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Class III malocclusion seminar
2. CLASS III
MALOCCLUSION
Presented by:
Dr. Khushbu Agrawal
Guided by:
Dr. Suresh Kangane
Dr. Anand Ambekar
Dr. Pravinkumar Marure
Dr. Yatishkumar Joshi
Dr. Chaitanya Khanapure
4. INTRODUCTION
Edward Angle classified malocclusion in 1899 based on
anteroposterior relationship of the jaws with each other
as –
CLASS I CLASS II CLASS III
4
5. CLASS III MALOCCLUSION
Prenormal occlusion or
mesioclusion
‘Mesial’ or ‘ventral’
relationship of maxilla to
mandible
The mesial groove of
mandibular first permanent
molar articulates anteriorly to
the mesiobuccal cusp of
maxillary first permanent
molar
Handbook of orthodontics by Robert Moyers; 4th edition
Introduction…
5
6. 1.True or skeletal class III
▪ mandibular hypertrophy
▪ Marked shortening of
midface
▪ combination
Handbook of orthodontics by Robert Moyers; 4th edition6
A] Angle classified –
CLASSIFICATION
7. 2. Pseudo or functional or postural
class III
▪ Occlusal prematurities
▪ Premature loss of deciduous
posteriors
▪ Enlarged adenoids
3. Class III , Subdivision
▪ Class III on one side and class I on
other
Handbook of orthodontics by Robert Moyers; 4th edition7
Classification…
9. C] Tweed’s divided into 2 categories –
• Large mandible
• Normal maxilla
Skeletal
Class III
• Normal mandible
• Underdeveloped
maxilla
Pseudo Class
III
Classification…
Textbook of orthodontics by Dr. Samir Bishara
9
10. D] Moyer’s classification –
[According to the cause]
1. Osseous (Skeletal)
2. Muscular
3. Dental
Classification…
Textbook of orthodontics by Dr. Samir Bishara
10
11. Variants of Skeletal Class III
From Ngan P et al (AJODO 1996;109:38-49)
11
Classification…
Textbook of orthodontics by Dr. Samir Bishara
12. Caucasians – 1% to 4%
Africans-Americans – 5% to 8%
Asians –
Japanese 4% to 13%
Chinese 4% to 14%
Indians 4.1%
Textbook of orthodontics by Dr. Samir Bishara
12
FREQUENCY
(Oommen Nainan et al, J Ind Orthod Soc 2013;47(4):328-34)
13. ETIOLOGY
1) HEREDITY
McGuigan described most well known example of
genetic influence, the Hapsburg family, having
distinct characteristics of prognathic lower jaw
2) ENVIRONMENTAL INFLUENCES
Rakosi and Schilli suggested role of habits and mouth
breathing (J.Oral Surg 1981;39:860-70)
13
Textbook of orthodontics by Dr. Samir Bishara
14. 1.FUNCTIONAL
• Abnormal tongue
position, nasal-
respiratory
problems,
neuromuscular
conditions
2.SKELETAL
• Maxillary
transverse
discrepancy,
excess
mandibular
growth
3.DENTAL
• Ectopic eruption
of maxillary
central incisors,
early loss of
deciduous molars
( Hindawi Publishing Corporation vol 2014 )
14
According to ARIEL et al
15. CLINICAL FEATURES
A] Extraoral features :
1. Concave profile
2. Anterior facial divergence
3. Retrusive nasomaxillary area
4. Prominent lower third of
face/chin
5. Steep mandibular plane angle
15
16. B] Intraoral features :
1. Class III molar and canine
relationship
2. Narrow upper arch
3. Decreased or reverse overjet
4. Crowding in upper arch and
spaced lower arch 16
17. DIAGNOSIS
▪ Case history
▪ Photographs
▪ Study models
▪ Radiographs
▪ Cephalometric analysis
17
Textbook of orthodontics by Dr. Samir Bishara
19. Profile Assessment :
1. Facial proportions
- Straight, convex or concave
- Maxillary deficiency shows
concave profile, flattening of
infraorbital rim
19
20. 2. Chin position
- Chin should not be positioned
anterior to a vertical line extending
down from soft tissue glabella
- Facial convexity decrease with age
20
21. 3. Mid-face position
- an imaginary line extending from inferior
border of the orbit through the alar base of
nose and down the corner of mouth
- A straight or concave tissue contour
indicates midface deficiency
21
22. 4. Vertical proportions
- Checked in CO and CR
- Normal ratio for lower facial height to total facial
height is 0.55
- Decreased in patients with functional shift and
overclosure of mandible
22
26. Beta angle more than 35 degree
W angle
Smaller Articular angle
