In a study of nearly 1,200 children between the ages of 4 and 5, Mexican researchers found that those who were bottle-fed, used pacifiers or sucked their thumb before the age of 1 were more likely to have a posterior crossbite -- where the upper teeth in the back of the mouth bite down behind, rather than in front of, the lower teeth.

Nasal allergies, bottle-feeding and thumb sucking may all contribute to certain types of tooth misalignments in young children, a study shows.

Similarly,Kids can get nosebleeds once in a while or more often. The nosebleeds that are most common in kids usually occur near the front of the nose, on the wall separating the two sides of the nose (the septum), and usually start from just one nostril. children with nasal allergies were more likely to develop an open bite, in which the top and bottom teeth in the front of the mouth do not connect when the jaw closes.

In fact, you may be surprised to know that 45% of 2-year-olds suck their thumbs, probably as a way to cope with stress or anxiety. Thumb sucking can remind a child of the comfort linked to feeding during infancy.Sucking on a pacifier is completely natural; just as with thumb sucking, many children form the habit when they're babies. It calms and soothes them and makes them feel secure well into the toddler years. Sucking on a pacifier may make difficulties worse because it locks his mouth in an unnatural position, making it hard for him to develop and strengthen his facial muscles normally.

Mothers often find that it is easier to just breast-feed. Frequent changes from breast-feeding to bottle feeding can confuse the baby. It's easier for the baby to draw milk from a rubber nipple than from the breast. Also, a mother's milk supply decreases if she does not breast-feed often. Waiting 2-3 weeks to bottle-feed gives the mother time to establish a good milk supply. However, an occasional feeding with expressed milk or formula can be given.

Many studies have linked bottle-feeding, pacifier use and thumb sucking to teeth misalignments, but the evidence regarding allergies has been mixed.

The new findings suggest that all of these factors contribute to teeth misalignment, though only certain types, according to the study authors, led by Dr. Francisco Vazquez-Nava of the Autonomous University of Tamaulipas.

They report the results in the journal Archives of Disease in Childhood.

When babies suck on bottles, pacifiers or their fingers, the muscles of the head and face move differently than they do when breast-feeding. This could hinder the "harmonious" development of the jaw and hard palate, misaligning the baby teeth and possibly the permanent teeth, Vazquez-Nava explained.

In particular, he told Reuters Health, giving babies bottles and pacifiers early in life, and continuing to do so beyond the first year, may interfere with normal development of the dental structures.

Research suggests that about two-thirds of children who suck their thumbs or use pacifiers for at least four months in their first year of life have some form of dental misalignment, Vazquez-Nava said.

With nasal allergies, the misalignment may stem from the tendency of children to chronically breathe with their mouths open and to move the tongue along the roof of the mouth to relieve itching.

The risk of tooth misalignment is one more reason to diagnose and treat allergies sooner than later, Vazquez-Nava said.