2.1.

Study Design

The present single-center, randomized, controlled, single-blind study received approval from the Human Research Ethics Committee (HCPA protocol 11-0365). All participants signed a statement of informed consent prior to any clinical procedure.

2.2.

Participants, Interventions, Randomization, and Blinding

Forty-two consecutive adult patients with OLP were enrolled in the study between February 2012 and November 2012. The sample size was calculated according to previously published articles.^12–14 Inclusion criteria were age 21 years or older, symptomatic atrophic/erosive OLP, and histopathological diagnosis of OLP based on the criteria proposed by the World Health Organization. The exclusion criteria were pregnant or nursing women, histological signs of dysplasia, OLP therapy in the previous three months, amalgam restoration near the lesions, and the use of medications associated with oral lichenoid reaction. Tabagism was not considered exclusion criteria for this study.

The patients were randomly assigned to one of the two treatment groups using computer-generated random number tables. Only one researcher knew in which group the patients were allocated. This unblinded researcher was not involved in any evaluation during and after the treatments. The patient was not blinded to the treatment.

The clobetasol group consisted of 21 subjects who received topical clobetasol propionate gel (0.05%), and the LPT group consisted of 21 subjects submitted to laser therapy. Figure 1 displays the study flowchart. The participants received verbal and written instructions on how to apply all the medications used.

Fig. 1

Flowchart showing subject enrollment and follow-up.

2.3.

Topical Clobetasol Propionate 0.05%

The medication was prepared with a hydroxyethyl cellulose gel and prepackaged (15 g) in a labeled tube by a pharmacist. Only two nonconsecutive missing applications were accepted.

To evaluate possible systemic absorption, blood cortisol levels were monitored at 8:00 am in the second (Day 14) and fourth (Day 30) week of treatment considering a normal range from 5.0 to $25\mu \text{g}/\mathrm{dl}$.³⁸

2.4.

Laser Phototherapy

LPT was administered by a single professional using a continuous wave diode laser (InGaAlP; MM Optics, São Carlos, São Paulo, Brazil) with a wavelength of 660 nm (visible red). Irradiation was performed in punctual contact mode with a spot size of $0.04{\mathrm{cm}}^2$, power output of 40 mW, output density of $1000\mathrm{mW}/{\mathrm{cm}}^2$, energy density of $6\mathrm{J}/{\mathrm{cm}}^2$, 6-s exposure time per point, and 0.24 J of total energy per point. The number of points varied based on lesion size; therefore, it was not possible to calculate the total dose for all the cases. LPT was administered three times a week (Monday, Wednesday, and Friday) for four consecutive weeks, totaling 12 sessions. The output power of the equipment was checked using a power meter (Laser Check; MMOptics LTDA, São Paulo, Brazil).

2.5.

Candidiasis Prevention

All patients received prophylactic anti-mycotic medication (Nystatin oral suspension $100,000\mathrm{USP}/\mathrm{ml}$, Micostatin®; Bristol-Myers Squibb Brasil S.A, São Paulo, Brazil) administered three times daily.^8,39 The medication was delivered in individual 5-ml dispensers. The patient used an anti-mycotic during all the days of treatment with clobetasol and LPT. During follow-up, the medication was discontinued.

2.6.

Clinical Evaluation

All patients were evaluated at baseline (Day 0), once a week during treatment (Days 7, 14, 21, and 30) as well as at four weeks (Day 60) and eight weeks (Day 90) after the discontinuation of treatment (follow-up period) (Fig. 2). Evaluations were performed by a single professional who was blinded to the allocation of the participants to the different treatment groups. Evaluations involved the recording of symptoms, clinical signs, functional scores, Beck anxiety inventory (BAI), and photography. At each evaluation, the patients in both groups were asked to report any unusual effects that might have been related to the therapy protocol.

Fig. 2

Diagram of experimental protocol employed.

2.7.

Statistical Analysis

Statistical analysis was carried out using the SPSS version 18.0 (SPSS Inc., Chicago, Illinois). Data were analyzed using a generalized estimating equations (GEE) test, which combined tests for treatment differences and changes in treatment response over time. The GEE followed by Bonferroni’s posthoc test was used to determine the significance of differences between therapies over time considering the VAS score, CS, functional scores, and CR score. The chi-squared test was used to analyze the RR. All statistical tests were performed with a significance level of 5% ($p<0.05$). The statistical tests used took into account the correlated nature of the repeated measures of each patient. Analyses were performed on an intention-to-treat basis.

3.1.

