During the extraction of an upper right first molar, the crown disintegrated. Which instrument is used to split the roots for extraction?

When a crown disintegrates during the extraction of a tooth, particularly a molar, it becomes necessary to separate the roots to facilitate their removal. Coupland's chisel is specifically designed for this type of procedure, as it has a wide blade suitable for splitting fragmented roots apart in a controlled manner. This tool allows the dental professional to apply precise pressure and leverage to fracture the roots without causing additional trauma to the surrounding bone or tissues.

In the context of performing extractions, Coupland's chisel is particularly effective for upper molars where the roots may be divergent and close to the sinus cavity. It allows for accurate manipulation around the roots to ensure they can be removed safely and efficiently once separated from the remaining crown or structure. Other tools like the bone rongeurs, Cryer's elevator, and luxator serve different purposes in dental extractions. While they play important roles, they are not specifically tailored for splitting roots once a crown has disintegrated, which is the key concern in this scenario.