Vitamin C and Plant Compounds Boost the Grip of Dental Restorations
Simple acids may improve the strength and longevity of ceramic dental posts
Restoring a damaged tooth after root canal treatment can be tricky—especially when large parts of the tooth are missing. Dentists often rely on post-and-core systems, tiny internal supports that anchor a crown securely inside the root canal. A new study published in BMC Oral Health suggests that using natural acids such as ascorbic acid (vitamin C) and tannic acid can significantly improve the bond between tooth dentin and a new generation of ceramic post materials.
Why the bond matters
Endodontically treated teeth often lose much of their original structure, and the stability of any restoration depends on how strongly the post adheres to the tooth’s inner dentin. If that bond fails, the entire crown can loosen or detach. Traditionally, dentists have used a conditioning agent called EDTA to clean and prepare dentin before cementing posts, but researchers have long looked for gentler and more effective alternatives.
At the same time, advances in materials science have led to the development of polymer-infiltrated ceramic network (PICN) materials. These ceramics combine the hardness of glass with the flexibility of polymers, making them strong yet less brittle—ideal for customized posts fabricated with CAD/CAM (computer-aided design and manufacturing).
Testing acids and sealers
The research team, led by Ahmed E. Farghal and Mohammed Ahmed Alghauli at Taibah University (Saudi Arabia), investigated how different root canal sealers and dentin conditioning solutions affect the pull-out strength—the force required to detach—a customized PICN post-and-core.
They treated 80 extracted premolars and divided them into two main groups based on the sealer used:
a resin-based sealer (AH Plus), and
a calcium silicate–based “bioceramic” sealer (Bio-C Sealer).
Each group was further split into four subgroups based on the surface pretreatment:
No conditioning (control),
17% EDTA,
10% tannic acid, and
10% ascorbic acid.
After preparing, cementing, and curing the posts, the team measured how much force it took to pull them out.
What they found
Both the sealer type and the conditioning solution significantly influenced retention strength.
Teeth treated with ascorbic acid showed the highest pull-out strength (around 233 N), followed closely by tannic acid.
The EDTA group performed better than the control but not as well as the natural acids.
Posts sealed with calcium silicate–based materials generally held stronger than those with resin-based sealers.
Microscopic analysis showed that most failures occurred as mixed adhesive–cohesive types, suggesting strong bonding at multiple layers between dentin, cement, and ceramic.
Why vitamin C and tannic acid work
According to the authors, ascorbic acid helps by neutralizing the oxidative effects of cleaning agents such as sodium hypochlorite and improving the polymerization of resin cements. Tannic acid, a plant-derived polyphenol, promotes collagen cross-linking and prevents dentin degradation—both crucial for long-term adhesion.
These findings echo previous laboratory studies showing that mild natural acids can improve bond strength compared with traditional chemical conditioners.
The bigger picture
Although the experiment was conducted in the lab and did not include aging or real-world wear testing, the results suggest promising clinical benefits. Using 10% ascorbic or tannic acid to prepare dentin could make restorations more reliable—helping crowns stay put longer after root canal therapy.
Future studies will need to confirm these effects under realistic conditions and explore different combinations of ceramics and adhesives. Still, the message is clear: simple, biocompatible agents like vitamin C may have an unexpectedly powerful role in modern restorative dentistry.
Reference:
Farghal A.E., Alghauli M.A., Ellayeh M., Alqutaibi A.Y., Alzemei M., & Saker S. (2025). Role of root canal sealers and dentin surface pretreatment on pull-out strength of customized resilient ceramic posts-and-cores. BMC Oral Health, 25(1731). https://doi.org/10.1186/s12903-025-07093-w