So far the only active ingredient claimed is fluoride – which does no such thing.
In the old days, with only the use of fluoride, I agree that only superficial tooth enamel can remineralize – leaving under it a deeper carious lesion.
The problem is caused by the infection of caries that continues unchecked once bacterial infection enters dentin.
In fact, we have all noticed in such cases that a small channel (sometimes no bigger than a pinhead) exists – a channel that never closes because the flow of “food” from the saliva enters and flows through this channel to support these bacteria under the surface of enamel.
With the use of xylitol – provided it is in adequate dosage and frequency (at least 5 grams a day and at least 5 exposures- preferably after meals) – the bacterial component is eliminated.
When the bacteria die off, it allows the remineralization process to proceed in the deeper tooth layers.
Xylitol will percolate to these bacteria in dentin (just the same way that the salivary liquids feed the carious process) beneath the enamel.
Xylitol then appears to stimulate the remineralization in the deeper enamel and dentin layers – often to promote complete healing.
I tell patients that xylitol heals the “flesh” of the wound and that fluoride health the “skin” of the wound.
I have personally witnessed many deep carious lesions – well into dentin- heal in adult teeth, both occlusally and interproximally.
I am not yet sure the extent that this will work for deciduous teeth – and compliance is always an issue.
I suggest a specific regimen of mouth rinses to support the antibacterial and remineralizing effects of xylitol and fluoride when used simultaneously.
Novamin and MI paste have yet to impress me. The constituents in these expensive products can probably be found in any diet that includes milk and dairy products.
The secret (in my eyes) is the combined use of xylitol and dilute fluoride rinses (+ fluoride varnish if possible).