Tabela 2 – Salivary Sampling.
The parameters used in photobiomodulation are important to achieve the expected result. In the present report, the patient showed improvement in symptoms with vascular photobiomodulation at the red wavelength (660nm), although infrared in direct local application under the salivary glands is usually indicated in cases of xerostomia. This result is in agreement with studies that demonstrated the systemic action of vascular photobiomodulation (Lizarelli, 2023; Mikhaylov, 2015).
Further to the wavelength, other parameters are important such as the power, which was 100mW, the energy per point which was 180J and the equipment beam area (0.04 cm²). It’s important to note that all parameters must be informed so that clinicians and readers know exactly what treatment was performed and that, if they so wish, they can reproduce the same protocol with their patient. The number of irradiations must also be questioned. There are no reports in the literature in which the effect of the benefit of photobiomodulation is sustained for more than 7-10 days, however the ideal minimum interval time still needs to be defined (Abueva, 2022; Sousa 2019; Brzak, 2018).
Many authors report in their studies a reduction in xerostomia and an improvement in salivary flow, pH, IgA content and saliva buffering capacity. Some studies claim that PBM is able to regenerate salivary gland tissue (Plavnik, 2003A review suggests the effectiveness of PBM in the treatment of xerostomia (Sousa, 2019). A study in humans observed the effects of PBM on salivary glands of patients with xerostomia, where the authors used different parameters, infrared laser λ = 830 nm and red laser λ = 685 nm, and found an improvement in flow in both, being even better in patients treated with λ = 830 nm, this effect was observed in the long term, suggesting a regenerative effect on the salivary glands (Brzak, 2018). However, there is not enough evidence to support the claim of a cumulative or regenerative effect of PBM in a general sense, as studies were carried out on few patients or without control groups (Golez, 2022).
Close communication between the dentist (who has to deal with adverse effects) and the prescribing physician is necessary to obtain the best outcome for the patient (Wolff, 2017). Although xerostomia was a commonly reported outcome, objectively measured salivary flow rate was rarely reported. Furthermore, xerostomia was assessed primarily as an adverse effect rather than the primary outcome of medication use. (Wolff, 2017).
In this clinical case presented, the patient’s psychiatric treatment is not expected to end, so the protocol is now applied in a preventive manner and not just to cure the symptoms. Studies have observed a cumulative effect of salivary gland repair when locally irradiated. With the prevention of xerostomia, the patient achieved a clear increase in her quality of life, reported by herself with the following words:
“Dry mouth can’t be resolved even with water, but the laser has improved it a lot. I stayed really well for a week, I was fine for several days, so much so that I couldn’t wait to do it again, because I was feeling good and wanted to stay well”.
At each session, the patient reported a reduction in symptoms, which encouraged her to attend, as she noticed that she no longer needed to wake up to drink water. With the prevention of xerostomia, the patient achieved a clear increase in her quality of life, demonstrating that vascular photobiomodulation can be an interesting low-cost non-invasive treatment.
The effect of laser exposure was demonstrated not only in fluids subjected to direct irradiation, but also in fluids from organs located far from the irradiation zone, providing evidence of one of the potential mechanisms behind the proven systemic effect of PBM (Mikhaylov, 2015).
In a systematic review, it can be concluded that there is sufficient evidence about the beneficial effect of PBM on unstimulated salivary flow and other salivary parameters. However, there is not enough evidence to prove that the effects of PBM are long-lasting enough to improve patients’ quality of life (Golez, 2022).
It was observed that laser therapy has good acceptance in the dental field, where it has been widely used in xerostomy conditions, due to its positive tissue biomodulation effects (Loncar, 2011). The advantages of PBM known to date include improvement in epithelial cell mitosis, enlargement of salivary ducts and stimulation of protein synthesis in submandibular glands (Abueva, 2022), in addition to low-intensity laser therapy being effective in reducing mucosal inflammation. oral, being important in the treatment of hyposalivation (Oliveira, 2022).