Fluoride

BACKGROUND:
This article presents evidence-based clinical recommendations regarding the intake of fluoride from reconstituted infant formula and its potential association with enamel fluorosis. The recommendations were developed by an expert panel convened by the American Dental Association (ADA) Council on Scientific Affairs (CSA). The panel addressed the following question: Is consumption of infant formula reconstituted with water that contains various concentrations of fluoride by infants from birth to age 12 months associated with an increased risk of developing enamel fluorosis in the permanent dentition?

TYPES OF STUDIES REVIEWED:
A panel of experts convened by the ADA CSA, in collaboration with staff of the ADA Center for Evidence-based Dentistry (CEBD), conducted a MEDLINE search to identify systematic reviews and clinical studies published since the systematic reviews were conducted that addressed the review question.

RESULTS:
CEBD staff identified one systematic review and two clinical studies. The panel reviewed this evidence to develop recommendations.

CLINICAL IMPLICATIONS:
The panel suggested that when dentists advise parents and caregivers of infants who consume powdered or liquid concentrate infant formula as the main source of nutrition, they can suggest the continued use of powdered or liquid concentrate infant formulas reconstituted with optimally fluoridated drinking water while being cognizant of the potential risks of enamel fluorosis development. These recommendations are presented as a resource to be considered in the clinical decision-making process. As part of the evidence-based approach to care, these clinical recommendations should be integrated with the practitioner’s professional judgment and the patient’s needs and preferences.

We conducted a school-based parallel cluster randomized controlled trial with 36-month follow-up of children aged 7 to 8 years. Primary schools were randomly assigned to 2 groups: 3 applications of fluoride varnish (22,600 ppm) each year or no intervention. The primary outcome was DFS increment in the first permanent molars, with the hypothesis that 9 applications of varnish over 3 years would result in a lower increment in the test group. Follow-up measurements were recorded by examiners blind to the allocation. Ninety-five schools were randomized to the test and 95 to the reference groups; 1473 (test) and 1494 (reference) children participated in the trial. An intention-to-treat analysis was carried out with random effects models. The DFS increment was 0.65 (SD 2.15) in the test and 0.67 (SD 2.10) in the reference groups, respectively. There was no statistically significant difference between the groups. We were unable to demonstrate an effect for fluoride varnish when it was used as a public health intervention to prevent caries in the first permanent molar teeth (Inter-national Standard Randomized Controlled Trial Registration: ISRCTN: #72589426).

Although fluoridation of drinking water for the purpose of caries prevention is widely practiced in the United States and a few other countries, and is strongly encouraged by some governments and public health agencies, several important concerns have not been adequately addressed.

These comments on recent reports from the U.S. Environmental Protection Agency’s Office of Water are submitted to the EPA in response to their January 7, 2011 announcements (EPA 2011a, b)

These comments are submitted to the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) in response to their July 2011 report, ―Evidence on the Carcinogenicity of Fluoride and Its Salts.

BACKGROUND:
In this article, the authors present evidence-based clinical recommendations regarding the use of nonfluoride caries preventive agents. The recommendations were developed by an expert panel convened by the American Dental Association (ADA)Council on Scientific Affairs. The panel addressed several questions regarding the efficacy of nonfluoride agents in reducing the incidence of caries and arresting or reversing the progression of caries.

TYPES OF STUDIES REVIEWED:
A panel of experts convened by the ADA Council on Scientific Affairs, in collaboration with ADA Division of Science staff, conducted a MEDLINE search to identify all randomized and nonrandomized clinical studies regarding the use of non fluoride caries-preventive agents.

RESULTS:
The panel reviewed evidence from 50 randomized controlled trials and 15 nonrandomized studies to assess the efficacy of various nonfluoride caries-preventive agents.

CLINICAL IMPLICATIONS:
The panel concluded that certain nonfluoride agents may provide some benefit as adjunctive therapies in children and adults at higher risk of developing caries. These recommendations are presented as a resource for dentists to consider in the clinical decision-making process. As part of the evidence based approach to care, these clinical recommendations should be integrated with the practitioner’s professional judgment and the patient’s needs and preferences.

The requirements for an ideal restorative material include adhesion to tooth structure (enamel and dentine) and an ability to withstand the traumas of occlusion. However, some level of an anticaries effect is also desirable. After a long history of glass-ionomer cement (GIC) development, an evidence base in support of the therapeutic effect of GIC, particularly with regard to its anticaries effect, is emerging. This evidence is increasingly presented through systematic reviews of clinical GIC application and, to a certain extent, relates to a caries-preventive effect of the material itself. However, the strength of evidence supporting other aspects of GIC, such as a higher remineralizing effect, fluoride uptake in hard tooth tissue and fluoride release of GIC, is limited. Nevertheless, the results of these in situ and laboratory trials provide valuable insights into factors that facilitate understanding of the clinical efficacy of GIC.

The body weights and organic somatic index of brain in the sodium fluoride treated animals were significantly reduced, relative to the control group. Tissue fluoride levels of hippocampus, neocortex, cerebellum, spinal cord and sciatic nerve, all increased significantly in fluoride treated rats. Electron microscopy of the hippocampus, neocortex, cerebellum, spinal cord and sciatic nerve showed neurodegenerative changes in the NaF treated group compared to controls. Axon deterioration, myelin sheath degeneration and dark cells with scanty cytoplasm were observed in spinal cord and sciatic nerve in the treated group. Other distinctive morphological alterations observed were: vacuolated swollen mitochondria in neocortex, hippocampus and cerebellum; myelinated fibers with breaks in continuity (axon partly preserved and partly vacuolated) in hippocampus; myelin splitting and vacuolated schwann cell within the cerebellum and sciatic nerve respectively. Thus, neurodegeneration was clearly evident in the hippocampus, neocortex, cerebellum, spinal cord and sciatic nerve on fluoride exposure.

Glass-ionomer cement (GIC) materials have been in clinical use since their inception 40 years ago. They have undergone several permutations to yield different categories of these materials. Although all GICs share the same generic properties, subtle differences between commercial products may occur. They have a wide range of uses such as lining, bonding, sealing, luting or restoring a tooth. In general, GICs are useful for reasons of adhesion to tooth structure, fluoride release and being tooth-coloured although their sensitivity to moisture, inherent opacity, long-term wear and strength are not as adequate as desired. They are useful in situations where they are not disadvantaged by their comparatively lower physical properties, such as where there is adequate remaining tooth structure to support the material and where they are not subject to heavy occlusal loading. The last decade has seen the use of these materials being extended. However, they are likely to retain their specific niches of clinical application.