Surgical relapse /certified fixed orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

INTRODUCTION
AJO-DO 1991
The advent of orthognathic surgery has given the practicing
orthodontist, in conjunction with the oral surgeon, the ability to
correct skeletal deformities that previously had to be treated by
orthodontic means alone. Often these orthodontic attempts to
camouflage the skeletal deformity were unsatisfactory, since they
required the introduction of severe dental compensations in an
attempt to accommodate to the poor skeletal relationships.
As orthognathic surgery has grown more sophisticated, it has
allowed the surgeon to address many deformities that were
previously untreatable. www.indiandentalacademy.com

However, the long-term stability of changes resulting from
these surgical procedures has been an area of major concern
since the early days of orthognathic surgery, because the final,
long-term result, both esthetic and functional, is directly related to
the degree of postsurgical stability.
Stability is a key goal of both orthodontic treatment and
orthognathic treatment; lack of stability is considered a
complication, particularly as relates to the surgical aspect of the
correction.

REVIEW LITERATURE
PROFFIT AND WHITE (1970),AO,were among the first to
mention relapse after surgical-orthodontic therapy. They felt that
relapse could be avoided by concentrating on eliminating the
original causes contributing to the original malocclusion as much
as possible, and by not operating while patients are still growing.
KENT AND INDOUINA (1970) J. Louisiana Dent. Assoc
state that correction of the openbite deformity is one of the most
challenging problems. Openbite treated with the combined efforts
of surgeon and orthodontist should produce stable results in
certain cases; however, regression is seen because of the
influence of the tongue, enveloping muscles of the jaw, unusual
skeletal features, or bone pathology..

POULTON AND WARE (1971),AJO, stated that, “Probably the
suprahyoid muscles, which have been lengthened, are the main
force contributing to the relapse.”
WICKWIRE ET. AL. (1972),JOS, noted the affect of the
mandibular osteotomy on tongue position. They felt that the
anterior and superior position of he hyoid bone after Class II
surgery of the mandible was viewed as another indication of
muscle tension, stating that “It appeared, then, that stability of the
surgical result would be associated in some way with the stability
of the hyoid position.”

In 1973, MCNEILL, Trans. Eur. Orthod. Soc.,
Suggested three possible mechanisms for regression:
1.Distraction of the condyle from the glenoid fossa at the time of
Surgery.
2.Condylar distraction due to healing scar tissue around the
osteotomy site.
3.Posterior migration of the anterior mandibular segment in
response to tension of the attached muscles and soft tissues
during the fixation period.
STEINHAUSER,JOS, stated that “We think there is less relapse
tendency in the mandibular advancement when combined with
suprahyoid myotomy, but we cannot yet prove this.”

POULTON AND WARE (1973),AJO, showed skeletal changes
during maxillomandibular fixation. They measured relapses of
50% to 80%, but improved their results by the use of a neck brace
and posterior interocclusal bite opening for several months after
surgery.
GUERNSEY(1974),OS, reported a retrospective study of six
cases. He also found relapse in the immediate postoperative
period and while the patients were still in intermaxillary fixation,
and suggested suprahyoid myotomy.
GOLDSPINK(1976),Bristol J. Wright Ltd.
Reported that skeletal muscles will adapt to a physiologic
stretching of 40% of their resting length after four weeks of stable
skeletal immobilization. www.indiandentalacademy.com

WOLFORD ET AL. (1978),OS, noted that the mandibular
advancement is more stable in low-angle cases and less stable in
highangle cases.
EPKER ET AL. (1978),OS, stated in 1978 that – “As a reliable
surgical principle, the greater the magnitude of advancement, the
greater will be the potential for relapse”.
BELL AND JACOBS (1979),AJO, pointed out the need for
possible maxillary surgery in conjunction with mandibular
advancement to allow for autorotation and decrease the tendency
for relapse.

WORMS ET AL. (1980),AO, University of Minnesota, seven
factors that could contribute to regression:
1)Condyle displacement 2)Condyle resorption 3)Gnathological
errors
4)Fibrous union 5)Misdiagnosis 6)Differential treatment planning
7)Proportionality.
EPKER AND WESSBERG (1982),BJO, They conclude that dental
stabilization alone without control of the proximal segment of the
mandible results in the greatest likelihood of skeletal relapse
following surgical advancement. Prolonged skeletal stabilization
with control of the proximal segment of the mandible is suggested
as the only practical method currently available for assuring
maximum stability. www.indiandentalacademy.com

