Effectiveness of Diode Laser Treatment in Managing Dentin Hypersensitivity in Vietnamese Adults: A Six-Month Prospective Study

Introduction

Dentinal hypersensitivity is a common dental condition characterized by sharp, transient pain arising from exposed dentin in response to thermal, tactile, osmotic, or chemical stimuli.^1–4 The condition can negatively affect daily comfort, food selection, and oral hygiene practices, thereby impairing quality of life.³ Current understanding of dentinal hypersensitivity is largely based on the hydrodynamic theory, according to which fluid movement within exposed dentinal tubules activates pulpal mechanoreceptors and produces pain. Exposure of dentinal tubules is most commonly related to enamel loss, cervical wear, abrasion, erosion, attrition, or gingival recession.^5,6

Conventional management strategies include desensitizing toothpastes, topical fluoride, varnishes, sealants, and other tubule-occluding agents.^6–9 Although these approaches are widely used and may provide relief for many patients, their clinical effect may be variable, they often require repeated application or prolonged use, and symptom control is not always durable. These limitations have encouraged investigation of adjunctive or alternative chairside therapies for patients with persistent symptoms.¹⁰

Diode lasers, typically operating within the 800–980 nm range, have attracted interest in the management of dentinal hypersensitivity because of their minimally invasive application and their potential biological and thermal effects on exposed dentin and pulpal neural transmission.^11,12 Their photothermal effects can seal exposed dentinal tubules, thereby reducing sensitivity. Proposed mechanisms include reduction of dentinal fluid movement through tubule sealing, modulation of pulpal nerve activity, and stimulation of reparative dentin formation.^13,14 Previous studies have reported promising short-term and medium-term outcomes with diode laser therapy, but the available evidence remains heterogeneous with respect to wavelength, power settings, treatment protocols, comparator groups, and duration of follow-up.^5,15–18

Despite growing international interest in laser-assisted treatment for dentinal hypersensitivity, prospective clinical data from Vietnamese routine practice settings remain limited. In addition, the lack of standardization across treatment protocols makes it valuable to report outcomes associated with specific diode laser settings used in real-world practice.

Therefore, the present study aimed to prospectively evaluate the short- and medium-term changes in dentinal hypersensitivity after a standardized 810-nm diode laser protocol in Vietnamese adults with cervical dentin wear. The null hypothesis was that diode laser treatment would not produce significant changes in VAS pain scores from baseline across the follow-up period.

Materials and Methods

Study Design

This prospective single-arm clinical study was conducted at the Odonto-Stomatology Center of Hue Central Hospital, Hue, Vietnam, to evaluate the short- and medium-term effectiveness of diode laser treatment for cervical dentin hypersensitivity in routine clinical practice. Participants were recruited by convenience sampling during the study period. The study first assessed cervical dentin wear and dentin hypersensitivity in 67 patients. Of these, 57 patients met the eligibility criteria for treatment evaluation, and 180 hypersensitive teeth from these 57 participants were included in the intervention analysis. Because hypersensitivity was assessed at the treated tooth, the primary treatment analysis was performed at the tooth level rather than at the patient level.

The exploratory single-arm design was chosen to document initial clinical outcomes associated with a standardized diode laser protocol in our setting before undertaking a controlled trial.

The study protocol was reviewed and approved by the Institutional Ethics Committee of Hue Central Hospital, Hue, Vietnam. At the time of approval, the committee documented approval in the institutional review record but did not assign a separate reference number for this study. Written informed consent was obtained from all participants before enrollment. All procedures were performed in accordance with the ethical principles of the Declaration of Helsinki.

Participants

Eligible teeth had cervical dentin wear of grades 1–2, clinical dentin hypersensitivity, and no indication for restorative treatment. Patients with acute medical conditions, pregnancy, use of analgesics, anti-inflammatory agents, or sedatives within 72 hours, history of tooth whitening within the previous 6 months, and endodontically treated or restored teeth were excluded. Teeth with pulp disease, periapical disease, or periodontal disease were also excluded from treatment evaluation.

No formal a priori sample size calculation was performed because this was an exploratory prospective clinical study using convenience sampling.