Greater saddle angle
26
Diagnosis…
27. 27
Shendre Shrikant et al conducted a cephalometric study to
study anteroposterior relationship of jaws and dental arches
in Class I, Class II, and Class III malocclusion
(Int J Contemporary Dentistry March 2011;2(2))
Diagnosis…
28. 28
Hyung-Jun Choi conducted a cephalometric study to compare
between characterstics of Class III malocclusion in Korean
children with deciduous dentition. (Angle Orthod. 2010;80:86–90)
He concluded that –
1. The relative sagittal position of the maxilla and mandible
(ANB difference, facial convexity, Wits appraisal) showed
highly significant differences
2. The mandibular length is greater in class III children with
maxillary length showing no such difference
Diagnosis…
29. 29
3. The saddle angle and ramus height are greater while
articular angle is smaller for Class III
4. The maxillary incisors show proclination and mandibular
incisors show retroclination
5. Large interincisal angle
6. Greater soft tissue convexity
Diagnosis…
30. 30
Kwong and Lin conducted a cephalometric study comparing
characteristics of patients with Class I, Pseudo Class III, and
skeletal Class III malocclusion (Clin Dent, 1987 7(2):69-78)
Diagnosis…
31. 31
• No sagittal skeletal discrepancy
• ANB angle normal
• Lingual tipping of maxillary incisors
• Labial tipping of mandibular incisors
Class III caused by
Dentoalveolar
Malrelationship
• ANB angle is negative
• Large gonial angle
• Labial tipping of maxillary incisors
• Lingual tipping of mandibular incisors
Skeletal Class III with
Mandibular
Protrusion, Maxillary
Retrusion or Both
• Gonial angle similar to Class I
malocclusion
• Other cephalometric features
intermediate between Class III and Class I
Pseudo Class III
Malocclusion
Textbook of orthodontics by Dr. Samir Bishara
Diagnosis…
32. DIFFERENTIATING A DENTAL CROSSBITE
FROM A SKELETAL CROSSBITE
32
DENTALASSESMENT
(Molar relationship and overjet)
Class III molar relationship
Positive overjet or end-to-end
incisal relationship with
retroclined mandibular incisors
Class III molar relationship
Negative Overjet
FUNCTIONALASSESMENT
Compensated Class III
malocclusion
Pseudo Class III
malocclusion
True Class III
malocclusion
CR-CO ShiftNo CR-CO Shift
Textbook of orthodontics by Dr. Samir Bishara
Diagnosis…
33. CLASS III SKELETAL GROWTH PATTERNS
1. Cranial base (Battagel, EJO 1993)
- Decreased linear and angular
measurements
- Middle cranial fossa shows posterior
and superior alignment
- Retrusive nasomaxillary complex
- Forward rotation of mandible
33
Textbook of orthodontics by Dr. Samir Bishara
Diagnosis…
34. 2. Maxilla
- Decreased horizontal growth
- Horizontal movement of “A-point” is approximately 0.4 mm/yr
(1 mm/yr in Class I patients)
3. Mandible
- Increased mandibular length
- Shorter ascending ramus with steep mandibular plane angle
- Obtuse gonial angle
34
Textbook of orthodontics by Dr. Samir Bishara
Diagnosis…
35. 4. Growth increments
- Sugawara and Mitani said Class III skeletal pattern was
established at a young age and does not change
fundamentally
- Total increase in posterior cranial base is less in patients
with prognathic mandible
- Also, different growth changes in males and females
- Females patients show more prominent mandible and an
increased proclination of maxillary incisors
35
Textbook of orthodontics by Dr. Samir Bishara
36. Rabie and Yan Gu (AJODO 2000) identified the
diagnostic criteria for Pseudo–Class III malocclusion
and compared it with Class I malocclusion in the
southern Chinese population
36
PSEUDO CLASS III MALOCCLUSION
37. CLINICAL FEATURES:
1. Majority showed no family history
2. Class I molar and canine relationships at HO and Class
II or end to end relationship at CR
3. Decreased midface length
4. Forward position of the mandible with normal mandibular
length
5. Retroclined upper incisors and normal lower incisors
37
38. TREATMENT OF PSEUDO CLASS III
Removal of CO-CR discrepancy – avoid normal wear and
