching from surface to interior of blocks of enamel cut from each tooth. Fluoride was measured by ion electrode and calcium by atomic absorption spectrophotometry. The results showed that the pattern of distribution of fluorotic enamel is similar to that described for normal enamel. Increasing severity of fluorotic lesions was associated with increasing concentrations of fluoride throughout the enamel. It is concluded that although further studies are required to establish the relative contribution of fluoride which may be taken up posteruptively by fluorotic enamel, the findings support the hypothesis that the TF index reflects increasing exposure to fluoride during tooth development.

Assessment of the Transferrin Index in Screening Heavy Drinkers from a General Practice

The aim of this study was to assess the performance of the transferrin (Tf) index in screening heavy drinkers and to compare its performance to that of gamma glutamyl transpeptidase (GGT). Tf index, GGT, and transaminase activities were determined in a group of 173 subjects (49% males) recruited in a family doctor's practice (age: 54 +/- 1.5 yr; daily alcohol intake: 32 +/- 3.5 g; mean +/- SEM). Tf subfractions were quantified by isoelectric focusing and immunofixation on polyacrylamide gel. The Tf pl 5.7 to 5.4 ratio, or Tf index, was used as a marker of excessive drinking, with a cut-off point at 7%. Alcohol consumption was assessed through a face-to-face interview. Excessive drinkers were defined as those with a daily alcohol intake greater than 80 g over at least 2 years; 20 were classified as excessive drinkers (alcohol consumption: 92-232 g/day). All but four had normal transaminase activities indicating the low prevalence of hepatic impairments in this sample. The Tf index was found to have a sensitivity of 45%, specificity 89%, positive predictive value 35%, negative predictive value 92%. The corresponding results for GGT were 52%, 80%, 27%, and 92%, respectively. Concordance between the Tf index and GGT was assessed by the kappa coefficient (kappa) which was 0.22 indicating poor agreement between the two markers in selecting excessive drinkers (perfect association: kappa = 1, no association: kappa = 0).

Serum desialotransferrin in the detection of alcohol abuse. Definition of a Tf index

Different molecular forms of transferrin (Tf) have been separated in sera from alcoholics and controls by isoelectric focusing on ultrathin polyacrylamide gels using a semi narrow pH range. The main fraction focused at pH 5.4 (Tf5.4) and minor components appeared among controls at pH 5.7 (Tf5.7). This fraction was increased among alcoholics and was sometimes accompanied by a fraction focusing at pH 5.9 (Tf5.9). Fractions were quantified by densitometry following immunofixation. Significant differences in the ratios Tf5.4 Tf and Tf5.7 Tf between the groups were obtained, but no difference could be determined in the total Tf. We used the ratio Tf5.7 Tf5.4 called Tf index to distinguish alcoholics from controls. The sensitivity, the specificity and the global predictive value of this test were 0.82, 1 and 0.88 respectively. These results seems to indicate that the Tf index is more reliable for the detection of alcohol abuse than liver enzymes such as gammaglutamyl transferase (γGT) or glutamate dehydrogenase (GDH).

Quantification of body fat distribution in the abdomen using computed tomography

A computed tomographic method was used to assess the pattern of abdominal fat distribution in normal males and females at different abdominal levels. The method permitted site specific calculations of total body volume (TA), total fat volume (TF), subcutaneous fat volume (SF), and intraabdominal fat volume (IF) in each computed tomography scan. The ratio of TF/TA, SF/TF and IF/TF were calculated for the LI, L3, and L5 vertebral levels. Regression analysis of IF versus SF, SF versus TF, IF versus TF, TF versus TA, and TF versus body mass index and age were calculated. A significant linear correlation between the measured variables TA, SF, IF, and TF and between TF and body mass index was found for virtually all correlations attempted at all scanned levels. Females had a higher total fat volume and greater percentage of subcutaneous fat at all levels. Males accumulated more fat intraabdominally than subcutaneously at the L1 and L3 levels. The male-female differences were greatest at L1 and the ratio SF/IF statistically significant at the L1 and L5 levels. Our results demonstrate that computed tomography can noninvasively quantify abdominal fat distribution at various sites. There is an inherent difference in abdominal fat distribution between males and females that is not related to weight. The distribution of body fat in males and females varies markedly from level to level.