Resumen de Analysis of Daytime Variations in Gingival Crevicular Fluid: A Circadian Periodicity?
Sevim Günday, Ali Orkun Topcu, Esra Ercan, Nermin Yamalik
Background: Volumetric alterations in gingival crevicular fluid (GCF) are widely accepted to be associated with periodontal health/disease. The volume/flow of GCF was shown to be affected by an array of methodological factors. However, relatively limited information is available on whether GCF is subject to circadian rhythm. The main aim of the present study is to assess the possible presence/absence of GCF circadian rhythm. The impact of the sampling technique on daytime volumetric variations is also analyzed.
Methods: The possible daily volumetric variations of GCF with 2-hour intervals (from 08:00 to 18:00 hours) were assessed in 100 tooth sites and 600 GCF samples. Only maxillary incisors were included to eliminate any potential volumetric differences due to tooth dimensions. To analyze the potential impact of sampling technique on GCF volume and daytime variations, at one site modified intracrevicular sampling technique (MIST) was used, whereas the contralateral site was sampled with a deep intracrevicular sampling technique (DIST). Clinical periodontal parameters of the GCF sites were also recorded.
Results: No significant daily variations in GCF volume could be detected. Higher volumetric measures were observed in inflamed subgroups compared with healthy subgroups (P <0.05). MIST was equivalent to DIST with regard to mean GCF volumes and the possible daytime volumetric alterations.
Conclusions: Within the limits of the present study, it can be suggested that daytime variations did not have significant impact on GCF volume. The sampling methodology had no apparent impact on the circadian periodicity of GCF.
Gingival crevicular fluid (GCF) is defined as a specific serum-originating biologic fluid found in periodontal microenvironment and can be harvested from the gingival sulcus of natural teeth.1,2 The flow of GCF is widely accepted as one of the indicators of periodontal health/disease status, as it has the capacity to reflect the cellular response within the periodontium created by both serum and gingival sulcus components.2 Such features are likely to make GCF a reliable tool for better understanding the pathogenesis of periodontal diseases and also for developing susceptible/specific tests for definitive periodontal diagnosis.3 Studies analyzing the volumetric features, enzymatic profile, or cytokine profile of GCF have emphasized the diagnostic potential of GCF as either an early indicator of changes in periodontal health status or a non-invasive prognostic tool.1,4 It has been well demonstrated that GCF volume is affected by an array of factors, including mechanical stimulation, smoking, sex hormones, periodontal therapy, drugs, and circadian periodicity. Volumetric properties of GCF are important because they can affect the findings of concentration-based GCF studies; therefore such factors are a specific concern when considering the improvement of the reliability of GCF-related research.2,5-7 In a number of studies, smoking has been demonstrated to cause a transient but remarkable increase in GCF flow.5,8,9 During the periods of puberty, ovulation, and pregnancy, an increase in the production of sex steroid hormones and a subsequent increase in GCF flow was observed in women.6 Further, GCF production was shown to increase during the healing period after periodontal surgery.10 Since Eisenberg et al.11 detected metronidazole in GCF, Bader and Goldhaber12 showed that tetracyclines are excreted through GCF, and Ho et al.7 recently observed that azithromycin decreases GCF volume, drug usage has been accepted as affecting the results of studies on GCF.
Mechanical stimulation has been demonstrated to increase the flow of GCF.2,13 While harvesting GCF, collecting the fluid without triggering the flow of this biologic fluid is a crucial methodological step because the fluid collected from the sulcus is very limited and GCF flow can be easily affected by mechanical irritation.2,14 Many GCF collection methods (gingival washing, intracrevicular washing, micropipettes, twisted threads placed around and into the sulcus, absorbent paper strips, etc.) are available.2 However, collecting GCF using standardized absorbent paper strips is the preferred methodology using either intracrevicular or extracrevicular sampling methods.13 In extracrevicular sampling methods, the paper strip is placed at or over the entrance of the gingival sulcus to minimize the mechanical irritation that may alter the actual flow of the fluid.13 The intracrevicular method can be further subdivided depending on whether the strip is inserted just at the entrance of the crevice or periodontal pocket (orifice technique),15 inserted to the base of the pocket or until minimum resistance is felt (deep intracrevicular technique),16 or inserted exactly 1 mm into the pocket (modified intracrevicular technique).17 Different techniques of intracrevicular sampling have been widely applied by other investigators.18-22 Circadian periodicity is another factor with the potential to determine the volume/flow of GCF.2 However, little and inconsistent information is available on whether GCF is subject to circadian rhythm.23,24 Bissada et al.23 suggested that GCF actually exhibits a clear circadian periodicity. Similar findings were observed in a study by Bergmann and Deinzer,25 who reported daytime variations of interleukin-1? levels in GCF. In earlier studies, Suppipat et al.24 and Deinzer et al.21 demonstrated that variation in time of day did not influence the flow rate of this biologic fluid. Further, Deinzer et al.21 claimed circadian periodicity was associated with the irritation from GCF sampling.
The first aim of the present study is to assess the possible circadian rhythm of GCF, and the second aim to comparatively analyze the potential impact of modified intracrevicular and deep intracrevicular methodology of GCF sampling on circadian periodicity.
