High Fluoride Areas Research Articles

Thoracic ossification of ligamentum flavum caused by skeletal fluorosis.

Thoracic ossification of ligamentum flavum (OLF) caused by skeletal fluorosis is rare. Only six patients had been reported in the English literature. This study reports findings from the first clinical series of this disease. This was a retrospective study of patients with thoracic OLF due to skeletal fluorosis who underwent surgical management at the authors' hospital between 1993 and 2003. Diagnosis of skeletal fluorosis was made based on the epidemic history, clinical symptoms, radiographic findings, and urinalysis. En bloc laminectomy decompression of the involved thoracic levels was performed in all cases. Cervical open door decompression or lumbar laminectomy decompression was performed if relevant stenosis was present. Neurological status was evaluated preoperatively, at the third day postoperatively, and at the end point of follow-up using the Japanese Orthopaedic Association (JOA) scoring system of motor function of the lower extremities. A total of 23 cases were enrolled, 16 (69.6%) males and 7 (30.4%) females, age ranging from 42 to 72 years (mean 54.8 years). All patients came from a high-fluoride area, and 22 (95.7%) had dental fluorosis. Medical imaging showed OLF together with ossification of many ligaments and interosseous membranes, including interosseous membranes of the forearm (18/23 patients 78.3%), leg (14/23 patients 60.9%), and ribs (11/23 patients 47.8%). OLF was classified into five types based on MRI findings: localized (4/23 patients 17.4%), continued (12/23 patients 52.2%), skip (3/23 patients 13.0%), combining with anterior pressure (2/23 patients 8.7%), and combining with cervical and/or lumbar stenosis (2/23 patients, 8.7%). Urinalysis showed a markedly high urinary fluoride level in 14 of 23 patients (60.9%). Patients were followed up for an average duration of 4 years, 5 months. Paired t-test showed that the JOA score was slightly but nonsignificantly increased relative to preoperative measurement 3 days after surgery (P = 0.0829) and significantly increased at the end of follow-up (P = 0.0001). In conclusion, Fluorosis can cause ossification of thoracic ligamentum flavum, as well as other ligaments. Comparing with other OLF series, a larger number of spinal segments were involved. The diagnosis of skeletal fluorosis was made by the epidemic history, clinical symptom, imaging study findings, and urinalysis. En bloc laminectomy decompression was an effective method.

Sociodemographic and behavioural correlates of severe dental fluorosis

The aim of this study was to identify sociodemographic and behavioural factors associated with the prevalence of severe dental fluorosis in moderate- and high-fluoride areas of the Ethiopian Rift Valley. Three hundred and six adolescents (12-15 years) and 233 mothers participated in the study. The children were examined for dental fluorosis according to the Thylstrup-Fejerskov Index (TFI). The children and their mothers were subsequently interviewed. Sixty mothers had more than one participating child. In order to perform a paired parent/child analysis, a total of 73 younger siblings had to be excluded. Among the remaining 233 children, the prevalence of severe dental fluorosis (TFI >or= 5) was 24.1% and 75.9% in the moderate- and high-fluoride areas, respectively. According to bivariate as well as multivariate analyses, a number of sociodemographic and behavioural factors were related to severe fluorosis. The odds for having severe fluorosis varied according to the fluoride concentration of the drinking water, age, consumption of tea, length of breastfeeding and method of storing water. The adjusted odds ratios ranged from 2.6 to 26.1. Breastfeeding for > 18 months and the use of clay pots for storing drinking water helped protect against severe dental fluorosis. Bivariate analyses indicated that being male and consuming fish might be associated with higher TFI scores. In order to avoid dental fluorosis, low-fluoride drinking water should be provided in the relevant villages. A prolonged period of breastfeeding, the use of clay pots for storing water, and possibly a reduced intake of tea and whole fish in infants might also help to avoid severe fluorosis in children growing up in traditionally fluoride-endemic areas.

