Impact of biannual treatment with fluoride varnish on tooth-surface-level caries progression in children aged 1–3 years

Abstract

Objective

This study describes caries progression at tooth-surface level in children from 1 to 3 years of age and the impact of biannual treatment with fluoride varnish.

Methods

Children who participated in a cluster-randomized controlled trial and had shown signs of dental caries were included in this study (n = 801). International Caries Detection and Assessment System (ICDAS) was used to classify dental caries. The present study compared children receiving a standard yearly intervention to children receiving the same standard preventive intervention supplemented with an application of fluoride varnish every half year.

Results

The maxillary incisors were the first teeth to develop cavitation (ICDAS 3–6) and also mostly affected. Further analyses focusing on maxillary incisors buccal surfaces showed that sound surfaces had least progression and that progression to extensive decay was more common in teeth that had exhibited moderate decay. A summarizing progression index (PI) was calculated for the buccal surfaces of the maxillary incisors. Between 1 and 2 years of age PI was 26% and between 2 and 3 years of age PI was 21%. The progression on buccal incisors and on occlusal first primary molars did not differ between intervention groups (p ≤ 0,05).

Conclusion

No impact on caries progression for biannual treatment with fluoride varnish was found. Clinical significance: Using fluoride varnish as a complement to standard intervention in toddlers did not add in the prevention of dental caries or its progression. The education of parents in the use fluoride toothpaste as they start brushing the teeth of their children is essential.

Introduction

Dental caries is a common disease among children and adolescents, and the distribution of caries is reported unequal in highly developed countries . Despite a long tradition of dental care and well-established preventive measures, caries occurs in 5% of 2-year-olds and 23% of 3-year-olds in certain high-risk areas of Stockholm, Sweden . Particularly children with immigrant background are at risk, in a Swedish study 59% of the 4-year-old children with immigrant background had developed dental caries .

Reports indicate that children who present any sign of dental caries at 2.5 years of age have a more than 90% risk of developing a new lesion within a year . In preschool children, dental caries progresses rapidly compared to young permanent teeth, the progression rate in primary teeth is twice as fast . The thinner enamel and the diverse enamel structure in primary teeth may contribute to the difference in progression rate . A newly published study using the ICDAS found the rates of progression to a moderate-stage lesion for a surface with an initial lesion to be 9.6 times higher than for surfaces that were sound at baseline. and rates of progression to an extensive lesion for surfaces with a moderate-stage lesion to be 20.6 times higher than for surfaces sound at baseline; these results highlight the importance of secondary prevention .

Fluoride varnish is an important tool in prevention of dental caries . Evidence-based guidelines recommend professional application of 2.25% fluoride varnish at least twice a year in children younger than 6 at risk of developing dental caries . Recently, evidence is accumulating questioning this concept. In a 3-year longitudinal study, we were unable to find any additive effect of biannual fluoride varnish as a supplement to a standard preventive program .

Certain surfaces seem to gain most from topical fluoride treatment , but there is still a lack of knowledge about fluoride’s therapeutic effects .

The aim of this study was to analyze and describe caries progression on tooth surface level in patients between age 1 and 3 years using the ICDAS, and to investigate the impact of biannual treatment with fluoride varnish on caries progression. Our hypothesis was that caries progression in the buccal maxillary incisors would be lower in patients receiving a biannual fluoride varnish program compared to those given a standard preventive program.

Subjects and methods

This longitudinal study is part of the “Stop Caries Stockholm” project, a cluster-randomized controlled field trial that evaluated the effect of fluoride varnish applications on caries development in toddlers living in multicultural areas in greater Stockholm, Sweden. The project started in 2011 and collected data over 3 years. At baseline, 3403 1-year-old children participated and attended yearly follow-ups until they reached 3 years of age. For a full description of the trial, see .

The present study included all children in this sample diagnosed with dental caries (ICDAS 1–6) in any of their examinations from baseline until 3 years of age (n = 801). Table 1 describes baseline characteristics of the sample and Fig. 1 presents a flow chart of the process for selecting children to participate in the caries-progression analyses. The regional ethics committee approved the study 20110119 Daybook no. 2010/1956-31/4 and the children’s parents signed informed-consent forms. The study is registered at www.controlled-trials.com (ISRCTN35086887).

Table 1
Baseline characteristics of the participating children in the test and the reference groups (n = 801).
Variable Reference group n = 375 (%) Test group n = 426 (%)
Girls/boys 53/47 53/47
Immigrant a 87 88
Mothers’ education (<9 years) 28 27
Family income (<SEK b 20.000/month) 50 50
Tooth-brushing every day 54 46
Sweet drinks (>2/day) 15 13
Candy(>1/week) 14 11

a Other language than Swedish spoken at home.

b Swedish crowns.

Fig. 1
Flow chart of children in the progression analyses.

Intervention

The two parallel arms of the study comprised a test and a reference group. Children in the test group received a standard oral health program supplemented with biannual fluoride varnish applications (Duraphat ® , 22.6 mg of fluoride per ml, Colgate-Palmolive) between 1 and 3 years of age. The reference group, who received the standard oral health program including oral health information and a toothbrush and a tube of toothpaste (1000–1450 ppm fluoride), free of charge, at the annual examination.

