Phototherapy approaches in treatment of oral lichen planus
- Conflicts of interest:
- None declared.
Oral lichen planus (OLP) is a chronic immunologic mucocutaneous inflammatory disease of the oral mucosa. Since the etiopathology of OLP is idiopathic, treatment is usually symptomatic, therefore showing low predictability. Currently, topical corticosteroids are widely accepted as the standard therapy. However, for patients unresponsive to standard therapy for OLP, new treatment modalities have been sought. Phototherapy has recently been accepted as an alternative or adjunctive treatment modality for many conditions in medicine and dentistry. The aim of this study is to present the advantages and disadvantages of the different kinds of phototherapy used in treatment of OLP (UV phototherapy, lasers, and photodynamic therapy). The main outcome measures compared were improvement of signs and symptoms and OLP recurrence. Although some phototherapy techniques in the selected articles have demonstrated limited effects, there is no solid basis in evidence for the effectiveness of any of these treatments for OLP. Therefore, further research, especially randomized controlled clinical trials with long-term follow-up, is needed to give any solid recommendation on the use of phototherapy in the field of OLP treatment.
Oral lichen planus (OLP) is a chronic immunologic mucocutaneous inflammatory disease of the oral mucosa that affects 0.2–3% of the population [1, 2]. It most commonly affects people in the fourth decade of life, with a 1.4 : 1 female-to-male ratio of incidence . Clinically, we can identify reticular/hyperkeratotic, papular, erosive/ulcerative, plaque-like, atrophic, and bullous types . The most common form is reticular OLP, characterized by white lacy streaks known as Wickham's striae, which are generally surrounded by discrete erythematous borders . Intraorally, the most commonly affected areas are the posterior buccal mucosa, the lateral border of the tongue, and the gingiva, but other sites may also occasionally be affected, particularly the palate, lip, and floor of the mouth . Oral mucosal lesions can occur independently, but are combined with skin lesions in 60–70% of patients; these are usually located at ankles, wrist, nails, scalp, or genitalia . The lesions are, in most cases, painless, and therefore go unnoticed. Only the atrophic, erosive, and bullous forms may be associated with symptoms, ranging from a mild burning sensation to severe pain affecting normal masticatory function . Some authors classify OLP as a premalignant condition , suggesting that longstanding and nonhealing erosive lesions could potentially transform into squamous cell carcinoma (in 0.4–2% of patients over a 5-year observation period). Oral biopsy with histopathological examination is recommended to confirm the clinical diagnosis and to exclude possible dysplasia and malignancy .
The etiology of OLP is unknown in most cases [1-5]. It is considered to be a T-lymphocyte-mediated immunological disorder. Many authors have suggested that a combination of specific and nonspecific mechanisms may be involved in the etiopathogenesis of this condition. This theory may explain the aggregation of T lymphocytes in the oral mucosal epithelium due to enhanced differentiation in the stratified squamous epithelium, resulting in hyperkeratosis and erythema with or without ulceration [3-5]. High stress and anxiety levels and drug reactions are proven to be associated with lichen planus [6, 7], while the association with hepatitis C virus infection is still debated .
To date, various treatment modalities have been introduced, but given that OLP's etiopathology cannot be established, treatment is usually symptomatic, therefore showing low predictability [3-5]. Most treatments are conservative/pharmacological, such as corticosteroids (e.g. triamcinolone), retinoids or retinoid analogues (e.g. etrenitate, temarotene), immunosuppressants (e.g. tacrolimus), or immunomodulatory agents (e.g. cyclosporine). Among them, topical corticosteroids are widely accepted as the primary treatment of choice [3-5]. One of the main drawbacks of topical corticosteroids is that long-term application can be hard to apply on the oral mucosa, causing frequent relapses upon the treatment's discontinuation. Also, their use may lead to development of secondary candidiasis that needs to be treated  or tachyphylaxis . Even though they are widely accepted, conservative/pharmacological therapeutics are often disappointing and palliative, and recurrences of the lesions are common even after the therapy is ceased [3-5]. The need for better treatment alternatives is obvious, especially for patients unresponsive to standard therapy for OLP. Phototherapy (light therapy, heliotherapy) has been widely used as an alternative or supplementary treatment modality, and it has numerous applications in modern medicine and dentistry. The aim of this study is to give a systematic overview of the effects of different types of phototherapy used for treatment of patients with OLP, describing their advantages and disadvantages and pointing out potential gains and risks of each.
