RESUMEN
Objectives: the purpose of this study was to evaluate whether intra-canal application of controlled direct electric current [DEC] could accelerate the amount of orthodontic tooth movement [OTM] in young adult mixed breed dogs
Methods: fourth premolars of both jaws of five young adult mixed breed dogs were divided into two groups of control and experimental groups. Orthodontic force was applied to both groups using an active NiTi push coil spring. Direct electric stimulation [15µA DC] was conducted by intra-canal usage of electric potential [1.5v]. The experimental teeth were compared with controls in terms of clinical OTM results measured with an electronic caliper every two weeks [four time intervals]. The animals were sacrificed one month [T2] or two months [T4] after initiation; and tissue sections were decalcified for histological evaluation. The data were analyzed using SPSS 16, Shapiro-Wilk test and paired t-test
Results: measurements revealed a statistically significant increase in OTM at electrically stimulated sites compared to the control sites in just one time interval [T3: after four weeks] [P< 0.05]. Histological sections also showed increased osteoblastic and osteoclastic activity at tension and compression sides of the experimental group compared to the control group, respectively at both time intervals [T2 and T4]
Conclusion: direct intra-canal electric current applied by a miniature electric device is effective for increasing the rate and amount of OTM in canine experimental model
RESUMEN
Distraction osteogenesis [DO] is a surgical procedure used to generate large volumes of new bone for limb lengthening. In this animal experimental study, a 30% lengthening of the left tibia [mean distraction distance: 60.8 mm] was performed in ten adult male dogs by callus distraction after osteotomy and application of an Ilizarov fixator. Distraction was started on postoperative day seven with a distraction rate of 0.5 mm twice per day and carried out at a rate of 1.5 mm per day until the end of the study. Autologous bone marrow mesenchymal stem cells [BM-MSCs] and platelet-rich plasma [PRP] as the treatment group [n=5] or PRP alone [control group, n=5] were injected into the distracted callus at the middle and end of the distraction period. At the end of the consolidation period, the dogs were sacrificed after which computerized tomography [CT] and histomorphometric evaluations were performed. Radiographic evaluationsrevealed that the amount and quality of callus formations were significantly higher in the treatment group [P<0.05]. As measured by CT scan, the healing parametersin dogs of the treatment group were significantly greater [P<0.05]. New bone formation in the treatment group was significantly higher [P<0.05]. The present study showed that the transplantation of BM-MSCs positively affects early bony consolidation in DO. The use of MSCs might allow a shortened period of consolidation and therefore permit earlier device removal