– Cement-retained restorations: utilize pre-fabricated or laboratory made abutments to create units that are similar to prepared teeth. Each abutment is screwed onto the implant, and a restoration is cemented to it.
– Screw-retained restorations: are either screwed directly to an implant, or are screwed to a pre-fabricated abutment. In this type of restoration, an access hole remains in the occlusal surface of the restoration.
– Overdentures: can gain support and retention using ball attachments, which are connected onto the implants, or by using a bar which is connected to a few implants.
Main indications, benefits and concerns to take into account for each option:
|Main indications:||Single or multiple restorations.|
|Benefits:||A fixed solution.
Resembles standard crown and bridge procedures.
Better esthetics (no occlusal access holes).
|Concerns:||Cement removal may be difficult.
Difficult to retrieve.
|Main indications:||Multiple-unit restorations.|
|Benefits:||A fixed solution.
Easy to retrieve.
|Things to keep in mind:||Occlusal stability may be compromised
due to screw access holes.
Full Arch Restorations
|Main indications:||Totally edentulous jaw.|
|Benefits:||Increased quality of life due to better retention and stability of the denture.
Simple and easy cleaning and maintenance.
|Things to keep in mind:||At least two implants are required.
Implants should be placed parallel.
Impression types: There are two impression types in implant dentistry:
Transfers the accurate location and 3D position of each implant to the laboratory.
Transfers the accurate location and 3D position of each abutment to the laboratory.
Each one of these impression types can be captured using one of three impression techniques:
Closed tray impression technique – is similar in many ways to conventional crown and bridge impression techniques. An impression coping is attached to each implant, and an impression tray filled with impression material records the oral structures. After setting, the impression tray is taken out of the mouth, each impression coping is attached to an analog, and then re-installed into its own position in the impression.
Open tray impression technique – in this technique, holes are made in the impression tray above each impression coping (hence the name “open tray”). As the impression tray filled with impression material is placed, the tips of the impression copings or their long screws must extend out of the tray and be visible to the dentist.
Digital impressions – this technique utilizes specially made scan bodies, that should be recognizable by the specific digital system, to capture the correct three-dimensional position of each implant and the surrounding oral structures.
Basic impression type comparison table:
|Impression component||Long Impression component with retentions|
|The outcome||Impression components remain embedded within the impression material when tray is taken out of the mouth|
|Impression component||Short impression component, with no retentions|
|The outcome||Impression components remain attached to the implants when tray is taken out of the mouth, and later are re-installed into the impression material|