The Effect of a Bi-annual Professional Application of APF Foam on Dental Caries Increment in Primary Teeth: 24-month Clinical Trial

Professionally applied fluorides for preventing and arresting dental caries in low- and middle-income countries: Systematic review

OBJECTIVES

This systematic review aimed to review the safety and effectiveness of professionally applied fluorides for preventing and arresting dental caries in low- and middle-income countries (LMICs).

METHODS

Randomized controlled trials conducted in LMICs, in which professionally applied fluorides were compared with placebo/no treatment/health education only or usual care with a minimum one-year follow-up period, were included. Any topically applied fluoride agents such as sodium fluoride (NaF), acidulated phosphate fluoride, silver diamine fluoride (SDF), and nano silver fluoride (NSF) were included. Five databases (PubMed, Embase, Scopus, Web of Science, and Cochrane Library) were searched in May 2022. Meta-analysis was conducted using a random effect model.

RESULTS

This review included 33 studies for qualitative synthesis, encompassing 16,375 children aged between 1.5 and 14 years. Nevertheless, the meta-analysis focused on only 17 studies, involving 4067 children. Fourteen papers assessed potential adverse events, none of which was reported as major adverse events. SDF and NSF were identified as effective in arresting caries on primary teeth (p < 0.05) compared with a placebo or no treatment. Fluoride varnish and gel were identified as effective in reducing new caries development on primary teeth (p < 0.05) but not on permanent teeth (p > 0.05). The certainty of the generated evidence obtained is low.

CONCLUSION

The review provides valuable insights into the use of professionally applied fluorides in LMICs and contributes to recommendations for their use. However, the limited rigorous evidence suggests the need for further research to strengthen these findings and draw more robust conclusions.

Clinical interventions with various agents to prevent early childhood caries: A systematic review with network meta-analysis

BACKGROUND

Dental caries is one of the most prevalent chronic diseases among preschool children globally. Different preventive agents and combinations have been studied. However, the rank of the effectiveness of clinical interventions is equivocal.

AIM

To summarize and rank the effectiveness of clinical interventions using different agents for primary prevention of early childhood caries (ECC).

DESIGN

Two reviewers independently searched PubMed, Embase, and Cochrane Library to identify randomized controlled trials with at least 12-month follow-up. The network meta-analysis (NMA) on different agents was based on a random-effects model and frequentist approach. Standardized mean differences (SMD) with 95% CI of the caries increment were calculated in terms of either dmft or dmfs and used in the NMA. Caries incidences at the child level were compared using odds ratios (ORs) with 95% CI. The effectiveness of the agents was ranked using the surface under the cumulative ranking curve (SUCRA).

RESULTS

After screening 3807 publications and selection, the NMA finally included 33 trials. These trials used either a single or combination of agents such as fluorides, chlorhexidine, casein phosphopeptide-amorphous calcium phosphate, probiotics, xylitol, and triclosan. Compared with control, fluoride foam (FF; SMD -0.69, 95% CI: -1.06, -0.32) and fluoride salt (F salt; SMD -0.66, 95% CI: -1.20, -0.13) were effective in preventing caries increment. Probiotic milk plus low fluoride toothpaste (PMLFTP; OR 0.34, 95% CI: 0.15, 0.77), FF (OR 0.48, 95% CI: 0.37, 0.63), fluoride varnish (FV; OR 0.63, 95% CI: 0.48, 0.81), and fluoride varnish plus high fluoride toothpaste (FVHFTP; OR 0.73, 95% CI: 0.57, 0.93) were effectively preventing caries incidence. According to the SUCRA, FF ranked first in preventing caries increment, whereas PMLFTP ranked first in preventing caries incidence.

CONCLUSION

Fluoride foam, F salt, PMLFTP, FV, and FVHFTP all effectively reduce caries increment or caries incidence in preschool children, but the evidence indicates low degree of certainty. Considering the relatively small number of studies, confidence in the findings, and limitations in the study, clinical practitioners and readers should exercise caution when interpreting the NMA results.

The Safety of Fluoride Compounds and Their Effect on the Human Body-A Narrative Review

Fluoride is one of the elements commonly present in the human environment. Due to its characteristics, it is very widely used in medicine, dentistry, industry or agriculture. On the other hand, its universality possesses a real threat to the human body in the form of acute and chronic poisoning. The aim of this paper is to characterize the properties of fluoride and its effects on the human body, as well as the sources of its occurrence. Particular emphasis is placed on the safety of its use and optimal dosage intake, which prevents accumulation and reduces its potential side effects. The positive effect of proper fluoride supply is widely described. In order to avoid overdose, it is best to consult a specialist to properly select the dosage.

