Before re-lining a complete denture, what must be established first?

Before re-lining a complete denture, it is crucial to establish the correct centric relation. Centric relation is defined as the maxillary and mandibular relationship when the condyles are in the anterior-superior positions against the shapes of the thinnest avascular portion of the discs with the complex interarticular fibrocartilage. This position is a bone-to-bone relationship and is the reference point for making a denture that fits properly and functions correctly.

When re-lining a denture, it's important to ensure that the occlusal relationship is stable and accurate in such a way that allows for a comfortable fit and functionality upon the refitting of the new denture lining. Establishing centric relation creates a foundation for accurate occlusion and helps in maintaining the correct anatomy of the maxillofacial structures, which is essential for patient comfort and denture performance.

The other alternatives, such as anterior guidance, maximum intercuspal position, and posterior occlusion, although important considerations in denture construction and adjustment, are secondary to establishing centric relation, which directly influences the overall alignment and fit of the complete denture when relining is performed.