Dental fluorosis and dental caries in permanent teeth: rural schoolchildren in high-fluoride areas in the Shaanxi province, China

Objectives. To study the dental fluorosis and caries in the permanent teeth of 12 to 13-year-old children in fluorosis-endemic areas; to assess the relationship between fluorosis and the fluoride content of the drinking water and the relationship between caries and the fluoride content of the water; finally, to analyze the effect of fluoride intake and water stored in clay pots on dental fluorosis. Material and methods. 477 children were divided into 5 groups (A to E) according to the fluoride concentration of the waters, i.e. by 0.4, 1.0, 1.8, 3.5, and 5.6 mg F/l, respectively. Dental fluorosis was assessed by TF score and caries by the DMF-T index. A questionnaire was used to obtain information about water storage and other information relevant to children's fluoride intake. Results. A positive relationship was found between the mean TF scores and the water fluoride concentration. In groups B and D, the TF score was higher in 13-year-olds than in 12-year-olds. Caries prevalence and mean DMF-T ranged from 2.6% and 0.03 (group E) to 22.1% and 0.38 (group A). Storage of water in clay pots seemed to increase the severity of fluorosis slightly, and to decrease the caries prevalence. Conclusions. Defluoridation of drinking water, or—alternatively—the provision of low-fluoride water sources, should be given high priority in the examined Shaanxi rural areas. Fluoride concentration of drinking water should be maximum 0.6 mg/l. Storage of water in the local clay pots may increase the severity of dental fluorosis.

Effects of Selenium, Copper and Magnesium on Antioxidant Enzymes and Lipid Peroxidation in Bovine Fluorosis

The antioxidant enzymes, lipid peroxidation and free radicals assessment were made of the effects of selenium, copper and magnesium on bovine endemic fluorosis under high fluoride, low selenium and low copper productive conditions. Thirty-two beef cattle were selected from high fluoride area, and randomly divided into four groups with eight cattle each as follows: (1) high fluoride control group (HFC); (2) supplemented group with 0.25 mg/kg selenium (HFSe); (3) supplemented group with 15 mg/kg copper (HFCu) and (4) supplemented group with 0.25 mg/kg selenium+15 mg/kg copper+1 mg/kg magnesium (HFSeCuMg) per day for 83 days. Moreover, eight beef cattle were selected from non-high fluoride area as normal control group. Blood samples were collected from cattle on 0 d, 30 d and 83 d respectively, to analyze the enzyme activities and concentration of GSH-px, CAT, SOD, MDA and free radicals. The results showed that the contents of free radicals and MDA in HFC group were significantly higher, and the whole blood GSH-px, CAT, erythrocyte SOD activities were lower than the normal control group. Free radicals, metabolic imbalance and antioxidant disorder therefore, play an important role in fluorosis. However, GSH-px, CAT and SOD activities in HFSe group and HFSeCuMg group at 30 d and 83 d were markedly higher than the same groups at the 0 d and the HFC group at the same time. Likewise, there was a corresponding reduction in the contents of free radicals and MDA. These findings indicated that supplementation with selenium, copper and magnesium elevated high fluoride bovine antioxidant enzymes, and decreased MDA and free radicals contents. But, the activities of supplementation selenium group did not increase until day 83. These results demonstrated that fluorosis was associated with lower serum Se and Cu levels than in the control, and it was therefore concluded that fluorosis is associated with decreased serum levels of these minerals. Long-term high fluoride intake under productive condition enhances oxidative stress in the blood, thereby disturbing the antioxidant defense of cattle. Increased oxidative stress could be one of the mediating factors in the pathogenesis of toxic manifestations of fluoride. It is benefical for high fluoride cattle supplemented with proper selenium, copper and magnesium to increase fluoride excretion and obtain the protective impact of the activity of oxidative enzymes, and to decrease lipid peroxidation and free radicals contents.

Dental Caries and Developmental Defects of Enamel in Relation to Fluoride Levels in Drinking Water in an Arid Area of Sri Lanka

The study was conducted to assess caries and developmental defects of enamel in relation to fluoride levels in drinking water and the association between caries experience and the severity of diffuse opacities in children living in Uda Walawe, an area with varying concentrations of fluoride in drinking water in Sri Lanka. A total of 518 14-year-old children who were lifelong residents in this area were examined for dental caries and developmental defects of enamel. But the present analysis is confined to 486 children from whom drinking water samples were collected. The prevalence of enamel defects and diffuse opacities ranged from 27 to 57% while the prevalence of caries ranged from 18 to 29% in the different fluoride exposure groups. The prevalence of enamel defects increased significantly with the increase in the fluoride level in drinking water. Both the caries prevalence and the mean caries experience were significantly higher in children with diffuse opacities than in those without in the group consuming water containing >0.70 mg/l of fluoride. The association between dental caries and the severity of diffuse opacities was also significant only in this group. Children with the mildest form of opacities (DDE scores 3 and 4) had the lowest DMFS (0.25 ± 0.7), and the highest DMFS (1.1 ± 1.7) was found in those with the most severe form of opacities (DDE score 6). In conclusion, the relationship that was observed in this study between fluoride levels in drinking water, diffuse opacities and caries suggests that the appropriate level of fluoride in drinking water for arid areas of Sri Lanka is around 0.3 mg/l. Also individuals with severe forms of enamel defects in high-fluoride areas are susceptible to dental caries.

