ortho learn Flashcards
IOTN grade 5 order and components
5i - impacted teeth (except 8s)
5h - extensive hypodontia (>1 in a quadrant)
5a - OJ >9mm
5m - reverse OJ >3.5mm, masticatory and speech difficulties
5p - defects CLP and other CF anomalies
5s - submerged deciduous teeth
IOTN grade 4 order
4h 4a 4b 4m 4c 4l 4d 4e 4f 4t 4x
IOTN 3f
deep OB complete on gingival or palatal tissues, but no trauma
4a
OJ >6mm less than or equal to 9mm
4b
reverse OJ >3.5mm, no masticatory or speech difficulties
4m
reverse OJ >1mm <3.5mm, masticatory and speech difficulties
4c
A/P CBs with >2mm discrepancy between RCP and ICP
4l
posterior lingual CB with no fct occlusal contact in one or both buccal segments
4d
contact displacements >4mm
4e
extreme lateral or anterior open bites >4mm
4f
increased and complete OB with gingival or palatal trauma
pt selection for growth mod for increased OJ
growing pt pt concerns pt motivation dental health risk large dentoalveolar contribution to aetiology absence of significant crowding increased OB
how does position in the arch affect crowding?
the further back in the arch the more marked the effect on crowding
anterior CB problems
toothwear
gingival recession
displacement on closure
diastema aetiology
developmental generalised spacing hypodontia (absent 2s) midline supernumerary proclination of U incisors low frenal attachment pathology
aetiology of impacted FPMs
eruption angle
ectopic cyst
morphology of E crown
small maxilla
consequences of impacted FPMs
pulpitis of E
premature exfoliation of E
UE U1 if pt <9yrs
likely to have open apex and still potential for spontaneous eruption (80% will erupt spontaneously)
class 2 div 2
L incisor occludes posterior to the cingulum plateau of the U incisor
U incisors retroclined
OJ reduced but can also be increased
hypodontia presentation
delayed/asymmetric eruption
retained/infra-occluded primary teeth
absent primary tooth
tooth form
in-out control
relative bucco-lingual position of teeth
determined by depth of bracket base
tip
MD angle of tooth - angle tooth makes to horizontal along line of arch
- all teeth tip mesially
angle of horizontal slot
round AW uses
tipping and vertical tooth movements
torque
BL angle (inclination) of tooth
determined by angle between bracket base and slot
only if rectangular wire - engages wall of slot
CLP dental issues
missing teeth impacted teeth crowding growth (class 3) caries
buccally placed canines exposing
apically repositioned flap to preserve attached mucosa
CLP pt journey
lip closure 3m palate closure 6-12m alv bone graft 8-10yrs definitive ortho 12-15yrs surgery 18-20yrs
tack/spot welding
base metal melted
soldering
only filler metal melted
flux powder
class 2 div 1
L incisor edges lie posterior to cingulum plateau of U incisors
increased OJ
U central incisors proclined or av inclination
tipping force
35-60g
bodily movement force
150-200g
intrusion force
10-20g
extrusion force
35-60g
rotation force
35-60g
torque force
50-100g
18-8 SS
72% Fe 18% Cr 8% Ni 1.7% Ti 0.3% C
tooth eruption
pre-eruptive tooth movement intra-osseous eruption mucosal penetration pre-occlusal eruption post-occlusal eruption
theories for ortho tooth movement
differential pressure theory
piezoelectric pressure theory
mechanochemical pressure theory
piezoelectric pressure theory
piezoelectric currents generated when crystalline structures such as bone are deformed
compression side more +, tension side more -
OB and OC get preferentially recruited to certain sides
differential pressure theory
force =
tension areas - deposition
compression areas - resorption
light forces
hyperaemia within PDL OB and OC appear resorption of LD from pressure side apposition of osteoid on tension side remodelling of socket "frontal resorption" PD fibres reorganised gingival fibres appear not to become reorganised but remain distorted slow tooth movement
EC bone formation
hyaline cartilage precursor
centres of ossification
base of skull
how do maxilla and mandible develop?
IM but are preceded by a cartilaginous facial skeleton
meckel’s cartilage precedes mandible
nasal capsule primary skeleton of upper face
why do you get more space if you ext L4s?
less mesial drift
mechanochemical pressure theory
mechanical stress
release of neuropeptides from nerve endings
stimulate FBs, endothelial cells and alv bone
FBs also comm with OBs and OCs
alv bone and PDL remodelling = tooth movement
mod force
occlusion of PDL vessels on pressure side
hyperaemia of PDL vessels on tension side
cell-free areas on pressure side (hylinisation)
- no cells, not dead but nothing going on so can’t resorb
period of stasis
increased endosteal vascularity
“undermining resorption”
increased OC activity - get OC coming in and nibble from below
sudden movement of tooth CLUNK
- tooth may become slightly loose
healing of PDL - reorganisation and remodelling
excessive force
necrosis undermining resorption resorption of root surfaces pain permanent change
where does post-natal growth occur?
sutures
synchondroses
surface deposition
risks of ortho tx
decalcification root resorption relapse ST trauma recession/hyperplasia loss of perio support headgear injuries E fracture and toothwear loss of vitality allergy poor/failed tx
adult differences ortho to children
lack of growth PDD - ongoing or prev missing/heavily Rx teeth physiological factors adult motivation
MOCDO
Missing teeth OJs CBs Displacement of CPs OBs
