Covering the Implant Prosthesis Screw Access Hole: A Biological Approach to Material Selection and Technique

The implant abutment junction leaks with repeated use, which pumps oral flora and nutrients into the internal aspects of the implant and the abutment. Traditionally, cotton has been used to cover the abutment screw and has provided an environment where anaerobic bacteria propagate and are ultimately pumped into the fragile peri-implant tissues.

Figure 2. Clinical sample of cotton screw cover placed under gutta-percha after 4 years in function. Patient reported foul odor and taste under function. Figure 3. Commercial-grade polytetrafluoroethylene (PTFE) tape is precut and autoclaved prior to use. Figure 4. Two percent chlorhexidine is used to clean the internal aspects of the channel prior to placing the screw cover. Figure 5. The channel is wiped with isopropyl alcohol and dried. Figure 6. The PTFE tape is rolled into a cigar shape, delivered into the screw access channel and condensed. Figure 7. Sufficient PTFE tape is used to fill the screw access to 2 mm from the occlusal surface. Ideally, this will serve to block the graying effect of the metal channel. Figure 8. Light cured composite resin is applied following hydrofluoric acid etching and silanation of the ceramic ring. Figure 9. The completed composite cover is finished and polished.

Figure 10. The ceramic plug is pressed concurrently with the crown. It has an opaque apical layer added to prevent show through from the screw access channel as well as an antirotation portion to enable improved seating. Figure 11. The plug is shown seated in the crown. It will be adhesively bonded, after application of ceramic etch and silane; then composite resin is used. Figure 12. A clear polyvinyl siloxane (PVS) material is syringed with a narrow diameter tip into the abutment, directly onto the head of the screw. Figure 13. Excess clear PVS will be wiped away and the plug allowed to polymerize. Figure 14. Should retrieval become necessary, the PVS plug is simple to remove with an explorer.