Goodbye Metal Mouth – Phillip Silver

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  Posted by: Dental Design      6th February 2018

If you work in the dental sector you are well aware of the concerns that patients have around dental toxicity. It is a controversial issue, but recently it has resulted in an increasing number of patients who are reluctant to accept metal dental materials. Generally, people don’t like the look of metal in the mouth but they also worry about the constituents and side effects of alloys and metallic components. Of course, regulatory bodies and agencies in the UK control the safety and quality of all dental devices but some patients have metal allergies or suspect that they may be hypersensitive to metal.

One of the main concerns expressed by patients relates to dental amalgam. The fear of dental toxicity as a result of the mercury content of amalgam fillings is widespread. Amalgam fillings are made up of a blend of metals including silver, mercury, and small amounts of tin, copper and/or zinc. This material has been used in dentistry for over 150 years and although research confirms that amalgam restorations leach mercury, there is no evidence to suggest that this results in adverse health effects. It is effective and durable and is still considered to be a safe restorative option for both children and adults.[1] Furthermore, the Oral Health Foundation states that confirmed cases of allergic reaction to amalgam are extremely rare. Out of the thousands of millions of amalgam fillings that have been placed, fewer than 100 cases of an allergic reaction have been reported worldwide.[2] Nevertheless, patients and practitioners are moving away from amalgam and opting for composite materials.

Dental implants, orthodontic appliances, restorations and dentures often contain metals including, but not limited to, gold, mercury-containing amalgam, nitinol/nickel, titanium, and palladium. This indicates that, in dentistry, the potential for metallic allergens is sizable.[3] Certainly, the materials and components used in dental procedures are not natural tissues and are never going to be accepted by the body in the same way. Dental toxicity can occur when the material placed in an individual’s mouth causes their immune system to react or reject it.

Metal hypersensitivity in particular is a common condition that affects 10 to 15 per cent of the general population and it has been estimated that up 17 per cent of women and 3 per cent of men are allergic to nickel and up to 3 per cent are allergic to cobalt and chromium. Gold and palladium have also drawn increased attention recently, as the prevalence of contact allergy to these metals is high.[4],[5] When the immune system begins attacking metal ions that come into contact with the patient, it can trigger a variety of symptoms from mucosal changes, skin disease to excessive fatigue and autoimmune diseases.[6]

Signs of an oral allergy include reddening of the oral mucosa, swelling of the lips, purple patches on the palate, mouth ulcers, gingivitis, areas of depapillation on the tongue, eczematous eruption and lichenoid reactions. In acute forms, oral allergy can cause in swelling of the upper respiratory tract and can become life threatening. Patients with oral allergy may report burning or tingling sensations, with or without swelling, oral dryness and loss of taste as well as more general symptoms such as headache, dyspepsia, asthenia, arthralgia and myalgia.[7] Recently it has even been suggested that patients that have multiple allergies or a history of allergy to metal have a greater risk of hypersensitivity to metal implants even though titanium has previously been considered biologically inert.7 Over the last few years, practitioners may have noted that bioceramics such as zirconia (zirconium dioxide) have now entered the modern implant market.

Interestingly, for patients that wish to opt for removable partial dentures (RPD) there is now a biocompatible material that can be offered as an alternative to metal. Ultaire™ AKP made by Solvay Dental 360™ is a high performance polymer that has been custom-designed for RPD application. RPD frames fabricated from this material are not harmful to natural tissue and offer a viable option for patients that are both susceptible to allergies and those that would simply prefer not have metal in the mouth. Ultaire™ AKP is thin and lightweight and has bone-like properties that provide elasticity and flexural strength to withstand loading. These frames are tooth supported, comfortable and stable with a superior overall fit that could even limit future bone loss.

When choosing materials for dental applications it is essential to consider a number of factors including corrosion behaviour, mechanical properties, cost, availability, appearance and biocompatibility. In the interests of your patients and the future of your practice, take the time to explore the new generation of materials that are now reaching the UK market.


For more information about Solvay Dental 360™, Ultaire™ AKP and Dentivera™ milling discs, please visit


[1] Rathore M et al. The Dental Amalgam Toxicity Fear: A myth or actuality. Toxicol Int. 2012 May-Aug; 19(2): 81–8. [Accessed 26th June 2017]

[2] Oral Health Foundation formerly British Dental Health Foundation Policy Statement Dental Amalgam. 2011. [Accessed 26th June 2017]

[3] Teo ZWW et al, Hypersensitivity reactions to implanted metal devices: Facts and Fictions. J Investig Allergol Clin Immunol 2016; Vol. 26(5): 279-294. [Accessed 26th June 2017]

[4] Thyssen JP et al. Metal allergy–a review on exposures, penetration, genetics, prevalence, and clinical implications. Chem Res Toxicol. 2010 Feb 15;23(2):309-18. [Accessed 26th June 2017]

[5] Raap U et al. Investigation of contact allergy to dental metals in 206 patients. 2009. Contact Dermatitis, 60: 339–343. doi:10.1111/j.1600-0536.2009.01524.x

[Accessed 26th June 2017]

[6] Stejskal V et al. Diagnosis and treatment of metal-induced side effects. Neuro Endocrinol Lett. 2006 Dec;27 Suppl 1:7-16. [Accessed 26th June 2017]

[7] Evrard L. Titanium: A New Allergen. Chapter 23 from Implant Dentistry – A Rapidly Evolving Practice. [Accessed 26th June 2017]


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