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Table of Contents
Year : 2020  |  Volume : 10  |  Issue : 2  |  Page : 91-94

Contact lichenoid reaction secondary to cast metal and amalgam restorations

Department of Prosthodontics, The Oxford Dental College, Bengaluru, Karnataka, India

Date of Submission24-Feb-2020
Date of Acceptance28-Apr-2020
Date of Web Publication21-Aug-2020

Correspondence Address:
Dr. K Sasirekha
#10/A, Sri Mahi Comforts, Beside Oxford College Backgate, Hongasandra, Begur Road, Bommanahalli, Bengaluru - 560 068, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jid.jid_7_20

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Hypersensitivity reactions to dental restorative materials such as metals and amalgam may induce localized lesions in oral tissues contacting the restoration, usually manifested as lichenoid reactions. It is important to recognize and diagnose the lesion and etiology and further provide a suitable alternative restorative option for the patient. This article describes a case report of lichenoid reaction secondary to cast metal and amalgam restorations and sequential management of the same.

Keywords: Amalgam restorations, cast metal prosthesis, hypersensitivity reactions, lichenoid reaction

How to cite this article:
Dayalan M, Savitha P N, Sasirekha K, Nikhita P. Contact lichenoid reaction secondary to cast metal and amalgam restorations. J Interdiscip Dentistry 2020;10:91-4

How to cite this URL:
Dayalan M, Savitha P N, Sasirekha K, Nikhita P. Contact lichenoid reaction secondary to cast metal and amalgam restorations. J Interdiscip Dentistry [serial online] 2020 [cited 2023 Feb 2];10:91-4. Available from: https://www.jidonline.com/text.asp?2020/10/2/91/292922

   Clinical Relevance to Interdisciplinary Dentistry Top

Dental alloys such as cast metal restorations and amalgam are indispensible in various branches of dentistry. However, some patients exhibit allergic reactions to these materials such as lichenoid reactions. A timely diagnosis, removal of the etiology and provision of a suitable alternative could be a clinical challenge, given its similarity to other oral pathologies.

   Introduction Top

A substantial proportion of the population use prostheses and appliances which are composed of various dental alloys. These restorations may be associated with various effects on oral health such as burning mouth syndrome, oral pigmentation, hypersensitivity, lichenoid reactions, and genotoxic and cytotoxic effects.[1] Lichenoid reactions are indistinguishable histologically and clinically from oral lichen planus. However, a known factor can be identified in case of the former lesions which when identified and removed causes its regression. In some patients, oral lichenoid reactions appear as a result of chronic irritation or a delayed hypersensitivity reaction.[2] Although dental amalgam is the most commonly implicated dental material for causing lichenoid reactions,[3] other materials may also be involved such as cobalt, chromium, nickel, palladium, and mercury.[4] The reactions to these metals are quite rare, thus making this case a unique one. Nickel allergy is more common in women (10%) than men (1%), whereas it is the opposite in case of chromium allergy (10% in males and 3% in females). In a study by Clayton et al. in 2006, it was seen that out of 500 children tested for allergic reactions to metals, 133 children had a positive reaction, out of which nickel sulfate gave the most frequent positive test with 44 reactions (33%), although it was found to be relevant in only 3 cases.[5],[6]

   Case Report Top

A 38-year-old female patient reported to our department with a chief complaint of burning sensation and black discoloration on her tongue and inner surface of her cheeks which she reported to have started after placement of metal crowns 5 years ago. The discoloration started on her right buccal mucosa and progressed to her left buccal mucosa and then the tongue. The burning sensation was aggravated on eating hot and spicy food and was relieved on consuming sweets and sugar.

