Australian Dental Council (ADC) Practice Test

Retaining pins are most commonly used in inlays for several reasons. Inlays are indirect restorations typically used to restore a decayed tooth that does not require a full crown. When a tooth has significant loss of structure due to decay or fracture, the remaining tooth structure may not be adequate to retain the restoration securely.

Inlays provide the necessary support; however, to ensure a strong bond and stability, retaining pins are placed in the tooth to enhance retention of the inlay material. These pins are specifically designed to provide additional anchorage and help resist the forces of chewing and other stresses that could dislodge the restoration.

Onlays may also require retention methods, but they often cover a larger surface area of the tooth and can engage more healthy tooth structure, thus reducing the need for pins. Full crowns encase the entire tooth and generally do not utilize pins because the crown itself provides sufficient retention. Resin bonding techniques focus more on adhesive properties rather than mechanical retention methods like pins.

The use of retaining pins in inlays serves to fortify the connection between the restoration and the tooth structure, ensuring long-term success and durability of the restoration.