Enamel mottling in a group of Iraqi students in a high and low fluoride community

The purpose of the study was to determine the prevalence of mottled enamel in a group of school students lived in area with high and low natural fluoride contained drinking water in Iraq. The study was conducted among (874) school's students aged (13-16) years from randomly selected intermediate schools in two provinces in Ninevah Governorate, Tour hundred and eight students who had lived since birth in high natural fluoride level area (Sinjar province) (2.05-2.22 ppm fluoride) and (466) students lived continuously from birth in low natural fluoride level area in their drinking water (Talkaif province) (0.11-0.19 ppm fluoride). Al-Alousi index has been used to assess mottled enamel. The results show that the prevalence of mottledenamel in Sinjar province is (95.8%) within individuals and (65.3%) within teeth, with significant difference between the sex; while the prevalence of mottled enamel in Talkaif province was (18.1%) within individuals and (3.6%) within teeth, with no significant sex difference. The high percentage of mottled channel was of type "A", followed by types "B" and "E" in high fluoride area, while in low fluoride area also type "A" reported thehigh prevalence, followed by types "B" and "C".

Plaque minerals in the prediction of caries activity

Attempts to identify subjects who will develop caries lesions in future years have been only moderately successful, suggesting that one or more important risk factors are being overlooked. The aim of this study was to validate the use of plaque calcium, phosphate and fluoride concentrations as significant risk factors in caries. DMFS and DMFT rates were measured three times over 2 years in a group of rural Chinese schoolchildren initially aged 12 years and not living in a high-fluoride area. At the baseline and year 1 examinations, dental plaque was accumulated for 3 days and, after collection, was analysed for Ca, P and F. Plaque scores, dental health behaviour and parents' occupation data were also recorded. The mean DMFS increment over 2 years was 1.14 with a range of -2 to +9. Regression analysis taking all factors into account identified only plaque Ca concentration, baseline DMFS score and toothbrushing frequency as significant factors in identifying high-risk individuals. Plaque Ca also showed predictive ability on its own. For example, when high caries was defined as 3+ new DMFS and a Ca cut-off value of 200 nmol/mg dry wt was selected, sensitivity was 0.84 and specificity 0.38. However, with this cut-off value the percentage predicted to have high caries risk was unrealistically high at 66%. As in several other studies, baseline caries score was a useful predictor of future caries. Low plaque Ca concentration showed a modest ability to predict future caries, and since it is implicated directly in the chain of events leading to caries, its use in caries prediction should be considered further. Plaque P and F showed no predictive ability in this study.

Sources of dietary fluoride intake in 4-year-old children residing in low, medium and high fluoride areas in Iran

Accurate estimation of fluoride dietary intake is desirable for optimising caries prevention. Little is known about the dietary fluoride intake of children aged 4 years, an age when many permanent teeth are forming. This study was undertaken in Fars Province, Iran, in 1995-96, where there are big differences in temperature between winter and summer. The aims were to determine: (a) the relative contributions of different components of the diet to fluoride intake, (b) the effect of variation in fluoride concentration in drinking water, and (c) the effect of climate temperature. Temperature varied between +40°C in summer to -5°C in winter. The mean fluoride concentrations in drinking water in the three areas were 0.3, 0.6 and 4.0 mgF/L. Dietary information was obtained by two 3-day diet diaries with interview, validated with reference to international standards. The fluoride content of foods was measured using the silicon-facilitated diffusion method. One hundred and three 4-year-old children completed the study. The mean (and 95% confidence interval) dietary fluoride intakes in each of the three areas, respectively, were 413 (± 21), 698 (± 89) and 3472 (± 557) μ g/day. Drinks provided 72 to 87% of dietary fluoride - this proportion increased with increasing water fluoride concentration and increasing climate temperature. Tea (infusion) was an important source of dietary fluoride, providing 31 to 38% of total dietary intake. Tap water was a more important source of fluoride than soft drinks. Cooked rice and bread were the most important food source of fluoride and the amount of fluoride they contributed increased as water fluoride concentration increased. The results of this first such survey in the Middle East showed (a) that water (as a drink) and tea were by far the most important contributors to dietary fluoride intake, (b) substantial increases in fluoride intake with increasing water fluoride concentrations, and (c) substantially higher fluoride intakes in summer than in the winter.

