High prevalence of dental fluorosis among schoolchildren in three villages in Vavuniya District: an observational study

Background: Studies of groundwater sources in Sri Lanka show that in the entire Northern, North Central, Uva and Eastern Provinces, and also in a large area of the North Western Province, groundwater fluoride content is within the range 1.0 mg/l and 3.0 mg/l. The WHO recommended safe upper limit of fluoride for drinking water is 1.5 mg/l. Objective: Our objective was to determine the prevalence and degree of dental fluorosis in a cohort of schoolchildren in Sinnasippikulam in Vavuniya District, the fluoride content in their serum and urine, and fluoride levels in drinking water in dug wells of the area. Methods: Invitations in Tamil and Sinhala were sent to all households by courier. Demographic information and oral hygiene practices of 307 responsive children were recorded by interviewing children and their mothers. Detailed clinical examinations were performed according to WHO basic methods, with some modifications. Assessment of dental fluorosis in the children was done according to Dean's Index codes and criteria. Results: We found drinking water sources (dug wells) in Sinnasippikulam (n= 82) to have a high mean concentration of fluoride ( x̄ 1.58+ 0.69 mg/l). Of 307 children examined, 224 (72.9%) had clinical evidence of dental fluorosis of varying degrees of severity. The mean fluoride level in serum of schoolchildren was 0.198 mg/l (SD + 0.074; S.E.M. 0.013), and in their urine, 1.44 mg/l (SD + 0.59; SEM 0.11). Conclusions: Our results show that harmful levels of fluoride are extremely common in groundwater sources in the study area, and consequently, dental fluorosis is highly endemic (72.9%) among resident schoolchildren.

Remembering Juan Navia.

Juan Navia died on September 4, 2010. Those who knew him as the director of the University of Alabama's John J. Sparkman Center for International Public Health Education and later the dean of UAB School of Public Health watched him train and shape the next generation of global public health leaders with a kind heart and a firm, but gentle, hand. On this third anniversary of Professor Navia's passing, in response to an invitation from the Journal of Dental Research to write an essay on an educator who influenced the professional trajectories of many people, we have put together an account of some of his contributions and attributes to highlight this remarkable leader's accomplishments in and impact on dental public health and global nutrition.

Are procedures performed by dental auxiliaries safe and of comparable quality? A systematic review.

The objective of the current study was to systematically evaluate the existing evidence in relation to the safety, quality, productivity or cost-benefit, and patient satisfaction of the procedures performed by the different groups of dental providers. Due to the diversity of the procedures performed and the outcomes measured, it was not possible to create pooled estimates in a meaningful manner. Therefore, summary results of individual studies are presented and critically evaluated.

Is workplace screening for potentially malignant oral disorders feasible in India?

BACKGROUND: Because of delays in diagnosis, oral cancer usually presents for therapy at a late stage. Patients are unaware of having lesions as they are mostly asymptomatic and physicians generally do not examine the mouth sufficiently. People in rural areas or are underserved may not frequently visit the dentist who can easily pick up these lesions early. Screening programs are useful in that regard. Such programs in general are conducted by either inviting people to come to a screening center or by health care workers visiting the individual households. However, those who work during the day may not visit screening centers or be at home during the day of the screening by a visiting health care worker. Workplace screening overcomes these challenges. METHODS: To assess the feasibility of a screening program to detect potentially pre-malignant oral disorders in a workplace in India, clinically visible mucosal lesions were compared with the clinical photographs of the same lesions assessed by an expert. Role of smoking, alcohol, and chewing betel quid and tobacco in the etiology of those lesions were assessed. RESULTS: Sixty-nine percent of the eligible subjects participated in the screening (n=1613). Prevalence of leukoplakia was 5%. Bidi (OR=35.6), and cigarette smoking (OR=22.8), alcohol (OR=17.6), and tobacco and areca nut chewing (OR=7.5), were significantly associated with leukoplakia and erythroplakia (all P< 0.05). CONCLUSIONS: Conduction of a screening program by valid visual inspection to detect potentially malignant oral disorders within a workplace is not only feasible but also effective.

Periodontal pathogens and gestational diabetes mellitus.

