Phillip Silver considers how advances in technology are improving options for patients.
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. Furthermore, the Oral Health Foundation states that confirmed cases of allergic reaction to amalgam are extremely rare. Out of the billions of amalgam fillings that have been placed, fewer than 100 cases of an allergic reaction have been reported worldwide. 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. 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 to 17 per cent of women and three per cent of men are allergic to nickel and up to three 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. 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.
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. 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. 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 are now biocompatible materials that can be offered as an alternative to metal. For example 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 to have metal in the mouth.
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.
References available on request.