ortho all Flashcards
why might space need to be created?
crowding relief
correct incisor relationship - OJ/OB
correction of molar relationship
compensate for skeletal discrepancy
how can space be created?
growth + functional appliance distal movement expansion ID enamel reduction extractions
how is distal movement done?
implants
non compliance distaliser
how is expansion caused?
quadhelix
rapid maxillary expiser
why might a’s and b’s be extracted?
caries
trauma
ectopic perm teeth
why might c’s be extracted?
caries trauma transitional incisor crowding correct centre line ectopic perm canine
when should you be able to palpate the canines?
what age should you take radiographs if not palpable?
what xrays should be taken to find them?
if palatally ectopic canine how would you treat?
- age 9 onwards
- 10 years
- parallax
- extract c and allow to erupt
when would you extract d’s?
caries infraocclusion hypodontia ectopic perm teeth ectopic perm canine crowding
when would you extract e’s?
caries ectopic 5s infraocclusion hypodontia impacted 6
why would max centrals be extracted?
trauma
pathology
severe ectopia/dilaceration
why would you extract max laterals?
contralateral absent
inavginated odontome
palatal exclusion
resorption by 3
why would mandibular incisors be extracted?
lingual exclusion
fanned incisors
tooth size discrepancy
why would you extract canines?
severely displaced/crowded out of arch
palatal/buccal ectopic 3
why are first premolars extracted?
ant/post crowding
OJ reduction
common tx with fixed appliance for class 1 crowding
why are second premolars extracted?
crowding
hypoplasia
poor 4-6 contact
correctino of tooth size discrepancy
why might 1st perm molars be extracted?
poor prognosis
compensation
why might 2nd molars be extracted?
remote from ant crowding
extract 7 as prophylaxis for crowding, 8 to erupt normally
extract upper 7s to aid distal movement
severe displacement
why might third perm molars be extracted?
orthognathic surgery
what is the definition of a fixed appliance?
any appliance attached to the teeth by bands and brackets
moves teeth by means of the brackets and their attachment on the bands
appliance cant be removed by the patient
what movements can removeable appliance cause?
tipping
intrusion/extrusion
what movements do fixed appliance causes?
bodily movements
intrusion/extrusion
rotation
torque
what are edgewise appliances?
straight slot cut into brackets
tooth position determined by bends in archwire or orientation of bracket slot/base
what are pre adjusted
minimal archwire bends
: slot pre angulated/pre torqued?
what movements can contemporary fixed appliances cause?
optimal tooth control bodily movement - space closure/OJ reduction rotations intrusion/extrusion - OB reduction uprighting root torqueing
what types of fixed appliance exist?
labial - pre adjusted edgewise
tip edge
- lingual
what are methods of ligation?
conventional ligation
self ligation
what type of bends can be caused?
1st order - in/out
2nd order - tipping
3rd order - torque
what are the components of fixed appliances?
brackets molar bands/buccal tubes archwires ligatures auxilliaries
how are fixed appliances fixed to the tooth?
composite resin sandwhich
- unfilled resin/filled resin/unfilled resin
etch - 37% phsophoric acid, self etch primer
how are brackets placed?
apply to tooth with tweezers
position using - probe and bracket gauage
what tubes are situated on molar bands?
archwire tubes
auxillary tubes
headgear tube
how are molar bands placed?
band cement - reinforced GI, compomer
position with finger, mershon band pusher and bite stick
what materials are used as archwires?
nickel titanium
stainless steel
beta titanium
glass/composite
what are nickel titanium wires used for?
alignment/levelling
finishing/detailing
what are stainless steel wires used for?
