Effect of saliva contamination and re-etching time on the shear bond strength of a pit and fissure sealant

Comparative evaluation of retention and cariostatic effect of glass ionomer, hydrophobic & hydrophilic resin-based sealants: a systematic review and meta-analysis

OBJECTIVE

To compare the effectiveness of hydrophilic resin-based versus hydrophobic resin-based and glass-ionomer pit and fissure sealants.

METHODS

The review was registered with Joanna Briggs Institute and followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, Google Scholar, Virtual Health Library, and Cochrane Central Register of Controlled Trials were searched from 2009-2019 using appropriate keywords. We included randomized controlled trials and randomized split-mouth trials conducted among 6-13-year-old children. The quality of included trials was assessed using modified Jadad criteria and risk of bias using guidelines specified by Cochrane. GRADE (Grading of Recommendations Assessment, Development, and Evaluation) guidelines were used to assess the overall quality of studies. We used the random-effects model for meta-analysis. Relative risk (RR) and confidence intervals (CI) were calculated & heterogeneity was tested using I² statistic.

RESULTS

Six randomized clinical trials and five split-mouth trials met the inclusion criteria. The outlier augmenting the heterogeneity was omitted. Based on very-low to low-quality evidence, loss of hydrophilic resin-based sealants was less likely as compared to glass-ionomer fissure sealants (4 trials at 6 months; RR = 0.59; CI = 0.40-0.86), while it was similar or slightly lower than hydrophobic resin-based sealants (6 trials at 6 months; RR = 0.96; CI = 0.89-1.03); (6 trials at 12 months; RR = 0.79; CI = 0.70-0.89); (2 trials at 18 months; RR = 0.77; CI = 0.48-0.25).

CONCLUSION

This study revealed that retention of hydrophilic resin-based sealants is better than glass ionomer sealants but similar to hydrophobic resin-based sealants. However, higher-quality evidence is necessary to underpin the outcomes.

Shear Bond Strength and Microleakage of Pit and Fissure Sealants Placed after Saliva-Contaminated Etched Enamel

Saliva contamination of etched enamel before sealant application is the most common reason for failure of fissure sealants, thus affecting the effect of caries prevention. This study aimed to evaluate the shear bond strength (SBS) and microleakage of resin-based fissure sealant on saliva-contaminated etched enamel after rinsing, re-etching, and applying universal adhesive. Fifty human third molars were sectioned into 2 parts and embedded in acrylic resin to obtained 100 samples. The samples were randomly assigned to 5 groups: 1, etching; 2, etching + contamination; 3, etching + contamination + rinsing; 4, etching + contamination+ re-etching; 5, etching + contamination + universal adhesive. Each group was divided into 2 subgroups: 24 h storage and 5000× thermocycling. After measuring SBS, failure mode was analyzed. In an additional 15 teeth, microleakage was tested using dye penetration method. Three more teeth were used for scanning electron microscope (SEM) observation of the enamel surface morphology in each group. The adhesive group had significantly higher mean SBS after 24 h storage, while the re-etching group were better after 5000× thermocycling. The etching, etching+ contamination+ re-etching, and etching+ contamination+ universal adhesive groups showed the least microleakage. The SEM reveals considerable variations in the enamel surface appearance within groups. Re-etching or applying universal adhesive in saliva-contaminated etched enamel before sealant can achieve satisfactory results. Considering the less operative steps and the shorter chair time, applying universal adhesive is more recommended for a pediatric patient if saliva-contamination happened before sealant application.

[Evaluation of the effect of sodium hypochlorite gel on composite bonding strength to enamel of primary teeth after salivary contamination: in vitro study]

OBJECTIVE

The study investigated the effect of 2%s odium hypochlorite gel application after post-etching salivary contamination on composite bonding strength to primary teeth enamel.

MATERIAL AND METHODS

The sample consisted of 79 primary human teeth that were extracted no more than one month ago. The sample was randomly divided into four groups: (1) the control group (A) comprised 10 primary teeth, and composites were applied in the traditional manner without any salivary contamination; (2) the second group (B) consisted of 23 primary teeth in which salivary contamination was conducted after etching followed by re-etching and follow-up; (3) the third group (C) comprised 23 primary teeth in which saliva contamination was done after etching followed by washing, drying, and follow-up; and (4) the fourth group (D) comprised 23 primary teeth, in which salivary contamination was conducted after etching followed by application of sodium hypochlorite gel and follow-up. The samples were tested using the Testometric Tensile Strength Device (Testometric M350-10 kN, Testometric Ltd., UK) to measure the composite bonding strength to enamel of primary teeth.

RESULTS

The arithmetic mean strength values in the research sample were ordered as followed: (A=13.39 MPa) > (D=11.82 MPa) > (C=8.07 MPa) > (B=6.15 MPa). The application of sodium hypochlorite gel after salivary contamination significantly improved the composite bonding strength to primary teeth enamel when compared with re-etching or only washing and drying.

CONCLUSION

15 s exposition of sodium hypochlorite gel with subsequent rinse and drying is recommended in case of saliva contamination of etched primary tooth enamel surface.

Bioactive glass ceramic can improve the bond strength of sealant/enamel?

AIM

Evaluate the influence of enamel pre-treatment using Biosilicate, associated or not to other treatments; on the bond strength (BS) of pit-and-fissure sealant, with or without saliva contamination.

METHODS

Ninety slices (4 mm × 4 mm) were obtained from 30 bovine incisors. Each slice was embedded in acrylic resin with their buccal surface exposed and polished to obtain a flat enamel surface. Half of them were contaminated with human saliva. All specimens were randomly divided into five groups (n = 9) according to the surface pre-treatment tested: acid etching (AE); AE + Biosilicate (B); AE + B + total-etch adhesive (Ad); Biosilicate; control (no treatment). Then, a 1 mm layer of sealant (Clinpro XT Varnish, 3M ESPE) was applied; and to provide support, a composite resin (Opallis, FGM) block was built up over it. Samples were thermocycled (500 cycles/5-55 °C) and sectioned obtaining sticks (1 × 1 × 10 mm) for microtensile BS testing (0.5 mm/min). Data were analysed with two-way ANOVA, Bonferroni test, p < 0.05. Failure patterns were evaluated using a stereomicroscope.

RESULTS

There was no difference among contaminated and non-contaminated groups, and between non-contaminated groups (p > 0.05). When contaminated, AE + B + Ad Group showed the highest BS values, differing (p < 0.05) from B Group and Control; similar between them (p > 0.05). Cohesive fractures were found in AE + B + Ad Group, submitted or not to contamination.

CONCLUSIONS

Since a surface pre-treatment was used, whether Biosilicate was applied or not, the sealant/enamel BS was the same in saliva-contaminated or non-contaminated enamel.