###### Abstract  
Background: The crevicular fluid analysis represents a useful diagnosis tool, with the help of which noninvasive cellular metabolic activity can be analyzed. The aim of the study is to investigate comparatively IL1\(\beta\) and IL6 in the gingival crevicular fluid of clinically healthy adolescents and young adults during the acute phase of orthodontic treatment. Methods: Gingival crevicular fluid was collected from 20 patients (aged between 11 and 28) undergoing orthodontic treatment. Measurements were taken before (T0) and after 24 h after distalization forces were activated (T1). IL1\(\beta\) and IL6 were analyzed using Elisa tests. The statistical tests used were two-sided t tests. Results: Between the two time periods there was a significant raise both in the crevicular fluid rate (0.57 \(\mu\)L at T0 vs. 0.95 \(\mu\)L at T1, \(p\) = 0.001) and in IL1\(\beta\) levels (15.67 pg/\(\mu\)L at T0 vs. 27.94 pg/\(\mu\)L at T1, \(p\) = 0.009). We were able to identify IL6 only in a third of the sites. There is a significantly increased level of IL\(\beta\) at T1 in adolescents, more than in young adults (42.96 pg/\(\mu\)L vs. 17.93 pg/\(\mu\)L, \(p\) = 0.006). Conclusions: In the early stage of orthodontic treatment, the periodontal tissues of adolescents are more responsive to orthodontic forces than those of young adults. Keywords:cytokines; dentistry; ELISA test; gingival crevicular fluid; orthodontic treatment; orthodontics +
Footnote †: journal: _Sci._  
Footnote †: journal: _Sci. mechanical role in removing foreign particles from the gingival crevicular fluid. This role was confirmed by administrating pathogenic bacterial complexes in germ free gingival sulci. After the initial epithelial necrosis, clinical signs of inflammation were detected, with the induction of an inflammatory exudate. However, after 48 h, the gingival sulcus returned to the normal aspect [1]. In addition to the volumetric raises caused by the presence of inflammation, increases in the flow rate of gingival fluid were observed in other pathological or physiological conditions, such as: the circadian rhythm (in the morning, between 6-10 a.m an increase in flow rate was observed), physiological factors (sexual hormones, mastication), smoking, periodontal surgery (a certain increase in the volume appeared in the post-surgery phase) [2]. In case of a minor inflammation, the gingival fluid rate is 0.05-0.2 uL/min. Its daily flow rate is between 0.5-2.4 mL [3]. The gingival fluid is composed of substances derived from serum, host inflammatory cells, periodontal cells and oral bacteria. The molecular components include electrolytes, proteins, cytokines, antibodies, antigens, bacterial or local enzymes [4]. A detailed analysis of these components provides us with useful information regarding the cellular metabolic activity during either the periodontal therapy or the orthodontic treatment. Certain components of the gingival fluid being quantified, they can act as biomarkers in identifying periodontal diseases, monitoring and evaluating the response to the periodontal treatment [5,6]. Evaluating the biomarkers during the orthodontic therapy allows us to monitor the effectiveness of the treatment, to anticipate the future outcome and also to individualize the treatment according to the response of tissue to different force intensities [3,4]. This is significant especially in adult patients, where the pace of the periodontal restructuring occurs in a longer time than in juvenile patients [7]. Through physiological dental migrations, the periodontal tissues are continuously subjected to remodeling action. While the physiologic migrations are achieved through a slow process, the orthodontic migrations can occur through both accelerated and slow mechanisms. These movements are influenced by the intensity of the applied forces, or by the biological response of the periodontal ligament. Inflammatory reactions that appear in response to mechanical stimuli determine periodontal inflammation, thus determining bone remodeling.