Évaluation de l'effet de la piézo-corticision sur la résorption radiculaire suite au mouvement orthodontique chez le rat
Introduction: Piezo-corticison (PC) is a novel surgical technique that could theoretically increase the rate of orthodontic tooth movement (OTM). However, there is an inherent surgical risk related to this procedure. Strong scientific evidences are still missing for this procedure to be accepted in the orthodontic community, hence the need for further research.  Objectives: This experimental study aimed to evaluate the effect of piezo-corticision (PC) surgery on OTM and on root resorption in a rat model.  Methods: Fourty-eigth male Wistar rats, weighting 250g in average, were divided into 4 groups (n=6 per group) : 1) OTM; 2) OTM + experimental root resorption (ERR); 3) OTM + ERR + PC; 4) OTM + PC. Interventions were done on the right side of the maxilla and the left side served as a control (OTM). The OTM was performed with a NiTi coil ligatured around the upper 1st molar and activated upon stretching when bonded to the upper incisors with a flowable composite resin (force of 50 cN). The ERR was performed by inserting a periodontal probe inside the palatal sulcus of the upper 1st molar and scratching the palatal root for 10 seconds, from the mesial to distal line angle. PC was performed at 1mm from the mesio-palatal crest of the upper first molar (1.5mm depth) using a 0.35mm-thick straight piezoelectric insert. The animals were euthanized 3 and 7 days following the interventions. After sacrifice, rats were dissected and the maxillae were scanned with x-ray microtomography in order to measure the OTM and the amount of apical and cervical root resorption at the furcation. Finally, haematoxylin and eosin (HE) staining was done in order to perform a histological analysis of the samples.  Results: On the 3rd day after the interventions, there was a significantly greater increase of OTM in the OTM + PC (219.68 ± 53.6m) than in the OTM group (154.90 ± 35.6m; p=0.05). Root length was significantly shorter in the group OTM + ERR + PC (2309.27 ±90.3m), than in the group OTM + ERR (2459.74 ± 47m; p<0.01). This result shows an increase in experimental root resorption with the use of PC on the 3rd day. No significant differences were noted on the 7th day for OTM nor root resorption.  Conclusion: PC increased the rate of OTM and the amount of experimental root resorption 3 days after the intervention but these effects were not observed on the 7th postoperative day.
Orthodontic tooth movement Piezo-corticision Root resorption