Surgical orthodontics. /certified fixed orthodontic courses by Indian dental academy

Tuesday, March 4, 2014

www.indiandentalacademy.com


ENT OF
TM
DEPAR
ONTICS
ORTHOD
AND
FACIAL
DENTO
PEDICS



Dr. Syed Zameer

HISTORY AND BACKGROUND
PSYCHOLOGICAL IMPLICATIONS
PATIENT SELECTION
ETIOLOGIC FACTORS
ENVELOPE OF DISCREPANCY
DIAGNOSIS
VARIOUS SURGICAL OPTIONS
BIOMECHANICAL FACTORS



INTRODUCTION

The concept of beauty is central to all human cultures regardless of
race ,age and sex and it is deeply rooted in the nature of man .

In various ways ,human esthetics has been woven into the tradition of
human civilization. Physical appearance has always played a
significant role in the development of self-conceptualization and self
esteem, in the establishment of inter personal relationship, in
employment opportunities and in quality of life.


What is orthodontic surgery ?



A procedure by which dento-facial deformities and malocclusions are
corrected with orthodontics combined with the surgical modification of
the facial morphology and various soft tissue structures .

The term orthognathic originates from the Greek words
“Orthos”, meaning straight, and” Gnathos”, meaning jaw.



HISTORICAL BACKGROUND
First mandibular osteotomy : HULLIHEN (1849)
done to correct a protrusive malposition of a mandibular
alveolar segment caused by a burn

Mandibular body osteotomy: VILRAY BLAIR (1897)
done to correct mandibular prognathism (St. Louis Operation)

The beginning of the early orthognathic surgery was in
St.Louis where the orthodontist Edward Angle and the
surgeon Blair worked together.



The area of the body which maximally determines physical
attractiveness is the face. It is a primary means of identification ,
expression and non-verbal communication.
There is a high value of cosmetic characteristics in the current
society and severe cranio-facial deformity may cause significant
psychosocial problems.
Facial deformity is defined as “ a physiognomic form that is
sufficiently negatively marked so as to set the individual apart
from the general population”.
A dentofacial anomaly may have an adverse effect on an individuals self
esteem and self confidence as well as evoke an undesirable social
response .


Concept of “Body image” ( Schilder and Schonfeld )
2 components of body image are
1. Body sense
2. Body concept
Body sense
The actual appearance the person sees when viewing himself in a
mirror or photograph.
Body concept
The internal process of how the patient feels about his appearance.

Generally those patients with a good body image in spite
of having a deformity are better candidates for surgery



EXTERNAL & INTERNAL MOTIVATION

Edgerton & knorr pointed out the importance of external
versus internal motivation.
‘Internal pressure’ would be that originating within the
patient and usually involves depression and a sense of
inadequacy.
‘External pressure’ would include the need to please others
and a desire to overcome career or social problems through
a change in appearance


PATIENT SELECTION
An orthodontist must determine at an early stage why the patient is
seeking treatment and what the patient hopes to achieve .The
surgeon must then decide whether this demand can be met
surgically.
LAVEL emphasized that satisfaction begins with selection of
appropriate patients. The selection can be represented by the
acronym SAFE.

S- Self assessment of attractiveness
A- Anxiety
F- Fear
E- Expectation


ETIOLOGIC FACTORS

Dentofacial deformity

Developmental problem.

Occasionally the deformity is due to a single specific cause,
much more frequently they result from a complex interaction
among multiple factors that influence growth and development.

