| Abstract|| |
Amalgam is one of the most widely used restorative material in dentistry. However due to continuous low level release of mercury (Hg) from amalgam Fillings, its safety and wide scale use has been questioned. The main concerns relate to the potential toxic effects of Hg and the possibility that Hg may induce adverse immunological effects. With regard to the latter. there have been a number of reports suggesting that amalgam fillings may induce oral lichen planus (OLP) like or oral Lichenoid lesions(OLL)Here we present a case report of Amalgam Associated Oral Lichenoid Reaction (AAOLR) or Amalgam Contact Hypersensitivity Lesions( ACHL)s with emphasis on current review literature.
Keywords: AAOLR, ACHL, Amalgam, Lichenoid reaction
|How to cite this article:|
Sunith M, Ramesh Kumar M, Shoba K, Jayasree S. Amalgam associated oral lichenoid reaction. J Conserv Dent 2006;9:148-51
| Introduction|| |
Silver amalgam has been used as a dental restorative material for more than 150 years. Even today, with the advent of new synthetic non-metallic materials and novel time-saving procedures, silver amalgam is the most widely used and cost-effective dental material in restorative dentistry. Its superior compressive strength and minimal technique sensitivity makes it an ideal material for posterior restorations and core build ups. In addition to corrosion and metallic colour, amalgam has got a major disadvantage. Amalgam fillings are in direct contact with the oral mucosa and may directly alter the antigenicity of basal keratinocytes by the release of mercury and other metal salts as corrosion products ,, In susceptible individuals, therefore, amalgam fillings nay induce amalgam-contact hypersensitivity lesions (ACHL)s with features similar to OLP Such lesions are likely to occur on mucosal surfaces in intimate contact with amalgam fillings and could be expected to improve following removal of the fillings  .
Many researchers had reported lichenoid lesions in susceptible individuals associated with amalgam restorations. Pinkus in 1973 coined the term Lichenoid lesion. Koch P et al 1995  proposed "Dental restoration metal intolerance syndrome" Skoglund A 1994  proved that removal of amalgam usually affects the lesions favorably and that epicutaneous patch tests are of little prognostic value in patients with oral mucosal lesions of lichenoid character. Bratel J et al 1996  came into a conclusion that vast majority of contact lesions (CL) resolve following selective replacement of restorations of dental amalgam, provided that a correct clinical diagnosis is established Pang BK et al 1995  proved that replacement of amalgam with other dental fillings usually results in resolution of OLL and is recommended for cases with positive patch test reactions to mercury compounds. Same conclusion was made by Issa Y et al , in the articles published in 2004 and 2005 and Dunsche et al in 2003  Ostman P O et al 1996  on his study conducted in 51 patients stated that various etiologic factors are involved in lichenoid reactions and that the effect of removal of amalgam fillings cannot be predicted by epicutaneous patch testing and biopsies. Dekker SK et al 2004  concluded that contact allergy to mercury compounds is important in the pathogenesis of oral lichen planus, especially if there is close contact with amalgam fillings and if no concomitant cutaneous lichen planus is present
| Case report|| |
A female patient 54 yrs of age reported to Dental College Calicut complaining of burning sensation of right buccal mucosa of I month duration. A detailed history was taken and no relevant H/O (1) drugs (2) skin diseases such as lichen planus, lupus erythematosus etc (3) Graft-versus-host disease. There is no other relevant medical history. Dental history: - she had underwent extraction of 17 and 26 and also an amalgam filling on 16 two months before.
On examination an erythematous area interspersed with white striac of size 2cm x 2cm was found on right buccal mucosa adjacent to occlusal plane of 16. Apart from this white lesion other parts of oral mucosa appeared apparently normal. Dental examination revealed a distoocclusal amalgam filling on 16. Healing extraction socket was found in relation to 17 and 26.
On inspection the filling was intact and the lesion was on the buccal mucosa adjacent to the filling. [Figure 1]
The lesion was non scrapable and tested Candida negative.
Cutaneous patch tests
A cutaneous patch test was done to detect contact hypersensitivity. Alloy powder and mix were tested separately on skin on the back of the patient
| Results|| |
Patient reported back after 48 hrs with the complaint of itching on the mix patch [Alloy + Hg] [Figure 2]. Patches were removed and examined. A slight erythematous reaction was noted on mix patch area. A provisional diagnosis of AAOLR was made. It was decided to replace amalgam restoration with a non-metallic interim restoration and follow up the case.
The distoocclusal amalgam restoration of 16 was replaced with a Type 11 GIC. Patient was asked to report after 2 wks. Patient reported after 2 wks with a relief of symptoms. O/E there was a reduction in size and severity of the lesions [Figure 3]. One more review conducted after 3 months revealed complete clinical healing of lesion [Figure 4].
| Discussion|| |
From this case report it is evident that amalgam fillings may induce adverse immunological effects. Amalgam restorations may induce lichenoid reactions in susceptible individuals ,, . The typical appearance of these lesions usually confirms diagnosis in most cases. Clinical features as well as the results of skin patch testing against Hg and amalgam can help in diagnosis  . Removal of these fillings results in clinical resolution of the lesions ,,,, .The predictability of patch test seems to be of little benefit in majority of cases , .Patch tests are applied for 72-96h, but some patients develop responses to mercury or amalgam up to 14 days or later. This may be the most likely explanation for the poor predictability of patch tests in these type of lesions  .It is clear that patch test methodology for identifying AAOLR needs refining  . In the past lichenoid lesions caused by contact with restorations have been attributed to galvanic reactions between dissimilar metals in close contact  . Now researchers did not support the concept of "galvanic" lesions. Rather, these lesions appear to be the result of cell-mediated contact hypersensitivity responses to mercury or amalgam in susceptible individuals who have been sensitized through long time exposure ,, . With the exception of specific examples such as ACHL, we are unable to pinpoint the real cause in the majority of patients with OLP. Indeed, OLP may represent a group of diseases, each with a different cause but sharing a similar clinical outcome. ACHL may represent the easiest subgroup of OLP to distinguish, because of its association with amalgam  .
In general, as we can't treat the underlying cause of OLP, treatment usually results in recurrence. In the case of ACHL, however, we can treat it by covering or replacing contacting amalgam fillings. In patients who are patch test positive for mercury or amalgam, or in whom a strong clinical association between their lesions and restorations exist, such treatment is highly effective.
| Conclusion|| |
Silver amalgam has been used as a dental restorative material for more than 150 years. Even today, with the advent of new synthetic non-metallic materials, silver amalgam is the most widely used and cost-effective dental material in restorative dentistry. Local allergic reactions are rare, and when they occur, they can be eliminated by the substitution with another material. Available scientific evidence does not justify the discontinuation of the use of amalgam, nor does it recommends the removal and replacement of satisfactory amalgam fillings with other materials
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Department of Conservative Dentistry & Endodontics, Govt. Dental College, Calicut, Kerala
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4]