Ortho Pedo: Recent Episodes
Dr.Mayakha Mariam
BONE FORMATION / OSSIFICATION :-
INTRAMEMBRANEOUS- within membrane
Ossification takes place in the membranes of connective tissue.
Cells in the membrane differentiate into osteoblasts,
A collagen matrix is formed, which undergoes ossification
So basically, these bone is formed from collagen matrix.
Mostly flat Bones: maxilla, majority of mandible & cranial vault*
ENDOCHONDRAL – within cartilage
Bone formation takes place From within a hyaline cartilage
Cartilage cells are replaced by bone cells,ie. osteocytes replace chondrocytes.
short and long bones are formed this way
ethmoid, sphenoid, occipital (synchondrosis of bones of cranial base*)
Some part of mandible (condylar head region)
MANDIBLE BONE FORMATION IS BY BOTH endochondral + intramembraneous
BONE GROWTH
Don’t confuse bone growth with bone formation above
Growth of bone is by apposition — layer by layer deposition
Whereas cartilage growth is by two ways one is appositional and other is interstitial method, which is how mandibular condyle grows.
Mandible growth starts at 6th wk of IUL & completes at 12-13 years
Individual — 1st bone to ossify — clavicle— entire body
1st bone to ossify in head — mandible -2nd bone to ossify overall
Maxilla growth starts after mandible but completes earlier than mandible
Start (6th wk of IUL)----- (MANDIBLE) --------------finish (12-13 years)
-----------------START -------------------FINISH-------------------------
-------------------------------MAXILLA-----------------------------------
MANDIBLE
Primary cartilage of mandible — Meckel’s cartilage
but it does not individually induce or contribute to
mandibles growth
Secondary cartilage — condylar cartilage
This cartilage contributes to its growth*
Direction of growth — anterior and inferiorly
Direction of apposition @ condylar — posteriorly and superiorly
V shape principle- is shown by the mandibular growth
MAXILLA
Formed entirely by intramembranous ossification
Growth is by apposition at sutures and surface remodelling
Direction of growth/migration – downward and forward
Direction of apposition – downward at alveolar area and at tuberosity area
MAXILLA IN A NUTSHELL:
o Increases in height by continuous growth at alveolar bone
o Increases in width by mid-palatine suture
o Increases in depth by apposition at anterior region and tuberosity
SCAMMON’S GROWTH CURVE — GROWTH SPURTS
4 GROWTH SPURTS
1. JUST BEFORE OR AT BIRTH - Most rapid growth in human occur during pre-natal period
2. 1 YEAR AFTER BIRTH
3. PRE-PUBERTAL [GIRLS 5-6YEARS., BOYS 6-8 YEARS]
4. PUBERTY [GIRLS 10-12, BOYS 12-14]
Mandibular growth coincides with 4th growth sprout ie; pubertal
growth
A. Neural — Brain
a. At birth 50%
b. At 4-6 years — 95%
c. So below this age, ie around 3 yrs child will not be able to differentiate colours, tell his name and so.
d. Complete at 15 years age — 100%
B. Genital
a. Begins at 12 years
b. Complete at 18 years
C. Lymphoid / immunity
a. At peak — 200% — 12 years
b. Complete — 100% — 18 years
∴ immunity is highest in children
BONE JOINTS
SYNOSTOSIS
Bone formed b/w two bone junction
SYNCHONDROSIS
Cartilage formed at the junction of two bones
Eg. Spheno-occipital synchondrosis
SYNDESMOSIS
Ligament formed at the junction of two bones
Eg: stylohyoid
PAIRED & UNPAIRED BONES
Total no. of bones in skull :-
At birth — 45 bones
Later — 22 bones *
Unpaired bones in skull :-
A. Frontal [FACE OF SUHAIRA EPPO VIDARUM MACHA?]
B. Occipital
C. Sphenoid
D. Ethmoid
E. Vomer
F. mandible
REST ALL ARE PAIRED
DEVELOPMENT OF OCCLUSION
GUM PADS
0-6 months of age
Anterior open bite
So such complaint of open mouth by mother at this age
o Rx — self correcting anomaly ! (SCA)
NATAL TOOTH – tooth present at birth
NEONATAL TOOTH — tooth formed within 15 –
30 days.