ETIOLOGY

KNOWN SPECIFIC
CAUSE


HEREDITARY
FACTORS


ENVIRONMENTAL
INFLUENCES

SPECIFIC CAUSES
FACIAL SYNDROMES AND
CONGENITAL
DEFECTS, WHOSE ETIOLOGY
IS PRE-NATAL
FAS AND RELATED PROBLEMS
ANORMALITIES OF NEURAL REST CELL
ORIGIN AND MIGRATION :

Hemifacial microsomia
Mandibulofacial dysostosis
FACIAL CLEFTING SYNDROME
ACHONDROPLASIA
PREMATURE FUSION OF CRANIAL AND
FACIAL SUTURES:

POST NATAL GROWTH
DISTURBANCES OF
KNOWN ORIGIN, INCLUDING THE
EFFECT OF TRAUMA
TRAUMA:

Maxillary trauma
Mandibular trauma(functional ankylosis)
MUSCLE DISTURBENCES(TORTICOLLIS)
CONDYLAR HYPERPLASIA

Plagiocephaly
Crouzon’s syndrome
Apert’s syndrome


HEREDITARY FACTORS
Malocclusion is much more common now than it was in primitive
human populations. It seems logical that one effect of increased
intermarriage among previously isolated population subgroups
would be an increased number of individuals requiring orthodontic
–surgical treatment.
The influence of inherited tendencies seems to be particularly
strong for mandibular prognathism.
CRANIOFACIAL anomalies often have a genetic
background.Reccnt advances in molecular genetics have
revealed a genetic explanation for conditions that do not even
appear to be genetic in origin .


Craniosynostosis ……………………..….. MSX-2
Tricho-dento-osseous syndrome…………..DLX-3 and DLX-7
Cleidocranial dysplasia………………..…..CDFA1
Treacher Collins syndrome ……………....Long arm of ch. 5
Holoprosencephaly…………………….….HPE3
Cleft lip and palate ………………….……MSX1 and TGFB3
Crouzon syndrome………………….…….FGFR2



ENVIRONMENTAL INFLUENCES
Environmental influences on dento facial development includes
obvious external influences such as trauma ,but more importantly , this
category includes the group of etiologic factors related to function.

The importance of posture in controlling soft-tissue pressure
Form

Function

The form function interaction includes both the effects of active
movement and the subtle but long lasting effect of the soft tissue on
the developing skeletal and dental structures.


Tongue habits ,particularly tongue thrust swallowing ,have
been blamed for many instances of protrusion of incisors and
anterior open bite .
Soft tissues of the lips , cheeks and the tongue exert pressure
against the teeth and alveolar process while the tissues are at rest
as well as when they are moving in function.
Although these resting pressures are small in the range of 5 to
15 grams , they are large enough to cause tooth movement and
remodeling of the alveolar process.
BITING FORCE AND JAW MORPHOLOGY
One characteristic of patients with the long-face condition is that
the posterior teeth erupt further than normal. Conversly ,in short
face patients , the teeth are infra-erupted.


It seems obvious that biting force , which opposes eruption ,
should be involved in its control.

It is possible that difference in biting strength and therefore in biting force
,is involved in the etiology of long- and short-face problems.
The relationship between facial morphology and occlusal forces
does not prove a cause and effect relationship.

There are three possibilities
Muscle weakness and thus low occlusal force
may allow the teeth to erupt too much and cause
the mandible to rotate down and back
Excessive eruption of teeth may cause the mandible to rotate down
and back, putting muscles at a mechanical disadvantage that
reduces occlusal force .
The long face pattern and the decrease in occlusal force are both
caused by something else and are not necessarily related.



Respiratory influence
Mouth breathing has been blamed for altered dentofacial development
Harvold etal showed that total blocking the
nares led to Various moderate to severe malocclusions .
(AJODO, 79. 1981).Because the lower jaw was positioned
forward , the deformity always included a component of
mandibular prognathism along with various
displacements of teeth
Total nasal obstruction
Downward backward rotation
Long face deformity


Envelope of discrepancy
There are limits to how far a tooth can be moved, and these limits
become important when bite relationships must be changed to
correct crossbite ,deepbite , open bite or incisor protrusion.



DIAGNOSIS
………the search for truth



Facial proportions and esthetics

A precise and detailed soft tissue evaluation is always
essential to derive proper diagnosis and accurate treatment
plan which maximizes the patient’s benefit.

The most important point in proper analysis of facial esthetics is the
use of a clinical format. Examination should not be based on static
laboratory x-ray film and photographic representation of the patient
alone.



