What can I do to strengthen and whiten my teeth? What toothpaste would help the most? (Photos)

It is possible that this is nothing new with you and you are now just noticing.  However, teeth naturally have 3-4 shades, and the incisal edges (tips of the teeth) are more translucent.  Often they become MORE translucent as they get thinner (from grinding or wear and tear).  There is no other solution than a restorative option (porcelain veneers or bonded composite).Bleaching processes require intimate fit of a tray or gel, so whitening strips will always leave the gumline of the teeth only partially treated.  To get your teeth as white as possible, you need the KöR system.  Nothing else comes close.

Hello and thank you for your question. Translucency can be normal as well as color variations. I recommend following up with your Dentist or consult with a Prosthodontist about teeth whitening options. A Prosthodontist is a dental specialist who has advanced training in tooth restoration and whitening. 

The edges of your teeth are naturally translucent. If isn't causing by demineralization and there isn't anything to do change the translucency of your teeth. You could cover it up with bonding or veneers, but I wouldn't suggest that. Translucency of the edges of your teeth is normal. The lower part of the bottom teeth are more yellow because the enamel is thin there and the dentin underneath shows through. Dentin is yellow and isn't going to whiten much. The enamel whitens well, but since it's so thin there, the yellow dentin will always show through. Again, this is normal.