Most common — mandibular (anterior) central incisor
Syndrome — Rege fede syndrome
Inability to suck milk —
Nutritional deficiency
Lower part of tongue irritation.
ALVEOLAR RIDGE
Transverse grooves — it divides the gum pad into 10
segments for future eruption of the teeth.
CALCIFICATION DATES
1st calcification seen at 14 weeks of IUL, max sinus develops
12th week – mandible
6-10weeks- palate
4-6 weeks- lip
In pedo root formation completes 1year after eruption
As a general rule,
o four teeth erupt for every six months of life,
o mandibular teeth erupt before maxillary teeth,
o teeth erupt sooner in females than males.
o During primary dentition, the tooth buds of permanent teeth develop below the primary
teeth, close to the palate or tongue. Tooth bud is always — lingual / palatal and inferiorly
placed.
PEDO TEETH
Smallest — mandibular L1
First erupting — mandibular C1
Largest tooth — mandibular 2nd M
PERMANENT TEETH
Smallest — mandibular CI
Largest — maxillary 1st M
First erupting — mandibular CI
SPACES
In primary teeth — physiologic space
It is self correcting anomaly
Midline Diastema
Maxillary 1.7mm — mesial to C
Mandibular 1.5mm — distal to C
They are known as Primate space or Anthropoid space or Simmian space.
SELF CORRECTING ANOMALIES
o Anterior deep bite — 6 months age anomaly
o (SCA) — Self correcting as posterior teeth erupts
o (self – correcting anomaly)
DECIDUOUS OCCLUSIONS :- PRIMARY 2ND MOLARS
FLUSH TERMINAL PLANE (SCA)
Most Commonly seen occlusion*
Straight line occlusion
EDGE TO EDGE OR END ON
Crowded , Improper jaw growth
CLASS I OCCLUSION
Mesiobuccal cusp of maxillary 1st M in the mandibular mesiobuccal groove
Usually a flush terminal will end up in class 1 itself
Self – correcting anomaly
MESIAL STEP OCCLUSION
Ideal Occlusion
CLASS III – When space is utilized
CLASS I – If space not utilized
DISTAL STEP OCCLUSION
CLASS I – If space is utilized
CLASS II- if space is not utilized
MIXED DENTITION :-
o Started #6 eruption of mandibular 1st Molars
o Finishes #3 eruption of maxillary C or #5 eruption of mandibular 2nd PM
PERMANENT SEQUENCE OF ERUPTION
MAXILLA
6 1 2 4 5 3 7
MANDIBLE
6 1 2 3 4 5 7
1st permanent tooth — mandibular 1st M
1st successor tooth — mandibular CI
Last successor tooth — max C *** OR mandibular 2nd PM
STAGES OF MIXED DENTITION :-
FIRST TRANSITION STAGE [ 6 – 8 ]
Erupting — C1, L1, 1st Molars
Anomaly — anterior open bite
o — retrognathic mandible (12-14)
o — ∴ transient class 2
At 8.5yrs old, there will be equal no of primary and permanent teeth in the mouth,
Centrals, laterals and 1st molars-permanent
Canines, 1st molar, 2nd molar-primary
Incisal Liability
o Maxilla — 7mm
o Mandible — 5mm
∴ avg I L = 6 mm
How is I L Obtained:
o utilising the physiologic spaces
o proclination of anterior
o increase in the inter – canine width
INTER – TRANSITION STAGE [ 9 – 11 ]
Anomaly — ugly duckiling stage (9 – 11 years) *** v.imp
o — midline diastema (SCA)
Erupting — canines
Distoangular axial inclination of maxillary incisors!
Rx – wait till canines erupt completely – 11 years
After that — ortho Rx.
