2. CONTENTS
Introduction
Clinical examination
Cephalometric evaluation
Extraction vs non extraction
Management of class I malocclusion
Management of class II malocclusion
Management of class III malocclusion
3. INTRODUCTION
“A case is borderline when extraction of permanent teeth is required to reach
a stable and functional occlusion, but when the patient has good facial
esthetics that could be disturbed by extractions.”
Borderline case may also be defined as the case caught in between the
conflict of extraction and nonextraction.
Borderline cases may also have an absence of dental or craniofacial
anomalies, permanent dentition, healthy periodontium and normal
anteroposterior relationship between maxilla and mandible.
4. Clinical Examination
1. Lip separation – increases with tooth prominence.
2. Thick, full lips.
3. Size of nose and chin.
4. Lip strain i.e. lack of well defined labiomental sulcus.
5. Profile: Mild concave / convex.
5.
6. Tooth-size arch length deficiency
(TSALD)
Indices used to find out TSALD.
Carey has set 2.5-5 mm TASLD as a borderline case.
McNamara set arbitrary borderlines of 3-6 mm.
Gust, concluded “amount of maxillary arch length discrepancy
may range from 6 to 8-11 mm for borderline cases. Roughly 1
mm of crowding in either arch to constitute definitive
nonextraction, while definitive extraction therapy in the maxillary
and mandibular arches was 5.8 and 7.3 mm, respectively.
7. Ashley Howes’Analysis
If PMBAW > PMW, then basal arch is sufficient to allow
expansion of premolars resulting in an arrangement of crowded
anterior teeth in a more regular alignment.
PMBAW should be at least 44% of M-D width of teeth anterior to
second molars, if basal arch is sufficient to accommodate all the
teeth.
PMBAW% =
<37% - Basal arch deficiency. Extraction is indicated
37 - 44% - Borderline case
>44% - Non extraction case.
8. Bolton’s discrepancy
In order to achieve a good occlusion with the correct overbite and
overjet, the maxillary and mandibular teeth must be proportional
in size. Bolton (1958) noted a TSD of up-to 4 mm to be a limit of
the anterior reduction. Extraction may be necessary to resolve a
discrepancy greater than this.
9. Peck and peck analysis
Peck and peck analysis takes into account the labiolingual width of the tooth
rather than mesiodistal (MD) width .
Peck and peck analysis is calculated as MD length of mandibular incisor
divided by its labiolingual width. MD and faciolingual (FL) index values for
mandibular central incisor is 88-92 and for mandibular lateral incisors is 90-
95.
Patients with MD/FL indices above the desired ranges may be candidates for
the reproximation. Index values lower than normal range warrant extractions.
10. Irregularity index
Little developed the irregularity index and mandibular anterior
irregularity by adding the linear distances between the five
adjacent anterior contact points.
With perfectly aligned incisors, the score is zero. Little noted a
score >6.5 mm indicates severe irregularity and, thus, the greater
likelihood for extraction.
11. Curve of Spee
Rule of thumb for estimating the resulting loss of arch
circumference is that 1 mm of arch circumference is needed for
each millimeter of curve of Spee depth present.
Fr every 3 mm of curve leveled, arch circumference increases 1
mm.
According to Woods, the amount needed is variable depending on
the type of mechanics used. The deeper the curve of Spee, the
greater the need for extraction.
Roth considered 3-6 mm of curve of Spee mild (1.5-3.0 per side),
and Baldridge added that greater than 6 mm is severe.
12. Cephalometric variables
Skeletal variables
Vertical dimension
Two important angles for the assessment of vertical dimension are
Sella-Nasion and mandibular planes (SN-MP) angle and FMA
angle.
Treatment directed towards achieving facial balance is more
likely to extract in skeletal open bite and not extract in cases with
skeletal deep bite.
13. Dental variables
Incisor mandibular plane angle (IMPA) .Charles tweed noted a
need for “upright” and “vertical” lower incisors to create facial
balance and harmony. He proposed IMPA to be 90° ± 3° in
normal, balanced faces.
A to Pogonion (A-Pog) line McNamara found the proper position
of the mandibular incisor to be 1-3 mm anterior to a line from
point A-Pog in a wel lbalanced face, regardless of age.
14. Steiner set the ideal positions of the maxillary and mandibular
incisors to be 4 mm anterior to the lines connecting Nasion and
point A, and Nasion and point B, respectively.
The maxillary and mandibular incisors should form angles of 22
and 25° to their respective diagnostic lines. Extraction becomes
more likely as incisor positions and angles exceed these values .
15. Tweeds diagnostic triangle
The Tweed’s triangle is made up of the Mandibular plane,
Frankfort horizontal plane and long axes of the mandibular
incisor.
The normal FMIA is 65°
Tweed considered extraction necessary in practically all
dentoalveolar prognathism cases.
