J Periodontol • August 2001 Effect of Non-Surgical Periodontal Therapy on C-Telopeptide Pyridinoline Cross-Links (ICTP) and Interleukin-1 Levels Khalaf F. Al-Shammari,* William V. Giannobile,* † Wayne A. Aldredge, ‡ Vincent J. Iacono, ‡ Robert M. Eber,* Hom-Lay Wang,* and Richard J. Oringer ‡ 1045 Background: Biochemical markers harvested from gingival crevic- ular fluid (GCF) may be useful to identify and predict periodontal disease progression and to monitor the response to treatment. C- telopeptide pyridinoline cross-links (ICTP), a host-derived breakdown product specific for bone, and interleukin-1β (IL-1), a potent bone- resorptive cytokine, have been associated with periodontal tissue destruction. The aim of this study was to examine the effect of non- surgical periodontal therapy on GCF levels of ICTP and IL-1. Methods: Twenty-five chronic periodontitis subjects were moni- tored at 8 sites per subject at baseline prior to scaling and root plan- ing and 1, 3, and 6 months after therapy. Four shallow (probing depths <4 mm) and 4 deep (probing depths ≥5 mm) sites were mon- itored for both marker levels and clinical parameters. GCF was col- lected for 30 seconds on paper strips, and levels of ICTP and IL-1 were determined using radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) techniques, respectively. Clinical mea- surements included probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP). Results: Deep sites exhibited significantly (P <0.001) higher ICTP and IL-1 levels compared to shallow sites at all time intervals. ICTP demonstrated a stronger association to clinical parameters than IL- 1 including a modest correlation (r = 0.40, P <0.001) between ICTP and attachment loss. Significant improvements in PD, CAL, and BOP were observed at 1, 3, and 6 months in all sites (P <0.01). However, non-surgical mechanical therapy did not significantly reduce ICTP and IL-1 levels over the 6-month period. Further examination of sub- jects based on smoking status revealed that ICTP levels were signif- icantly reduced at 3 and 6 months and IL-1 levels reduced at 3 months among non-smokers only. Conclusions: A single episode of non-surgical mechanical ther- apy did not significantly reduce biochemical markers associated with bone resorption in patients exhibiting chronic periodontitis. Future longitudinal studies are warranted to specifically evaluate the rela- tionship between C-telopeptide pyridinoline cross-links and peri- odontal disease progression. J Periodontol 2001;72:1045-1051. KEY WORDS Gingival crevicular fluid/analysis; periodontitis/therapy; pyridinoline cross-links; interleukin-1/adverse effects; bone resorption; disease progression. * Department of Periodontics/Prevention/Geriatrics, School of Dentistry, University of Michigan, Ann Arbor, MI. † Center for the Biorestoration of Oral Health, School of Dentistry, University of Michigan. ‡ Department of Periodontics, School of Dental Medicine, University at Stony Brook, Stony Brook, NY. T raditional methods used in the diagnosis of periodontal dis- ease include assessments of gingival inflammation (e.g., bleed- ing on probing) and periodontal tis- sue destruction (e.g., probing depth [PD], clinical attachment level [CAL]). Advantages associated with these methods include being easy to use, cost-effective, and relatively non- invasive. 1 However, the major dis- advantage of these techniques is that they are static diagnostic para- meters, indicating disease history and not current disease status. 2 Therefore, these methods cannot identify highly susceptible patients or actively deteriorating sites. In addition, limitations in measure- ment reliability necessitate a change of 2 to 3 mm before a site can be identified as having experi- enced a significant anatomic event. 3,4 Thus, there is a need for the development of new diagnostic tests that can detect the presence of active disease, predict future dis- ease progression, and evaluate the response to periodontal therapy, therefore improving the clinical man- agement of periodontal patients. 5 A potential new diagnostic in- volves the direct measurement in the gingival crevicular fluid (GCF) of a bone-specific molecule called pyridinoline cross-linked carboxy- terminal telopeptide of Type I colla- gen (ICTP). The value of pyridino-