Dental fluorosis and caries incidence in rural children residing in a high fluoride area in the dry zone of Sri Lanka

Dental fluorosis and caries incidence in rural children residing in a high fluoride area in the dry zone of Sri Lanka

Vegetarianism and dental fluorosis among children in a high fluoride area of northern Tanzania.

The purpose of this study was to compare the prevalence and severity of dental fluorosis among vegetarian and nonvegetarian children and adolescents living in an area where dental fluorosis is endemic. An analytical cross-sectional retrospective study. Children (n = 165) aged 6-18 years, from five schools in Arusha town were examined. The children had a life-long exposure to drinking water with 3.6 mg F/litre. The severity of dental fluorosis was assessed using the Thylstrup & Fejerskov Index (TFI). In the vegetarian group (n = 24), the prevalence of dental fluorosis (TFI score > or = 1) was 67%, while 21% had severe fluorosis (TFI score > or = 5). In the nonvegetarian group (n = 141) the prevalence of fluorosis and severe fluorosis was 95% and 35%, respectively. In bi-variate correlation analyses age, vegetarianism and a series of other factors related to childhood nutrition (meals per day, the use of home-made porridge, the use of fish, etc.) were significantly associated with the tooth prevalence of dental fluorosis (TPF, P < 0.05). Stepwise multiple linear regression analyses explained 30% of the variance in TPF; age 15% points and vegetarianism 13% points. Multiple logistic regression analysis showed that the risk of developing dental fluorosis was seven times higher among nonvegetarians than among vegetarians. The significantly lower prevalence and severity of dental fluorosis among the vegetarian group compared to the nonvegetarians would seem to be related to diet.

Caries and Fluorosis Prevalence in Communities with Different Concentrations of Fluoride in the Water

The need to defluoridate and fluoridate the water supplies in areas with drinking water naturally containing above–optimal (≥2.5 mg/l) and suboptimal (≤0.3 mg/l) fluoride concentration and caries and fluorosis prevalence of 12–year–old schoolchildren were assessed in Italy. In the low–fluoride area, 48.4% children were caries–free (DMFT = 0) and the DMFT and DMFS were 1.5 and 2.6; in the high–fluoride area, 46.8% had a DMFT = 0 and the values of the indices were 1.4 and 1.6, respectively. Multiple logistic regression analysis showed a significant association in the caries–free status according to parents' employment status (OR = 1.2, 95% CI = 1.1–1.3) and children's sweets consumption, since children who consumed sweets at least once a day had an adjusted odds ratio of 1.8 (95% CI = 1.4–2.3) compared to those with a lower consumption. Multiple linear regression analysis showed that DMFT and DMFS were significantly higher in children with a lower socioeconomic status and in those who consumed sweets at least once a day, with the DMFS significantly associated also with the area of residence. DT and FT scores were higher in the high– and low–fluoride areas, respectively. No evidence of fluorosis was reported in 94.5 and 55.3% of children in the low– and high–fluoride areas, respectively. The Community Fluorosis Index (CFI) for all permanent teeth was significantly higher in the high–fluoride area, 0.8, than the value, 0.1, found in the low–fluoride community. Our results substantiate the difficulties in defining universal guidelines for the fluoridation or defluoridation of drinking water and the need for an epidemiological approach to the decision as to fluoridate and defluoridate the water supply.

The interface of nutrition and dentition.

Gross undernutrition in children retards deciduous dental eruption. High fluoride consumption adds to the delay, Exfoliation of teeth is delayed in high fluoride areas. Fluoride has adverse effects on teeth and produces mottling changes and abnormal teeth. Bailey’s formula is not accurate in assessing ages of children in undernourished populations.

Caries and dental fluorosis in a 0.25 and a 2.5 ppm fluoride area in the Sudan.

