Oral mucosal lesions related to silver amalgam restorations Jolanta Bolewska, DDS,nj b Hans J@gen Hansen, DDS, PhD,a Palle Holmstrup, DDS, PhD, Dr odont,ap bsc Jens J&-gen Pindborg, DDS, Dr odont,“, b and Maja Stangerup, IVD,~ Copenhagen, Denmark UNIVERSITY HOSPITAL AND THE ROYAL DENTAL COLLEGE A total of 49 consecutive patients with lesions of the oral mucosa that were in contact with corroding dental amalgam restorations were subdivided into two groups. In group 1 the lesions were restricted to the contact area opposing the dental restoration, whereas the extent of the lesions in group 2 exceeded that of the contact area. Epicutaneous test for mercury allergy showed that a signficantly greater proportion of the patients in group 1 had positive reactions to mercury than in group 2 @ = 0.019). The amalgam restorations were replaced by composite resin or porcelain fused to gold crowns, or contact between amalgam fillings and oral mucosa was prevented by an acrylic splint. After this treatment regression of lesions was far more pronounced in group 1 than in group 2 @ < 0.001). On the basis of these findings, contact allergy to mercury is suggested as a possible etiologic factor of the mucosal changes in group 1, and the designation contact lesion is proposed for such lesions. The lesions of patients in group 2 seem unrelated to a contact allergy to mercury, and other causes such as lichen planus should be considered. (ORAL SURC ORAL MED ORAL PATHOL 1990;70:55-8)

T

he term galvanic lesion is frequently used to denote whitish, reddish, or whitish-reddish oral mucosal lesions related to metallic dental restorations. The term was introduced in the 1930s to describe superficial electrocoagulations of the mucosa lining.lM3 Electrogalvanic current has been proposed as the causeof the lesions,4-8but neither clinical9 nor experimental studieslo have supported such a hypothesis. Further, oral lichen planus has been discussedas a possible reaction of contact allergy to restorative metals, in particular to mercury released during corrosion of silver amalgam fillings.““5 The frequency of hypersensitivity to mercury in nonselectedpopulation samples has been reported between 4.9%16and 3.2%17but between 16% and 62% in patients with lichen planus. ’ 2-’5 Past reports have not identified the background of

aDepartment of Oral Medicine and Oral Surgery, University Hos-

pital. bDepartment of Oral Pathology and Oral Medicine, The Royal Dental College. CDepartment of Periodontology, The Royal Dental College. dDepartment of Dermatology, University Hospital. 7113111635

lesions related to dental restorations, and, in addition, there are clinical and histologic problems in the differential diagnosis of these lesions and those related to oral lichen planus. The present study addressedthe standing controversy over the cause of oral lesions associated with dental metallic restorations. Its purpose was to clarify whether hypersensitivity reactions are possibly involved in the development of such lesions and whether the lesions reverse after exchange of the fillings. MATERIAL

AND METHODS

A total of 49 patients with combined whitish and reddish, sometimes striated, seldom ulcerated lesions of the oral mucosa that were topographically related to silver amalgam restorations were subdivided into two groups: group 1 consisted of 25 patients, 21 women and 4 men, aged 29 to 74 years (median age: 49 years) and the lesions mentioned above restricted to the contact zone with the amalgam restorations (Fig. 1); group 2 consisted of 24 patients, 12 women and 12 men, aged 32 to 74 years (median age: 52 years) with the lesions mentioned above both in the contact zone with amalgam restorations and in areas exceeding the contact zone (Fig. 2). 55

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ORAL SURCORAL MED ORAL PATHOL July 1990

Table I. Cutaneous patch tests performed in patients with mucosal lesions related to silver amalgam restorations (weight/weight) 1. 2. 3. 4. 5. 6.

