To evaluate the effectiveness of
low-level laser therapy (
LLLT) in the treatment of
xerostomia in primary Sjögren's syndrome (SS), a randomized clinical trial of patients with dry mouth symptoms associated with primary SS receiving care at a university hospital was conducted. Sixty-six patients were randomly assigned with a 1:1 allocation ratio to receive
LLLT (
laser group, n = 33) or placebo treatment (placebo group, n = 33). Patients in the
laser group received
LLLT twice a week for 6 weeks, for a total of 12 treatment sessions.
Laser irradiation was performed with an
aluminum-
gallium-arsenide laser diode at a wavelength of 808 nm, 100-mW output power, and energy density of 4.0 J/cm2 per irradiation point per session. Placebo treatment was performed following the same protocol used for irradiated patients and using the same
laser device to mimic a real irradiation, but with no active
laser emission and the tip of the
laser probe covered with
aluminum foil. The outcomes of interest were
xerostomia inventory scores, salivary flow rate, salivary beta-2 microglobulin levels, and salivary
sodium and
chlorine concentrations. Patients in both groups showed no improvement in
xerostomia. Likewise, there was no significant improvement in
xerostomia inventory scores (p = 0.301) or salivary flow rate (p = 0.643) in either group. There was no difference in salivary beta-2 microglobulin levels,
sodium concentration, and
chlorine concentration before and after intervention or between the two groups. The
LLLT protocol used in this study effected no improvement in
xerostomia or salivary flow rate in patients with primary SS. ClinicalTrials.gov Identifier: NCT02066896.