Effect of Sift Tissu Morphology & Behavior

Effect of Sift Tissu Morphology & Behavior 

The soft tissues are- 

Lips

Cheeks

Tongue

Fraenum 

Functions of soft tissues: 

i) The soft tissues are act as a mould in which dento alveolar structure develop.

ii) The lips and cheeks provide buccal force and the tongue provide the lingual force.

iii) They provide positive forces at rest (muscle tone) and active forces during function e.g during swallowing, mastication, speech, expression etc.

Importance of knowing of effect of tissue morphology:

i) It is important to study the morphology and behavior of the lip, cheek and tongue to know their effect on dental arches and occlusion.

ii) Balance force of soft tissue is important for the success of other treatment.

Effects of soft tissue morphology and behavior:

The morphology of lips, cheek and tongue is a part of inherited pattern. But all the behavior are not in born or inherited. Some of those may be adapted in response to the functional needs. Soft tissue morphology and behaviors that may cause mal occlusion are given-

Lips may be of following variety..

A. Competent lips- when lip can maintain anterior oral seal with minimum muscular effort, muscles of facial expression are in relaxed position ands mandible is in endogenous posture is known as competent lips.

Behavior of competent lips:

i) Habitually competent lip- competent lip morphology with lips together. 

ii) Competent lips but habitually apart- 

        -- It is due to-Nasal obstruction.

-- Sometime with no apparent Cause

iii) Potentially competent lips- are competent but it is due to problem in teeth that is produced incisors-

B. Incompetent lips- The lips remain apart when the muscle of facial expression are relaxed position and mandible is in endogenous posture, is known as incompetent lips.

Cause:

It is due to a disproportion between the soft tissues (lips) and bony frame work.

Thus it may be caused by any one or a combination of following-

i) Shortage of lips.

ii) Increased vertical distance between lips

iii) Increased horizontal distance between lips.

iv) Micrognathia.

Behaviors of incompetent lips:  

i) In competent lip morphology in which the lips are habitually held together.

ii) Incompetent lip morphology in which lips are habitually apart.

Effect of Incompetent lips:

         Malocclusion may causes by this incompetent lips are-

i) When lips are moderately incompetent.

ii) The lip seal may be produced by sustained of the circumoral muscles. This may cause-

        (a) Retroclination of incisor teeth.

        (b) Crowding of incisor teeth.

iii) When lips are more incompetent-

Here the lips seal is produced by the contact between the lower lip and tongue in addition to a posterior oral seal.This adaptive postures and behaviors may produce mal relationship of the labial segments.

        a) On a class I dental base case where lip incomplete is not so great, may not produce any                   

                 abnormality expect incomplete over bite. 

        b) On a class II dental base-

 Proclination of upper incisor.

 Even retroclination of lower incisors.

These will produce- increased over jet and increased but incomplete overbite.

Fig: 1. Competent lip; 2. Incompetent lip; 3. Potentially competent lip.

C. Strap like lower lip-

It is the special type of lower lip which retract excessively during excessively during excessively behaviors in certain indivisual.

Etiology- It is due to defect in tissue morphology.

Behaviors of strap like lower lip.  

i) it may low lip line.

ii) It may high lip line.

iii) It may retracts normally.

iv) It may retracts firmly.

Affected teeth-

Strap like lower lip usually affect the position of anterior teeth.

Effects of strap like lower lip-

 i) Strap like lower lip with competent lips-

 Retro clination of upper teeth.

 ii) Strap like lower lip with incompetent lips-

 Retorclination of lower teeth.

iii)  When the active lower lip line is low and retracts excessively-

 Retroded mandibular alveolar process.

 Protruded chin.

 Retorclination of lower incisors.

iv)  When the lip is low and firmly retracting

 It will be produce class II div-I mal occlusion.

v)  When the lip line is high and firmly reacting type-

 Incase of mild to moderate class-II dental base.

 It may produce class-II div-II malocclusion.

b) In sever class II dental base-

 It may produce class Ii div-II I malocclusion.

Fig: Diagram Showing Class II Division 1 Incisor relationship and unfavourable lower lip

Everted lips- here lips are often full and everted.

Effects of everted lips –

This type of lip morphology is commonly associated with- proclination of both upper and lower labial segment and causes bimaxsillary proclination.

Effect of bimaxillary proclination- 

     Face profile convex.

     Increased over jet.

     Narrowing of both arch.

     Spacing.

CHEEKS
The cheeks have moulding effect on the buccal teeth as the lips have on the anterior teeth. The effects of cheeks are counteracted by the tongue.
Effects of cheeks:

When the tongue thrusts forward during atypical swallowing and provide less support to the buccal teeth. as cheek pressure is not counteracted by this tongue, it causes narrowness of the arch and ultimate results mal occlusion (i.e. cross bite)

Fig: Lip, Cheek & Tongue exert balancing force on the teeth & supporting bony structures.

TONGUE

The size position and behavior is important in determining the shape and position of dental arches.

Effects of tongue:

i) Macroglossia- a large tongue which is positioned forward due to any functional need may causes bi-maxillary   

        proclination of anterior teeth with spacing.

ii) Microglossia- a small tongue backwardly placed gives less pressure then cheeks and lips causes narrowing of arch 

        and ultimately results cross bite.

iii) Tongue which is held very high in the roof of mouth may produce a wider upper arch and a narrow lower arch causing 

        cross bite.

iv) Incompetent lip but habitually apart with large overjet-

 Proclination of upper incisor.

 Incomplete over bite.

v) Active tongue thrusting activity during swallowing and speech-

         It may causes certain abnormalities such as-

a) Proclination of anterior teeth.

b) Grossly reduced over bite.

c) Anterior open bite.

d) Bimaxillary proclination.

e) Posterior open bite incase of lateral tongue thrust.

f) Posterior cross bite

Fig: Diagram showing proclination of upper incisors associated with a forward thrust of tongue.

Type of tongue thrusting–

According to cause tongue thrusting is two type.

i) Adaptive behavior- mild intensity and associated with functional need. 

ii) Endogenous tongue thrusting behavior- strong intensity and in born atypical pattern of neuromuscular activity.

Management of tongue thrust:

a) Factors to be considered-

i) Types of malocclusion.

ii) Degree of malocclusion.

iii) Scope of problem.

iv) Maturity of the child.

v) Attitude and the degree of co-operation.

b) Counseling of the parents and patients.

c) Treatment-

i) Correction of the habit – by tongue guard.

         May be-

a) Removable

b) Fixed.

Anterior

Lateral. 

ii)   Appliance to corrected the proclination.

iii) Appliance to correct the any other malocclusion.

Fig: Correction of habit by tongue guard.

FRAENUM

Before eruption of the teeth, the upper labial frenum is continuous with the incisive papilla and as teeth erupt, its attachment to the alveolar process normally recedes to a points midway between the alveolar border and labial sulcus.

In abnormal condition fraenum is thick, wide and fleshy and passes between the central incisors to run into the incisive papilla.

It causes-

Fig: Median diastema and thick labial fraenum.