In previous cross-sectional or case-control studies, clinical periodontal disease has been associated with gestational diabetes mellitus. To test the hypothesis that, in comparison with women who do not develop gestational diabetes mellitus, those who do develop it will have had a greater exposure to clinical and other periodontal parameters, we measured clinical, bacteriological (in plaque and cervico-vaginal samples), immunological, and inflammatory mediator parameters 7 weeks before the diagnosis of gestational diabetes mellitus in 265 predominantly Hispanic (83%) women in New York. Twenty-two cases of gestational diabetes mellitus emerged from the cohort (8.3%). When the cases were compared with healthy control individuals, higher pre-pregnancy body mass index (p=0.004), vaginal levels of Tannerella forsythia (p=0.01), serum C-reactive protein (p=0.01), and prior gestational diabetes mellitus (p=0.006) emerged as risk factors, even though the clinical periodontal disease failed to reach statistical significance (50% in those with gestational diabetes mellitus vs. 37.3% in the healthy group; p=0.38).

Immune response in humans to a nasal boost with Streptococcus mutans antigens.

We previously reported that a Streptococcus mutans enriched-glucosytransferase (E-GTF) preparation induces an immune response following intranasal, but not tonsillar, immunization of humans. In this study, we determined whether intranasal immunization of these subjects 2 years later resulted in augmented immune responses compared to those seen in control subjects. Subjects previously immunized via the intranasal (IN, n = 7) or tonsillar (IT, n = 7) route and control (n = 12) subjects were immunized via the intranasal route with E-GTF. Nasal wash, saliva, and serum were collected before immunization and then weekly for 3 months after immunization. Significant (P < 0.05) mucosal and serum immunoglobulin A (IgA) anti-E-GTF responses were observed in all three groups. Nasal and serum IgA anti-E-GTF responses were significantly higher (P < 0.05) in the IN group. The salivary responses in the three groups were, in general, similar. These results indicate that intranasal immunization primes the immune system for a localized secondary response to S. mutans antigens.

Fracture of ProFile nickel-titanium rotary instruments: a laboratory simulation assessment.

AIM: To determine the incidence of ProFile nickel-titanium rotary instrument fracture in an endodontic laboratory simulation. METHODOLOGY: Three hundred and sixty dental students used 2880 ProFile nickel-titanium rotary instruments to prepare 1440 simulated root canals in 720 plastic teeth, and another 2880 ProFile nickel-titanium rotary instruments to prepare 1440 natural root canals in 720 extracted teeth. A standardized crown-down rotary instrumentation technique was used, which included measures to prevent fracture. Rotary instrument fracture was monitored during and after completion of the laboratory simulation exercises to determine the incidence of fracture. When fracture occurred, data were collected concerning the size of the instrument, the length of the instrument fragment, the location of the fragment in the canal and the curvature of the canal in which the instrument fractured. RESULTS: The incidence of instrument fracture was 0.41% in plastic simulated canals and 0.31% in natural root canals. The overall incidence of instrument fracture was 0.36%. Of the instruments that fractured 67% were size 25, 0.04 taper; and 81% of the fragments were located in the apical third of the canal. The mean, median and mode of the fragment lengths were all 3 mm. CONCLUSIONS: The low overall incidence of fracture in this study suggests that ProFile rotary instruments are safe for use by dental students in laboratory simulations and that if preventive measures are taken the incidence of instrument fracture can be minimized.

Mode of delivery and other maternal factors influence the acquisition of Streptococcus mutans in infants.

S. mutans plays a key role in dental caries. The extent to which perinatal events influence the acquisition of S. mutans is unclear. We hypothesized that several maternal factors, including the mode of delivery, influence the initial acquisition of S. mutans in infants. A prospective cohort study was conducted in 156 mother-infant pairs. The study found that maternal gestational age (p = 0.04), S. mutans level (p = 0.02), caries score (p = 0.02), sexually transmitted disease (STD) infection experience (p = 0.01), and family income (p = 0.03) had significant effects on the acquisition of S. mutans. Among infants who became infected, those delivered by Caesarean section acquired S. mutans 11.7 mos earlier than did vaginally delivered infants (p = 0.038). C-section infants harbored a single genotype of S. mutans that was identical to that of their mothers (100% fidelity). Analysis of the data demonstrated the possible perinatal influences on infants' acquisition of a member of the cariogenic microbiota, and its potential effect on caries outcome.

Periodontal disease and prematurity among non-smoking Sri Lankan women.

The hypothesis that periodontal disease is associated with pre-term low birthweight was tested in a prospective follow-up study of rural prima-gravida women (N = 227) who were free of tobacco, alcohol, and drug use. Women with 3rd trimester mean probing pocket depths, plaque, and bleeding scores that were greater than the median value in the cohort were defined as "exposed". There were 17 (7.5%) preterm low birthweight singleton deliveries in the cohort (among "exposed" = 12%; among "unexposed" = 5.6%; Odds Ratio = 2.3; 95% CI = 0.9-6.3). After adjustment for the independent variables, the OR for preterm low birthweight in relation to "exposure" was 1.9 (95% CI = 0.7-5.4). Our results are only suggestive of an association between periodontal disease and preterm low birthweight, perhaps indicating that previously reported associations may have been subjected to residual confounding due to tobacco, alcohol, and drug use.

