Lecture 7 correction of dentofacial deformities Part 2

Mandibular Deficiency
• The most obvious clinical feature of mandibular deficiency is
the retruded position of the chin as viewed from the profile
aspect.
• Other facial features often associated with mandibular
deficiency may include an excess labiomental fold with a
procumbent appearance of the lower lip, abnormal posture of
the upper lip, and poor throat form.
• Intraorally, mandibular deficiency is associated with Class II
molar and canine relationships and an increased overjet in
the incisor area.

• Surgical correction of mandibular deficiency was described as
early as 1909. However, early results with surgical advancement
of the mandible before the 1950s were extremely disappointing.
• In 1957, Robinson described surgical correction of mandibular
deficiency using an extra oral surgical approach, a vertical
osteotomy, and iliac crest bone grafts in the area of the osteotomy
defect.
• Several modifications of this technique were described over
subsequent years. This type of extraoral approach may be useful
in rare circumstances, including severely abnormal bony anatomy
or for revision surgery.
• However, the extraoral incisions have the disadvantages of facial
scarring and potential injury to branches of the facial nerve.

• Currently, the BSSO, described previously for mandibular
setback, is the most popular technique for mandibular
advancement.
• This procedure is readily accomplished through an
intraoral incision.
• The Significant bony overlap produced with the BSSO
allows for adequate bone healing and improved
postoperative stability.
• The osteotomy is frequently stabilized with rigid fixation
plates or screws, eliminating the need for IMF.

Case report of mandibular advancement. A and E, Preoperative facial esthetics
demonstrating clinical features of mandibular deficiency. C and D, Preoperative
occlusion demonstrating Class II relationship and oveljet. E and F, Diagrammatic
representation of bilateral sagittal split osteotomy with advancement of mandible.

G and H, Postoperative facial appearance. I and J, Postoperative
occlusion. K and L, Preoperative and postoperative radiographs

• If the anteroposterior position of the chin is adequate but
a Class II malocclusion exists, a total subapical osteotomy
may be the technique of choice for mandibular
advancement.
• By combining the osteotomy with interpositioned bone
grafts, this technique can be used to increase lower facial
height.

Total subapical osteotomy. Dentoalveolar segment of
mandible is moved anteriorly, allowing correction of Class II
malocclusion without increasing chin prominence.

• When a proper occlusal relationship exists or when anterior
positioning of the mandible would not be sufficient to produce
adequate projection of the chin, an inferior border osteotomy
(Le., genioplasty) with advancement may also be performed.
• This technique is usually performed through an intraoral
incision. The inferior portion of mandible is osteotomized,
moved forward, and stabilized.
• In addition to anterior or posterior repositioning of the chin,
vertical reduction or augmentation and correction of
asymmetries can also be accomplished with inferior border
osteotomies. Alloplastic materials can occasionally be used to
augment chin projection; the material is onlayed in areas of
bone deficiencies.

Inferior border modification (i.e., genioplasty) techniques.
A, Advancement of inferior border of mandible to increase chin projection.
B , Diagram of implant used to augment anterior portion of chin, eliminating
need for osteotomy in this area.
C, Clinical picture demonstrating chin defiCiency.
D, Postoperative photograph after advancement of inferior portion of anterior
mandible.
E, Preoperative radiograph. F, Postoperative radiograph.

Maxillary Excess
• Excessive growth of the maxilla may occur in the anteroposterior, vertical, or
transverse dimensions. Surgical correction of dentofacial deformities with total
maxillary surgery (i.e., Le Fort 1) has only become popular since the early
1970s.
• Before that time, maxillary surgery was performed on a limited basis, and most
techniques repositioned only portions of the maxilla with segmental surgery
During the early years of maxillary surgery, many techniques were performed in
two stages: facial or buccal cuts were performed during one operation; then
sectioning of palatal bone was performed 3 to 4 weeks later.
• This staging was done under the assumption that this was necessary to maintain
adequate vascular supply to the osteotomized segment. As experience and
understanding of these techniques increased, several procedures for anterior
and posterior segmental surgery evolved that used single-stage techniques.

