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Dr. Mohammed Alruby
Orthodontic treatment
And
airway
Prepared by:
Dr. Mohammed Alruby

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Dr. Mohammed Alruby
Influence of orthodontic treatment on air way
1- Extraction treatment:
- Since 1911 paper written by (calium S case) which start debate about extraction treatment
and its effect on soft tissue profile and mandibular angel.
- The extraction could potentially have an effect on tongue position and may cause alteration
in the upper air way anatomy (UA anatomy) especially the oropharynx.
- Tongue position is considered to be an important factor for UA since the root and posterior
part of tongue from the anterior wall of oropharynx.
- Mesial movement of molars in the extraction space seems to enlarge the space behind the
tongue which improve U A dimension.
- Some authors believed that after incisors retraction there is some movement in the hyoid
bone in posterior and inferior direction which lead to U A reduction.
2- Rapid maxillary expansion: RME:
= RME is splitting of mid palatal suture and expansion of maxillary arch by application of
reciprocal orthopedic force to the teeth and alveolar process on both sides of the arch.
= RME not only separates the mid palatal suture but also effects the circum zygomatic and
circum maxillary sutural system.
= the force level may reach 500 –750 gm/side. The patient instructs to turn the jackscrew
once/day for 7—10 days, after palate has been widened, a new bone is deposited in the area of
expansion, so that, the integrity of the suture is reestablished with 3—6 months.
= the optimal age for expansion is between 5 and 12 years however some clinician reported
palatal splitting and older age, but the results are neither predictable nor stable.
Indication:
1- Unilateral or bilateral buccal cross bite with skeletal background.
2- Cleft lip and palate patient with collapsed maxilla.
3- Anterior posterior as in case of Class III maxillary deficiency.
Contraindication:
1- Uncooperative patients.
2- Patient with anterior open bite, steep mandibular plane and convex profile.
If RME is done it should be associated with extra-oral intrusive mechanics to counterpart the
bite opening effect of RME.
Anatomical effect of RME on nasal cavity:
1- Increase the width of nasal cavity particularly at the floor of the nose adjacent to the mid
palatal suture.
2- The outer wall of the nasal cavity moves laterally.
3- The average increase in the width of the nasal cavity is about 1.9mm, but can wider as much
as 8—10mm at the level of inferior turbinate, while the more superior area might move
medially.
4- The total effect is increase in the intra nasal capacity.
5- The effect of RME on the nasal cavity are progressively decrease toward the back of the
nasal cavity.

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Dr. Mohammed Alruby
6- As the result of lowering the palatal vault, straightening of the deviated nasal septum may
enhanced, which in turn move the septum away from the turbinate bone, thus permit
increase the air volume.
7- Increase in the alar base width and widening the external naris.
Effect of RME on the nasal airway resistance
Some authors studied the effect of RME on nasal airway resistance in patients with constricted
maxilla and difficulty in nasal respiration and concluded the followings:
1- The stenosis caused by obstruction in the more anterior and inferior areas of the nose could
be possibly relived by RME while, the stenosis caused by obstruction in the more superior
and posterior areas would has a little chance to benefit from RME.
2- RME is recommended in patients with bilateral maxillary constriction associated with
difficulties in nasal respiration to gain the maximum benefit in the form of buccal expansion
together with possible relief of nasal stenosis.
3- The opening of mid palatal suture for only increase the nasal capacities in patient with
normal maxillary width cannot be justified, unless the obstruction is shown to be located in
the lower anterior part of the nasal cavity accompanied by a lateral maxillary arch width
deficiency.
In contrast, Subtenly recommended RME in the absence of posterior cross bite in an attempt to
facilitate nasal respiration and enhance the subsequent dento facial development, he stated that,
the development buccal bite will be improved by relapse of the expanded maxillary arch.
** Hershey et al, studied the effect of RME on nasal airway resistance in 17 subject suffering from
constricted maxillary arch and mouth breathing, they concluded the following;
1- RME produce significant reduction in the nasal airway resistance.
2- Low correlation was found between the amount of maxillary expansion and amount of
increase in the nasal width.
3- Low correlation was found between the amount of reduction in the nasal resistance.
4- Low correlation was found between the amount of reduction in nasal resistance and the
point at which the patient will switch from mouth to nasal breathing. This means that, in
some patient, the nasal resistance is markedly reduced, while the patient still habitually
breath through mouth.
5- Nasal resistance was not improved in patient having stenosis posterior to the area affected
by RME as adenoid.
6- When indicated, the RME is not only an effective method for increasing the width of narrow
maxillary arch, but also reduce the nasal resistance to a level compatible with normal nasal
respiration.
== These finding are further supported by the study of Timmos who concluded that, the
extent to which RME will change the mode of respiration in complex owing to the wide
variations in both the nasal airway resistance and the point at which the patient will switch
from oral to nasal breathing, some patients do change their mode of respiration while others
may remain habitual mouth breathers.
== Bishara and Stanly reviewed this subject, they concluded that, the effect of RME on
nasal airway will to a great extent depend upon the cause, location and severity of nasal
obstruction, hence: the effect can vary from no appreciable changes to a marked decrease
in nasal airway resistance.

