Topical fluorides: a discussion of risks and benefits.

Inadvertent ingestion of fluoride from topical procedures poses the risk of dental fluorosis in age-susceptible users. This risk can be minimized for mouthrinsing by restricting it to those above the age-susceptible limit. Operators administering topical fluoride treatments can take practical precautions that have been shown to reduce the amount of fluoride retained and, thus, reduce ingestion. Clinical and epidemiological studies have failed to establish that dentifrice ingestion by young children constitutes a serious fluorosis risk. Discussion of risk must consider the effect of perceived risks upon the public.

An evaluation of the use of professional (operator-applied) topical fluorides.

Application of fluoride solutions, gels, varnishes, and prophylaxis pastes is reviewed as well as the sequential APF/SnF2 office-rinse method. The most widely-used technique is with 1.23% APF gel (12,300 ppm F) in trays. Clinical results from this method are similar to those achieved with an APF solution of the same fluoride concentration. A professional APF gel/tray application need not be preceded by a prophylaxis, should last four min, and should not be followed by a water rinse for 30 min. Fluoride varnishes are newer topical fluoride agents, but their relative efficacy, compared with other proven caries-inhibitory methods, remains to be fully determined. In general, fluoride prophylaxis pastes have not been shown to inhibit caries; however, their use is justified by the ability of some to replenish fluoride lost from the abrasive action of the paste on tooth enamel. The sequential office-rinse method has not been tested in randomized clinical trials, and its use cannot be recommended.

Ethical and legal considerations associated with clinical field trials.

As members of a hypothetical review board, we have evaluated the protocol of a clinical caries trial following the recommendations proposed by the National Commission. The potential risks to the subjects were described as well as the potential benefits that both the participants and society might derive from the study. A new element of the institutional review process was the determination of the scientific validity of the study. The Commission was cautious in indicating that, while such a review should be conducted, studies of marginal scientific importance might be allowed, as long as the risks were minimal. Clinical studies of cariostatic agents traditionally use children as subjects. The rights of children as research subjects were addressed in detail by the Commission. Its recommendation that "assent" of the children be secured is significant. Nevertheless, the Commission distinguished between consent and assent. Consent of parents must be actively secured while assent of the children is acquired by their passive acquiescence to participation. We have raised questions at a practical level throughout this presentation in order to stimulate discussion. These questions, however, do not have simple answers. In the time remaining, we trust the complex issues involved will be discussed further.

Fluoride deposition in human enamel in vivo from professionally applied fluoride prophylaxis paste.

Deciduous teeth were collected from children who received professional prophylaxis with an acidulated phosphate-fluoride (APF) or placebo paste and were analyzed to determine fluoride uptake. Enamel fluoride level was increased by the APF paste approximately 300 ppm at a depth of 2.5 micrometers during the first month after the prophylaxis was administered, after which it returned to pretreatment levels.

Snack food intake of adolescents and caries development.

The relationship between the frequency of eating various snack foods, socioeconomic variables, and an increment in caries was studied in 143 adolescents. There were negative correlations between DMFT increments and the frequency of apples, fruit juice, and sugarless gum intake, and a positive association of DMFT increments with chocolate candy intake and spending money.

Two years' effect on the primary dentition of mouthrinsing with a 0.2% neutral NaF solution.

The benefits to the primary teeth from a school-based fluoride mouthrinsing program are presented. Children in grades 1--4, residents of a fluoride-deficient community in New York, rinsed an average of 49 times during 2 school years using a 0.2% neutral NaF solution. Rinsing was done under the supervision of homeroom teachers. Differences in caries prevalence of 20.0% (dfs/child) or 23.8% (dfs/100s) were found in children who participated in the rinsing program for 2 years compared with baseline caries scores of children who never rinsed. Surface specific differences in caries prevalence after 2 years were: 27.5% for proximal surfaces, 24.1% for buccolingual surfaces, and 12.4% for occlusal surfaces.

Supervised weekly rinsing with a 0.2% neutral NaF solution: results after 5 years.

The effect on caries prevalence of the permanent dentition was evaluated after 5 years of weekly rinsing (130 scheduled rinses) with a 0.2% neutral NaF solution. The program was conducted in the Three Village Central School District, New York, U.S.A. (F less than or equal to 0.1 part/10(6). First to sixth grade children who rinsed from 1 to 5 years respectively had a caries prevalence reduction of 45.3% (DMFT) and 47.4% (DMFS) compared to baseline scores of children who were examined before the rinsing program began. The highest caries reduction, 81.3%, was found on proximal surfaces. Two variables influenced the cariostatic benefits associated with fluoride rinsing. The younger that children entered the program and the longer that they rinsed, the greater were the accumulated benefits.