When FMA- 20-30°, prognosis for favorable orthodontic results
varies from excellent for those nearing 20° to good for those
nearing 30°.
Reduction of dentoalveolar prognathism will require extraction
where necessary to permit tooth alignment over the basal arches.
16. When the FMA is 30-35°, the prognosis for reducing
dentoalvelolar prognathism varies from good at the 30° to fair at
the 35° value.
When FMA is 35°-40°, prognosis is fair at 35° and unfavorable at
40°.
When FMA is 40° upward, Tweed considered prognosis
unfavorable at 40° and extremely unfavorable at 45°-55°.
In some cases, the removal of teeth in the > 40° range of FMA,
detracts rather than enhances facial appearance.
17. Steiner Compromise
Steiner said that in instances of skeletal discrepancy where it is
not possible to achieve an ideal relationship of 4mm and 22 or 25
degrees to NA and NB line,
If maxillary incisor were inclined a little more lingually and
mandibular incisors little more labially, a well balanced and
harmonious occlusion can be achieved.
For every degree increase in ANB, upper incisor to NA decreases
by 1mm and 1 degree and lower incisor to NB increases by
0.25mm and 1 degree
18. The wigglegram
The wigglegram or “standard-deviation diagram” was first
adapted for orthodontic use by Vorhies and Adams to facilitate the
interpretation of Downs’s cephalometric analysis.
Wigglegram can be used to help make extraction decisions in
borderline cases.
Borderline cases have the following characteristics:
• Absence of dental or craniofacial anomalies.
• Permanent dentition.
• Healthy periodontium.
• Normal anteroposterior relationship between maxilla and mandible
(skeletal Class I).
19. The vertical central line
represents the norms of the
various measurements. Any
values to the left or right of the
central line are either above or
below the average.
The largest and the smallest
acceptable values were plotted
to produce the zigzag lines of
the wigglegram, which thus
depicts the parameters of a
borderline malocclusion.
Conditions that favor
extractions are on the left side,
and conditions weighing against
extractions on the right.
20. The factors are mostly numeric values expressed in degrees,
millimeters or percentages.
Each horizontal increment corresponds to one unit, except for the
nasolabial angle, where the scale is 2° due to the higher standard
deviation.
21. Soft tissue
Position of upper and lower lip
A borderline case with pre-treatment lip protrusion may be better
served with extraction.
Ricketts - the esthetic plane, relating lip position to a line from the
nasal tip to soft tissue pogonion.
In the aging face, lips become relatively more retruded, creating a
natural difference in proper lip positions between different age
groups.
In the adolescent, the lower lip is about 2 mm behind the esthetic
plane, or E line, with a standard deviation of 3 mm.
The adult lower lip is ideal about 4 mm behind the E line with a
similar standard deviation.
22. Burstone considered lip position relative to a line connecting
subnasale and soft tissue pogonion because it is based on a “plane
of minimal variation in the face.”
For each 1 mm of retraction of the upper incisor, the upper lip
retracts 0.75 mm.
Talass et al. found lower values for this ratio which is 1/0.64.
The lower lip retracts by 0.6 mm for every 1 mm of lower incisor
retraction. Thus, retraction of anterior teeth for space closure
makes the profile more concave.
23. Nasolabial angle
According to Burstone’s evaluation of lip relation, a preferable
nasolabial angle value is 73.8° ± 8°.
More recent studies find more suitable values in the range of 90-
115° Extraction of four bicuspids was noted to increase the
nasolabial angle 5.2° by Drobocky and Smith.
Therefore, extraction of teeth in a borderline patient with a
nasolabial angle greater than the normative values should be
avoided.
24. Lip prominence
Holdaway’s soft tissue analysis
linear measurements to assess upper lip morphology and strain. The
thickness of upper lip should be measured in two different areas: 3 mm below
skeletal point A, and from the vermillion border to the labial surface of the
maxillary central incisors.
In normal patients, these two measurements should be approximately the
same (±1 mm). If the vermillion border is thinner than the upper lip near
point A, the lip are considered strained. If the upper lip is thinner than the
vermillion border, the lips are considered flaccid.
In borderline patients with strained lips, the incisors can be retracted
without altering the soft tissue profile because the lip needs to reach normal
form and thickness before retraction. In such patients, extraction is
indicated.
25. The lips would follow tooth movement in borderline patients,
with normal lips.
According to Arnett and Bergman, orthodontists should avoid
extraction in patients with flaccid lips due to the lack of labial
support and the potential for esthetic problems.
