SEM and Microleakage Evaluation of 3 Flowable Composites as Sealants Without Using Bonding Agents

Resident: Cho

Author(s): Kwon et al.

Journal: Pediatric Dentistry

Year. Volume (number). Page #’s: 2005. 27. 48-53.

Major topic: flowable composite, sealant

Minor topic: microleakage, SEM

Type of Article: Scientific Article

Main Purpose: The aim of this study was to determine if 3 different flowable composites could be used as pit and fissure sealants without the use of bonding agents.

Overview of method of research:

The sealant material used in this study: Ultraseal XT Plus

The flowable composites used in this study: Filtek Flow, Tetric Flow, Charmfil Flow

SEM observations

Two extracted, erupted human permanent third molars were selected for each sealant material. The flattest surface was ground flat and polished. The tooth’s crown was sectioned in half mesiodistally through the flat ground surface. Each enamel surface was cleaned with pumice/water slurry, then rinsed, and dried. 35% phosphoric acid conditioning gel was applied to each surface for 30 seconds, then rinsed, and dried. A sealant material was applied to 1 of the 2 acid-etched surfaces for 20 seconds, then light cured for 40 seconds. The tooth section with the sealant applied was dissolved in 1 N HCl and the sealant was detached. For each SEM specimen, both the section of the etched enamel surface and the detached sealant from the other section were mounted together and examined.

Microleakage assessment

Fifty-four extracted human premolars previously stored were randomly divided into 3 groups:

Group 1 – Ultraseal XT Plus/Filtek Flow

Group 2 - Ultraseal XT Plus/Tetric Flow

Group 3 - Ultraseal XT Plus/Charmfil Flow

¼ round bur in high-speed handpiece was used to do enameloplasty of 1mm thickness. All of the teeth were prepared by the same operator. Pumice slurry was used to clean the tooth. The occlusal fissures were acid etched for 30 seconds using 35% phosphoric acid, rinsed, and dried. Flowable composite was applied to half of the prepared fissure using a dental explorer. Penetration time was 20 seconds, then the composite was light cured for 40 seconds. The filled sealant was then applied to the other half of the fissure using the same method and light cured for 40 seconds. The teeth were treated with 1% methylene blue dye. One person, who was blinded to the treatment groups, recorded the extent of dye penetration using the following scale:

0 – no dye penetration

1 – dye penetration restricted to the outer half of the sealant

2 – dye penetration to the inner half of the sealant

3 – dye penetration into the underlying fissure

Findings: The Ultraseal XT Plus showed significantly less microleakage than the 3 flowable composites. There was no statistical different in microleakage among the 3 flowable composites. No void was observed in any of the Ultraseal XT Plus groups. However, a void was found in 3 of the Filtek Flow specimens and 6 of the Tetric Flow and Charmfil Flow specimens.

Key points/Summary: Filled sealant is more effective in sealing mechanically prepared occlusal fissures compared to flowable composites. Special care is needed when applying flowable composites to occlusal fissures because of void formation.

Assessment of Article: Good article. Would be interesting to know how adding the bonding agent to the flowable composite groups would have affected the results of this study.