Materials and methods
Studies published up to June 2013 were obtained from the Medline/PubMed, ScienceDirect, and Cochrane Library of the Cochrane Collaboration (CENTRAL) online databases, using the following search terms: ‘UV radiation’ AND ‘oral lichen planus’, ‘laser therapy’ AND ‘oral lichen planus’, ‘lasers’ AND ‘oral lichen planus’, ‘photodynamic therapy’ AND ‘oral lichen planus’, ‘phototherapy’ AND ‘oral lichen planus’, ‘PUVA’ AND ‘oral lichen planus’. Screening and study selecting was performed independently by each author (V. P. and V. V.-A.) to avoid the potential for reviewer bias. Further, the references of all selected articles were scanned. The corresponding authors were contacted in cases of the data originally reported in the studies being missing or insufficient. The online database search initially identified 302 publications. On the basis of title and abstract evaluation, the authors agreed by discussion to exclude 257 publications. The remaining 45 publications in full-text format (relevant or possibly relevant) were retrieved for more detailed analysis.
Study inclusion and exclusion criteria
Selected publications were further analyzed according to the following inclusion criteria:
- Publication in an international peer-reviewed journal
- Publication in the English language
- Treatment of clinically and biopsy-proven OLP (WHO diagnostic criteria) that was unresponsive to conventional therapy
- Presence of at least 5 patients in the test and control groups
- Human adult subjects (age ≥ 18 years)
Studies that fulfilled the inclusion criteria were further analyzed according to the following exclusion criteria:
- Insufficient information on phototherapy parameter settings
- No outcome of interest
- Being a duplicate study
A total of 15 selected studies met the required selection criteria. Selected studies were subdivided into three groups according to phototherapy approach: UV phototherapy, 3 articles; lasers, 8 articles; and photodynamic therapy, 4 articles. Main outcomes, such as improvement of signs (inflammation, erythema, reticulation, ulceration), improvement of symptoms (pain, discomfort), and recurrence, were measured.
The present review attempts to systematically evaluate the available literature on phototherapy approaches to treatment of OLP. At the same time, it should be mentioned that due to the extreme heterogeneity of the selected studies (in study design, phototherapy wavelengths, phototherapy device parameters, observation period, etc.), a meta-analysis could not be performed.
After establishing the scores for quality assessment (Table 1), an overall estimation of risk of bias (low, all criteria met; moderate, one or more criteria partly met; high, one or more criteria not met) was determined for each selected study (Table 2) according to the Cochrane Handbook for Systematic Reviews of Interventions, Version 5.0.2 (http://www.cochrane-handbook.org/). Quality assessments of all selected studies were performed independently by each author (V. P. and V. V.-A.).
