ACCURACY OF VIRTUALLY PLANNED AND CONVENTIONALLY PLACED IMPLANTS IN EDENTULOUS CADAVER MAXILLAE AND MANDIBLES: A PRELIMINARY REPORT

Statement of problem. The accuracy of mental navigation is thought to depend on the clinician's spatial ability. Mental navigation, therefore, is associated with deviations between the mental plan and the definitive implant position. To learn more about the deviation that might occur, it is important to evaluate the accuracy of mental navigation during placement of implants. Purpose. The purpose of the study was to compare accuracy outcomes between virtually planned and conventionally placed implants, and among surgeons with varying experience. Material and methods. Five completely edentulous sets of maxillae and mandibles from human cadaver heads were scanned by computed tomography. Five surgeons planned and placed 60 implants into these jaws, and accuracy was analyzed for 4 parameters: coronal and apical positions, angulation, and depth. The preoperative and postoperative computed tomographies were aligned in voxel-based registration software, which allowed comparison between virtually planned implant positions and actual implant positions. Data were analyzed with the t test (alpha=.05), ANOVA, and the Scheffe test. Results. Mean (standard deviation) values were as follows: apex, 2.33 +/- 1.20 mm (range, 0.51-6.31 mm); coronal, 1.88 +/- 1.02 mm (range, 0.2-5.0 mm); angle, 7.34 +/- 3.62 degrees (range, 0.19-16.57 degrees); and depth, 0.03 +/- 1.15 mm (range, -3.47 to 2.10 mm). The apex and coronal position and the angle differed significantly between the virtually planned and actually placed implants. Significant between-surgeon differences were found in implant depth and corona] position. The apex and corona] positions differed significantly between the upper and lower jaw, with better performance achieved in the upper jaw. Conclusions. The results found statistically significant differences between the virtually planned and conventionally placed implants and among the 5 surgeons.