This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

1. To evaluate the effects of water fluoridation (artificial or natural) for the prevention of dental caries.

2. To evaluate the effects of water fluoridation (artificial or natural) on dental fluorosis.

The original systematic review (McDonagh 2000) included five objectives. For the purposes of the current review, the original objectives 1 to 3 will be covered by objective 1 (above). The fourth objective will be covered by objective 2 (above) and the fifth objective which explored the differential effects of natural and artificial fluoridation is not covered in the current review.