Intervention

Laser treatment was delivered using an 810-nm diode laser at an output power of 0.5 W in continuous-wave mode. The irradiation protocol consisted of 10 seconds of exposure followed by 10 seconds of rest, with the laser tip positioned approximately 1 mm from the tooth surface. After isolation and cleaning with pumice, the exposed dentin was irradiated using a sweeping non-contact motion to ensure uniform coverage of the sensitive cervical area.

Additional parameters such as spot size and energy density were not available in the archived clinical protocol and therefore could not be calculated reliably for retrospective reporting.

Outcome Measures

The primary outcome measure was change in pain intensity assessed using a visual analogue scale (VAS) from 0 (no pain) to 10 (severe pain). Secondary outcomes included patient-reported satisfaction and any adverse effects observed during or after treatment.

Data Collection and Analysis

Pain intensity was assessed using the visual analogue scale (VAS) at baseline (T0), immediately after treatment (T1), and at 1 month (T2), 3 months (T3), and 6 months (T4). Continuous variables were presented as mean ± standard deviation, whereas categorical variables were summarized as frequencies and percentages. Changes in mean VAS scores over time were analyzed using repeated-measures analysis of variance (repeated-measures ANOVA). When the overall time effect was significant, post hoc pairwise comparisons between baseline and each follow-up time point were performed with Bonferroni adjustment. Subgroup analyses according to baseline pain severity (mild, moderate, and severe) were conducted using the same repeated-measures approach. A two-sided p value < 0.05 was considered statistically significant.

Results

Baseline Characteristics of Patients

A total of 67 patients with cervical dentin wear were initially assessed. After eligibility assessment, 57 patients (30 females and 27 males) were included in the treatment evaluation and contributed 180 hypersensitive teeth to the treatment analysis. Cervical dentin hypersensitivity was present in 86.6% of evaluated teeth, whereas 13.4% showed no sensitivity. According to the Smith and Knight classification, score 2 was the most frequent level of cervical wear (42.1%), followed by score 3 (28.2%), score 1 (27.4%), and score 4 (2.3%) (Table 1).

Table 1 Frequency of Cervical Dentin Wear Classified Smith and Knight (n = 340 Teeth)

Before treatment, moderate sensitivity was the most common VAS category (50.4%), followed by mild (25.4%) and severe sensitivity (24.2%) (Table 2). Cold stimulus was the most frequent trigger for dentin hypersensitivity (74.6%), followed by air stimulation (62.7%) and hard food (10.4%) (Figure 1).

Table 2 Distribution of VAS Sensitivity Levels by Age (n = 256 Teeth)

Figure 1 Frequency of triggering stimuli for dentin hypersensitivity.

Reduction in Pain Sensitivity

Mean VAS scores decreased immediately after diode laser treatment and remained lower than baseline throughout follow-up. The average VAS score fell from 4.71 ± 1.89 at baseline to 2.86 ± 1.54 immediately after treatment, corresponding to a 39.5% reduction. The reduction was maintained at 1 month (2.57 ± 1.46; 45.4% reduction), became most pronounced at 3 months (1.46 ± 1.03; 69.0% reduction), and remained clinically improved at 6 months (1.72 ± 1.15; 63.5% reduction) (Figure 2).

Figure 2 Average dentin hypersensitivity levels over the study period according to VAS score.

When stratified by baseline sensitivity level, larger absolute reductions were observed in teeth with more severe baseline pain. Immediately after treatment, the mean reduction in VAS was 0.46 in the mild group, 1.67 in the moderate group, and 3.28 in the severe group (Table 3). At 1 month, the corresponding reductions were 0.95, 1.79, and 3.72, respectively (Table 4). At 3 months, reductions further increased to 1.26, 2.93, and 5.38 (Table 5). At 6 months, the effect remained substantial, with reductions of 0.97, 2.71, and 5.06 in the mild, moderate, and severe groups, respectively (Table 6). Across all evaluated time points, the reductions from baseline were statistically significant (all p < 0.001).

Table 3 Treatment Results Immediately After Treatment According to VAS Score

Table 4 Treatment Results One Month Post-Treatment According to VAS Score

Table 5 Treatment Results at 3 Months According to VAS Score

Table 6 Treatment Results at 6 Months According to VAS Score

Patient Satisfaction

Over 90% of participants reported high levels of satisfaction with the treatment, citing immediate relief and sustained reduction in sensitivity as key benefits. No significant discomfort or adverse effects were reported during or after the procedure.

