Figure 1. Polyamide denture on a plaster model

Nylon dentures may be a good alternative

Polyamide, or nylon, is an alternative material for removable dentures. They do not release allergens and have acceptable water sorption. Nylon dentures are thus promising, although they still lack clinical documentation.

Polyamide, commonly named nylon, has been advocated as a flexible, non-allergenic alternative to PMMA (Figure 1). Acceptable water sorption and god biocompatibility are parameters that ensure patient satisfaction. Our study showed for commercial polyamides that the water sorption was higher for one nylon material (Breflex) and lower for the other (Valplast) compared to a PMMA (Ivocap High Impact) material (Figure 2). Both tested polyamide materials had a net uptake of water as seen from the negative water solubility values in Figure 2. This may affect the mechanical properties over time. All values were, however, within the requirements from the international standardisation organisation (ISO) for denture base materials.

Figure 2. Water sorption and solubility of two polyamide denture base materials (Breflex and Valplast) compared to traditional PMMA (HIP).

We also analysed substances released from the processed polyamide materials after immersion in 75 % ethanol for 3 days. We could not detect leaching of known allergens from either of the nylon materials. The release of a monomeric substance from Valplast was quantified to 0.17 per mille and none from Breflex. The materials were considered to be safe to use for patients with allergic reactions to acrylates.

The available scientific clinical documentation is, however, too limited to decide clinical success or safety. One clinical study (Med J Armed Forces India, 2015; 71-Suppl 2: S306–S312) concludes with favourable clinical results (aesthetics and overall patient satisfaction) for flexible partial dentures. It is, however, recommended that polyamide dentures should be used with caution until there is more evidence.

This study was conducted in cooperation between the University of Bergen and NIOM, including the participation from a student following the Dental Student Research Programme.

The newsletter is based on the article:
Water sorption and solubility of polyamide denture base materials.
Nguyen LG, Kopperud HM, Øilo M
Acta Biomaterialia Odontologica Scandinavica. 2017; 3: 47-52.
www.tandfonline.com/doi/abs/10.1080/23337931.2017.1326009 (full-text available)

Download NIOM Newsletter September 2017