Difrax has 2 different pacifier models, natural and dental. Which one should I buy?

Every child has its own preference. Most babies prefer the Natural model.
The Natural pacifier is shaped in the form of a nipple. Because of its familiar shape it is suitable in combination with breastfeeding. The nozzle of the Natural pacifier is round, so it has no top or bottom. This enables the child to turn it in its mouth.
The Dental pacifier stimulates the development of palate, tongue and jaw muscles. The round side of the nozzle (the sucking part) sits comfortably up against the palate; the flat side presses down on the tongue.