Authors: Petra Surlin, Anne Marie Rauten, Izabella Silosi, Daniel Pirici, Bogdan Oprea, Laurentiu Mogoanta


Periodontal remodellng produced during dental orthodontic treatment represents a series of biologically-active substances, part of them playing some role in the initiation and propagation of inflammatory processes. The present study aims at evidencing the MMP8, MMP9 and TIMP1 levels intervening in tissular periodontal remodeling produced during orthodontic treatments, accompanied by gingival overgrowth, as a reaction of the marginal periodontium to mechanical stress.
Materials and Method. Selected for the study were 21 patients 13 females and 8 males with ages between 13 and 32 years (17.6-1.3 years) affected with dento-maxillary anomalies, who received orthodontic treatment with fixed apparatus. Sampling from the gingival fluid was performed 6 times, namely: 1 hour prior to the application of the orthodontic apparatus, 4 hours after its application, again after 8 and 24 hours and then 1 and, respectively, 2 weeks later. If gingival hypertrophy was installed (HTG), the hypertrophic gingiva was removed, and an immuno-histo-chemical examination was made. The patient was weekly monitorized in the first 6 weeks during the initial orthodontic treatment, then monthly, samples being taken over from the gingival sulcus on each visit made in the first 6 weeks.
Results. MMP-9 immuno-marking was positive both at corione level and in the deep structures of the covering epithelium. The positive cells at MMP-9 evidenced different intensities at the level of each structure forming the gingival mucous membrane. In four of the cases under analysis, disorganization of the normal layering/stratification of the epithelium was evidenced, along with the presence of numerous red cells in the chorione of the mucous membrane. In such cases, immuno-marking to MMP8 showed a normal intensity, even if few positive cells, dispersed among the extravasated red cells could be observed. Immunologically, MMP8 and MMP9 obey the same pattern, registering maximum values in the first 8 hours after the application of the orthodontic device, after which they begin to decrease, returning to the baseline in the first 2 weeks, for the cases having not developed HTG, while continuing to increase in those evidencing HTG. The TIMP1 levels in GCF are more strongly correlated with those of MMP8 and not with those of MMP9.
Conclusions. MMP8, MMP9 and TIMP1 evolution in various time moments of the orthodontic treatment evidences their involvement in the occurrence of HTG.

  • MMP8
  • MMP9
  • orthodontic treatment
  • periodontal remodeling
  • TIMP1