Whitening Toothpaste May Worsen Dental Erosion, While Fluoride and Nano-HAP Offer Protection: Study Finds

The study, published in BMC Oral Health, revealed that whitening toothpastes can exacerbate dental erosion by increasing the surface roughness of enamel and dentine. In contrast, the protective efficacy of fluoride-free toothpastes was found to vary significantly depending on their active ingredients, with some formulations offering minimal protection against erosive damage.

The global rise in erosion lesions has driven researchers to explore effective toothpaste formulations capable of protecting tooth surfaces from acid attacks. Despite extensive efforts, there is no clear consensus on which toothpaste ingredients offer the best defense against erosive toothwear. This ongoing uncertainty underscores the need for further studies in this area. To address this gap, researchers from Turkey, Betül Kübra Kurucu Karadeniz & Emel Karaman, set out to assess the preventive effects of toothpastes with various active ingredients on enamel and dentine erosion.

For this purpose, the researchers used ninety recently extracted bovine incisors, separating the crowns and roots and grinding them flat to prepare enamel and dentine surfaces. The specimens were then divided into six groups: Curaprox Enzycal Zero Fluoride (fluoride-free), Colgate Total 12 (1450 ppm NaF), Splat Biocalcium (fluoride-free and Nano-HAP), Colgate ProRelief (1450 ppm NaF and arginine), Sensodyne Repair and Protection (1450 ppm NaF and novamin), and Opalescence Whitening (1100 ppm NaF).

Each specimen was exposed to a demineralizing solution for 2 minutes and artificial saliva for 60 minutes, repeated four times daily over five days. Brushing was performed with a charged toothbrush at the start and end of the erosive cycles. Initial and final surface roughness was measured on the fifth day using a 3D profilometer, with comparisons made using the Wilcoxon test to identify changes in roughness levels following treatment.

The following were the key findings of the study:

• Opalescence Whitening and Curaprox Enzycal Zero Fluoride significantly increased surface roughness in both enamel and dentine compared to baseline.
• These groups exhibited rougher surfaces than all other groups, except for Colgate ProRelief.
• Sensodyne Repair and Protection resulted in the smoothest enamel surfaces.
• Colgate Total 12 led to the smoothest dentine surfaces.
• Enamel samples in the Opalescence Whitening group showed a significantly greater increase in surface roughness compared to dentine samples.

Within the limitations of this in vitro study, the authors concluded that whitening toothpastes increased both enamel and dentine surface roughness, with enamel roughness being significantly greater than dentine roughness in response to whitening toothpastes. Toothpastes containing fluoride, fluoride combined with novamine, and fluoride combined with arginine were effective in dental erosion prevention. The protective effects of fluoride-free toothpastes varied depending on their specific active ingredients.

"Additionally, toothpastes containing Nano-HAP demonstrated potential in preventing erosive tooth wear (ETW) even without fluoride, though fluoride remains the most effective and reliable option. Nano-HAP toothpastes may serve as an alternative for patients who cannot or choose not to use fluoride" the researchers wrote.

Reference:

Karadeniz, B.K.K., Karaman, E. Effects of different toothpastes against erosive tooth wear of enamel and dentine in vitro. BMC Oral Health 24, 1471 (2024). https://doi.org/10.1186/s12903-024-05260-z