First there can be an underlying cause to your tooth erosion. It is a symptom of a tooth that is hitting the other teeth at the wrong time and too often. This can lead to your roots being exposed and make the dentine, which is weaker, become exposed to the attrition of your toothbrush and paste, as the gum moves down the root (see occlusion category) and, unless resolved, your tooth will be under the same stresses as before the repair.
Composites are a standard material used in dentistry. Your concern as to safety would be down to the manufacturer's instructions and contents of the material used. Some composites will tend to stain quicker than others. Another influencing factor will be how well it is applied and polished by the user dentist. This technique is generally cheaper and works quite well in the right hands. In time, if they discolour they can be re-polished and or replaced easily. This material is aesthetic and replaces the use of amalgam for small repairs in teeth.
Small repairs can be done using laboratory made porcelain; they will generally last much longer and do not stain. I would think that this technique would cost the same as a crown or veneer and would probably put you and your dentist off but it is available on request I am sure.