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Orthodontics Assignment open bite 1
ZAIN IFTIKHAR
Roll no.: 09
Q1: Classify open bite?
Open bite is classified in three ways:
On the basis of the region involved:
o Anterior open bite
o Posterior open bite
On the basis of etiological factors:
o Skeletal open bite
o Dental open bite
On the basis of molar relationship:
o Class I
o Class II
o Class III
On the basis of clinical evaluation:
o Simple open bite
o Complex open bite
o Compound/infantile open bite
o Iatrogenic open bite
Q2: What is Anterior open bite and posterior open bite?
Anterior open bite (AOB):
There is no vertical overlap of the incisors when the buccal segment teeth are in
occlusion.
Posterior open bite (POB):
When the teeth are in occlusion there is a space between the posterior teeth. This
can sometimes be referred to as a lateral open bite (LOB).
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Q3: What is skeletal and dental open bite?
Skeletal open bite:
It is due to skeletal abnormality. It is associated with facial vertical disproportion.
Skeletal open bites with increased vertical proportions are often associated with a
downward and backward rotation of the mandible with growth. It has generally
occlusal contacts only at the molar level with both occlusal planes diverging
anteriorly.
Dental open bite:
Dental open bite is primarily due to reduced incisor dentoalveolar vertical height.
The face proportions may be normal. Associated with anterior tongue thrust
during swallowing and lisping. The occlusal planes in dental open bite usually
diverge from the first premolar forward.
Q4: What are problems faced by open bite patients?
Having an open bite can cause some quite noticeable problems, such as:
Aesthetics:
Self-consciousness if your smile isn’t how you would like
Speech:
A lisp or other speech impediments
Tooth wear:
Increased wear on the back teeth
Eating:
Difficulty eating some foods
Q5: Describe the etiology of open bite?
In common with other types of malocclusion, both inherited and environmental
factors are implicated in the etiology of an AOB. These factors include
skeletal pattern
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soft tissues
habits
trauma
a localized failure of development
In many cases, the etiology is multifactorial, and in practice it can be difficult to
determine the extent to which each of these potential influences has had as the
presenting malocclusions often appear similar. However, a thorough history and
examination, perhaps with a period of observation, may be helpful.
Q6: Describe the effects of thumb sucking and long face patients?
Thumb sucking:
If a persistent digit-sucking habit continues into the mixed and permanent
dentitions, this can result in an AOB due to restriction of development of the
incisors by the finger or thumb. Characteristically, the AOB produced is
asymmetrical (unless the patient sucks two fingers) and it is often associated with
a posterior crossbite due to constriction of the upper arch which is believed to be
caused by cheek pressure and a low tongue position.
After a sucking habit stops the open bite tends to at least partially resolve,
although this may take several months. During this period, the tongue may
continue to come forward during swallowing to achieve an anterior seal and as a
consequence may limit spontaneous AOB correction. In a small proportion of
cases, where the habit has continued until growth is complete, the open bite may
persist.
Long face:
Individuals with a tendency to vertical rather than horizontal facial growth exhibit
increased vertical skeletal proportions. Where the lower face height is increased,
there will be an increased inter-occlusal distance between the maxilla and
mandible. Although the labial segment teeth appear to be able to compensate for
this to a limited extent by further eruption, where the inter-occlusal distance
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exceeds this compensatory ability an AOB will result. If the vertical, downwards,
and backwards pattern of growth continues, the AOB will become more marked.
In this group of patients, the AOB is usually symmetrical and in the more severe
cases may extend distally around the arch so that only the most posterior molars
are in contact when the patient is in maximal interdigitation. The AOB can also
deteriorate with the eruption of the second and third molars and vertical growth.
The vertical development of the labial segments results in typically extended
alveolar processes when viewed on a lateral cephalometric radiograph.
Q7: What are the three effects of vertical maxillary excess?
The three effects are:
incompetent lips at rest
gummy smile
long lower third of the face
Q8: What are the cephalometric features of skeletal open bite?
