Systematic Modification And Application For A Dog Model Of Maxillary Sinus Floor Elevation With Endoscope

PURPOSE: the purpose of this study was to(1) modify and evaluate a dog model for maxillary sinus floor elevation(MSFE),(2) explore the availability of MSFE with the help of endoscope in this model,(3) assess the stability of implant placement in combination with MSFE,(4) apply this model for confirming the differences between non-grafted and grafted Bio-Oss in sinus.MATERIALS AND METHODS: A candidate site(CS) in six beagles was selected as a surgical approach for MSFE, which was located between the first molar and the greater palatine foramen. During MSFE, an endoscope was put outside the CS and into the maxillary sinus through a lateral puncture opening to observe the schneiderian membrane's condition and the CS's position. Postoperative CT scans for all animals were used to measure the CS's position. Twelve sinus floor elevation surgeries in six beagles were performed bilaterally and randomly repaired with the following 2 groups: the test group consisted of endoscopic MSFE(n=6); the control group consisted of osteotome MSFE(n=6). All surgeries were evaluated from the two safe indexes(including perforation of the sinus membrane and nasal bleeding) and the two effective indexes(including the intraoperative elevated height and bone grafts volume). Twelve-sinus floor elevation in the other six beagles were performed bilaterally and randomly repaired with the following 2 groups: group A consisted of endoscopic MSFE and implant placement(n=6); group B consisted of endoscopic MSFE, Bio-Oss graft, and implant placement(n=6). The implant stability and new bone formation were evaluated by the following viewpoints: initial stability(IS), implant stability quotient(ISQ), CT examination, sequential fluorescent labeling, Micro-CT examination, and histological analysis(Van Gieson staining). The results were analyzed by several statistical methods.RESULTS: In modification and evaluation of the model part, intraoperatively endoscopic views and CT scans noted the CS was located in the middle of the sinus floor. In application of the endoscope part, no perforations of the sinus membrane and no nasal bleedings occurred in both groups. The intraoperative elevated height and the bone volume in the test group were higher than in the control group. In evaluation of the implant stability part, IS, ISQ, CT, Micro-CT and histological analysis showed that there was good bone connection between double-layer cortical bone and implant in both groups. In evaluation of non-grafted and grafted bone in sinus part, all examinations showed that there were serious new bone formation in the lower parts of implants in both groups and middle and upper parts of implants in group B.CONCLUSSION:(1) The candidate site is an ideal surgical approach for raising the floor of the maxillary sinus, and the canine model is suitable for research in this area.(2) Endoscopic lifting of the floor of the maxillary sinus is a safe and effective approach based on direct observation in beagles.(3) There is a good implant stability for implant placement simultaneously in this model.(4) There is more new bone formation in MSFE with grafted bone than non-grafted bone.