Table 1. Categories used to assess the quality of selected studies
|A||Calculation of sample size (minimal number of participants necessary in order to achieve a statistically significant difference among compared groups)||0 = not mentioned|
|1 = reported, but not confirmed|
|2 = reported and confirmed|
|B||Randomization and allocation concealment methods||0 = clearly inadequate|
|1 = possibly adequate|
|2 = clearly adequate|
|C||Clear definition of inclusion and/or exclusion criteria||0 = no|
|1 = yes|
|D||Completeness of follow-up||0 = no|
|1 = yes|
|E||Experimental and control group comparable at study baseline||0 = no|
|1 = unclear|
|2 = clearly adequate|
|F||Presence of masking||0 = no|
|1 = unclear|
|2 = yes|
|G||Appropriate statistical analysis||0 = no|
|1 = unclear|
|2 = yes|
Table 2. Quality assessment of the selected studies
|Lundquist et al. ||0||0||1||1||0||0||2||High|
|Sharma et al. ||0||0||1||1||2||1||1||High|
|Kassem et al. ||0||0||1||1||0||1||2||High|
|Van der Hem et al. ||0||0||1||1||0||0||1||High|
|White et al. ||0||0||0||1||0||0||2||High|
|Horch et al. ||0||0||1||1||0||1||2||High|
|Cafaro et al. ||0||0||1||1||0||0||2||High|
|Cafaro et al. ||0||0||1||1||0||0||2||High|
|Köllner et al. ||0||0||0||1||0||2||2||High|
|Trehan et al. ||0||0||1||1||0||0||2||High|
|Aghahosseini et al. ||0||0||1||1||0||1||2||High|
|Sadaksharam et al. ||0||0||1||1||0||1||2||High|
|Sobaniec et al. ||0||0||0||1||0||1||2||High|
|Kvaal et al. ||0||0||1||1||2||0||2||High|
Long-wave UVA light (wavelength 315–400 nm) is present in sunlight. UVA treatment usually comprises UVA radiation combined with a sensitizer (a chemical that increases the effect of UVA) called a psoralen. This form of treatment is referred to as PUVA (psoralen + UVA). Regarding PUVA, it has been confirmed that orally administered 8-methoxypsoralen (8-MOP) followed by administration of UVA radiation intraorally to the affected sites can successfully treat longstanding and severe OLP and oral lichenoid lesions [11, 12]. Additionally, photochemotherapy with solar radiation (PUVASOL) has been introduced as an effective and cheaper alternative to PUVA . A comparative study by Sharma et al. demonstrated that PUVASOL can be used as an alternative therapy for OLP that is equally effective as or more effective than conventional OLP therapies . Even though several authors suggest that UVA radiation is safe and effective for use in treatment of OLP (Table 3), they simultaneously report many common short-term side effects of UVA phototherapy, such as nausea, itching, redness of the skin, ocular risks, dizziness secondary to psoralen, and 24-hour photosensitivity when psoralen is taken orally. Further, the safety of PUVA has not been established during pregnancy and breastfeeding. Gonzalez et al. suggested that some patients might develop an exacerbation of their disease due to PUVA . Also, since PUVA is always administered over wide surfaces of skin, dosimetry can be difficult . However, the biggest concern related to PUVA is its long-term side effects. It has a well-established potential for photocarcinogenicity, carrying a risk of dose- and time-dependent increase in the incidence of squamous cell carcinomas, basal cell carcinomas (nonmelanoma skin cancers), and melanomas [11, 14], especially in Caucasian skin (lighter phototypes). A possible explanation for PUVA photocarcinogenicity could be that it exerts an immunosuppressive effect in addition to its mutagenicity, which causes further cellular damage and is already well documented in in vivo and clinical studies . The documented instances of photocarcinogenicity were on the skin, whereas PUVA's effect on oral mucous membrane is yet to be determined. Nevertheless, special consideration needs to be given to safety issues with PUVA therapy, as it could promote malignant transformation of OLP, which is considered an already premalignant condition . Even though PUVA carcinogenicity can be partly avoided by attentive patient selection and use of synergistic therapies, this treatment approach should only be used when the beneficial effects significantly outweigh the undesirable downsides. The classification of PUVA as a carcinogen is the reason that this phototherapy approach has been discontinued over the past decade and replaced by other treatment modalities with fewer reported side effects.
