Sealants reduce caries in primary molars

The recent Cochrane review update on fissure sealants (Dental Elf- 8^th Apr 2013) recommended sealants to prevent or control caries in children and adolescents. However, the number of trials evaluating their effectiveness on primary molars, which are present in the mouth for around 10 years, is small. The aim of this study was to measure the caries preventive effect of sealants applied to occlusal surfaces of primary molars compared to fluoride varnish, and to assess the retention rate of sealants after 1 year.

Methods

First year kindergarten children (4-5yrs) were examined by an ICDAS trained and calibrated examiner. If the occlusal surface of the first or second molar or both in the upper or lower right quadrant had ICDAS caries codes 0–4, the quadrant was randomized for sealant or fluoride varnish intervention. Matching molars on the contralateral side of the mouth (in the same jaw) received the other intervention.

Sealant material used was light-cured ClinproTM (3M ESPE) and fluoride varnish DuraShield® (Sultan Healthcare) containing 5% sodium fluoride. Sealants and varnish were applied following the instructions of the manufacturers. The intervention was provided in the school premises in a mobile dental chair. All children received hands-on toothbrushing instructions and fluoride varnish application in both kindergartens 6 months before and 6 months after the intervention. A dentist blind to the interventions undertook follow up examinations at 1 year. The primary outcome was caries prevention at one year. Sealant retention was the secondary outcome

Results

106 children, 158 matched quadrants with 267 comparable pairs of molars were eligible.
Baseline caries experience (dmfs) was higher in boys (13.2 [SD 13.2]) than girls (6.9 [SD 100]. The majority (83.4%) of the occlusal surfaces were sound (ICDAS caries code 0).
The number of occlusal surfaces with ICDAS score of 0 at baseline and at 12months in shown in the table.

	Sealant. N (%)	Varnish. N (%)
Baseline (ICDAS =0)	223	223
12 months (ICDAS =0)	211 (94.6%)	188 (84.3%)

Varnished surfaces were significantly more likely to develop new caries lesions than the sealed ones in the first year. Odds ratio = 2.92; (95% CI = 1.82-4.71)
73% of sealants were completely retained, 15.1% partially retained.

Conclusions

The authors concluded:

Fissure sealants were superior to fluoride varnish applications in preventing development and progression of caries lesions in occlusal surfaces of primary molars over 1 year. Providing sealants on primary molars in addition to biannual fluoride varnish applications to the preschool children with a high caries risk can help reducing caries occurrence.

Comments

This well conducted trial demonstrates the effectiveness of sealant use in the primary dentition. However, it should be noted that all the children also received fluoride varnish 6 months before and after the trial intervention (sealant or varnish) and this needs to be taken into consideration. The authors also highlight that this is a split mouth study so there may be concerns about a carry over effect from the fluoride varnish use. Although the authors cite one study by Sköld-Larsson et al, which suggests that, this is not an issue, but that was conducted in older children.