SECOND TRANSITION STAGE
Erupting — C, 1st PM and 2nd PM
3, 4, 5, 7
Anomaly — anterior deep bite
LEEWAY SPACE — primary Molars > permanent Molars
it is the space deference between the combined mesiodistal width of the C,D & E teeth and that of their successors ( 3 ,4 and 5 ) which is
1.9 mm in maxilla & 3.4 mm in mandible.
— This space is utilized for primary occlusion to
permanent occlusion
— late mesial shift
o Maxilla — 0.9 mm
o Mandible — 1.7 mm
NON – SELF CORRECTING ANOMALIES :-
SKELETAL
1. Skeletal Class III
2. Skeletal class II
MIDLINE DIASTEMA * after 11 years or C eruption
a] Hgh frenal attachment
Blanch test — to detect high frenum attachement
Frenectomy
Wait for eruption of remaining teeth
Ortho
b] unerupted mesiodense
Rx
o Occlusal radiograph
o If before C eruption — extraction of mesiodens might close the gap as C
erupts completely
o If after C eruption — extraction of mesiodens + fixed ortho
CROSSBITE
a. 1st seen at 7 – 8 years
b. ∴ 1st ortho visits @ 7 – 8 years
c. 1st dental visit @ 6 months
d. 𝑎𝑛𝑦 𝑚𝑎𝑙𝑜𝑐𝑐𝑙𝑢𝑠𝑖𝑜𝑛 — due to early lossof primary teeth
e. 𝑎𝑛𝑡𝑒𝑟𝑖𝑜𝑟 𝑐𝑟𝑜𝑠𝑠𝑏𝑖𝑡𝑒 — retained primary teeth
ANTERIOR CROSSBITE
DEVELOPING Rx – icecream stick pushes
DEVELOPED Rx – orthodontic
1) Catalans appliance
a. 6 weeks
b. Lower teeth
c. 45° angulation
d. If Catalans appliance used more than 6 weeks
e. Then — separation of occlusion in posterior
2) Z – Spring with posterior bite plane
a. For developed crossbite
2) Z – Spring with posterior bite plane
a. For developed crossbite
POSTERIOR CROSSBITE
Reasons — narrow maxillary jaw
Rx plan
o Expansion of maxillary arch
o Maxillary expansion device
o At or above 7 years of age
o Max suture growth ends at 15 years
o Both unilateral and bilateral posterior crossbite
Function of expansion device —bilateral expansion
Effect seen when midline diastema appears
This diastema closes as a result of relapse
No Rx required for midline diastema
UNILATERAL CROSSBITE
1. LAERTOGNATHY / TRUE CROSSBITE
The center of the mandible and the facial midline does not coincide in both rest and in occlusion
2. LATEROCCLUSION
The center of the mandible and the facial midline coincide in rest position butttt in occlusion the
MAXILLARY EXPANSION DEVICE
RAPID MAXILLARY EXPANSION (RME)
a) Per day 0.5 mm
b) Key turn/ activation :-
- ¼ turn twice daily or
- Quarter turn twice daily or,
- 0.25 mm twice daily
c) Eg: Hyrax
- Ratio =𝑑𝑒𝑛𝑡𝑎𝑙/𝑏𝑜𝑛𝑒= 1: 1
- The ratio of dental & skeletal expansion obtained after RME is 1 : 1
SLOW MAXILLARY EXPANSION (SME)
a) 0.5 mm per week*
b) eg: quad helix
c) unwind the coil(no key system)
HABITS
THUMB/DIGIT SUCKING, PACIFIER
Normal upto 3 years according to
— Psychosexual theory
— Learning theory
— Oral drive theory
— Routine reflex theory
— These theories support that up to 3 years its normal
Side effects if continued after 3 years
- Increased overjet – owing to Maxillary anterior teeth proclination & Retruded and crowded mandibular incisors
- Posterior crossbite (due to action of buccinator muscle During the sucking action – buccinator mechanism)
- Anterior open bite, flaring max incisors
- Anteriorly displaced maxilla, Retruded mandible
- ie. Class II occlusion
- Dish pan thumb
- Deep palatal vault
Treatment phase
- Counselling phase (all age group)
- If dental damage not happened, Pychological treatment to withdraw from habit
- But- if already dental dame caused- Definitive management
Definitive management
1. 4 – 5 years age —1st phase : reward therapy
2. 5-6 years age and above : 2nd phase : reminder therapy
Tongue crib
- Fixed
- Removable
Blue grass appliance(also given in tongue thrusting)
- Fixed appliance with six sided plastic roller on the anterior surface of
palate region.