Three important parameters which are to be checked
before proceeding with clinical examination are:-

Natural head position
Centric relation
Relaxed lip posture



Once after these 3 things are established one can go ahead with facial
examination.
Two views of the patient are used for identification of problems in 3
planes of space.
Frontal view
Profile view
Frontal view

1. Outline form & symmetry
2. Facial level
3. Midline alignments
4. Facial one thirds
5. Lower one-third evaluation
6. Upper & lower lip lengths

1. Soft tissue profile angle
2. Nasolabial angle
3. Maxillary sulcus contour
4. Mandibular sulcus contour
5. Orbital rim
6. Cheekbone contour
7. Nasal base-lip contour
7. Upper tooth to lip relationship
8. Nasal projection
9. Throat length and contour
8. Interlabial gap
www.indiandentalacademy.com Subnasale-pogonion line ( sn-pg’)
10.

Outline form & symmetry

General outline form & symmetry are noted. The widest dimension of the
face is the zygomatic width .According to the normal values established by
Farkas with Anthropometric studies the bigonial width is approximately
30% less than the bizygomatic dimension

Short, square facial outlines are indicative of deep bite class II
malocclusion, vertical maxillary deficiency, and in some cases
masseteric hyperplasia.
Long, narrow faces are associated with vertical maxillary excess, or
mandibular protrusion with dental interferences leading to open bite.


Facial level
To examine facial levels a reliable horizontal
landmark is necessary. With the patient in natural head posture,
the pupils are assessed for level with the horizon. If pupils are
level, they are used as the horizontal reference line and adjacent
structures are measured relative to this line. Structures compared
with the pupil line are:-

Upper canine level
Lower canine level
Chin & jaw level



Midline alignments

Midlines are assessed with upper most condyle position and first
tooth contact. If occlusal slides alter joint position, no reliable
midline assessment can be made. The relative positions of soft
tissue landmarks (nasal bridge, nasal tip, philtrum, and chin point)
and dental midline landmarks (upper incisor midline, lower incisor
midline) are noted.
Needed changes are incorporated into the surgical-orthodontic
treatment plan to position these structures on the vertical midline of
the face.

Philtrum is usually a reliable midline structure and can be used as
the basis for midline assessment most often.


Transverse Facial Proportions:

Rule of fifths


Facial one thirds

The Central Fifth:
-

Delineated by the inner canthus of
the eyes
Inner canthal distance= alar base
of nose

The Medial Fifth:
-

Width of mouth= interpupillary
distance
Line from the outer canthus
should coincide with the gonial
angles



Lower one-third evaluation
This area of facial analysis is extremely important in surgical
orthodontic diagnosis and treatment planning. The importance
of relaxed lip position for these measurements cannot be
overemphasized.

Upper & lower lip lengths
The lips are measured independently in a relaxed position.
The normal length from subnasale to upper lip inferior
is 19 to 22mm.
The lower lip is measured from lower lip superior to
soft tissue menton and normally measure in a range of
38 to 44mm.

The closed lip length is misleading and should not be used
Tuesday, March 4, 2014 treatment planning
for

Upper tooth to lip relationship
Conditions of disharmony are produced by 4 variables :Increased or decreased anatomic upper lip length
Increased or decreased maxillary skeletal length
Thick upper lip expose less incisor than thin upper lips, all
other factors being equal.
The angle of view changes the amount of incisor visible to the
viewer.

The distance from upper lip inferior to maxillary incisal edge is measured.
The normal range is 1 to 5 mm. Women show more within this range. Surgical
and orthodontic vertical changes are based primarily on this measurement
Over impaction of upper incisor teeth leads to the appearance of premature ageing,
especially in conjunction with maxillary retraction. This type of surgical movement
Tuesday, March 4, is rarely indicated.
2014

Interlabial gap
With the lips relaxed, a space of 1 to 5mm between upper lip inferior and
lower lip superior is present. Females show a larger gap within the normal
range. This measurement is also dependent on lip lengths and vertical dentoskeletal height.Increase in inter labial gap are seen with anatomic short upper
lip, vertical maxillary excess, and mandibular protrusion with open bite
secondary to cuspal interferences. Decreased interlabial gap is found with
vertical maxillary deficiency, anatomically long upper lip (natural change with
ageing, esp. in males) and mandibular retrusion with deep bite.