BLOOMQUIST (1983),AAO-AAOMS Clinical Congress.
Suggests a need to improve fixation at the osteotomy site,
advocating a single lag-screw at each osteotomy site to control
changes between the proximal and anterior segments.
PROFFIT, TURVEY, PHILIPS,1989,JOMFS. When maxilla is
moved upward, the postural position of the mandible alters in
concert with the new maxillary movement, and occlusal forces
tend to increase rather than decrease.(This controls any tendency
for maxilla to immediately relapse downward, and contributes to
the excellent stability of this surgical movement)

MOORE AT AL,(1991),JOMFS, They found that the surgical
group with the heighest risk of condylar resorption is women 20-
30 yrs of age with high mandibular plane angles and preoperrative
TMD signs and symptoms.
SNOW AT AL(1991),IJAOOS, Studied post surgical mandibular
growth appeared to occur mainly in the vertical plane.
BAILEY, DUONG, PROFFIT(1998),IJAOOS, Surgical correction
of C-III problem is less stable than C-II correction in the short-term
post-surgically, it appears to be more stable long term.

HARADA, SUMIDA, ENOMOTO, OMURA(2002), EJO, They
suggest that a combination of a Lefort-I and horse shoe
osteotomy is a useful technique reliable superior repositioning of
the maxilla. The post operative change in the maxilla using this
combination osteotomy is comparatively stable.

Theories for relapse:
AJO-DO 1991
(1) stretching of the muscles of mastication and the suprahyoid
musculature,(2) condylar distraction during surgery,(3) upward
and forward rotation of the mandible, and (4) changes in rotational
position between the proximal and distal segments.
Simultaneously, various surgical techniques and postsurgical
therapies have been advocated to minimize relapse:
These are suprahyoid myotomy and cervical collars, which were
used in attempts to reduce muscle tension after surgery.

Numerous fixation techniques to reduce
postsurgical relapse:
(1) upper- and lower-border wiring, (2) Steinmann pins to
stabilize the maxilla, (3) skeletal-wire fixation, and (4) rigid fixation.
Studies that examined independent mandibular advancements
and maxillary LeFort I procedures have indicated a strong
tendency toward reduced amounts of relapse when either
skeletal-wire fixation or rigid fixation is used.

Factors necessary to achieve stability
(vanarsdaal)
Orthodontic considerations:
1) Proper diagnosis of patients who would most benefit from
combined therapy:
*In borderline situations
*In other cases surgery is clearly needed

2) Growth factors and the timing of the referral:
•For moderate and severe C-III mandibular exess pateints
•For mandibular deficiency patients
•Patients with excessive vertical growth ( C-I & C-II )
•For maxillary transverse deficiency patients
•Psycho social needs
•The timing of referral.

4) Dental stability:
5) Pre surgical orthodontic
preparation:
3) TMJ stability:

Surgical considerations:
1) Treatment plan:
surgery in which jaw,
single or double jaw procedures,especially for open bite.
2) Design of osteotomy:
maintenance of blood supply and accomplishment of
objectives.
3) Type of fixation:
*dental skeletal, rigid, semirigid, or combination
*even with rigid osseous fixation, 13 of 50 mandibular
advancement patients had greater than 25% relapse.

4) Muscles of mastication and blood supply:
5) Supra hyoid muscle pull:
6) Type of mandibular rotation:
downward, backward moment is more stable than upward,
forward movement.
7) The stability decrease as the magnitude of surgical correction
increases, especially in the following:
* maxillary vertical deficiencies.
* mandibular horizontal deficiencies.
8) Stability of the condylar position:
9) Neuromuscular adaptation:

Three principles that influence post-surgical
stability:
I) Stability is greatest when soft tissues are relaxed during
the surgery and least when they are stretched:
Moving maxilla up relaxes tissues, moving the mandible
forward stretches tissues, but rotating it upward posteriorly
and downward anteriorly decreases the amount of stretch.
least stable mandibular advancement:- are those that lengthen
the ramus and rotate the chin up.
most stable mandibular advancement:- rotate mandible in
opposite direction.
The least stable orthognathic surgical procedure is widening of
the maxilla that stretches the heavy, inelastic palatal mucosa.

II) Neuromuscular adaptation is essential requirement for
stability:
Fortunately, most orthognathic procedures lead to good
neuromuscular adaptation.
Repositioning of the tongue to maintain airway dimensions,(I.e., a
change in tongue posture) occurs as an adaptation to changes
produced by mandibular osteotomy.
Neuromuscular adaptation does not occur when the
pterygomandibular sling is stretched during mandibular
osteotomy, as when the mandible is rotated to close an openbite.

III) Neuromuscular adaptation affects muscular length, not
muscular orientation:
If the orientation of a muscle group such as the mandibular
elevators is changed, adaptation cannot be expected.
Successful mandibular advancement requires keeping the ramus
in an upright position rather than letting it incline forward as the
mandibular body is brought forward.
The same is true, in reverse, when the mandible is setback: a
major cause of instability appears to be the tendency at surgery to
push the ramus posteriorly when the chin is moved back.