Clinical examination

Trained examiners (n = 49) assessed dental caries using the ICDAS criteria, ranging from 0 to 6 . Interexaminer reliability was calculated and ranged between ĸ = 0.42 and 0.60 for ICDAS 0–6. With ICDAS 3 as cut-off for cavitation interexaminer reliability ranged between ĸ = 0.61 and 0.73. A more detailed description has been published earlier . None of the examiners had access to previous assessment protocols for the study subjects. They examined the teeth using optimal light, a dental mirror, and a probe with a ball-ended tip after removing excess saliva with a cotton roll. Before examination, the children’ teeth were cleaned with a toothbrush. Due to the young age of the children, it was difficult to consistently accomplish air drying for 5 s.

Statistical analysis

Statistical analyses used IBM SPSS software (version 22.0). For descriptive purposes, we present both crude and relative frequencies. To describe prevalence and surface-level distribution of cavitation, we defined the threshold for cavitation as an ICDAS score of 3 . Cross-referenced tables show caries progression. The chi-square test assessed differences in caries progression between the test and reference groups, with p < 0.05 set as the threshold for statistical significance.

To avoid compromising the results of the analysis of progression on buccal surfaces, we chose to exclude some surface values that seemed misclassified, specifically values that showed regression from ICDAS 3–6 to ICDAS 0. At 24 months, we excluded 0.6% of the surfaces and at 36 months, 5.1% of the surfaces. We tested the differences in excluded surface values between the test and the reference groups using kappa analyses and found no significant differences ( p = 0.30).

Subjects and methods

This longitudinal study is part of the “Stop Caries Stockholm” project, a cluster-randomized controlled field trial that evaluated the effect of fluoride varnish applications on caries development in toddlers living in multicultural areas in greater Stockholm, Sweden. The project started in 2011 and collected data over 3 years. At baseline, 3403 1-year-old children participated and attended yearly follow-ups until they reached 3 years of age. For a full description of the trial, see .

The present study included all children in this sample diagnosed with dental caries (ICDAS 1–6) in any of their examinations from baseline until 3 years of age (n = 801). Table 1 describes baseline characteristics of the sample and Fig. 1 presents a flow chart of the process for selecting children to participate in the caries-progression analyses. The regional ethics committee approved the study 20110119 Daybook no. 2010/1956-31/4 and the children’s parents signed informed-consent forms. The study is registered at www.controlled-trials.com (ISRCTN35086887).

Table 1
Baseline characteristics of the participating children in the test and the reference groups (n = 801).
Variable Reference group n = 375 (%) Test group n = 426 (%)
Girls/boys 53/47 53/47
Immigrant a 87 88
Mothers’ education (<9 years) 28 27
Family income (<SEK b 20.000/month) 50 50
Tooth-brushing every day 54 46
Sweet drinks (>2/day) 15 13
Candy(>1/week) 14 11

a Other language than Swedish spoken at home.

b Swedish crowns.

Fig. 1
Flow chart of children in the progression analyses.

Intervention

The two parallel arms of the study comprised a test and a reference group. Children in the test group received a standard oral health program supplemented with biannual fluoride varnish applications (Duraphat ® , 22.6 mg of fluoride per ml, Colgate-Palmolive) between 1 and 3 years of age. The reference group, who received the standard oral health program including oral health information and a toothbrush and a tube of toothpaste (1000–1450 ppm fluoride), free of charge, at the annual examination.

Clinical examination

Trained examiners (n = 49) assessed dental caries using the ICDAS criteria, ranging from 0 to 6 . Interexaminer reliability was calculated and ranged between ĸ = 0.42 and 0.60 for ICDAS 0–6. With ICDAS 3 as cut-off for cavitation interexaminer reliability ranged between ĸ = 0.61 and 0.73. A more detailed description has been published earlier . None of the examiners had access to previous assessment protocols for the study subjects. They examined the teeth using optimal light, a dental mirror, and a probe with a ball-ended tip after removing excess saliva with a cotton roll. Before examination, the children’ teeth were cleaned with a toothbrush. Due to the young age of the children, it was difficult to consistently accomplish air drying for 5 s.

Statistical analysis

Statistical analyses used IBM SPSS software (version 22.0). For descriptive purposes, we present both crude and relative frequencies. To describe prevalence and surface-level distribution of cavitation, we defined the threshold for cavitation as an ICDAS score of 3 . Cross-referenced tables show caries progression. The chi-square test assessed differences in caries progression between the test and reference groups, with p < 0.05 set as the threshold for statistical significance.

To avoid compromising the results of the analysis of progression on buccal surfaces, we chose to exclude some surface values that seemed misclassified, specifically values that showed regression from ICDAS 3–6 to ICDAS 0. At 24 months, we excluded 0.6% of the surfaces and at 36 months, 5.1% of the surfaces. We tested the differences in excluded surface values between the test and the reference groups using kappa analyses and found no significant differences ( p = 0.30).

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Jun 17, 2018 | Posted by in General Dentistry | Comments Off on Impact of biannual treatment with fluoride varnish on tooth-surface-level caries progression in children aged 1–3 years

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