Comparison of  clinical effectiveness of conventional and self-etch sealant: a split mouth randomized controlled trial

Introduction

Occlusal caries still continue to be the most common form of decay in the permanent dentition due to the presence of deep retentive pits and fissures. Prevention of occlusal caries is a challenge but can be controlled through non-operative measures when implemented early.^1,2 American Academy of Pediatric Dentistry and Cochrane recommend pit-and-fissure sealants application on newly erupted posterior teeth so as to reduce the incidence of pit and fissure caries.^3,4 Sealant retention is one of the crucial factors for it to be effective and this can be achieved by various factors.⁵

Etching enamel with phosphoric acid is a conventional and standard technique practiced to improve retention.⁶ Unfortunately, salivary contamination following etching, decreases the adhesion of the sealant due to the formation of a tenacious surface coating, thus requiring the etching procedure to be repeated. Considering the compliance of the young child, a sealant that provides good retention and having a short procedure of application would be ideal.⁶

Self-etching sealants are products that have a one-step application with fluoride releasing properties. They can thus prove to be beneficial compared to the other resin sealants especially in pediatric practices.² There have been many in-vitro evaluation studies^6,7 conducted comparing the self-etch sealant with conventional acid etch sealants. The present in-vivo study was thus designed with the focus to clinically evaluate the sealing ability and retention of the self-etching sealant compared to the conventional resin sealant.

The objective of this study was to evaluate the retention of the sealant material and marginal enamel changes at 3, 6 and 12-months following sealant placement. The null hypothesis was that there would be no difference in the retention and marginal enamel structure between the self-etch and conventional acid-etch sealant at three, six and 12-month follow up.

Methods

Results

50 children were screened initially and 38 (76 teeth) of them were selected based on the inclusion criteria.²⁰ Out of them 3 children failed to report for sealant placement and did not respond to our calls as depicted in the flow chart (Figure 1).

Figure 1. CONSORT flow chart.

The final study samples consisted of 15 males and 20 females with the mean age of 8.5 years.

Teeth with partial/complete loss of sealants were repaired and were then subsequently dropped from the study. Their scores, however, were carried forward into the successive follow up appointments.

Complete retention of sealants at the 12 month evaluation period was 34.3% in group 1 and 22.9% in group 2 samples, whereas it was 11.4% in group 1 and 20% in group 2. Partial loss of sealants were more common in both the groups than complete loss as observed during all the three evaluation periods. Most of the retention failure was seen in the first evaluation period. Intergroup comparison of Simonsen’s Score for sealant retention between group 1 and 2 at follow-up was done using chi-square test and was found to be non-significant (p=0.135) (Table 1).

Overall, 85.7% of the group 1 and 82.9% of the group 2 samples exhibited good marginal integrity with no clinical changes in the enamel around the margins. Few of the teeth in both the groups exhibited discoloration and roughness but this was not statistically significant (p=0.5). In both the groups all the failures were seen by the first evaluation period at 3 months (Table 2).

Discussion

Many techniques were used to improve the retention of the sealants apart from the conventional acid etch. It included application of bonding agent on the etched surface and use of self etch adhesive liners before the placement of resin sealants.⁸ But with all this, the technique became more lengthier.^13,14 With the introduction of self etch sealants and steps in application reduced, it’s been very convenient and clinically easy to apply compared to the acid etch sealants.⁶

In an in vitro study by Garg et al,⁶ the sealing ability and microleakage of Preventseal and Clinpro™ were evaluated. They documented that the retention and marginal integrity of the self-etching sealant, Preventseal was found to be similar to that of the conventional acid etch sealant.

Based on the above information, we designed our in-vivo study to clinically compare the retention and marginal integrity following the placement of Preventseal and Clinpro™ sealants. Clinpro™ Sealant is a light-cured, fluoride releasing pit and fissure sealant with a color-changing feature. It is pink when applied to the tooth surface, and changes to an opaque off-white color when exposed to light. It contains 2, 2-bis[4-(2-hydroxy-3 methacryloxypropoxy)phenyl] propane, tri (ethylene glycol) dimethacrylate, a light cure initiator system based on camphorquinone, a tertiary amine and an iodonium salt.¹¹ Preventseal is a self-etched, light cured, fluoride releasing pit and fissure sealant. As the name suggests it requires no etching, rinsing or drying. It contains Bis-GMA, and triethyleneglycoldimethacrylate - 2-Hydroxyethylmethacrylate.¹²

A split mouth design was used to reduce the inter-subject variability. It also reduced the sample size and improved our statistical efficiency as each patient served as his/her own control and created a relatively smooth follow-up. Unfortunately, each design has its own merits and demerits. The attrition of even one patient in this trial amounted to loss of data in all the fields and was hence considered when the sample size was calculated.¹⁵

Other common drawbacks of split mouth design are carry-across effect and restriction in selection bias. Carry across effect is the effect of one material over the other as both are present in the same mouth.¹⁶ But in the present study as we analyzed the retention and marginal seal, risk of cross over effect was nil. Selection bias was minimized through sample selection based on inclusion criteria as mentioned in material and method.

Coin toss is a simple method of randomization and ensures that the teeth are equally allocated to both the groups.¹⁷ The outcome of the coin toss is determined by certain factors such as the speed of the flip, method of catching it back, the weight of the coin and individual variations.¹⁸ There is a possibility that this may influence the outcome. In the present study we have used the same coin and tossing was done by the same operator who was not the part of the clinical trial thus reducing the manipulation risk.

Further, this study was double blinded as both the data analyst and the participants were unaware of the type of sealant applied.

This study’s inclusion criteria were drafted keeping the recommendations from AAPD and the British Society of Pediatric Dentistry in mind.^3,19 Based on these guidelines, sealants should be applied to the child’s first permanent molar between the ages of 7–10 years.¹⁷ This ensures that the newly erupted teeth are protected from demineralization. Additionally, only children with fully erupted first permanent molars were included, to reduce the risk of bias caused by moisture contamination during sealant application.²⁰

All scientific measurements come with some degree of imprecision, hence the evaluation criteria was selected that minimized this to possible extent.

Although Clinpro™ exhibited better retention, the results were non-significant. Thus, it can be concluded that the self-etch sealant, Preventseal is as effective as Clinpro™ Sealant with adequate retention and marginal integrity and the null hypothesis is accepted.

A potential trial limitation is that since the two materials have different color, the operator and the clinical evaluator could not be blinded, which could have led to potential bias. To minimize this, the data analyst was blinded to the group allocation.

Conclusion

Sealants with less procedural steps and those that provides adequate retention are ideal to be used in children. Thus, Preventseal has proven to be effective and efficient having good retentive ability and marginal integrity when used as a sealant in permanent molars.

Data availability