Reference Marks on the Occlusion Rims, Record Bases and Master Casts ( mandible )
In the mandible, reference marks should include:
Half way up the retromolar pad – the posterior aspect of the occlusal plane should intersect the midpoint of the pear shaped pad, to ensure the occlusal plane is not set too low (can cause tongue biting) or too high (can cause strain as tongue struggles to place the food bolus back on occlusal table)
Center of the posterior mandibular ridge – Draw this line with a pencil and a straight edge, on the cast, extending out to the land area. The lingual cusp of the maxillary posterior teeth should be centered over this line to ensure denture stability, by reducing fulcruming forces during function
Center of the anterior mandibular ridge – Draw this line with a pencil and a straight edge, on the cast, extending out to the land area. If the anterior teeth are set too far anterior to this line, heavy fulcruming forces can cause tilting and dislodging of the mandibular denture, particularly when the mandibular ridge is severely resorbed.