Humans ; Mandibular Diseases ; prevention & control ; Osteoradionecrosis ; prevention & control ; Radiotherapy ; adverse effects ; Tooth Extraction

OBJECTIVETo investigate the preventive effect of low-intensity ultrasound on osteoradionecrosis of jaws (ORNJ).

METHODSTwenty-five canines were randomly divided into experimental group (n=20) and control group (n=5). The canines in experimental group received radiation exposure, and then were randomly subdivided into group A (n=10) and group B (n=10). Control group did not undergo radiotherapy. One month after radiotherapy, the fourth mandibular premolars of all animals were extracted. Group B was immediately treated by low-intensity ultrasound for twenty days, group A and control group did not receive any treatment. Two months after tooth extraction, the formation of ORNJ was determined and the occurrence rate of ORNJ was compared between group A and B. The microstructure of the mandible and changes in microvascular density in group A and B were evaluated and compared with those of control group.

RESULTSAll animals in group B and group A developed ORNJ after prophylactic ultrasound was applied for twenty days. Although the imaging examination of bony density of group A and B were lower than normal animals in control group, bone density in group B was significantly better than group A. Micro-CT showed that the trabecular bone volume fraction, trabecular thickness, bone surface/bone volume and trabecular number in group B were respectively (0.187±0.029)%, (0.160±0.039) µm, (12.536±2.558)/mm, (1.227±0.192)/mm, which were all greater than group A [(0.103±0.014)%, (0.069±0.013) µm, (5.598±0.731)/mm, (0.522±0.064)/mm)] (P<0.05).

CONCLUSIONSAlthough the preventive application of low intensity ultrasound can not prevent the formation of ORNJ, but can significantly improve the symptoms of ORNJ.

Animals ; Bone Density ; radiation effects ; Dogs ; Jaw Diseases ; etiology ; prevention & control ; Mandible ; Osteoradionecrosis ; prevention & control ; Radiation Injuries, Experimental ; Random Allocation ; Tooth Extraction ; Ultrasonic Therapy ; methods ; X-Ray Microtomography

OBJECTIVETo investigate the influence of zoledronic acid on vascular endothelial cells.

METHODSThe influence of zoledronic acid on proliferation, migration and adhesion of vascular endothelial cells were tested with 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), cell migration assay and cell adhesion assay. The results of each experimental group were compared with the control group and the data statistically analyzed.

RESULTSIn a concentration of 0-0.5 mmol/L, the absorbance value decreased from 0.09 to 0.34 as the drug concentration increased. Scratch test showed that the change of width of scratch before and after 24 hours in control, low, medium and high concentration groups were (38.7 ± 0.42), (35.8 ± 4.17), (19.9 ± 0.57) mm (P < 0.001), (12.5 ± 3.89) mm (P < 0.05). Adhesion test showed that the absorbance value in control, low, medium and high concentration groups were 1.14 ± 0.18, 0.95 ± 0.13, 0.81 ± 0.11 (P < 0.01), 0.67 ± 0.19 (P < 0.001). Comparisons between control and experimental groups were analyzed by t-test and P values < 0.05 were considered statistically significant.

CONCLUSIONSZoledronic acid inhibits the proliferation, migration and adhesion of vascular endothelial cells.

Cell Adhesion ; drug effects ; physiology ; Cell Movement ; drug effects ; physiology ; Cell Proliferation ; drug effects ; Diphosphonates ; pharmacokinetics ; pharmacology ; Endothelial Cells ; cytology ; drug effects ; Imidazoles ; pharmacokinetics ; pharmacology