In vitro testing of the bond between soft materials used for maxillofacialprostheses and cast titanium

Statement of problem. The choice of soft materials for maxillofacial prosth eses is important for covering extraoral defects after tumor surgery or rad iation therapy. The use of cast commercially pure titanium as reinforcement seems to be a suitable option. Purpose. Making use of the advantages of titanium frameworks for maxillofac ial prostheses requires exploring ways of combining it with soft materials. This study investigated such combinations and evaluated discoloration of t he soft material to determine whether it was attributable to the titanium r einforcement. Material and methods. Five soft materials used for maxillofacial prostheses and their bond strengths to cast titanium were tested. Different ways of c onditioning the titanium surface and different adhesives were used. Plain m echanical retention was also studied. The Gretag SPM 100 was used to determ ine the potential effects on coloring after 24 hours of radiation in the Su ntest rapid exposure unit. Results. Suitable material combinations for bonding soft materials to titan ium were found for all soft materials studied. Bond strength varied dependi ng on the chemical basis of the soft material. Results indicated that maxim al bond strengths were obtained by the combinations Supersoft with Super-Bo nd, Supersoft with subsequent silicoating, and bonding with Dentacolor conn ector. Few color shifts attributable to the titanium reinforcement were evi dent in the 2-mm layers of the soft materials applied. Conclusion. The results of this study showed that it is possible to combine a titanium framework and soft silicone materials.