Dental Fluorosis Trends in US Oral Health Surveys: 1986 to 2012.

INTRODUCTION: Dental fluorosis has been assessed only 3 times in nationally representative oral health surveys in the United States. The first survey was conducted by the National Institute of Dental Research from 1986 to 1987. Subsequently, the National Health and Nutrition Examination Survey (NHANES) conducted fluorosis assessments from 1999 to 2004 and more recently from 2011 to 2012. A large increase in prevalence and severity of fluorosis occurred between the 1986-1987 and 1999-2004 surveys. OBJECTIVES: To determine whether the trend of increasing fluorosis continued in the 2011-2012 survey. METHODS: We analyzed publicly available data from the 2011-2012 NHANES, calculating fluorosis prevalence and severity using 3 measures: person-level Dean's Index score, total prevalence of those with Dean's Index of very mild degree and greater, and Dean's Community Fluorosis Index. We examined these fluorosis measures by several sociodemographic factors and compared results with the 2 previous surveys. Analyses accounted for the complex design of the surveys to provide nationally representative estimates. RESULTS: Large increases in severity and prevalence were found in the 2011-2012 NHANES as compared with the previous surveys, for all sociodemographic categories. For ages 12 to 15 y-an age range displaying fluorosis most clearly-total prevalence increased from 22% to 41% to 65% in the 1986-1987, 1999-2004, and 2011-2012 surveys, respectively. The rate of combined moderate and severe degrees increased the most, from 1.2% to 3.7% to 30.4%. The Community Fluorosis Index increased from 0.44 to 0.67 to 1.47. No clear differences were found in fluorosis rates among categories for most of the sociodemographic variables in the 2011-2012 survey. CONCLUSION: Large increases in fluorosis prevalence and severity occurred. We considered several possible spurious explanations for these increases but largely ruled them out based on counterevidence. We suggest several possible real explanations for the increases. KNOWLEDGE TRANSFER STATEMENT: The results of this study greatly increase the evidence base indicating that objectionable dental fluorosis has increased in the United States. Dental fluorosis is an undesirable side effect of too much fluoride ingestion during the early years of life. Policy makers and professionals can use the presented evidence to weigh the risks and benefits of water fluoridation and early exposure to fluoridated toothpaste.

Effect of 10% and 15% carbamide peroxide on fracture toughness of human dentin in situ.

PURPOSE: Although damage to the structural integrity of the tooth is not usually considered a significant problem associated with tooth bleaching, there have been some reported negative effects of bleaching on dental hard tissues in vitro. More studies are needed to determine whether the observed in vitro effects have practical clinical implications regarding tooth structural durability. OBJECTIVES: This in situ study evaluated the effect of 10% and 15% carbamide peroxide (CP) dental bleach, applied using conventional whitening trays by participants at home, on the fracture toughness of dentin. METHODS: Ninety-one adult volunteers were recruited (n ≈ 30/group). Compact fracture toughness specimens (approximately 4.5 × 4.6 × 1.7 mm) were prepared from the coronal dentin of recently extracted human molars and gamma-radiated. One specimen was fitted into a prepared slot, adjacent to a maxillary premolar, within a custom-made bleaching tray that was made for each adult participant. The participants were instructed to wear the tray containing the dentin specimen with placebo, 10% CP, or 15% CP treatment gel overnight for 14 nights and to store it in artificial saliva when not in use. Pre-bleach and post-bleach tooth color and tooth sensitivity were also evaluated using ranked shade tab values and visual analogue scales (VASs), respectively. Within 24-48 hours after the last bleach session, the dentin specimens were tested for fracture toughness using tensile loading at 10 mm/min. Analysis of variance, Kruskal-Wallis, χ (2) , Tukey's, and Mann-Whitney U tests were used for statistical analysis. The level of significance was set at p<0.05 for all tests, except for the Mann-Whitney U tests, which used a Bonferroni correction for post hoc analyses of the nonparametric data (p<0.017). Results : The placebo, 10% CP, and 15% CP groups contained 30, 31, and 30 participants, respectively. Mean fracture toughness (+ standard deviation) for the placebo, 10% CP, and 15% CP groups were 2.3 ± 0.9, 2.2 ± 0.7, and 2.0 ± 0.5 MPa*m(1/2) respectively. There were no significant differences in mean fracture toughness results among the groups (p=0.241). The tooth sensitivity VAS scores indicated a significantly greater incidence (p=0.000) and degree of tooth sensitivity (p=0.049 for VAS change and p=0.003 for max VAS) in the bleach groups than in the placebo group. The color change results showed generally greater color change in the bleach groups than in the placebo group (p=0.008 for shade guide determination and p=0.000 for colorimeter determination). CONCLUSIONS: There were no significant differences in in situ dentin fracture toughness results among the groups. The results of this study provide some reassurance that dentin is not overtly weakened by the bleaching protocol used in this study. However, the lack of a statistically significant difference cannot be used to state that there is no effect of bleach on dentin fracture toughness.