3. 3rd phase : corrective therapy
Quad helix — habit breaker + arch expansion
(Dip finger — pepper solvent, asefoitida solvent - it is an adjacent therapy)
TONGUE THRUSTING
Proclination of anterior both maxillary and mandibular
Rx
- Tongue crib / blue grass appliance – must be used as soon as the habit is noticed
- Atleast 6 months (Rx) + 3 months (retention purpose)
- Total about 9 – 10 months
‘Duration of habit force — determines the degree of malocclusion’
– not the frequency
MOUTH BREATHING
Reasons:
- Obstructive problem
Eg: adenoids
Rx: refer to ENT surgeon for removal of adenoids
- Habitual problem
Patients who show this habit even after surgical correction, this is habitual now, ie despite no obstruction now, they are breathing due to th habit they developed before.
Rx : oral screen / mouth screen (only in cases no obstructive causes or
H/O removal of cause)
Clinical features
Anterior proclination
Incompetent lip seal
LEPTOPROSOPIC
Long face syndrome
They have posterior cross bite
Said to have a classic adenoid face
Poor lip seal
Tests used for investigation of mouth breathing
Mirror test *
Butterfly test
Waterbath test
MODEL ANALYSIS
Why – to determine the arch length and tooth material discrepancy
o If the discrepancy less than 2.5 mm - proximal stripping prior to ortho
o If the discrepancy more than 2.5mm – 5 mm - extraction of 2nd PM, usually after starting ortho
o If the discrepancy more than 5 mm – 10 mm - extraction of 1st PM
Proximal stripping remove only 50% enamel, otherwise there will be severe sensitivity.
Normal occlusion — Andrew’s six keys
7th key added — Bolton ratio = 91.3%
MIXED DENTITION ANALYSIS
WHY — to predict the crowding of maxillary or mandibular arch
Determines the space available vs the space required
It is the best investigatory method for serial extarcation
HOW (Moyer’s analysis) —𝒔𝒖𝒎 𝒐𝒇 𝒎𝒂𝒏𝒅𝒊𝒃𝒖𝒍𝒂𝒓 𝒊𝒏𝒄𝒊𝒐𝒓 𝒘𝒊𝒅𝒕𝒉 (𝒄𝒊+𝒍𝒊) / 𝟐
The size of unerupted permanent canines and PMs are predicted from the knowledge of
the size of M-D width of mand incisors.
Mxillary incisors are never measeared coz of high chance of variability. Mandibular is taken even to predict maxillary space discrepancy.
Best analysis done = Stanley kaber analysis
Tooth cause crowding in lower anterior region if early extracted: Primary mandibular first molar lower ie. D
Most teeth responsible for crowding is: Lower E & upper D
SERIAL EXTRACTION:-
C D 4 — order * if discrepancy > 10mm
Preferred — Dewel procedure
Done at 8-9 years only if there is crowding!
Anything before that extract ad give space maintainer.
Go for double extraction if age 8-9 and crowding not present
Advantages :
o Interceptive orthodontics
Easy ortho movement in future due to breakage of transseptal fibres — no relapse
o Helps eruption of permanent canine ?