Mercury chloride 0.05% Zinc chloride 2% Silver nitrate 2% Stannic chloride 10% Copper sulphate 5% Gold chloride 1%

Table II. Symptoms among patients with mucosal lesions related to silver amalgam restorations No Group

symptoms

Tenderness

Pain

1 2

62% 50%

24% 33%

8% 17%

Symptoms, tobacco habits, and the results of cutaneous patch test (Table I) were recorded. The cutaneous patch test was performed in 21 patients from group 1 and in 20 patients from group 2. Metallographic examination of removed amalgam fillings was performed in 13 caseschosen at random among the removed fillings. The treatment of patients from both groups involved elimination of silver amalgam fillings or prevention of contact between oral mucosa and filling by means of acrylic splints. The initial procedure included replacement of 22 silver amalgam fillings in 12 patients with amalgam without gamma-two, but lack of response necessitated a change of the procedure. Thereafter, the silver amalgam fillings were replaced by composite resin or porcelain fused to gold if necessary. Consequently the patients who had been initially treated with nongamma 2 amalgam fillings had a second treatment performed. In group 1,58 amalgam fillings in 17 patients were replaced with composite resin, eight amalgam fillings in four patients were replaced with porcelain fused to gold crowns, and five teeth in five patients were extracted because of advanced periodontitis. In one patient two amalgam fillings were replaced with composite resin and procelain fused to gold crown, respectively. In group 2, 16 amalgam fillings in nine patients were replaced with composite resin, In two patients contact between amalgam filling and oral mucosawas prevented by an acrylic splint covering the amalgam fillings, and in nine patients no treatment was performed becauseof lack of interest.

The responsesto treatment were recorded on the basis of pretreatment and posttreatment photographs taken with a Hasselblad camera (Hasselblad, GMeborg, Sweden) with a 150 mm lens, extension tubes, and ringflash with Agfachrome film. The response was registered as total regression if the lesion was no longer present and marked regression if a lesion was present but 2/ or more of the originally affected area was no longer affected. A regression was registered as minor if 2/ or more of the originally affected area was still affected after exchange of the filling. The patients were reexamined Yz, 1, 2, 3, and 6 months after treatment. RESULTS Symptoms

It appears from Table II that only a small percentage of the patients had pain from the lesions, whereas a higher percentage of patients in both groups experienced tenderness. Tobacco

habits

There was no difference in the prevalence of tobacco smoking between the two groups since smokers made up 48% of group 1 and 46% of group 2. Cutaneous

patch

test

Cutaneous patch test result was positive for mercury chloride in 11 patients (52%) from group 1 and in one patient from group 2 (5%). The difference in positive patch test for mercury between groups 1 and 2 was regarded as statistically significant (Fisher’s exact test: p = 0.019). Eleven of 12 patients (92%) from both groups with positive patch test results to mercury were women, and mercury was the only component of silver amalgam that produced positive patch test results. Metallographic

examination

Among the 13 removed amalgam fillings, 12 were found to be conventional and one nongamma 2 amalgam. All fillings showed severe corrosion. Response

to treatment

Group 1. Twenty-four out of 25 lesions in group 1 showedeither a total or a marked regression, and only one patient showed a minor regression of the lesion. The regression was already visible after 2 weeks in most patients and continued to improve until a stationary result was obtained after 2 months in most cases.There was no recurrence of lesions within the period of observation (Fig. 3). Group 2. All of the lesions of patients in group 2 showed the presenceof white striae, not a prominent

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Oral mucosal lesions related to silver amalgam restorations

57

Fig. 1. Group 1 patient with white lesion of buccal mucosain contact with silver amalgam filling in lower left first molar.

Fig. 3. The patient demonstrated in Fig. 1, 1 year after replacement of silver amalgam with composite resin. The lesion showed total regression,

Fig. 2. Group 2 patient with striated white buccal mucosal lesion, part of which is in contact with a silver amalgam filling in lower left second molar.

Fig. 4. The patient in Fig. 2,6 months after replacement of silver amalgam filling with composite resin. There is no regression.

feature of lesions of patients in group 1. In group 2 only one of the 11 treated lesions showed a marked regression, and eight patients responded with minor regression. The difference in response to treatment was statistically significant (Fisher’s exact test: p < 0.001).