Treatment plan

Clinical evaluation revealed grayish-black diffuse pigmentation with white striations seen on the buccal mucosa at the level of occlusal plane and lateral borders of the tongue [Figure 1]. Cast metal crowns (all metal and porcelain-fused-to-metal [PFM] crowns) and amalgam restorations were also noted on her posterior teeth adjacent to the presenting lesion [Figure 2]. The patient did not report any relevant medical or drug history that could have contributed to the lesion. The treatment plan included removal of the metal restorations, biopsy of the lesion, replacement with nonmetallic restorations, and evaluation of the progression or regression of the lesion.
Figure 1: Grayish-black diffuse pigmentation with white striations seen on the buccal mucosa at the level of occlusal plane and lateral borders of the tongue

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Figure 2: Cast metal crowns (all metal and porcelain-fused-to-metal crowns) and amalgam restorations were also noted on her posterior teeth adjacent to the presenting lesion

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Clinical procedure

An excisional biopsy of the right buccal mucosa was performed to confirm the same. Hyperplastic parakeratotic stratified squamous epithelium with areas of squamous cell degeneration was seen. Fibrovascular connective tissue, melanophages and focal areas of dense inflammatory infiltrate, predominantly lymphocytes, plasma cells, and mast cells were also seen. The deeper connective tissue showed normal salivary glands, adipose tissue, and muscles. The histopathological diagnosis was given as an oral lichenoid reaction. Following this, amalgam restorations were removed and glass-ionomer cement restorations were placed. The cast metal crowns (all metal and PFM crowns) were removed, impressions of the maxillary and mandibular arches made, wax-up and mock-up done, and heat-cured acrylic provisional crowns placed [Figure 3]. Then, the chemical composition of the cast metal crowns was tested using inductively coupled plasma optical emission spectrometry at Analytical Research and Metallurgical Laboratories, Bangalore. The PFM crowns showed a composition of 30.26% nickel, 0.023% cobalt, and 8.73% chromium and the rest, ceramic. The presence of high quantity of nickel, a well-known allergen, was revealed.[7] The final diagnosis was given as a contact lichenoid reaction secondary to cast metal crowns and amalgam restorations. A 3-month follow-up of the patient was done to evaluate the progression or regression of the lesion at a monthly interval. At 1-month follow-up, regression of the lesion was evident clinically (reduction in size but deepened pigmentation which will eventually subside) with total relief of burning sensation [Figure 4]. Final restorations of all-ceramic crowns (zirconia) and composite restorations have been planned.
Figure 3: The cast metal crowns (all metal and porcelain-fused-to-metal crowns) were removed and heat-cured acrylic provisional crowns placed

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Figure 4: At 1-month follow-up, regression of the lesion was evident clinically with total relief of burning sensation

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   Discussion Top

The term lichen refers to a group of skin diseases characterized by eruptive skin lesions which are grouped together as they resemble the alga lichen found growing on rocks.[8] Lichen planus is a relatively common autoimmune disease that affects the skin and mucosa. A similar clinical and histological lesion is called lichenoid reaction which is induced by external factors which could be either topical or systemic. This mucosal reaction is also seen commonly in users of areca nut/tobacco products. A number of triggering factors such as restorative materials, graft-versus-host reaction, and a broad group of drugs are known to cause lichenoid reaction. Lichenoid reactions have been classified based on their etiology into four types depending on the triggering factors – lichenoid reaction associated with amalgam restoration, drug-related lichenoid reaction, lichenoid reaction associated with graft-versus-host reaction, and lichenoid reaction unclassified which cannot be categorized into any of the other types.[9]

The biocompatibility of dental materials is dependent on their biodegradation and release of elements that may or may not incite an adverse reaction. Two main mechanisms have been postulated. The first mechanism is electrochemical reactions wherein the interaction between dental materials and the oral fluids results in structural degradation of the materials causing release of by-products which sets off the adverse reaction. The second mechanism is through mechanical force degradation where masticatory forces induce considerable wear and tear on dental materials which causes release of by-products in the electrolytic oral fluid environment inciting reactions of oral mucosal tissues. There are significant synergisms among electrochemical and mechanical forces.[10]

