Aim. The aim of this study was to evaluate the precision of an intraoral impression device based on microscopy confocal laser scanning technology. Methods. One plaster abutment of a natural teeth was selected as a test object. In order to achieve an adequate statistical power, 40 scans has to be obtained with a standardized procedure. Scanner was placed in a fixed position and the abutment was fixed on a holder: each scan started from the same position and angulation; the abutment completed four turns at 0°, 30°, 60° and 90°. Every four scans the scanner was cooled down for 5 minutes, shut down and restarted. Scans were imported in an engineering software and superimposed with a best-fit algorithm first and then with a global registration function. They were trimmed with planes intersected on the models, in order to obtain the same surface extension. The same 3-dimensional grid was created and loaded on each 3D scan. The software created control points defined by x, y, z coordinates were the grid intersected 3D-models. Coordinates were exported, converted in their absolute values and summed together for comparison. Results. 44 scans were needed in order to obtain 40 good scans. Four scans were discarded before saving the file because of macroscopical flaws. During model analysis, one scan has to be discarded because one hole, undetected during the scanning process, was found: 39 scans were then analyzed. The 3-dimensional grid intersected the models in 69 locations (L1-L69). The mean range and the mean SD measured for each location were 0,078 mm (min 0,008 mm, max 0,253 mm; SD 0,056mm) and 0,017 mm (min 0,002 mm, max 0,050 mm). Conclusion. To our knowledge this is the first study that evaluated defined locations between scans instead of an overall 3D comparison of the volumes; furthermore it is the first study that has good statistical power. Within the limits of this pilot study, the tested device was considered accurate for a clinical practice.
Precision of a microscopy confocal laser oral scanner: A pilot study
PANTALEO , GIUSEPPE;Gastaldi G;Tecco S;CAPPARE', PAOLO;GHERLONE, FELICE ENRICO
2015-01-01
Abstract
Aim. The aim of this study was to evaluate the precision of an intraoral impression device based on microscopy confocal laser scanning technology. Methods. One plaster abutment of a natural teeth was selected as a test object. In order to achieve an adequate statistical power, 40 scans has to be obtained with a standardized procedure. Scanner was placed in a fixed position and the abutment was fixed on a holder: each scan started from the same position and angulation; the abutment completed four turns at 0°, 30°, 60° and 90°. Every four scans the scanner was cooled down for 5 minutes, shut down and restarted. Scans were imported in an engineering software and superimposed with a best-fit algorithm first and then with a global registration function. They were trimmed with planes intersected on the models, in order to obtain the same surface extension. The same 3-dimensional grid was created and loaded on each 3D scan. The software created control points defined by x, y, z coordinates were the grid intersected 3D-models. Coordinates were exported, converted in their absolute values and summed together for comparison. Results. 44 scans were needed in order to obtain 40 good scans. Four scans were discarded before saving the file because of macroscopical flaws. During model analysis, one scan has to be discarded because one hole, undetected during the scanning process, was found: 39 scans were then analyzed. The 3-dimensional grid intersected the models in 69 locations (L1-L69). The mean range and the mean SD measured for each location were 0,078 mm (min 0,008 mm, max 0,253 mm; SD 0,056mm) and 0,017 mm (min 0,002 mm, max 0,050 mm). Conclusion. To our knowledge this is the first study that evaluated defined locations between scans instead of an overall 3D comparison of the volumes; furthermore it is the first study that has good statistical power. Within the limits of this pilot study, the tested device was considered accurate for a clinical practice.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