SPACE MAINTAINERS:-
Function — to maintain space
Space closure is least likely to occur in primary maxillary 2nd molar
Anterior SM function —
o To maintain phonetics
o Aesthetics
o Space maintenance
Fixed SP is better
Removable space maintainer used when SM required at multiple location
Eg: RPD
BAND & LOOP SM
Single tooth missing
Both maxillary and mandibular
Missing D (at any age)
Missing E at or above 6 years when 6 tooth available
CROWN & LOOP SM
If abutment tooth has pulpectomy or large caries
Both maxillary and mandibular
DISTAL SHOE SM
If E is missing both maxillary and mandibular
Age group of 5 years or below
Shoe into the extraction socket of E
Contra – indicated in bleeding disorders and infective endocarditis
MAX – TRANSPALATAL SM
Unilateral loss of E&D * in maxillary only
Connect 6 of opposite arches *at or above 6 years old
Acts as space maintainer + arch expansion + anchorage — function of TPA SM
NANCE PALATAL ARCH (NPA)
Can use for both unilateral and bilateral
o E missing and D missing
Only in maxillary
At or above 6 years age’support from palate – not teeth
LINGUAL ARCH
Above 7 years
Because support from anterior teeth
Both unilateral and bilateral and multiple missing
Anterior Space maintainer
REMOVABLE DENTURE, with adams / c clasp / ball clasp
RPD is advisable only if child is 3yrs above
FIXED SPACE MAINTAINER, orthodontic bands on primary 2nd molars
Wire extents anteriorly on the ridge and teeth are fixed on to the wire.
Mostly for children less than 3yrs, to compensate for speech improvements
PS: If teeth will erupt in 6 months, ---- No need of space maintainer!
CANINE EXFOLIATION
Mandibular – 9 years
Maxillary – 11 years
If unilateral extraction required then intentionally extract other C also — to prevent
midline shift — in mandibular only — at 9 years
Maxillary causes — only extract diseases and give space maintainer — 9 – 10 years
PREMATURE EXFOLIATION OF C
After effects seen
Lingual collapse of mandibular anterior
Midline deviation of mandibular
anterior towards C
Increased overbite
Loss of arch length or its deficiency
Increased overjet
Max canine is most impacted
Embedded teeth due to lack of eruptive force,
While impacted teeth is due to lack of space.
MALOCCLUSION IN PERMANENT DENTITION
CLASS I
The buccal groove of mandibular 1st permanent molar must occlude with the mesiobuccal cusp of maxillary 1st molar
CLASS II div I
Buccal groove of mandibular molar occludes posterior to the mesiobuccal cusp of maxillary 1st molar
CLASS II div I
Maxillary anterior proclination
Cause — growth discrepancy
Soft tissue protrusion in: Class II mod I.
CLASS II div 2
Maxillary anterior proclined, where laterals proclined and C I’s retroclined
Cause — growth discrepancy
TRUE CLASS III
Buccal groove of mandibular molar occludes anterior to the mesiobuccal cusp of maxillary 1st molar
Skeletal malocclusion
Cause – hereditary
PSEUDO CLASS III
Habitual
CANINE RELATIONSHIP
The canine relationship can be used as another method of classifying the AP occlusal relationship.
The classification is outlined below:
Class I – the maxillary permanent canine occludes in the embrasure between the lower canine and 1st premolar
Class II – the maxillary canine occludes anterior to the embrasure between the lower canine and 1st premolar.
Class III – the maxillary canine occludes posterior to the embrasure between the lower canine and 1st premolar
ORTHODONTIC TOOTH MOVEMENT:
According to force
o Light continuous force
o Heavy continuous force
o Heavy Interrupted force
Direction
o Tipping
o Intrusion
o Extrusion
o Bodily movement
o Torque
o Coupled form
LIGHT CONTINUOUS – ORTHODONTIC* ORCE:-
Frontal resorption is the result
Osteoclasts and osteoblasts DEPOSITION + RESORPTION
PDL is compressed at resorption side
PDL is tensed at deposition zone
HEAVY INTERUPTED – ORTHOPEDIC* FORCE
Hyalinization & undermined resorption is the result here
In head gear cases – its principle
Light continuous is acceptable, so is heavy interrupted, but heavy continuous should be avoided.