• In the early 1970s, research by Bell et al. demonstrated that total maxillary
surgery could be performed without jeopardizing the vascular supply to the
maxilla. This work showed that the normal blood flow in the bony segments
from larger feeding vessels could be reversed under certain surgical
conditions.
• If a soft tissue pedicle is maintained in the palate and gingival area of the
maxilla, the transosseous and soft tissue collateral circulation and
anastomosing vascular plexuses of the gingiva, palate, and sinus can provide
adequate vascular supply, which allows mobilization of the total maxilla.
• Total maxillary osteotomies are currently the most common procedures
performed for correction of anteroposterior, transverse, and vertical
abnormalities of the maxilla.

• Vertical maxillary excess may result in associated facial
characteristics, including elongation of the lower third of
the face; a narrow nose, particularly in the area of the alar
base; excessive incisive and gingival exposure; and lip
incompetence

Typical clinical features of vertical maxillary excess. A and B, Full-face and profile views
demonstrating elongation of lower third of face, lip incompetence, and excessive gingival
exposure. C and D, Total maxillary osteotomy with superior repositioning combined with
advancement genioplasty. E and F, Postoperative full-face and profile views after total
maxillary osteotomy with superior repositioning and chin advancement.

• These patients may exhibit Class l, Class II , or Class III
dental malocclusions.
• A transverse maxillary deficiency with a posterior cross-
bite relationship, constricted palate, and narrow arch form
is often seen with this deformity.

• Vertical maxillary excess is frequently associated with an anterior
open-bite relationship (i.e. , apertognathia) . This results from
excessive downward growth of the maxilla, causing downward
rotation of the mandible as a result of premature contact of posterior
teeth.
• To correct this problem, the maxilla is repositioned superiorly
(impacted ) , particularly in the posterior area. This allows the
mandible to rotate upward and forward, establishing contact in all
areas of the dentition. In some cases the occlusal plane of the
maxilla is level after orthodontic preparation, and the open bite can
be corrected by repositioning the maxilla in one piece.
• In other cases, a step in the occlusal plane must be leveled to
achieve the desired occlusion. This requires repositioning of the
maxilla in segments.

A, Anterior open bite as a result or vertical maxillary excess with entire
maxillary occlusal plane on one level. B, Presurgical occlusion. C, Surgical
correction with superior repositioning of maxilla in one piece. D, Postoperative
occlusion.

E, Open bite with
maxillary occlusal
plane on two levels.
F, Presurgical
occlusion. G,
Segmental maxillary
repositioning to
close open bite and
place segments on
same plane or
occlusion. H,
Postoperative
occlusion.

• Anteroposterior maxillary excess results in a convex facial profile
usually associated with incisor protrusion and a Class II occlusal
relationship.
• Total maxillary surgery can be completed to correct this problem. In
some cases the entire maxilla can be moved in one piece in a
posterior direction.
• In addition to procedures in which the maxilla is moved in one piece,
the bone can be sectioned into dentoalveolar segments to allow
repositioning in the anteroposterior, superior, or inferior directions or
to allow expanding in the transverse direction.
• The following figure demonstrates a three-piece maxillary
osteotomy performed to correct anteroposterior maxillary excess
combined with vertical deficiency.

Case report of segmental maxillary osteotomy. A and B, Preoperative facial
appearance demonstrates extreme protrusion of anterior maxillary segment and
upper lip, decreased nasolabial angle, and decreased lower face height as a result of
maxillary vertical deficiency. C and D, Preoperative occlusion demonstrates
protrusive maxillary incisors and extraction space remaining after removal of
maxillary premolar teeth bilaterally. E and F, Segmental maxillary osteotomy with
closure of premolar extraction space, retraction of anterior segment of maxilla, and
placement of bone graft in posterior maxillary area.

G and H, Postoperative facial appearance. I and j,
Postoperative occlusion. K and L, Preoperative and
postoperative radiographs.

Maxillary and Midface Deficiency
• Patients with maxillary deficiency commonly appear to have a
retruded upper lip, deficiency of the paranasal and infraorbital
rim areas, inadequate tooth exposure during smile, and a
prominent chin relative to the middle third of the face.
• Maxillary deficiency may occur in the anteroposterior, vertical,
and transverse planes. The patient's clinical appearance
depends on the location and severity of the deformity.
• In addition to the abnormal facial features, a Class III
malocclusion with reverse anterior overjet is frequently seen.

