Ortho Flashcards
Purpose of study models
tx planning
pt motivators
secondary opinion
checking person’s occlusion
ortho design for removable appliance
Advantages of URA
tipping teeth
excellent anchorage
OH easier to maintain
cheaper than fixed
shoter chairside time
less specialised training to manage
easily adapted for ob reduction
achieve block movements
non destructive to tooth structure
Disadvatanges of URA
less precise control of tooth movement
easily removed by the patient
1-2teeth moved at one time
specialist staff to construct
rotations difficultt to correct
Active componenet
What actually moves the tooth
Retention
components that are resistant to displacement forces
Anchorage
resistance to unwanted tooth movement
Baseplate
self cured PMMA
connector, retention, anchorage
S.S wire composed of
iron - 72%
chromium - 18%
nickel - 8%
titanium - 1.7%
carbon - 0.3%
Fitting a URA
ensure pt details match details of appliance
check appliance matches design specification
run finger over fitting surface looking for sharp areas
check integrity of wirework
insert appliance and look for areas of blanching
check posterior retention - flyover then arrowheads
apply same principle to anterior retention
activate appliance
Patient info and instructions
appliance will feel big and bulky
may cause initial excessive salivation
may impinge on speech for short period
initial pain or discomfort
wear 24/7 including mealtimes
remove applaiance when participatating in contact sports
avoid hard and sticky foods
mention about non compliance and lengthening tx
provide emergency contact details
How does a flat anterior bite plane work?
it works to decrease the pt overbite
it increases the vertical dimension allowing overeruption of posteriors and raises bite
OJ + 3mm = so lowers don’t stop behind bite plane causing trauma and retroclining them
Flat posterior bite plane
will disengage the bite allowing teeth to move forward
Tubing and sheathing do for certain active componenets
gives componenets stability and rigidity
Types of ortho movement
tipping
extrusion
rotation
torque
bodily movement
intrusion
Andrews 6 keys
tight approximal contacts with no rotations
class1 incisors
class 1 molars
flat occlusal plane or slight curve of spee
long axis of teeth have slight mesial inclination
crowns of canines back to molars have lingual inclination
Useages of fixed appliances
correction of mold to moderate skeletal discrepancies
alignment of teeth
correct centrelines
OB and Oj reduction
closure or creating spaces
correction of rotations
vertical movements of teeth
Advantages of fixed appliances
moves multiple teeth
pt cannot remove the appliance
precise movement
not too bulkly and invasive
can rotate teeth
bodily move teeth through bone
Disadvatanges of fixed appliances
poor oh
soft tissue trauma
relapse
resoprtion
expensive
less anchorage
etch can damage teeth
needs specalist training to fit
When is relapse potention high
diastemas
ectopic canines
AOB
proclination of lower incisors
Problems with fixed appliances
decalcification around brackets
root resorption - mostly intrusion movements
teeth become non vital
trauma from headgear
Extra oral anchorage
headgear - head cap with intra oral bow attached to fixed or removable appliance
200-250g for 10-12hrs wear
Transpalatal Arch
0.9mm HSSW - attached to first molars
anchorage
rotation
Palatal arch with nance button
0.9mm HSSW attached to 1st molars
anchorage
(difficult to clean underneath and can lead to erythematous candidosis)
Quadhelix appliance
0.9mm HSSW
bilateral expansion
habit breaker
asymmetrical expansion
fan style expansion
rotation of molars
expansion in cleft palate
modified to procline incisors
Class 2 div 1
lower incisors lie posterior to the cingulum pleatu of the upper incisors
Increased overjet and upper centrals proclined or average
Why treat class 2 div 1
aesthetics
dental health - trauma from overjet
Skeletal pattern of class 2 div 1
class II anterior posterior pattern (retroganthic mandible, the mandible is further back
Soft tissues of class II div 1
incompotent lips due to prominence of incisors and underlying skeletal pattern
Dental factors of class 2 div 1
OJ - either crowding or spacing present
lack of spcae on uppers can exacerabte OJ
lack of space on lowers compensate OJ
Habits of class 2 div 1
sucking habits - proclinatin of upper incisors, retroclination of lower inciosrs, AOB, narrow upper arch and unilateral postirior crossbite
Erly treatment options for class 2 div 1
accept and await development (mouthguard for sports)
Growth modifcation - functional or headgear
URA to tip back upper incisors (mild only)
Treatment options for class 2 div 1 - class 1 or mild skeletal 2 pattern
accept
growth modifcation
