Introduction

Primary prevention employs techniques and agents to forestall the onset of the disease and to arrest the disease process before treatment becomes necessary¹. Pit and fissures in newly erupted molars are considered as highly susceptible to caries, because fissures are less benefited by topical fluoride compared to smooth surface². Dental sealants have been shown to be effective in the prevention of pit and fissure caries³.

In the recent years, fluoride containing fissure sealants have been introduced, which enhance the caries preventive effect. The micromechanical retention for the sealant is produced by conditioning the enamel with acid prior to the application of the sealant⁴. A Glass Ionomer material specifically developed for fissure sealing (Fuji III) has been introduced, which has small particle size in order to facilitate its penetration into the fissures⁵. It has a strong bond to tooth structure without the need to etch the tooth surface and has been excellent biocompatibility⁶.

The key issue is that if the sealant is properly placed, it remains intact with complete retention so that the sealed surfaces are virtually impervious to decay³. The preventive properties of sealants are only gained and maintained as long as they remain completely intact and bonded in place⁷. The most commonly used method in evaluating the clinical performance of pit and fissure sealant is a visual tactile examination whereby the sealant is recorded as intact, partially lost and completely lost. Photometric and Scanning Electron Microscopy of tooth replica models also had been employed. These methods are useful aids in determining the extent and location of sealant coverage after a period of clinical use^8-9.

The aim of this study was to evaluate the retention of Fuji III Glass Ionomer and Helioseal – F (fluoride containing light cure resin) pit and fissure sealants using tooth replica technique at 6 months and 12 month intervals.

Material And Methods

Forty children in the age group of 6-10 years were selected for the study, who reported to the Department of Pedodontics and Preventive Dentistry. Informed consent of parents or guardians was obtained before the subjects were included in the study. The mandibular permanent first molars in 40 children were selected accordingly to following criteria:

1. The first permanent molars which were erupted within 4 years.

2. Completely erupted teeth with the well defined fissure system and were not carious.

3. The teeth with deep, irregular pits and fissures.

4. The teeth had not been restored previously.

A total of 80 mandibular first permanent molar was divided into two groups:

Group I: Fuji III glass Ionomer Sealant

Group II: Helioseal F pit and fissure sealant.

Prior to applying sealant, the teeth were cleaned with short bristle brush using pumice slurry. Then teeth were washed thoroughly with water spray. A sharp explorer tip was passed through all the pits and fissures to remove pumice (remaining if any). The teeth were washed and dried thoroughly. The rubber dam was then placed on the selected tooth to achieve proper isolation. Prior to sealant placement teeth were dried for 10 seconds with air spray.

In Group I, Fuji III glass ionomer sealant was mixed and applied according to manufacturer's instruction on the pits and fissures of mandibular first permanent molar with the help of the applicator provided in the kit. When glass ionomer cement lost its glossiness, Fuji varnish was applied. Then the teeth were checked for occlusion with articulating paper.

In Group II the pits and fissures of mandibular first permanent molar teeth were etched with 37% phosphoric acid for 15 seconds and then rinsed with water. The teeth were dried with water and oil free air spray to achieve a characteristic frosty white, chalky appearance of enamel. The Helioseal F sealant was directly applied with the disposable cannula on the pits and fissures of teeth. After waiting for approximately 15 seconds, the sealant was cured for 20 seconds, and the occlusion was checked using articulating paper.

The patients were instructed not to eat or drink anything for half an hour. They were recalled for assessment of sealant retention at intervals of 6 and 12 months. Then an elastomer impression (Heavy and Light body) was made, of each sealed occlusal surface using custom made acrylic trays with Reprosil (Polyviny siloxane) impression material at 6 and 12 month interval.

Later the tooth replicas were examined under stereomicroscope and graded according to following scoring system⁹ [Fig.1]

Figure 1

Figure 1 Schematic illustration of main grooves and fossae of occlusal surface of permanent mandibular first molar and the criteria used for scoring extension of the sealant from score A to score D. Solid lines: Sealant present, Dotted lines: Sealant absent.

Results

Out of 80 teeth assessed, 40 teeth were sealed with Fuji III glass ionomer sealant and 40 teeth with Helioseal-F fissure sealant. Of these 80 teeth, 78 teeth were available for an assessment after 6 months and 72 teeth were examined at 12 months.