26. Factors affecting treatment planning of
borderline cases
Certain types of malocclusion, require additional compliance to ensure
treatment success, so treatment plans based on patient-dependent mechanics
(like intermaxillary elastics, use of headgears etc.) may have their treatment
outcome jeopardized if the patient failed to respond accordingly
27. Tooth-Arch discrepancy
This discrepancy should be evaluated in both the upper and lower
arches. When orthodontists are faced with a marked negative
tooth-arch discrepancy in the lower arch, they may be hard
pressed to treat the patient by performing tooth extractions.
Small negative discrepancies can, in most cases, be treated
without extractions.
Space may be obtained by using leeway space proximal
stripping, correction of pronounced mesial tipping of lower
posterior teeth and small expansions and/or protrusions.
28. Cephalometric discrepancy(CD) and
facial profile
In situations of pronounced labial tipping of the incisors with a
high cephalometric discrepancy and expressive facial convexity,
extractions are often necessary to retract these incisors, improving
the patient's profile.
29. Skeletal age (growth) and
anteroposterior relationships
Maximum pubertal growth spurt occurs approximately at around
11-12 years in girls and 13-14 years in boys.
If a malocclusion can be corrected with growth response (growth
redirection); clinicians can handle the case without extractions
30. Dental asymmetry
Patients presenting with severe dental midline deviation relative to the face
(especially in the lower arch) require tooth extractions.
Small asymmetries can be corrected with intermaxillary elastics or mini-
implants (in some cases, unilateral mechanics), asymmetric extractions,
proximal stripping.
31. Facial pattern
Dolichofacial patients have hypotonic facial muscles in the
vertical direction.
Brachyfacial patients are not as prone to anchorage loss due to
hypertonic masticatory muscles that hinder tooth movement.
Normally dolichocephalics experience greater anchorage loss
than brachycephalics, hence extra care must be taken during
space closure.
32. Pathologies
Patients can have half-formed teeth, agenesis, ectopias, abnormal shapes or
even carious processes, and endodontic lesions that indicate tooth extraction.
During diagnosis these conditions should be considered as they may change-in
certain situations-the choice of the tooth or teeth to be extracted.
33. Extraction vs Non extraction
Since years it has been a key question in planning orthodontic
treatment whether the teeth are to be extracted or not. Two major
reasons to extract are: To provide space to align the remaining
teeth in the presence of severe crowding and to reduce protrusion
or for camouflage in skeletal Class II or Class III situations.
The alternative to extraction in treating crowding is to expand
the arches.
34. Historical background
Extraction of deciduous teeth was known in ancient civilizations
Celsus and Fauchard recommended extraction
First opposition by Hunter in 1771
Extraction of maxillary 1st premolars was routinely done in the early
1800s in the treatment of Class II Div I malocclusions
After initially extracting premolars, Kingsley later gave it up, especially
after Angle renounced it.
Isaac B. Davenport (1887)lectured in New York against extractions
saying that extractions caused “a loss of important organs.”
35. Calvin Case reintroduced it about 1893, arguing that, although the
arches could always be expanded so that the teeth could be placed
in alignment, neither esthetics nor stability would be satisfactory
in the long term.
Edward Angle was also initially a proponent of extractions. Later
he strongly opposed it.
Debate re-opened by Case in 1911.
Appliances by orthodontists such as John Mershon, Joseph
Johnson & George Crozat relied on the non extraction philosophy
helped to perpetuate the philosophy.
36. By the 1960s the Tweed/Begg view had been accepted, and
extraction rates increased dramatically.
From then until the early 1990s there was a continuing decline in
extraction rates, which has stabilized or increased slightly
recently.
Experience has shown that extraction does not necessarily
guarantee stability of tooth alignment and one could argue that if
the results are not very stable either way, there is no reason to
sacrifice teeth.
37. Recently, there has been debate on both sides of the issue of
where teeth should be left during adolescent treatment to
compensate for these documented changes that occur in the aging
face.
The extraction-nonextraction debate is flourishing again.
In 1994, Proffit looked at changes in the extraction rate over the
previous 40-year period. He estimated that the extraction rates
were 30% in 1953, 76% in 1968, and 28% in 1993. (AJO, 2015)
38. General factors affecting extraction
General Factors
1. Medical condition : Bleeding disorders, Bacterial endocarditis,
Anticoagulant medication etc.
2. Age of patient :
Extraction must be considered cautiously in patients with
considerable remaining growth potential (pre-pubertal and
pubertal patients).
Growth of the soft and hard tissues has a significant influence on
the facial results of orthodontic treatment.
A gross facial imbalance could be caused by additional growth of
the nose after appliance removal
39. 3. Patient cooperation : Extraction is avoided in uncooperative
patients.
4. Pathology : Mobile teeth or teeth with less alveolar bone support
and grossly decayed teeth are preferred for extraction.
40. Factors influencing extraction decision
Space requirements in the arch.
Profile of the patient ,soft tissue thickness, posture and thickness of lips,
shape and prominence of nose, ethnicity of the subject, remaining
growth. Remaining active growth and age changes in the soft tissue
integument have important bearing.