The purpose of this study was to assess the caries prevalence of children living in areas with either 0.25 or 2.5 ppm fluoride in the drinking water, and to relate caries experience to the severity of dental fluorosis. The children, aged 6-16 years (mean 11.3 years), were lifelong residents of their rural villages. The severity of dental fluorosis in the maxillary central incisors, assessed by Deans index, was 1.4 +/- 0.9 (n = 59) and 2.3 +/- 0.9 (n = 65) in the 0.25 and 2.5 ppm areas, respectively. There was no significant difference in DMFT between children from the two areas (2.6 +/- 2.3 n = 59 versus 2.1 +/- 2.3, n = 65). In the low-fluoride area 75% of the children had decayed permanent teeth compared to 66% in the high-fluoride area. In the primary teeth, however, both the caries prevalence and the dmft were significantly lower in the 2.5 ppm area than in the low-fluoride area. Stepwise, multiple, linear regression analyses, including all children, showed a significant effect of age on DMFT (30% of the variance explained), but no explanatory effect of fluoride in drinking water, severity of dental fluorosis, or gender. Regression analyses based on children in the 2.5 ppm area alone, showed significantly higher DMFT by increased severity of dental fluorosis. In children with a mixed dentition (n = 66), there was no association between caries in the primary and permanent teeth.

Alkali-soluble and insoluble fluoride in erupted and unerupted human enamel from a high fluoride area with a low fluorosis score

The amounts of fluoroapatite and ‘CaF 2-like’ fluoride (F) were determined in enamel of unerupted and erupted teeth that had been exposed in vivo to 1.8–2.6 parts/10 6 F in the drinking water and to brushing with F dentifrice at least once a day, and occasionally to a F mouth-rinse (0.022% F). Enamel was sampled by acid-etching and the F levels were measured with an adapted F ion-selective electrode. More F was built into the deeper enamel in the high-F area than in a similar low-F area. Unerupted enamel did not etch significantly ( p > 0.05) deeper than erupted enamel. No significant differences ( p > 0.05) were found in the F concentrations amongst the following: alkali-washed erupted, unwashed erupted, alkali-washed unerupted and unwashed unerupted at the outer most enamel (approx. 6 μm). However the erupted enamel (alkali-washed or not) showed higher F levels than unerupted enamel (alkali-washed or not) between approx. 6 μm and greater than 100 μm. The increase of F for this high-F area was about 100% in the deeper enamel while for a low-F area it was approx. 78% in the most outer enamel with no increase after a depth of about 20 μm. In contrast to a similar low-F area (water F < 0.10 parts/10 6), no significant ‘CaF 2-like’ F could be detected in erupted or unerupted enamel for the high-F area.

Prediction of caries incidence in schoolchildren living in a high and a low fluoride area

A salivary mutans streptococci test and past caries experience were used as predictors for caries increment in a 3-yr study comprising 655 12-yr-old schoolchildren from two areas with contrasting levels of fluoride in the drinking water. The mean caries (DMFS) increment was similar in both groups during the study period, but a significantly (P < 0.05) higher incidence of approximal enamel lesions was registered in children from the high fluoride area. In both groups, a statistically significant (P < 0.05-0.001) positive relationship between salivary mutans streptococci score and/or past caries experience at baseline on one hand and caries increment during the study period on the other was established. The past caries experience was the most powerful predictor of caries risk in both the low fluoride and the high fluoride area. The sum of the sensitivity and specificity was somewhat higher in the low fluoride area (138%) compared to the high fluoride area (123%). The salivary bacterial enumeration used alone or in combination with past caries experience as well as past approximal caries experience were less useful as predictors in both groups. The present findings indicate that the natural fluoride exposure has a limited influence on caries risk assessment and the caries predictive ability of the salivary bacterial test and past caries in populations with a low level of disease.

Mutans streptococci in saliva and dental caries in children living in a high and a low fluoride area

The aim of this study was to obtain information about the quantitative distribution of salivary mutans streptococci and the relation to dental caries in children with contrasting levels of natural water fluoride. A total of 698 schoolchildren aged 12 yr were selected from areas with high (1.2 ppm) or low (0.1 ppm) fluoride concentration in the drinking water. They were all examined for the presence and number of mutans streptococci in saliva by a specially prepared plastic strip, the "Strip mutans" method, cultivated in a selective broth. Data on the caries experience were obtained from the dental records and from bite-wing radiographs. Mutans streptococci were identified in 82% of all children with no difference between the two areas. The number of mutans streptococci was however significantly (p less than 0.05) lower among the children from the high fluoride area than those from the low fluoride area. Children with no detectable or low levels (0-10 CFU) of mutans streptococci had less caries experience than children with moderate or high levels (11- greater than 500 CFU) in both areas investigated.