An anatomically short upper lip should be recognized as a soft tissue problem and should not
be treated by excessively shortening the maxilla. This can lead to a short, round facial outline

Closed lip position
Even though an understanding of relaxed lip position is
essential, an understanding of closed lip position
adds
support to diagnostic patterns.
The closed lip position also reveals disharmony between
skeletal and soft tissue lengths.

Increased mentalis contraction, lip strain, and alar base narrowing
are observed in vertical skeletal excess, anatomic short upper lip
and in some cases of mandibular protrusion with open bite.

Smile position lip level
Ideal exposure with smile is three-quarters of the crown height to 2mm of
gingiva. Females show more gingival exposure than males.

Excess gingival exposure may be
caused by:a short upper lip,
vertical maxillary excess,
short clinical crown,
and /or large lip elevation

Because of etiological variability surgical shortening of the maxilla is indicated
only when excess gingival exposure is found in combination with increased
interlabial gap, increased incisor exposure, increased lower facial height.


Particular care should be taken with short clinical crowns. A 3 to 4mm
repose incisor exposure may expose unacceptable amounts of gingiva
when smiling

The gingival smile is never treated to ideal at the expense of
underexposing the incisors in the relaxed lip position.


Profile view

Soft tissue profile angle
This angle is formed by connecting soft tissue glabella, subnasale,
and soft tissue pogonion.


Class I occlusion presents a total facial angle range of 165 to 175
degrees. Surgical procedures should generally address the cosmetic
imbalance established with this angle.
The profile angle is the most important key to the need for anteroposterior surgical correction.
When values are less than 1650 or greater than 1750, skeletal
malocclusion needing surgery are probably the cause

Nasolabial angle
This angle is formed by the intersection of the
upper lip anterior and columella at subnasale.
This angle can change noticeably with
orthodontic and surgical procedures that
alter the antero-posterior position or inclination
of the maxillary anterior teeth.
Desirable range of 85 to 105 degrees
As a general rule, the maxilla should not be moved
posteriorly in treating dento-facial deformities,
especially in combination with superior
repositioning.This creates nasal elongation, alar
base depression, and opening of the nasolabial
angle, all of which creates facial premature ageing.



Maxillary sulcus contour
Normally this sulcus is gently curved and gives
information regarding upper lip tension

Maxilla should not be retracted significantly when a deeply
curved thick lip is present since this produces poor lip support.
If possible maxilla should be moved forward into a thick,
curved lip to improve lip support.

Orbital rim
The orbital rim is an antero-posterior indicator
of maxillary position. Deficient orbital rims may
correlate positionally with a retruded maxillary
position because the osseous structures are often
deficient as groups ,rather than in isolation.The
globe normally is positioned 2-4mm anterior
to the orbital rim.

The surgical maxillary versus mandibular decision
is influenced by the orbital rim position. Deficient
orbital rims dictates maxillary advancement, all
other factors being equal.



Cheekbone contour
Cheekbone assessment requires frontal and profile examination
simultaneously. Cheekbone contour (CC) correlates with maxillary
antero-posterior position, frequently the cheek bone contour is
deficient in combination with maxillary retrusion.

This area should have an apex at the cheekbone point (CP) and
not appear flat. The CP is located 20 to 25mm inferior and 5 to
10 mm lateral to the OC.


Throat length and contour

The distance from the neck-throat junction to the soft tissue
menton should be noted .No millimeter measurement is
necessary ,but a planned mandibular setback will
change this length. The predicted esthetic result
should produce a normal appearing length
without sagging.