Intranasal immunization of humans with Streptococcus mutans antigens.

To evaluate the effectiveness of a low dose of soluble or liposomal (L) glucosyltransferase-enriched preparation (E-GTF) in inducing mucosal immune responses after intranasal immunization, 12 adults were immunized on days 0 and 7 by the IN route with 62.5 microg of soluble E-GTF or L-E-GTF. An increase in the mean salivary IgA anti-E-GTF response (P < 0.03) was seen in the L-E-GTF but not the soluble E-GTF group. A significant increase (P < 0.05) in the mean specific IgA antibody activity was also seen in nasal wash from both groups. Although the nasal wash responses were higher in the L-E-GTF than in the soluble E-GTF group, they were not significantly different. The soluble E-GTF immunized group showed a higher serum IgG response than the L-E-GTF immunized group on day 90 (P < 0.05). These results indicate that as little as 62.5 microg of E-GTF, when given by the intranasal route, induced an IgA response in secretions.

Effect of age on immunoglobulin A subclass distribution in human parotid saliva.

Two subclasses of immunoglobulin A (IgA) antibodies are produced in humans, IgA1 and IgA2, IgA2 being more resistant to digestion by bacterial proteases than IgA1. The amount of IgA in saliva has been shown to vary with age; however, little is known about the correlation between IgA subclass distribution in saliva and age. The purpose of this study was to determine whether differences exist in the levels and ratio of IgA subclasses in parotid saliva of children and adults. Parotid saliva was obtained from healthy children (age range 6-12 years, n = 14) and adults (age range 22-51 years, n = 20) using Schaefer cups. Samples were analyzed for levels of total IgA, IgA1, and IgA2 by ELISA. IgA and IgA1 levels were significantly higher in adults than in children. However, no differences were seen in the ratio of IgA1 and IgA2 in the two groups of subjects. These findings indicate that levels of IgA increase with age, whereas the IgA subclass ratio is established early in life.

Lack of effect of chlorhexidine varnish on Streptococcus mutans transmission and caries in mothers and children.

In a randomized clinical trial, we evaluated the effect of a 10% chlorhexidine varnish (Chlorzoin) on the mother-child transmission of Streptococcus mutans and on subsequent caries experience. Chlorhexidine (n = 38) or a placebo varnish (n = 37) was applied to the dentitions of 75 mothers at a time when their first babies were about 6 months old (approximate time of first tooth emergence). Three more applications at weekly intervals and subsequent applications at 6-month intervals followed the initial application. The mother-child pairs were followed up until the child's fourth birthday. Maternal salivary S. mutans levels in the treatment group remained significantly lower (p < 0.05) compared to the control group up to 12 months after the initial application. However, this intervention did not significantly alter the S. mutans colonization in children or the caries increment in either the mother or the child.

Humans immunized with Streptococcus mutans antigens by mucosal routes.

Strategies aimed at the prevention of Streptococcus mutans infection and dental caries include mucosal immunization, which results in salivary anti-S. mutans responses. The purpose of this study was to evaluate the effectiveness of nasal vs. tonsillar immunization with S. mutans antigens in inducing salivary immune responses. Twenty-one adult subjects were immunized twice, within a seven-day interval, with a glucosyltransferase-enriched preparation (E-GTF) administered by nasal or tonsillar topical spray. Parotid saliva, nasal wash, and serum were collected prior to and at one- to two-week intervals for 3 months following immunization and were assayed by ELISA for anti-E-GTF activity. Results were analyzed by means of the mixed-models procedure with p < 0.05 level of significance. Significantly higher anti-E-GTF responses were detected in saliva and nasal wash samples from the group immunized by the nasal compared with the tonsillar route, indicating that nasal immunization was more effective in inducing mucosal responses in adults.

Utilization of dental sealants by Alabama Medicaid children: barriers in meeting the year 2010 objectives.

