Photobiomodulation and salivary glands: a systematic review

To date, there is no compilation of evidence-based information associating photobiomodulation effect and salivary glands. This systematic review aims to assess photobiomodulation effect of low intensity laser on salivary glands in the presence of systemic diseases. MEDLINE databases were searched in duplicate through December 2018. In vivo studies and clinical trials were included if photobiomodulation was performed in salivary glands of animal (rat or mice) or human in the presence of systemic disease. The methodological quality was assessed in duplicate using the modified Newcastle-Ottawa scale (NOS). Search strategy identified 483 potentially eligible articles, and 449 were included. The Boolean search naturally leads to a high amount of works the majority of which were excluded because the analysis of the title and abstract demonstrated it was not focusing on PBM. Only 34 studies were selected for the full-text analysis, of which 5 were excluded due to non-use of photobiomodulation, 4 due to lack of control group, 2 because they were studies of cell cultures and 1 because they did not have the total of animals used. Thus, 21 papers were included for the critical evaluation of the impact of photobiomodulation on the major salivary glands; the studies used rats (n = 10) and humans (n = 11). Although studies reported an increase in the salivary rate, decrease in pain, and increase in quality of life after the PBM, the lack of standards for the application of light and reporting of the parameters, make it hard to reproduce the results. This topic is still in need for further research.