A strong association has been found between
exclusive bottle-feeding and malocclusion.
(SOURCE: The Journal of the Canadian Dental Association–1991)
Your Jaws ~ Your Life (page 46)

Backward forces of bottle and pacifier sucking constrict dental arches and jaws, dramatically increasing malocclusions. Sucking forces constrict the palatal bone that holds the teeth, especially in the upper front roof of the mouth area. The forces of sucking oppose normal directions of growth for the upper and lower jaws. This prevents the upper and lower jaws from growing to their full potential during what should be one of the fastest periods of growth. Small upper jaws then prevent the lower jaws from growing and moving forward. The longer and stronger an infant sucks, the more damage is done.
Current baby bottle and pacifier designs do NOT place forces on the jaws (sucking), the same way as breastfeeding (suckling). There is presently no bottle or pacifier nipple like a mother’s breast. Breast suckling helps upper and lower jaws form in 3-dimensional ways that sucking on bottles and pacifiers cannot. Research shows there are lifelong benefits for an infant and a nursing mother from at least 3-6 months of exclusive breastfeeding, including a greater chance for straighter teeth and jaws for the child.