The aims of our study were 1) to evaluate levels of gingival crevicular fluid( GCF) human cathelicidin peptide LL-37 and serum vitamin D3 in smoker and non-smoker patients with chronic periodontitis(CP) 2) to determine whether any correlation between GCF LL-37 and vitamin D3 serum levels exist and 3) to asses the correlation between clinical parameters and biochemical markers

Background: Cathelicidin LL-37, an antimicrobial peptide, is part of the host innate immune response in the oral cavity. The aims of this study are to evaluate; gingival crevicular fluid (GCF) levels of LL-37, serum vitamin D3 levels and periodontal clinical recordings in smoker and nonsmoker patients with chronic periodontitis (CP). Methods: This study consisted a total of 60 volunteers including 20 smoker patients with CP (CP-1 group), 20 non-smoker patients with CP (CP-2 group) and 20 periodontally healthy subjects (CTRL group). Prior to participation, the design and purpose of the research were explained to each subjects, and written informed consent form was obtained from 60 individuals before the study. The periodontal status of the patients were determined by measuring the probing depth (PD), clinical attachment level (CAL), gingival index (GI), plaque index (PI) All clinical parameters were measured on six sites per tooth from the full-mouth teeth (mesiobuccal, distobuccal,midbuccal, mesiolingual, distolingual and midlingual) using a William's periodontal probe calibrated in millimeters by the same examiner. All samples were obtained on the day following clinical examinations of the individuals. The deepest six pockets site per individual were chosen for collection of GCF across both of the periodontitis groups. Six pocket locations showing a lack of clinical inflammation were also tested to guarantee collection of a sufficient volume of GCF across the CTRL groups. GCF levels of LL-37 were measured by ELISA and serum levels of vitamin D3 were analysed by High-performance liquid chromatography (HPLC). Statistical analysis were performed.