Clinical Scores

The CS results are graphically represented in Fig. 3. At baseline (Day 0), the patients exhibited lesions with atrophic and erosive areas associated or not to hyperkeratotic lesions, with a similar mean CS in both groups. The CS remained similar in both groups, decreasing progressively through to Day 21. However, from Day 30 to the end of the follow-up period (Day 90), the LPT group had significantly lower scores in comparison to the clobetasol group ($p<0.001$). At Day 90, the LPT group exhibited more hyperkeratotic lesions and fewer atrophic/erosive lesions than the clobetasol group ($p<0.001$). Moreover, the clobetasol group demonstrated a worsening of clinical aspects, with the recurrence of atrophic and erosive lesions. Figure 4 illustrates the CS findings in a patient from the LPT group.

Fig. 3

Mean clinical scores (standard error of mean) in clobetasol and laser phototherapy (LPT) groups during experimental period; Clobetasol group presented significant (*) worsening of clinical aspects, with more atrophic and erosive lesions than LPT group at Days 30, 60, and 90 (A and B).

Fig. 4

Effect of LPT on lateral border of tongue in 82-year-old male; (a) erosive/ulcerative lesion at Day 0; (b) erosive lesion at Day 7; (c) effect of LPT at Day 30; (d) clinical aspect of tongue at Day 90.

3.2.

Symptom Score

All patients had symptoms at baseline (Day 0). The overall mean VAS score was 6.6 ($\pm 2.0$), with no statistically significant difference between groups. The mean VAS scores decreased significantly in both groups by Day 14 ($p<0.001$) (Fig. 5). The change in mean VAS scores did not differ significantly between groups during treatment. In the follow-up period, the LPT group maintained a stable mean VAS, whereas a significant increase was found in the clobetasol group, leading to significant differences groups ($p<0.05$).

Fig. 5

Mean symptom (visual analogue scale) scores (standard error of mean) in clobetasol and LPT groups during experimental period; Both groups demonstrated reductions in pain throughout treatment. Clobetasol group exhibited significant (*) increase in pain on Days 60 and 90.

3.3.

Functional Scores

On Day 0, both groups exhibited moderate difficulty in chewing and fluid intake as well as an altered sense of taste. Both groups demonstrated significant improvements in the four aspects analyzed throughout treatment ($p<0.001$). At Day 30, improvements were found in both groups in all functional scores. In the follow-up period, a significant difference between groups was found only with regard to altered sense of taste, for which the clobetasol group had a worse behavior (Fig. 6).

Fig. 6

Mean functional scores (standard error of mean) in clobetasol and LPT groups during experimental period; Both groups demonstrated significant improvements in chewing (a), fluid intake (b), swallowing (c) and altered sense of taste (d) throughout treatment, with significant (*) difference between groups in fluid intake at Day 7 (B). Significant (*) worsening in sense of taste in clobetasol group during follow-up period (Days 60 and 90).

3.4.

Clinical Resolution and Recurrence Rates

Partial or complete CR was achieved in both groups. Complete resolution at Day 30 occurred in 28.6% (6 patients) of the clobetasol group and 61.9% (13 patients) of the LPT group.

Table 2 displays the RR in both groups. At Day 60, only one case of recurrence (4.8%) was found in the LPT group, whereas 10 cases (47.6%) were found in the clobetasol group ($p<0.001$). At Day 90, the LPT group had a higher percentage of patients with no signs of recurrence, but the difference between groups did not achieve statistical significance ($p=0.276$).

Table 2

Recurrence rate in clobetasol and LPT groups at follow up (Days 60 and 90); significant worsening in CS in clobetasol group at Day 60.

3.5.

Beck Anxiety Inventory

The overall mean BAI score at baseline (Day 0) was $34.02\pm 9.46$ (32.9 in the clobetasol group and 35.1 in the LPT group), demonstrating severe anxiety. Similar significant decreases were found in both groups throughout treatment ($p<0.001$). At Day 90, the clobetasol group demonstrated an increase in anxiety, whereas the LPT group maintained a constant mean score, with a significant difference between groups ($p<0.05$) (Fig. 7).

Fig. 7

Mean Beck anxiety inventory (BAI) scores (standard error of mean) in clobetasol and LPT groups during experimental period.

3.6.

Side Effects

Three patients (14.3%) of the clobetasol group reported a transient local burning sensation immediately after the first two days of drug application and two (9.5%) reported gastrointestinal distress, which was resolved with the concomitant intake of omeprazole. The mean cortisol level in the clobetasol group was $8.85\pm 3.59$ on Day 14 and $10.67\pm 3.96$ on Day 30, which were within the normal endogenous cortisol pattern (5.0 to $25\mu \text{g}/\mathrm{dl}$).³⁸ No side effects were reported in the LPT group.