Functional Orthodontic Examination
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Describe functional examination of face (physiologic examination).
Answer. Functional orthodontic examination studies dynamic nature of stomatognathic system for the optimal functioning.
Functional orthodontic examination identifis the etiology of malocclusion and helps in planning the type of orthodontic treatment which is initiated.
Detailed functional orthodontic examination consists of:
- Examination of postural rest position and maximum intercuspation
- Examination of path of closure
- Examination of TMJ
- Examination of orofacial dysfunctions
Read And Learn More: Orthodontics Question And Answers
Postural Rest Position
- This is the position of mandible at which the muscle which closes the jaws and those which open them are in a state of minimum contraction to maintain the posture of the mandible.
- At postural rest position, a space exist between they maxillary and mandibular jaws which is known as freeway space. Normally it is 3 mm in canine region.
- Various methods are there to assess the postural rest position. At the time of examination patient should be seated upright, with back unsupported and asked to look straight ahead.
- Following are some of the methods which are used to correct the postural rest position:
- Phonetic method: Ask the patient to repeat some of the consonants such as ‘M’ or ‘C’ or repeat the word such as ‘Mississippi’. Mandible return to the postural rest position 1 to 2 seconds aftr the exercise. Ask the patient not to change the jaw, lip or tongue position after phonation, as dentist part the lips to study interocclusal space.
- Command method: Ask the patient to perform certain functions such as swallowing. Mandible tends to return to the rest position following this act.
- Non-command method: Observe the patient as he speaks or swallows. Patient should not be aware that he is examined. This is done by talking about various topics unrelated to the patient while observing him or her.
Methods Employed to Measure Interocclusal Clearance
Following are the method:
- Direct intraoral procedure: Vernier Calipers can be used directly in patient’s mouth in canine or premolar region to measure the freeway space.
- Direct extraoral procedure: Two marks should be placed, one on the nose and another on the chin and mid-sagittal plane. Distance between these two points is measured after instructing the patient to remain at the rest position. Later on ask the patient to occlude the teeth and distance between two points should be measured again. Distance between two readings is known as freeway space.
- Indirect extraoral procedure: Two of the lateral cephalograms at rest position and another in centric occlusion help in establishing the freeway space.
Evaluation of Path of Closure
Path of closure is the movement of mandible from rest position to the habitual occlusion. Abnormalities of the path of closure is seen in some form of the malocclusion.
- Forward path of closure: This occurs in patients with mild skeletal prenormalcy or edge to edge incisor contact. In these patients mandible is guided to more forward position to allow mandibular incisors to go labial to maxillary incisors.
- Backward path of closure: In Class II division 2 cases there is presence of premature incisor contact due to retroclined maxillary incisors. So mandible is guided posteriorly to establish the occlusion.
- Lateral path of closure: Lateral deviation of mandible to right or lef side is associated with occlusal prematurities and narrow maxillary arch.
Examination of TMJ
- Functional examination routinely consists of auscultation and palpation of temporomandibular joint and musculature associated with mandibular opening.
- Examine the patient for symptoms of temporomandibular joint problems such as clicking, crepitus, pain of masticatory muscles, limitation of jaw movement, Hypermobility and the morphological abnormalities.
- Maximum mouth opening should be determined by measuring distance between maxillary and mandibular incisal edges with mouth wide open.
- Normal inter-incisal distance is 40 to 45 mm
Examination of Orofacial Dysfunctions
It consists of analysis of following functions, i.e. swallowing, lips, tongue, speech and respiration.
Examination of Swallowing Pattern
- In newborn tongue is relatively large and protrude between gum pads and take part in establishing the lip seal. This swallowing is known as infantile swallow and is seen till one and a half to two years of age.
- As buccal teeth start erupting infantile swallow is replaced by the mature swallow.
- Persistence of infantile swallow can lead to malocclusion. So the swallowing pattern of the individual should be examined.
- Persistence of infantile swallow is indicated by presence of following features:
- Protrusion of tip of tongue
- Contraction of perioral muscles during swallowing
- No contact at molar region during swallowing.
Examination of Tongue
- Assess posture, size, shape and function of tongue.
- Size of tongue can be microglossia, i.e. small tongue or macroglossia, i.e. dentition is spaced and crenations are seen on lateral border of tongue.
- Tongue thrust is the most common functional aberration of tongue. Anterior tongue thrust is associated with anterior open bite and lateral open bite is seen with lateral tongue thrust. Patient having complex tongue thrust occlude teeth in molar region.
- Posture of tongue can lead to malocclusion. Normal resting position of tongue is retracted tip lying just behind mandibular incisors and lateral border rest on linguo–occlusal surface of mandibular posterior teeth. In class II tip of the tongue is more retruded in rest position while in class 3 tip of the tongue lies forward.
Examination of Lips
- Assessment of lips is done for confiuration, functioning and presence of dysfunctions.
- Lip dysfunctions which occur commonly are lip thrust and lip insuffiency.
- Dysfunctions of lip are observed when patient is speaking or swallowing.
- During swallowing pronounced lip activity is unphysiologic.
Examination of Respiration
- Respiration should be examined to check whether nasal breathing is present or not.
- If there is difficulty in nasal breathing, there is presence of mouth breathing.
- Mouth breathing leads to disturbed orofacial musculature which leads to adenoid facies.
- Various tests for assessing mouth breathing are visual examination, mirror test, buttrfl test and water holding test.
- Mirror test: Held a double sided mirror between nose and mouth. Fogging over the nasal side of the mirror indicates nasal breathing while fogging towards oral side indicates oral breathing.
- Cotton test: Buttrfl shaped piece of cottn is placed over the upper lip below nostrils. If cottn flttrs down, this indicates nasal breathing. This test determines unilateral nasal blockage.
- Water test: Ask the patient to fil his mouth with water and retain it for the period of time nasal breathers accomplish this with ease while mouth breathers feels difficulty.
- Observation: In nasal breathers the external nares get dilated at the time of inspiration. In mouth breathers, there is no change in external nares or they can constrict during inspiration.
Examination of Speech
- Various malocclusions can cause defects in the speech due to interference with movement of tongue and lips. This is observed by undergoing conversation with the patient.
- Ask the patient to read out from a book or ask to count from 1 to 20 while observing the speech.
- Patients having tongue thrusting habit tend to lisp while patients with clef palate may have a nasal tone.
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