Table 3. Effects of UV phototherapy on oral lichen planus
|Lundquist et al. 1995 ||8-methoxypsoralen||UVA||18||12 months||PUVA was effective in treatment of OLP and should be used in severe cases|
|Sharma et al. 2003 ||8-methoxypsoralen||UVA + solar radiation||75||12 weeks||PUVASOL was effective as standard therapy (topical corticosteroids) with no side effects|
|Kassem et al. 2012 ||None||UVB||14||8 weeks||Local UVB phototherapy may be a promising treatment modality for erosive OLP|
UVB light (wavelength 290–315 nm) is present in natural sunlight. UVB treatment consists of two types: broadband UVB and narrowband UVB (NB-UVB), which are in many ways similar, except that narrowband UVB lightbulbs (UVB narrowband lamps) release a smaller range of ultraviolet light (311–313 nm) than broadband UVB sources. Since NB-UVB appears to be equally effective as or even more effective than broadband UVB with fewer reported adverse effects, it is increasingly used and has almost totally replaced broadband UVB. Further, comparative studies have revealed that while NB-UVB is similarly efficient to PUVA, it is certainly more convenient to use and probably less carcinogenic than PUVA [16, 17]. Since the efficacy of NB-UVB has been demonstrated in the treatment of atopic dermatitis, localized scleroderma, urticaria pigmentosa, cutaneous lichen planus, and severe psoriasis [16-18], it was reasonable to expect that it would be equally efficient in OLP therapy. Regarding UVB phototherapy for treatment of OLP, only one study met the selection criteria for this review . In this study, 14 patients were treated by local UVB therapy (TheraLight UV 120-2 system; TheraLight Inc, Carlsbad, CA, USA). Complete reduction of the lesions in the affected mucosal area was achieved in 64.3% of patients, and the other 35.7% demonstrated partial response within 8 weeks, without any serious side effects . The authors suggested, within the limitations of their study, the use of local UVB phototherapy as a promising treatment modality for OLP (Table 3).
The use of lasers has been proven to be advantageous in comparison with conventional therapy for numerous applications in dentistry, but unfortunately, the cost of laser equipment and the need for laser-qualified personnel have limited the access of dentists to laser benefits. The benefits of laser therapy include successful ablation and vaporization, hemostasis, disinfection, decontamination, and minimal pain and swelling after surgery [19-21]. When lasers are used correctly, they are a fast, reliable, and cost-effective treatment approach, with, most importantly, high patient tolerance . It is not recommended as the first choice for OLP treatment, but it is suggested for use with patients whose condition causes spontaneous pain, burning, and bleeding and who are unresponsive to topical corticosteroids . It is suggested that lasers could be used in high- and low-level laser irradiation modes for efficient treatment of OLP with no visible side effects (Table 4). High-level laser irradiation is used for successful OLP tissue ablation (removing as much necrotic tissue as possible). Advances in laser technology have provided systems for site-specific delivery of laser energy with short-interaction items on tissue to be ablated . The selected studies confirmed the usefulness and effectiveness of CO2 laser ablation in removing OLP lesions [22-25]. All authors agreed that removal of the lesions using the laser was fast and easy, with no need for suturing. The healing process was fast and uneventful, with minimal postoperative discomfort, minimal pain, swelling, and bleeding, and no visible scarring. Also, a rapid disappearance of symptoms was reported, with immediate relief in all patients of associated burning sensations and the return of tolerance to hot and spicy foods, and with only minor discomfort during and after the intervention [22-25]. CO2 lasers were thus proven to be effective in the immediate relief of symptoms and to contribute to the clinical improvement of OLP (Table 4), further suggesting an effective opportunity to prevent malignant transformation of the lesions [22-25]. However, special attention should be given when lasers are used in an ablative manner, since laser-removed lesions cannot be properly histopathologically evaluated , and sometimes oral surgery procedures can cause irritation that triggers the formation of new lesions, presumably associated with Köbner's phenomenon, and recurrence of the inflammatory condition .
