In-vitro evaluation of the tolerance of surgical instruments in templates for computer-assisted guided implantology produced by 3-D printing.
OBJECTIVE
The aim of this in-vitro study was to compare the tolerance of surgical instruments in surgical guides produced by 3-D printing, without metal sleeves to a surgical guide with conventional metal sleeves from two different manufacturers.


METHODS
Lateral movements of drill tips caused by tolerance between the sleeve and drill key and between the drill key and the drill were recorded after application of a standardized force to the surgical instruments. Four groups were tested: Control 1 (C1): metal sleeve from commercially available surgical system 1; Test 1 (T1): 3-D-printed sleeve for surgical system 1; Control 2 (C2): metal sleeve from commercially available surgical system 2. Test 2 (T2): 3-D-printed sleeve for surgical system 2.


RESULTS
The mean total lateral movement was 0.75 mm (0.5-1.04 mm) in the C1 group and 0.91 mm (0.54-1.34 mm) in the C2 group. The mean amount of movement from tolerance between sleeve and drill-guiding key was 0.31 mm (range 0.22-0.41 mm) in C1 and 0.42 mm (range 0.29-0.56 mm) in C2. This lateral movement was in mean reduced by 0.24 mm (32%) in T1 and by 0.39 mm (43%) in T2 group. This reduction was statistically significant in both groups (P < 0.001).


CONCLUSIONS
The tolerance of surgical instruments and the lateral movements of the drills were significantly reduced by the use of 3-D printing with reduced sleeve diameter. This reduction could improve the overall accuracy in computer-assisted template-guided implant dentistry. The lateral movement of the drill can be further reduced by using a shorter drill and a higher drill key. This can be considered during implant planning and CAD/CAM of surgical guides.
Clinic for Fixed and Removable Prosthodontics and Dental Material Science, University of Zurich, Zürich, Switzerland.
David
D
Schneider
Florian
F
Schober
Philipp
P
Grohmann
Christoph H F
CH
Hammerle
Ronald E
RE
Jung
D003758:Dental Implantation, Endosseous / Q000295:instrumentation*; D004867:Equipment Design; D066298:In Vitro Techniques; D066330:Printing, Three-Dimensional; D025321:Surgery, Computer-Assisted; D013525:Surgical Instruments
3-D printing; dental implants; guided surgery