📄 medicine

Bond Strength of Three Ion-Releasing Restorative Materials to Primary Dentin Following Silver Fluoride Pretreatment: An In Vitro Study

This in vitro study found that while the alkasite material Cention Forte generally exhibited superior shear bond strength to primary dentin compared to glass ionomer cements, silver fluoride pretreatment equalized the performance of all three materials and slightly reduced Cention Forte's bond strength, with aging having a minimal overall effect.

Original authors: Zeynep Keleş Tepeli, Zülfikar Zahit Çiftçi, Nurgül Çetin Tuncer

Published 2026-07-08

📖 4 min read☕ Coffee break read

CC BY 4.0

Original authors: Zeynep Keleş Tepeli, Zülfikar Zahit Çiftçi, Nurgül Çetin Tuncer

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine your child's baby teeth are like old, slightly worn-out wooden floors. Sometimes, these floors get damaged by "cavities" (rot). To fix them, dentists used to have to sand down huge chunks of the floor, which was scary and painful for kids.

Now, there's a gentler way called SMART (Silver-Modified Atraumatic Restorative Treatment). It's like putting a patch on the floor without sanding it down too much. But here's the tricky part: before putting the patch on, the dentist might paint the damaged spot with a special silver liquid (Silver Fluoride) to kill the rot.

This study asked a simple question: If we paint the floor with this silver liquid first, which type of "patch" material sticks the best?

The researchers tested three different patch materials on baby teeth:

Fuji IX: A thick, traditional glass cement (like a heavy-duty concrete patch).
Fuji II LC: A glass cement mixed with a little resin that hardens under a blue light (like a patch that needs a UV lamp to set).
Cention Forte: A newer, "alkasite" material (think of this as a high-tech, super-strong polymer patch).

They tested these patches in three different scenarios:

Scenario A: On a perfectly healthy floor (Sound Dentin).
Scenario B: On a floor that was artificially rotted (Demineralized Dentin).
Scenario C: On a rotted floor that was first painted with the silver liquid (Silver Fluoride Pretreatment).

They also simulated years of chewing and temperature changes (hot coffee, cold ice cream) by running the teeth through a "thermal cycling" machine, which is like a stress-test gym for the patches.

What They Found

1. The "Super Patch" (Cention Forte)
On healthy teeth and even on rotted teeth without the silver paint, Cention Forte was the clear winner. It stuck about three times better than the other two materials. It was like using a super-strong industrial glue compared to regular glue.

2. The Silver Paint Effect
When they painted the rotted teeth with the silver liquid first, things got interesting.

The silver paint acted like a barrier. It made it harder for any patch to stick.
Cention Forte still held on the best overall, but its grip dropped significantly because of the silver paint.
Fuji IX and Fuji II LC didn't change much; they were already struggling, and the silver paint didn't make them much worse (or better).
Crucially: Once the silver paint was on, the difference between the three materials disappeared. They all stuck about equally poorly.

3. The "Aging" Test
They checked if the patches would fall off after years of simulated chewing.

For healthy teeth and simple rotted teeth, time didn't really matter; the patches stayed put.
However, on the silver-painted teeth, time was a problem. The Cention Forte and Fuji II LC patches got weaker after the stress test. The Fuji IX patch actually got slightly stronger (or stayed the same), but it was still the weakest overall.

The Bottom Line

Think of it like this:

If you are fixing a healthy or lightly damaged tooth, Cention Forte is the strongest glue you can use.
If you use the silver liquid (to stop the rot), it acts like a layer of wax on the floor. It makes it much harder for any glue to stick.
Even though the silver liquid makes Cention Forte weaker, it is still the best choice overall, even if it's not as strong as it was before.
The other two materials (Fuji IX and Fuji II LC) are decent, but they don't stick as well as Cention Forte, and the silver liquid doesn't help them stick better.

In short: The new "super patch" (Cention Forte) is the strongest, but if you use the silver medicine first, it loses some of its superpowers. The silver medicine also makes the other patches perform about the same as each other, which is generally lower than the super patch.

