Resumen

HERNANDEZ S, Filiberto; MARICHI R, Francisco J  y  ALVAREZ, Marco A. Determination of the bone sialoprotein in periodontal ligament with orthodontic forces. Rev. Odont. Mex [online]. 2011, vol.15, n.1, pp.21-26. ISSN 1870-199X.

Bone sialoprotein (BSP) is a component of mineralized tissues such as bone, dentin, cementum and calcified cartilage. BSP is a significant component of the bone extracellular matrix and has been suggested to constitute approximately 8% of all non-collagenous proteins found in bone and cementum. BSP was originally isolated from bovine cortical bone as a 23-kDa glycopeptide but the native BSP has an apparent molecular weight of 60-80 kDa based on SDS-PAGE, which is a considerable deviation from the predicted weight (based on cDNA sequence) of approximately 33 kDa. The protein is highly acidic (pKa of ~ 3.9) and contains a large amount of Glu residues, constituting ~22% of the total aminoacid. This suggests that the protein have several spatially-segmented functional domains including a hydrophobic collagen-binding domain, a hydroxyapatite-nucleating region of contiguous glutamic acid residues and a classical integrin-binding motif (RGD) near the C-terminal. This protein plays a regulatory role in the mineralization and growth of mineral hard tissues. New formation of mineral hard tissue are key role in orthodontic tooth movements characterized by applied mechanical forces that cause tension in the cells which induce a cellular adaptation and this adaptation can activate cellular and molecular responses, that affect the extracellular matrix of periodontal tissues. For this, the aim of this study was to evaluate Bone Sialoprotein expression associated to remodeling of the periodontium after applied orthodontic forces. The upper and lower first bicuspid were applied with braces 0.022 Roth System with 0.016 Nickel Titanium archwires, in all teeth, except the left upper and lower first bicuspid. The first bicuspid without braces (t = 0) and with braces for inducing orthodontic tooth movements during 1, 3, 5, 7 and 9 days; were extracted for analyzing the Bone Sialoprotein expression in the extracellular matrix of the periodontal ligament area. For evaluating the temporal and spatial expression of RNA messengers of Bone Sialoprotein in periodontal ligament the RT-PCR technique was carried out. The expression of Bone Sialoprotein in the experimental group was present at 1, 3 and 9 days and absent at 5 and 7 days of experimental test, suggesting that orthodontic tooth movements will produce significant changes and these changes will be susceptible in the concentrations of the mRNA of Bone Sialoprotein.

Palabras llave : Bone sialoprotein; periodontal ligament; orthodontic forces.