Iontophoresis is the utilization of low amperage direct current to deliver therapeutic medication to underlying tissues. It is an electrical mean to deliver medications into the joints and surrounding area without an injection. Iontophoresis is based on the basic principle of electrical physics that likes repel likes. Certain medications in their salt form in solution bear a charge or stated another way, are ionized. By applying a direct current of like polarity the ions of the medication are driven into the underlying tissues. This occurs because the ions are repelled from the electrode of similar polarity and attracted toward the opposite electrode.

There are various medications that have usage in the treatment of TMD, as well as in general dental usage, which are ionized in their dissociated salt form. As a result they may be therapeutically applied with iontophoresis.