Dentures and Health

Dentures are meant to improve our quality of life. We rely on dentures for a natural smile and the confidence that comes with it. All we have asked of our dentures is that they fit well, function properly, and look great.

But something important has been overlooked: Conventional resin-based dentures contain toxic and allergenic substances, and studies show that these substances can leach out of dentures and into the mouth.


Problems


Conventional dentures leach toxic and allergenic substances

Our results indicate that purported allergens exist in the resin base and can be eluted into the oral cavity, even in patients using an old denture for a period of nearly 30 years [8].

Dentures are strong and relatively durable, which may lead people to assume that dentures are also biologically inert. For a denture to be completely inert, and fully biocompatible, it would have to maintain its integrity by not releasing substances and not absorbing substances. However, conventional resin-based dentures can absorb substances [12] and numerous studies indicate that they can also leach the substances they contain [2-18].

At issue is the biocompatibility of the pink base that forms the gums of the denture. The most common type of denture—which we refer to as a conventional denture—is a full or partial denture whose base is formed from the acrylic resin methyl methacrylate (MMA). Depending on how the denture was made, substances can leach out of the denture base. Because dentures are worn in the mouth, and because of the warm and aqueous nature of the oral environment, substances released from dentures may leach into the mouth while the denture is worn. Of those substances, some are toxic or allergenic to the oral environment [2][4][6][8][11][13][16][17][18][19].

Dentures that have been relined may contain additional toxic and allergenic substances, as reline materials contain additional substances [20][21]. It is common for many denture wearers to have their denture relined at some point, which introduces additional substances that may leach into the mouth. Furthermore, new studies indicate that some denture cleaners may have a corrosive effect on reline material, and may accelerate the loss of toxic and allergenic substances, including phthalates [21].

The substances contained in a particular denture, and the degree to which it leaches, depend on the materials and methods used in its fabrication. However, the methods by which dentures are crafted vary widely. There are no quality control standards that are enforced across the industry. In the US, some dental laboratories may have their dentures manufactured abroad. This means that the quality of the denture that a patient receives, and its degree of safety, is largely left to chance.

Acrylic resins are widely used in the fabrication of denture bases and have been shown to be cytotoxic as a result of substances that leach from the resin [2].

Acrylic resin remains the material of choice for denture fabrication because of its superior aesthetic and mechanical properties [2]; so, too, remain concerns regarding its biocompatibility.

Which substances have been found to leach from conventional resin-based dentures? View the list »

methyl methacrylate (MMA) [2-9]
2-hydroxyethyl methacrylate (HEMA) [5]
formaldehyde [5][10]
dibutyl phthalate [6][7]
biphenyl [6][7]
phenyl benzoate [6][7]
copper [7]
phthalates [7]
dicyclohexyl phthalate [7]
phenyl 2-hydroxybenzoate (phenyl salicylate) [7]
hydroquinone (HQ) [8]
benzoyl peroxide (BPO) [8] dibenzoyl peroxide (DBP)[14]
methyl benzoate (MB) [8]
ethyleneglycol dimethacrylate (DME) [8]
benzoic acid (BA) [8][9]
2-methylpropenoic acid (methacrylic acid or MAA) [9]
cadmium [19][23]


Health Concerns

It may be disconcerting to learn that conventional resin-based dentures have been found to leach substances, particularly if you or someone you know wears dentures. Concern arises when considering the possible implications this may have for a denture wearer’s health. Here we’ll look at what studies have to say about the health implications of wearing dentures that leach.

Wearing dental acrylic prosthesis causes adverse reactions to oral tissues due to bioactive leachables from resins. . . [3]

A range of effects may result from wearing dentures that leach. Reported effects include irritation [2][4][12][13], sensitization [2], inflammation [13], allergic reactions [4][8][16][17], stomatitis [16], burning mouth syndrome [18], cell death in the oral cavity [19], and potentially more serious adverse health effects.

More »

The primary substance that leaches from denture base resins is residual methyl methacrylate monomer [2]. What exactly is it?

Residual monomer is the leftover methyl methacrylate (MMA) monomer material that did not react during the chemical change a denture undergoes. Dentures are made while the material is soft, and then must undergo a polymerization process to make them hard enough to wear. The less thorough this process, the more material will remain unreacted, and it is this “residual” monomer material is the primary substance that leaches out of conventional dentures. Additionally, some acrylics are more prone to leaching residual monomer.

