Adhesion of three types of fissure sealant in saliva-contaminated and noncontaminated conditions: an in vitro study

A scoping review of the influence of clinical contaminants on bond strength in direct adhesive restorative procedures

OBJECTIVE

Clinical contamination during direct adhesive restorative procedures can affect various adhesive interfaces differently and contribute to bulk failure of the restorations. This review aims to summarise the current knowledge on the influence of a variety of clinical contaminants on the bond strength at various adhesive interfaces during adhesive restorative procedures and identify gaps in the literature for future research.

DATA AND SOURCES

An electronic database search was performed in PubMed and EMBASE to identify articles that investigated the influence of contaminants on direct restorative bonding procedures. A data-charting form was developed by two researchers to capture the key characteristics of each eligible study.

STUDY SELECTION

The initial search yielded 1,428 articles. Fifty-seven articles published between 1 Jan 2007 and 25 Oct 2023 were included in the final review. Thirty-three of the articles examined the influence of saliva contamination, twelve articles examined the influence of blood contamination, and twenty-five articles examined the influence of other contaminants.

CONCLUSION

Saliva contamination exerted less influence on the decrease in bond strength when self-etch systems were used, compared to when etch-and-rinse systems were used. Blood contamination adversely affected the bond strength at the interface between resin composite and dentine, and resin composite and resin-modified glass ionomer cement. Treating contaminated surfaces with water spray for 10-30 s followed by air drying could be effective in recovering bond strength following saliva and blood contamination.

CLINICAL SIGNIFICANCE

This scoping review provides a valuable overview of the range of potential clinical contaminants that can influence the bond strength between different interfaces in direct adhesive restorative procedures. Additionally, it identifies potential decontamination protocols that can be followed to restore and enhance bond strength.

Micro-tensile bond strength of two pit and fissure sealants to intact enamel

Background

Sealing dental pits and fissures with resin-based sealants effectively prevents occlusal dental caries. The effectiveness of resin-based pit and fissure sealants relies on maintaining a strong bond between the sealant and the enamel.

Objective

This in-vitro study compared the micro-tensile bond strength (μTBS) of a conventional resin-based sealant (Clinpro™) and a hydrophilic resin-based sealant (Embrace™ WetBond™) when applied to intact, aprismatic human enamel.

Methods

Forty extracted permanent premolar and molar teeth were divided into two groups and paired by tightly approximating two buccal surfaces to create an artificial enamel groove (fissure). Fissure sealants (Clinpro™ and Embrace™ WetBond™) were applied to the artificial enamel 'grooves' in each group. The specimens were then cut into beams with a cross-sectional area of 1 mm2 and tested for the micro-tensile bond strength (μTBS). Fractured surfaces of samples were examined under a conventional microscope to identify the failure modes. Two specimens from each group were prepared and observed under a scanning electron microscope (SEM). Mann-Whitney U and Fischer-Freeman-Holton exact tests were used to test the statistical differences between the fissure sealants.

Results

The μTBS mean ± SD for Clinpro™ was 16.43 ± 7.08, and 10.57 ± 6.64 for Embrace™ WetBond™. There was a statistically significant difference in μTBS between Embrace™ WetBond™ and Clinpro™ (p < 0.001). There was no association between fissure sealant and failure modes (p = 0.922).

Conclusion

Clinpro™ showed higher μTBS to enamel than Embrace™ WetBond™. Further studies are needed to conclude the clinical effectiveness of these sealants.

A concise review of dental sealants in caries management

This concise review provides an update of the use of dental sealants. Dental sealants protect a tooth from caries development by providing a physical barrier to microorganism colonisation and creating a favorable environment for patients to clean. Some sealants release fluoride ions to promote remineralization. Dental sealants can be applied on pits and fissures of primary and permanent teeth to prevent and arrest early enamel caries. They are effective in caries prevention. The preventive fraction of resin sealant is up to 61% after 5 years. Dental sealants can be classified as resin, glass ionomer and hybrid (compomer or giomer) according to the material. Recent studies from 2012 to 2022 showed resin sealant has a high retention rate of up to 80% after 2 years, whereas glass ionomer sealants is 44%. Chemical etching with 37% phosphoric acid is the standard of care, whereas laser or air-abrasion cannot does not increase the sealant retention rate. Moist control is critical and studies found the use of rubber dam and cotton rolls had similar success for sealant retention. The longevity of dental sealant is also associated with clinical operative factors, including approaches of moisture control, enamel pretreatment, selection of dental adhesive, and time of acid etching.

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.