This study evaluates the effectiveness of topical NAVS naphthalan in the treatment of oral lichen planus (OLP) and recurrent aphthous stomatitis (RAS). Half of participants with OLP and RAS will receive topical NAVS naphthalan in adhesive paste, while the other half will receive 0.05%-betamethasone dipropionate in adhesive paste. Our hypothesis is that NAVS could be efficient in the treatment of OLP and RAS, with effects comparable to that of topical steroids.

Non-Aromatic-Very rich in Steranes (NAVS) naphthalan is a transparent, earth mineral oil prepared by a complex set of procedures of separations and refining, starting with a special oil that is used as the raw material for brown naphthalane, which has been successfully used in the treatment of psoriasis. In order to remove potentially mutagenic polycyclic aromatic hydrocarbons (PAHs), liquid chromatography was used. UV / VIS (ultra violet / visible light) spectrophotometry confirmed that PAHs were bellow detection threshold. Additionally, the precise distillation process has concentrated steranes, which are important bioactive constituents. Since steranes contain similar chemical structure as well-known bioactive substances, such as vitamin D3 and steroid hormones, the assumption is that NAVS is effective in the treatment of oral diseases which have immune genesis such as OLP and RAS.

Today, topical steroid preparations are considered as first-line therapy for many chronic immune-mediated inflammatory diseases of the oral mucosa. Risks of short-term use of topical corticosteroids are clinically insignificant, while their long-term use is not recommended because of potential side effects, such as mucosal atrophy, secondary infection with Candida albicans, possible systemic absorption and suppression of the adrenal gland.

Study participants are adult patients of the Department of Oral Medicine, School of Dental Medicine in Zagreb, with a clinically and histologically proven OLP or RAS in the acute stage of the disease.The treatment outcome of the OLP patients will be measured by clinical improvement and subjective symptomatic relief. The outcome of RAS patients treated by NAVS naphthalan or by betamethasone will be measured clinically by the decrease in number and size of lesions as well as by subjective symptomatic relief over treatment period. One member of the team, who will not evaluate the therapeutic effect, will took care of the allocation of test and control preparations. At the end of the study, a randomization code will be opened and statistically analysed. In both clinical and subjective domains, of both clinical conditions, the improvement rate will be measured by comparing these readings, as the percentual reduction of clinical scores and symptoms. Since the data will not be normally distributed, methods of nonparametric statistics will be used: Wilcoxon test for dependent and Mann-Withney test for independent samples. Baseline intergroup differences will be assessed by Mann-Withney test. For the interpretation of the average values, medians and interquartile ranges (IQR) will be used. Fisher exact test will be used to compare gender representation among the groups. Statistical analysis will be performed using MedCalc Software 13.0.0.0 (Acacialaan 22, 8400 Ostend, Belgium). P value lower then 0.05 (p< 0.05) will be considered statistically significant.

Inclusion Criteria:

• for OLP patients: adult patients with a clinically and histologically proven OLP (Al-Hashimi et al, 2007)
• for RAS patients: in the acute stage of the disease, according to Lehner (1968), at least 2 episodes per year

Exclusion Criteria:

• for OLP patients: younger than 18 years, hepatobiliary system diseases, lichenoid reaction (amalgam, drugs) or lichen planus with lesions in contact to restorative materials (Zakrzewska et al, 2005), the current comparative systemic or local anti-inflammatory treatment (antibiotics, corticosteroids, non-steroidal antirheumatic drugs, chemotherapeutics) (Lo Muzio et al, 2001; Nolan et al, 2006; Rodriguez et al, 2007) and pregnancy.
• for RAS patients: patients younger than 18 years, haematological deficits (assessed by complete blood count (CBC), iron (Fe), vitamin B12, hypersensitivity to toothpaste and oral mouth rinse solutions (assessed by medical history) (Nolan et al, 2006), pregnancy, inflammatory bowel disease (assessed by medical history), significant immunodeficiencies, current comparative systemic or topical anti-inflammatory treatment (antibiotics, corticosteroids, nonsteroidal antirheumatics, chemotherapeutics) (Lo Muzio et al, 2001; Nolan et al, 2006; Rodriguez et al, 2007).

Yes, de-identified data are available upon request.