Vitamin D deficiency and risk of recurrent aphthous stomatitis: updated meta-analysis with trial sequential analysis oleh Sadeq Ali Al-Maweri, Gamilah Al-Qadhi, Esam Halboub, Esam Halboub, Nader Alaizari, Asma Almeslet, Kamran Ali, Safa A. Azim Osman