Table 4. Effects of various laser systems in therapy of oral lichen planus
|Van der Hem et al. 2008 ||CO2 laser (10 600 nm), continuous||21||Long term remission of OLP lesions|
|White et al. 1998 ||CO2 laser (10 600 nm), Nd:YAG laser (1064 nm)||64||Minimal postoperative pain, elimination of need for sutures after ablation|
|Horch et al. 1986 ||CO2 laser (10 600 nm), continuous||7||Minimal pain during postsurgical period; healing occurred without contractions|
|Loh 1992 ||CO2 laser (10 600 nm), continuous||10||Immediate pain relief, faster healing with no swelling or bleeding|
|Cafaro et al. 2010 ||LLLT with Ga-As diode laser (904 nm), pulsed||13||Significant reduction in pain and inflammation, great enhancement in the patient's quality of life|
|Cafaro et al. 2013 ||LLLT with Ga-Al-As diode laser (980 nm), pulsed||30||Significant reduction in clinical scores of the treated lesions and in reported pain; no side effects|
|Köllner et al. 2003 ||UVB excimer laser (308 nm)||8||Overall improvement in the clinical outcome|
|Trehan et al. 2004 ||UVB excimer laser (308 nm)||8||Faster wound healing with no pain, swelling, or burning sensations|
Low-level laser therapy
Low-level laser therapy (LLLT; photobiostimulation, photobiomodulation) has biostimulatory effects, such as increasing of cell metabolism and/or tissue regeneration and potential tissue healing, without side effects . Furthermore, LLLT has anti-inflammatory effects on target tissues and cells and has been proven to reduce pain caused by various etiologies . Because of the immediate pain relief it produces, LLLT has been suggested as a possible treatment for oral erosive lesions [30-34]. For this review, two studies reporting the effects of LLLT on OLP were selected (Table 4). Both studies [32, 33] employed low-level diode laser irradiation (904 and 980 nm, respectively). OLP lesions were located in gingiva, tongue, buccal mucosa, and palate. LLLT was delivered with a probe held perpendicularly at a distance of 2 mm above the tissues (noncontact mode) and at a fluence of 4 J/cm2. The studies demonstrated significant improvement in visual analogue scale pain score and clinical parameters of inflammation (assessed by Thongprasom sign scoring), as well as stability of results in the follow-up period, with no complications and/or therapy side effects reported. The number of laser sessions needed for OLP lesion healing varied according to lesion characteristics, namely localization. In most of the reported cases clinical remission was obtained within 5–6 weeks. The low-level Ga-Al-As diode laser (980 nm) has more superficial action than the Ga-As laser (904 nm), which may be a possible explanation for the better treatment outcome when the Ga-Al-As laser was used. Jajarm et al. demonstrated the comparable usefulness of low-level diode laser irradiation (630 nm) and the conventional treatment (topical corticosteroids in the form of dexamethasone mouthwash) immediately after the treatment of OLP and during the follow-up period .
Persisting controversies regarding the photobiomodulation effect of LLLT on tissues/cells and the nonhomogeneity of the data reported make an interpretation of LLLT benefits particularly difficult. In order to determine the most efficacious way to use laser therapy (the optimal set of laser irradiation parameters, treatment intervals with well-defined duration and frequency), further carefully designed clinical studies with a larger number of patients and a prolonged follow-up period are necessary. Also, the big concern related to oral use of lasers would be the optimal design of the application handpiece (designs for different spot sizes, various shapes for better handling, etc.).