Technical Summary: Bond Strength of Three Ion-Releasing Restorative Materials to Primary Dentin Following Silver Fluoride Pretreatment

Problem Statement
Dental caries in primary teeth presents significant challenges, particularly for pediatric patients with behavioral difficulties or special healthcare needs. While traditional restorative techniques often require extensive cavity preparation and can lead to pulp exposure, minimally invasive approaches such as Atraumatic Restorative Treatment (ART) and Silver-Modified Atraumatic Restorative Treatment (SMART) have emerged as viable alternatives. These techniques rely heavily on the adhesion of fluoride-releasing restorative materials to dentin substrates that may be sound, carious, or treated with Silver Diamine Fluoride (SDF) or Silver Fluoride (SF). However, the long-term stability and bond strength of these materials under varying clinical conditions—specifically on demineralized dentin treated with SF and subjected to aging—remain insufficiently understood. This study addresses the need to evaluate and compare the shear bond strength (SBS) of three distinct ion-releasing materials under these specific conditions.

Methodology
This in vitro study utilized 180 extracted primary second molars, which were categorized into sound dentin, artificially demineralized dentin, and artificially demineralized dentin treated with Silver Fluoride (SF). The teeth were divided into 18 groups based on three restorative materials and three dentin surface conditions, with further subdivision for thermal cycling.

Materials Tested:
1. Fuji IX (FIX): High-viscosity glass ionomer cement (HVGIC).
2. Fuji II LC (FII): Resin-modified glass ionomer cement (RMGIC).
3. Cention Forte (CF): An alkasite material.
Experimental Protocol:
- Demineralization: Artificial carious lesions were induced using a pH-cycling protocol (14 days) involving alternating immersion in demineralizing and remineralizing solutions.
- SF Pretreatment: Specific groups received a one-minute application of SF solution (Riva Star Aqua) on demineralized dentin.
- Restoration: Materials were applied using 4 mm internal diameter molds. Cention Forte required a manufacturer's primer; Fuji II LC was light-cured; Fuji IX was chemically cured.
- Aging: Half of the specimens underwent 500 thermal cycles (5°C to 55°C) to simulate aging, while the other half remained non-thermocycled.
- Testing: Shear bond strength was measured in megapascals (MPa) using a universal testing machine. Fracture modes were analyzed via stereomicroscopy, and surface morphology was examined using Scanning Electron Microscopy (SEM).

Key Results

Material Performance on Sound and Carious Dentin: Cention Forte (CF) demonstrated significantly higher shear bond strength compared to both Fuji IX (FIX) and Fuji II LC (FII) on both sound and artificially carious dentin surfaces ( $p < 0.05$ ). No significant difference was observed between FIX and FII on these surfaces.
Effect of Silver Fluoride (SF) Pretreatment: On SF-treated demineralized dentin, the bond strengths of all three materials were lower compared to their performance on untreated dentin. Notably, the significant differences observed between materials on sound and carious dentin disappeared on SF-treated dentin ( $p > 0.05$ ), indicating that SF application equalized the bond performance among the tested materials, albeit at lower overall values.
Impact of Aging (Thermal Cycling):
- On sound and carious dentin, aging had a limited overall effect on bond strength across the materials.
- On SF-treated dentin, aging significantly reduced the bond strength of FII and CF ( $p < 0.05$ ), whereas FIX remained unaffected by thermal cycling.
- Specifically, for CF, the reduction in bond strength on SF-treated dentin after aging was statistically significant compared to non-thermocycled groups.
Fracture Analysis: Adhesive and mixed failures were the predominant fracture types across all groups, with no significant differences in failure modes among the groups.

Significance and Claims
The authors conclude that the bond performance of fluoride-releasing restorative materials is heavily influenced by the dentin substrate and the application of SF pretreatment. While Cention Forte exhibited superior bond strength under most conditions (sound and carious dentin), its performance was notably compromised by SF pretreatment and subsequent aging.

The study suggests that clinicians should exercise caution when selecting restorative materials for SMART protocols. Although Cention Forte generally offers the highest bond strength, the application of SF significantly reduces its adhesion to demineralized dentin. Conversely, while Fuji IX and Fuji II LC showed lower initial bond strengths, they maintained more consistent performance on SF-treated dentin, with Fuji IX showing resilience to aging effects in this specific context. The findings aim to guide material selection for ART and SMART techniques, highlighting that while SF aids in caries arrest, it introduces interfacial challenges that alter the bonding dynamics of modern restorative materials.

Limitations
The authors acknowledge limitations including potential variations in dentin depth and characteristics that could not be fully standardized, the use of a limited number of thermal cycles (500) which only partially simulates long-term aging, and the inability to blind the operator due to visible color differences among the materials.

What They Found

The Bottom Line

More like this