camouflage
Class 2 div 1 - moderate to severe skeletal class 2 pattern
accept
growth modifcation
camouflage
surgery when growth complete
when is growth complete in females
16 years
when is growth complete in males
18 years
Headgear
restrain growth of maxially both horizontally and vertically using elastics - no change in lowers
Functinonal appliances
Restrain maxilla and encourage mandibular growth (twin block)
Tooth growth not growth modifcation - distal movement of upper dentition and retrocline of upper incisors, mesial movement of lower incisors and proclination of lower incisors
Camouflage
jaw pattern not changed but teeth move
Used for mild or moderate discrepancy
if used for severe can flatten face and poor appearance
Class 2 div 2
The lower incisor edges lie posterior to the cingulum plaetu of the upper incisors
upper centrals are retroclines
OJ minimal or can be increased
Skeletal pattern for class 2 div 2
mild to moderate skeletal class 2 A/P
promienent chin (progenia)
FMPA reduced and downward growthh of mandible
Soft tissues for class 2 div 2
<LAFH - lower lip higher in relation to crown of upper incisors and will retrocline the upper incisors (high lower lip line)
Dental features of class 2 div 2
retroclined centrals and upper 2’s being crowded due to incisors being retroclined
increased overbite
Traumatic occlusion
Ectopic canines sometimes
Why treat class 2 div 2
aethetics
dental health - traumatic overbite
Treatment options for class 2 div 2
accept
Attempt growth modification - functional appliance - convert from class 2 div 2 to class 2 div 1 to increase OJ for functioal appliance
Camouflage
Allign upper only - risk of relapse high and fixed retainer required
Orthognathic surgery - growth has to be complete and severe skeletal discrepanncy
Prognosis of class 2 div 2
difficult to treat due to facial growth
Deep bite and rotated laterals likely to relapse so retention is required
Benefits of ortho
improves function
improves appearance
inproves dental health
reduces risk of trauma
Risks of ortho
Declacificaiton
Relaspe
Root resorption
loss of tooth vitality
Loss of perio support
toothwear
soft tissue trauma
allergy
ulceration
Headgear trauma
Risk factors for root resorption
tooth movement - prolonged, high force, torque, large movements, intrusion
Previous trauma
Nail biting
Root form - blunt, pipette, resorbed already
Benefits of hawley retainer
removable so OH good
incorporates all teeth
strong
allows occlusal setting
minor tooth movement
Disadvantages of hawley retainer
removable so pt not complinant
speech issues
aethetics
expensive and time consuming to make
invasive on tongue space
Benefits of thermoplastic retainer
aesthetics
less invasive
cheap
all teeth incorporated
OH good
easier to make
slight tooth movement if needed
Disadvantages of thermoplastic retainer
non resilant
does not allow occlusal setting
compliance
easily lost
disorted with heat
Benefits of fixed bonded retatainer
compliance as fixed
aesthetics
non invasive
done chairside
cheap
Disadvatnages of fixed bonded retainer
does not incorpate all teeth
OH probs
etching damages teeth
easily fail adn debond
What are fixed bonded retainers good for
diastemas
rotations
Class 3 malocclusion
lower incisor edge occludes anterior to the cingulum plaetu of the uppers
OJ i reduced or reversed
Why do you treat class 3
aesthetics
function and speech
traumatic occlusion
TMD
ging recession
Class 3 skeletal features
anterior/posterior - occur in class 1, 2 or 3 skeletal base
vertical - increased FMPA and AOB
transverse - may be bilateral crossbites due to maxiallart deficinency, lowers may be more buccally placed than uppers
Class 3 soft tissues
natural attemps at compensation or camouflage
uppers proclined and lowers retroclined
tongue proclines uppers
lips retrocline lowers
Class 3 enviornmental factors
cleft lip and palate
acromegagly - disorder of pituarty gland so increased growth hormone causing enlargement in mandible
Early mixed dentition tx for class3
upper centrals develop palatally to A’s
if A fails to exfoliate can leave central behind lower incisors
premature contact on central incisors
Use URA to treat
Late mixed dentition tc for class 3
growth modifcation - functional (Frankel III or reverse twin block or protraction headgear with maxiallry expansion)
Early permanent dentition tx for class 3
camouflage - produce class 1 incisors - XLA lower 4’s and upper 5’s
Ortho and orthgnathic surgery for class 3
moderate to severe class 3 with severe vertical discrepancy
1) decompensate the incisors and make reverse OJ worse
2) UI/MxP = 104 degrees, LI/MnP = 90 degrees pre treatment
3) surgery to reposition jaws
4) post surgical ortho
Class I
maxialla 2-3mm in front of mandible