In mixed dentition consideration is given to
-molar relationship
-Transverse relation of maxilla and mandible,
-Type of growth
Leeway space
41. Criteria for extraction
According to BUCHIN
Arch length discrepancy of 3–4 mm after 8 years of age
Facial esthetics
Basal bone disharmony – tweed’s triangle, ANB difference
Amount of chin point from NB – NPog
Anchorage requirement
Patient Co-operation
42. According to SALZMANN
Labio lingual dental arch relation to facial plane
Size of the gonial angle
Axial inclination of the mandibular incisors
Type of crowding present
Direction of jaw growth
Basal arch length
Thickness and distribution of soft tissue.
43. Advantages of extraction approach
Stability
Less protrusive facial appearance
Controllable outcomes
Begg philosophy (tooth size reduction required to compensate for
dietary change)
Little gingival recession
44. Advantages of non-extraction approach
Less trauma
Ease of treatment
Consumer demand
Short duration
Facial fullness to give young full profile
Less effect on TMJ
Less effect on the vertical relationship
Less effect on smile width
45. ABSOLUTE CONTRAINDICATIONS OF
EXTRACTION
General contraindications of operations - Acute (cardiac,
pulmonal, cerebral) vascular catastrophe, e.g. myocardial infarct,
coronal thrombosis, stroke, shock.
Haemopoietic diseases (acute leukaemia, agranulocytosis)
Irradiation of jaws (within 30 days before or within 6 months
after radiotherapy).
46. First premolars
It is the tooth most commonly extracted as part of orthodontic
therapy especially for the relief of crowding because:-
1. It is positioned near the center of each quadrant of the dental arch
and since is near the site of crowding, i.e space gained by their
extraction can be utilized for correction both in anterior and
posterior region.
2. First premolars extraction is least apt to upset molar occlusion and
is the best alternative for maintaining vertical dimension.
3. The contact that results between canine and the second premolar
is satisfactory
4. First premolar extraction leaves behind a posterior segment that
offers adequate anchorage for retraction of the 6 anterior teeth.
47. INDICATIONS
1. Teeth of choice for extraction to relieve moderate-severe anterior
crowding in upper and lower arch.
2. Correction of moderate - severe anterior proclination as in Class II
division I or Class I bimaxillary where upper canines have to be
retracted by more than 3-4 mm for good result.
3. When forward positioning of molars is not required to any extent,
the first premolar takes precedence over second premolar as teeth to
be extracted.
4. As a part of serial extraction.
48. Timing of Extraction:
The four first premolars should not be extracted more than 3
weeks before starting active treatment with orthodontic
appliances otherwise the teeth posterior to the extraction spaces
will rapidly migrate mesially thereby leaving insufficient space
for moving anterior teeth back to the positions they should
occupy in the bones of the jaws.
If the 4 first premolars are extracted long before orthodontic
treatment is started, the advantage of having these teeth extracted
is very frequently lost, owing to the closure of the extraction
spaces in this case it is usually necessary to have the 4 first
permanent molars extracted just before starting appliance therapy.
49. SECOND PREMOLARS
INDICATIONS FOR EXTRACTION:
1. When second premolar is excluded completely from the arch due to
forward drift of first permanent molars after early loss of deciduous second
molars.
2. In mild anterior crowding cases, second premolar extraction is preferred
over first premolar as space closure and vertical control is easier after
anterior alignment.
3. Space required for tooth alignment will not fully occupy the extraction
space and the residual space can be closed by controlled mesial movement
of molars without the danger of unwanted retraction of labial segment
which can occur if first premolars are extracted.
50. 4. Second premolar extraction is preferred when one wishes to
maintain soft tissue profile and esthetics.
5. When second premolars are unfavorably impacted
6. When 4-5 mm of anchor loss is deliberately desired
7. If it is grossly carious or periodontally compromised.
8. In open bite cases, second premolar is preferred as it encourages
deepening of bite.
51. Advantages of Second Premolar Extraction
1. Original facial contours can be maintained without reduction of
lip and profile.
2. Maxillary first premolar is frequently a more esthetic tooth
alongside a canine.
3. Less tendency for extraction spaces to reopen in the mandibular
arch.
4. Less possibility of buccal or lingual bone furrows because of
rapid space closure.
5. Easy correction of Class II molar relation to Class I molar
relation
52. Richard Don James did a comparative study of facial profiles in
extraction and non-extraction treatment and compared the pre-
treatment and posttreatment facial profiles of patients who
underwent premolar extraction (108) with those of patients who
did not undergo extraction (62).
The quantitative measurements selected were
(1) an angular measurement —the Z-angle of Merrifield and
(2) a linear measurement —the lower lip to the esthetic line of
Ricketts, the ―E-value.‖ Both the extraction and non-extraction
group facial profile value averages were within the normal range
at the completion of treatment.
