Tolerance within the sleeve inserts of different surgical guides for guided implant surgery

Objectives Recently, guided implant surgery has been introduced and several studies verified its accuracy. While those studies reported on the accuracy of the entire procedure, this experiment wanted to evaluate the degree of deviation that can occur during the drilling procedure alone, due to the tolerance of the drill in the sleeve insert. Material and methods Drilling was executed in a plexi-glass box with a maximal inclination of the drills within the sleeve insert. Different sleeve inserts, sleeve positions, sleeve heights, sleeve insert heights and diameters were evaluated. Results The two tested sleeve inserts gave a maximum deviation in angulation of 5.2 degrees and a maximum horizontal deviation of 1.3mm at the implant shoulder and 2.4mm at the apex for a 13mm implant. These deviations decreased if the distance of the sleeve above the plexi-glass box became smaller and hand hold sleeve inserts gave less deviation than drill hold sleeve inserts. The deviation increased by longer implant length, larger drill key diameter, shorter sleeves and/or drill key heights. Conclusions For a minimal deviation during the surgery with a stereolithographic guide, it is very important to use the drill in a centric position, parallel to the cylinder. The use of longer drill keys and sleeves are critical for optimal accuracy.