Permeability of the Root Canal Wall and Occlusion of Dentinal Tubules by Ag(NH 3 ) 2 F: A Comparison of Combined Use with Pulsed Nd:YAG Laser or Iontophoresis

Abstract

Objective: We used SEM-EDX and the Vickers hardness test to compare the penetration and hardness of silver resulting from use of either (i) pulsed Nd:YAG laser or (ii) iontophoresis, after root canal wall shaping using the standard method of coating with 38% Ag(NH3)2F solution. Summary Background Data: There have not been any reports of penetration and hardness following the application of Ag(NH₃)₂F solution together with laser or iontophoresis. Methods: We used 21 extracted human single-rooted teeth randomly divided into three groups. Group 1 was coated with Ag(NH₃)₂F, Group 2 was irradiated with a Nd:YAG laser after coating with Ag(NH₃)₂F solution, and Group 3 was iontophoresised after coating. Then we observed the permeability of silver through the root canal wall using SEM-EDX. Results: The results show that iontophoresis after coating with Ag(NH₃)₂F solution (Group 3) resulted in the greatest and deepest penetration of silver into the root canal wall. There was no significant difference between teeth in Groups 1 and 2. For the hardness test, the 21 teeth were tested using SEM-EDX test, 7 untreated teeth were used as a control. The results show that Group 2 (laser treatment) teeth were the hardest. Conclusion: We therefore propose that root canals should be treated using irradiation with an Nd:YAG laser that has been coated with Ag(NH₃)₂F solution and that this method provides better results than either iontophoresis after coating, or coating alone.