Relationship of investing medium to occlusal changes and vertical opening during denture construction.

Four groups of 20 dentures with nonanatomic teeth were processed using four different investing techniques. The incisal guide pin was measured and recorded before processing and again after processing and remounting of each denture on the articulator. The difference between the two readings indicated vertical changes during processing. The least vertical opening and a complete absence of occlusal changes occurred in the dentures invested in the plaster of paris core with an artificial stone cap. The following conclusions were made: (1) Vertical opening in denture processing can be minimized by investing in plaster of paris molds with a stone occlusal matrix. (2) Tooth movement is minimized by the use of this investment combination. (3) Inadequate investing procedures contribute to vertical opening and occlusal discrepancies. (4) Vertical opening of dentures processed by compression molding technique may be due to other factors. This can only be determined by further investigation.