• The primary technique for correction of maxillary
deficiency is the Le Fort I osteotomy.
• This technique can be used for advancement of the
maxilla to correct a Class III malocclusion and associated
facial abnormalities

Case report of Le Fort I
advancement.
A and B, Preoperative
facial esthetics
demonstrating maxillary
deficiency evident by
facial concavity and
paranasal deficiency. C
and D , Preoperative
occlusion demonstrating
Class III relationship.
E and F, Le Fort 1
osteotomy for maxillary
advancement.

G and H, Postoperative
facial appearance. (This
patient also underwent a
simultaneous rhinoplasty
procedure.)
I and j, Postoperative
occlusion.
K and L, Preoperative and

• Depending on the magnitude of advancement, bone
grafting may be required to improve bone healing and
postoperative stability.
• In the case of vertical maxillary deficiency, elongation of
the lower third of the face can be accomplished by bone
grafting the maxilla in an inferior position with the Le Fort I
osteotomy technique.

A and B, Inferior repositioning of
maxilla and interpositional bone
grafting.
C, Preoperative profile view
demonstrating vertical deficiency of
lower third of face and resulting
appearance of relative mandibular
excess.
D, Postoperative view after inferior
repositioning of maxilla.
Note normal facial vertical and
anteroposterior relationships.
E, Preoperative radiograph.
F, Postoperative radiograph. Bone
plates and auxiliary vertical struts are
seen in this view.

• This technique improves overall facial proportion and
normalizes exposure of the incisors during smiling.
• Also, in a large number of patients with Class III
occlusions the jaw blamed by the patients and sometimes
by dental providers is the mandible , when the problem is
actually maxillary deficiency.
• Surgery in the wrong jaw in these cases can leave
problematic facial esthetics, especially in male patients.

• In severe midface deformities with infraorbital rim and
malar eminence deficiency, a Le Fort III or modified Le
Fort III type of osteotomy is necessary.
• These procedures advance the maxilla and the malar
bones and, in some cases, the anterior portion of the
nasal bones.
• This type of treatment is commonly required in patients
with craniofacial deformities such as Apert's or Crouzon's
syndrome.

A, Severe midface
deficiency.
B, Le Fort III
advancement.
C, Modified Le Fort III
advancement.
D, Preoperative
profile view of
patient with Apert's
syndrome.
E, Postoperative
profile view.

Combination Deformities and
Asymmetries
• In many cases the facial deformity involves a combination
of abnormalities in the maxilla and the mandible.
• In these cases, treatment may require a combination of
maxillary and mandibular osteotomies to achieve the best
possible occlusal, functional, and esthetic result.

Case report of maxillary
advancement and mandibular
setback.
A and B, Preoperative
facial esthetics demonstrating
severe maxillary deficiency
combined with mandibular
excess.
C and D , Preoperative
occlusion demonstrating Class
III relationship.
E and F, Le Fort I osteotomy
for maxillary
advancement and bilateral
sagittal osteotomies for
setback of the mandible.

G and H,
Postoperative facial
appearance.
I and J ,
Postoperative
occlusion.
K and L,
Preoperative and
postoperative
radiographs.

Case report of superior maxillary
repositioning and advancement,
mandibular advancement, and
genioplasty
A and B, Preoperative facial esthetics
demonstrating typical appearance of
vertical maxillary excess and
mandibular deficiency, including
excess incisor exposure, lip
incompetence, and lack of chin
projection. C and D, Preoperative
occlusion demonstrating Class II
malocclusion.
E and F, Diagram of Le Fort I
osteotomy with superior
repositioning of maxilla, sagittal
osteotomies of mandible for
advancement, and advancement
genioplasty

G and H , Postoperative
facial appearance.
I and J ,
Postoperative occlusion.
K and L, Preoperative and

• In some cases, surgical treatment may involve a
combination of standard surgical procedures described
before in combination with more complicated osteotomies
accomplished through extraoral approach using bone
grafts harvested from the iliac crest.

Case report of superior maxillary
repositioning, extraoral approach for
mandibular advancement, and
genioplasty.
A and B, Preoperative facial esthetics
demonstrating typical appearance of
vertical maxillary excess and
mandibular deficiency, including
excess incisor exposure, lip
incompetence, and lack of chin
projection.
C and D , Preoperative occlusion
demonstrating class II malocclusion.
E and F, Diagram of Le Fort I osteotomy
with superior repositioning of maxilla,
extraoral osteotomies of mandible with
bone grafts, and advancement
genioplasty.

