The Effect of Photobiomodulation Therapy on Inflammation Following Dental Prophylaxis: A Randomized Double-Blind Study
Photobiomodulation Therapy (PBMT) is a therapeutic treatment that uses light (typically red or near-infrared light) to induce biological effects in cells and tissues. This therapy is applied using therapeutic lasers or light-emitting diodes (LEDs) and aims to promote a range of benefits, including:
- Reduction of inflammation: The light used in PBMT can reduce inflammatory processes in the tissues.
- Pain relief: PBMT can act as an analgesic, alleviating pain associated with various conditions.
- Acceleration of the healing process: The light stimulates cellular regeneration, which can accelerate the recovery of wounds and injuries.
- Improvement of blood circulation: The therapy can promote vasodilation, enhancing blood flow in the treated area.
- Stimulation of cellular metabolism: PBMT can improve mitochondrial function and increase ATP (adenosine triphosphate) production, providing more energy to cells and facilitating repair processes.
Photobiomodulation therapy (PBMT) has been studied as a non-invasive treatment option for various inflammatory conditions, including periodontal disease (PD) and gingivitis in dogs. This study aimed to evaluate the effectiveness of PBMT in reducing gingivitis following professional dental prophylaxis in dogs, through a prospective, randomized, double-blinded study. A total of 47 dogs participated, with a mean age of 6.5 ± 2.6 years and an average body weight of 28.9 ± 5.3 kg. The left side of the mouth was treated with dental prophylaxis alone (control group), while the right side received dental prophylaxis followed by a single PBMT session using a Class IV therapeutic laser (treatment group). Follow-up observations were conducted on days 1, 3, 8, and 15 post-treatment. The results showed that the PBMT group experienced a significant reduction in gingivitis scores from day 1 to day 15 after treatment. PBMT proved to be an effective adjunctive therapy for reducing gingivitis following dental prophylaxis in dogs.
Introduction
Periodontal disease (PD) is one of the most common health conditions in dogs, characterized by inflammation of the periodontal tissues. Gingivitis, the initial and reversible stage of PD, is primarily induced by bacterial plaque, with professional dental prophylaxis (scaling and polishing) being the most common treatment. However, the use of adjunctive therapies such as photobiomodulation therapy (PBMT) has gained attention due to its beneficial effects in reducing inflammation and accelerating tissue healing. PBMT uses red or near-infrared light to promote therapeutic effects, including analgesia and reduction of inflammation.
This study aimed to evaluate the efficacy of PBMT in reducing gingivitis following professional dental prophylaxis in dogs, as well as to investigate the incidence of PD, gingivitis, and dental calculus in this population of working dogs.
Materials and Methods
The study involved 47 working dogs from the Portuguese National Republican Guard (GNR), aged between 2 and 8 years and weighing between 15 and 35 kg. The protocol was approved by the Ethics Committee of the University of Évora. All dogs were anesthetized for dental prophylaxis and were assessed for PD, gingivitis, and dental calculus. The left side of the oral cavity was treated with dental prophylaxis alone (control group — CG), while the right side received a single session of PBMT using a Class IV therapeutic laser (treatment group — PG).
Follow-up observations were performed on Days 1, 3, 8, and 15 after treatment, and gingivitis and calculus scores were recorded. Data were analyzed using the Mann-Whitney test and multiple regression to predict outcomes based on age, sex, and breed.
Table 1. Periodontal Disease Grades, Gingivitis and Calculus Criteria
| Periodontal Disease Grade | 0 | 1 | 2 | 3 | 4 |
|---|---|---|---|---|---|
| Gingivitis Criteria | Healthy: Pink or pigmented gingiva, no inflammation, no bleeding on probing | Very mild gingivitis: Red, edematous gingiva, no bleeding on probing | Mild gingivitis: Red, edematous gingiva, delayed bleeding on probing | Moderate gingivitis: Red, edematous gingiva, immediate bleeding on probing | Severe gingivitis: Gingival ulceration, immediate bleeding on probing |
| Critérios de Calculus Criteria | None observed | < 25% | 25%-49% | 50%-74% | 75%-100% |
Table 2. Photobiomodulation Therapy (PBMT) Treatment Parameters
| Wavelength (nm) | 980 (for dark-skinned patients), 80% 980 / 20% 808 (for light to medium skin tones) |
| Radiant Power (W) | 3,5 |
| Irradiance (W/cm²) on skin surface | 2,3 |
| Fluence (J/cm²) | 6.2 (mean value for the treated area) |
| Total Energy (Joules) | 217 |
| Treatment Protocol | Continuous movement grid pattern, non-contact, speed 2.5–7.5 cm/second |
| Treatment Area (cm²) | 35 (one side of the mouth) |
| Treatment Time | 1 min 33 s |
Results
The results showed that the group treated with PBMT exhibited a significant reduction in gingivitis scores compared to the control group from day 1 to day 15 post-treatment. The prevalence of periodontal disease (PD) increased with age, being more prevalent in dogs aged between 6 and 8 years. The variables age, breed, and sex showed a significant correlation with the outcomes for PD and gingivitis.
Table 3. Mean Results (± Standard Deviation) of the Assessments Performed in the Control Group (CG) and the PBMT Group (PG)
| Measurement | Group | Day 0 | p | Day 1 | p | Day 3 | p | Day 8 | p | Day 15 | p |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Pontuação de Gengivite | CG | 2,52 ± 0,60 | 0,91 | 2,12 ± 0,76 | 0,00* | 2,11 ± 0,51 | 0,00* | 2,14 ± 0,43 | 0,00* | 2,14 ± 0,43 | 0,00* |
| PG | 2,53 ± 0,54 | 1,20 ± 0,94 | 1,24 ± 0,63 | 1,45 ± 0,56 | 1,48 ± 0,56 | ||||||
| Periodontal Disease (PD) | CG | 1,45 ± 0,50 | 0,68 | ||||||||
| PG | 1,40 ± 0,49 | ||||||||||
| Calculus Score | CG | 1,50 ± 0,64 | 0,93 | ||||||||
| PG | 1,47 ± 0,65 |
In this table, the data for each group (CG = Control Group, PG = PBMT Group) are presented for different evaluation days (Day 0, Day 1, Day 3, Day 8, Day 15). The “p” refers to the statistical value that indicates a significant difference between the groups.
Discussion
Photobiomodulation Therapy (PBMT) demonstrated a significant anti-inflammatory effect, which can be attributed to the improvement of circulation and reduction of inflammation in the periodontal tissues. While dental prophylaxis has an impact on reducing gingivitis, the addition of PBMT provided a substantial improvement, indicating that PBMT can be an effective adjunctive therapy in the treatment of gingivitis in dogs after professional dental cleaning.
Additionally, the results showed that the age, breed, and sex of the dogs influence the severity of periodontal disease (PD) and the incidence of gingivitis. Therefore, the combination of professional dental care with PBMT therapy may be a valuable strategy for managing periodontal health in dogs, especially those with a genetic predisposition or advanced age.
Conclusion
This study concludes that PBMT can be an effective adjunct in reducing gingivitis after professional dental prophylaxis in dogs, demonstrating a positive effect on the animals’ periodontal health. The use of PBMT, combined with good oral hygiene and regular care, can be recommended for the prevention and treatment of gingivitis and other periodontal diseases in dogs.