“Methyl methacrylate (MMA), a monomer of acrylic resin, has a wide variety of dental, medical and industrial applications. Concerns have been raised regarding its potential toxicity in dental use, both for the patient and also in the workplace. Dental patients are also exposed to MMA leached from some dental appliances and the effects, at least in vitro, appear toxic to cells and may cause local mucosal irritation or even an allergic reaction.” [4].

How might residual monomer affect a denture wearer’s health?

Residual methyl methacrylate (MMA) may leach from the acrylic resin denture bases and have adverse effects on the oral mucosa [11]

Residual monomer has been the subject of a number of studies that substantiate its deleterious effects. There are a number of possible health effects caused by wearing a denture that leaches residual monomer. “Numerous reports suggest that residual monomer may be responsible for mucosal irritation and sensitization of tissues” [2]. In the study, “Leaching and cytotoxicity of formaldehyde and methyl methacrylate from acrylic resin denture base materials,” the authors stated, “Acrylic resin dentures have the potential to elicit irritation, inflammation, and an allergic response of the oral mucosa” [13]. Due to these health effects, it is “imperative to adopt every possible means to minimize residual monomer content in heat cured resins”[22] and it has been recommended that “techniques should be employed to reduce patients’ exposure to MMA during dental procedures in order to reduce the risks of possible complications”[4].



Solutions


Toward a safer and more biocompatible denture

Biocompatibility
is the ability of a polymer material or device to remain inert during use. Dentures are polymer devices, most commonly made from acrylic resin. Full biocompatibility for a denture would mean that no substances leach out, and nothing seeps in.

Dentures are typically thought to be completely inert, but scientific literature indicates otherwise. Studies have shown that conventional resin-based dentures can leach substances, and unfortunately those substances are in many instances toxic or allergenic. While the substances that leach are small in amount, it can be discomforting to know that a device worn intimately in the mouth is able to release chemical components.

Our first product, Pure Cure Denture Detox®, enables you to eliminate as many toxins and allergens from the denture base as possible, and to render the denture more biologically inert so that it will not leach.

Learn about our products

Visit DentureDetox.com »



View all citations on this page »

[2] Jorge, et al., 2003

J. H. Jorge, E. T. Giampaolo, A. L. Machado, C. E. Vergani (August 2003). “Cytotoxicity of denture base acrylic resins: a literature review.” Journal of Prosthetic Dentistry 90 (2): 190-3. PMID 12886213

[3] Çelebi, et al., 2008

N. Çelebi, B. Yüzügüllü, Ş. Canay, Ü. Yücel (March 2008). “Effect of polymerization methods on the residual monomer level of acrylic resin denture base polymers.” Materials Research Innovations 19 (3): 201-206.

[4] Leggat and Kedjarune, 2003

P. A. Leggat, U. Kedjarune (June 2003). “Toxicity of methyl methacrylate in dentistry.” International Dental Journal, 53 (3): 126–31. doi: 10.1111/j.1875-595X.2003.tb00736.x PMID 12873108

[5] Kopperud, et al., 2011

H. M. Kopperud, I. S. Kleven, H. Wellendorf (February 2011). “Identification and quantification of leachable substances from polymer-based orthodontic base-plate materials.” European Journal of Orthodontics 33 (1): 26-31. PMID 20624754

[6] Lygre, et al., 1993

H. Lygre, E. Solheim, N. R. Gjerdet, E. Berg (February 1993). “Leaching of organic additives from dentures in vivo.” Acta Odontologica Scandinavica 51 (1): 45-51. PMID 8451923

[7] Lygre, et al., 1995

H. Lygre, E. Solheim, N. R. Gjerdet (April 1995). “Leaching from denture base materials in vitro.” Acta Odontologica Scandinavica 53 (2): 75-80. PMID 7610779

[8] Mikai, et al., 2006

M. Mikai, M. Koike, H. Fujii (March 2006). “Quantitative analysis of allergenic ingredients in eluate extracted from used denture base resin.” Journal of Oral Rehabilitation 33 (3): 216-20. PMID 16512888

[9] Koda, et al., 1989

T. Koda, H. Tsuchiya, M. Yamauchi, Y. Hoshino, N. Takagi, J. Kawano (April 1989). “High-performance liquid chromatographic estimation of eluates from denture base polymers.” Journal of Dentistry 17 (2): 84-9. PMID 2732369

