Use of Laser Therapy in Amalgam Tattoo Removal

This case report demonstrates the benefits of using a 9300 nm CO2 laser to eliminate this type of lesion.

By Marc Cohn, DDS, Brad J. Wall, DMD, Gregory M. Schuster, DDS, MEd and Rafael Morales, DMD On May 17, 2024

An amalgam tattoo is a benign, iatrogenic, pigmented lesion of the oral cavity. The lesion is typically characterized as a localized blue, gray, or black macule primarily located on the marginal gingiva and occasionally in oral mucosa, including the floor of the mouth.^1,2 It is not elevated and has no texture.^2,3

The lesion is caused by the unintentional implantation of amalgam during the placement or removal of dental amalgam restorations and, to a lesser extent, the trace metals released during the removal of porcelain fused to metal crown restorations.^1-4 Radiographic evidence of opaque particles in the corresponding areas of the clinical pigmentation is virtually pathognomonic of amalgam tattoo.⁵

Amalgam tattoo can be present without radiographic evidence, therefore, in the absence or history of amalgam and/or metallic restorations, a biopsy should be recommended to differentiate between other causes of oral pigmentation.⁵ A differential diagnosis includes melanoma, vascular malformations, and melanocytic nevi.⁶ Once the definitive diagnosis of amalgam tattoo has been established, removal is indicated only for cosmetic concerns.^1,2

The removal of amalgam tattoo historically involved surgical approaches utilizing connective tissue grafting (CTG) and keratinized gingival grafting (KGG).^2,7-10 Mathews¹¹ compared the outcomes of masking the amalgam tattoo with KGG vs amplifying the tissue bed with CTG followed by surface pigment removal by gingivoplasty. In another study, Campbell² used a combination of CTG followed by surface removal of pigmentation with an ErCr:YSGG laser. Several studies have demonstrated successful laser removal of amalgam tattoo using a surgical ablation technique alone.^1,4,12-13 In the following case report, a 9300 nm CO₂ laser was utilized to surgically ablate an amalgam tattoo in a single visit.

Clinical Case and Laser Protocol

A 50-year-old man presented to Midwestern University College of Dental Medicine-Arizona Dental Clinic for a routine dental appointment in May 2022. The patient gave a history of rare and inconsistent tobacco (cigarette) use with no usage in the past 25 years. He also had a history of occasional alcohol consumption and snoring. The patient’s Stop Bang Score was low risk and his overall oral hygiene was good with minimum to low visible plaque levels and no pocket depths greater than 3mm.

The patient reported a 5-year history of an unsightly dark bluish stain on the palatal tissue between tooth #13 and #14 with no history of trauma or bacterial, viral, or fungal infection other than endodontic treatment of tooth #13. Clinical evaluation confirmed the presence of a lesion sized 4 x 5 mm in length and width near the interdental papillae (Figure 1). Periapical radiographs showed a ceramic/metal crown on tooth #14 with a large mesial metallic overhang (Figure 1B), the remainder of an amalgam core build-up.

In the absence of other factors, an assumed clinical diagnosis of an amalgam tattoo was established. Due to the lack of clinical changes and its long-standing history, the provider opted not to biopsy the lesion. Removal of the amalgam tattoo with a CO₂ laser was discussed with the patient who consented to such treatment at the next visit.

A single visit, surgical ablation of the amalgam tattoo was completed on August 18, 2022, with a 9300 nm CO₂ laser using hard and soft tissue settings of 15.6 W (beam spot size at target of 0.012 cm², 15% mist, and 60% cutting speed) and a skin contact application technique for about 60 seconds with 20% benzocaine topical anesthetic.

The amalgam tattoo was ablated in a continuous circular motion at 10 to 14 mm above the tissue surface until all the metallic residue and pigmentation were removed (Figures 2A-C). The amalgam overhang was removed during the process and the patient reported no pain during the procedure (Figure 3). Hemostasis was achieved, and no surgical dressing was applied to the site. Irradiance at the target was 1300 W/cm², fluence (radiant exposure) was 1.94 J/cm², and total radiant energy was 23.3 J.

The patient was seen 3 weeks after initial treatment for a post-op visit. The site was healing well with no signs of inflammation and no reports of pain (Figure 4). Several unrelated appointments occurred over the next 8 months with further improvement in the tissue color and on April 13, 2023, a final post-operative visit demonstrated no reported pain, healthy pink tissue with normal contours, and no periodontal pocket depths > 3 mm (Figure 5).

Discussion

At the time of publication, this is the first known case report of amalgam tattoo removal using a 9300 nm CO₂ laser in a single visit. The surgical technique encompassed complete removal of the gingival discoloration and any metallic shrapnel noticed in the surgical field, including the mesial overhang on tooth #14.

Visualization of the operating field was excellent with 2.5x loupes. No additional magnification was necessary during the procedure. We feel the ability to visualize was primarily due to the coagulation effect, characteristic of this laser’s wavelength, allowing the procedure to be completed in 60 seconds.

This outcome compares favorably with other studies using lasers based on anesthesia used and duration of procedure.^{1,2,4,5,12,13} Campbell and Deas² successfully removed amalgam tattoo using a two-stage surgical technique consisting of CTG followed by gingivoplasty with an ErCr:YSGG laser 2.5 months later. The laser portion of this procedure, however, lasted about 20 minutes and required local anesthetic.

In 2020, Mikami et al⁴ demonstrated complete removal of amalgam tattoo on 18 patients using an Er:YAG laser. In this case, 16 of the 18 patients required local anesthesia and no duration of the laser treatment was reported. In a study most similar in technique to the current report, Yilmaz et al¹ reported a single-stage removal of amalgam tattoo using an ErCr:YSGG laser and topical anesthetic. The length of the surgical procedure was 10 minutes.

In these cases where lasers were utilized as a surgical instrument, minimal post-operative pain was reported. This finding is supported by a randomized clinical trial by Lopez Jornet and Camacho-Alonso¹⁴ in which patients reported minimal pos-operative pain and swelling with CO₂ procedures compared to those with a cold knife.

Conclusion

Amalgam tattoo is encountered by a small percentage of the population and usually does not create a clinical issue once the proper diagnosis has been confirmed. When occurring in the esthetic zone, dentistry can offer a nonsurgical approach to its removal.

References

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