G and H,
Postoperative facial
appearance.
I and j,
Postoperative
occlusion.
K and L ,
Preoperative and
posloperative
radiographs.

• Treatment of asymmetry in more than two planes of
space frequently requires maxillary surgery, mandibular
surgery, and inferior border osteotomies, as well as
recontouring or augmentation of other areas of the maxilla
and mandible.

Facial asymmetry requiring
maxillary and mandibular
osteotomies, genioplasty, and
inferior border recontouring for
correction.
A, Preoperative facial esthetics.
B, Preoperative occlusion.
C and D, Diagrams of Le Fort I
osteotomy with inferior
repositioning on left side and
superior repositioning on right,
sagittal osteotomies of mandible
with advancement on left side
and superior repositioning on
right, asymmetric genioplasty,
and right inferior border
recontouring.
E, Postoperative facial
appearance.
F, Postoperative occlusion.

G, Preoperative radiograph. H, Postoperative radiograph.

Orthognathic Surgery for Obstructive Sleep
Apnea
• Obstructive sleep apnea is the occurrence of apneic
events (breathing stops) during sleep such that a patient
has cessation of airflow for more than 10 seconds.
• This can be a serious condition with manifestations
ranging from sleep disruption deprivation and daytime
somnolence to severe hypoxia during sleep and the
potential of associated respiratory and cardiac
abnormalities, and even death.

• The primary problem is a collapse of the airway during
sleep. This can be a result of decreased muscle tone in
the palate, tongue, or pharyngeal musculature. This
condition can be associated with mandibular deficiency
and the subsequent lack of forward suspension of the
tongue and hypopharyngeal musculature.
• This is usually accentuated in the supine position. Other
factors such as obesity and alcohol or sedative drug use
during sleep can aggravate the problem.

Narrow or
collapsed
airway as a
result of
mandibular
deficiency.

• The complete workup for the patient with obstructive
sleep apnea is beyond the scope of this chapter but
usually includes a comprehensive physical evaluation,
nasopharyngoscopy, a dentofacial evaluation, and
polysomnography sleep study.
• Treatment may included nonsurgical measures such as
weight loss, positional changes during sleep, jaw
positioning devices, or continuous positive airway
pressure using a facial or nasal mask during sleep.

• Surgical correction may include a limited uvulopalatoplasty or
uvulopharyngealpalatoplasty in which varying portions of the soft
palate, uvula, tonsils, and pharyngeal walls are resected to open
the airway. Maxillary and mandibular advancement with
orthognathic surgery has also been shown to be effective in
improving the airway in many patients
• This improvement is a result of expanding the airway at the level
of the soft palate, base of the tongue, and hypopharyngeal airway.
This can be seen by comparing preoperative and postoperative
radiographs. The airway expansion resulting from surgery actually
includes all dimensions, even lateral expansion.

B, Preoperative cephalometric radiograph showing narrow hypopharyngeal
airway.
C, Postoperative cephalogram showing significant expansion of the airway.

F
D, Three-dimensional view of
the airway can be obtained
from computed tomography
data. The skeletal components
are subtracted and the airway
enhanced (in red) using
computer technology.
E, Enhanced view of airway
showing small airway volume
and area of maximum
constriction.
F, Postoperative view showing
an increase in airway after
maxillary and mandibular
advancement.

DISTRACTION OSTEOGENESIS
• One new approach to correction of deficiencies in the mandible and the
maxilla involves the use of distraction osteogenesis (DO).
• When correcting deformities associated with these deficiencies, the
conventional osteotomy techniques have several potential limitations.
When large skeletal movements are required, the associated soft tissue
often cannot adapt to the acute changes and stretching that result from
the surgical repositioning of bone segments.
• This failure of tissue adaptation results in several problems, including
surgical relapse, potential excessive loading of the TMJ structures, and
increased severity of neurosensory loss as a result of stretching of nerves.
In some cases, the amount of movement is so large that the gaps created
require bone grafts harvested from secondary surgical sites such as the
iliac crest.