traumatic occlusal forces to affect the teeth
Removes potential adverse effects on growth of jaws
Establishes good functional occlusal
Improves facial aesthetics
38
42. TREATMENT OF TRUE CLASS III
Why should the treatment be started
early ? (By Renato et al, J Appl Oral Sci 2015;23(1):101-9)
Facilitates the eruption of canines and
premolars in a normal relation
Eliminates the traumatic occlusion of incisors
Provides an adequate maxillary growth
Improves the self esteem of the child
42
43. 43
Textbook of orthodontics by Dr. Samir Bishara
GOALS OF
EARLY
INTERCEPTION
Preventing
progressive,
irreversible,
soft tissue, or
bony changes
Improving
skeletal
discrepancy
Improving
occlusal
function
Simplifying
phase II
comprehensive
treatment
Providing more
pleasant facial
aesthetics
Treatment…
44. 44
According to Turpin et al (1981) –
- Good facial aesthetics
- Mild skeletal disharmony
- No familial prognathism
- Anteroposterior functional
shift
- Convergent facial type
- Symmetric condylar growth
- Growing patients
- Expected good cooperation
- Poor facial aesthetics
- Severe skeletal disharmony
- Familial pattern established
- No Anteroposterior shift
- Divergent facial type
- Asymmetric growth
- Non-growing patients
- Expected poor cooperation
EARLY
TREATMENT
TREATMENT
DELAYED
Textbook of orthodontics by Dr. Samir Bishara
Treatment…
46. Indications :
Mild to moderate skeletal discrepancies
Growing patients
Preliminary treatment before major fixed appliance
therapy
Decreased lower facial height
Post treatment retention
46
MYOFUNCTIONAL APPLIANCES
Treatment…
*Dentofacial orthopaedics with functional appliances byGraber and Petrovic
47. Treatment principles :
1. Force application
- Compressive stress and strain act on the structures
involved resulting in primary alteration in form with
secondary adaptation in function
2. Force elimination
- Elimination of abnormal or restrictive environmental
influences on dentition
- Teeth respond to reduced force by setting up new
balance
47
Treatment…
*Dentofacial orthopaedics with functional appliances byGraber and Petrovic
51. 4. FRANKEL III REGULATOR (FR III)
More successful in patients with
functional shift on closure
Increased overbite of 4-5 mm
Early mixed dentition
Also, as a retentive device after
maxillary protraction
51
Textbook of orthodontics by Dr. Samir Bishara
Treatment…
53. 1. FACE MASK
Used in patients with mild to
moderate Class III with maxillary
retrusion
2 pads connecting soft tissue in
forehead and chin region
53
ORTHOPAEDIC APPLIANCES
Treatment…
Textbook of orthodontics by Dr. Samir Bishara
54. Design and construction :
- 2 pads connecting soft tissues in
forehead and chin region with a metallic
framework
- Elastics attached near the maxillary
canine region with a downward and
forward pull of 300
to the occlusal plane
- Metallic banded or acrylic bonded palatal
expansion plate can be attached
54
Treatment…
Textbook of orthodontics by Dr. Samir Bishara
55. Force magnitude and direction:
- Orthopedic force of 300-600 g/side
- 10-12 hours/day
- Force directed 5mm above the palatal plane
- 30 to 450
protraction force applied at maxillary canine region
Treatment timing:
- Primary or early mixed dentition period
- Mostly at the time of initial eruption of maxillary centrals
- Duration may vary from 3-16 months 55
Treatment…
Textbook of orthodontics by Dr. Samir Bishara
57. 57
A study by Renato et al (J Appl Oral Sci 2015;23(1):101-9)
Rapid maxillary expansion followed by facemask therapy was
performed, to correct the anteroposterior relationship and
improve the facial profile in a 7.6 year old patient
Treatment…
59. 2. CHIN CUP
Used in skeletal Class III
malocclusion with a relative
normal maxilla and a
moderately protrusive mandible
Two types:
- Occipital pull
- Vertical pull
59
Textbook of orthodontics by Dr. Samir Bishara
Treatment…
60. Effects on growth:
A) Mandible
- Redirection of mandibular growth vertically
- Backward repositioning or rotation