The following are the cephalometric features of a skeletal open bite:
increased anterior face height and decreased posterior face height
steep mandibular plane with short ramus
increased anterior lower facial height
upper tip of the palatal plane
excessive eruption of maxillary posterior teeth

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Orthodontics Assignment – open bite 1 ZAIN IFTIKHAR Roll no.: 09 Q1: Classify open bite? Open bite is classified in three ways: • On the basis of the region involved: o Anterior open bite o Posterior open bite • On the basis of etiological factors: o Skeletal open bite o Dental open bite • On the basis of molar relationship: o Class I o Class II o Class III • On the basis of clinical evaluation: o Simple open bite o Complex open bite o Compound/infantile open bite o Iatrogenic open bite Q2: What is Anterior open bite and posterior open bite? • Anterior open bite (AOB): There is no vertical overlap of the incisors when the buccal segment teeth are in occlusion. • Posterior open bite (POB): When the teeth are in occlusion there is a space between the posterior teeth. This can sometimes be referred to as a lateral open bite (LOB). Q3: What is skeletal and dental open bite? Skeletal open bite: It is due to skeletal abnormality. It is associated with facial vertical disproportion. Skeletal open bites with increased vertical proportions are often associated with a downward and backward rotation of the mandible with growth. It has generally occlusal contacts only at the molar level with both occlusal planes diverging anteriorly. Dental open bite: Dental open bite is primarily due to reduced incisor dentoalveolar vertical height. The face proportions may be normal. Associated with anterior tongue thrust during swallowing and lisping. The occlusal planes in dental open bite usually diverge from the first premolar forward. Q4: What are problems faced by open bite patients? Having an open bite can cause some quite noticeable problems, such as: • Aesthetics: Self-consciousness if your smile isn’t how you would like • Speech: A lisp or other speech impediments • Tooth wear: Increased wear on the back teeth • Eating: Difficulty eating some foods Q5: Describe the etiology of open bite? In common with other types of malocclusion, both inherited and environmental factors are implicated in the etiology of an AOB. These factors include • skeletal pattern • • • • soft tissues habits trauma a localized failure of development In many cases, the etiology is multifactorial, and in practice it can be difficult to determine the extent to which each of these potential influences has had as the presenting malocclusions often appear similar. However, a thorough history and examination, perhaps with a period of observation, may be helpful. Q6: Describe the effects of thumb sucking and long face patients? Thumb sucking: If a persistent digit-sucking habit continues into the mixed and permanent dentitions, this can result in an AOB due to restriction of development of the incisors by the finger or thumb. Characteristically, the AOB produced is asymmetrical (unless the patient sucks two fingers) and it is often associated with a posterior crossbite due to constriction of the upper arch which is believed to be caused by cheek pressure and a low tongue position. After a sucking habit stops the open bite tends to at least partially resolve, although this may take several months. During this period, the tongue may continue to come forward during swallowing to achieve an anterior seal and as a consequence may limit spontaneous AOB correction. In a small proportion of cases, where the habit has continued until growth is complete, the open bite may persist. Long face: Individuals with a tendency to vertical rather than horizontal facial growth exhibit increased vertical skeletal proportions. Where the lower face height is increased, there will be an increased inter-occlusal distance between the maxilla and mandible. Although the labial segment teeth appear to be able to compensate for this to a limited extent by further eruption, where the inter-occlusal distance exceeds this compensatory ability an AOB will result. If the vertical, downwards, and backwards pattern of growth continues, the AOB will become more marked. In this group of patients, the AOB is usually symmetrical and in the more severe cases may extend distally around the arch so that only the most posterior molars are in contact when the patient is in maximal interdigitation. The AOB can also deteriorate with the eruption of the second and third molars and vertical growth. The vertical development of the labial segments results in typically extended alveolar processes when viewed on a lateral cephalometric radiograph. Q7: What are the three effects of vertical maxillary excess? The three effects are: • incompetent lips at rest • gummy smile • long lower third of the face Q8: What are the cephalometric features of skeletal open bite? The following are the cephalometric features of a skeletal open bite: • • • • • increased anterior face height and decreased posterior face height steep mandibular plane with short ramus increased anterior lower facial height upper tip of the palatal plane excessive eruption of maxillary posterior teeth Name: Description: ...
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