Review of Professionally Applied Fluorides for Preventing Dental Caries in Children and Adolescents

This review aims to evaluate the effectiveness of professional topical fluoride application on the prevention of dental caries in primary and permanent dentition. A web search was conducted for English papers published from 2000 to 2020, using various digital resources (Pubmed, Google Scholar, Cochrane Library, and ResearchGate). The keywords were “professionally applied fluoride”, “fluoride gel”, “fluoride varnish”, “fluoride foam”, “fluoride mouthrinses”, and “non-cavitated caries lesions”. Inclusion criteria: (a) participants: children and adolescents, treated in a dental care setting; (b) intervention: professionally applied fluorides (gel, varnish, foam, mouthrinse); (c) comparator: no professional treatment or other preventive treatments; (d) outcomes: clinical effectiveness (e.g., caries reduction, tooth remineralization); (e) study design: randomized controlled trials, systematic reviews, meta-analyses; (f) publication period: 1 January 2000–31 December 2021. Clinical studies about home-use fluoride products, discussion papers, in-vitro studies, case reports, non-English articles, and studies with unclear methodology were excluded. Topical fluoride applications are indicated for patients with active smooth surface caries and for patients in high caries risk groups. Both APF gel and fluoride varnish are effective and can be recommended for caries prevention in primary and permanent teeth. For children under the age of 6, only 2.26% fluoride varnish is recommended.

Screening and Interventions to Prevent Dental Caries in Children Younger Than 5 Years: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

A 2014 review for the US Preventive Services Task Force (USPSTF) found that oral fluoride supplementation and topical fluoride use were associated with reduced caries incidence in children younger than 5 years.

OBJECTIVE

To update the 2014 review on dental caries screening and preventive interventions to inform the USPSTF.

DATA SOURCES

Ovid MEDLINE, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews (to September 2020); surveillance through July 23, 2021.

STUDY SELECTION

Randomized clinical trials (RCTs) on screening, preventive interventions, referral to dental care; cohort studies on screening and referral; studies on diagnostic accuracy of primary care oral examination or risk assessment; and a systematic review on risk of fluorosis included in prior USPSTF reviews.

DATA EXTRACTION AND SYNTHESIS

One investigator abstracted data; a second checked accuracy. Two investigators independently rated study quality.

RESULTS

Thirty-two studies (19 trials, 9 observational studies, and 4 nonrandomized clinical intervention studies [total 106 694 participants] and 1 systematic review [19 studies]) were included. No study evaluated effects of primary care screening on clinical outcomes. One study (n = 258) found primary care pediatrician examination associated with a sensitivity of 0.76 (95% CI, 0.55 to 0.91) and specificity of 0.95 (95% CI, 0.92 to 0.98) for identifying a child with cavities, and 1 study found a risk assessment tool associated with sensitivity of 0.53 and specificity of 0.77 (n = 697, CIs not reported) for a child with future caries. No new trials of dietary fluoride supplementation were identified. For prevention, topical fluoride compared with placebo or no topical fluoride was associated with decreased caries burden (13 trials, n = 5733; mean caries increment [difference in decayed, missing, and filled teeth or surfaces], -0.94 [95% CI, -1.74 to -0.34]) and likelihood of incident caries (12 trials, n = 8177; RR, 0.80 [95% CI, 0.66 to 0.95]; absolute risk difference, -7%) in higher-risk populations or settings, with no increased fluorosis risk. Evidence on other preventive interventions was limited (education, xylitol) or unavailable (silver diamine fluoride), and no study directly evaluated primary care dentistry referral vs no referral.

CONCLUSIONS AND RELEVANCE

There was no direct evidence on benefits and harms of primary care oral health screening or referral to dentist. Dietary fluoride supplementation and fluoride varnish were associated with improved caries outcomes in higher-risk children and settings.

Topical fluoride to prevent early childhood caries: Systematic review with network meta-analysis

OBJECTIVES

To summarize the evidence on prevention of early childhood caries (ECC) by professionally or self-applied topical fluorides using network meta-analysis.

DATA

Randomized-controlled trials with minimum 1-year follow-up assessing caries-preventive effect among children younger than six years.