• DO involves cutting an osteotomy to separate segments of
bone and the application of an appliance that will facilitate the
gradual and incremental separation of bone segments.
• The gradual tension placed on the distracting bone interface
produces continuous bone formation.
• Additionally, surrounding tissue appears to adapt to this
gradual tension, producing adaptive changes in all
surrounding tissues, including muscles and tendons, nerves,
cartilage, blood vessels, and skin.
• Because the adaptation involves a variety of tissue types in
addition to bone, this concept should also include the term
distraction histogenesis.

Distractor appliance used for mandibular advancement.
A, Osteotomy of posterior mandibular body and ramus area with
distractor in place.
B, View showing distraction appliance fully expanded. Regenerate
bone fills the intrabone gap during slow incremental activation of
distractor that slowly separates the segments.

• The concept of distraction is not new. The use of traction
techniques to help bones heal to a correct length can be
traced back to the time of Hippocrates when an external
device was used to apply traction to a fractured and
shortened leg.
• A Russian surgeon, Gavril Ilizarov, developed the current
concept of correcting bone deficiencies in the 1950s. The
result of his work was not widely disseminated to the rest of
the world until the late 1970s and early 1980s.
• Since that time, the application of these principles has
extended to all forms of orthopedic correction, including
craniofacial surgery.

• DO involves several phases, including the osteotomy or
surgical phase, the latency period, the distraction
phase, the consolidation phase, appliance removal, and
remodeling.
• During the surgical phase, an osteotomy is completed,
and the distraction appliance is secured. In the latency
phase, very early stages of bone healing begin to take
place at the osteotomy–bone interface. The latency phase
lasts generally 7 days, during which time the appliance is
not activated.

• After the latency period, the distraction phase begins at a rate of 1
mm per day. This distraction rate is usually applied by opening or
activating the appliance 0.5 mm twice each day.
• The amount of activation per day is termed rate of distraction; the
timing of appliance activation each day is termed rhythm. During
the distraction phase, the new immature bone that forms is called
regenerate bone. Once the appropriate amount of distraction has
been achieved, the appliance remains in place during the
consolidation phase, allowing for mineralization of the regenerate
bone. The appliance is then removed, and the period from the
application of normal functional loads to the complete maturation
of the bone is termed the remodeling period.

• Because the use of these techniques in orthognathic surgery is
relatively new, few long-term studies are available that document all of
the potential benefits of DO.
• Possible advantages include the ability to produce larger skeletal
movements, elimination of the need for bone grafts and the associated
secondary surgical site, better long term stability, less trauma to the
TMJ, and decreased neurosensory loss.
• DO also has certain disadvantages: The placement and positioning of
the appliance to produce the desired vector of bone movement is
technique sensitive and sometimes results in less than ideal occlusal
positioning, resulting in discrepancies such as small open bites or
asymmetries. Other disadvantages include the need for two
procedures: (1) placement and (2) removal of the distractors. It also
involves increased cost and longer treatment time, with more frequent
appointments with the surgeon and the orthodontist.

• One of the earliest uses of the DO concept in orthognathic surgery involved
widening of the maxilla with a technique termed surgical-assisted rapid
palatal expansion. An adult maxilla with significant transverse deficiency is
nearly impossible to correct with conventional orthodontic treatment. Even
correction with segmental maxillary surgery to produce expansion has often
shown disappointing results. The use of surgical-assisted palatal expansion,
incorporating the concepts of DO, seems to produce better long-term results
in these cases.
• In these cases, the expansion device is secured in place by the orthodontist.
A surgical procedure is then completed by performing the bone cuts as
described for a Le Fort I osteotomy, with the exception that the most posterior
attachment of the lateral nasal wall and perpendicular plate of the palatine
bone are not divided. A midline cut is also completed to create separation
between the central incisors extending along the midpalatal suture. After a
latency period the expansion device is activated 1 mm per day until the
desired expansion takes place.

Distraction osteogenesis with surgically assisted palatal expansion for correction of transverse
maxillary deficiency.
A, Severe constriction of maxilla with inadequate arch length. (Note that severe crowding exists even
though premolars have been extracted.)
B, Expansion device in place.
C, Maxilla expanded (note space between central incisors). Osteogenesis, with bone formation, and
histogenesis, with formation of gingival tissue, are occurring.
D, Space closed with anterior teeth orthodontically aligned using newly formed regenerate bone.
E, Radiograph showing expansion with immature regenerate bone in anterior space.
F, Radiograph after orthodontic alignment.