Headgear appliance used for anchorage & traction.
Chin cup apply to class 3 with long lower face.
Levering the curve of spee for correct deep bite.
Minimal Space needed between primary and permanent dentition
IS : 6 mm in mandible and 7 mm in maxilla.
ORTHO MOVEMENT DEPENDS ON THE MAGNITUDE OF THE ORTHODONTIC FORCE*
TIPPING
Force — 20 – 50 gram force
Most commonly used in ortho Rx
Removable appliance
Centre of rotation at apex
Root apex at same point and
Controlled tipping
BODILY MOVEMENT/ TRANSLATION
Moves the tooth entirely from one position to another.
Single force is applied at the center of resistence (varies from tooth to tooth)
Possible only with fixed ortho appliances
Not possible with removable appliances
INTRUSION
Minimal force
Very difficult to attain this movement
Only resorption, no deposition
Contra – indicated in gingivitis
Causes : periodontitis
TORQUE
Opposite of tipping
Change in Labiolingual /axial inclination of tooth
EXTRUSION
Only bone deposition
Very simple to attain
Mostly done to create Ferule effect*-orthodontic extrusion
The fibers that prevent extrusion and lateral tooth movement is the alveolar crestal fibers.
COUPLED FORCE
Correction of rotation
Two equal parallel forces acting in opposite direction
Retention of PMs.
Transpalatal fibres may need to be cut, - PERICISION is usually indicated after correction of rotation – also call it as CIRCUMFERENCIAL FIBROTOMY
FINISHING MOVEMENTS
Wires used here — beta titanium wires*
Torqueing & uprighting
LABIOLINGUAL MOVEMENT OF ROOT * CORRECTION OF MESIODISTAL ANGULATION
CROWN IS STABLE HERE
Centre of rotation at bracket bonded region on crown
TYPES OF BONES
A) WOVEN BONE* – 1st bone formed in response to orthodontic loading force. It is weak, disorganized, poorly mineralized. It si compacted later to form the COMPOSITE bone, then remodelled to form LAMELLAR bone, if not rapidly resorbed if too much load is given.
B) LAMELLAR BONE - Strong, highly organised well-mineralized tissue
C) BUNDLE BONE - PDL
ANCHORAGE
STATIONARY ANCHORAGE
I. Class I
a. Intra arch / class I elastic
b. Canine to Molar cases (to close extraction space)
c. They are called buccal canine retractors.
II. Class II and c) Class III
a. Inter – arch elastics or Baker’s anchorage
b. Or class II/III elastic anchorage
c. Upper to lower jaw
d. Class II upper C to lower M
e. Class III upper M to lower C
RECIPROCRAL ANCHORAGE
a) Equal and opposite movement
b) Midline diastema cases closure
c) Posterior crossbite — RME principle
NB: When placing orthodontic bands, theoretically, it is said that we
need prophylactic antibiotic coverage, this is also to prevent
subacte bacterial endocarditis (omr)
CONTRA INDICATIONS FOR ORTHO:-
- Gingivitis, periodontitis, poor oral hygiene
- NSAID taking patients
a. Because its anti-inflammatory, but ortho needs inflammation action for osteoclasts and osteoblasts. Eg: ibuprofen, aceclofenac, meftal, paracetamol etc - Females above years (menopause)
a. Chances of osteoporosis for which bisphosphonates (same contraindicated in IMPLANT) are given — no resorption action - Marfans Syndrome
a. Abraham Lincoln
b. Spider web fingers and toes
SKELETAL ABNORMALITIES MYOFUNCTIONAL APPLIANCES:- IF SEEN BELOW 18 YEARS
Skeletal class II
o Class II retrognathic mandible
o Myofunctional appliance best given in late mixed dentition period to promote
mandible, (not maxilla)
o FRANKEL APPLIANCE 2
Passive type myofunctional appliance
Mandibular affect
Cause mandibular prognathism
o ACTIVATOR
Common myofunctional appliance
o LIP BUMPER
Semi-fixed appliance
Space regainer + myofunctional action
For molar distalisation.