[10] Tsuchiya, et al., 1993

H. Tsuchiya, Y. Hoshino, H. Kato, N. Takagi (August 1993). “Flow injection analysis of formaldehyde leached from denture-base acrylic resins.” Journal of Dentistry 21 (4): 240-3. PMID 8354750

[11] Bural, et al., 2011

C. Bural, E. Aktaş, G. Deniz, Y. Ünlüçerçi, G. Bayraktar (August 2011). “Effect of leaching residual methyl methacrylate concentrations on in vitro cytotoxicity of heat polymerized denture base acrylic resin processed with different polymerization cycles.” Journal of Applied Oral Science 19 (4): 306-12. PMID 21956586

[12] Pfeiffer and Rosenbauer, 2004

P. Pfeiffer, E. U. Rosenbauer (July 2004). “Residual methyl methacrylate monomer, water sorption, and water solubility of hypoallergenic denture base materials.” Journal of Prosthetic Dentistry 92 (1): 72-78. PMID 15232564

[13] Tsuchiya, et al., 1994

H. Tsuchiya, Y. Hoshino, K. Tajima, N. Takagi (June 1994). “Leaching and cytotoxicity of formaldehyde and methyl methacrylate from acrylic resin denture base materials.” The Journal of Prosthetic Dentistry 71 (6): 618-24. PMID 8040827

[14] Boeckler, et al., 2008

A. F. Boeckler, D. Morton, S. Poser, K. E. Dette (December 2008). “Release of dibenzoyl peroxide from polymethyl methacrylate denture base resins: an in vitro evaluation.” Dental Materials 24 (12): 1602-7. PMID 18471871

[15] Sofou, et al., 2005

A. Sofou, I. Tsoupi, J. Emmanouil, M. Karayannis (2005). “HPLC determination of residual monomers released from heat-cured acrylic resins.” Analytical and Bioanalytical Chemistry 381 (7): 1336-46. PMID 15759139

[16] Koutis and Freeman, 2001

D. Koutis, S. Freeman (August 2001). “Allergic contact stomatitis caused by acrylic monomer in a denture.” Australasian Journal of Dermatology 42 (3): 202-6. PMID 11488717

[17] Gonçalves, et al., 2006

T. S. Gonçalves, M. A. Morganti, L. C. Campos, S. M. D. Rizzatto, L. M. Menezes (March 2006). “Allergy to auto-polymerized acrylic resin in an orthodontic patient.” American Journal of Orthodontics & Dentofacial Orthopedics 29 (3): 431-5. PMID 16527642

[18] Feilzer, 2006

A. J. Feilzer (September 2009). “Burning mouth caused by denture material.” Nederlands Tijdschrirft voor Tandheelkunde 116 (9): 472d-4. PMID 19791489

[19] Cimpan, et al., 2000

M. R. Cimpan, L. I. Cressey, N. Skaug, A. Halstensen, S. A. Lie, B. T. Gjertsen, R. Matre (February 2000). “Patterns of cell death induced by eluates from denture base acrylic resins in U-937 human monoblastoid cells.” European Journal of Oral Sciences 108 (1): 59-69. PMID 10706479

[20] Chaves, et al., 2010

C. A. Chaves, A. L. Machado, I. Z. Carlos, E. T. Giampaolo, A. C. Pavarina, C. E. Vergani (October 2010). “Cytotoxicity of monomers, plasticizer and degradation by-products released from dental hard chairside reline resins.” Dental Materials 26 (10): 1017-23. PMID 20650509

[21] Brożek, et al., 2011

R. Brożek, R. Koczorowski, R. Rogalewicz, A. Voelkel, B. Czarnecka, J. W. Nicholson (March 2011). “Effect of denture cleansers on chemical and mechanical behavior of selected soft lining materials.” Dental Materials 27 (3): 281-90. PMID 21144576

[22] Pradeep and Sreekumar, 2012

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[23] Purello-D'Ambrosio, et al., 2000

F. Purello-D'Ambrosio, S. Gangemi, P. Minciullo, L. Ricciardi, R. A. Merendino (March-April 2000). “Burning mouth syndrome due to cadmium in a denture wearer.” Journal of Investigational Allergology and Clinical Immunology 10 (2): 105-6. PMID 10880000