SOURCES

Eight electronic databases and grey literature.

STUDY SELECTION

After screening and data extraction, risk of bias assessment using Cochrane risk of bias tool 2.0 was done. Twenty-four trials were included, among which 17 were assessed as "high risk" and remaining as "low risk". Fifteen studies evaluated professionally-applied, and the other nine used self-applied topical fluorides. Ten studies on professionally-applied fluorides reporting the net caries increment (dmfs increment) at 2-years follow-up were included in Network meta-analysis (NMA). NMA and ranking the interventions were conducted using a frequentist random-effects approach and surface under the cumulative ranking command, followed by assessing the certainty of evidence using an extension of GRADE approach with CINeMA framework. Among the eight included interventions of professionally-applied fluorides, only two, i.e., 3-monthly 0.9% difluorosilane (DFS) and 6-monthly 5% sodium fluoride varnish were effective in preventing ECC compared to control with 3-monthly DFS application ranking higher than 6-monthly sodium fluoride varnish application.

CONCLUSION

Among all the professionally-applied topical fluoride interventions reviewed, very low to moderate evidence was found with 0.9% DFS application at 3-monthly intervals, which was ranked highest in prevention of ECC. Among the included studies on self-applied topical fluorides, the evidence was inconclusive due to heterogeneity among studies.

CLINICAL SIGNIFICANCE

The 0.9% DFS varnish applied every 3 months is most effective for preventing early childhood caries. The review recommends that good quality studies be conducted in future, comparing two or more interventions for both self- as well as professionally-applied topical fluoride agents with adequate follow-up.

Effectiveness of Fluoridation Depending on Periodicity in 6–10-year-old Children

Background

The cost-effectiveness of this study was achieved in the group that was treated every three months with periodic intervals, which had a reduction of caries with 62%. The relative effectiveness of our study is the application of fluoride treatment every 3 months compared with treatments done every 4 and 6 months, respectively.

Objective

To evaluate the reduction of caries disease depending on the time period of fluoride gel application. The sample was chosen randomly.

Main hypothesis

The frequency of fluoride gel application every 3 months has positive impacts on reducing dental caries.

Basic design

This is a cross-sectional study with a controlled sample for a period of 24 months. Durashield fluoride fluid (5% sodium fluoride) was used for the treatment of permanent dentition of the 6–10-year-old children.

Clinical setting

This study proves that fuoride application every 3 months significantly reduces caries morbidity.

Participants

Our study included 400 children, who were divided into 4 groups, 100 children in each group.

Intervention

The first group did not undergo any treatment and it is called the control group. The second group was under fluoride treatment every 4 months. The third group was treated with fluoride every 3 months, and the fourth group was treated every 6 months.

Results

The data collected from the control group showed that there is an increase in 24% of the caries incidence. In the group treated with fluoride every 4 months, caries incidence decreased to 30%. The group treated every 3 months with periodic intervals had a reduction of caries with 62%, while the group treated every 6 months had a reduction of 40%. Based on the analysis of variance (ANOVA) test, the fluoridation application every 3 months is significant for p = 0.000.

Conclusion

The best results were achieved in the treatment with fluoride in a 3-month periodic interval.

How to cite this article

Canga M, Malagnino VA et al. Effectiveness of Fluoridation Depending on Periodicity in 6–10-year-old Children. Int J Clin Pediatr Dent 2019;12(4):280–282.

Assessment of Inhibition of Mineral Loss from Human Tooth Enamel by Carbon Dioxide Laser and 1.23% Acidulated Phosphate Fluoride

Aims and Objectives

The efficacy of carbon dioxide (CO₂) laser irradiation combined with fluoride in inhibiting enamel demineralization has been demonstrated by several laboratory investigations. However, there are very few reports about the in situ or in vivo caries preventive effect of CO₂ laser combined with topical fluoride on dental enamel. Hence, an in situ study was designed and carried out to assess inhibition of mineral loss from human tooth enamel by CO₂ laser and 1.23% acidulated phosphate fluoride (APF).

Material and Methods

Impressions of upper and lower arch of the volunteers were made in alginate impression material. Study models were poured, duplicated, and duly labeled. On the working model, appliances were fabricated in acrylic resin to fit the upper dental arch of the volunteers. Four enamel slabs (one from each group) were fitted on the palatal surface of the appliance as close as possible to posterior teeth. Surfaces of slabs were kept below the outer surface of acrylic. The analysis was done using SPSS version 15 (SPSS Inc., Chicago, IL, USA) Windows software program.