DISCUSSION

In the present study we have classified patients with mucosal lesions related to silver amalgam restorations into two groups on the basis of the extent of the lesions. Group 1 comprised patients with lesions restricted to the contact area with the amalgam res-

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torations, whereas group 2 comprised patients with lesions both in contact with amalgam restorations and outside the contact area. The positive responseto exchange of amalgam fillings among group 1 patients implicates the surface of the fillings or substanceseither on or releasedfrom the surface of the fillings. The many positive patch test results for mercury among group 1 patients favors the possibility that mercury released from the surface of the fillings is involved in the pathogenesis of at least some of the group 1 lesions, since mercury was the only component of silver amalgam that produced positive patch test results among the examined patients. The inconsistent reactions among group 1 patients may be due to lack of total correction between hypersensitivity of the oral mucosa and those of the skin.” It also may be due to different causative factors of the lesions. The lack of responseto the exchange of fillings in group 2 patients (Fig. 4) decreasesthe likelihood that the fillings are involved in the etiology of these lesions. In addition, only one of the group 2 patients had a positive patch test result for mercury. The presenceof white striae as a characteristic feature of theselesions, however, indicates that they might instead be lesions of oral lichen planus. If so, the present results do not support the findings mentioned above of a correlation between oral lichen planus and contact hypersensitivity to mercury. The patch test for mercury had positive results in 5% of group 2 patients, which is a frequency similar to that in the general population.15,I6 In conclusion, lesions of the oral mucosa confined to the contact area with dental silver amalgam fillings may be caused by a contact allergy reaction to mercury released from the silver amalgam and could be denoted contact lesions. Evidence of such a hypothesis for lesions of the oral mucosa exceeding the contact area has not been found, and other causessuch as oral lichen planus should be considered.

ORAL SURG ORAL

PATHOL July 1990

MED ORAL

REFERENCES

Lain ES. Chemical and electrolytic lesionsof the mouth caused by artificial dentures. Arch Dermatol Syphilol 1932;25:21-31. Hollander L. Galvanic burns of the oral mucosa. JAMA 1932;99:383-4. Hollander L, Shonheld L, Fisher A. Galvanic burns of the tongue. JAMA 1933;100:1029-33. Bandczy J, Roed-Petersen B, Pindborg JJ, Inovay J. Clinical and histologic studies on electrogalvanically induced oral white lesions. ORAL SURG ORAL MED ORAL PATHOLI979;55:60-1. 5. Holland R. Galvanic currents between gold and amalgam. Stand J Dent Res 1980;88:269-72. 6. Nilner K, Glantz P-O, Ryge G, Sundberg H. Oral galvanic action after treatment with extensive metallic restorations. Acta Odontol Stand 1982;40:381-8. 7. Lind PO, Hurlen P, Koppang HS. Electrogalvanically induced contactallergyoftheoralmucosa. IntJOralSurg1984;13:33945. 8. Syrjanen S, Syrjanen K. Assessmentof oral mucosal changes in patients treated with different metallic restorations and protheses. J Dent 1985;13:244-54. 9. Knychalska-Karwan Z. Przyczynk do roli pradow elektrogalwanicznych w leukoplaki jamy ustnej. Czasopismo Stomatil 1966;19:10-15. 10. Phillips RW, Schnell RJ, Shafer WG. Failure of galvanic current to produce leukoplakia in rats. J Dent Res 1968;47:666. II. Holmstrup P, Sdborg M. Cellular hypersensitivity to oral lichen planus affections in vitro. Acta Allergol 1977;32:304-15. 12. Finne K, Giiransson K, Winckler L. Oral lichen planus and contact allergy to mercury. Int J Surg 1982;I 1:236-9. 13. Eversole LM, Ringer M. The role of dental restorative metals in the pathogenesis of oral lichen planus. ORAL SURGORAL MED ORAL PATHOL1984;57:383-7. 14. Lundstrom IMC. Allergy and corrosion of dental materials in patients with oral lichen planus. Int J Oral Surg 1984;13:1624. 15. Mobacken H, Hersle K, Sloberg K, Thilander H. Oral lichen planus: hypersensitivity to dental restoration material. Contact Dermatitis 1984;10:11-5. 16. Fregert S, Hjort N. Increasing incidence of mercury sensitivity. The possible role of organic mercury compounds,Contact Dermatitis Newsletter 1967;5:236-9. 17. Eversole LM. Allergic stomatitis. J Oral Med 1979;34:93-102. Reprint requests to.

Dr. Jolanta Bolewska Department of Oral Medicine and Oral Surgery University Hospital Tagensvej 20 2200 Copenhagen N, Denmark

Oral mucosal lesions related to silver amalgam restorations.

A total of 49 consecutive patients with lesions of the oral mucosa that were in contact with corroding dental amalgam restorations were subdivided int...
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