Adverse Effects

No adverse effects, such as burns or tissue damage, were observed throughout the study period, underscoring the safety of the diode laser treatment protocol.

Discussion

In this prospective single-arm clinical study, diode laser treatment was associated with an immediate reduction in dentinal hypersensitivity, and the improvement was maintained throughout the 6-month follow-up period. Mean VAS scores decreased substantially immediately after treatment, continued to improve at 1 and 3 months, and remained clearly lower than baseline at 6 months. A slightly higher mean VAS score at 6 months compared with 3 months suggests some attenuation of the treatment effect over time, but overall symptom reduction remained clinically relevant.

The majority of evaluated teeth with cervical wear were sensitive, and moderate sensitivity represented the most frequent baseline category. Cold stimulation was the most common trigger, which is consistent with the clinical profile described in previous studies of dentinal hypersensitivity.^19–22 The predominance of Smith and Knight grades 1 and 2 in our cohort indicates that many treated teeth had mild-to-moderate cervical wear, a pattern similar to that reported in earlier observational studies.^23–25

Our findings also suggest that teeth with greater baseline pain experienced larger absolute reductions in VAS score after treatment. This pattern may reflect a greater margin for measurable clinical improvement in severely sensitive teeth, although the absence of a comparator group prevents conclusions about differential efficacy across severity strata. The observed symptom reduction may be explained by several mechanisms proposed in the literature, including partial sealing of exposed dentinal tubules, modulation of nerve transmission, and stimulation of tertiary dentin formation.^21,26–28

Importantly, the results of the present study should be interpreted with caution because there was no sham-treated or active control group. Accordingly, the observed reduction in pain cannot be attributed exclusively to the diode laser intervention. Placebo response, regression to the mean, behavioral changes after treatment, repeated testing effects, and spontaneous fluctuation in symptoms may also have contributed to the improvement. For this reason, our findings should be viewed as preliminary clinical evidence of an association between diode laser treatment and reduced hypersensitivity rather than definitive proof of efficacy.

We have therefore revised the interpretation of our findings to avoid unsupported comparisons with conventional therapies. Although prior publications have suggested that diode laser therapy may provide rapid symptom relief and sustained improvement in some patients, our study did not include a direct comparator such as fluoride varnish, desensitizing paste, or sham irradiation. No comparative conclusion can therefore be drawn from the present data alone.^{5,10,15–18,27–29}

The high level of patient satisfaction and the absence of observed adverse effects support the feasibility and safety of this chairside protocol in routine clinical practice. These findings are clinically relevant because dentinal hypersensitivity is frequently chronic, bothersome, and difficult to manage consistently with home-use products alone. At the same time, patient-reported satisfaction in an uncontrolled study may itself be influenced by expectation and treatment context, and should therefore be interpreted conservatively.

Several limitations should be acknowledged. First, this was an exploratory study based on convenience sampling, and no formal sample size calculation was performed. Second, the analysis was conducted at the tooth level, and because some participants contributed multiple teeth, within-patient clustering was not fully accounted for. Third, although repeated-measures ANOVA was used to assess changes in VAS scores across follow-up time points, more advanced mixed-effects longitudinal models would provide a more robust analytical framework in future studies. Fourth, key technical parameters such as spot size and energy density were not available for retrospective reporting. Fifth, the 6-month follow-up period does not allow conclusions regarding long-term durability. Finally, demographic data were limited, and the study was not designed for subgroup analysis by sex.

Despite these limitations, the study adds prospective follow-up data from a Vietnamese clinical setting and describes outcomes associated with a clearly reported 810-nm diode laser protocol used in daily practice. These findings may help inform the design of future randomized controlled trials with sham or active comparators, longer follow-up, and more rigorous statistical modeling.

Conclusion

Within the limitations of this prospective single-arm study, a single session of 810-nm diode laser treatment was associated with immediate and sustained reduction in dentinal hypersensitivity over 6 months, together with high patient satisfaction and no observed adverse effects. The findings support the potential role of diode laser therapy as a chairside management option for selected patients with cervical dentin hypersensitivity. However, randomized controlled trials with sham or active comparator groups are needed before definitive conclusions regarding efficacy can be made.