What was the main issue identified with external hex implants?

• A. Screw loosening
• B. Inadequate stability
• C. Material fatigue
• D. Excessive bone loss

Answer: (A)

The main issue identified with external hex implants relates to the phenomenon of screw loosening. This is primarily due to the design of the external hex connection, which can lead to micro-movements at the interface between the implant and the abutment. Over time, these micro-movements can cause the screws securing the abutment to the implant to become loose, resulting in compromised healing and stability of the restoration placed on the implant.

In contrast, while inadequate stability, material fatigue, and excessive bone loss are important considerations in implant dentistry, they do not specifically highlight the distinctive problem associated with external hex implants. Inadequate stability might occur in various types of implants, material fatigue refers to issues that arise from the long-term use of materials, and excessive bone loss can result from various factors, including improper placement or loading. However, screw loosening due to the external hex design is a distinctly recognized issue, making it the most relevant concern in this context.