Supervisors info:
Κούρτης Στέφανος, Αναπληρωτής Καθηγητής, Τμήμα Οδοντιατρικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Σαραφιανού Ασπασία, Επίκουρη Καθηγήτρια, Τμήμα Οδοντιατρικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Σιλβέστρος Σπυρίδων, Επίκουρος Καθηγητής, Τμήμα Οδοντιατρικής, Σχολή Επιστημών Υγείας, ΕΚΠΑ
Summary:
INTRODUCTION: Additive manufacturing technologies can be used to fabricate definitive casts for implant supported restorations. The accuracy of the implant analog position in the printed casts is associated with precision of implant supported restoration and with the limitation of biological and technical complications. Data on the accuracy of printed casts for fabrication of full arch implant supported fixed restoration are lacking.
PURPOSE: The purpose of this in vitro study is to evaluate the accuracy of implant analog position of definitive casts, produced by 3D printing technology, estimating the parameters of position and inclination of the implants.
MATERIALS AND METHODS: An edentulous maxillary stone cast with four parallel implants and two inclined implants in distal area right and left, was prepared, and utilized as master cast. The master cast was digitized with lab scanner and ten casts were printed from this STL (standard tessellation language) file with digital light processing method (DLP). These ten printed casts were digitized with the lab scanner and ten STL files were produced. Every STL file was superimposed with the STL file of master cast. Initially, ‘deviations’ between two different casts were estimated with Average Offset and Root Mean Square (RMS). Moreover, ‘deviation’ was estimated in seven positions, corresponding six implants and one point in the center of palate.
RESULTS: When compared with the master cast, the printed casts had a mean ± standard deviation RMS of 0,3417 ± 0,05052 mm (95% CI: 0,3056, 0,3779). The average offset had a mean ± standard deviation of 0,0482 ±0,012 mm (95% CI: 0,04 / 0.06). The maximum ‘deviation’ was calculated in the regions of implants #22 and #24 (#10 and #12 according to ADA, Universal Numbering System) and in the center of palate with mean ‘deviation’ for #22 (0,39mm), for #24 (0,25mm) and in the palate (-0,17mm). The inclined implants were the #16 and #26 (#3 and #14 according to ADA, Universal Numbering System) and the mean ‘deviation’ for implant #16 was: +0,099mm and for the implant #26 was: -0,124mm.
CONCLUSIONS:
-The implant 3D ‘deviations’ of the printed casts from complete-arch digital scans had statistically significant differences compared with those of the master cast but may still be within the acceptable range for clinical application.
-There were statistically significant differences in implant analog ‘deviation’ concerning different positions. The minor ‘deviation’ was observed in positions of implants: #16, #14, #12 and #26 (#3, #5, #7 and #14 according to ADA, Universal Numbering System).
-Inclination did not affect statistically significant the ‘deviation’ comparatively to parallel implants.
Keywords:
3D Printed casts, Accuracy of 3D printed casts, Implant analogs in 3D printed casts, Parameters of position and inclination of the implants, Angulated implants