Results

Statistically significant increase in inhibition of mineral loss of enamel slabs when treated individually or in a combination of low power CO₂ laser and 1.23% APF solution. The application of 1.23% APF solution after low power CO₂ laser treatment showed maximum inhibition of mineral loss.

Conclusion

The combined use of this specific laser treatment plus fluoride was more successful than either laser treatment or fluoride alone in the inhibition of mineral loss in the mouth. The results of this study also suggest that the combination of low power laser treatment with fluoride therapy may be effective as a caries inhibition treatment.

Longitudinal investigation of salivary proteomic profiles in the development of early childhood caries

OBJECTIVES

To investigate differentially expressed salivary peptides in the development of early childhood caries (ECC) in 3-4 year-old children.

MATERIALS AND METHODS

Eighty-two caries-free children at baseline were followed-up for 1year, during which period 15 of them had developed ECC (Group C), whilst another 15 cases out of the 31 individuals who remained healthy were marked as Group H. Stimulated whole saliva samples were collected at 0, 6 and 12 months, and analyzed using weak cation exchange magnetic beads combined with matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Corresponding peptide mass fingerprints were obtained to develop a discriminating model for ECC development. Q-Exactive mass spectrometry was then performed to identify the possible proteins where these peptides might derive from.

RESULTS

Nine peptide peaks were found to be significantly different in Group C among the three sampling time points and might correlate with development of caries. Levels of three of them increased over time, whilst that of the other six decreased gradually. We chose three peptides (1346.6, 2603.5 and 3192.8Da) which exhibited the best capability of classification, to establish a model for children at high risk of caries. One peptide (1346.6Da) was identified to be salivary histatin-rich peptide.

CONCLUSIONS

Our results indicate that peptidomic methods can be applied to help identify new candidate biomarkers for the occurrence and development of ECC.

CLINICAL SIGNIFICANCE

The change of salivary peptides may be an indicator of ECC, facilitating more effective measures to be taken in prevention of this disease.

CO2 laser and topical fluoride therapy in the control of caries lesions on demineralized primary enamel

This study evaluated the effect of CO₂ laser irradiation and topical fluoride therapy in the control of caries progression on primary teeth enamel. 30 fragments (3 × 3 × 2 mm) from primary canines were submitted to an initial cariogenic challenge that consisted of immersion on demineralizing solution for 3 hours and remineralizing solution for 21 hours for 5 days. Fragments were randomly assigned into three groups (n = 10): L: CO₂ laser (λ = 10.6 μm), APF: 1.23% acidulated phosphate fluoride, and C: no treatment (control). CO₂ laser was applied with 0.5 W power and 0.44 J/cm² energy density. Fluoride application was performed with 0.1 g for 1 minute. Cariogenic challenge was conducted for 5 days following protocol previously described. Subsurface Knoop microhardness was measured at 30 μm from the edge. Obtained data were subjected to analysis the variance (ANOVA) and Duncan test with significance of 5%. It was found that the L group showed greater control of deciduous enamel demineralization and were similar to those of APF group, while being statistically different from C group (P ≤ 0.05) that showed the lowest microhardness values. It was concluded that CO₂ laser can be an additional resource in caries control progression on primary teeth enamel.

Staining potential of acidulated phosphate fluoride (APF) foam on dental restorations in vitro

Objectives:

To identify the staining potential of acidulated phosphate fluoride (APF) foam on restorations in vitro.

Materials and Methods:

Two hundred ovine molars were used. Except 40 teeth remained unrestored as the controls, each was randomly selected to receive one of four restorative materials including preparation without restoration, glass ionomer cement (GIC), resin modified glass ionomer cement (RMGIC), or composite resin (CR). Following the procedure, topical APF was applied with a predetermined frequency. Staining formation was then evaluated.

Results:

APF-treated teeth and restorations appeared with a darker shade, an orange-colored surface and/or a brown margin. The staining rates on GIC, RMGIC, and CR were 50%, 27.5%, and 17.5%, respectively. GIC had a higher staining potential than RMGIC (χ² = 4.266, df = 1, P = 0.039) and CR (χ² = 9.448, df = 1, P = 0.002), whereas the difference between RMGIC and CR was indiscernible (χ² = 1.147, df = 1, P = 0.284). Repeated applications of topical APF increased the risk of staining on RMGIC (χ² = 8.436 df = 1, P = 0.004) and CR (χ² = 6.873, df = 1, P = 0.009) but not on GIC (χ² = 0, df = 1, P = 1) and the controls (χ² = 4.051, df = 3, P = 0.256).

