Changes in the Relative Position of Teeth in the Construction of Denture Bases

¹ Department of Dental Materials, Faculdade de Odontologia, Universidade de S. Paulo, Sao Paulo, Capital, Brazil

From the statistical analysis of the data obtained, the following conclusions were drawn: The base-plate denture should not be stored, and the denture base should be polymerized as soon as possible. The changes occurring during polymerization were different in upper and lower dentures. Injection and compression molding techniques produced the comparable results. The magnitude of the setting expansion of the investing stone had no significant influence on the changes which occurred in the relative positions of teeth. Perlon mesh inserted in the base of acrylic dentures did not have a significant influence on dimensional change. The polyamid resin tended to produce a contraction in the distance between molars and bicuspids. The changes with the polyamid resin were definitely greater than with the acrylic resin. With the acrylic resin there was a very significant change in the distances between molars and bicuspids, as well as in the anterior to posterior distances. The form of the denture was important in the distortions which occurred. There was a significant change in some areas during the finishing and polishing of dentures.