Systematic modification and evaluation of a canine model for elevation of the floor of the maxillary sinus

We have modified a canine model for raising the floor of the maxillary sinus by selecting a new surgical approach, and have evaluated the model with computed tomographic (CT) scans and endoscopy. Preoperative CT scans were taken of two beagle cadavers and four healthy, live beagles. The CT data were entered into Simplant software to select a candidate site for a surgical incision located between the first molar and the greater palatine foramen. All animals had the floor of the maxillary sinus raised from the candidate site. During the operation an endoscope was put outside the candidate site and into the maxillary sinus through a lateral puncture to record the condition of the Schneiderian membrane and the position of the candidate site. Postoperative CT scans were used to measure the position of the site, and the positions were compared. Eleven variables were measured on the coronal and sagittal sections. The two most important variables were the mean (SD) horizontal distance from the candidate site to the palatal alveolar ridge (8.1 (0.9)mm) and the residual bone height (2.0 (0.4)mm). There were no significant differences in the anteroposterior or internal-external position of the candidate site. Intraoperative endoscopic views showed the intact, white, and opaque membrane from the candidate site, and the movement of the membrane in the middle of the sinus floor from the lateral puncture. The candidate site is therefore an ideal surgical approach for raising the floor of the maxillary sinus, and the canine model is suitable for research in this area.