Evaluation of the efficacy of sodium fluoride varnish, dentine bonding agent and diode laser in the treatment of dentine hypersensitivity: A clinical and scanning electron microscopic study

Introduction

DH can affect anyone at any age, but it is more common in people in their third and fourth decades. Dentinal hypersensitivity can affect any tooth surface, however it is most common in canines and premolars' buccal cervical region.1 Periodontal pathogenesis, trauma, teeth whitening, professional oral hygiene, acidic foods and beverages, poor oral hygiene practises or incorrect brushing techniques with subsequent gingival recessions, and other variables may all contribute to dentinal hypersensitivity. Even the removal of orthodontic fixed appliances can result in tooth hypersensitivity. DH is rarely caused by only one of the variables listed above, but rather by a mixture of several.2

Dentinal hypersensitivity is caused by three primary mechanisms: direct innervation, Odontoblast receptor, and by the fluid movement/hydrodynamic theory. In direct innervation theory, nerve endings enter dentine and extend to the dentino-enamel junction. According to the odontoblast receptor theory, odontoblasts act as receptors and send impulses to nerve terminals. Dentinal pain is caused by a hydrodynamic mechanism, or fluid force. The presence and flow of the fluid within the dentinal tubules is the basis for this theory. Nerve endings at the end of dentinal tubules or at the pulp–dentine complex are activated by this centrifugal fluid movement.3 Traditional DH treatments involve the application of a desensitising agent either professionally or at home. Protein precipitants, tubule occluding agents, and tubule sealants are the commonly used agents. Other treatments include iontophoresis and the application of steroid suspension to the root surface to reduce dentin hypersensitivity.4

Hence, this study aimed to evaluate the efficacy of laser and desensitizing agent in the treating dentine hypersensitivity and also to compare the efficacy of laser and desensitizing agent on dentin tubule occlusion by scanning electron microscopy.

Materials and Methods

The research was split into two parts: in vitro and in vivo. For the in vitro phase, 40 extracted anterior teeth were used. The outpatient department (OPD) of Seema Dental College and Hospital was used to recruit 30 individuals aged 20 to 50 years who had a primary complaint of sensitivity to hot and cold for the in vivo study.

Results

The demographic details of participants enrolled for the study are summarized in Table 1.

Distribution of mean visual analogue score of group A, B and C at Baseline, 1 Month and 3 Months. (Table 2)

The mean VAS score was recorded at Baseline, 1 month and 3 months was compared between Group A, Group B and Group C using the one-way ANOVA test. The mean VAS score at baseline was 7.30±2.40, 5.90±1.72 and 6.80±2.34 in group A, B and C respectively. The mean VAS score at 1 month was 4.10±2.64, 4.00±1.73 and 1.70±2.21 in group A, B and C respectively. The mean VAS score at 3 months was 3.11 ±2.14, 3.11±1.83 and 0.70±1.33 in group A, B and C respectively. There was a statistically significant difference in mean VAS score at 3 months between Group A, Group B and Group C.

Comparision of Mean visual analogue score of group a, b and c at baseline, 1 month and 3 months. (Table 3) The inter-group comparison of mean VAS score at Baseline, 1 month and 3 months was done using the Post-hoc Dunnett T3 test. The mean VAS score at 3 months was satistically significant among Group A and Group B compared to Group C. (p<0.05)

Distribution of mean verbal rating scale score of group a, b and c at baseline, 1 month and 3 months. (Table 4)

The mean VRS score was recorded at Baseline, 1 month and 3 months was compared between Group A (Fluoride Varnish), Group B (Dentin Bonding Agent) and Group C (Laser) using the one-way ANOVA test. The mean VRS score at baseline was 3.70±1.25, 3.30±0.80 and 3.60±1.07 in group A, B and C respectively. The mean VRS score at 1 month was 2.10±1.37, 2.33±1.15 and 1.10±1.19 in group A, B and C respectively. The mean VRS score at 3 months was 1.77 ±1.09, 1.66±1.00 and 0.40±0.69 in group A, B and C respectively. There was a statistically significant difference in mean VRS score at 3 months between Group A, Group B and Group C.

Mean diameter of dentinal tubules under sem of control group, fluoride, dentin bonding agent and laser (Table 5, Table 6)

The mean diameter of dentinal tubues was seen under SEM (In vitro) was compared between Control group (Figure 1), Group A (Figure 2), Group B (Figure 3) and Group C (Figure 4) using the one-way ANOVA test. The mean diameter was 5.43±2.30, 2.03±0.62, 1.62±0.37 and 0.68±0.29 for control, group A, group B, group C respectively. There was a satistically significant difference in mean SEM study (In vitro) between Control group, Group A, Group B and Group C. The inter-group comparison of SEM study (In vitro) was done using the Post-hoc bonferroni test. The mean of dentinal tubules in SEM study (In vitro) was significantly more among Control group compared to Group A and Group B which was significantly more than Group C.