The long-term effects of water fluoridation on the human skeleton.

Municipal water fluoridation has notably reduced the incidence of dental caries and is widely considered a public health success. However, ingested fluoride is sequestered into bone, as well as teeth, and data on the long-term effect of exposure to these very low doses of fluoride remain inconclusive. Epidemiological studies suggest that effects of fluoride on bone are minimal. We hypothesized that the direct measurement of bone tissue from individuals residing in municipalities with and without fluoridated water would reveal a relationship between fluoride content and structural or mechanical properties of bone. However, consonant with the epidemiological data, only a weak relationship among fluoride exposure, accumulated fluoride, and the physical characteristics of bone was observed. Analysis of our data suggests that the variability in heterogenous urban populations may be too high for the effects, if any, of low-level fluoride administration on skeletal tissue to be discerned.

How does fluoride affect dentin microhardness and mineralization?

Fluoride (F) has been a useful instrument in caries prevention. However, only limited data exist on the effect of its long-term use on dentin mineralization patterns and microhardness. The objective of this study was to evaluate the influence of tooth F concentration ([F]) and dental fluorosis (DF) severity on dentin microhardness and mineralization. We collected 137 teeth in Montreal and Toronto, Canada, and Fortaleza, Brazil, where optimum or suboptimum levels of water F were 0.2 ppm, 1 ppm, and 0.7 ppm, respectively. Teeth were analyzed for DF severity, dentin [F], enamel [F], dentin microhardness, and dentin mineralization. Dentin [F] correlated with DF severity; enamel [F] correlated with dentin microhardness and dentin mineralization; DF severity correlated with dentin microhardness. Genetic factors (e.g., DF severity) and environmental factors (e.g., tooth [F]) influenced the mechanical properties (microhardness) of the teeth, while only the environmental factors influenced their material properties (e.g., mineralization). Fortaleza teeth were harder and less mineralized and presented higher dentin [F] values. Montreal teeth presented lower levels of DF when compared with both Toronto and Fortaleza teeth.

Is fluoride concentration in dentin and enamel a good indicator of dental fluorosis?

Despite some studies correlating dental fluorosis (DF) and fluoride (F) concentration in dental enamel, no information is available about DF and dentin F concentration. Our objective was to determine the correlation between teeth F concentration and DF severity in unerupted human 3rd molars, and the correlation between dentin and enamel F concentrations in the same tooth. Ninety-nine 3rd molars were studied-53 from Fortaleza, Brazil (F water, 0.7 ppm), 22 from Toronto (1.0 ppm), and 24 from Montreal (0.2 ppm). DF severity was evaluated according to the Thylstrup-Fejerskov Index, while F concentration was analyzed by Instrumental Neutron Activation Analysis. DF severity varied between TF0 and TF4, while F concentration ranged between 39 and 550 ppm in enamel and 101 and 860 ppm in dentin. Our results showed correlation between dentin F concentration and DF (r(S) = 0.316, p = 0.001), but no correlation between enamel F concentration and DF (r(S) = 0.154, p = 0.133). No correlation was observed between dentin and enamel F concentrations in the same tooth (r(S) = 0.064, p = 0.536).

Breastfeeding is protective against dental fluorosis in a nonfluoridated rural area of Ontario, Canada.

To determine the relationship between early infant feeding and dental fluorosis in a non-fluoridated area, 1367 children were examined for fluorosis and given a water sample vial and questionnaire. 752 families responded (55%). Breastfeeding was reported by 69% of respondents, with 53.6% breastfed < 6 months, 35.3% 6-12 months, and 11.1% > 1 year. Formula feeding was reported by 84% of respondents, with 60.3% and 39.7% formula fed for < 1 year and > 1 year, respectively. Fluorosis prevalence was 23.3% and was present in 27.2%, 19.6% and 13.8% of children breastfed for < 6 months, 6-12 months, and > 12 months, respectively (P < .05). About 87% of formula fed children had tap water added to the bottle. Breastfeeding for > 6 months may protect children from developing fluorosis in the permanent incisors. This study suggests that dental professionals should support efforts to increase the rate and duration of breastfeeding.

