What change was made to reduce screw loosening in external hex implants?

• A. Increased the external hex from 0.5 mm to 1 mm
• B. Increased the external hex from 0.7 mm to 1 mm
• C. Decreased the external hex from 1 mm to 0.5 mm
• D. Changed the material of the screw

Answer: (B)

The increase of the external hex from 0.7 mm to 1 mm successfully enhances the engagement between the implant and the abutment. This change is significant because a larger hex provides greater surface area contact, which improves the torque retention of the screw. As a result, this change not only helps in stabilizing the structure but also diminishes the risk of screw loosening that can occur over time due to functional forces acting on the restoration.

This design modification is critical in the context of clinical outcomes in implantology, where screw loosening can lead to complications, including implant failure. A stronger connection with an increased hex size essentially means better load distribution and resistance to potential displacement, addressing the primary concerns regarding the integrity of the screw joint.

Other options do not align with established advancements in implant design; they either revert to smaller hex sizes, which would likely worsen stability, or suggest a change in material that does not specifically target the mechanical engagement issues related to screw loosening.