Effects of Daily-Use Whitening Toothpastes on Force Degradation of Orthodontic Elastomeric Chains: An In Vitro Study

This in vitro study evaluated and compared the effects of various commercially available whitening toothpastes on the degradation of force and the surface properties of orthodontic elastomeric power chains (EPCs).

Fifty identical clear EPC segments were randomly divided into five groups (n = 10): Group A (hydrogen peroxide-based), Group B (hydrated silica-based), Group C (activated charcoal-based), Group D (regular toothpaste), and Group E (distilled water control). Specimens were stretched to 25 mm on acrylic jigs and subjected to simulated brushing twice daily for 28 days using toothpaste slurries (1:3 dilution) and were maintained in a thermostatic water bath at 37°C ± 1°C to simulate the oral environment. Force measurements were recorded at baseline, 24 hours, and 7, 14, 21, and 28 days using a digital force gauge. Statistical analysis using mixed repeated-measures ANOVA revealed significant effects of time and toothpaste formulation (p < 0.001). Color stability and surface morphology were evaluated visually and by optical microscopy.

All groups exhibited significant time-dependent force loss (p < 0.001), with the greatest reduction (approximately 55%) occurring within the first 24 hours. Group C (charcoal-based) showed the highest force degradation (75.4% at 28 days), which was significantly greater than that observed in all other groups (p < 0.001). Groups A, B, D, and E demonstrated comparable force loss patterns (approximately 65-68%). Surface roughness and discoloration increased over time, most notably in Groups B, C, and D.

Whitening toothpastes, particularly those containing activated charcoal, significantly accelerate force degradation and surface deterioration of orthodontic EPCs. Peroxide-based whitening toothpastes appear to have a less detrimental chemical effect. Careful selection of oral hygiene products is therefore recommended during orthodontic treatment.