Fixed, screwed and removable dentures supported by dental implants.

Implant abutments are classified into either fixed (cemented, screwed, hybrid framework) or removable (over denture)

Abutments for cement retention obtain better passivity, easier to obtain aesthetics, fewer porcelain fractures due to occlusal surface integrity Less fatigue, manipulation in posterior region easier with cement, loosen less often compared to screw retained. Disadvantages: difficult to retrieve unless soft cements are used, gingival retraction made be needed, when permanent cements used, the evaluation and maintenance may be sometimes difficult.

Abutment for attachment used as an attachment drive to retain removable devprosthesis. these include ball abutments, mesostructure bars superstructure attachements (clips,magnets,hader clips,dolder clips)

guidelines for abutment selection: depth of soft tissue measured by measuring vertical height from implant head to gingival margin. iTHIS IS MEASURED USING PERIODONTAL PROBE. implant-abutment interface: EXTERNAL hexagon, external hexagon shaped incorporated into the imlantsystems. However the internal hex came with disadvantages: abutment screw loosening and fracture, mechanical irritation of the tissues and ingree of bacterial toxins, negative impact on stability of peri-implant hard and soft tissues, So the introduction of internal INTRODUCED AND HAS MANY ADVANTAGES. The distribution of intra oral forces deeper within the dental implant.