Removal of Oral Lichen Planus by CO 2 Laser

Oral lichen planus is a chronic mucocutaneous disease that affects 2% of the population with a 3:1 female-to-male ratio. It is characterized by the presence of erosive lesions, bullous, papular, reticular or white patches on the oral mucosa. The mucosa and the lateral border of the tongue are the most commonly affected areas. There are reports of its association with lesions in the nails, scalp and other areas of mucosa such as on esophagus and vagina. The lesions are painless in most cases, and therefore go unnoticed (1). Lichen planus is a disease of unknown etiology. However, it is a condition in which immune T cells are accumulated on the epithelium of the oral mucosa due to an increasing rate of differentiation in the stratified squamous epithelium, resulting in hyperkeratosis, with or without ulceration. Histologically, the diagnosis is based on the infiltration of mononuclear cells on the surface of the lamina propria, leading to the degeneration Removal of Oral Lichen Planus by CO2 Laser


INTRODUCTION
Oral lichen planus is a chronic mucocutaneous disease that affects 2% of the population with a 3:1 female-to-male ratio.It is characterized by the presence of erosive lesions, bullous, papular, reticular or white patches on the oral mucosa.The mucosa and the lateral border of the tongue are the most commonly affected areas.There are reports of its association with lesions in the nails, scalp and other areas of mucosa such as on esophagus and vagina.The lesions are painless in most cases, and therefore go unnoticed (1).
Lichen planus is a disease of unknown etiology.However, it is a condition in which immune T cells are accumulated on the epithelium of the oral mucosa due to an increasing rate of differentiation in the stratified squamous epithelium, resulting in hyperkeratosis, with or without ulceration.Histologically, the diagnosis is based on the infiltration of mononuclear cells on the surface of the lamina propria, leading to the degeneration

Removal of Oral Lichen Planus by CO 2 Laser
of epithelial cells.The risk of malignant transformation remains controversial (2).
Different forms of treatment have been used to manage the lichen planus.Most treatments are conservative, with the use of topical or systemic drugs that may exacerbate the pain or burning after treatment.Conventional treatment involves the use of antifungal drugs, corticosteroids, triamcinolone, cyclosporine and metronidazole.Surgical treatment is not conventional, but high-power laser has been successfully used in the treatment of leukoplakia and premalignant lesions (3).In addition, the excimer laser has been used in biostimulation of oral lichen planus, with a photochemical effect that causes regression of the lesion (4,5).
The tissue effect of CO 2 laser is mainly produced by heat generation.This heat may result in an increase in temperature that carbonizes and vaporizes the irradiated tissues.Its action on the tissue is produced in two stages.First, the optical energy is converted into energy of vibration of the molecules that absorb radiation.
In a second step the energy becomes the translation, which is accompanied by an increase in temperature and consequently its chemical decomposition.Laser wounds have a small contraction of the tissue repair when compared with wounds made with a scalpel.This contraction occurs mainly in excisions, with considerable tissue loss and its goal is to approximate the edges of the wound, however, this may result in scarring.This phenomenon is due to considerable decrease or absence of myofibroblasts, which are fibroblasts with features of smooth muscle cells.In addition, hemostasis, reduced scar formation, and immediate sterilization of surgical wounds are other benefits of the CO 2 laser (6,7).
There are only 2 reports in the literature of the use of CO 2 laser for the removal of oral lichen planus in patients who received conventional therapy that was followed by recurrence of the condition.This article reports a case of oral lichen planus removed by CO 2 laser.

CASE REPORT
A 46 year-old female was referred to the Laser Clinic of the Dental School of the Federal University of Bahia, Brazil, with white patches on the oral mucosa (Fig. 1) and complaining of pain and burning sensation.There was a conclusive histopathological diagnosis of oral lichen planus (Fig. 2) by the Laboratory of Surgical Pathology of the same institution.The lesion had been previously treated unsuccessfully with triamcinolone and corticosteroids for 3 months.The patient reported soreness and burning sensation when eating and that the lesions appeared 2 years before consultation.A detailed   clinical interview was carried out during which the patient revealed to be under hypertensive medication (Captopril, 25 mg, once a day).No lesions were observed in the extraoral examination.A preoperative evaluation comprised complete blood count, coagulation profile, fasting glucose and urine analysis.
The surgical procedure was carried out at the Oral Maxillofacial Surgery Clinic of the same institution with a CO 2 Laser (Sharplan 20 C; Laser Industries, Tel Aviv, Israel; λ= 10,600 nm, ϕ=2 mm, CW/RSP, power output used was 10 W).All safety measures were observed during the surgical procedures.The beam was used focused to delimit and vaporize the lesion (Fig. 3A).At the end of the surgery, the beam was used on a defocused mode to promote better hemostasis (Fig. 3B).Neither sutures nor dressings were used following the surgery.The patient received standard orientation for the postoperative period.The patient received a prescription of paracetamol (100 mg, twice a day) and nimesulide (100 mg, twice a day) during 3 days.Mouthwashes (0.12% chlorhexidine) were prescribed for the postoperative period, which was uneventful, except for mild discomfort caused by the removal of the epithelial lining.According to Van der Hem et al. ( 2) reepithelization occurs within 3 weeks after removal of the epithelium by the laser, and the feeling of discomfort when in contact with food or liquid disappears after that.The patient was reexamined after 1 week (Fig. 4) and 1 year after surgery with no signs of recurrence (Fig. 5).