Conclusions:

APF-foam-related staining was confirmed in vitro. GIC was more susceptible to fluoride staining. This study suggested aesthetic implications when applying fluorides to restored teeth.

New proposal of silver diamine fluoride use in arresting approximal caries: study protocol for a randomized controlled trial

BACKGROUND

Approximal surfaces are a challenge to caries lesions control. Silver diamine fluoride (SDF) is a simple,low-cost and promisor intervention for arresting caries lesions, but it has never been tested on approximal surfaces. Our aim is to evaluate the efficacy and cost-efficacy of SDF in arresting initial lesions compared to resin infiltration and exclusively flossing (control group). Our second aim is to assess discomfort and satisfaction regarding interventions.

METHODS/DESIGN

This is a randomized clinical trial, double-blinded, placebo-controlled study. Children/adolescents presenting at least one approximal initial caries lesion in primary molars/permanent premolars and molars will be included. Surfaces with advanced dentine lesions identified by radiography and participants who refuse to participate or present negative behaviors will be excluded. A minimum sample size of 504 surfaces will be required for each subgroup. Individuals will be randomly allocated in three groups of interventions: SDF, resin infiltration, and control group. Depending on the allocation, the patients will receive the active treatment and respective placebo therapies. All patients will be oriented to daily flossing the included surfaces. Our primary outcome will be caries progression by clinical and radiographic examinations. Appointments will be timed and costs of materials will be considered to calculate cost-efficacy. Patient discomfort will be assessed after interventions. Parent and patient satisfaction with the treatment will be collected after treatment and in the last follow-up visit. Individuals will be assessed at 1 and 3 months after treatment to evaluate dental biofilm and at 6, 12, and 24 months to assess caries progression by visual examination and/or radiography. Multilevel analyses will be used to verify if the type of treatment influenced on the tested outcomes. Costs will be compared and analyses of cost-efficacy will be performed. Poisson analysis will test the association between intervention and reported discomfort and satisfaction.

DISCUSSION

Our hypothesis is that SDF is the most cost-efficacious option from all tested interventions. If our hypothesis is confirmed, the use of SDF in private and public contexts could represent an easier and effective option in the treatment of enamel approximal caries in children/adolescents.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01477385), Initial release: 11/16/2011: last update: 06/02/2014.

Preventing dental caries in children <5 years: systematic review updating USPSTF recommendation

BACKGROUND AND OBJECTIVE

Screening and preventive interventions by primary care providers could improve outcomes related to early childhood caries. The objective of this study was to update the 2004 US Preventive Services Task Force systematic review on prevention of caries in children younger than 5 years of age.

METHODS

Searching Medline and the Cochrane Library (through March 2013) and reference lists, we included trials and controlled observational studies on the effectiveness and harms of screening and treatments. One author extracted study characteristics and results, which were checked for accuracy by a second author. Two authors independently assessed study quality.

RESULTS

No study evaluated effects of screening by primary care providers on clinical outcomes. One good-quality cohort study found pediatrician examination associated with a sensitivity of 0.76 for identifying a child with cavities. No new trials evaluated oral fluoride supplementation. Three new randomized trials were consistent with previous studies in finding fluoride varnish more effective than no varnish (reduction in caries increment 18% to 59%). Three trials of xylitol were inconclusive regarding effects on caries. New observational studies were consistent with previous evidence showing an association between early childhood fluoride use and enamel fluorosis. Evidence on the accuracy of risk prediction instruments in primary care settings is not available.

CONCLUSIONS

There is no direct evidence that screening by primary care clinicians reduces early childhood caries. Evidence previously reviewed by the US Preventive Services Task Force found oral fluoride supplementation effective at reducing caries incidence, and new evidence supports the effectiveness of fluoride varnish in higher-risk children.

Argon and Nd:YAG lasers for caries prevention in enamel

OBJECTIVE

The aim of this study was to investigate the effect of Nd:YAG and argon laser irradiations on enamel demineralization after two different models to induce artificial caries.

BACKGROUND DATA

It is believed that the use of the high-intensity laser on the dental structure can lead to a more acid-resistant surface.

