Histological effects of photobiomodulation on delayed tooth replantation: a systematic review

This systematic review evaluated preclinical studies to assess whether PBM has a more favorable histological response than other treatments used before delayed replantation of avulsed teeth. This review followed the PRISMA checklist and was registered in PROSPERO. MEDLINE (PubMed), Embase, Scopus and Web of Science were searched from their inception to July 14, 2022. Data were independently extracted by two reviewers. Data were collected about species, number of animals, number and type of teeth, groups evaluated, extra-alveolar time, parameters for PBM and other study groups, presence and characteristics of containment, observation time points, evaluation methods, characteristics evaluated, and significant results. The ARRIVE and SYRCLE tools were used to assess the methodological quality and risk of bias (RoB) of the studies. After screening, six studies were included in the review synthesis. Three of the four studies that evaluated root resorption as an outcome found that PBM decreases its occurrence after delayed tooth replantation. A meta-analysis was not conducted because some data were missing in the included studies. Half of the studies evaluating ankylosis found an increase in its occurrence after PBM. Two studies evaluated inflammatory responses and found a reduction of inflammation after PBM. In general, studies had high methodological heterogeneity, intermediate reporting quality and high RoB. Despite the methodological quality and RoB limitations of the studies, the histological responses after delayed tooth replantation were more favourable in the PBM groups. Preclinical studies supported by guidelines should define laser parameters for future clinical studies.