Effect of Iontophoresis on the Effectiveness of Nano-Hydroxyapatite and Pro-argin in In-Office Treatment of Dentin Hypersensitivity: A Split-Mouth Randomized Clinical Trial.

Background and objectives Dentin hypersensitivity (DH) treatment is one of the main challenges dentists face in their daily clinical practice. Current therapies provide only temporary relief and require multiple applications to exhibit results, and there is a lack of evidence related to the long-term effects of these agents. Nano-hydroxyapatite (n-HA) and pro-argin (8.0% arginine-calcium carbonate) have recently been used for dentin desensitization with a one-time in-office application, but the effects are interim. However, a standard treatment protocol demands definitive or enduring results. Since iontophoresis amplifies the transport of neutral and ionized drugs across a membrane, the use of these desensitizing agents with iontophoresis may be beneficial to accomplish satisfactory results. This study was conducted to evaluate whether iontophoresis could enable better penetration of nano-hydroxyapatite and pro-argin into the dentin, enhancing and prolonging their therapeutic effect. Materials and methods Forty-five participants with dentin hypersensitivity in the age group of 20 to 60 years were included. In each individual, four teeth with cervical lesions (one from each quadrant) were selected and divided randomly into four groups: group I: desensitizing paste containing nano-hydroxyapatite, group II: desensitizing paste containing nano-hydroxyapatite with iontophoresis, group III: desensitizing paste containing pro-argin, and group IV: desensitizing paste containing pro-argin with iontophoresis; followed by one-time application of the agents. Sensitivity was assessed by tactile, air blast, and cold-graded thermal tests (CGTTs) before and immediately after application, after one week, and at the end of the first, third, and sixth months. Statistical analysis Statistical analysis was done by repeated measures ANOVA for within-group comparison. Intergroup comparison was done using one-way ANOVA and Tukey's post-hoc test. Results All the groups showed a statistically significant reduction in dentin hypersensitivity (p<0.001). The reduction in hypersensitivity in various groups can be graded as group II (3.578/1.800/1.556) > group IV (3.367/1.755/1.555) > group I (2.3781/1.022/0.822) > group III (2.222/0.911/0.778) as evaluated by tactile, air blast, and cold-graded thermal tests, respectively. Group II and group IV presented a significant reduction in sensitivity levels consistent for up to six months. Conclusion Nano-hydroxyapatite and pro-argin can be used effectively for reducing dentin hypersensitivity. Iontophoresis can be a valuable adjunct for their improved delivery, enhancing and prolonging their effectiveness.