In vitro remineralization of adjacent interproximal enamel carious lesions in primary molars using a bioactive bulk-fill composite

Abstract

Background: Surface remineralization is recommended for the management of active non-cavitated interproximal carious lesions in primary teeth. According to the American Academy of Pediatric Dentistry, a recently recognized category of materials called bioactive restorative materials can be used for remineralization. This study aimed to evaluate the release of fluoride (F), calcium (Ca) and phosphate (P) ions from Predicta® Bioactive Bulk-fill composite compared with EQUIA Forte® and Filtek™ Z350 and to determine the remineralization effect of these 3 restorative materials on adjacent initial interproximal enamel carious lesions.

Methods: The release of F, Ca and P ions from 3 groups ((n = 10/group) (Group 1- Predicta®, Group 2- EQUIA Forte® and Group 3- Filtek™ Z350)) was determined at 1st, 4th, 7th and 14th days. After creating artificial carious lesions, human enamel samples were randomly assigned into 3 groups (n = 13/group) which were placed in contact with occluso-proximal restorative materials and exposed to a 14-day pH cycling period. Surface microhardness was determined using a Knoop microhardness assay at baseline, after artificial carious lesions formation and after pH cycling. The difference in the percentage of surface microhardness recovery (%SMHR) among groups was compared. Mineral deposition was analyzed with energy-dispersive x-ray spectroscopy (EDS) and the enamel surface morphology was evaluated with scanning electron microscopy (SEM). Kruskal-Wallis's test with Dunn's post hoc test and one-way ANOVA with Tukey's post hoc test were used for data analysis.

Results: EQUIA Forte® released the highest cumulative amount of F and P ions, followed by Predicta® and Filtek™ Z350. Predicta® released higher amount of Ca ions than EQUIA Forte® and Filtek™ Z350. Predicta® demonstrated the highest %SMHR, followed by EQUIA Forte® and Filtek™ Z350. There was a significant difference in the %SMHR between Predicta® and Filtek™ Z350 (p < 0.05). However, EQUIA Forte® demonstrated the highest fluoride content, followed by Predicta® and Filtek™ Z350. The SEM images of EQUIA Forte® and Predicta® revealed the greater mineral deposition.

Conclusion: Predicta® demonstrated a marked increase in surface microhardness and fluoride content of adjacent initial interproximal enamel carious lesions in primary molars compared with Filtek™ Z350. Predicta® is an alternative restorative material to remineralize adjacent initial interproximal enamel carious lesions in primary molars, especially in high-risk caries patients.

Keywords: EDS-SEM; Initial interproximal carious lesions; Predicta® bioactive bulk-fill composite; Remineralization; Surface microhardness.

Fig. 1

Schematic presentation of evaluation of ions release

Fig. 2

Diagrammatic presentation to simulate natural contact point

Fig. 3

Schematic presentation of SMH measurement and EDS-SEM analysis

Fig. 4

Comparison of the mean surface microhardness at baseline, after artificial carious lesions formation and after pH cycling among the 3 groups. ^* Comparison of the mean surface microhardness between Predicta® and Filtek™ Z350 after pH cycling (p = 0.002). One-way ANOVA with Tukey’s post hoc test

Fig. 5

Mean of the percentage of surface microhardness recovery among 3 groups. ^* Significant difference between groups is indicated by an asterisk (*) using Dunn’s test of multiple comparison (p < 0.05)

Fig. 6

SEM images of the initial enamel caries after in contact with the restorative materials (Group 1- Predicta®, Group 2- EQUIA Forte®, and Group 3- Filtek™ Z350 at × 5000 and × 10,000 magnifications)