OB reduction
OJ reduction
space closure
what are auxillaries?
elastic bands
springs
palatal/lingual arches
headgear
what is elastic traction used to treat?
class 2 and 3
what are temporary anchorage devices used for?
anchorage
distal movement
what are the 6 points to a good occlusion?
class I molars no spaces no rotations normal angulation normal inclination flat occlusal plane
how are fixed appliances removed?
bracket removing forceps
band removing forceps
what are types of retainers?
removeable - hawley type, pressure formed
fixed - wire/other
what problems can occur during fixed appliance tx?
demineralisation/caries gingivitis perio destruction soft tissue trauma root resorption pulp death enamel fracture
what are functional appliances used for?
growth modification and guidance
what occlusions are functional appliances used to treat?
class 2 and 3
what are indications for functional appliances?
good dental health motivated pt pre adolescent growth phase skeletal discrepancy mild/mod increased OJOB proclined max incisors well aligned arches co incident centre lines
what are contraindications for functional appliances?
poor motivation age over 14 poor dental health condylar disease unfavourable facial growth
wht are advantages of functional appliances?
removeable - easy to clean around
avoid extractions if good response to tx
accelerates skeletal growth
reduce trauma incidence
what are disadvantages of functional appliances?
bulky appliances compliance speech soft tissue trauma lack of detailed movements
what are types of functional appliances?
removeable - energy in muscles and ligaments used to move teeth
fixed - energy in appliance moves teeth
what are removeable functional appliances?
flat ant biteplane twin block bionator activator fraenkel teuscher
how does a biteplane work?
discludes the mandible
allows growth potential to be realised
what are types of fixed functional appliances?
herbst
jasper jumper
twin block
what are the commandments for functional appliance use?
25 hour wear
removed only for cleaning, sport and musical intstruments
work best during meals and talking
what is full success with a functional appliance use?
partial success?
2mm overjet
reduction is less than 50% value of OJ at start of tx
treatment timing…
in deciduous dentition?
mixed?
permanent/adults?
- unstable, skeletal pattern re establishes
- 1-2 years pre adolescent growth spurt
- functional appliances are not an alternative to surgery
at what age should a functional appliance/headgear used?
age 10
how is bone laid down?
within cartilage - endochondreal
within membrane - intramembranous
bone then remodels by laying down or removing bone form the surface
what are the joints in the head?
all bones connect to each other via sutures except the TMJ joint
describe the calvarium?
6 fontanelles at birth
fontanelles allow compresison of head during birth
intramembranous ossification
5/6 fontanelles fuse during first year of life - ant fontanelle closed by 18 months
what is craniosynostosis?
premature fusion of sutures on the calvarium - abnormal shaped head
describe the cranial base?
2 main areas of cartilage that lay down bone by endochondreal ossification
cartilage areas - sychondroses - sphenooccipital, sphenoethmoidal, inthersphenoid
bone lays down here and causes growth of cranial base
describe the nasomaxillary complex?
maxilla, nasal septum, zygomatic bones
intramembranous ossification
pushed forwards and down
describe the mandible?
endochondreal activity at the condyle
periosteal activity/surface remodelling
when is facial growth complete by?
16-17 yrs females
17-19 years males
mandible late growth in 20’s
what are supernumeraries?
additional teeth - can be exact copies - supplemental teeth or conical/tuberculates - tooth material but dont look like teeth
where do SN’s occur?
what are they called in the max midline?
what can they impede?
premaxilla
mesiodens
impede eruption
what are peg shaped incisors?
affects laterals
probs with spacing and aesthetics
associated with absent contra lateral
increased risk of ectopic canines
what is hypodontia?
congenital absence of one or more teeth
can be hereditary
U2’s L5’s
where is hypodontia most common?
what does it present with?
permanent dentition
delayed deciduous exfoliation
delayed perm eruption
what are neonatal teeth?
deciduous teeth that erupt at birth
can cause feeding problems
very mobile should be extracted
eruption cyst?
blue mucosa overlying an unerupted tooth
most common over es and 6s
asymptomatic
resolves as tooth erupts
what are impacted teeth?
deciduous or perm teeth that fail to erupt fully
what can eruption be due to?
obstruction
primary failure of eruption
insufficient space
ectopic teeth
what are infraoccluded teeth?
often called submerging
usually due to ankylosis adjacent teeth erupt and ankylosed teeth remain unchanged vertically - gives submerging appearance
- no perm successor, idiopathic
why might deciduous teeth be retained?