Post surgical stability – clinical success.
PROFFIT (1996) IJAODS
Stability after surgical repositioning of the jaws varies depending
on the direction of movement, the type of fixation used, and the
surgical technique employed, largely in that order of importance.
The various jaw movements possible at surgery were ranked in
order of stability and predictability.

SURGICAL ORTHODONTIC TREATMENT:
A HIERACHY OF STABILITY IJAOOS,1996
MORE Maxilla up VERY STABLE
Mandible forward 90%
Chin any direction STABLE 80%
Maxilla asymmetry
STABLE Mx up + Mn forward STABLE
PREDICTABLE Mx forward + Mn back Rigid fix only
Mandible asymmetry
LESS Mn back
Mx down PROBLEMATIC
Mx wider

The most stable orthognathic procedure is superior
repositioning of the maxilla, closely followed by mandibular
advancement in patients whom anterior facial height is mantained
or increased.
Stability of mandibuar advancement is influnced by the pattern
of rotation of the mandible as it is advanced. Rotating the
mandible so that anterior face height is decreased, the mandibular
angle decreases, the gonial angle tends tobe pulled forward. This
stretches soft tissues in that area, and stability is compromised.
(Then combined surgery is more stable)
Mandibular setback is often unstable, so is downward movement
of the maxilla, that creates downward-backward rotation of the
mandible.
(controlling the inclination of the ramus at surgery is key to
stability) www.indiandentalacademy.com

Prevention of Relapse in Surgical-Orthodontic
Treatment JCO 1986
Factors that affect the stability of combined orthodontic and
surgical treatment vary according to the specific dentofacial
deformity being corrected. However, there are usually four basic
stages of treatment.
There are four basic stages of treatment:
1) Pre-surgical orthodontic phase:-
In this teeth are positioned so that surgery can produce an
occlusion to be finished after surgery.www.indiandentalacademy.com

2) Immediate pre-surgical treatment planning:-
it determines the exact magnitude of surgical correction and of
any adjunctive procedures such as genioplasty, chelioplasty, or
alar cinch.
3) Surgical procedure & intermaxillary fixation:-
4) Post-surgical orthodontic treatment:-

Mandibular Advancement
Presurgical Orthodontic Treatment
• Eliminate dental compensations (make the occlusion more
Class II).

• Properly manage tooth size discrepancies.
• Adequately level both arches.
• Properly manage transverse discrepancies.

• Avoid bimaxillary protrusion.
Immediate Presurgical Treatment Planning
• Take accurate presurgical records.

• Make an accurate cephalometric prediction tracing
• Determine the magnitude of suprahyoid muscle lengthening.

• Construct an occlusal surgical splint when necessary.
Surgery and Intermaxillary Fixation
• Mobilize soft tissues.
• Control condyle-proximal segment positions.

• Prevent relapse during intermaxillary fixation.
• Avoid condylar resorption.
•Postsurgical Orthodontic Treatment

Maxillary Superior Repositioning
• Properly use vertical mechanics.
• Maintain lower arch width.
• Allow adequate space for the indicated surgery.
• Properly relate teeth within the segments.
• Maintain proper arch shape.
• Take accurate presurgical records.
• Make an accurate cephalometric prediction tracing.
• Use accurate definitive model surgery.

• Accurately characterize maxillary anatomy.
• Avoid condylar distraction.
• Avoid poor bone contact.

• Avoid transverse maxillary relapse.
• Avoid interdental relapse.
Postsurgical Orthodontic Treatment
• Take immediate orthodontic control after release of fixation.
• Re-approximate teeth adjacent to osteotomies or ostectomies.
• Use intermaxillary elastics sparingly.

Maxillary Advancement and Inferior Repositioning
Maxillary Advancement
• Eliminate dental compensations (make the occlusion more
Class III).
• Properly manage tooth size discrepancies; adequately level
both arches.

• Mobilize soft tissues.
• Do not use pterygomaxillary junction bone grafts for
stabilization.

Maxillary Inferior Repositioning
• Properly manage lower arch position.
• Properly manage the shape of the upper arch or segments.

• Construct an intraoral skeletal stabilization appliance.
• Evaluate interocclusal space.

• Use appropriate bone-grafting techniques.
• Control infection.

CONCLUSION
“ALTHOUGH THE PROCEDURES PERFORMED
TODAY ARE BASED SCIENTIFICALLY ON A
VARIETY OF WORKING HYPOTHESES, THE RELAPS
PROBLEMS THAT STILL OCCUR ARE REMINDERS
THAT SOME OF THE TREATMENT PROVIDED MAY
HAVE COMPONENTS OF EMPIRICISM”.

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