PURPOSE: As a national objective, 50% of US children are expected to have dental sealants on at least one permanent molar by the age of 14 years. The present study was conducted to estimate the prevalence of dental sealants among Alabama Medicaid children and to evaluate the characteristics of the sealant users and non-users so the potential barriers in meeting the year 2000/2010 sealant objectives can be identified. METHODS: Alabama Medicaid 1990-1997 claims for children (N = 3,683,842) were analyzed using basic descriptive statistics, likelihood ratio, Chi-Square and t-tests, and ANOVA. Logistic regression analysis was used in identifying the predictors of dental sealant utilization. RESULTS: Nearly 22 percent of children had at least one sealant claim by 12 to 14 years of age (white = 28.3%; Black = 19.8%; OR = 1.6, 95% CI = 1.4-1.8; female = 23.6%; male = 19.7%; OR = 1.3, 95% CI = 1.1-1.4). 5- to 9-year-olds were more likely to have sealants compared to 11- to 14-year-olds (OR = 4.1, 95% CI = 2.7-6.1). The availability of a Medicaid accepting dentist within the county of residence was a significant predictor (OR = 1.5, 95% CI = 1.1-2.2). Less than 2% of the annual amount claimed for total dental services in Alabama was related to sealants and the providers were reimbursed only for 50% to 70% of the amount claimed for sealant procedures. CONCLUSIONS: Racial and gender disparities in obtaining care, non-availability of a Medicaid-participating dentist within the county, and lower payment/claim ratio may make the national sealant objective difficult to achieve in Alabama.

The antimicrobial approach to caries management.

Dental caries is an infectious disease of bacterial origin. The use of antimicrobial agents to reduce or eliminate the bacteria associated with caries follows the approach used to combat other infectious diseases of humans. Unfortunately, only a few dozen studies have sufficient resolving power to make inferences as to the anticaries efficacy of the antimicrobial approach to caries management. Here, we comment on the findings of the RTI/UNC review concerning antimicrobials, discuss additional findings not covered in that review, and make recommendations based upon both the available literature and from our own experience. Even though the studies published thus far are inconclusive or lack sufficient demonstration of efficacy to recommend a specific approach involving antimicrobial agents in routine clinical practice, several pieces of information from these studies suggest future avenues of investigation.

The association between Porphyromonas gingivalis-specific maternal serum IgG and low birth weight.

BACKGROUND: In Alabama, low birth weight (LBW) infants are about 20 times more likely to die before their first birthday compared to normal birth weight infants. While the rate of LBW has been consistently higher among African Americans compared to whites, there has been a gradual increase in LBW for both African Americans and whites over the last 15 years. In an attempt to identify modifiable risk factors for LBW, we have previously reported that a pregnant woman's poor periodontal health may be an independent risk factor for low birth weight. METHODS: A predominantly African American and socioeconomically homogeneous group of 448 women was followed from the second trimester of their first pregnancy. Thirty-nine LBW cases were observed at the end of follow-up. Using 17 preterm LBW cases and 63 randomly selected controls from the above cohort, the periodontal pathogen-specific maternal serum IgG levels during the second trimester of pregnancy were evaluated in relation to birth weight of the infant, while controlling for known risk factors for LBW. RESULTS: Porphyromonas gingivalis (P.g.)-specific maternal serum IgG levels were higher in the LBW group (mean 58.05, SE = 20.00 microg/ml) compared to the normal birth weight (NBW) group (mean 13.45, SE = 3.92 microg/ml; P= 0.004). Women with higher levels of P.g.-specific IgG had higher odds of giving birth to LBW infants (odds ratio [OR] = 4.1; 95% confidence interval [CI] for odds ratio = 1.3 to 12.8). This association remained significant after controlling for smoking, age, IgG levels against other selected periodontal pathogens, and race. CONCLUSIONS: Low birth weight deliveries were associated with a higher maternal serum antibody level against P. gingivalis at mid-trimester.

Early expression of iepsilon, CD23 (FcepsilonRII), IL-4Ralpha, and IgE in the human fetus.

BACKGROUND: A major predictor of childhood atopy is the concentration of IgE in the cord blood, but whether the source of cord blood IgE is maternal or fetal remains unclear. OBJECTIVE: We sought to determine the pattern of in situ IgE production during ontogeny. METHODS: Ninety-seven fetal, 142 natal, and 96 childhood samples were analyzed by using reverse transcription PCR for transcription of VDJCepsilon, Iepsilon, and CD23. Thirty-eight fetal liver samples were analyzed for the IL4RA genotype. RESULTS: IL-4Ralpha, CD23a, CD23b, and sterile Iepsilon transcripts were present as early as 8 weeks' gestation. VDJCepsilon transcripts were found in second-trimester fetal liver and third-trimester cord blood, although they were rare. VDJCepsilon transcripts were more common in the blood of children 9 months and older. Sequence analysis suggested that fetal VDJCepsilon was the product of selection. All fetal livers actively transcribing Iepsilon, VDJCepsilon, and IL-4Ralpha contained at least one copy of the atopy-associated IL4RA*A1902G polymorphism. CONCLUSION: The human fetus contains B cells that are primed to undergo IgE class switching from the earliest stages of ontogeny and can produce endogenous IgE by 20 weeks' gestation. However, IgE-producing cells are rare until 9 months after birth.