The Inter-group comparison of retention at 6 month intervals [Table 1]

In Fuji Glass Ionomer Sealant (Group I), the 38 teeth were assessed out of 40 teeth. Out of the 38 teeth available for examination,15 (39.5%) teeth showed complete sealant retention (Score A), 8 (21.1%) teeth showed sealant loss from one or more grooves (Score B), 6 (15.8%) teeth showed sealant loss from grooves and one fossae (Score C) and 9 (23.6%) teeth showed complete loss of sealant (Score D).

In Helioseal F (Group II), out of the 40 teeth, 19 (47.5%) teeth showed complete sealant retention (Score A), 16 (40%) teeth showed sealant loss from one or more grooves (Score B), 4 (10%) teeth showed sealant loss from grooves and one fossae (Score C) and 1 (2.5%) tooth showed complete loss of sealant (Score D).

At the 6 month intervals the retention rate of helioseal-F (Group II) was significantly higher than the Fuji III glass ionomer sealant (Group I) (X2 =10.14, diff. 3, P<0.05).

Figure 2

TABLE – 1 INTER-GROUP COMPARISION OF RETENTION OF FUJI III GLASS IONOMER CEMENT AND HELIOSEAL-F SEALANT AT 6 MONTH INTERVAL:

The Inter-group comparison of retention at 12 month intervals [Table 2]

In Fuji III glass ionomer (Group I), the 34 teeth were assessed out of 40 teeth. Out of the 34 teeth available for examination, 6 (17.7%) teeth showed complete sealant retention (Score A), 5 (14.7%) teeth showed sealant loss from one or more grooves (Score B), 8 (23.5%) teeth showed sealant loss from grooves and one fossae (Score C) and 15 (44.1%) teeth showed complete loss of sealant (Score D).

In Helioseal F (Group II), out of the 40 teeth 38 teeth were assessed. Out of 38 teeth available for examination, 14 (36.9%) teeth showed complete sealant retention (Score A), 10 (26.3%) teeth showed sealant loss from one or more grooves (Score B), 10 (26.3%) teeth showed sealant loss from grooves and one fossae (Score C) and 4 (10.5%) tooth showed complete loss of sealant (Score D).

At 12- month intervals helioseal-F sealant showed a difference in the retention rate than that of glass ionomer sealant, which was statistically significant (X2 =11.15, diff. 3, P<0.05).

Figure 3

TABLE – 2 INTER-GROUP COMPARISION OF RETENTION OF FUJI III GLASS IONOMER CEMENT AND HELIOSEAL-F SEALANT AT 12 MONTHS INTERVAL

The Intra-group comparisons of retention in Fuji III and Helioseal-F pit and fissure sealant at 6 and 12 month intervals [Table 3 and fig 2]

Fuji III Glass Ionomer Sealant

Helioseal-F Sealant

The 40 teeth assessed at 6 month interval, and 38 teeth were assessed at 12 month interval. The complete retention (Score A) was observed in 19 (47.5%) teeth at 6 month interval and 14 (36.8%) teeth at 12 month interval. The extensive loss of sealant (Score D) seen in 1 (2.5%) tooth at 6 months and in 4 (10%) teeth at 12 months. The retention rate of helioseal-F sealant assessed at 6 and 12 months interval showed statistically insignificant results (X2 =6.64, diff. 3, P>0.05).

Figure 4

TABLE-3 INTRA-GROUP COMPARISION OF RETENTION OF FUJI III GLASS IONOMER CEMENT AND HELIOSEAL-F SEALANT AT 6 AND 12 MONTHS INTERVALS

Figure 5

Figure 2: COMPARISION OF RETENTION OF FUJI III GLASS IONOMER CEMENT AND HELIOSEAL-F SEALANT AT 6 AND 12 MONTH INTERVALS

Discussion

In this study 40 children between the age groups of 6 to 10 years were considered because the risk of caries attack is highest in the pit and fissure of teeth for the first few years after their eruption¹⁰.

Completely erupted permanent mandibular first molars were selected to standardize the procedure. These teeth were selected because they present a particular challenge in caries prevention as they have deep occlusal surface, and their posterior location compromises access for cleaning and removing debris¹¹. In this study, the occlusal surface and fissures of the teeth were cleaned with pumice slurry and short bristle brush to make sure that these areas were free of gross plaque and debris. The clinical study by M.F. Donnan and I.A. Ball¹² showed that prophylaxis of teeth with pumice prior to etching contributes to sealant retention.