Comparisons of caries prevalence of children with different daily toothbrushing frequencies.

Clinical caries examinations, supplemented by bite-wing radiographs, were conducted on 290 schoolchildren. The children ranged from 12 to 15 years of age and were residents of a fluoride-deficient community in New York State. The children were divided into two groups based upon their stated daily toothbrushing frequency, namely, those brushing once or less/day and those brushing twice or more/day. Mean DMFS and DMFT scores were recorded for children in both categories. A trend was noted that more frequent brushing was associated with less caries activity. For females and male-females combined the differences in mean DMFS and DMFT scores between those children brushing once a day or less. The caries scores for males in these two brushing groups were marginally significant (P less than .05). Ninety percent of the children used fluoride-containing dentifrices. The inverse relationship between brushing frequency and caries activity may be related to the more frequent fluoride contact when the children brush.

Teaching occlusal sealant therapy to dental students Department of Children's Dentistry, State University of New York at Stony Brook.

The use of sealants has been taught from its inception by the Department of Children's Dentistry at Stony Brook. The average student, during his two years of clinical experience, applies approximately 50 sealants. Estimating that each sealant takes about 20 minutes to apply (probably a realistic figure considering preparation time, and the fact that the students are inexperienced and usually working without assistants), about 17 hours, or six percent of a student's clinic time in Children's Dentistry, is spent placing sealants. In addition the students have reading assignments and four contact hours of lectures and a clinical class exercise in sealant therapy. We have found that the six and 12-month retention of sealants by our dental students is comparable to that reported by others in which the sealant was applied by dentists or specially trained auxiliaries. This is due, in part, to a policy of having faculty deliberately try to pry off the sealant before the patient is dismissed. (This procedure, we feel, should also be done by the practicing dentist). Our studies have also found that dental students have more success when they use an autopolymerized system and when rubber dam isolation is used while working with a UV-polymerized system. Despite our didactic and clinical class exercise program, our students still commit common errors in sealant placement that requires the vigilance of our faculty to both detect and correct. Although the number of individuals contacted was small, it was gratifying to find that all of our graduates, who were able to, used sealants in their practices.

A critique of topical fluoride methods (dentifrices, mouthrinses, operator-, and self-applied gels) in an era of decreased caries and increased fluorosis prevalence.

Within the last 20 years there has been a decrease in the caries prevalence of US schoolchildren, a change in the intraoral caries pattern, and a slowing of the progress of lesions. Simultaneously, the prevalence of enamel milder, cosmetically acceptable forms and is more noticeable in fluoride-deficient communities than those with optimal or above-optimal water fluoride concentrations. Circumstantial evidence indicates that a principal contributor to the caries decline is the extensive use of fluoride dentifrices. Conversely, although use of a fluoride dentifrice can add to the total daily amount of ingested fluoride in preschool children, there is little evidence to suggest that dentifrice ingestion is a principal factor causing the fluorosis increase. The value of fluoride methods may be assessed in relative or absolute terms. The relative, or percentage, caries reduction attributed to fluoride mouthrinses and gels appears to be a property intrinsic to the methods themselves and generally is little affected by the caries activity of the population being treated. Conversely, the absolute, or numerical, caries reduction is dependent upon the level of disease in the population. Thus, the reported caries decline reduces the number of surfaces prevented from developing caries, even though the percentage reduction remains substantially unchanged. Although inadvertent ingestion of fluoride can result from the use of mouthrinses and gels, there is little evidence to suggest that they have contributed to the fluorosis increase. When using topical methods, prudence should prevail to avoid ingestion of fluoride. Fluoride dentifrices should continue to be used routinely, and although lower potency dentifrices may be considered, the literature does not provide strong support for their need. Use of fluoride mouthrinses and gels for individual patients should be predicted upon their caries activity or risk. Use of these methods in public health programs is a matter of cost-effectiveness, which will be influenced by the caries prevalence of the target population.

Review of the anticaries effectiveness of professionally applied and self-applied topical fluoride gels.

