The Effect of Whitening Toothpastes on Surface Roughness of Dental Composites

Objectives: The aim of this in-vitro study was to evaluate the effect of different toothpastes on the surface roughness of four different dental composite materials.
Methods: Four different composite materials [Ceram X & X-Flow (Dentsply DeTrey GmbH), Filtek Supreme XTE and Filtek Silorane (3M ESPE)] were treated with three different toothpastes [two whitening toothpastes: Rembrandt Plus Toothpaste (RP) (Johnson & Johnson GmbH) and Colgate Sensation White (CSW) (Colgate-Palmolive GmbH), and a non-whitening toothpaste: elmex® Intensive Cleaning toothpaste (eIC) in combination with the elmex® Sensitive Toothpaste (GABA GmbH). From each composite material 45 samples (diameter: 4,5mm, thickness: 2mm) were prepared (n=15/toothpaste) and polymerized by using a LED-unit according to the manufacturer’s instructions. After polymerization, the samples were embedded in self-curing acrylic resin and polished (4000 grid). The slurry used for each abrasion cycle (12.5ml) was prepared by using human saliva and the representative toothpaste in a relation 3:1. The abrasion process was performed with a frequency of 200 movements/minute. The surface roughness of each sample was measured by using laser profilometry at three different time periods: T_0: baseline, T_1: after two-weeks tooth-abrasion simulation and T_2: after 12-weeks tooth-abrasion simulation.
Results: The surface roughness of all composite materials was increased by all toothpastes. The effect of toothpastes was material dependent. For Ceram X and Filtek Silorane, the increase of surface roughness was not significant different among the toothpastes (p>0.05) after 2-weeks abrasion. For all composite material/toothpaste combinations the abrasion time had a significant effect on the surface roughness (p<0.05). After 12-weeks abrasion, CSW caused lower increase of roughness compared to the other toothpastes (p<0.05).
Conclusions: All toothpastes increased the surface roughness of the composite materials. Longer abrasion periods resulted in significant increase of the surface roughness suggesting that if the use of such toothpastes is desired then short application periods are recommended.