Editing Toothpaste (section)

===Whitening toothpastes===
Many toothpastes make whitening claims. Abrasion is the principal way that toothpaste removes stains, and toothpastes that are not marketed as whitening can still remove stains by abrasion.<ref name="The New York Times-2022"/> Some of these toothpastes contain peroxide, the same ingredient found in tooth bleaching gels. Whitening toothpaste cannot alter the natural color of teeth or reverse discoloration by penetrating surface stains or decay. To remove surface stains, whitening toothpaste may include abrasives to gently polish the teeth or additives such as [[sodium tripolyphosphate]] to break down or dissolve stains. When used twice a day, whitening toothpaste typically takes two to four weeks to make teeth appear whiter. Whitening toothpaste is generally safe for daily use, but excessive use might damage tooth enamel.<ref>{{cite web | vauthors = Salinas TJ | url = http://www.mayoclinic.com/health/whitening-toothpaste/AN01818 | title = Whitening toothpaste: Does it actually whiten teeth? | work = Mayo Clinic | url-status = live | archive-url = https://web.archive.org/web/20080503211651/http://www.mayoclinic.com/health/whitening-toothpaste/AN01818 | archive-date = May 3, 2008 | df = mdy-all }}</ref> A recent systematic review in 2017 concluded that nearly all dentifrices that are specifically formulated for tooth whitening were shown to have a beneficial effect in reducing extrinsic stains, irrespective of whether or not a chemical discoloration agent was added.<ref>{{cite journal | vauthors = Soeteman GD, Valkenburg C, Van der Weijden GA, Van Loveren C, Bakker E, Slot DE | title = Whitening dentifrice and tooth surface discoloration-a systematic review and meta-analysis | journal = International Journal of Dental Hygiene | volume = 16 | issue = 1 | pages = 24–35 | date = February 2018 | pmid = 28573755 | doi = 10.1111/idh.12289 | hdl = 11245.1/70dfdb36-d5af-412c-8032-423c258f89cf | s2cid = 3848563 | url = https://pure.uva.nl/ws/files/65470544/Front_matter.pdf | hdl-access = free }}</ref> However, the whitening process can permanently reduce the strength of the teeth, as the process scrapes away a protective outer layer of enamel.<ref>{{cite web|url=http://sciencefocus.com/qa/are-yellow-teeth-stronger|title=Are yellow teeth stronger?|work=sciencefocus.com}}</ref>