A traffic light system for the surface topography of CAD/CAM abutments

Authors: Carsten Fischer, Peter Gehrke

Should or how should a CAD/CAM abutment be processed in the submucosal area? The answer to the question is a key factor for the long-term soft tissue integration of an implant restoration.

Abutments form the transmucosal bridge between the implant body and the superstructure. The implant structure has various functions. The primary aim is to create an anchor for the crown. The abutment also prevents the penetration of bacteria that could hinder long-term implant success. In order to effectively fulfill this barrier function, the surface quality in the submucosal area of ​​the abutment is crucial.

What relevance does this have for the dental technician?


Particularly when producing individual CAD/CAM abutments, the dental technician should pay attention, among other things, to the surface topography in the submucosal area. The aim must always be that the peri-implant mucosa adapts firmly to the abutment surface. With regard to the abutment material, zirconium oxide is increasingly being used alongside titanium and gold. Advantages of this high-performance ceramic include the light color and, in particular, the low bacterial accumulation on zirconium oxide. There are various factors to consider when it comes to processing (link to other articles).

Highly polished or with a defined roughness?


Particularly when producing individual CAD/CAM abutments, the dental technician should pay attention, among other things, to the surface topography in the submucosal area. The aim must always be that the peri-implant mucosa adapts firmly to the abutment surface. With regard to the abutment material, zirconium oxide is increasingly being used alongside titanium and gold. Advantages of this high-performance ceramic include the light color and, in particular, the low bacterial accumulation on zirconium oxide. There are various factors to consider when it comes to processing (link to other articles).

The surface topography in the submucosal area should be specifically developed. It is assumed that there is a threshold value at which the accumulation of bacteria and plaque on the surface is low and at the same time the attachment of fibroblasts is supported. The ideal surface is a medium roughness value (in μm: Ra = 0,21 – 0,40).

Caution: A surface that is too rough poses the risk of increased plaque accumulation. However, if the surface is too smooth, the fibroblasts in the peri-implant mucosa cannot “grow” optimally.

Traffic light system: A classification of roughness could be as follows

rough > 0,42 μm (red: increased risk of plaque accumulation)

medium rough = 0,21 – 0,5 μm (green: optimal)


smooth < 0,2 μm (yellow: reduced adhesion of fibroblasts)

Traffic light system for classifying roughness in the basal area

How can the nano-roughness defined as ideal be achieved?


CAD/CAM abutments require post-processing to achieve the average roughness value. This is the only way to achieve optimal conditions for the desired attachment of the peri-implant tissue. In order to generate a perfect surface finish, a documented work protocol is recommended. For example, the basal area of ​​the abutment can be processed with special diamond rubber polishers and an appropriately coordinated protocol, thus generating a surface with a residual roughness of 2 to 4 µm.

Post-processing the surface of a CAD/CAM hybrid abutment in the basal area with special rubber polishers (e.g. Panther smooth / sirius ceramics). The desired residual roughness of 0,2 – 0,4 μm is achieved (see SEM image).

Further information: You can read more about CAD/CAM hybrid abutments - especially for bonding - here: Link Article.

Note: Abutments are medical devices that are classified as semi-critical (RKI). Professional cleaning is therefore recommended. Evaporation is not sufficient and fails to achieve the disinfection effect required by standards. In its summary of an expert discussion, EADT eV presents the study situation on the various cleaning options in detail. Download the expert paper: here

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