The excimer laser
The excimer laser emits a high-intensity beam of UVB light. The 311-nm NB-UVB excimer laser has proved to be a highly successful treatment option for cutaneous lichen planus [35-37]. It has been suggested that the 311-nm excimer laser should produce positive results in OLP, but until now there were no good delivery systems for using this radiation intraorally. The 308-nm NB-UVB excimer laser has recently been confirmed as a successful treatment option for plaque-type psoriasis, vitiligo, and other papulosquamous dermatoses . Two studies regarding the use of the 308-nm UVB excimer laser in therapy for OLP met the criteria for this review [36, 37]. In the selected studies, 308-nm UVB lasers were applied using a flexible delivery system with spot size allowing irradiation to be limited to specific lesions while sparing surrounding healthy tissue from unnecessary UVB exposure. Authors agreed that the high output energy makes this type of laser therapy relatively fast to perform. Laser irradiation was performed at quite low starting/initial doses of 50 and 75 mJ/cm2, which gradually increased with subsequent treatments, up to 400 and 150 mJ/cm2, respectively [36, 37]. The studies employed different irradiation schemas. While Köllner et al.  applied laser irradiation three times weekly for 4 weeks in total (12 treatments), Trehan et al.  applied it once weekly for 30 weeks in total (30 treatments) or until complete resolution of OLP lesions, whichever came first. However, Trehan et al.  suggested that his irradiation schema could be improved by increasing laser irradiations to 2–3 times per week in order to achieve quicker responses in treatment of OLP lesions. In total 16 patients were enrolled in both studies. Significant clinical improvement with high patient tolerance, faster healing with immediate analgesia, complete resolution of symptoms, and improvement in extent and severity of recurrence was achieved in 11 patients. The other 5 patients displayed an unchanged clinical response. Even though both studies suggested the effectiveness of 308-nm NB-UVB excimer laser as an additional treatment option for OLP (Table 4), further validation of this technique is still necessary. Since the reports that all types of UV radiation pose a carcinogenic risk presumably also apply to the 308-nm excimer laser, it use should be strongly clinically indicated. Until we know more, excimer laser therapy should be considered experimental and investigational because of insufficient evidence in the literature regarding its efficacy and risk compared to other phototherapy approaches.
Photodynamic therapy (PDT) is basically a technique that uses a photoactive dye (photosensitizer) activated at a specific wavelength of light from a laser or light-emitting diode in the presence of oxygen. The transfer of energy from the activated photosensitizer to available oxygen results in the formation of toxic oxygen species, such as singlet oxygen and free radicals, which can cause cellular damage, membrane lysis, and protein inactivation [38, 39]. PDT has been found to have immunomodulatory effects and may induce apoptosis in the hyperproliferating inflammatory cells that are present in psoriasis and lichen planus . The bactericidal effect of PDT has also been tested on oral biofilms, suggesting that PDT may be useful in the treatment of dental diseases . Clinically used photosensitizers derive from three families: porphyrins, chlorophylls, and dyes .
Regarding OLP treatment, PDT with a porphyrin, methyl 5-aminolevulinate, produced lasting improvement after a single treatment, even after 4 years of follow-up, without visible local or systemic side effects [41, 42]. The phenothiazine dye methylene blue, administered orally or intravenously, is known to have antimicrobial characteristics without any toxic effects and therefore can be preferred as a treatment of choice for lesions in the oral cavity [38, 39]. Methylene blue PDT demonstrated a significant reduction in the signs and symptoms of OLP, with a decrease in the size of OLP lesions and an increase in the symptom-free period [38, 39]. Both authors used the same laser irradiation parameters – laser wavelength (methylene blue has strong absorption at wavelengths longer than 620 nm, with peak absorption at 652 nm) and total dose (120 mJ/cm2). Aghahosseini et al.  reported statistically significant improvement of signs and symptoms 1 week after a single session of laser application and during the follow-up period (up to 12 weeks). Sadaksharam et al.  employed four sessions of laser application and achieved a significant improvement in OLP lesions over a prolonged period (2 weeks). Both authors agreed that no worsening of symptoms or adverse reactions occurred during laser treatment or the follow-up period, and there was no post-treatment discomfort [38, 39].
Photolon®, a novel chlorin e6-derived photosensitizer, is a pigment that has already been successfully applied in the treatment of precancerous lesions , and it produced a similarly beneficial outcome in OLP, reducing the main signs and symptoms in 81% of OLP cases. During PDT, no administration of analgesics or anesthetics is needed; therefore, it is a particularly suitable treatment for the elderly .