o ORAL SCREEN
Habit breaker for mouth breathing + myofunctional
Q. Functional appliances: if asked about functional appliances in the exam just mention posterior bite block: D even if he said active functional: D and do not worry you will get the mark: D no idea how.
but let's explain some notes about functional appliances :
Tooth borne appliances: a) bionator B) herbest(pins and tube device) Tissue borne
appliances: Frankel is the only tissue borne functional appliance
NOTE: all below 18 years at late mixed dentition
12 YEARS AGE
Growth spurt is minimum, myofunctional wont work
So need faster acting appliance like
o Herbst — rigid , fixed
o JASPER JUMPER
Fixed but
Semi – rigid
o TWIN BLOCK
70° angulation
Removable , 12 hours per day
ORTHOPEDIC APPLIANCE
SKELETAL CLASS II - MAXILLA (PROGNATHIC)----headgears
HEAD GEARS : -
8 YEARS
High pull, normal pull, cervical pull
HIGH PULL
o Vertical growth pattern
o Corrects gummy smile
o Corrects overbite
CERVICAL PULL
o Horizontal growth pattern
o Increase lower facial growth by
Extrusion of molars
o Corrects deep bite
NORMAL PULL
o Normal growth pattern
Must wear 12-14 hours
The force applied here is intermittent (not heave, continuous, light,etc)
One side force = 450grams (300-500 gm)
Principle — hyalinization + undermined resorption — heavy force
Q. Active appliances employ force to the teeth to change their position -Most active appliances are fixed. Examples of active appliances include: Rapid maxillary expansion appliance (palatal expander)twice per day 0.5 – 1mm/ day) o Helix o Bite plate o Pin and tube o Ribbon arch o Edgewise o Beg light wire
SKELETAL CLASS III – PROGNATHIC MANDIBLE’
CHIN CUP
DAILY 12-14 HOURS
8 YEARS AGE
Force = 900 – 1000 grams
Backwards and superior force direction
SKELETAL CLASS III – RETROGNATHIC MAXILLA
Face mask / Face frame
Or reverse head gear
Daily 12 – 14 hours
Force 450 grams per side
Force direction – downwards and forward pull
18 YEARS AGE
ORTHOGNATHIC SURGERY
Only above 18years age
If done below 18 years — chances of growth
HIGHER FORCE (head gear)
Decreases blood supply — cell death
Avascular area — hyalinized area
No teeth movement — instead bone changes occur
ORTHOGNATHIC SURGERIES
a) Mandible retrognathism (CLASS II) — bilateral sagittal split osteotomy (BSSO)
b) Maxilla prognathism (CLASS II) — anterior segment osteotomy
c) Class III mandibular prognathic — BSSO set back
d) Maxillary retrognathic — le FORT I Osteotomy
BSSO
Take care of inferior alveolar nerve
Saggital plane
Bilateraly
For prognathism / retrognathism
QUAD ANGULAR LE FORTE 2 SURGERY
For midface deformity or deficiency
Q. Orthognathic surgery, you plan to use 2 mm screw the drill
size:1.5 mm.
ORTHO WIRES
NICKEL TITANIUM WIRE
Super elasticity
Shape memory —
Changes from austetic martentic (A M)
No plastic deformation
Disadvantage — high friction
If NITI wires fractures, it is because of axial fatigue / dynamic & cyclic fatigue.
𝜷 TITANIUM
Used when patient has allergy to nickel in
Highest friction
Finishing wires – ie. Used for making final tooth movements
Torqueing and uprighting
ROTARY NiTi FILES:-
Usable in curved canal
Can use only 3 teeth due to dynamic cyclic fatigue torsion — causing fracture
18 – 8 STAINLESS STEEL
18% chromium — passivation (function)
8% nickel
Very low friction
DIAGNOSTICS
Cephalometry