• During this time, a space develops between the
central incisors, along the midpalatal suture, and at
the area of the osteotomy along the lateral
maxillary wall.
• The regenerate bone gradually fills and matures in
these areas. The appliance is then removed, and
active orthodontic treatment is begun to close the
spaces between teeth, properly align the arch, and
maintain the expansion.

• In the case of mandibular deficiency, the initial surgical
procedure involves performing an osteotomy and
placement of the distraction appliance.
• After a latency period of 7 days, the distraction occurs
with a rate and rhythm of 1 mm per day (completed by
activating the appliance 0.5 mm twice each day).
• Once this distraction is complete, the appliance is left in
place for the consolidation phase, which is usually 2 or 3
times the amount of time required for the distraction
phase. The appliance is then removed, and active
orthodontic treatment continues.

Case report of distraction osteogenesis to correct severe mandibular deficiency. A and B,
Preoperative facial esthetics demonstrating severe mandibular deficiency. C and D,
Preoperative occlusion demonstrating Class II relationship. E, Preoperative
cephalometric radiograph. F, Surgical procedure to create osteotomy and place
distraction appliance.

G, Postoperative radiograph after latency phase complete and
distraction started (chin advancement was completed at the same
time distractors were applied). H, Radiograph after 16 days of
distraction at 1 mm per day. I, Radiograph after distraction appliances
removed, completion of orthodontic treatment, and debanding.

J and K,
Postoperative
facial
appearance.
L and M,
Postoperative
occlusal views.

• Distraction appliances are also available for maxillary and midface
advancement. In some cases of traditional maxillary repositioning,
autogenous bone may be required for grafting into the bone defect.
• The need for grafting obviously requires donor site surgery with the
associated morbidities. DO eliminates the need for graft harvest in many
of these patients. In patients with a cleft lip and palate, substantial
scarring often occurs from multiple previous surgical procedures.
• This scarring combined with significant growth abnormalities creates soft
tissue limitations that may prevent single-stage correction with
conventional orthognathic surgical techniques. DO can be effective in
treatment of these patients by gradually stretching the soft tissue
envelope, generating new soft and hard tissue, eliminating the need for
graft harvest, and providing satisfactory long-term stability.
• The following figure demonstrates the effective use of DO for maxillary
advancement in such patients. Maxillary repositioning with DO may allow
larger advancements with improved long-term stability.

Distraction osteogenesis for
correction of maxillary deficiency.
A, Severe midface deficiency
resulting from cleft lip and palate
and multiple surgical
interventions.
B, Radiograph demonstrating
maxillary hypoplasia and Class III
malocclusion.
C, Radiograph showing
advancement of the maxilla using
distractors.
D, Final profile demonstrating
improved facial balance and
occlusion.

PERIOPERATIVE CARE OF THE
ORTHOGNATHIC SURGICAL PATIENT
• Patients undergoing orthognathic surgery are usually admitted to the
hospital on the day of surgery. Before surgery, medical history taking,
complete physical examination, preoperative laboratory tests, radiographic
examinations, and consultation with the anesthesiologist are completed.
• Orthognathic surgery is accomplished in the operating room, with the
patient under general anesthesia. After surgery, the patient is taken to the
post anesthesia care unit (i.e., recovery room) for an appropriate period,
usually until alert, oriented, comfortable, and exhibiting stable vital signs;
then the patient is returned to the hospital room.
• The nursing staff trained and experienced in the postoperative care of
surgery patients continually monitor postoperative progress. The patient is
discharged when he or she is feeling comfortable, urinating without
assistance, taking food and fluid orally without difficulty, and ambulating
well.

• The postsurgical hospital stay usually ranges from
1 to 4 days. Patients generally require only mild to
moderate pain medication during this time and
often require no analgesics after discharge.
• As soon as is feasible, postoperative radiographs
are obtained to ensure that the predicted bone
changes have taken place and that stabilization
devices are in the proper position.

• The importance of postoperative nutrition should be
discussed with patients and their families before the
hospital admission for surgery.
• During the postoperative hospital stay, a member of the
dietary staff may instruct the patient in methods of
obtaining adequate nutrition during the period of IMF or
limited jaw function.
• Special cookbooks designed for patients undergoing jaw
surgery contain instructions for the preparation of diets in
a blender.