Of the five types of topical fluoride gel products available in the United States, two have not been clinically tested in randomized double blind clinical trials. For those tested, the averaged results of clinical trials involving schoolchildren in fluoride-deficient communities indicate a caries reduction of approximately 26 percent from either a professional or self-administered program. A similar relative reduction can be expected from programs conducted in fluoridated communities, but the absolute caries inhibition is less. Twice-a-year professional applications are more effective than once-a-year applications, and self-applications using trays are more effective than applying the gel on a toothbrush. For subjects beyond school age, there are few clinical studies of either self-applied or professionally applied gels; however, current epidemiological evidence does not indicate a need for public health caries preventive programs for healthy employed adults. For medically compromised patients, especially those exhibiting rampant caries associated with radiation-induced xerostomia, a variety of topical gel procedures appear to be effective in limiting caries.

A half-century of community water fluoridation in the United States: review and commentary.

The nearly 50-year history of community water fluoridation is reviewed with the major emphasis on the benefits and safety of fluoridation. Other aspects of water fluoridation also described include the apparent reduction in measurable fluoridation benefits because of the abundance of other fluoride sources, the diffusion of fluoridation effects into fluoride-deficient communities, preeruptive and posteruptive effects, technical and cost aspects, sociopolitical and legal issues that affect the successful fluoridation of communities, and alternatives to community water fluoridation. The majority of studies have evaluated the effectiveness of water fluoridation on the permanent teeth of children, while there are fewer studies on deciduous teeth and in adults; the relationship between fluoride ingestion and bone health needs further clarification; the sociopolitical issues of fluoridation need to be better understood.

Occlusal sealants: an overview of clinical studies.

Sealant application is a technic in which a rapid transfer of technology occurred from the research community, abetted by industry, to individual practitioners and public health personnel. Less than five years after publication of the results of the first clinical trial, sealant systems were commercially available. Since the first published report of the effectiveness of sealants in inhibiting occlusal caries, many other investigators have substantiated the dramatic caries-inhibiting potential and degree of retention that can be obtained with sealants. Despite the high degree of success and the universality of positive reports, there is a significant lag in the utilization of sealants both by dental practitioners and public health programs. One reason appears to be the perception that sealants are not cost-effective. This is a concept that the dental research community may have unwittingly fostered by conducting cost analyses on a technic that was still in its initial stages of development. It behooves the dental profession, both the public and private sectors, to accord sealants recognition for their proven effectiveness and retentive characteristics. At the same time, the dental profession should suspend judgment on their costs until reports of studies conducted specifically for this purpose appear.

Three-year root caries increments: implications for clinical trials.

Seven hundred and ninety-six adult subjects (mean age, 39.9 years) received visual-tactile examinations for root caries over a three-year period. All subjects were employed or were the spouses of employees and resided in fluoride-deficient communities on Long Island, New York. During the three-year observation period, 81.4 percent of the subjects did not develop root caries. The 18.6 percent who developed root caries averaged 0.8 DFS/year. The subjects' ages and baseline root DFS status were associated with the development of a root DFS increment. The older the patient, especially aged 45 and older, the greater was the risk of developing root lesions or having root fillings placed. Subjects who had a root DFS score at baseline also were more likely to experience a root DFS increment. It is recommended that when designing clinical trials of agents purported to inhibit root caries, preselection criteria for the study population should consider the subjects' ages and past history of root lesions.

The surface-specific caries pattern of participants in a school-based fluoride mouthrinsing program with implications for the use of sealants.

This paper describes the surface-specific changes in the DMFS after seven years of a school-based mouthrinsing program occurring in the elementary schools of the fluoride-deficient Three Village Central School District, Long Island, New York. The effectiveness of mouthrinsing was evaluated annually by comparing the caries prevalence of a random sample of participants to that of Three Village elementary schoolchildren examined in 1975, prior to the beginning of the program. Because sixth-grade children rinsed the longest and had the longest exposure to the caries challenge, only sixth-grade children who participated in the program are included in the analysis. Overall, they experienced a 50 percent reduction in dental caries; the reduction was not uniformly experienced by all surfaces. Proximal surface caries showed the greatest rate of change but the least absolute change, because the amount of proximal carious lesions was low initially. Occlusal surfaces showed the greatest absolute reduction in dental caries, whereas buccolingual surfaces had the lowest percentage reduction. The majority of the decayed or filled surfaces, 94 percent, involved pits or fissures. Therefore, it was concluded that the combined use of sealants and weekly fluoride rinsing could produce a virtual elimination of dental decay in elementary schoolchildren.

