Final answer:
Suturing is the recommended attachment method for long, dense, or more extensive hair restorations. Melted wax application, cementing, and embedding are not recommended.
Step-by-step explanation:
The attachment method that affords the strongest bond and is recommended for long, dense, or more extensive hair restorations is Suturing. Suturing involves using surgical stitches or sutures to secure the hairpiece to the scalp. This method provides a secure and durable attachment, especially for larger and heavier hair restorations.
On the other hand, melted wax application, cementing, and embedding are not commonly used for hair restorations as they may not provide the same level of strength and longevity.