53. J.C.Boley etal assessed facial changes in extraction and non-
extraction patients and concluded that there is no significant
difference between post treatment profiles in patients treated with
extraction or non-extraction in both groups.
54. Bishara etal compared dentofacial and soft tissue changes in Class II,
Division 1 cases treated with and without extraction of four first
premolars
He concluded that lip protrusion is an important pre-treatment profile
characteristic that influences the extraction decision in addition to the
presence of a tooth size-arch length discrepancy.
After treatment it was observed that the soft tissue and skeletal
convexities were straighter in the extraction groups more than in the
non-extraction groups; the upper and lower lips were more retruded in
the extraction groups and more protruded in the non-extraction groups
in both sexes,
Upper and lower incisors were retracted and uprighted more among
subjects treated with four first premolar extractions than in the non-
extraction groups.
55. Bowman etal compared esthetic impact of extraction and non-
extraction treatments on Caucasian patients. Panels of 58
laypersons and 42 dentists evaluated randomly presented pre- and
posttreatment profiles of 70 extraction and 50 non-extraction
Caucasian patients. Results showed that extraction patients‘ faces
were, on average, 1.8 mm flatter‘‘ than the faces of non-extraction
subjects. Study concluded that extraction as being potentially
beneficial when the lips were more protrusive than 2 to 3 mm
behind Ricketts‘ E-plane.
56. Kim etal compared arch width changes in the anterior and
posterior parts of the arches as well as smile esthetics in patients
treated by extraction and nonextraction procedures.
The study concluded that the average arch width of both arches
was significantly wider in the extraction sample (1.8 mm wider in
the mandible and 1.7 mm wider in the maxilla).
Arch width is not decreased at a constant arch depth because of
extraction treatment, and smile esthetics are the same in both
groups of patients.
57. Meyer, etal found a significant increase in the posttreatment
maxillary intercanine width in the extraction group.
Arch widths between the maxillary first molars and at the level of
the posterior rugae were greater in the non-extraction group.
No significant differences in any buccal corridor widths were
measured between the extraction and non-extraction subjects.
58. Management of borderline skeletal
malocclusions in growing individuals
Functional appliances: Class II cases treated with the fixed functional
appliances requires a subsequent dental alignment treatment phase with a
multibracket appliance.
Treatment effects on the dentofacial complex: The improvement in sagittal
occlusal relationships is the equal result of skeletal and dental changes.
Occlusal changes: The dental change is the result of anchorage loss in the
maxillary and mandibular arches. Posteriorly directed forces in maxilla
distalise maxillary teeth while anteriorly directed forces in mandible
mesialise mandibular teeth.
59. Clinical application of orthopaedic forces in
class I malocclusion
When there is arch length / tooth size discrepancy , patient is treated in
early mixed dentition by either serial extraction or orthopaedic
expansion.
Headgears are used when maximum anchorage is needed to maintain
the existing Arch Length.
Maxillary skeletal protrusion
Is treated by extraoral traction.
Cervical (low pull) face bow is used in patients with decreased VD
(Kloehn, Graber, Weislander) .
Occipital (high pull) face bow: Used in patients with increased VD.
60. Maxillary skeletal retrusion:
They have increased lower facial height, a steep mandibular
plane angle, and a retruded position of chin point.
Treated by vertical pull chin cup which produces upward &
forward movement of maxilla & counter clockwise rotation of the
mandible.
Maxillary dento-alveolar protrusion :Flared upper incisors are
retracted using a High–Pull HG or Straight pull combined with J–
Hooks or a closing Arch supported by headgear.
61. Mandibular skeletal retrusion
Treated by functional jaw orthopedics which includes forward
posturing of the mandible. Eg. FR2, Bionator, Herbst.
62. Use of orthopaedic forces in class II
backward rotators
1. In mixed dentition open–bite patients.
2. Useful in Extraction cases.
3. Use of mandibular bite blocks combined with vertical pull chin
cup.
4. Intrusive forces with fully banded appliance along with occipital
pull HG help in controlling the VD
63. Class III malocclusion
Treatment of maxillary deficiency
1. Reverse pull head gear or protraction head gear by Hickham
2. Face mask by Delaire
3. Sub-orbital protraction appliance: Developed by Grummons,
Zygomatic arch areas support the appliance, no force exerted on
TMJ. Easy to adjust and comfortable to wear during sleep.
4. Maxillary protraction bow appliance (MPBA Therapy)
64. Extra oral forces in functional appliances
Activator - Head gear combination:
Extraoral force in frankel appliance
Orthopaedic traction in twin Block
65. Management of borderline dentoalveolar
malocclusions in non-growing individuals
Black was amongst the pioneers who described natural slenderization in 1902.