How does fluoride concentration in the tooth affect apatite crystal size?

Despite fluoride's (F) well-documented ability to prevent caries, the effects of F concentrations on enamel and dentin apatite crystals are unknown. The present study examined the hypothesis that tooth F concentration and tooth crystallite size correlate. One hundred human unerupted third molars were studied-53 from Fortaleza-Brazil (F water 0.7 ppm), 23 from Toronto (1.0 ppm), and 24 from Montreal (0.2 ppm). F concentration was analyzed by Neutron Activation Analysis and apatite crystal size by powder x-ray diffraction. A positive correlation between dentin F concentration and enamel crystallite length and width was found. Enamel crystallite length was significantly greater in teeth from Fortaleza than in teeth from Toronto (p = 0.011) and Montreal (p = 0.003). Enamel crystallite widths were significantly greater in Fortaleza teeth compared with those from Toronto (p = 0.020) and Montreal (p < 0.001). No difference in the dentin crystallite size was seen in the 3 regions. Thus, tooth F concentration and crystallite size correlate.

Fluorosis risk in grade 2 students residing in a rural area with widely varying natural fluoride.

OBJECTIVES: This pilot study was performed to determine the prevalence of dental fluorosis and the association between fluorosis and a number of risk factors in a group of second grade students in a rural, non-fluoridated area of Ontario, Canada. METHODS: Of 1739 students screened during routine health surveillance, 1367 had erupted maxillary central incisors. Fluorosis was scored on these children using the Tooth Surface Index of Fluorosis (TSIF). A fluoride exposure questionnaire and water sample vial was sent home from school with each child. RESULTS: Valid responses were obtained for 752 children (55%). The prevalence of fluorosis in respondents was 23.3%, with 4.9% scoring TSIF of 2 or more. In bivariate analysis, several variables were significantly associated with the prevalence and/or severity of fluorosis. These included: water fluoride concentration, breast-feeding duration, professionally applied topical fluoride, fluoride supplement use, bottle-feeding, fluoridated mouthwash use, and early parental toothbrushing with toothpaste. In logistic regression analysis limited to children living at the current residence for 4 years or more, only four variables had significant independent effects. These were water fluoride concentration, breast-feeding duration, fluoride supplement use, and fluoridated mouthwash use. CONCLUSIONS: These findings indicate that fluorosis is an important concern in non-fluoridated areas. Fluoride supplements should not be recommended unless an independent home water test is performed. Breast-feeding for 6 months or more may protect children from developing dental fluorosis in the permanent incisors.

A re-examination of the pre-eruptive and post-eruptive mechanism of the anti-caries effects of fluoride: is there any anti-caries benefit from swallowing fluoride?

The belief that fluoridated water reduces caries incidence by half stems from years of fluoridation studies where the caries rates of people in various fluoridated and non-fluoridated communities were compared. By their nature, the water fluoridation trials were not able to distinguish between the topical effects of the fluoride in the water and the systemic effects of the fluoride that is inevitably swallowed and incorporated into developing teeth. Some attempts have been made to estimate the contribution of systemic fluoride to the control of dental caries but researchers are discovering that the topical effects of fluoride are likely to mask any benefits that ingesting fluoride might have. In this updated review of the pre-eruptive vs. post-eruptive benefits of fluoride in the prevention of dental caries, a re-examination of the literature, which is often cited to support the notion that swallowing fluoride, either in water or in pill form, was done in recognition of the mounting evidence for the topical mechanism as being the primary mechanism for the prevention of dental caries. Maximum benefits from exposing newly erupted teeth to topical fluoride in the oral cavity may have been seriously under-estimated. This has obvious implications for the use of systemic fluorides to prevent dental caries and forces everyone working in the field to examine more closely the risks and benefits of fluoride in all its delivery forms.

Implications of oral infections on systemic diseases in the institutionalized elderly with a special focus on pneumonia.