A patient with a short, sagging throat length is not
a good candidate for mandibular setback. Often a
mandibular setback is necessary with chin augme-ntation to balance lips with chin and maintain throat length.
Suction lipectomy is a useful adjunct for controlling submental sag
with setbacks or when isolated fat accumulation is present.


Chin-neck angle:

Also termed cervicomental angle
Varies between 105-120º



Nasal projection
The nasal projection measured horizontally from subnasale to
nasal tip is normally 16 to20mm ,nasal projection is an
indicator of maxillary antero-posterior position. This length
becomes particularly important when contemplating anterior
movement of maxilla.

Decreased nasal projection contraindicates Maxillary
advancement.
With a class III malocclusion, short nose, and all
Tuesday, March 4,other parts equal, mandibular setback is indicated.
2014

Subnasale - pogonion line ( sn-pg’)
The relationship of lips to the sn-pg’ line is an important aid in
orthodontic soft tissue analysis and treatment. Tooth movement
changes the relationship of the lips to the sn-pg’ line and therefore
the esthetic result.

Burrstone reported that the upper lip is in front of the sn-pg’ line by
3.5mm±1.4mm, and lower lip in front of the line by 2.2mm±1.6mm.
All tooth movements should be assessed in regard to the anticipated
Tuesday, March 4, 2014 change to the sn-pg’ line.
lip

Relationship of the lips to the nose and chin:

In a chin deficient patient, lower lip may
appear full or procumbent



CEPHALOMTRIC
DIAGNOSIS


Soft tissue Cephalometric analysis
Arnett and Bregman presented the Facial Keys to Orthodontic
Diagnosis and treatment planning as a three-dimensional clinical
blueprint for soft tissue analysis and treatment planning.

Cephalometrics for orthognathic surgery
This cephalometric analysis was specially designed for the patient
who requires maxillofacial surgery And uses those landmarks
and measurements which can be altered by common surgical
procedures .

PA view cephalograms
Rickets analysis (rocky mountain)
Grummens analysis


BIOMECHANICAL FACTORS
IN
SURGICAL ORTHODONTICS



It was not untill mid of 20th century ,that refinements in Surgical technique ,
Biological understanding and Antibiotic made surgery a practical
option

Appropriate diagnosis
Treatment planning
Biomechanical principles



Maxillary orthognathic surgery
MAXILLARY SURGERY
IMPACTION
ADVANCEMANT
INFERIOR POSITIONING
SET BACK
SEGMENTATION OF MAXILLA

The level of the osteotomy must also be considered.
The options range from leFort I to LeFort III , with several variations


IMPACTION
The most common indication for maxillary surgery is vertical skeletal dysplasia

The maxilla can be moved upwards by 10 – 15 mm
with excellent stability

Alar cinch
Collins and Epker identified patients who may develop undesirable
nasal aesthetic changes as those who have normal or wide
frontonasal aesthetics before surgery.
These observations led to the development of techniques to ensure
an esthetic reconstruction of alar



The suture is passed from transverse nasalis muscle on one side of
The alar base to the other side and tied to a pre determined width

V-Y Closure
The upper lip when closed in a V-Y fashion , follows the hard tissue
at nearly 1:1 ratio, with prevention of loss of vermilion.



COGS analysis indications include:Increased upper and lower facial height (N-ANS & ANS-Gn)
Increased mandibular plane angle (MP-HP)
Increased posterior facial height (N-PNS )
Increased gonial angle (Ar-Go-Gn)
Increased facial height ratio (N-ANS/ANS-Gn)
Divergent occlusal planes

Clinical presentation:Increased lip to tooth relation
Increased gingival display
Increased inter labial gap relation
Relative mandibular deficiency
Anterior open bite (may be compensated
by hyper eruption of teeth)



Biomechanical factors
Minimize orthodontic extrusion –occurs rapidly with mechanics such
as the placement of low modulus continuous archwires

Segmented arch mechanics are an excellent way to predictably control
the point of force application and the magnitude of force applied

When divergent occ. planes exist the treatment occ. plane must be
selected first , then appropriate force system designed .(typically
a functional occlusal plane is drawn)



If maxillary ant. teeth have erupted significantly beyond the treatment occ. plane
, an extremely efficient orthodontic mechanism for leveling the arch is
the intrusive base arch.

