In a cavity preparation in which the remaining thickness of dentin is more than 1.5mm, the ideal base is:
**Core Concept**
The ideal base in a cavity preparation is determined by the remaining dentin thickness to ensure the longevity and success of the restoration. A thicker dentin layer provides sufficient support for the base, allowing for a more conservative restoration.
**Why the Correct Answer is Right**
When the remaining dentin thickness is more than 1.5mm, a **self-cured or chemically cured resin base** is the ideal choice. This type of base provides a strong, durable, and biocompatible seal, allowing for a more conservative removal of tooth structure. The resin base also helps to prevent the leakage of bacteria and other substances into the pulp, reducing the risk of pulpitis and other complications.
**Why Each Wrong Option is Incorrect**
**Option A:** A **copper band base** is not suitable for a cavity preparation with a remaining dentin thickness of more than 1.5mm, as it may be too thick and may not provide a good seal.
**Option B:** A **zinc oxide-eugenol (ZOE) base** is not ideal for a cavity preparation with a remaining dentin thickness of more than 1.5mm, as it may not provide sufficient support for the base and may be more prone to leakage.
**Option C:** A **silver amalgam base** is not suitable for a cavity preparation with a remaining dentin thickness of more than 1.5mm, as it may be too thick and may not provide a good seal, and also has the disadvantage of being non-removable.
**Clinical Pearl / High-Yield Fact**
When choosing a base in a cavity preparation, always consider the remaining dentin thickness to ensure a more conservative and successful restoration.
**Correct Answer:** D. Self-cured or chemically cured resin base