Aim or purpose: The present study aimed to compare prostaglan- din E2 (PGE2) and interleukin-1ß (IL-1ß) levels, which are the indicators of bone resorption and found in the gingival crevicular fluid (GCF), between smokers and nonsmokers who were under fixed orthodontic treatment.

Materials and methods: A total of 30 subjects (15 smokers and 15 nonsmokers), who had different types of dental malocclusion and applied to the Yu€zu€ncu€ Yıl University Faculty of Dentistry, Depart- ment of Orthodontics for treatment, were enrolled in the study. After placing orthodontic brackets, leveling stage was completed using 0.12, 0.14 and 0.16 Ni-ti arch wires. In the stage where 16 9 22 steel arch wires have been used, GCF samples were col- lected from the distal aspects of maxillar incisors using periopaper. IL-1b and PGE2 levels in GCF were analyzed by ELISA method. Results: It was determined that gingival index and bleeding on probing parameters were lower but pocket depth was higher in smokers as compared to nonsmokers. The difference between the groups was statistically not significant. Total and concentration levels of IL-1ß and PGE2 were higher in smokers versus nonsmok- ers. However, the difference between the groups was not found statistically significant.

Conclusions: The results of the study revealed no statistically sig- nificant difference between smokers and nonsmokers in terms of GCF cytokine levels during orthodontic treatment. Further studies that investigate GCF cytokine levels during orthodontic treatment performed with different forces in larger series are required.