Oral habits can be classified in several ways, including by their nature (functional, muscular, etc.), cause (physiological, pathological), or degree of compulsiveness. Thumb sucking in particular progresses through three clinical phases: a normal initial phase, a significant phase where intervention may be needed, and a final intractable phase requiring psychological consultation. Theories on thumb sucking include psychosexual, learning/conditioning, and rooting reflex perspectives. Prolonged thumb sucking can result in dental malocclusions like an open bite from upper incisor proclination and lower incisor retroclination. Treatment is most effective during the significant second phase before deviations become permanent.

1. Oral habits

3. Habits - Definition
 Dorland (1957) – Habit can be defined as a fixed or constant practice
established by frequent repetition
 Buttersworth (1961)) – Habit can be defined as a frequent or constant
practice or acquired tendency, which has been fixed by frequent
repetition
 Maslow (1949) – Habit is a formed reaction that is resistant to change
whether useful or harmful, depending to the degree to which it
interferes with the child’s physical, emotional and social functions
 Moyers (1949) – Oral Habits are learned patterns of muscular
contractions, which are complex in nature
 Johnson (1938) – A habit is an inclination or aptitude for some action
acquired by frequent repetition and showing itself in increased facility
to performance and educed power of resistance

4. Habit is an autonomic response to a
situation acquired normally as the
result of repetition and learning,
strictly applicable only to motor
responses. At each repetition the act
becomes less conscious and can
lead to a unconscious habit.

5. Classification of habits
William JAMES (1923) classified habits into:
 Useful Habits
Include habits of normal function, e.g
, .
 Harmful Habits
Includes all habits which exert pressures/stresses against teeth
and dental arches and also

7. KINGSLEY (1956)
 Based on the nature of the habits, Kingsley (1956) classified
habits as:
1. Functional oral habit: e.g. mouth breathing.
2. Muscular habits: Tongue thrusting, cheek/lip biting.
3. Combined muscular habits: Thumb and finger sucking.
4. Postural habits
Chin-propping
Face leaning on hand
Abnormal pillowing.

8. EARNST KLEIN (1971)
 Intentional / Meaningful Habits
Intentional / meaningful habits are caused by a definite
underlying psychological disturbance.
 Unintentional / Empty Habits
A meaniningless habit, has no need for support. They
can be easily treated by reminder appliances.

9. FINN AND SIM (1975)
• 1. Compulsive oral habits
• 2. Non-compulsive oral habits.

10. Compulsive Habits
 An oral habit is compulsive when it has
acquired a fixation in the child to the
extent that he retreats to the practice of
this habit whenever his security is
threatened by events which occur in his
world.

11.  Various etiologies implicated are:
• Rapid feeding patterns
• Too little feeding at a time
• Too much tension during feeding
• Bottle feeding
• Insecurity brought by a lack of love and tenderness by
mother.

12. Non-compulsive Habits
• Non-compulsive habits are the ones that are
easily added or dropped from the child's
behavior pattern as he matures.
• Continual behavior modification causes
release of undesirable habits and addition of
new socially acceptable ones.

13. According to the cause of
the habit
 Physiologic Habits
Those required for normal physiologic functioning, e.g.
nasal breathing, sucking during infancy.
 Pathologic Habits
Those that are pursued due to pathologic reasons e.g.
mouth breathing due to deviated nasal septum (DNS)/
enlarge adenoids.

14. Triad of a habit
 The deleterious effects produced by a habit depends upon three
factors.
Triad of Habit
Frequency
Duration
Intesity

15. • Duration: The time spent indulging in a habit
• Frequency: The number of times the habit is activated in a
day
• Intensity: The vigor with which the habit is performed

16. • Pinkham has added a fourth dimension to the oral habits, i.e. direction
Intensity
Direction (Pinkham)
Frequency Duration

17. DIGIT-SUCKING HABIT
THUMB/FINGER-SUCKING
 DEFINITIONS
• Gellin (1978): Defines digit-sucking as
placement of thumb or one or more fingers in
varying depths into the mouth.
• Moyers: Repeated and forceful sucking of
thumb with associated strong buccal and lip
contractions.

