**Core Concept**
Titanium casting involves a process where titanium alloy is molded into the desired shape. This process is crucial in dental and orthopedic implants due to titanium's biocompatibility and high strength-to-weight ratio.

**Why the Correct Answer is Right**
Titanium casting is typically done using the **investment casting** technique, also known as lost-wax casting. In this process, a wax pattern of the desired shape is created and then coated with a refractory material. The wax is melted out, leaving a cavity that is filled with molten titanium. The titanium is then solidified, and the refractory material is removed to reveal the final casting. This process allows for the creation of complex shapes and precise control over the titanium's microstructure.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to titanium casting.
**Option B:** This option is not a correct casting method for titanium.
**Option C:** This option is incorrect because it does not accurately describe the titanium casting process.

**Clinical Pearl / High-Yield Fact**
Titanium casting is a critical process in creating dental and orthopedic implants, as it allows for the creation of precise, custom shapes that can withstand the stresses of the human body.

**Correct Answer: D. Investment casting**