SPP1 and periodontitis: Although no changes were detected in the OPG/RANKL, OCN and OPN proportions for the different experimental groups in the absence of ligature-induced periodontitis, the present study also showed a lower OPG/RANKL proportion, and increase in expression of OCN and TRAP in the hyperglycemic animals, results that were in agreement with those described by Silva et al. [23] and Gennaro et al. [25].