Association of salivary levels of the bone remodelling regulators sRANKL and OPG with periodontal clinical status Tobo ´n-Arroyave S. I., Isaza-Guzma ´n D. M., Restrepo-Cadavid E. M., Zapata- Molina S. M., Martı´nez-Pabo ´n M. C. Association of salivary levels of the bone remodelling regulators sRANKL and OPG with periodontal clinical status. J Clin Periodontol 2012; 39: 1132–1140. doi: 10.1111/jcpe.12012. Abstract Aim: To determine the variations in salivary concentrations of sRANKL, osteo- protegerin (OPG) and its ratio, regarding the periodontal status. Materials and Methods: Ninety-seven chronic periodontitis (CP) subjects and 43 healthy controls were selected. Periodontal status was assessed based on full- mouth clinical periodontal measurements. sRANKL and OPG salivary levels were analysed by ELISA. The association between these analytes and its ratio with CP was analysed individually and adjusted for confounding using a binary logistic regression model. Results: sRANKL and sRANKL/OPG ratio were increased, whereas OPG was decreased in CP compared with healthy controls subjects. Although univariate analysis revealed a positive association of sRANKL salivary levels 6 pg/ml, OPG salivary levels 131 pg/ml and sRANKL/OPG ratio 0.062 with CP, after logistic regression analysis only the latter parameter was strongly and inde- pendently associated with disease status. Confounding and interaction effects of ageing and smoking habit on sRANKL and OPG levels could be noted. Conclusion: Although salivary concentrations of sRANKL, OPG and its ratio may act as indicators of the amount/extent of periodontal breakdown, the mutual confounding and synergistic biological interactive effects related to ageing and smoking habit of the susceptible host may also promote the tissue destruction in CP. Sergio I. Tobo ´ n-Arroyave, Diana M. Isaza-Guzma ´ n, Eliana M. Restrepo- Cadavid, Sandra M. Zapata-Molina and Marı ´a C. Martı ´nez-Pabo ´n POPCAD Research Group, Laboratory of Immunodetection and Bioanalysis, Faculty of Dentistry, University of Antioquia, Medellı ´n, Colombia Key words: Ageing; bone remodelling regulators; chronic periodontitis; diagnostics; osteoprotegerin; periodontal health status; saliva; smoking habit; soluble receptor activator of NF-jB ligand; sRANKL/OPG ratio Accepted for publication 25 August 2012 Chronic periodontitis (CP) is an inflammatory disease that results from a complex polymicrobial infec- tion, leading to tooth-supporting tis- sues destruction as a consequence of the perturbation of the homeostasis between the subgingival microbiota and the host defences in susceptible individuals (Sanz & van Winkelhoff 2011). Notwithstanding, although alveolar bone loss is one of the most important hallmarks of periodontal breakdown (Taubman et al. 2005, Cochran 2008), the mechanisms that underlie bone resorption in CP are not fully understood. In addition to its physiological function, increasing evidence has shown a pivotal role of both the receptor activator of nuclear factor Conflict of interest and source of funding statement The authors declare that they have no conflict of interest. This study has been fully supported by a grant of the Research Development Committee of the University of Antioquia (CODI- Code 8700-677). © 2012 John Wiley & Sons A/S 1132 J Clin Periodontol 2012; 39: 1132–1140 doi: 10.1111/jcpe.12012