Ballard first described a technique to reduce the tooth material by reducing
the enamel.
Peck –reproximation.
Techniques
1. Abrasive strips: it is too laborious and time consuming.
2. Hand piece mounted reducing discs : because of its close proximity with tongue and
other soft tissue like lips and cheek they can be dangerous.
66. Techniques
3. Air-rotor stripping: first described by Sheridan. Air rotor
stripping involves the use of a fine air rotor diamond cutting bur
attached to the headpiece to reduce interproximal enamel for
alleviation of mild to moderate crowding. The space generated by
air-rotorr striping does not have to be estimated. It can be measured
with commercially available gauges. A conservative guideline is to
remove no more than .75mm of interproximal enamel between the
anterior contact points and no more than 1mm from the posterior
contact points.
4. Intensive Orthostrip system (GAC): It involves the use of hand
piece driven abrasive strips with different configuration and abrasive
potential the instrument removes enamel by back and forth shuttle
action. Flexible blades (proxy shape) are also used to contour and
smooth the reduced proximal surface with abrasive grain size of
different dimensions.
67. Molar Distalization
Indications
1. Minimal arch length discrepancy cases and mild class II molar
relationship associated with normal mandible.
2. Borderline cases can be effectively managed without extracting
teeth, thereby gaining space required for the needful corrections.
3. Class II div I with low mandibular plane angle.
4. Blocked out or impacted canines due to mesial drift of molars but
having good aesthetic profile can be treated.
68. Contraindications
1. Patients with severe arch length tooth size discrepancy.
2. Patients having high mandibular angle are contraindicated for
distalization of molars.
3. Treatment by distalization is also difficult in fully grown
patients. Anterior anchorage loss can occur due to the forces
required for distalisation of third molar.
4. According to William Wilson in 1978, molar distalization
should not be done before 11 years of age as the maxillary
tuberosity enters its rapid growth phase which may lead to second
and third molar impaction.
69. Various molar distalisation appliances can be classified as
(a) Extra-oral appliances;
(b) Intra-oral appliances.
70. Extraoral
In 1822, Gunnel first described
Extra-oral anchorage. In 1866,
Guilford used the headgear for
correcting protruding maxillary
teeth. Further, in 1892 Norman
William Kingsley reported
remodeling of class II molar
relationship to class I using
headgear. Later, Klein Phillip in
1957 assessed the outcome of
cervical traction for correcting
class II malocclusion.
Intraoral
Atikinson Buccal Bar,
Herbst Appliance,
Jasper Jumper,
Pendulum And Pendex Appliance,
Mini Distalization Appliances,
Distal Jet Appliances,
Wilson's Distalizing Arch (Bimetric
Distalizing Arch),
Repelling Magnetic Appliance, K-
Loops,
Distalization In lower Arch
Lip Bumper, Modified Lingual
Appliance, Distal Jet.
71. Maxillary expansion
Slow expansion devices Active plates for arch expansion Active
plates are most useful when only a few millimeters of space are
needed.
Quad Helix Appliance
Indications 1. All cross- bites in which the upper arch needs to be
widened
2. Mild expansion in the mixed dentition which frequently exhibit
lack os space for the upper laterals and in which the long range
growth forecast is favorable.
3. Class III - Expansion needed
4. Class II cases
5. Thumb sucking or Tongue thrusting cases
72. Rapid maxillary expanders
Common appliances
1. Derirshweiler type: Tags are welded and soldered to the palatal aspects of
the bands to provide attachment for the acrylic which is also extended to the
palatal aspects of all non banded teeth, except the incisors.
2. Hass type: A length of 0.045inch (1.5mm) stainless steel wire is welded and
soldered along the palatal aspects of the bands. The free ends are turned back
and embedded in the acrylic base which stops short of the bands and teeth. A
proprietary screw is set in the midline of the split acrylic base.
3. Issacson type: This appliance uses a special loaded screw called a Minne
expander which is adapted and soldered directly to the bands without the use of
acrylic. The screw may be reduced in length to suite narrow arches by
shortening the spring, tube and rod.
4. Bidermann type: This appliance requires a special screw either Hyrax
(Dentarum 602-813) Leaone 620 or Unitex 440-160. These have extension in
heavy gauge wire where they are welded and soldered to the palatal aspects of
the bands.
73. Jackscrew Turn Schedules
Zimring and Isaacson recommend the following turn schedules:
1. Young growing patients two turns each day for the first 4 to 5
days, one turn each day for the remainder of RME treatment:
2. Adult (non growing) patient - because of increased skeletal
resistance, two turns each day for the first 2 days, one turn each
day for the next 5 to 7 days, and one turn every other day for the
remainder of RME treatment.
74. Surgically assisted maxillary expansion
Indications
1. A skeletal maxillomandibular transverse discrepancy greater than
5mm .