The rubber dam if placed properly provides the best and the most controllable isolation. Eidelman et al¹³ applied sealant with the use of cotton rolls or rubber dam for isolation. After 24 months the teeth isolated with rubber dam isolation showed 96% of complete sealant retention where teeth isolated with cotton roll isolation showed 88% retention. Barja-Fidalgo et al¹⁴ also found that glass ionomer cement used as a sealant can provide some level of protection against dental caries in situations where isolation is not possible.

The caries preventive effect of glass ionomer sealant depends on both retention of sealant and the release of fluoride from the sealant¹⁵. Glass ionomer sealants are suggested to be simple in technique (no acid etching) and low in cost. In the present study the lower retention rate was obtained with the glass ionomer cement when compared with the resin based sealants. The reasons for the loss of the glass ionomer sealants could be due to inadequate adhesion of the cement to the enamel surface^16,9 and brittle nature of the sealant material⁶. The effect of fluoride after sealant loss also must be considered. However, Torppa-Saarinen and Sepp⁵ and Carey et al¹⁷ described that despite the material loss, there were remaining retained particles of the GIC sealant in the bottom of the occlusal fissures, keeping its preventive effect. Other clinical trials on GIC sealants support this suggestion as well, providing evidence for a clearly protective effect by GIC sealant, despite the poor retention rate^5,9,15,18-19.

Helioseal – F was used in the present study, which is resin based light cure fluoride releasing pit and fissure sealant. Helioseal F offers improved caries protective effect of the sealing by an effective combination of blocking the bacteria and fluoride deposit. De Craene et al²⁰ also chosen Helioseal for its direct and easy application with cannula tips. The tips can be bent to allow easy access to any site and is a very economical system without waste of material.

The tooth replica technique, which is used in this study has been shown to be sufficiently sensitive to discern minor differences in wear resistance among sealants^8,9. Gwinnett²¹ reported that polyvinyl siloxane impression material can accurately reproduce the relationship between restoration and tissue.

In the present study, Helioseal- F sealant had a better retention rate than Glass ionomer sealant and this result was similar to the previous studies done^{22,23,10,24,9,25}. Forss H and colleagues¹⁰ compared the retention of glass ionomer fuji III and resin based light cured fissure sealants. After two years, 26% of the glass ionomer sealant and 82% of resin based sealant were totally present. In another study, Forss H. and Halme E²² evaluated the retention and caries preventive efficacy of glass ionomer (Fuji IIIGIC) after 6 to7 years, 10% of the GIC and 45% of the Delton sealant were totally present.

The similar results also found comparing the LCRB and RMGIC sealants, the retention rate of LCRB sealants was markedly higher than that of RMGIC sealants between the baseline and 6, 12,18,24,30 and 36-month intervals. The preventive effect of remaining glass ionomer particles is hardly comparable to the caries-preventive effect of LCRB sealants. Retention of the sealant, providing a leak-proof diffusion barrier, seems to be of greater importance²⁶. Yildiz et al²⁷ showed less retention rate than the concise white sealant and caries incidence was less in Helioseal – F. Rock W.P²⁸ reported retention of filled sealants to be lesser than that for unfilled sealants.

A. Carlsson, M. Petersson and S. Twetman² suggested that Helioseal – F fluoride containing fissure sealant, could be used satisfactory for caries prevention in children. Koch M.J et al⁴ and Vrbic V²⁹ stated that Heliseal – F sealant showed a very good retention rate after a 12 month interval. The Fuji triage showed significantly higher cumulative fluoride releasing pattern compared to resin based fissure sealant because of their less hydrophilic matrix characteristics^30,18. Markovic D.L, Petrovic B.B, Peric T.O³¹ confirm that glass ionomers are not very resistant to external agents and in low pH environments they are undergoing noticeable destruction. On the other hand, destruction of the material surface is followed by extensive fluoride release necessary to resist the caries attack.

Conclusion

The following conclusions were drawn from this study:

1. Helioseal – F pit and fissure sealant showed 47.5% complete retention at 6 month interval.

2. Fuji III glass ionomer sealant showed 39.5% complete retention at 6 month interval and 17.6% at 12 month interval.

3. Helioseal-F pit and fissure sealant showed a higher retention rate than the Fuji III glass ionomer sealant.