How safe are denture relines?

We’ve recently received a number of inquiries about the potential toxicity of denture relines, so we figured it’s time for another blog post.

What’s a reline?

A reline is the procedure used to resurface the tissue side of a denture with new material. It is common to have a denture relined every few years, as a reline can extend the life of a denture and improve its fit.

Are there toxicity concerns related to relines?

As with the acrylic resin, from which dentures are made, reline materials contain residual substances that can leach from the denture and into the mouth.

“Denture relining materials contain non-reacted constituents that may leach out during use inducing local toxic or irritative effects” (Dahl et al., 2006).

The substances found to leach vary across different materials ;Brozek et al. (2011) found soft lining materials to leach MMA, ethylene glycol dimethacrylate, and dibutyl phthalate, and in other studies, phthalates were found to leach from soft-lining materials (Munksgaard, 2004; Munksgaard, 2005).

Are some types of relines safer than others?

Yes. Hard relines use acrylics; soft relines can be acrylic, vinyl, or silicone. A hard permanent reline is performed in the laboratory using denture base acrylic, while a “chairside” reline (also called a direct reline) is performed in the office. Hard permanent relines require heat curing in the laboratory, while chairside relines, when acrylic is used, rely on auto-cure acrylic (also called “self cure” or “cold cure” acrylic). Auto cure acrylics generally do not polymerize as thoroughly as heat cure acrylics, and thus are less biocompatible.

In addition, in chairside relines, the reline material is in direct contact with oral tissues as it polymerizes. In one study, five cytotoxic compounds were found to leach from hard chairside reline materials, including isobutyl methacrylate (IBMA), 1,6-hexanediol dimethacrylate (1,6-HDMA), dibutyl phthalate (DBP), methacrylic acid (MA) and benzoic acid (BA) (Chaves et al., 2010).

What can I do?

While they are certainly convenient – the procedure is performed right in the office while you wait – chairside reline materials are less biocompatible than those of hard permanent relines. For this reason, chairside relines should be avoided. If your denture needs a reline, request a hard permanent reline performed by the laboratory. You may have to wait a day or two to receive your denture, but you’ll be exposed to fewer residual chemicals. You’ll also be less likely to encounter the unpleasant smell or taste – or even worse, a burning sensation or discomfort – that some patients experience with chairside relines.

Pure Cure Dental Technology is the creator of Denture Detox, the first product to help remove toxins and allergens from dentures, and the author of the Free Report on Denture Toxicity. We invite any questions you may have about dentures, the issue of denture toxicity, or denture health in general. 

By Melissa Mesku 

Scientific studies referenced in this blog post can be found in the bibliography of our Free Report on Denture Toxicity.