2. Significant transverse maxillary deficiency associated with a
narrow maxilla and wide mandible;
3. Failed orthodontic expansion.
75. 4. Necessity for a large amount (>7mm) of expansion, or preference
to avoid the potential increased risk of segmental osteotomies;
5. Extremely thin, delicate gingival tissue or presence of significant
buccal gingival recession in the canine-bicuspid region of the
maxilla; and
6. Significant nasal stenosis.
76. Uprighting of posterior teeth
Tilted posterior teeth always occupy more space. Molars tend to
tip mesially when the deciduous second molars are lost early or
decay on the distal surface of this tooth is on/not restored at the
appropriate time or with the ideal contour.
A delayed eruption of the first or the second molar may also cause
the posterior teeth to till mesially.
Uprighting of molars can lead to an arch length gain of 11.5 mm.
Fixed appliances are used for the purpose.
Space regainers or the various screw appliances are also used
frequently.
77. Derotation of posterior teeth
Rotated posterior teeth can help regain this space. The space
regained varies upon the tooth concerned and the extent of
rotation.
For a similar degree of rotation, the molars occupy more space as
compared to premolars, whereas rotated anterior teeth occupy less
space. Derotation can be best achieved using a couple (forces
equal in magnitude but opposite in direction) on the lingual and
buccal surfaces of the tooth. Any fixed appliances system with a
two point contact has more efficient rotation control.
78. Proclination of anterior teeth
Can be undertaken in cases where these teeth are retroclined.
The proclination springs (“Z” spring, mattress spring,etc.) or
fixed appliances can be used for the purpose.
79. Management of borderline skeletal malocclusions
in non-growing individuals who require surgical
intervention .
TAD’S
Indications
1. Maximum anchorage cases
2. Patient with several missing teeth making it difficult to engage
posterior units
3. For difficult tooth movements, eg intrusion of anterior and
posterior segments and distalisation
4. Where asymmetrical tooth movement is needed
5. To treat borderline cases with non extraction method
80. Camouflage or Surgery?
One of the most difficult decisions facing the orthodontist and
surgeon is whether a patient with a borderline skeletal
discrepancy can be successfully treated with orthodontics alone.
This is a very critical decision and must be made from the very
beginning, because the tooth movement needed for surgery often
is just the opposite of what would be needed for orthodontic
treatment alone.
81. The envelope of discrepancy should be considered a starting point
in making this decision.
It gives the limitations of orthodontic treatment in terms of
whether the occlusion could be corrected, not whether the
deformity could be camouflaged.
For a patient whose deformity is within the envelope, the decision
must be made in the context of the esthetic impact of the two
forms of treatment.
82. Envelope of discrepancy.
(Proffit & Ackerman)
It shows the amount of change in all 3 planes of space that
could be produced by
1. Orthodontic tooth movement alone
2. Orthodontic tooth movement combined with growth
modification in a growing child
3. Orthognathic surgery.
83. Key features:
The possibilities for each type of treatment are not symmetric
with regard to the planes of space.
More potential to retract than procline teeth.
More potential for extrusion than intrusion.
More tooth movement is possible anteroposteriorly than
vertically.
Growth modification is more effective in mandibular deficiency
than in mandibular excess.
Surgery to move the lower jaw back has more potential than
surgery to advance it.
84. Envelope of discrepency thus outlines the limit of hard tissue
change toward ideal occlusion, if other limits due to the major
goals of treatment do not apply.
Drawback: soft tissue limitations not reflected in the envelope of
discrepancy are often a major factor in the decision for
camouflage or surgical-orthodontic treatment.
85. This is where the patient`s input must be thought and where
computer simulations that the patient can understand are
particularly valuable.
Only the patient can decide whether the esthetic difference
between surgical correction of the jaw deformity and orthodontic
correction of the malocclusion would be worth it, in terms of the
additional risk and cost of surgery.(cost- benefit
86.
87. For patients with mild to moderate skeletal class II problems,
displacement of the teeth relative to their bony bases to achieve
good occlusion is compatible with reasonable facial esthetics and
the camouflage can be quite successful.
In the severe class II problems, it may be possible to obtain good
occlusion only at considerable expense to facial esthetics.
Camouflage also can be used in patients with mild skeletal class
III problems in whom adjustment of incisor position can achieve
acceptable occlusion and reasonable facial esthetics.
Unfortunately in even moderately severe skeletal class III
malocclusion, camouflage is much less successful.
88. .
Good candidates for camouflage treatment are…..
Too old for successful growth modification.
Mild to moderate skeletal class II.
Mild skeletal class III.
Reasonably good alignment of teeth so that extraction space
would be available for controlled anteroposterior displacement.
Good vertical facial proportions, neither extreme short or long
face.