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Dr. Mohammed Alruby
RME and head posture
== the head posture is entirely related to the respiratory pattern if there is any altering in
the respiratory pattern, such as breathing through the mouth rather than through the nose,
could change the posture of head, jaw, and tongue.
== thus in turn could alter the equilibrium pressure of the jaws and teeth and affect both
jaws growth and tooth position.
== in order to breathe through the mouth, it is necessary to lower the mandible and tongue
and head extended tip back may be lead to the following:
1- Increase face height
2- Super eruption of posterior teeth------- anterior open bite
3- Increased over jet
4- Unusual vertical growth of ramus
5- Downward and backward of mandible
6- Narrowing maxillary dental arch
** Vig et al investigate the effect of total nostril obstruction for 2 hours on head posture, they found
immediate changes in the head posture which become extended about 5 degrees (craniofacial
cervical angel) and after obstruction is relief the head posture returns to original position.
** Hellsing et al studied short term effect induced oral respiration for 30 minutes on head posture,
they found an immediate significant extension of the head by 24 degrees which maintained during
the whole period of oral respiration, and after nasal obstruction is removed the head return to an
average norm.
** Ronning and Huggar: examined the effect of cold air in head posture, they found an extension
of head posture after 30 minutes of exposure of cold air, due to increased nasal airway resistance
that cause change the mode of respiration from nasal to oral.
NB: RME may be able to help solve the nasal resistance to air follow if problem originate from the
anterior nasal cavity.
3-Functional orthopedic appliances:
= the functional appliances that advance the mandible could have positive impact over the
upper airway and increase in the oropharyngeal airway dimension
= Haggi 2008 showing improved oropharyngeal airway by about 25mm by using activator
headgear.
= Iwaski and colleagues 2014 used fixed functional appliance (Herbest appliance) to
enlarge the oropharyngeal airway.
= some studies suggest the using of facemask or headgear has no significant effect on
airway, but other suggest that headgear restrict the forward growth of maxilla with negative
influence on airway.
4- Ortho-gnathic surgery:
= some literature suggests that when mandibular set back osteotomy is performed, the hyoid
bone tends to move posterior and inferior position ------- the tongue carried in more
posterior position, so there is a narrowing in width and depth of airway has been reported
and 1 year after follow up the narrowing of airway still present.
= after maxillary advancement showing an increase in airway
= after mandibular advancement showing an increase in the airway
= maxillo-mandibular advancement more useful in U A and improve the efficacy

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Dr. Mohammed Alruby
= in some anomalies that lead to reduce size of mandible or maxilla may affect the position
og tongue which lead to UA obstruction
= distraction osteogenesis has become accepted method of treatment for patient with hypo
plastic mandible and severely retruded maxilla to increase the airway dimension.
= small size of the mandible and its retruded position causes a corresponding retro-
displacement of the tongue which lead to reduction in airway so mandibular distraction
create change in position of tongue and it is believed to increase the airway.
Thanks