Efficacy of GuruNanda® Teeth Whitening Strips – Professional: An In-Vitro Evaluation of Dental Cleaning and Whitening Performance

An in-vitro evaluation of dental cleaning and whitening performance

Objective

The objective of this in-vitro evaluation was to determine the dental cleaning and whitening efficacy of GuruNanda® Teeth Whitening Strips – Professional compared with a de-ionized water control, using a simulated extrinsic staining model on bovine enamel. The study assessed changes in enamel lightness (L*) and color gradation (BG*) before and after treatment using a VITA Easyshade V colorimeter, in accordance with internationally accepted standards for dental material testing.

Process

Healthy bovine incisors were sectioned into standardized enamel blocks (5 × 5 × 2 mm), embedded in resin, polished, and acid-etched. To simulate extrinsic discoloration, specimens were immersed for 48 hours in a standardized mixed-dye solution containing coffee, red wine, soy sauce, and black tea.

The study consisted of two groups:

  • Test Group (A): GuruNanda® Teeth Whitening Strips – Professional
  • Control Group (C): Filter paper soaked in de-ionized water

Each group included eight enamel blocks. Baseline measurements of lightness (L* before) and shade guide values (BG* before) were obtained using a VITA Easyshade V colorimeter. Each treatment involved a simulated 60-minute product contact, followed by post-treatment measurements (L* after, BG* after). This protocol was repeated daily for 14 days, with enamel blocks stored in artificial saliva between treatment sessions.

Evaluation parameters included the change in whiteness (ΔL* = L* after − L* before) and the change in color gradation (ΔBG* = BG* after − BG* before). Statistical analyses were conducted using paired and independent-sample t-tests (SPSS v26), with significance defined as p < 0.05.

Results

Table 1. Change in Enamel Lightness (L*) Before and After Each Treatment

Day L* Value (A) ΔL* (A) L* Value (C) ΔL* (C) p-Value (A vs C)
0 44.99 ± 2.86 — 44.70 ± 2.80 — —
1 56.85 ± 5.76 11.86 ± 3.86 45.65 ± 5.64 0.95 ± 4.76 < 0.001
2 69.69 ± 4.80 24.70 ± 3.76 52.14 ± 5.65 7.44 ± 4.25 < 0.001
3 76.09 ± 3.61 31.10 ± 3.24 54.58 ± 4.13 9.88 ± 3.24 < 0.001
4 78.40 ± 4.10 33.41 ± 3.49 54.69 ± 6.17 9.99 ± 4.55 < 0.001
5 80.26 ± 4.60 35.28 ± 3.41 55.43 ± 4.97 10.73 ± 4.61 < 0.001
6 82.39 ± 3.38 37.40 ± 2.66 54.74 ± 6.52 10.04 ± 5.21 < 0.001
7 82.63 ± 4.73 37.64 ± 4.37 56.48 ± 5.42 11.78 ± 3.87 < 0.001
10 85.38 ± 3.36 40.39 ± 2.82 59.78 ± 3.65 15.08 ± 3.24 < 0.001
14 85.74 ± 4.01 40.75 ± 2.74 62.15 ± 4.79 17.45 ± 4.33 < 0.001
Figure 1. L* value represents enamel brightness; higher values indicate whiter enamel. ΔL* denotes the change in whiteness after each treatment interval.

Table 2. Change in Color Gradation (VITA Bleached Guide 3D-MASTER)

Day BG* (A) ΔBG* (A) BG* (C) ΔBG* (C) p-Value (A vs C)
0 29.00 ± 0.00 — 29.00 ± 0.00 — —
1 29.00 ± 0.00 0.00 ± 0.00 29.00 ± 0.00 0.00 ± 0.00 < 0.001
2 25.63 ± 2.72 −3.38 ± 2.72 29.00 ± 0.00 0.00 ± 0.00 < 0.001
3 21.25 ± 2.60 −7.75 ± 2.60 28.88 ± 0.35 −0.13 ± 0.35 < 0.001
4 18.63 ± 2.20 −10.38 ± 2.20 28.50 ± 1.07 −0.50 ± 1.07 < 0.001
5 16.88 ± 2.59 −12.13 ± 2.59 28.63 ± 1.06 −0.38 ± 1.06 < 0.001
6 14.88 ± 2.30 −14.13 ± 2.30 28.50 ± 1.07 −0.50 ± 1.07 < 0.001
7 14.13 ± 2.42 −14.88 ± 2.42 28.38 ± 1.06 −0.63 ± 1.06 < 0.001
10 11.75 ± 2.25 −17.25 ± 2.25 28.13 ± 1.36 −0.88 ± 1.36 < 0.001
14 10.88 ± 2.75 −18.13 ± 2.75 27.88 ± 1.73 −1.13 ± 1.73 < 0.001
Figure 2. BG* value progression over the 14-day simulation period. Lower BG* values indicate whiter enamel. ΔBG* represents the change in color gradation.
Figure 3. Comparative whitening performance of GuruNanda® Teeth Whitening Strips – Professional versus control, showing progressive enamel brightening across treatment intervals.

Observation

GuruNanda® Teeth Whitening Strips – Professional demonstrated statistically significant whitening activity, producing visibly brighter enamel blocks after a single simulated use. A ΔL* value exceeding 11 points indicated substantial whitening improvement compared with the control (p < 0.001).

Over the 14-day study period, incremental increases in L* values and corresponding decreases in BG* values confirmed a cumulative whitening effect. Visual assessment corroborated instrumental findings, showing consistent brightening following each application.

Conclusion

This in-vitro evaluation confirmed that GuruNanda® Teeth Whitening Strips – Professional deliver high dental cleaning and whitening efficacy by effectively removing extrinsic stains and increasing enamel lightness without compromising surface integrity.

The significant increase in L* values and measurable decrease in BG* values highlight the product’s rapid and sustained whitening potential, supporting its use as a safe, enamel-friendly, and fast-acting professional-grade whitening solution.