- Remodeling with closure of gonial angle
- Posterior movement of Point B and Pogonion
A study by Graber showed that the use of a chincup promoted a
backward movement of Point B, due to a clockwise rotation of the
mandible. (AJO 1977)
B) Maxilla
- Prevents retardation of Anteroposterior maxillary growth
60
Textbook of orthodontics by Dr. Samir Bishara
Treatment…
61. Force magnitude and direction:
- Orthopedic force of 300-500 g per side
- 14 hours/day
- Directed usually through condyle or below the condyle
Treatment timing:
- Primary or early mixed dentition
- Treatment time varies from 1 year to 4 year depending
on severity
61
Textbook of orthodontics by Dr. Samir Bishara
Treatment…
63. ESCHLER APPLIANCE
Also known as “progenic appliance”
Appliance design : (Marcio et al, J Appl Oral Sci 2011)
- Retention clasps e.g. Adams clasps for molars, and
intermolar auxiliary clasps for deciduous teeth and
premolars
- An eschler labial bow, made in 0.9-mm wire, and
adapted at the labial surface of the lower incisors
- An occlusal bite-raising appliance in acrylic resin
with a thickness of 2 to 3 mm
63
Treatment…
64. 64
A Case Report By Marcio Rodrigues de ALMEIDA et al
(J Appl Oral Sci 2011,19(4):431-9)
A 9 year old patient with chief complain of anterior crossbite
treatment by chin cup and eschler appliance
1st phase – interceptive,treated by chin cup and eschler appliance
Treatment…
65. 65
2 years later, 2nd phase – Corrective, to correct the
increasing midline diastema in permanent dention.
Lasted 14 months
Pre-treatment and post
treatment cephalometric
superimposition tracing
66. TANDEM APPLIANCE
By Chun et al, 1999
Appliance design : (By Leon Klempner, JCO 2011)
- Intraoral appliance with one fixed and two
removable components
- Upper section is fixed Hyrax, Hass or Quad
helix with buccal arms soldered for
attachment of protraction elastics
- Lower similar to removable retainer, with
posterior occlusal cover- age and buccal
headgear tubes embedded in the lower
first-molar regions
66
Treatment…
67. 67
Treatment…
Advantages :
(By Pravinkumar S Marure, J Ind
Orthod Soc 2014)
Highly aesthetic
Patient friendly
Easy maintenance of
oral hygiene
Treatment can be
suspended or
restarted according
to clinician
68. 68
A CASE REPORT BY Dr. Pravin Kumar S Marure et al
(J Ind Orthod Soc 2014;48(3):198-205)
A 9 old year patient with dental Class I and skeletal Class III
Treatment…
69. ORTHODONTIC CAMOFLAGE
Indications :
Skeletal discrepancies not resolved during mixed
dentition
Malocclusions recurring during adolescence after
treatment in childhood
Mild mandibular prognathism and moderate crowding
Types :
With extractions
Without extractions
69
Treatment…
Textbook of orthodontics by Dr. Samir Bishara
70. Depending on the malocclusion extraction can be done
as follows:
Two lower premolars or a mandibular incisor
All four premolars
Maxillary 2nd and mandibular 1st premolars
Mandibular second molars
[By Jiuxiang Lin, Angle Orthodontist 2006;76(2)]
70
Textbook of orthodontics by Dr. Samir Bishara
Treatment…
71. Class III elastics :
From upper molar to lower
anteriors
Corrects molar relation by
moving the molar mesially
Retraction of lower
anteriors
71
Textbook of orthodontics by Dr. Samir Bishara
72. ORTHOGNATHIC SURGERY
Indications :
Continued disproportionate sagittal and vertical growth
Severe skeletal maxillary retrusion and mandibular
prognathism or both
Non-growing patients
Cleft lip and palate
Facial asymmetries
72
Treatment…
73. Steps involved :
1. Diagnosis
2. Pre-surgical orthodontics (decompensation)
3. Mock surgery
4. Surgery and stabilization
5. Post-surgical orthodontics
73
Treatment…
74. Mandibular prognathism :
1. Mandibular ramus osteotomy
(BSSO)
2. Mandibular inferior body
osteotomy
74
Textbook of orthodontics by Dr. Samir Bishara
Treatment…
75. Maxillary retrusion :
Le Fort I osteotomy with maxillary advancement
75
Textbook of orthodontics by Dr. Samir Bishara
Treatment…
77. 77
