Welcome to JustAnswer, and thank you for putting your trust in me!
Although baking soda may give the impression
of being abrasive, it really is not-- the grittiness is due to the large particle size, but baking soda is really low in abrasivity, and will not harm the teeth.
Because the optical qualities of porcelain (e.g., its translucence, chroma, hue, value, fluorescence, color gradient, and index of refraction) are that of a completely different material than natural tooth enamel
, there will always be some variable degree of optical disparity between your prosthetic teeth and your natural teeth. The only way to completely assure a consistent visual appearance of all the teeth, they must all be covered with a consistent matierial. In other words, for optimal consistency, all your teeth must be restored with porcelain-- either with veneers
or crowns. Ideally, all the front
teeth would be restored at the same time, so that the dental
laboratory technician can fabricate all the restorations
simultaneously, under consistent lighting conditions, to assure a consistent appearance. It is possible to match new porcelain restorations to old restorations, but it is more difficult to do, because it requires that the patient visit the dental laboratory so that the technician can perform the required color matching.
Hope this helps...