NIOM has received several inquiries from Nordic dental personnel about allergies to components in various dental materials.

Epoxy resin

Question: Can a patient react against composite resin fillings when he or she has been diagnosed with a contact allergy to epoxy? Should existing composite fillings be removed, and placement of new fillings avoided? Could resin-based luting cements pose a risk of allergy?

Answer: The potential cross-reaction between BIS-GMA − a commonly used constituent of many composite resins − has been a matter of concern. However, an association has not been established. BIS-GMA has chemical similarities with epoxy, but contains an acrylic moiety, which is probably more frequently involved in contact allergy than epoxy. Generally, it appears that it is a low risk that the patient will develop contact allergy to hardened composite resin. If a patient does not indicate symptoms associated with the fillings, it is not recommended to replace them, provided they are clinically adequate. The use of resin cement for e.g. bonded ceramics should not be a concern, based on the same considerations as outlined above.


Metals in metal–ceramic restorations

Question: A dentist suspects that a patient is at risk of allergies to metals in metal–ceramic restorations. How should the topic be approached?

Answer: The metal framework of metal–ceramic restorations could contain metallic elements that are known contact allergens such as nickel, palladium, gold, cobalt and chromium. If there is a clinically relevant suspicion of contact allergy, “patch testing” (epicutaneous testing) could be a diagnostic tool to evaluate the risk of reaction to specific metals. Such testing is to be performed by a dermatologist based on referral information from the patient’s dentist or general practitioner. There exists a special patch test series with substances that are directly relevant for dental materials, but it might not be available at all dermatological/allergological clinics. The selection of materials should be done based on detailed material information and the medical dermatological assessment.



Question: A dental patient is diagnosed with allergy to colophony. What dental materials could contain colophony, and what precautions should be taken with respect to use of dental materials?

Answer: Colophony (rosin) is a natural resin that can stick to moist surfaces. The only dental product NIOM knows of is a high-fluoride anti-caries coating (Duraphat Dentalsuspension), which is classified as a drug in the Nordic countries. (There is a high-fluoride toothpaste with the same name, but it does not contain colophony.) Some previously used periodontal wound dressings could contain colophony, but NIOM is not aware of such products on the market today. Colophony could be present in some denture adhesives, but such products are not known to NIOM.


Reporting of adverse events

If there is a reaction to a specific product, it should primarily be reported to the manufacturer. In Norway there is a dedicated reporting system for dental materials. In the other Nordic countries adverse events could be reported to the national health authorities: Medical Products Agency (Sweden), Danish Health and Medicines Authority (Denmark), Valvira – National Supervisory Authority for Welfare and Health (Finland).