DISCUSSION
A medium output power was used in the present case.The use of small output power has been shown to cause less damage and be effective on the removal of oral mucosal lesions.The less the thermal damage the better the repair.Another aspect that needs clarification is the technique used for removal of the lesion.The choice for vaporization was due to the fact that the lesion had been biopsied before.
The most interesting features of the CO 2 laser surgery are local hemostasis, cauterization of nerve endings and sealing of lymphatic vessels.In addition, the very high temperatures generated by the laser beam on the tissue sterilizes the wound surface, reduces the risk of postsurgical infection and avoids the use of antibiotic therapy.We prescribed no antibiotic to any of the patients and none showed signs of local infection on follow up time.We observed that no patient complained of pain or showed signs of infection on the post-operative period.The cauterization of the nerve endings is important as it causes the formation of thermal neuromas at the ending of the nerve causing less pain after surgery and reducing  the use of painkillers.Additionally, scar formation is minimized due to the sparse presence of myofibroblasts.This late feature is very important on the treatment of oral lesions especially on areas in which scar tissue may cause impairment of the function.It has been shown that the amount of myofibroblasts on CO 2 laser wound is 3 times less than that the found on scalpel wounds.In these procedures nor sutures nor dressings are used and the healing occurs by second intention.The use laser surgery has increased largely over the last 10 years.However, the cost of the equipment and need for qualification on surgical specialties have limited the access of dentists to its benefits.The correct indication of this surgical technique is both cost effective and reliable on the treatment of oral lesions, including premalignant ones.The use of CO 2 laser does not reduce the risk of relapses of the lesion, but it is an easy technique to use and results on both fast surgical procedure and silent postoperative period.Furthermore, it may be safely used on the dental practice (7).
In this article, we presented a case that relapsed after conventional therapy.It is known that this lesion may affect any region of the oral cavity, being the oral mucosa, tongue and gingiva the most commonly affected areas.Lesions on the palate are less frequent (7)(8)(9), occurring mainly in adults and being rarely found in children (1).A study of 200 cases showed a strong predominance in females aged between 40 and 70 years (8).In the present case, the patient had a large lesion extending from near the maxillary second molar to the lip commissure.Histologically, the case fulfilled the morphological criteria for oral lichen planus as previously reported (7)(8)(9)(10).
The option for surgery was due to the lesion extension and the fact that it was impairing the patient's working activities.The literature presents surgical and nonsurgical treatments, depending on lesion type and extension and the patient's systemic condition (10)(11)(12)(13)(14).Each laser has a specific wavelength.Due to its wavelength, the CO 2 laser has very strong affinity for soft tissues besuase of their high fluid contents, and it is an optimal tool for removing superficial skin and mucosal lesions (14)(15)(16)(17).
Loh (6) used CO 2 laser in 10 patients for removing tumors, showing that lichen planus did not reappear in areas hit by the laser.In the present case study, the follow up of 1 year showed no recurrence and disappearance of the burning sensation and pain.Van der Hem et al.
(2) used CO 2 laser in 21 patients after treatment with of steroids.Also, prior to surgery, those patients had indication of painful burn sensation.Laser treatment removed the lesion leaving a safety margin of 2 mm beyond the lesion and follow up indicated no more pain.
It is concluded that the use of the CO 2 laser is useful and effective in the treatment of oral lichen planus.

Figure 1 .
Figure 1.Preoperative clinical aspect of the lesion on the oral mucous.

Figure 2 .
Figure 2. Histopathological aspect confirming the diagnosis of oral lichen planus.

Figure 3 .
Figure 3. Immediate aspect following CO 2 laser removal.A= Aspect of the area after vaporization of the lesion (laser on focused mode); B = Aspect of the area after use of the laser on the defocused mode to improve hemostasis.

Figure 4 .
Figure 4. Clinical aspect of the area 1 week after CO 2 laser surgery.

Figure 5 .
Figure 5. Clinical aspect of the area 1 year after CO 2 laser surgery.