Effectiveness of LED in Teeth Whitening
- In all six studies identified for this research, there was at least some improvement in whitening associated with the use of LED light.
- One study found that the use of carbamide peroxide with LED was almost as effective as using hydrogen peroxide, and resulted in less tooth sensitivity for patients.
- Another study found that whether LED light is beneficial may be related to the concentration of hydrogen peroxide that is being used, with lower concentrations benefiting from the use of LED.
Provided below are six scientific studies from 2019 to 2021 that all found some benefit to using LED with teeth whitening gels with either hydrogen peroxide or carbamide peroxide as the active ingredient. For each study we have outlined how it was set up and what the results were.
Of note, all but one of the studies were behind paywalls, but we were able to gather enough information from the abstracts to include them in this research. In most cases the studies are available to rent or purchase, and links have been provided in case additional details that are not available in the public domain are required,
(1) LED/laser photoactivation
- "LED/laser photoactivation enhances the whitening efficacy of low concentration hydrogen peroxide without microstructural enamel changes"
- Published in August 2021
- 20 bovine crowns that were manipulated to be the same size (7x7x2mm) were divided into two groups of 10 each.
- On one group, 6% hydrogen peroxide (HP) was used, while on the other group a combination of 6% HP and a LED/laser was used.
- All specimens were stained "with dark tea solution," and then subjected to three bleaching sessions. Evaluation of both color and "enamel Vickers microhardness" occurred at baseline, 24 hours after each bleaching session, and 7 days after the final bleaching.
- Whitening was effective with both regimens.
- However, better results (increased bleaching) was seen in the specimens that also had LED applied. Unfortunately, the results can't be quantified here because the majority of the study is behind a paywall. The complete study can be purchased for $55.20 or rented for 24 hours for $9.50.
- There was no difference in microhardness between the groups, with neither regimen causing a change.
(2) In-office tooth whitening
- "Clinical evaluation of in-office tooth whitening with violet LED (405 nm): A double-blind randomized controlled clinical trial"
- Published in June 2021
- Four groups were established for the study:
- Group 1: violet LED only
- Group 2: 35% carbamide peroxide (CP) plus violet LED
- Group 3: 35% CP only
- Group 4: 35% HP only
- Although the publicly available summary of the study states that "eight patients were randomized into 4 groups," it appears that it is actually eighty patients, as the reported n-value for each group was 20. With four groups of 20 people each, that would be a total of eighty patients.
- Details on the number of whitening sessions were not publicly available, but it can be concluded there were at least three sessions. If more details are needed, the entire study can be rented for 24 hours or purchased.
- Measurements were taken on whitening, sensitivity, medication needs, and quality of life at baseline, 15 days post-treatment, 180 days post-treatment.
- While group 4, 35% HP only, showed the best results of all groups, the results for group 2, CP plus LED, were comparable, and did show increased effectiveness over groups 1 and 3. Therefore, this study concluded that the use of LED with CP was more effective than the use of CP alone.
- Additionally, while the HP only group got the best whitening results, they were the only group that had patients who required medication for pain within 24 hours of treatment. No patients in the other group had tooth sensitivity that was so severe as to require medication.
- From the conclusion of the study: "...given that pain was not consistently reported in G2, one could suggest that treatment with LED + 35% CP is quite similar to that of 35% HP when used for tooth whitening, but with better pain outcomes."
(3) Effect of violet LED light
- "Effect of violet LED light on in-office bleaching protocols: a randomized controlled clinical trial"
- Published 2020
- This study was available in its entirety.
- Five groups were established for the study:
- Twenty patients were randomized to each of the five groups, for a total of 100 patients. However, each group lost two patients over the course of the study so the final count was 18 patients per group, or 90 total.
- There were different numbers and lengths of sessions depending on which protocol was being used. For example, LED only had a total of 8 sessions, while CP only had a total of three sessions.
- Patients were evaluated for color change, teeth sensitivity, and enamel mineral content.
- The group utilizing HP with LED showed the most color change, followed by HP only and CP plus LED, which had similar results to each other. The results can be seen in the following table, although they are very technical. With a high level understanding that for the first three categories, higher numbers are better, while for the last two categories, small numbers are better, it is clear that HP plus LED performed better than all other protocols.
- Tooth sensitivity was the worst for the two HP groups, followed by CP plus LED. In all of those groups, more than half of the patients reported tooth sensitivity.
- Mineral content was not adversely impacted by the treatments.
(4) A New Approach
- "A New Approach for Dental Bleaching Using Violet Light With or Without the Use of Whitening Gel: Study of Bleaching Effectiveness"
- Published in 2019
- Six groups were established for the study:
- Group 1: placebo only
- Group 2: 35% HP only
- Group 3: 17.5% HP only
- Group 4: placebo with LED
- Group 5: 35% HP with LED
- Group 6: 17.5% HP with LED
- Ninety bovine teeth were randomly assigned to each group, so each group had 15.
- "Three bleaching sessions of 45 minutes were conducted; 21 cycles involving one minute of irradiation by violet LEDs with 30-second intervals were performed during each session of bleaching (GIV, GV, and GVI)."
- Color changes were measured "using a visible ultraviolet light spectrophotometer 7 days after each bleaching session."
- The results showed that the groups treated with 35% HP, regardless of whether LED was used or not, had the most significant improvement. However, the group treated with 17.5% HP plus LED showed more improvement in color than the 17.5% HP only group. Therefore, the results of this study were mixed, showing that LED improved the efficacy of the gel when the potency was 17.5%, but did not have an impact when the potency was 35%.
- Also, of note, the group with LED light only also showed some color improvement, although it was significantly less than for the groups with HP.
- The majority of this study was also behind a paywall, but access for 30 days can be purchased for $25 if more details are needed.
(5) Violet Light-Emitted Diode
- "Clinical Evaluation of In-Office Dental Bleaching Using a Violet Light-Emitted Diode"
- Published in 2020
- Two groups were established for the study:
- Fifty patients were divided evenly between the two groups so each group had a total of 25 patients.
- For both groups, there were two bleaching sessions lasting for 30 minutes that were performed 7 days apart. The only difference between the groups was the use of the LED for group 2.
- Color was evaluated prior to the first session, and 7 days after the second session. Additionally, tooth sensitivity was measured four times throughout the study.
- "Group G2 showed significantly more change than G1." The exact numbers are again behind a paywall.
- There was no difference reported in tooth sensitivity between the groups.
(6) Color stability of dental enamel
- "Color stability of dental enamel bleached with violet LED associated with or without Low concentration peroxide gels"
- Published 2021
- Six groups were established for this study:
- Group 1: no bleaching
- Group 2: Violet LED
- Group 3: 7.5% HP
- Group 4: 7.5% HP plus violet LED
- Group 5: 22% CP
- Group 6: 22% CP plus Violet LED
- Ninety bovine teeth fragments were randomly assigned to the six groups.
- "The color change was analyzed by using a spectrophotometer, at time intervals of 24 h and 6 months after performing the bleaching techniques."
- While all groups showed color improvement, the LED only group showed the least significant improvement, while the CL plus violet LED group showed the best color stability 6 months after treatment ended.
For this research on the effectiveness of LED in teeth whitening, we leveraged the most reputable sources of information that were available in the public domain, including ScienceDirect and the Journal of Applied Oral Science.