When should casts be mounted in centric relation (CR) during denture fabrication?

When should casts be mounted in centric relation (CR) during denture fabrication?

• A. When MI is impossible to maintain or doesn't exist (complete dentures, partial dentures, multiple teeth being restored or replaced)
• B. After recording jaw relations in maximum intercuspation
• C. Only for fixed partial dentures
• D. After occlusal equilibration

Answer: (A)

Centric relation provides a stable, repeatable jaw position that can be used as a reference when natural tooth contacts can't define the bite. When maximum intercuspation cannot be achieved or maintained—such as in complete dentures or when many teeth are missing or to be replaced—the occlusal setup would be unreliable if based on MI. Mounting the casts in centric relation gives a reproducible starting point to arrange teeth and determine occlusal vertical dimension, independent of tooth contacts. This is why mounting in CR is indicated in those scenarios. The other situations aren’t appropriate triggers for CR mounting in denture fabrication, since MI-based mounting would be used if MI could be reliably recorded, and occlusal equilibration follows after the denture is already in use.

Centric relation provides a stable, repeatable jaw position that can be used as a reference when natural tooth contacts can't define the bite. When maximum intercuspation cannot be achieved or maintained—such as in complete dentures or when many teeth are missing or to be replaced—the occlusal setup would be unreliable if based on MI. Mounting the casts in centric relation gives a reproducible starting point to arrange teeth and determine occlusal vertical dimension, independent of tooth contacts. This is why mounting in CR is indicated in those scenarios. The other situations aren’t appropriate triggers for CR mounting in denture fabrication, since MI-based mounting would be used if MI could be reliably recorded, and occlusal equilibration follows after the denture is already in use.