This root is a highly under-utilised superhero of the dental health world. Not only does it naturally reduce the presence of bacteria that cause cavities and gum inflammation, it very effectively, and perhaps counter-intuitively, whitens and de-stains your pearls too. If a more effective natural plant product exists for the whitening of teeth, I do not know of it.
The root I refer to is Curcuma longa or turmeric. Thoroughly chewed in the fresh state, it offers excellent whitening outcomes. Simply source a supply of fresh turmeric from your local farm, farmers market, grocers, supermarket or online vendor. Organic is always preferable, but as turmeric root is not a heavily sprayed agricultural product, conventional turmeric is also fine. Before brushing your teeth, or first thing in the morning, simply pop 7-10g of well rinsed turmeric, whole and unpeeled (peeling is not necessary for these purposes, but you may choose to if you prefer) and begin to chew. Chew for approximately 3-5 mins, or until there is only a small amount of fibre left and spit out the remainder.
If you look in the mirror you may notice that many of your teeth, especially the molars are covered in the sticky, enzymatically active, bright orange turmeric oil that your chewing has released. Because the oil is likely to be unevenly distributed across your teeth, however, the next phase is to take an organic cotton swab (like these) and start distributing the orange turmeric oil over and across each individual tooth, paying particular attention to areas of more prominent staining. You may use an extra swab if need be, to do this. Now wait 10 - 20 minutes for it to sink in and lift up previous staining.
Finally: if the orange turmeric oil was especially prolific, wipe the majority off with some fresh clean, slightly damp swabs (making sure to compost them when finished). A quick rinse and then brush your teeth as usual. Repeat every day or until you are happy with the level of whitening and stain removal. Results can be very marked indeed with just one or two sessions alone. You are most welcome :)