Figure 1

Control group

Figure 2

Fluoride group

Figure 3

Dentin bonding group

Figure 4

Laser group

Discussion

Dentinal hypersensitivity is a common clinical condition caused by exposure to dentin.

In reaction to certain stimuli, exposed dentinal tubules emit short, acute pain. Females are thought to have a higher rate of dentine hypersensitivity than males. Dentinal hypersensitivity is typically treated with physical or chemical therapy. The agents work by occluding the tubule, which restricts fluid passage, or by altering the neurological response to pain stimuli.5

Fluoride varnish seem to work by decreasing dentinal permeability by formation of calcium fluoride crystals inside the tubules of the dentinal tubules. Saliva dissolves these crystals to some extent.6 Dentin bonding agents reduce dentinal hypersensitivity by occluding the tubules in the dentin.7 The laser affects the dentinal tubules, which alters neural transmission. Lasers may also coagulate proteins inside dentinal tubules, limiting fluid passage, according to certain theories.8

In the present study on intergroup comparsion, the mean VAS score at 3 months was satistically significant among Group A (Fluoride Varnish) and Group B (Dentin Bonding Agent) compared to Group C (Laser). A study conducted by Gupta J et al9 to compare the effectiveness of diode laser and fluoride varnish. The diode laser and fluoride varnish resulted in reduction in VAS score. After 15 days both the treatment.

modalities were effective and the effectiveness was maintained all through 60 days. However, at the end of the 60th day, the efficacy of fluoride varnish had started to decrease, but diode laser continued to show significant efficacy in lowering DH. A similar result was reported in a study conducted by Jain PR et al10 on the comparison of fluoride varnish and laser, as well as in a clinical trial conducted by Aghanashini S et al,11 which indicated a drop in VAS score when compared to fluoride and laser. Low-power laser therapy for DH is an effective treatment option for promoting biomodulatory effects, reducing pain, and decreasing inflammatory processes. Agarwal PK et al12 found statistically significant reduction in dentine hypersensitivity when laser and dentine bonding agent were used. Laser showed greater clinical efficacy over dentin bonding agent. This significant decrease in dentin hypersensitivity score after laser therapy might be due to biostimulation and interference with neural transmission in the dental pulp. Similarly the significant decrease in dentin hypersensitivity score after dentin bonding agent thereby might be due to occlusion of dentinal tubules due to formation of resin tags. Same results were found in a study conducted by Praveen R et al.13 Ahmed J et al14 conducted a study to compare dentin bonding agent and fluoride varnish in which dentin bonding agent showed significant reduction in VAS score. Mazur M et al15 did a study to evaluate the clinical effificacy of a in-office application of a fluoride varnish and a bonding resin. Both treatment reduced pain intensity. Fluoride varnish showed better results in reducing dentine hypersensitivity.The mean VRS score at 3 months was statistically significant among Group A (Fluoride Varnish) and Group B (Dentin Bonding Agent) compared to Group C (Laser). Pantuzzo ES et al16 observed that using a laser and fluoride varnish reduced dentine hypersensitivity on the VRS score by a statistically significant amount. Diode laser therapy was found to be more effective than fluoride therapy in lowering DH. Similar results were demonstrated by Pesevska et al17 who observed the reduction of DH in 86.6% of the individuals treated with diode laser and 26.6% of individuals treated with fluoride.

In vitro study the mean SEM was significant among Control group compared to Group A (Fluoride Varnish) and Group B (Dentin Bonding Agent) which was significant than Group C (Laser). A study conducted by Corneli R et al18 showed similar result as in this study in which laser showed 100% occluded tubules followed by fluoride varnish while the control group showed completely open tubules. In a study comparing laser and fluoride, Tosun S et al19 found that laser application improved tubular occlusion capacity. After using a diode laser, Umana M et al20 obtained a similar result. DH is an oral condition that has a severe influence on people's quality of life.

Conclusion

According to the findings of this study, sodium fluoride varnish, dentine bonding agent, and laser are all effective in reducing dentine hypersensitivity in vivo, with laser having the best effects. In an in vitro study, the laser group showed a greater reduction in mean diameter of dentinal tubules when compared to sodium fluoride varnish, dentine bonding agent, and the control group.

Source of Funding

None.

Conflict of Interest

The authors declare no conflict of interest.