Water-borne Fluoride and Cortical Bone Mass: A Comparison of Two Communities

This study investigated the relationship between cortical bone mass in an older female population and their ingestion of fluoride from community water supplies. The study was conducted among lifelong female residents in Lordsburg (3.5 ppm fluoride) and Deming (0.7 ppm fluoride), NM. A total of 151 postmenopausal women ranging in age from 39 to 87 years took part; 69 were residents of the optimal-fluoride community, while the remaining 82 were residents of the high-fluoride community. Although bivariate analyses showed no difference in cortical bone mass between women in the two communities, with multiple regression analyses, significant predictors of bone mass (p less than 0.05) were weight, years since menopause, current estrogen supplementation, diabetes, and fluoride exposure status. Based on a model containing all of these variables, women living in the high-fluoride community had a bone mass ranging from 0.004 to 0.039 g/cm2 less than that of similar women living in the optimum-fluoride community. These results suggest that lifelong ingestion of water containing 3.5 ppm fluoride, compared with water containing 0.7 ppm fluoride, does not increase cortical bone mass in women of similar age, weight, and menopausal status. Under the conditions of this study, cortical bone mass might be reduced in a high-fluoride area.

Diurnal Fluoride Concentration in Whole Saliva in Children Living in a High- and a Low-Fluoride Area

Salivary fluoride concentrations were investigated in 12-year-old children living in areas with low (0.1 ppm) or high (1.2 ppm) fluoride concentration in the drinking water. Unstimulated whole saliva was collected from 27 children from the respective areas every 2nd hour for 46 h except during sleep. The mean salivary fluoride concentration was 0.32 +/- 0.013 mumol/l (n = 419) in the low-fluoride (LF) area and 0.87 +/- 0.047 mumol/l (n = 401) in the high-fluoride (HF) area. No significant rhythm could be found for the diurnal variations in the mean or individual salivary fluoride concentrations. However, in the HF area the individual salivary fluoride concentrations fluctuated widely and randomly.

Influence of increased toothbrushing frequency on dental health in low, optimal, and high fluoride areas in Finland.

In our previous report we found that the dental health of Finnish 13-15-yr-old children had significantly improved from 1973 to 1982. The aim of this study was to assess whether the improved dental health was associated with frequency of toothbrushing and associated use of fluoride dentifrice. In both 1973 and 1982 some 360 children were scored for the DFS index. In each of three towns with 0.2 ppm, 1.0 ppm, and 2.5 ppm fluoride in the drinking water, samples of about 40 children were randomly picked from each age cohort of 13, 14, and 15 yr. The children were grouped into "infrequent", "daily", or "frequent" brushers. Overall, from 1973 to 1982 the proportion of "daily" and "frequent" brushers had increased from 56% to 75% (P less than 0.001). The overall DFST (T = total) and DFSA (A = approximal) scores had declined significantly in all brushing frequency groups. Looking at separate fluoride areas, the actual decline was found to have occurred in the low fluoride area where in 1982 the DFS scores were 50% or less of the 1973 scores (P less than 0.05). In the low fluoride area in 1973, no association was found between brushing frequency and DFS scores whereas in 1982, high brushing frequency was found to be associated with low DFS scores (P less than 0.05). The decrease in DFS scores was suggested at least partly to be associated with the increased frequency of brushing the teeth with fluoride dentifrice.

The Effects of Airborne Fluorides on Oral Conditions in Morocco

The purpose of this study was to determine the prevalence and severity of dental caries and dental fluorosis, as well as various other oral conditions, in 2378 subjects (ages seven to 60) living in the fluoridated area of Khouribga and the non-fluoridated area of Beni Mellal, Morocco. The community index of dental fluorosis (CFI) ranged from 1.99 to 2.80 in the high-fluoride area: Over 90% of the population was affected, and more than one-third of the subjects showed moderate dental fluorosis. However, in Beni Mellal, more than 96% of the dentate subjects examined were free of dental fluorosis, and the CFI of 0.02 was considered not significant. Significant differences were observed between the two areas with respect to caries prevalence. DMFT and DMFS indices were markedly lower in the fluorosis area of Khouribga. The oral conditions of subjects appeared to be better in Khouribga, where the gingival and calculus indices were significantly lower than in Beni Mellal. The analyses of covariance showed no significant differences in plaque accumulation (PI) between the Khouribga and Beni Mellal samples. However, a close statistical correlation was found between PI and GI in Beni Mellal and Khouribga.