18. SUCKING REFLEX
 Anatomy and Physiology of Sucking
• Engel on direct observation of infants during
the first year of life revealed their organization
to be an oral and clinging one.

19. There are two forms of sucking:
• Nutritive Sucking: This is the sucking mechanism
involved in breast feeding and bottle feeding.
• Non Nutritive Sucking (NNS): is the earliest form
of sucking adapted by child in response to frustration
or anxiety.

20. Theories of thumb
sucking (non-
nutritional sucking)

21. Psychoanalytical theory of psychosexual
development (sigmund freud) 1905
• In 1938, Freud postulated that thumb sucking
is a manifestation of infantile sexuality and the
persistant thumb sucking is a result of
prolonged emotional disturbance and should
not be treated without identfying the
underlying psychological causes.

22. • An infant associates sucking with pleasurable feelings
such as hunger, satiety and being held.
• These events will be replaced in later life by
transferring the sucking action to the most suitable
object available, namely the thumb or fingers.

23. The learning theory
Davidson (1967)
• This theory advocates that non nutritive sucking is an
adaptive response.
• The infant associates sucking with such pleasurable feelings
as hunger, satiety and being held.
• These events are recalled by sucking action of the suitable
objects available, namely the thumb or finger.
• According to this theory there is no underlying
psychological importance to prolonged non-nutritive
sucking.

24. Benjamin’s theory
(1967)
• Benjamin put his hypothesis that thumb sucking arises
simply and mechanistically from the rooting and placing
reflexes seen in all human infants, monkeys and even infra-
primate mammals.
• Rooting reflex is head turning response – if the infant’s
cheek is stimulated by an object he turns towards the
object and opens the mouth.
• This reflex is more common around 3-4 months of age
and disappears in normal infants around 7-8 months of
age.

25. • The rooting reflex is associated with sucking.
• The object in infants at times of hunger is the mother’s
breast.
• Sometimes an infant may place finder accidently toward
cheek (towards mouth) particularly when the child is
hungry or placed in crib when he is devoid of mother’s
breast.

26. Clinical phases of thumb sucking
habit
• Phase I: (normal and sub-clinically significant): This phase
starts from child’s birth and extends up to 3 years of age.
• Ordinarily, the sucking is naturally reduced by itself during
normal development.
• The presence of thumb sucking during this phase is
considered quite normal and usually terminates at the end
of phase one.
• Persistence of the habit beyond this age can lead to various
malocclusions.

27. • Phase II (Clinically significant sucking): This phase extends
from age 3 to 7 years.
• The presence of sucking during this period is an indication that
the child is under great anxiety.
• A firm and definitive program of correction is indicated at this
time.
• Treatment to solve the dental problems should be inititated
during this phase.
• Any deviation produced by thumb sucking will return to
normality if the habit is interrupted.

28. • Phase III (intractable sucking): Any thumb sucking
persisting after child’s fourth year of age presents the
dentist with a problem.
• It alerts the dentist to the underlying psychological aspect
of the habit.
• Psychological consultation is advised during this phase.

29. Effects of thumb sucking
 The type of malocclusion that may be developed in the
thumb sucking is dependent on a number of variables:
1. Position of the digit during sucking
2. Associated facial muscle contraction.
3. Position of the mandible.
4. Facial skeletal morphology.

30. Classical finding of a regular
pattern thumb sucking:
 SKELETAL:
1. High narrow arch palate
2. Prognathic maxilla
3. Retrognathic mandible
4. Open bite tendency

31.  DENTAL
1. Proclined upper incisors
2. Retroclined lower incisors
3. Increased overjet.
4. Anterior open bite
5. Posterior crossbites

32.  SOFT TISSUE
1. Incompetent lips
2. Hypotonic upper lip
3. Hypertonic lower lip and hyperactive mentalis muscle.

35.  OTHER EFFECTS
1. Affect psychological health
2. Deformation of digit
3. Speech defects (lisping)

37.  Induction effects:
1. The child may develop compensatory tongue thrust and
mouth breathing habit as a result of the open bite.