89. Poor candidates for camouflage treatment
are…..
Severe skeletal discrepancy or extreme dentoalveolar problems.
Patients with severe crowding or protrusion of incisors where
extraction spaces will be used to achieve proper alignment of the
incisors.
Patients with excellent remaining growth potential in whom
growth modification treatment should be used.
Non growing adults with more than mild discrepancies where
surgery offers better long term results.
90. Guidelines relative to camouflage…….
Patients with a long face or skeletal open bites….
Difficult to treat orthodontically regardless of growth status.
Orthodontic mechanotherapy extrudes teeth somewhat and in long face
patients will result in downward mandibular rotation further
lengthening the face.
If an open bite was not present initially it frequently develops in the
course of leveling the arches.
Since straight wire features were designed to produce ideal dental
relationships, one may see varying degrees of A-P, Vertical and
Transverse discrepancy develop as dental compensations for the
skeletal problem are removed by appliance prescription.
All these features complicate camouflage treatment for this type of
patient tipping the balance towards surgery in apparently borderline
situations.
91. Patients with a short face or skeletal deep bites
Amount of arch length discrepancy
Soft tissue relationships
Problems in transverse dimensions
92. Camouflage vs Surgery in Class II patients.
The boundary between orthodontic and surgical treatment is
particularly troublesome for teenagers with class II problems given the
risk of camouflage failure vs. the greater cost and morbidity of surgery.
Although no clinical trial has occurred, some data now are available to
more clearly indicate the limits of camouflage and therefore the
indications for surgery for post adolescent class II patients.
For an individual who is past the adolescent growth spurt, the best
single indicator of a problem too severe for likely success with
camouflage is, greater than 10 mm of overjet.
Two other factors to consider the decision between orthodontics vs.
surgery are the possible role of
augmentation genioplasty as an adjunct to class II camouflage and
the risk of root resorption with camouflage.
93. A limiting factor in class II camouflage is the extent to which the
lower teeth can be moved forward relative to the mandible.
More than 2mm forward movement – highly unstable.
An alternative is a lower border osteotomy to reposition the chin
which can both improve facial balance and decrease lip pressure
against the lower incisors improving their stability.
The lower border osteotomy is no more extensive a surgical
procedure than premolar extraction would be, and it can be done
as an outpatient or day op procedure at much less cost than
mandibular advancement.
94. Camouflage vs Surgery in Class III patients.
Turpin (1981) developed positive & negative factors for deciding when to
intercept a developing class III malocclusion.
Positive factors – Good facial esthetics, mild skeletal disharmony, no familial
prognathism, symmetric condylar growth, growing patients with good
cooperation.
Negative factors – Severe skeletal disharmony, poor facial esthetics,
asymmetric condylar growth, growth complete.
Early treatment is considered for patient with positive factors.
The best way to correct a jaw discrepancy would be to get the patient grow out
of it.
The important question in planning treatment are the extent to which growth
can be modified, and how advantageous it is to start treatment early.
The answers are almost as controversial as extraction- nonextraction.
95. Musich proposed the use of serial cephalometric radiographs and
GTRV (growth treatment response vector) analysis to predict
excessive mandibular growth.
This analysis warns of excessive mandibular growth after early
orthopedic treatment.
Norm for patients between 6-16 years – 0.77.
96. Horizontal growth changes of
maxilla and mandible between
posttreatment radiograph and
follow-up radiograph were
determined by locating A-point
and B-point on first radiograph.
Occlusal plane (O) was
constructed by using
mesiobuccal cusp of maxillary
molars and incisal tip of
maxillary incisors as landmarks.
Lines AO and BO were then
constructed by connecting
Points A and B perpendicular to
occlusal plane.
97. First tracing was superimposed
on follow-up radiograph by
using stable landmarks on
midsagittal cranial structure.
Distance between A-point of 2
tracings along occlusal plane
represents growth changes of
maxilla, and distance on
occlusal plane of B point
represents growth changes of
mandible. GTRV ratio was then
calculated.
98. A study of 20 patients who were successfully treated with facemask
therapy and 20 patients who were unsuccessfully treated
The mean GTRV ratio for the successful group was 0.49 with a
range of 0.33 to 0.88.The mean GTRV ratio for the unsuccessful
group was 0.22 with a range of 0.06 to 0.38.These results suggest
that Class III patients with mild to moderate skeletal patterns with a
GTRV ratio between 0.33 and 0.88 can be successfully
camouflaged with orthodontic treatment. Class III patients with
excessive mandibular growth and a GTRV ratio below 0.38 should
be warned of the need for future orthognathic surgery.
99. Conclusion
The borderline cases are our greatest responsibility. They are the
most sensitive.
In an extreme malocclusion, the patient may profit greatly from
treatment, even if treatment is not done in what we would
consider to be a most satisfactory way.
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