Does orthodontic treatment induces dental pulp cellular death? Caspase-3 and-9, HSP60 and Tunel expression

Objective. To evaluate the hypothesis of human dental pulp cell death during Orthodontic Treatement (O.T.) and the degree of apoptosis through the expression level of the proteins Caspase-3,-9, TUNEL and HSP60. Materials and methods. Human dental Pulp were coming from both male and female patients (N=20; age 10-14years). The technique used was the Straight Wire, which involves Nickel-Titanium or Steel archwires. The increase of pressure applied on teeth was gradual. Some patients were subjected to a premolar extraction after 3 months treatment, and others after 6 months. Samples were Bouin-fixed, paraffin-embedded and afterwards processed for immunohistochemistry using anti-caspase-3,-9 antibody, anti-HSP60 and TUNEL. Results. Increasing of Caspase-3,-9 expression occurred in 3 and 6 months O.T. samples, while in control pulps positivity was detected mainly at odontoblasts level. HSP60 was not expressed in control samples and very weak in 3 months O.T. samples, it was expressed instead in 6 months O.T. samples, the expression of TUNEL is evident in all samples but increased at 3 and 6 months specimen. Conclusion. Our hypothesis is supported by the increasing expression of Caspase-3,-9, HSP60 and TUNEL after 3 and 6 months of orthodontic traction revealing a time-dependent relationship