why does the toothpaste doesnt react with tube in which its filled?

Answer 1

In fact, toothpaste is NOT inert. NOTHING is inert when placed in the right conditions. Toothpaste tubes are now designed to not react with the toothpaste that they contain. Not to mention, toothpaste has been reformulated to be LESS chemically active. Unfortunately, it's less reactive with teeth, too.

Perhaps you remember those metal toothpaste tubes. They were SO much nicer to use than the present day plastic tubes, because they would stay FLAT when you smashed them down and you could roll them up and they'd STAY rolled up. Unfortunately, the metal foil that these tubes were made of contained lead. The fluoride from the toothpaste actually displaced the lead from the tube (see "electromotive series of elements" for more understanding) and it became bound up in the walls of the tube. If you bought Crest that was just manufactured, it was actually pretty effective - just as the studies said it would be. In reality, though, with the slow distribution channels of the 1950's, Crest tended to take 6 months or so to make it from packaging to the warehouse to the supermarket shelf to the end consumer and by then, much of the fluoride in the toothpaste had been replaced by lead from the tube. Beside not being as effective in preventing cavities as it should have been, it was actually delivering a small dose of lead to the users! Fortunately, most people rinse and spit after brushing, so there was not an epidemic of lead poisoning among the children or conscientious parents everywhere.

Crest Pro Health has returned to using stannous fluoride, in case nobody noticed. Stannous fluoride was the "standard" against which all fluorides were compared. The manufacturers switched to sodium fluoride because it was more stable inside the tube and did not react so much with the composition of the tube. Sadly, it is not quite as reactive with the tooth either. Sodium fluoride is a more stable atom, which means it is harder to split the fluoride away from the sodium, which makes it less available to the tooth enamel. Well, some topical fluoride is better than none, so it still works to reduce cavities. [SIDEBAR: This is why Colgate uses "sodium mono-phosphate fluoride." The sodium-MFP is just a little bit less stable than non-MFP so they think the bioavailability is better. Perhaps it is, but perhaps it is not.]

So to answer your question, toothpaste tubes and toothpaste have BOTH been reformulated to minimize reactions between the two of them.

Answer 2

toothpaste is inert. Plastic that makes up the toothpaste tube is inert. In order for a reaction to occur you have to have a reason (governed by the laws of thermodynamics). Chemical reactions are usually exchange of electrons (oxidation and reduction reactions) and if the two compounds are stable (i.e. have no free electrons to donate or no charges to attract electrons) they will not react.

Answer 3

Toothpaste is inert. My years of experience as a dentist has shown me that even OUT of the tube, the paste is not real likely to have some kind of violent exothermic reaction.

Answer 4

Because the inner side of the tube is designed not to react chemically with the contents (the same for remedies, facial creams etc, not only for tooth paste)

Answer 5

good question who knows