Longitudinal study of the caries susceptibility of occlusal and proximal surfaces of first permanent molars.

Ten- to 13-year-old children were examined annually for three years to determine the caries activity in the proximal and occlusal surfaces of first permanent molars. Almost every tooth with an unsound (carious or filled) proximal surface also had an unsound occlusal surface. Caries scores in proximal surfaces remained relatively constant and low. The percentage of teeth with occlusal caries or fillings increased throughout the study, even though the teeth had been erupted for seven to ten years by the end of the study. Within the age range studied, the time that teeth were in the mouth had little effect on the vulnerability of occlusal surfaces to caries attack.

The effect of toothbrushing frequency on oral hygiene and gingival health in school children: reassessment after two and one-half years.

An epidemiological survey of brushing frequency, oral hygiene (OHI-S), and gingival condition (GI modified) was conducted on 290, 12- to 15-year-old schoolschildren. The purpose of the survey was to compare the clinical findings with the children's states frequency of toothbrushing. Since the same children had participated in a similar study approximately 2 1/2 years earlier, it was also of interest to determine what effect, if any, a change in reported brushing habits might exert over the oral status of the children. As in a previous study, the stated level of brushing activity was high. Approximately 46 percent of the children claimed to brush twice a day, and 40 percent once a day. The poorest oral hygiene and highest level of gingivitis were associated with the group of children that claimed to brush less than once a day. In general, the children that claimed to brush their teeth more frequently had lower mean OHI-S and GI scores indicating less oral debris and gingivitis. For males-females combined the optimal effect on oral hygiene and gingival condition, on a statistical basis, was detected at the level of twice-daily brushing. Increased brushing frequency beyond this level did not produce significant improvement in OHI-S or GI scores.

Caries prevalence, treatment level, and sealant use related to school lunch program participation.

A total of 2,753 schoolchildren (8-11 years old) from two school districts received visual-tactile examinations for caries. The school districts were approximately 15 miles apart and located in fluoride-deficient (F less than 0.3 ppm) Long Island, New York. The higher socioeconomic community (HSES) had 9.2 percent of its students enrolled in the free or reduced-payment school lunch program; the lower socioeconomic community (LSES) had 50.3 percent enrolled. The LSES community had a higher caries prevalence, more untreated lesions, fewer caries-free children, and fewer children treated with sealants. School lunch programs provide an index to identify communities for dental programs.

Posttreatment benefits from participation in a school-based fluoride mouthrinsing program: II. Results after three to five years of rinsing.

The effect on caries prevalence of previous participation in a school-based 0.2 percent neutral NaF mouthrinsing program was assessed in junior-high-school students. The subjects had rinsed for three-to-five years as elementary-school students in the Three Village fluoride mouthrinsing program, Long Island, New York (F less than or equal to 0.1 ppm). The effects of rinsing were determined by comparing the caries prevalence of seventh, eighth, and ninth grade students who had previously participated in the rinsing program to the baseline caries scores of seventh through ninth grade students who were examined before the rinsing program began. The caries prevalence of the children who had participated in the rinsing program was 29.3 percent (DMFT) and 32.7 percent (DMFS) less than that of the children who had never rinsed. Preferential protection was afforded to the proximal surfaces which had a caries reduction of 56.1 percent compared to 28 percent for both the occlusal and buccolingual surfaces. The duration of the children's participation in the mouthrinsing program generally was related to the level of posttreatment benefits, although age upon entry into the program may also exert an influence. It is fortuitous that there is a persistence of mouthrinsing benefits since older children have generally been reluctant to give their full cooperation in a school-based fluoride mouthrinsing program.

Recruitment of a clinical field trial population: reasons for nonparticipation.

Open-ended telephone interviews were conducted with 294 families who refused participation in a school-based program of professionally applied topical fluoride. While the program was conducted in a flouride-deficient community, the level of topical fluoride contact in the homes of the nonparticipants was high. The traditional antifluoridationist reasons for nonparticipation were not expressed with frequency. Instead, the most frequent reason for returning a negative consent form was that the child was already receiving topical flouride applications from the family dentist. The second most frequent reason was that the child did not wish to participate. Many of the reasons given for nonparticipation were not cogent, suggesting that if the parents had been more informed about the nature of the project and about fluoride in general their responses might have been positive.