Natural history of Streptococcus sanguinis in the oral cavity of infants: evidence for a discrete window of infectivity.

The heterogeneous group of oral bacteria within the sanguinis (sanguis) streptococci comprise members of the indigenous biota of the human oral cavity. While the association of Streptococcus sanguinis with bacterial endocarditis is well described in the literature, S. sanguinis is thought to play a benign, if not a beneficial, role in the oral cavity. Little is known, however, about the natural history of S. sanguinis and its specific relationship with other oral bacteria. As part of a longitudinal study concerning the transmission and acquisition of oral bacteria within mother-infant pairs, we examined the initial acquisition of S. sanguinis and described its colonization relative to tooth emergence and its proportions in plaque and saliva as a function of other biological events, including subsequent colonization with mutans streptococci. A second cohort of infants was recruited to define the taxonomic affiliation of S. sanguinis. We found that the colonization of the S. sanguinis occurs during a discrete "window of infectivity" at a median age of 9 months in the infants. Its colonization is tooth dependent and correlated to the time of tooth emergence; its proportions in saliva increase as new teeth emerge. In addition, early colonization of S. sanguinis and its elevated levels in the oral cavity were correlated to a significant delay in the colonization of mutans streptococci. Underpinning this apparent antagonism between S. sanguinis and mutans streptococci is the observation that after mutans streptococci colonize the infant, the levels of S. sanguinis decrease. Children who do not harbor detectable levels of mutans streptococci have significantly higher levels of S. sanguinis in their saliva than do children colonized with mutans streptococci. Collectively, these findings suggest that the colonization of S. sanguinis may influence the subsequent colonization of mutans streptococci, and this in turn may suggest several ecological approaches toward controlling dental caries.

Associations of MHC genes with levels of caries-inducing organisms and caries severity in African-American women.

The aim of this investigation was to evaluate the relationship between MHC alleles at the HLA-DRB1, DQB1 and TNFa microsatellite loci and levels of oral bacteria that play a role in the etiology of dental caries, and the DMFS index in 186 AA primparous women. The average age of the cohort was 20.8+/-3.7 years. The median DMFS index was 9 (range 0-68). High levels of S. mutans were positively associated with DRB1*3 and DRB1*4 presence (p < or = 0.005). DRB1*8 was positively associated with higher levels of S. mutans as a percentage of total Streptococci (p = 0.04). DRB1*1 was positively associated with high levels L. casei (p = 0.04). DQB1 alleles were not observed associated with oral bacterial levels. TNFa allele 103 was negatively associated (p = 0.04), and TNFa 117 was positively associated (p = 0.007), with high levels of L. acidophilus. No significant associations were observed between any DRB1, DQB1 or TNFa allele and the DMFS index. These results support an hypothesis of an association between host HLA class II and TNFa genetic profile and colonization of S. mutans, L. casei, and L. acidophilus thought to be pathogens involved in the etiology of dental caries.

IgM heavy chain complementarity-determining region 3 diversity is constrained by genetic and somatic mechanisms until two months after birth.

Due to the greater range of lengths available to the third complementarity determining region of the heavy chain (HCDR3), the Ab repertoire of normal adults includes larger Ag binding site structures than those seen in first and second trimester fetal tissues. Transition to a steady state range of HCDR3 lengths is not complete until the infant reaches 2 mo of age. Fetal constraints on length begin with a genetic predilection for use of short DH (D7-27 or DQ52) gene segments and against use of long DH (e.g., D3 or DXP) and JH (JH6) gene segments in both fetal liver and fetal bone marrow. Further control of length is achieved through DH-specific limitations in N addition, with D7-27 DJ joins including extensive N addition and D3-containing DJ joins showing a paucity of N addition. DH-specific constraints on N addition are no longer apparent in adult bone marrow. Superimposed upon these genetic mechanisms to control length is a process of somatic selection that appears to ensure expression of a restricted range of HCDR3 lengths in both fetus and adult. B cells that express Abs of an "inappropriate" length appear to be eliminated when they first display IgM on their cell surface. Control of N addition appears aberrant in X-linked agammaglobulinemia, which may exacerbate the block in B cell development seen in this disease. Restriction of the fetal repertoire appears to be an active process, forcing limits on the diversity, and hence range of Ab specificities, available to the young.