A 22 year old patient with skeletal Class III treated by
mandibular setback, BSSO by Dr Yatish Joshi et al in MIDSR
Treatment…
78. FUTURE INNOVATIONS IN
TREATMENT OF CLASS III
1. Distraction osteogenesis to advance the maxilla
78
Textbook of orthodontics by Dr. Samir Bishara
Treatment…
79. 2. Dental onplants to provide absolute maxillary anchorage
79
Textbook of orthodontics by Dr. Samir Bishara
Treatment…
80. REFERENCES
Textbook of orthodontics by Dr. Samir Bishara
Handbook of orthodontics by Robert Moyers; 4th edition
Contemporary orthodontics by William Profitt ; 5th edition
Dentofacial orthopaedics with functional appliances by
Graber and Petrovic
Removable orthodontic appliances by Graber and Neuman;
2nd Edition
Ariel Reyes et al, Diagnosis and treatment of Pseudo Class
III Malocclusion, Hindawi Publishing Corporation vol 2014
80
81. 81
Oommen Nainan et al, Evaluation of Malocclusion pattern and
Dentofacial characterstics in orthodontically referred urban Indians,
J Ind Orthod Soc 2013;47(4):328-34
Renato et al, Management of class III malocclusion treated with
maxillary expansion and facemask therapy: A 15 year follow up, J Appl
Oral Sci 2015;23(1):101-9
Hyung-Jun Choi et al, Cephalometric Characteristics of Korean
Children with Class III Malocclusion in the Deciduous Dentition, Angle
Orthod 2010;80:86–90
Shendre Shrikant et al, Correlation of the Anteroposterior
Relationships of the Dental Arch and Jaw-Base in subjects with Class
I, Class II and Class III Malocclusions. Int J Contemporary Dentistry,
March 2011;2(2)
82. 82
Pravin Kumar S Marure et al, Effective maxillary protraction with
Tandem Traction Bow Appliance, J Ind Ortho Soc 2014;48(3):198-205
Leon Klempner, Early Treatment of Skeletal Class III Open Bite with
the Tandem Appliance JCO June 2011
Marcio Rodrigues de ALMEIDA et al, Early treatment of Class III
malocclusion: 10-year clinical follow-up, J Appl Oral Sci 2011;19(4):431-9
Paula Vanessa Pedron Oltramari-Navarro et al, Early Treatment Protocol
for Skeletal Class III Malocclusion, Brazilian Dental Journal 2013;24(2):
167-173
Class III – small proportion of all, about 5% of all , more in Asian population
Class III – wen the mesiobuccal cusp of maxillary first molar occludes interdental space between the distal aspect of distal cusps of mandi 1st molar and mesial aspect of mesial cusps of mandi 2nd molar
Molar and canine relation are often not fully class I ii or iii, but rather intermediate relationships
Therefore, molar and canine that fall between class I and ii are end to end malocclusions
Between class I and class iii are super I malocclusions(notation SI)
Type 1 arches wen viewed have normal alignment but wen made to occlude show edge to edge relation
Type 2 mandi incisors are crowded and in lingual relation to maxi incisors
Type 3 maxillary incisors are crowded and are in crossbite in relation to mandi incisors
For neuromuscular or functional occlusion Moyer emphasized the need to determine whether it is in centric relation or convenient anterior position
Anterior positioning results from tooth contacts which force mandi in forward position
In contrast CR is determined by muscles, ligaments, TMJ anatomy under the CNS
A. Mandi Prognathism b.Maxillary retrusion c.Both normal d.Retrusion and protrusion
Higher in asians coz large number of patients show maxillary deficiency
The Asian patients with Class III malocclusion typically had a more retrusive facial profile and a longer lower anterior facial height. A backward rotation of the mandible was often observed to accommodate the relatively smaller maxilla.
Severe class iii are often associated with either anterior or posterior crossbites becoz either maxilla is placed too far back or mandible is too far forward
Presence of occlusal pre maturities resulting in habitual forward positioning of the mandible
Diagnosis is study and interpretation of data concerning a clinical problem in order to determine the presence or absence of abnormality.