• In the past, one of the major considerations in the
immediate postoperative period was the difficulty
resulting from IMF.
• When the jaws are wired together, the patient has
initial difficulties in obtaining adequate nutrition,
performing necessary oral hygiene, and
communicating verbally. The average IMF period
ranges from 6 to 8 weeks

• In the past few years, several systems using small bone
screws and bone plates have been developed to provide
direct bone stabilization in the area of the osteotomies.
• The most recent development in rigid internal fixation is the
use of screws and plates made of resorbable material. The
materials are capable of maintaining adequate strength to
stabilize bone during the healing period and are then
resorbed by hydrolyzation.
• The use of these rigid fixation systems allows for early
release from or total elimination of IMF, which results in
improved patient comfort, convenience of speech and oral
hygiene, and improved postsurgical jaw stability and function.

A, Use of small bone
plates for stabilization of
maxillary osteotomy.
B, Maxillary
advancement and
downgraft with iliac
crest bone graft
stabilized with bone
plates.
C, Lag screws used to
secure mandibular
sagittal split osteotomy.
D, Bone plates used to
stabilize sagittal split
osteotomy.

• At the time of surgery, a small acrylic occlusal wafer is usually
used to help position and stabilize the occlusion. When the
IMF is released (usually in the operating room), the splint, if
left in place, is wired to the upper or lower jaw. Light elastics
are then placed on the surgical wires, and the combination of
the splint and elastics serves to guide the jaw into the new
postsurgical occlusion.
• When an ideal occlusion can be achieved at the time of
surgery, the use of a splint may be eliminated. After an
adequate accommodation period, the occlusal splint is
removed and the patient is returned to the orthodontist’s care.

A, Interocclusal splint wired to maxilla. Light elastics are
used to help guide the patient into the new postoperative
occlusion. B, Patient 7 days after maxillary osteotomy.

POSTSURGICAL TREATMENT PHASE
Completion of Orthodontics
• When a satisfactory range of jaw motion and stability of the osteotomy
sites are achieved, the orthodontic treatment can be ended. The heavy
surgical arch wires are removed and replaced with light orthodontic wire.
Final alignment and positioning of teeth is accomplished, as is closure of
any residual extraction space.
• The light vertical elastics are left in place at this time to over-ride
proprioceptive impulses from teeth, which otherwise would cause the
patient to seek a new position of maximal intercuspation. The settling
process proceeds rapidly and rarely takes longer than 6 to 10 months.
• Retention after surgical orthodontics is no different from that for other
adult patients, and definitive periodontal and prosthetic treatment can be
initiated immediately after the final occlusal relationships have been
established.

Postsurgical Restorative and Prosthetic
Considerations
• When patients require complex final restorative treatment, it is
important to establish stable, full-arch contact as soon after
orthodontic debanding as possible. Posterior vertical contacts are
important in patients who have only anterior components of
occlusion remaining.
• Well-fitting, temporary, removable partial dentures may suffice, and
these appliances should be relined with tissue conditioning
materials, as needed, to maintain the posterior support during
healing.
• When postsurgical orthodontics is complete, the remainder of
restorative treatment can be accomplished in the same manner as
for any nonsurgical patient.

Postsurgical Dental and Periodontal
Considerations
• The patient should be seen for a maintenance dental and periodontal evaluation
approximately 10 to 14 weeks postoperatively. The mucogingival status is re-
evaluated, the teeth deplaqued, and areas of inflammation or pocketing lightly
scaled. Frequent recall maintenance should continue during the remainder of
orthodontic care, when necessary.
• After the orthodontic appliances are removed, a thorough prophylaxis with a review
of oral hygiene techniques is advisable. A thorough periodontal re-evaluation 3 to 6
months after completion of the postsurgical orthodontics will determine future
treatment needs. Periodontal surgery, including crown-lengthening or regenerative
procedures, should be performed after the inflammation associated with orthodontic
appliances has resolved.
• Areas of hyperplastic tissue should be observed for 3 to 6 months after orthodontic
therapy, unless esthetic or restorative considerations necessitate earlier tissue
removal. After completion of periodontal treatment, recall intervals should be
adjusted to accommodate the individual patient’s needs.

Lecture 7 correction of dentofacial deformities Part 2

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Lecture 7 correction of dentofacial deformities Part 2