Dentin Hypersensitivity Relief: A Systematic Review and Meta-Analysis

Dentin hypersensitivity (DH) is a common condition affecting 25-35% of adults, characterized by sharp dental pain triggered by external stimuli. While not life-threatening, Dentin Hypersensitivity significantly impacts oral health, functionality, and quality of life. Current treatments include at-home desensitizing toothpaste, which offers gradual relief, and professional interventions such as varnishes, restorative materials, nerve desensitizers, light therapy, and periodontal surgery. However, no treatment fully meets the ideal criteria of being rapid, permanent, comfortable, and non-pigmenting. Despite the variety of options, there is no consensus on the most effective professional treatment or application technique. This highlights the need for further research to optimize Dentine hypersensitivity management strategies.

This study systematically evaluates the efficacy of low-level laser therapy (LLLT) in managing dentin hypersensitivity (DH), a condition characterized by pain from external stimuli. By analyzing data from 27 randomized controlled trials (RCTs) and 8 non-randomized studies (NRSs), researchers focused on patient-reported outcomes using visual analogue scales (VAS). Employing rigorous methodologies, including systematic literature review, risk-of-bias assessment, and meta-analysis, the study found LLLT significantly reduced DH compared to placebos, with energy density positively influencing outcomes. However, substantial heterogeneity and limited low-bias studies necessitate cautious interpretation. The findings support LLLT as a promising intervention, advocating for standardized protocols and further research to optimize its clinical application.

https://pubmed.ncbi.nlm.nih.gov/34642786/

DOI: 10.1007/s00784-021-04183-1 

This study aims to evaluate the efficacy of low-level laser therapy (LLLT) in treating dentin hypersensitivity (DH) by analyzing scores from patients in response to various external stimuli, such as thermal and chemical triggers. The evidence was gathered from multiple randomized controlled trials (RCTs) and non-randomized controlled studies (NRSs). The researcher team utilized EndNote X9.3.3 for literature management, systematically screening studies based on eligibility criteria and resolving discrepancies through reviewer discussions. Inter-reviewer reliability was confirmed with Cohen's κ-values, maintaining an acceptable threshold (κ ≥ 0.6).

Data extraction encompassed details about general information, participants, interventions, comparators, and assessments of outcomes, primarily focusing on patient-reported scores on a visual analogue scale (VAS). Risk-of-bias assessments were performed using the Cochrane Handbook’s tools tailored for both RCTs (RoB 2) and NRSs (ROBINS-I). Each study was rated on a spectrum from low to high risk of bias, ensuring a rigorous evaluation.

The data synthesis involved quantitative analyses of results from RCTs and NRSs deemed low risk of bias. The primary outcome measure was the change in Dentin Hypersensitivity scores reported by patients after LLLT sessions, highlighted across immediate follow-ups and at intervals extending to six months. All numeric scale data were standardized to VAS scores to facilitate comprehensive meta-analysis. This methodological framework allowed researchers to pool standard mean differences from individual studies, utilizing a random-effects model to factor in variances.

The analysis, executed through RevMan5.4, included statistical assessments of heterogeneity, yielding forest plots and a summary-of-findings table elucidating LLLT’s effectiveness. A multiple meta-regression was also conducted to explore the treatment's efficacy while adjusting for various study-related factors. The collective results offer valuable insights into LLLT as a potential intervention for alleviating Dentin Hypersensitivity.

The electronic search across six databases, complemented by manual searching, initially yielded 1,558 records. After removing duplicates, 1,387 records were screened according to the pre-registered eligibility criteria, resulting in 99 articles selected for full-text assessment (κ = 0.78). Ultimately, 64 studies were excluded, leading to the inclusion of 35 articles in qualitative synthesis, comprising 27 RCTs and 8 NRSs. For quantitative synthesis, 20 RCTs were analyzed, with 8 NRSs excluded due to a moderate-to-serious risk of bias.

The included studies involved participants of both sexes, ranging from 12 to 70 years old. The interventions centered on diodes and Nd: YAG lasers, applying various parameters:

• Wavelength: 630-1067 nm
• Output Power: 1.5-1000 mW
• Total Dosage: 0.1-300 J
• Energy Density: 2-100 J/cm²
• Exposure Time: 10-180 s
• Irradiation Sessions: 1-6

Twelve studies compared LLLT to placebos, with others involving fluorides, adhesives, potassium nitrate, and dentifrices. Most assessed Dentin Hypersensitivity via VAS and other numeric scales, including 3-point, 4-point, and 5-point scales.

The assessment of risks of bias in the 27 RCTs revealed:

• 9 studies had a high risk of bias (primarily from outcome measurements).
• 12 studies had some concerns regarding bias.
• 6 studies displayed a low risk of bias across all domains.

For the 8 NRSs, one was rated with a moderate risk of bias, while seven showed a serious risk of bias.

Quantitative analysis was limited to studies using air blast stimuli, with 18 studies employing VAS scores. The results indicated significant efficacy of LLLT compared to placebo:

• Immediate Efficacy (SMD): 1.09 (95% CI: 0.47 to 1.70, p < 0.001)
• Interim Efficacy (SMD): 1.32 (95% CI: 0.41 to 2.23, p = 0.005)
• Persistent Efficacy (SMD): 2.86 (95% CI: 1.98 to 3.74, p < 0.001)

Statistical heterogeneity was observed with I² values:

• Immediate Efficacy: 92%
• Interim Efficacy: 95%
• Persistent Efficacy: 64%

Correlation with Energy Density

A meta-regression identified that energy density significantly correlated with immediate (R² = 34.71%) and interim (R² = 60.11%) efficacy. An increase in energy density was associated with a 0.213 decrease in VAS scores for immediate efficacy and a 0.166 decrease for interim efficacy.

Comparisons with Other Desensitization Strategies

Compared to various agents:

• Fluorides: No significant immediate efficacy (SMD: 0.11, 95% CI: -0.31 to 0.54, p = 0.60), but slight advantages in interim (p = 0.003) and persistent efficacy (p = 0.03).
• Adhesives, Potassium Compounds, Dentifrices: No statistically significant differences in Dentin hypersensitivity alleviation at any stage (SMDs between −0.02 to 0.19; p > 0.05).

The findings emphasize the need for cautious interpretation due to substantial heterogeneity and limited studies with low risks of bias.

In conclusion, this study underscores the potential of low-level laser therapy (LLLT) as an effective treatment for dentin hypersensitivity, based on patient-reported outcomes measured through visual analogue scales (VAS). The rigorous assessment of studies, alongside thorough risk-of-bias evaluations, adds credibility to the findings. With the accumulation of data supporting LLLT's efficacy, these results advocate for its inclusion in clinical practices addressing Dentin hypersensitivity. Future research should focus on standardizing treatment protocols and expanding understanding to optimize outcomes for diverse patient profiles, thereby enhancing the overall effectiveness of LLLT in dental care.