CAMLOG and Science

CAMLOG&Science – Chapter 3 ZrO 2 ABUTMENTS – WEAR AND RECOMMENDATIONS FOR USE Wear is an important aspect regarding the long-term success of implant- abutment connections. Stimmelmayr et al. (2012a) evaluated the wear of the interface between CAMLOG ® titanium implants and one-piece zirconia abutments and compared it to titanium abutments in an in vitro study. Che- wing simulation was performed with a similar test set-up as designed by Steinebrunner et al. (2005; Fig. 10A). After loading with 1.200.000 cycles at 100N, neither implant or abutment fractures nor abutment screw loose- ning or screw fractures occurred. However, SEMmicrographs revealed more wear and damage at the implants when they were connected to ZrO 2 abut- ments. The authors supposed that the reason for these differences was the stress distribution between components of different rigidity: When using ZrO 2 abutments on titanium implants, deformation energy is distributed to the material with the lower elastic properties, i.e., titanium, which results in increased wear and abrasion. Use and processing of ZrO 2 abutments were also discussed at a consensus conference and the following recommendations were developed (Beuer et al., 2011): • ZrO 2 qualities differ in their mechanical and optical properties. Only tho- roughly tested, well known and scientifically documented ZrO 2 qualities should be used. • One-piece monoblock ZrO 2 abutments with inner connections should not be used in the lateral tooth area. In the front area, one-piece abutments with outer connections and appropriate dimensions show fewer problems. • Two-piece, bonded ZrO 2 abutments, do not show any limitations in use as long as they have appropriate dimensions. • On standardized ready-for-use ZrO 2 abutments, crowns should be fixed in a conventional way since surplus fixation material is difficult to remove if the crown margin is placed subgingivally. • When using individually CAD/CAM-prepared ZrO 2 abutments with which themargin can be placed to bewell accessible, also adhesive / semi-adhesive systems may be used. • In restorations which are fixed only by adhesion and without additional retentive preparations, classical adhesive multiple step systems should be used. • It is strongly recommended not to fix ZrO 2 restorations provisionally.