The primary goal of these parameters is to help clinician distinguish between a case that requires limited ortho tt vs one that requires comprehensive ortho tt
Extraoral – frontal view at rest, frontal view smiling, profile view at rest to asses pt profile, facial asymmetries and smile line
Intraoral – frontal view, right and left lateral view and maxi and mandi occlusal view to provide general overview of malocclusion, gingival condition, and hypoplastic teeth
a. Pts with maxillary deficiency usually have a concave profile, evidenced by flattening of the infraorbital rim and area adjacent to nose
By blocking upper and lower lip, Evaluate chin position with reference to nose, upper face, and forehead
A degree of chin prominence that wud be normal for adult may suggest a class III skeletal profile in a young child
Evaluate midface by blocking out lower lip and chin
There should be a convexity to imaginary line normally
To asses angles classification of molar and canines, overjet and overbite, the approx. amount of crowding or spacing in a dental arch, presence of anterior or posterior crossbite
Bcoz model are 3 dimensional representation of pts dentition, they may b used to demonstrate malocclusion to both parent and patient
PANTOMOGRAPH-To assess the stage of dental eruption, missing supernumerary or impacted teeth, ectopically erupting teeth, and pathologic condition
LATERAL CEPHALOMETRIC- 1.to evaluate the relationship of the jaws and teeth,
2. diagnosis, tt planning, pretreatment, tt process and tt result and stability
Lateral cephalograms and study models of 276 untreated adult orthodontic patients representing Angles Class I, Angles Class II and Angles Class III malocclusions were taken. ANB angle and Wits appraisal were measured on the radiographs which were indicative of the skeletal relationship.
ANB ANGLE -The measured values in group I and group II indicated a Class II skeletal base. In group III the mean value showed a Class III skeletal base. However, the increase of ANB angle in group II was more than in group I
WITS APPRAISAL -In group I, mean value of Wits appraisal showed a mild Class II skeletal base. Group II showed a moderate to severe Class II skeletal base. In group III the mean value of Wits appraisal showed a Class III skeletal base
Wits appraisal decreases as ANB angle decreased
Soft tissue convexity (G-Sn-Pog) was significantly greater in the normal occlusion group.
While the lower lip position (lower lip to E-plane) was similar,
there was a significant difference in the upper lip position (upper lip to E-plane)
Pseudo Class III malocclusion is an intermediate form between Class I and skeletal Class III malocclusion.
The only exception was the gonial angle, which was generally more obtuse in the skeletal Class III sample.
Measurement of the gonial angle in the pseudo Class III sample was rather similar to the Class I sample, making this measurement a key diagnostic feature in the differential diagnosis
ANB angle is negative with smaller than normal SNA or greater than normal SNB
Also wits appraisal can be used
Pseudo class III – KEY DIAGNOSTIC FEATURE IS GONIAL ANGLE FOR DIFFERENTIATING
The mandibular articulation is more anteriorly posi- tioned, resulting in a more prominent lower law
The mandibular prominence along with the decreased length of the maxillary complex may accentuate the typical straight to concave profile in these cases. Typically, patients with Class III malocclusions display dentoalveolar compensation in the form of proclination of the maxillary incisors accompanied with retroclination of the mandibular incisors.
Similar mandibular growth increments between Class III and Class I patients during prepubertal, pubertal and postpubertal growth periods
Battagel41 found that the largest increment of facial growth for males occurred between the ages of 14 and 16 years, whereas in female patients the maximum increment of facial growth occurred between the ages of 9.5 to 12 years, although active growth continued in the nasal area and both jaws after the age of 15 years
Patients with pseudo Class III malocclusion often present with anterior crossbites that are caused by a premature tooth contact or improper positioning of the
maxillary and mandibular incisors and the temporomandibular joint.
Reverse stainless steel crowns were also used earlier
Reverse stainless steel crowns were also used earlier but were unaesthetic
of incisors, which might lead to gingival recession
(2) improving skeletal discrepancies and providing a more favorable environment for future growth;
(4) simplifying phase II comprehensive treatment and minimizing the need for orthognathic surgery
The author recommends that early treatment should be considered - positive column.
negative column - treatment can be delayed until growth is completed. Patients should be aware of the fact that surgery may be necessary at a later date, even when an initial phase of treatment may be successful.
Take advantage of natural forces and transmit them to skeletal areas to produce desired change
Force is functional and intermittent in nature
. Force application
Complementary muscular or mechanical force application of muscular or mechanical origin
2. Force elimination
Elimination of abnormal or restrictive environmental influences on dentition
Teeth respond to reduced force by setting up new balance
Unlike activator for class II, in class III activator the restraining effect is directed toward the mandible instead of maxilla.