what is the tx?
missing perm successor or ankylosis
require xla if due to ankylosis because can defelct perm successor
leave in situ if missing permanent successor
how can trauma affect eruption?
can result in centre line shift
delayed eruption of perm successor - fibrous mucosa
intrustion of deciduous incisors can cause deflection of perm successor
what is a balancing extraction?
tooth xla on one arch take out contra lateral tooth
- do stop effect on centre line shift
what is a compensating extraction?
extract in one arch consider extracting the same tooth in opposing arch
what are serial extractions?
planned sequence of extractions to relieve incisor crowding in the mixed dentition
minimise demands of ortho
where do crossbites commonly affect?
what can they cause?
incisors and molars
displacement of tooth/jaw
tooth wear
easily corrected in mixed dentition
what does thumb sucking cause to teeth?
proclined upper ants
retroclined lower ants
buccal segment crossbites
reduced overbite/ant open bite
why might a median diastema cause?
normal dental development small teeth and large jaws missing teeth midling supernumerary prominent frenum proclined upper incisors
what are advantages of removeable appliances?
easy to clean good anchorage can move blocks of teeth cheap less chairside time less inventory easy to adjust
what are disadvantages of removeable appliances?
dependent on pt co operation tipping only speech can be affected retention difficult lower hard to wear
what tooth movements do removeable appliances cause?
tipping space maintenance bite opening crossbite correction single tooth movemetn
what are the components of a removeable appliance?
baseplate
activation
retention
anchorage
what materials are used to make removeable appliances?
stainless steel
elgiloy
acrylic
what is the job of the baseplate?
hold components together
active/passive
add biteplanes
minimise bulk so comfortable
what are ant biteplanes used for?
posterior?
ant - OB reduced by allowing eruption of perm teeth, and true intrusion of ant teeth
post - eliminates occlusal interferences anteriorly - can push tooth over the bite
what is the force of the appliance dependent on?
length, radius and stiffness of wire
how is the length of the wire increased in a mouth with reduced space?
add coils to wire
how do teeth move in a removeable appliance?
perpendicular to point of contact with tooth
what are palatal springs?
cause mesio distal and buccal movement
guard wire stops spring coming too far away from baseplate
point of application at 90 degrees to intended tooth movement
what are buccal canine retractors?
buccally placed canine to be moved palatally as well as distally
activated by winding up coil or adjusting ant arm
what is a z spring?
increases wire length where space is limited
spring perpendicular to palatal surface
activated by pulling a couple of mm away from baseplate at an angle of approx 45 degrees in direction of desired movement
what are t springs?
used to move teeth buccally - canine/premolar
activated by pulling away from baseplate at angle of 45 degrees
what are bows?
active/passive
retract proclined incisors
what is a roberts retractor?
0.5mm bow used to retract incisors
what are screws?
move teeth labio-lingually
transmits force via acrylic contacting the teeth
transversely expand
turn once a week then twice
what are adams clasps/cribs?
engage undercuts at mesial and distal
what are southend and c clasps?
use undercut beneath contact point
what are ball ended hooks?
engage undercuts interprpximally
what is anchorage?
resistance to unwanted tooth movements - force created as a reaction to actove component
how is anchroage increased?
clasp more teeth/move one or two teeth at a time, use lighter forces
what is used to fit an appliance?
adams pliers, spring forming pliers
marker
measuring device
acrylic trimmer
what is normal occlusion?
acceptable variation from the norm
- well aligned teeth
no crowding
class 1 incisor molar relationship
what is malocclusion?
irregularity in the occlusion beyond the accepted range of normal
what are genetic causes of malocclusion?
skeletal pattern
size of jaws and teeth
syndromes - cleft lip/palate
what can cause crowding?
big teeth small jaws
what is spacing?
small teeth
big jaws
what are environmental causes of malocclusion?
soft tissues - incompetent lips habits - thumb sucking pathology trauma - intrusion local factors
what are local factors affecting malocclusion??
additional teeth
missing teeth
fraenum
retained deciduous/early loss
what are risks of ortho tx?
demineralisation root resorption pulp damage gingivitis/perio damage soft tissue damage
what is demineralisation?
white marking = eventual cavitation
fixed appliances predispose to plaque accumulation bc cleaning is more difficult
labial side of fixed appliances, palatal surfaces of removeable
why does demineralisation occur?
poor oh
acidic attack
plaque, refined carbs, susceptible tooth, contact time with tooth surface
how to manage pts with demineralisation risk?
