Permanent cements are dental materials used to securely bond restorations, such as crowns and bridges, to natural teeth. They provide a long-lasting solution for dental procedures, ensuring that the restorations remain in place over time. These cements are designed to withstand the forces of chewing and are resistant to moisture and temperature changes. Common types of permanent cements include zinc phosphate, glass ionomer, and resin-based cements. Each type has unique properties, making them suitable for different clinical situations. Dentists choose the appropriate cement based on factors like the type of restoration, the material of the tooth, and the patient's specific needs.