Class II
maxilla 3mm in front of mandible
Class III
mandible infront of maxilla
2 ways to assess the anterior positerior position
visually by pts profile and frankfort plane parallel to the floor
Palpation of skeletal bases
Frankfort plane
porion to orbitale
Mandibular plane
menton to gonion
Types of crowding
mild = 1-3mm
mod = 4-8mm
severe = >8mm
Overjet
horizontal distance between labial surface of upper incors and labial surface of lowers
average = 2-4mm
Overbite
vertical overlap of incisor teeth
Average = upper incisors overlap the incisal 1/3rd of crowns of lowers (50%)
Molar relationship class 1
mesiobuccal cusp of upper molar will occlude with buccal groove of lower 1st molar
Molar relationship Class II
mesiobuccal cusp of upper molar will occlude to the buccal groove of lower 1st molar
Molar relationship Class III
mesiobuccal cusp of upper molar will occlude posterior to buccal groove of 1st molar
Gonion
most poterior inferior point of angle of symphysis
Menton
lowest point on madibular symphsis
Nasion
most anteiror point on frontonasal suture
Orbitale
infeior anterior poart on margin of orbite
Porion
upper most outermost part of bony external meatus
Mandibular plane
line joining mention and gonion
Uses of lateral cephs
gross inspection of antomy and physiology
assess dentoskeletal relationships
soft tissue relationship to hard tissues
prognosis and tx planning
monitoring facial growth
Normal SNA
81 +/-3
Normal SNB
78+/-3
ANB
3+/-2
MMPA
27+/-4
FMPA
55+/-2
Ui/max
109+/-6
Li/max
93+/-6
Common supernumary teeth
anterior region in maxilla
males more common
Mesiodens
supernumary tooth between centrals
Syndromes with supernumary teeth
cleft lip and alveolus
celdicranial dysplasia
gardner syndrome
Conical tooth
peg shaped
erupt and XLA
Tuberculate
paired and barrel shaped
tend not to erupts
Suppplmental
extra tooth with normal morphology
Odontome
can prevent tooth eruption
XLA
Compound odontome
discreet denticles
Complex odontome
disorganised mass of dentine pulp in enamel
Causes of a supernumary
midline diastema
crowding
AOB
X bite
Problems with supernumary teeth
Poor aesthetics
impreded eruption
displaced eruption of adjacent teeth
Common hypodontia teeth
3rd molars
lower 2nd premolar
upper laterals
lower incisors
Females more common
Causes of hypodontia
environmental or genetics
trauma
down syndrome
cleft lip and palate
Ehler’s Danbs syndrome
Ectodermal dysplasia
Problems with hypodontia
Cleft lip and palate
malformation of other teeth
short root anamely
impaction
delayed eruption
crowding
enamel hypoplasia
altered cranifacial growth
spacing
infra occluded primary molar
drifitng
aethetics
fucntion issues
Management for hypodontia
spacing opening
space closure
accept
Concerns of retained primary tooth
retained primary teeth when difference of 6months between shedding in contra-lateral
How much space is required for 2 missing lower incisors
6mm each tooth
Tx of absent succesor
kept as long as possible
XLA early to encourage space closure
Tx of infra occluded primary molar
permanent tooth present - kept under review and XLA of contact going subging or root formaion on succesor 2/3rds
permanent tooth absent - depends on crowding, retained with onlay or XLA for space management
Causes of early loss of primary teeth
Caries
Trauma
severe crowding
premature exfoiation
Digit sucking causes
proclined upper incisors
retroclined lower incisors
AOB
Posterior cross bite
How is a posterior crossbite formed in digit sucking
the thumb goes in the mouth casues the mandible to dop down and tongue held in lower position
sucking action caused by cheeks narrows maxiallry dentition and posterior croos bite forms
Mangement of digit sucking
positive reinforcement
bitter nail varnish
socks on hands at night
habit breaker device (palatal crib)
tonge rake
elastoplasst on digit
Anterior cross bite managemtn
z spring with posterior bite plane
(if needs more than just tipping then fixed applaicnes afterwards)
Posterior cross bite maangemetn
URA or quadhelix to expand maxiallry arch
Casues of posterior cross bite
digit sucking
TMD
Ging reciession
crowding
cleft lip and palate
supernumerary
displacement on closure
tooth wear
mobility of lower incisors
retention of primary teeth
Causes of a diastema
midline supernumary
genetics
abnormal frenum
missing or small upper laterals
Mangement of diastmea
fixed applaince
palatal bonded retainer
when is the best time for extraction of 6’s
bifurcation of 7’s are forming, morec crucial on the lowers
too early = poor space closure
too late = distal drift of 5’s
Management of ectopic canines
XLA of c’s, retain 3 and observe
surgical exposure and ortho (gold chain if canine buccally placed)
autotransplantation