Construction bite is taken in most retruded hinge axis position
Addition Mandibular labial bow added to guide incisors distally
Maxillary labial bow kept at some distance frm incisors to relieve lip pressure
Mandi plate and the two lateral maxi parts extending from 1st premolars to 1st premolars joined together opening the bite just enough to allow labial movement of maxi anteriors just past mandi anteriors.
Bite opening is not more than 2mm between the incisal edges
1mm thickness of acrylic is removed from behind the mandi anteriors
functional appliance designed to counteract the muscle forces acting on the maxillary complex.
According to Franke1, the vestibular shields in the depths of the sulcus are placed away from the alveolar buccal plates of the maxilla to stretch the periosteum and allow for forward development of the maxilla.
The shields are fitted closely to the alveolar process of the mandible to hold or redirect growth posteriorly.
The effectiveness of each appliance is dependent on patient cooperation and wearing them full time.
Adjustable wire with hooks connected to midline framework for protraction using ELASTICS
The design of anchorage system for maxillary protraction varies from palatal arches to rapid maxillary expansion (RME)
Most of the orthopedic changes are observed within the first 3 to 6 months after maxillary expansion.
Prolonged use of protraction force results in dentoalveolar changes including mesial movement of maxillary molars and proclination of maxillary incisors.
Maxillary protraction below the center of resistance produces anticlockwise rotation of the maxilla.
COR – distal to maxillary first molar halfway between functional occlusal plane and lower border of orbit
A 7.6-year old boy presented with Class III malocclusion associated with anterior crossbite; the mandible was shifted to the right and the maxilla had a transversal deficiency. The patient was followed for a 15-year period, after completion of the treatment, and stability was observed
The facemask was used 20 hours a day, for 10 months, after which the patient was requested to use it only at night, and use the acrylic appliance with a palatine grid 24 hours a day. Six months later, a satisfactory relationship in the anteroposterior plane and a mild improvement in the vertical one were observed.
Provide growth inhibition or redirection and posterior positioning of mandible
Occipital pull – for patients with mandibular protrusion
Vertical pull – for pts with steep mandi plane angle and excessive lower facial height
Graber study – Also The length of the mandible also decreased about 1 mm due to the pressure transmitted by the chincup to the condyle, which generated, on the other hand, a delay in vertical growth
Eschler modified labial bow to improve intermaxillary effectiveness. One part is active, moving the teeth and other is passive, holding the soft tissue of lower lip away and thus enhancing tooth movement
If necessary, springs and an expansion screw can be added
AIM - Angle Class III malocclusion, treated according to a two- stage approach (interceptive and corrective), and a long-term follow-up period.
Case - presence of this malocclusion in other family members was reported, lack of development of the middle third, forward shift of the mandible, functional Class III malocclusion.
a chincup was used only at night to maintain mandibular retrusion, and the eschler appliance, “progenic appliance”, was used during the day.
During the development of the occlusion, the patient was concerned about the gradual increase of the diastema between the central incisors. However, this condition was expected, since the growing mandible caused the proclination of the incisors, thereby increasing arch length
Approximately 2 years after the interceptive phase, and due to the patient’s dissatisfaction with the diastema, the second phase of this protocol was initiated with the installation of a fixed appliance
Lasted
Modified by Klempner in 2003
Masking the defect
Surgical technique- surgical exposure, osteotomy cuts, pterygomaxillary disjunction
Mobilization and advancement
Fixation
Bone grafting
An incomplete osteotomy placed above the canine and molar roots was performed through a vestibular incision. Pterygomaxillary disjunction and dissection of the nasal floor and septum were not per- formed. Distraction forces were placed on the maxilla by a reverse-pull headgear and an intraoral orthopedic appliance to advance the maxilla 8 to 12 mm.
One of the limitations in maxillary protraction with tooth-borne anchorage devices such as expansion appliances and palatal arches is the loss of dental anchorage (i.e., compensatory dental changes), especially with prolonged maxillary protraction.
undesirable effects -loss of arch length, forward movement of maxillary molars, and proclination of the maxillary incisors. These dental changes can be minimized or even eliminated with the use of a novel device called maxillary onplants.
The onplant comes as a disk, textured and coated with hydroxyapatite on one side and with an internal thread on the other side.
The onplant can be placed on the palatal bone. After osseointegration is complete, forces can be applied to the teeth from the onplant palatal anchorage.
apart from providing a stationary orthopedic anchorage, this device can be used in patients with multiple missing teeth