The management and treatment of oral lichenoid lesions follows the empirical route adopted for oral lichen planus. Steroids form the mainstay in symptomatic lesions. In cases of topographical association with dental materials, removal and replacement with alternatives is advised. Patch tests are usually nonconfirmatory, but it is advisable to utilize them, if available and feasible, to underline a cause-and-effect relationship. In cases of drug associations, discontinuation and replacement of the drug may need medical consultation. It has been frequently observed that in spite of discontinuation of the drug, lesions do not show immediate remission. This has been postulated to the sensitization of the oral mucosal tissues by the offending molecule, which persists as an independent factor even after discontinuation. The treatment of oral lichenoid lesions associated with graft-versus-host disease follows the immunosuppressant route adopted for the main medical condition. Maintenance of proper oral hygiene, removal of accumulated plaque, and use of prophylactic mouth rinses may go a long way in removal of the inciting factors. In view of the high malignant transformation rates for oral lichenoid lesions, regular follow-ups and biopsies need to be taken to monitor the progress of the lesion.[10]

In the differential diagnosis, other lesions in the oral mucosa were considered. In clinical examination, the patient did not have any systemic disease or any lesions in the skin and oral mucosa consistent with oral lichen planus. Therefore, it was thought to be associated with cast metal restorations and amalgam adjacent to the lesion with the support of histopathological evaluation.[11]

   Conclusion Top

It can be concluded that lichenoid lesions of oral mucosa present a diagnostic challenge. It should be distinguished from oral lichen planus, drug-related oral lichenoid reaction, or contact dermatitis based on etiological, clinical, and histological criteria. In general, oral lichenoid reaction resolves once causative agent has been discontinued. However, the timely diagnosis of the lesion is essential, and the provision of a suitable alternative restorative appliance is paramount for a successful oral health of the patient.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Alnazzawi A. Effect of fixed metallic oral appliances on oral health. J Int Soc Prev Community Dent 2018;8:93-8.  Back to cited text no. 1
Minciullo PL, Paolino G, Vacca M, Gangemi S, Nettis E. Unmet diagnostic needs in contact oral mucosal allergies. Clin Mol Allergy 2016;14:10.  Back to cited text no. 2
Thanyavuthi A, Boonchai W, Kasemsarn P. Amalgam contact allergy in oral lichenoid lesions. Dermatitis 2016;27:215-21.  Back to cited text no. 3
Zhang X, Wei LC, Wu B, Yu LY, Wang XP, Liu Y. A comparative analysis of metal allergens associated with dental alloy prostheses and the expression of HLA-DR in gingival tissue. Mol Med Rep 2016;13:91-8.  Back to cited text no. 4
Bishara SE, Barrett RD, Selim MI. Biodegradation of orthodontic appliances. Part II. Changes in the blood level of nickel. Am J Orthod Dentofacial Orthop 1993;103:115-9.  Back to cited text no. 5
Clayton TH, Wilkinson SM, Rawcliffe C, Pollock B, Clark SM. Allergic contact dermatitis in children: should pattern of dermatitis determine referral? A retrospective study of 500 children tested between 1995 and 2004 in one U.K. centre. Br J Dermatol 2006;154:114-7.  Back to cited text no. 6
Imirzalioglu P, Alaaddinoglu E, Yilmaz Z, Oduncuoglu B, Yilmaz B, Rosenstiel S. Influence of recasting different types of dental alloys on gingival fibroblast cytotoxicity. J Prosthet Dent 2012;107:24-33.  Back to cited text no. 7
Dudhia BB, Dudhia SB, Patel PS, Jani YV. Oral lichen planus to oral lichenoid lesions: Evolution or revolution. J Oral Maxillofac Pathol 2015;19:364-70.  Back to cited text no. 8
[PUBMED]  [Full text]  
Sunitha J, Ananthalakshmi R, Sathiya Jeeva S. Oral lichenoid reaction-an overview. IOSR J Dent Med Sci 2016;15:56-8.  Back to cited text no. 9
Kamath VV, Setlur K, Yerlagudda K. Oral lichenoid lesions-a review and update. Indian J Dermatol 2015;60:102.  Back to cited text no. 10
[PUBMED]  [Full text]  
Guvenc MN, Samdanci ET, Akatli AN, Erdogan E, Yolcu U. Lichenoid hypersensitivity reaction against to dental amalgam: Case report. Med Sci 2019;8:466-7.  Back to cited text no. 11


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]


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