ABSTRACT
BACKGROUND: Oral aphthosis is a painful ulceration of mucus membranes characterized by round or oval lesions with central necrosis and erythematous haloes. Due to unknown etiology, treatment is highly controversial and based mainly on individual experience. The aim of this study was to investigate the safety and efficacy of topical penicillin 6.3.3 for the treatment of recurrent aphthous stomatitis. MATERIALS AND METHODS: This randomized, double-blind, controlled clinical trial was done in Shahid Sadoughi Hospital Clinic in Yazd (2011-2012). Fifty patients aged 15-45 with recurrent oral aphthosis were randomly divided into two groups. After obtaining informed consents, patients in the case and control groups were treated (four times/day for a week), respectively, by topical penicillin 6.3.3 powder and placebo in similar vial. The patients who had acute-onset oral aphthae (≤48 h of appearance) with diameter ≥5 mm were included. History of sensitivity to ß-lactam antibiotics and cephalosporin; spontaneous recovery during <5 days in previous episodes; concurrent systemic, infectious, or any autoimmune disorders; history of taking drugs (local or systemic) from 2 weeks prior to presentation; alcohol or drug abuse; smoking cigarette or tobacco; and poor compliance were exclusion criteria. Patients were examined in days 0, 3, 6, and 8. The main outcome measure was reduction in the median pain. Burning, pain, erythema, and inflammation were recorded as complications. RESULTS: Of 25 patients receiving penicillin, 13 were female and 12 were male. Regarding the pain score (mean difference = 1.6 vs. 0.88, P = 0.012) and size of aphthus (mean difference = 9.43 vs. 1.24, P = 0.008), patients who received penicillin had significantly better results than the placebo group on day 8 after the treatment. The mean duration to healing was 3 days for penicillin group and 6 days for placebo group (P = 0.016). No topical or systemic adverse effects were observed. CONCLUSION: Our study showed a dramatic response to topical penicillin with respect to placebo. Hence, it seems that penicillin could be a safe and effective option in managing oral aphthosis.
ABSTRACT
Hydrogen adsorption on graphene in commensurate periodic arrangements leads to bandgap opening at the Dirac point and the emergence of dispersionless midgap bands. We study these bandgap effects and their dependence on periodicity for a single hydrogen adsorbate on periodic graphene supercells using spin-polarized density-functional theory calculations. Our results show that for certain periodicities, marked by a scale factor of three, the bandgap is suppressed to a great extent, and has a special level structure around the neutrality point. We present explanations for the origin of the changes to the band structure in terms of the ab initio Hamiltonian matrix. This method may be used to obtain a more accurate tight-binding description of single hydrogen adsorption on graphene.