NOTE :Many surgeons perform intermaxillary fixation, orienting the maxilla to
mandible and autorotating the entire maxillomandibular complex to
the desired vertical position , and then using rigid fixation .This will
cause a slight maxillary advancement in addition to impaction.


ADVANCEMENT
The maxilla can be moved forward up to 10 mm.

This movement has 2 limitations:Major limitation to move the maxilla forward is the resistance of the
soft tissues anterior to it (upper lip). It is particularly important in a
patient with cleft lip and palate who are likely to have maxillary deficiency
and are good candidate for maxillary advancement.

Velopharyngeal closure during speech:Failure to achieve a seal to between soft palate and the
posterior pharyngeal wall allows leakage of air through
the nose and causes “cleft-palate speech” in normal
patients.


COGS analysis indications include:Glabella – subnasale ( G-Sn )
Nasion –Point A (N-A)
Nasion –Point B (N-B)
Nasion –pogonion (N-Pg)
Nasion - pogonion (N-Pg’)

Clinical indications:Decreased pharyngeal airway
Excessive submental adipose tissue
Decreased malar convexity
Increased nasolabial grooves



Along with the A-P discrepancy in many pts. varying degree of transverse
discrepancy is found .
Typically a cross bite exists as part of the presenting class III malocclusion

CROSS BITE
DENTAL

SKELETAL

RELATIVE

ABSOLUTE

DIAGNOSIS SK. CROSS BITE:-


PA cephalogram (J point measured to MSR)
Model analysis
Occlusograms

The maxilla can be narrowed or widened perhaps 15mm
,but 10 mm of change is more reasonable expectation.

Techniques for correction:
Maxillary transverse distraction osteogenesis
Surgically assisted RPE
Segmentation of the maxilla

The location of the segmental osteotomy depends on the desired arch
expansion.

Development of inter dental osteotomy site

Segmental root springs

Bracket repositioning with continuous wire can also be used



With an open coil spring ,the roots are brought closer together rather than
farther apart

The most important area in interdental osteotomy is the divergence of roots
not the crowns



Transverse dental constriction
TPA provides an essential method of arch expansion(0.036’’ SS heat treated)

First the TPA should be fitted passively, to assure no unintentional forces ,moments
Or vertical couples

Activation:-

Expand the TPA
Place buccal root torque (to prevent buccal tipping)

Note :- equal amount of torque on both sides to prevent iatrogenic occ. plane cant


Inferior repositioning (down graft)

Technically feasible procedure

Strong tendency for relapse

Inter-positional grafts are required to prevent
the relapse tendency.
Instability may be due to the stretch of the soft tissues created
when the maxilla is moved downward. This would create a
gentle and constant force to move the maxilla back.



COGS analysis indications include:Decreased lower facial height (ANS-Gn)
Decreased mandibular plane angle (MP-HP)
Decreased gonial angle (Ar-Go-Gn)
Increase facial height ratio (N-ANS/ANS-Gn)
Deep overbite

Clinical presentation:Decreased lip to tooth relation
Decreased gingival display
No interlabial gap
Relative prognathism/prominent chin button



Backward movement

Very limited movement is possible (only 3-5mm) due to bony interferences.
Instead the objective is to retract the protruding anterior portion by sectioning
the maxilla and removing the bone across the palate
Then the anterior segments can be brought back posteriorly while the posterior
segments remain in position.



END OF PART - I



CONTENTS ……PART II
Mandibular surgeries:-

Advancement
High angle
Low angle
Setback
Chin surgery

Dentoalveolar surgeries
Implication of incomplete growth
Soft tissue changes
Appliance selection
Retention and stability
Conclusion and references


Surgical orthodontics. /certified fixed orthodontic courses by Indian dental academy

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