Investigation of contact allergy by patch testing with dental series

Swetha Sunny, Kurian (2013) Investigation of contact allergy by patch testing with dental series. Masters thesis, PSG Institute of Medical Sciences and Research, Coimbatore.


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SUMMARY AND CONCLUSION: Patients undergoing dental therapy such as root canal treatment, orthodontic treatment, prosthodontic treatment and dental implants have dental materials placed in the oral cavity for extended periods of time. Examples of such treatments are dental fillings, braces, dentures and implanted teeth. Many of the substances used for these treatments are known to cause allergic contact dermatitis (ACD). ACD in the oral cavity can manifest in various ways such as oral lichenoid lesions (OLLs), gingivostomatitis, cheilitis, burning mouth, lip/facial swelling or oral ulcers. Lichenoid skin eruptions and eczema are also known to occur. Although the oral mucosa is constantly exposed to a large number of potential allergens and irritants, it is worthwhile to assess whether these patients have a specific allergy to dental materials. Dental personnel handling the raw materials used for dental products are also at risk of developing ACD. Dentists mainly use amalgams and composites as fillings for dental cavities. Dental amalgams are composed of a mixture of metals and it is usually an alloy of mercury, silver, tin, copper and other trace metals. All these are potential allergens to dental personnel and patients. Dental composite resin is used to fill dental cavities. This composite resin has to undergo a curing process before it can be used. This curing process involves linking of acrylic monomers to form polymers. These monomers are mainly responsible for ACD. To produce dental composite resin, the dental personnel mix the specific acrylates with benzoyl peroxide and induce a polymerization process. This dough is then hardened by using heat or light. If this hardening has to occur at room temperature the reaction needs an accelerator (activator). Certain other additives called inhibitors are used to prevent unintended spontaneous polymerization. In addition to acrylates, both accelerators and inhibitors can cause sensitization. Unpolymerized material that remains back after the curing process can leach out and act as an allergen for dental patients but as the contact time is short, they are less prone to develop ACD. Acrylic dentures also require a similar curing process. Both dental personnel and patients are at risk for ACD to acrylates in dentures. Acrylic monomers can penetrate surgical latex gloves so dental personnel are not protected from coming into contact with these substances and are at a higher risk of developing ACD. Special types of gloves like 4H-gloves have been advised in these patients but they are not popular as these gloves are expensive and have a poor anatomical fit. Our study focused on two groups of people. One group was patients with previous dental treatment that presented with complaints of oral lesions or skin lesions that appeared after the dental treatment. The other group was dental personnel who handle dental materials with complaints of hand dermatitis. Since we suspected ACD, which is a type of delayed hypersensitivity reaction, we patch tested these two groups with Chemotechnique dental series. Readings were taken at 48, 72 and 96 hrs. Most of the dental patients had amalgam fillings and most of them had oral lichenoid lesions (OLLs). The most common allergens were metals such as nickel, copper, gold, potassium and mercury. Mercury and copper are found in dental amalgam and there could be a relevance of the positive patch test findings in these patients. Nickel is a common sensitizer in the general population and its relevance in this study is uncertain. The patients who tested positive to gold were all females (who regularly wear gold jewelry) and none of these patients had any dental treatment with gold in the oral cavity so the relevance gold allergy was also uncertain in our study. None of our patients tested positive to any of the acrylates. As patients come into contact with uncured monomer acrylics for very short periods of time, this lack of positivity is not relevant. Acrylic allergy in denture-wearers has been reported but none of our patients had history of wearing dentures. Studies have shown that removal of dental amalgams in patients with proven amalgam allergy has provided symptomatic relief with partial or complete healing of oral lesions. Other studies have shown relief of symptoms in patients even without showing sensitivity. This is postulated as a result of an irritant reaction to mercury vapors from the dental amalgam. None of our patients had their fillings removed so this correlation could not be assessed in our study. Acrylic allergy in dental personnel is well documented. 5 out of 7 of the dental personnel tested in our study showed positivity to at least one acrylate. The most common acrylates which showed positivity in our study were BIS-GMA, BIS-MA and 1,4-Butanediol dimethacrylate. In one study it was suggested that 2-HEMA (2-hydroxyethyl methacrylate) and bis-GMA were enough to screen patients for acrylate allergy. ACD to acrylates in dental personnel is difficult to manage as they cannot avoid coming into contact with these materials. They can also be advised a replacement of treatment if found to be allergic to any of the constituents of their treatment. So if patients with amalgam fillings present with allergy, they can be advised for it to be changed to composite filling and vice versa. Patch testing with dental series can be useful in patients with severe oral symptoms where there could be resolution of their complaints after removal of the offending agent. Patch testing is a simple, scientific and cost effective tool that can be used to detect contact allergies and to eliminate the offending agent and hence giving symptomatic relief to the patients.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Investigation ; contact allergy ; patch testing ; dental series.
Subjects: MEDICAL > Dermatology Venereology and Leprosy
Depositing User: Punitha K
Date Deposited: 21 Jun 2018 14:23
Last Modified: 22 Jun 2018 02:57

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