Effect of adhesive retention of maxillofacial prostheses. part 2: Time andreapplication effects

Statement of problem. The success of most non-implant-retained extraoral pr ostheses depends on retention derived from skin adhesives. Part 1 of this s tudy found that Skin-Prep Protective Dressing improved the retentive proper ties of adhesives and that Secure(2) Medical Adhesive was stronger than Epi thane-3. Part 2 investigates the application of a second layer of adhesive to the prosthesis, which was earlier noted to improve retention at later ti me periods. Purpose. This study measured the force needed to remove silicone elastomer strips with Secure(2) Medical Adhesive from the skin of human subjects. Tes ting was performed before anti after the removal of the strips and reapplic ation of the adhesive. Material and methods. Secure(2) Medical Adhesive was painted on silicone ru bber strips and placed in a nonsequential random order of the 3 variables t o 3 sites on the ventral forearms of 21 human subjects and tested over an 8 -hour period. The bond strength was measured at 0, 4, and 8 hours. After a reapplication of adhesive over the existing adhesive, additional bond stren gth measurements were made at 4 and 8 hours. Testing was at 10 cm/min in an Instron. ALL subjects had Skin-Prep coating applied before adhesive applic ation. Results. Bond strengths for both single applications and reapplications of the adhesive were greater at 0 hours and became significantly weaker after the 4- and 8-hour periods. The second application of the adhesive produced the strongest bonds when measured at 4 hours (110 N/m). Bonding was signifi cantly higher at 8 hours if a second application of adhesive was applied at 0 or 4 hours. Conclusion. The results of this study indicate that the bond strength of si licone elastomer to skin decreased over an 8-hour interval. After removal o f the silicone rubber strip and reapplication of Secure2 Medical Adhesive o ver the existing adhesive, bond strengths increased.