MATERIALS AND METHODS

Twenty-one extracted human third molars were sectioned into tooth quarters. The quarters were distributed in three groups: Group I (control), untreated; Group II, Nd:YAG laser (60 mJ, 15 pps, 47.77 J/cm(2), 30 sec); and Group III, argon laser (250 mW, 12 J/cm(2), 48 sec). Tooth quarters from each group were subjected to two different demineralization models: cycle 1, a 14 day demineralization (pH 4.5; 6 h) and remineralization (pH 7.0; 18 h) solutions, 37 °C and cycle 2, 48 h in demineralization solution (pH 4.5). Samples were prepared in slices (60-100 μm thick) to be evaluated under polarized light microscopy. Demineralization areas were measured (mm(2)) (n=11). Data were analyzed by ANOVA and Tukey's test (p<0.05).

RESULTS

Means followed by different letters are significantly different: 0.25 A (control, cycle 48 h); 0.18 AB (control, cycle 14 days); 0.17 AB (Nd:YAG, cycle 14 days); 0.14 BC (argon, cycle 48 h); 0.09 BC (Nd:YAG, cycle 48 h), and 0.06 C (argon, cycle 14 days).

CONCLUSIONS

The argon laser was more effective for caries preventive treatment than Nd:YAG laser, showing a smaller demineralization area in enamel.

Effect of CPP-ACP paste on dental caries in primary teeth: a randomized trial

This clinical trial tested the effect of daily application of 10% w/v calcium phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste for 1 yr when added to regular toothbrushing with fluoridated toothpaste to prevent dental caries in pre-school children. High-caries-risk children aged 2½ to 3½ yrs in a suburban area of central Thailand were assigned to receive either CPP-ACP (n = 150) or a placebo control (n = 146) in addition to fluoridated toothpaste. The International Caries Detection and Assessment System (ICDAS) was recorded at baseline, 6 mos, and 1 yr. At 1 yr, a significant increase in mean numbers of enamel and dentin caries lesions, as well as dmfs, was found in both groups (p < 0.001). No significant difference was observed between groups on these 3 outcome measures (p = 0.23, 0.84, and 0.91, respectively). The odds of enamel caries lesion transitions to a state of regression or stability, compared with progression from baseline, was also not different between groups [OR = 1.00, 95% CI (0.86, 1.17)]. This trial found that daily application of 10% w/v CPP-ACP paste on school days for 1 yr, when added to regular toothbrushing with a fluoride toothpaste, had no significant added effect in preventing caries in the primary dentition of these pre-school children (ClinicalTrials.gov number CT01 604109).

Quality of cluster randomized controlled trials in oral health: a systematic review of reports published between 2005 and 2009

OBJECTIVES

To assess the quality of methods and reporting of recently published cluster randomized trials (CRTs) in oral health.

METHODS

We searched PubMed for CRTs that included at least one oral health-related outcome and were published from 2005 to 2009 inclusive. We developed a list of criteria for assessing trial quality and reporting. This was influenced largely by the extended CONSORT statement for CRTs but also included criteria suggested by other authors. We examined the extent to which trials were consistent with these criteria.

RESULTS

Twenty-three trials were included in the review. In 15 (65%) trials, clustering had been accounted for in sample size calculations, and in 18 (78%) authors had accounted for clustering in analysis. Intraclass correlation coefficients (ICCs) were reported for eight (35%) trials; the outcome assessor was reported as having been blinded to allocation in 12 (52%) trials; 17 (74%) described eligibility criteria at individual level, but only nine (39%) described such criteria at cluster level. Sixteen of 20 trials (80%), in which individuals were recruited, reported that individual informed consent was obtained.

CONCLUSIONS

These results suggest that the quality of recent CRTs in oral health is relatively high and appears to compare favourably with other fields. However, there remains room for improvement. Authors of future trials should endeavour to ensure sample size calculations and analyses properly account for clustering (and are reported as such), consider the potential for recruitment/identification bias at the design stage, describe the steps taken to avoid this in the final report and report observed ICCs and cluster-level eligibility criteria.

