Serum Vitamin D Levels and Their Association with Periodontal Parameters in Periodontitis Patients from Northeastern Peninsular Malaysia. - Ibrahim, Hanim Afzan; Zulkipeli, Siti Aisyah; Taib, Haslina; Naim Tuan Ismail, Tuan Nadrah; Nik Mohd Alwi, Nik Aloesnisa; Abdullah, Nurul Huda; Kassim, Nur Karyatee (Bangladesh Journal of Medical Science, 2026)