Effects of low-level light therapy on dentin hypersensitivity: a systematic review and meta-analysis

Abstract

Objective: To investigate the treatment efficacy of low-level light therapy on dentin hypersensitivity.

Materials and methods: Following the PRISMA guideline, six electronic databases supplemented with bibliographies were searched till December 2020. Two reviewers performed the screenings independently with a reliability assessment. Studies fulfilling the pre-registered eligibility criteria were included for risk-of-bias assessment and data synthesis.

Results: Thirty-five articles ultimately informed this systematic review based on the eligibility criteria and underwent risk-of-bias assessment (ĸ = 0.86). Quantitative results were deduced by meta-analysis of 20 randomised controlled trials: LLLT showed favourable outcomes compared to placebos for immediate (SMD: 1.09, 95% CI: 0.47 to 1.70), interim (SMD: 1.32, 95% CI: 0.41 to 2.23), and persistent efficacies (SMD: 2.86, 95% CI: 1.98 to 3.74). However, substantial heterogeneity existed among included studies (I²: 64-95%). Regarding comparisons with other desensitising strategies, LLLT showed no significant benefits in DH alleviation over others except fluorides for interim efficacy (SMD: 0.31, 95% CI: 0.10 to 0.52) and persistent efficacy (SMD: 0.45, 95% CI: 0.03 to 0.86).

Conclusions: This systematic review shows that LLLT has positive immediate, interim, and persistent DH-treatment efficacies compared with placebo. No superior treatment effects of LLLT were observed except fluoride agent use. Further studies are warranted-RCTs with low risk of bias, consistent technical settings, comprehensive assessments, and long follow-up periods.

Clinical relevance: This systematic review bridges a critical research gap by analysing clinical evidence in the DH-alleviating efficacy of LLLT in comparison with placebo and other in-office desensitising strategies.

Keywords: Dentin hypersensitivity; Low-level light therapy; Meta-analysis; Systematic review.

Fig. 1

PRISMA flow diagram

Fig. 2

Risk-of-bias assessment of twenty-seven randomised controlled trials (RCTs) with A Revised Cochrane Risk-of-Bias Tool for Randomized Trials (RoB 2)

Fig. 3

Risk-of-bias assessment of eight non-randomised controlled trials (NRSs) with Risk of Bias Tool in Non-Randomized Studies – of Interventions (ROBINS-I)

Fig. 4

Forest plots indicating treatment efficacy of LLLT on DH alleviation compared to placebo effect: A immediate efficacy; B interim efficacy; C persistent efficacy

Fig. 5

Forest plots indicating treatment efficacy of LLLT on DH alleviation compared to fluorides: A immediate efficacy; B interim efficacy; C persistent efficacy

Fig. 6

Forest plots indicating treatment efficacy of LLLT on DH alleviation compared to adhesives: A immediate efficacy; B interim efficacy; C persistent efficacy

Fig. 7

Forest plots indicating treatment efficacy of LLLT on DH alleviation compared to potassium compounds: A immediate efficacy; B interim efficacy; and to dentifrices for C immediate efficacy; D interim efficacy