White spots appearing on an infants teeth may be related to conditions that occurred during the gestation period, usually a fever experienced by the mother. It is linked to the maturation phase of the enamel as the crystal forms within the teeth. It starts as soft tissue cells, then Calcium and minerals (hydroxyapetate) forms by the cells – some make enamel and some make dentine ( the yellow core of the tooth). The late stage of maturation is the removal of water from the crystal to solidify it. If there is a fault in any stage of this process then white or yellow spots appear. Fluoride that becomes embedded in the matrix creates a different kind of enamel called fluoroapetate which is much tougher than hydroxyapetate and therefore more resistant to decay.