Effect of long-term fluoride exposure on lipid peroxidation and histology of testes in first- and second-generation rats

This experiment was designed to investigate the histological and lipid peroxidation effects of chronic fluorosis on testes tissues of first- and second-generation rats. Sixteen virgin female Wistar rats were mated with eight males (2:1) for approximately 12 h to obtain first-generation rats. Pregnant rats were divided into two groups: controls and fluoride-given group, each of which containing five rats. Pregnant rats in the fluoride-given group were exposed to a total dose of 30 mg/l sodium fluoride (NaF) in commercial drinking water containing 0.07 mg/l of NaF throughout the gestation and lactation periods. After the lactation period, the young animals (first generation, F1) were exposed to the same dose of NaF in drinking water for 4 months. At the end of the 4 months of experimental period, nine randomly chosen male rats (F1) were killed and testes tissues were taken for histopathological and biochemical analysis. The remaining eight female rats were mated with four males (2:1) for approximately 12 h to obtain second-generation rats. Six female were identified as pregnant and treated with similarly throughout the gestation and the lactation periods. After the lactation period, the young male animals (second generation, F2) were also treated in the same way for 4 months. At the end of the 4 months of experimental period, nine randomly chosen male rats (F2) were killed and testes tissues were collected for histopathological and biochemical analysis. The rats in the control group were applied the same procedure without NaF administration. In biochemical analysis of the fluoride given F1 and F2 rats, it has been found that plasma fluoride levels and testes thiobarbituric acid reactive substance levels were significantly increased when compared with the control group. In F1 and F2 rats, similar histopathological changes were observed. In both groups, spermatogenesis was severely reduced. Spermatogonia and primary spermatocytes were normal, however, there was a widespread degeneration in other spermatogenic cell lines of the seminiferous epithelium. The histological structures of the Sertoli and interstitial Leydig cells were normally observed. It is concluded that chronic fluorosis exposure leads to a remarkable destruction in testes tissues of F1 and F2 rats via lipid peroxidation.

Multilevel analysis of group-randomized trials with binary outcomes

OBJECTIVES

Many dental studies have assessed the effectiveness of community- or group-based interventions such as community water fluoridation. These cluster trials, of which group-randomized trials (GRTs) are one type, have design and analysis considerations not found in studies with randomization of treatments to individuals (randomized controlled trials, RCTs). The purpose of this paper is to review analytic methods used for the analysis of binary outcomes from cluster trials and to illustrate these concepts and analytical methods using a school-based GRT.

METHODS

We examine characteristics of GRTs including intra-class correlation (ICC), their most distinctive feature, and review analytical methods for GRTs including group-level analysis, adjusted chi-square test and multivariable analysis (mixed effect models and generalized estimating equations) for correlated binary data. We consider two- and three-level modeling of data from a cross-sectional cluster design. We apply the concepts reviewed using a GRT designed to determine the effect of incentives on response rates in a school-based dental study. We compare the results of analyses using methods for correlated binary data with those from traditional methods that do not account for ICC.

RESULTS

Application of traditional analytic methods to the dental GRT used as an example for this paper led to a substantial overstatement of the effectiveness of the intervention.

CONCLUSIONS

Ignoring the ICC among members of the same group in the analysis of public health intervention studies can lead to erroneous conclusions where groups are the unit of assignment. Special consideration is needed in the analysis of data from these cluster trials. Randomization of treatments to groups also should receive more consideration in the design of cluster trials in dental public health.

Professionally applied topical fluoride

BACKGROUND

With the dramatic increase in the amount of scientific information available about oral health, an evidence-based approach to oral health care and the practice of dentistry is necessary. There is a need to summarize, critique and disseminate scientific evidence and to translate the evidence into a practical format that is used easily by dentists The evidence-based clinical recommendations in this report were developed by an expert panel established by the American Dental Association Council on Scientific Affairs that evaluated the collective body of scientific evidence on the effectiveness of professionally applied topical fluoride for caries prevention. The recommendations are intended to assist dentists in clinical decision making.

TYPES OF STUDIES REVIEWED

MEDLINE and the Cochrane Library were searched for systematic reviews and clinical studies of professionally applied topical fluoride--including gel, foam and varnish--through October 2005.

RESULTS

Panelists were selected on the basis of their expertise in the relevant subject matter. The recommendations are stratified by age groups and caries risk and indicate that periodic fluoride treatments should be considered for both children and adults who are at moderate or high risk of developing caries. Included in the clinical recommendations is a summary table that can be used as a chairside resource.

CLINICAL IMPLICATIONS

The dentist, knowing the patient's health history and vulnerability to oral disease, is in the best position to make treatment decisions in the interest of each patient. These clinical recommendations must be balanced with the practitioner's professional expertise and the individual patient's preferences.