Systemic infection in the elderly patient living in a chronic care setting presents a significant burden to the health care system. The extent to which oral organisms cause systemic infections through hematogenous dissemination in the institutionalized elderly is still unknown. A more likely and common route of systemic infection by oral microorganisms is through aspiration of oropharyngeal fluids containing oral pathogenic microorganisms, which colonize the lower respiratory tract and cause pneumonia. Respiratory pathogens emerge in the dental plaque of elderly patients with very poor oral hygiene and severe periodontal disease. In the chronic care setting, aspiration of oropharyngeal fluids contaminated with these bacteria occurs in patients with diminished host defenses, resulting in bacterial pneumonia. This is also a problem in intensive care units in the hospital setting. In one study, pre-rinsing with a 0.12% chlorhexidine gluconate mouthwash significantly lowered the mortality rate from postsurgical pneumonia in patients undergoing open heart surgery. Selective digestive decontamination, a technique involving the topical application of antimicrobials to reduce the risk of colonization of the respiratory tract, has been used to reduce the incidence of nosocomial pneumonia in the acute care setting of hospitals. This technique has not been employed in the nursing home setting. Whether improving oral hygiene would also lower the risk in either of these settings has not been studied. A number of obstacles must be overcome in designing studies to investigate the relationship between oral infections and lung infections in the institutionalized elderly. Ethical issues must be addressed, and full collaboration of the medical team is required. Future studies should establish whether reducing the risk for pneumonia in the institutionalized elderly is possible through improved oral health.

Oral health and history of respiratory tract infection in frail institutionalised elders.

OBJECTIVES: The purpose of this study was to look for a relationship between history of respiratory tract infection (RTI) and oral health in very old subjects. SETTING AND SUBJECTS: 302 frail elders (mean age: 85 years) living in a medical care facility were examined by one dentist. OUTCOME MEASURES: The incidence of RTI over 1 year had been recorded along with markers of nutritional status and degree of dependency. The oral examination comprised an evaluation of hygiene, quality of prostheses and the prevalence of caries, periodontal disease and mucosal disorders. RESULTS: One third (33%) of the subjects had experienced at least one episode of RTI, and a fifth (19%) had visited the dentist in emergency. The incidence of RTI had been greater among dentate subjects and those who came to the dentist in emergency. The dentate subjects with a history of RTI had higher plaque score (P = 0.02). Half (49%) of the subjects had oral disorders that could develop in a dental emergency and these subjects had had a higher risk of RTI (relative risk: 1.9, 95% confidence interval: 1.1-3.9). The presence of selected oral disorders associated with low serum albumin increased the relative risk of having had RTI to 3.2 (1.5-6.7). The association between presence of actual oral health problems and previous experience of RTI was more noticeable in those who had poor general health or were more debilitated. CONCLUSIONS: The present study suggests that poor oral hygiene and the presence of potential emergency could be major risk factors for RTI among the frail elderly.

Comparison of recommended and actual mean intakes of fluoride by Canadians.

The findings of two separate 1993 reports, one of the actual intake of fluoride by Canadians and the other on their recommended fluoride intake, are summarized and compared. Recent increases in very mild and mild dental fluorosis suggest that the gap between current fluoride intake and recommended intake is narrowing. The daily swallowing of fluoride dentifrice makes a large contribution to the actual total daily fluoride intake, especially in children seven months to four years of age, the age group most susceptible to fluorosis in the anterior permanent teeth. Because of the available data and methods used in each study, the reported actual and recommended fluoride intakes vary greatly both within and between age groups. It is likely that individual variation in fluoride intake also varies greatly. Comparison of the data in the two reports revealed that, for breast-fed infants and nearly all other age groups without fluoridated water, the ranges of the estimates of actual intake are lower than the recommended ranges. However, for formula-fed infants and all other age groups using fluoridated water, the estimates of actual intake greatly exceed the recommended intake, especially for the seven months to four years age group. Ingestion of fluoride at these levels during tooth development will contribute to dental fluorosis. All of the age groups have fluoride intake estimates below levels at which skeletal signs of fluoride exposure are noticed. Nevertheless, exposure to fluoride should be closely monitored and inappropriate use of discretionary fluorides curtailed.

Treating dental caries as an infectious disease. Applying the medical model in practice to prevent dental caries.

The above diagnostic and treatment principles may be self evident to most dental practitioners. To many, however, this treatment philosophy is a new one. Continuing dental education and quality assurance programs will play a significant role in helping dentists make the philosophical shift from a highly technical restorative approach to one that uses the medical model and treats dental caries as an infectious disease. While a total cure in humans suffering from dental disease may never be attainable, dental practitioners should soon be better able to direct more of their attention to the patients who already demonstrate a high incidence of dental decay and to those who are clearly at risk to develop future dental decay.