What 2 radiographs do you take for ectopic canines
OPT and occlusal
what to check for in ectopic canines
check at 9 years old
palpate to check bulge present
inclination of the 2’s
mobility and colour change of C or 2
Caues of ectopic canines
genetic and enviornment factors
long bath of eruption
displacement
demintitve lateral incisors
smaller maxillary arch
increased crowding
Problems with ectopic canines
cyst formation
root resoprtion
what can a labial frenum do
cause a midline diastema
what can tongue thrusting do
push incisors out
Causes of an AOB
Digit/thumb sucking
endogenous tongue thrust
supernumerary tooth present
delayed eruption
disabilties - cerbral palsy
How much of an AOB would you do orthognathic surgery
> 4mm
Indications for a functinoa lappliance
average or reduced FMPA
uncrowded arches
lower incisor upright
mild to moderate class II
How does a functiona appliance work
enhacnement of mandibular growth is brought about by movement of the mandibular condyle out of fossa prmoting growth of condylar cartilage and forward migration of glenoid fossa
Restrain of forward maxiallry growth
increase in lower face height
Advantages of a functional appliance
reduced overbite
corrects molar relationship
conrrect angulation of upper incisors
encourages favourable skeletal growth
Tipping movement
35-60 grams - URA can only carry out this one movement
Bodily movement
150-200 grams
movement of whole tooth
slide along wire
Intrusion
10-20grams
pressure evenly distributed on supporting structures which will cause required bone resorption
Too much force and will tear blood supply at apex
Extrusion movement
35-60 grams
tension induced along perio ligament producing bone despoition
Rotation movement
35-60 grams
Torque movemetn
50-100 grams
movement of root but tooth in same position
What are the factors affecting tooth movement
magnitiude of force
patients age
patients anatomy
the duration
Light forces on tooth
hyperamia within perio ligament
osteoclasts and osteoblasts appear
resorption of lamina dura
remodelling of socket (frontal resorption)
ging remains distorted and stored energy leads to relapse
Moderate forces on tooth
occlusion of blood vessels on side with pressure
tooth may be slighlty loose after movement
Excessvie forces on tooth
necrosis of tooth with undermining resorption present
resorption of root surfaces by osteoclasts
Syndrome
a group of anomalies that can be tied to a common origin - e.g - trisomy of 21 in down syndrome
agensia
absence of organ due to failed development during embryonic period
secondary abnormaility
interuptino of the normal development of an organ that can be traced back to other influences
(infections - rubella, trauama)
Primary abnormaility
defect int he structure of an organ or part of an organ which can be traced back to an anomaly in development
(spina bifida, congenitial heart defect)
Foetal alcohol syndrome
develops around day 17
small head
short palpbral fissures
short nose
long upper lip
deficient philitrum
flat midface
small mandible
Hemifacial Microsoma
multifactorial - potentially due to neural migration at day 19-28
assymmetry
unuilateral mandibular hyperplasia
zygomatic arch hypoplasia
high arched palate
malformed pinna
Treacher collins syndrome
deofrmity of 1st and 2nd brachial pharyngeal arches
hypoplasitc or missing zygomatic arch
hypoplastic mandible
deformed pinna
anti monoyloid slant palpebral fissures
Achondraplasia
deformity of the endochondrial ossification ]defects in long bones, casues short bones = dwarfism
defects in base of skull
depressed nasal bridge
retrusive middle thrid of face
Couzon’s syndrome
premature closure of cranial sutures - coronal and lambdoid
poptosis
prominent nose
Class 3
narrow spaced teeth
Apert’s syndrome
premature closure of all crainal sutures
maxiallry hypoplasia
AOB
Class III
narrow spaced arch
deafness
Parrot beak nose
Neurocranium
forms protective case around the brain
flat bones of the vault - develop intramembraously
endochondral elements of base of skull
Viscerocranium
forms the skeleton of the face
Meckel’s cartilage
prceeds the mandible
Nasal capule
primary skeleton of upper face
What are the 3 main sites of secondary cartilage formation in mandible
condylar cartilage
coronoid cartilage
the symphyseal end of each half of bondy mandible
What can happen if there is a failure of fusion of maxiallry process and nasal elevations
cleft lip/palate
formation of face
first 8weeks after fertilisation
formed from migrating neural crest cells
Pharyngeal arches formed
week 4 from migrating neural crest walls and migrate to form frontonaasal process
Contains cranial nerve V
2nd pharnygeal arch
33days
grows over 3rd and 4th pharyngeal arches which form the sinus crevicalis
