• Habit as quoted by ‘Hogeboon’ and attributed by
Salder is the methodical way in which mind and
body act as a result of the frequent repetition of
a certain definite sets of nervous impulses.
• Fixed or constant practice established by frequent
• Frequent or constant practice or acquired tendency,
which has been fixed by frequent repetition
• Habits are learnt pattern of muscle contraction of a
very complex nature
CHACKER FM (1961)
Defined mouth breathing as a prolonged or continued
exposure of the tissues of anterior areas of mouth to the
drying effects of inspired air.
Merle (1980) - Suggested the term oro - nasal breathing
instead of mouth breathing
a) Lowering of the mandible.
b) Positioning of the tongue downwards and
Lowering of the tongue and mandible upsets the
orofacial equilibrium. There is an unrestricted buccinator
activity that influences the position of the teeth and also
the growth of jaws.
• Oral habits have a definite bearing on the
development of occlusion.
• One may acquire certain habits that may either
temporarily or permanently be harmful to dental
occlusion and to the tooth supporting structures.
• So, such habits should be identified and treated
as soon as possible.
• Harmful oral habits include :
1.Finger or thumb sucking
4.Cheek / Lip biting
• Etiology of mouth breathing is:
1) Rhinitis and Sinusitis
2)over eruption of lower incisors touching
the palatal mucosa
3)deviated nasal septum
4)all of the above
• Due to habit of mouth breathing:
1) lower lips become hyperactive
2) upper lips become hypoactive
3) both lips become hypoactive
4) upper lips become hyperactive
• Orthodontics the art and science
• Text book of pedodontics