To date, the only PDT side effect reported was photosensitivity following systemic administration of the photosensitizer . Apart from this, PDT is considered a safe and effective advanced treatment modality for OLP (Table 5). However, further evaluation of the effectiveness of PDT via well-designed randomized controlled trials with larger numbers of patients and long follow-up (ideally to be checked by a blind evaluator) will be indispensable in the assessment of potential risks and gains. The best approach would be to select groups of patients that are as homogeneous as possible in order to further examine the tissue effects of PDT on T cells.
Table 5. Effects of photodynamic therapy in treatment of oral lichen planus
|Aghahosseini et al. 2006 ||Methylene blue||Diode laser (632 nm)||120 J/cm2||13||1 week; up to 12 weeks' follow-up||Quick and significant beneficial effect on the main symptoms of OLP, with decreased size of lesions and no visible scarring (improvement in 16 lesions, complete remission in 4)|
|Sadaksharam et al. 2012 ||Methylene blue||Xenon arc lamp (630 ± 5 nm)||120 J/cm2||20||1, 4, 7, and 15 days; up to 4 weeks' follow-up||Significant reduction of signs and symptoms of OLP without any side effects|
|Sobaniec et al. 2012 ||Photolon® (chlorin e6–polyvinylpyrrolidone)||Diode laser (660 nm)||90 J/cm2||23||2, 4, 10, and 20 weeks||Beneficial effect on the main symptoms of OLP lesions (reduction in 81% of OLP cases)|
|Kvaal et al. 2013 ||Methyl 5-aminolevulinate||Diode laser (600–660 nm)||75 J/cm2||14||6 months' up to 4 years' follow-up||Significant improvement in OLP lesions 6 months after, and during 4 years' follow up; lasting improvement shown|
To the practicing physician/dentist, the combined problems of unknown etiology, lack of specific therapy, frequency of recurrence, and risk of malignancy have made management of patients with OLP a difficult problem. Patients with OLP usually require a multidisciplinary approach, involving dermatologists, gastroenterologists, and/or gynecologists, apart from dentists. Treatment is mainly focused on increasing oral comfort (in e.g. eating, speaking, sleeping, wearing dental prostheses) and reducing the duration and severity of symptomatic outbreaks, especially during the OLP lesions' periods of quiescence and exacerbation (increased pain and sensitivity), regardless of the clinical type. Currently, topical corticosteroids are widely accepted as the first-line therapy for patients with OLP, even though evidence of their efficacy is not overwhelming [3-5]. Some forms of OLP, most commonly the atrophic and/or erosive forms, are sometimes corticosteroid-resistant . If corticosteroids are ineffective, it is good to know that other treatment options are available. Phototherapy seems to be an interesting new approach that can be successfully applied in treatment of corticosteroid-resistant, painful OLP. However, before initiating phototherapy, dentists should be familiar with all possible phototherapy wavelengths, since the best wavelength should be selected carefully to obtain the best results. Further, dentists need to know the potential advantages and, more importantly, disadvantages of each wavelength, since they are legally obliged to inform patients about short- and long-term side effects and ways to minimize the risk for each phototherapy approach selected. They need to establish clearly the benefit/risk ratio of the selected phototherapy and further compare it to the benefit/risk ratios of the other available treatment modalities in order to make the wisest decision on phototherapy for patients with OLP. However, since there is no solid basis in evidence for the effectiveness of any of these treatments for OLP, it is really difficult to support the effectiveness of any specific phototherapy treatment as being superior.
Although the treatment of OLP with phototherapy showed a lot of promise in the selected articles, the results should be interpreted with caution due to the small number of cases and the difficulty in precise evaluation of the results. Therefore, further research, especially randomized controlled trials with long-term follow up and a larger number of patients, is needed to give any solid recommendation on the use of phototherapy in the field of OLP treatment. It is suggested that further research should be performed with carefully selected and standardized outcome measures using different irradiation conditions in order to better evaluate results and to avoid potential long-term safety risks. Additionally, quality-of-life studies could be helpful in the general evaluation of OLP. Only then will we be able to determine the best phototherapy approach – one that may lead to a uniformly accepted and effective treatment for OLP.