OHI diet advice F mouthwash identify and remove stagnation areas reduce flash around brackets use GI cement on bands bc F release
how much root resorption tends to occur during tx?
what teeth are commonly affected?
what are risk factors?
1mm incisors pts with resorption pre tx prev trauma root filled may increase risk
how can you lessen the risk of root resorption?
lighter forces
min tx length
repeat radiographs every 6 months
why is pulpal pain caused during ortho?
pulpal ischaemia as tooth starts to move
what are risk factors for pulp damage during ortho tx?
prev traumatised teeth - monitor with vitality testing
how can you manage pulp pain during ortho?
ischaemia is transient
2-7 days after fit/adjustment
how can perio tx be treated with ortho?
take care bc reduced support
use lighter forces
ensure perio disease controlled prior to tx
how can soft tissue trauma be caused from ortho tx?
traumatic ulceration
friction against appliance
archwire ends not tucked out the way
clumsy instrumentation
what can be used to relieve soft tissue trauma caused by appliances?
chlorhexidine to calm ulceration
wax application
what mechanisms are put in place in headgear to prevent injury?
neckstraps should prevent displacement
recoil prevented
what risks to ortho implants cause?
poor success bc no osseo integration
risk of perforation of roots/infection
what may pts be allergic to that you could come across in ortho?
latex
nickel
what are you looking to identify by viewing the patient anteroposteriorly?
view form side
look at position of maxilla to mandible
class1- mandible 2-3mm posterior to maxilla
class2 - mandible retruded relative to maxilla
class3 - mandible protruded relative to maxilla
what are you looking to indentify in the vertical?
pt viewed from side with teeth in ICP
- lower facial height - distance from eyebrow to base of nose should be equal from base of nose to lower chin
- FMPA - increased - lines meet before back of head, reduced, cross after head
what are you looking to identify when looking at pt in transverse?
degree of symmetry
occlusal plane symmetry
what should you examine re ortho about the lips?
lip competence
lip position relative to upper incisors
smile line
what should be noted about the tongue?
variations in shape/size
what habits should be enquired about re ortho?
thumb sucking
what do you want to know about the labial segment alignment?
aligned crowded or spaced
angulation relative to jaw base
rotations/displacements
inclincation of canines
what do you want to know about the labial segment?
overjet
overbite
ant crossbites
centrelines
what do you want to know about buccal segment alignment?
gen alignment and presence of spacing or crowding
rotated teeth or any displaced from arch
what is a class 1 incisor relationship?
lower incisor edges occlude or lie below cingulum of upper incisor
what is a class 2 incisor relationship?
div 1 - central incisors are proclined or of avergae inclincation and increased overjet
div 2 - upper incisors are retroclined and OJ is minimal or decreased
what is a class 3 incisor relationship?
lower incisor edges lie ant to cingulum
what are the divisions of a molar relationship?
class 1 - MB cusp of upper first molar occludes with MB groove of lower 1st class 2 - MB cusp occludes mesial to the groove class 3 - MB occludes distal to groove
what radiographs can be taken for ortho screening?
DPT
lareral ceph
upper ant occlusal
what is IOTN comprised of?
dental health component
aesthetic
what are the IOTN tx grades?
1 - no need 2 - little need 3 - moderate need 4 - great need 5- very great need
what is the IOTN aesthetic score component?
score 1 or 2 - none
score 3/4 - slight
score 5,6,7 - mod
8,8,10 - definite
