zDuring the first 3 yrs, the damage from the habit is mainly confined to the anterior segment, producing an anterior open bite.
zDamage can be detrimental if the habit is continued beyond the age of 3.5 yrs.
zAfter 4 years of age, the habit becomes strongly established. The damage seen is more significant.
zAfter the eruption of the permanent incisors, the worst amount of damage seen.
z