There are complex undercut areas in the cavities of maxillary defects as well as a weak and sensitive tissue. Therefore, if the impression material is pushed deep into the undercuts in order to take impressions of the maxillary defect, the material may remain in the cavity of the defect, or the tissue may be damaged. In the case of partial dentures with maxillary defects, it is necessary to take precise impressions of the abutment teeth, where safety is essential in the undercut areas in the cavities of maxillary defects.
In the present study, the aim was to take impressions for maxillofacial prostheses safely and accurately. We developed a novel impression method using a polyaddition silicone rubber impression material mixed with Vaseline. An examination of its physical properties showed, that this mixture of Vaseline with silicone impression material had the same degree of permanent strain and dimensional stability as polyaddition silicone rubber impression material alone. Also, the elastic deformation was of the same order as that of irreversible hydrocolloid impression material. Clinical application revealed, that the new impression material in the mouth was extremely easy to remove, the patients felt little pain, and the complex shapes in the cavities of maxillary defects were reproduced with good accuracy.
