Partner Magazine logo 15

logo 39 • the CAMLOG Partner Magazine • November 2016 21 CASE STUDY Precision and bonding gap State-of-the-art dental technology is able to fabricate precision-customized abutments with modern milling machines and advanced know-how. However, one should take into account: the procedure or the quality of the result respectively, depend on numerous influencing factors, for example, calibration of the milling machine, milling cutter or sintering process. Predictability and reproducibility are of utmost importance, both for fabrication in the own lab or in centralized fabrication (e.g. DEDICAM). For us, the competent "extended workbench" of an external partner delivers equally perfect results – day by day. The guarantee for maximum safety of a hybrid abutment lies in the fit of the abutment sleeve on the titanium base. Next to bonding itself, the bonding gap plays an elementary role. To achieve a secure bond according to our studies, the bonding gap must be small. In a clinical investigation we compared the bonding gap between the titanium base and the zirconium oxide sleeve of in-house fabricated abutments with DEDICAM structures. Images taken under a scanning electron microscope (SEM) showed the discrepancies which can occur if perfect lab conditions deviate (Figs. 1 to 3) [3]. Fig. 1: Overview of scanning electron microscope (SEM) cross-section for a DEDI- CAM hybrid abutment. Colored white: ZrO2-CAD/CAM abutment on titanium base. Colored red: internal bonding joint with the measuring points L2 - L7 and the external bonding joint (contact with mucosa) with measuring points L1 and L8. Figs. 3a and 3b: DEDICAM-fabricated (left image) and lab-fabricated (right image) zirconium oxide sleeve. Both approaches can achieve high-precision results. Fig. 2: Magnification of the external bonding gap (L1) with a size of 0.21μm. The gap of the bonding joint is therefore more than half as small as for adhesive mount- ing of crowns on teeth, where a bonding joint of 50μm is regarded as being ideal.