Seoul Hee Nam

High-efficiency tooth bleaching using non-thermal atmospheric pressure plasma with low concentration of hydrogen peroxide.

Light-activated tooth bleaching with a high hydrogen peroxide (HP; H2O2) concentration has risks and the actual role of the light source is doubtful. The use of conventional light might result in an increase in the temperature and cause thermal damage to the health of the tooth tissue. Objective: This study investigated the efficacy of tooth bleaching using non-thermal atmospheric pressure plasma (NAPP) with 15% carbamide peroxide (CP; CH6N2O3) including 5.4% HP, as compared with conventional light sources. Material and Methods: Forty human teeth were randomly divided into four groups: Group I (CP+NAPP), Group II (CP+plasma arc lamp; PAC), Group III (CP+diode laser), and Group IV (CP alone). Color changes (ΔE ) of the tooth and tooth surface temperatures were measured. Data were evaluated by one-way analysis of variance (ANOVA) and post-hoc Tukeys tests. Results: Group I showed the highest bleaching efficacy, with a ΔE value of 1.92-, 2.61 and 2.97-fold greater than those of Groups II, III and IV, respectively (P<0.05). The tooth surface temperature was maintained around 37ºC in Group I, but it reached 43ºC in Groups II and III. Conclusions: The NAPP has a greater capability for effective tooth bleaching than conventional light sources with a low concentration of HP without causing thermal damage. Tooth bleaching using NAPP can become a major technique for in-office bleaching in the near future.

Efficacy of Nonthermal Atmospheric Pressure Plasma for Tooth Bleaching

The conventional light source used for tooth bleaching has the potential to cause thermal damage, and the actual role of the light source is doubtful. In this study, we evaluated bleaching efficacy, temperature, and morphological safety after tooth bleaching with nonthermal atmospheric pressure plasma. Tooth bleaching combined with plasma had improved efficacy in providing a higher level of brightness. The temperature of the pulp chamber was maintained around 37°C, indicating that the plasma does not cause any thermal damage. The morphological results of tooth bleaching with plasma did not affect mineral composition under scanning electron microscopy (SEM) observations. On the basis of these results, the application of plasma and low concentration of 15% carbamide peroxide (CP) has a high capability for effective tooth bleaching. It can be documented that plasma is a safe energe source, which has no deleterious effects on the tooth surface.

Effective and long-lasting tooth bleaching by non-thermal atmospheric pressure plasma: A 6-month evaluation

The problem associated with bleached teeth is to return to the original tooth color over time. Because the long-term color stability after tooth bleaching is very important, novel technique is requested. This study is to evaluate the long-term color stability of tooth bleached by nonthermal atmospheric pressure plasma with 15% hydrogen peroxide (HP) or 15% carbamide peroxide (CP). Extracted human teeth were assigned to 4 groups (n = 10): Group 1 was treated with plasma activated 15% HP; Group 2 with 15% HP alone; Group 3 with plasma-activated 15% CP gel; and Group 4 with 15% CP alone. A low-frequency driven helium plasma jet was used. After a 30-min application, teeth were immersed in artificial saliva, and color was assessed using the CIELAB system over 6 months, with the overall color changes (ΔE) calculated relative to baseline. Hydroxyl radical concentration (·OH) was detected using methylene blue (MD) dye. Statistical analyzes were performed with Students t-test, one-way analysis of variance, and post-hoc Duncan tests. Results: Combination treatment of plasma and 15% HP/CP resulted in higher color stability than 15% HP/CP alone throughout the whole observation period (p <; 0.05). The activity of ·OH in combined plasma and low concentration 15% HP/CP was enhanced, relative to bleaching agents alone (p <; 0.05). Long-term color stability of tooth bleaching using plasma with 15% HP/CP was retained for 6 months. Tooth bleaching with plasma is an important factor for ·OH production, which is key to the bleaching effect.