Comparison of Different Impression Techniques When Using the All-on-Four Implant Treatment Protocol

Area of Science:

• Dental Implantology
• Prosthodontics
• Biomaterials

Background:

• Accurate impressions are critical for successful All-on-Four implant restorations.
• Choosing the appropriate impression technique is essential for minimizing errors in implant positioning.

Purpose of the Study:

• To compare the accuracy of open-tray and closed-tray impression techniques in an in vitro model for All-on-Four therapy.
• To evaluate impression accuracy at both abutment and implant levels.

Main Methods:

• Fabrication of an edentulous maxilla analog with four implants.
• 40 impressions using open-tray and closed-tray techniques at abutment and implant levels.
• Analysis of linear and rotational displacement using a coordinate measuring machine.

Main Results:

• The open-tray technique showed significantly less linear and rotational displacement than the closed-tray technique.
• Abutment-level impressions with the open-tray technique were more accurate than implant-level impressions.
• The closed-tray technique demonstrated less rotational dislocation at the implant level compared to the open-tray technique.

Conclusions:

• Impression technique significantly impacts the accuracy of All-on-Four implant restorations.
• The open-tray method is generally more accurate, particularly for abutment-level impressions.
• Specific scenarios, like implant-level impressions, may favor the closed-tray technique for rotational accuracy.