ALL ORTHO Qs Flashcards
aetiology of malocclusion (general)
skeletal - size/shape
muscle - form/function of muscles
dental - size of teeth in relation to jaw size
AP jaw discrepancy -class 1 definition -class 1 features and ceph
maxilla 2-3mm in front of mandible
-ceph - SNA - 81+_3/SNB - 78+_3/ANB - 3+_2
AP jaw discepancy - class 2 def -ceph features
-maxilla >2-3mm in front of mandible
ceph -SNA averege or increased/SNB - decreased
ANB>5mm
what is the eastmen correction
For every >1 degree than average, subtract 0.5mm of ANB/vice versa
AP jaw discrepancy - class 3 def -ceph features
mandible placed in front of maxilla
-SNA - decreased/SNB - average or increased/
ANB - <1 or negative
what is dento-alv compensation
the inclination of the teeth that compensates for the underlying skeletal pattern
how to determine AP jaw relationship
visual/palpate/ceph
what are the measurement points of:
- frankfort plane
- mandibular plane
- frankfort - orbitale/porion
- mandibular - menton to gonion
how to measure the vertical jaw relationship
FMPA - 27 degrees
LAFH - 50/50 clin 55% ceph
what does a backward mandibular growth rotation produce, values:
- FMPA
- LAFH
steeply inclined mand plane, AOB tendency
- FMPA >31 degrees
- LAFH ->55%
what does a forward mandibular growth rotation produce
- FMPA
- LAFH
Parallelism of jaws
deep OB
-FMPA - <23
-LAFH - <55%
what are the two transverse discrepancies
arch width
mandibular displacement
aetiology of malocclusion
skeletal dental ST BAD HABITS genetics and enviro
local causes of malocclusion
variation in: (5)
variation in tooth number " in tooth size/form abnormality of tooth position local ST abnormality local pathology
name 4 types of supernumerary and brief descriptions
- Conical - small peg shaped, mesiodens in midline
- Tuberculate - most likely cause of an unerupted central, paired/barrel shaped
- supplemental - extra teeth of normal morphology
- odontome - compound - many little teeth/complex - disorganised mass of dentine/pulp/enamel
when should alarm bells be ringing in terms of delayed eruption.
-why would a tooth not erupt
6mth after contralateral tooth
-no perm successor/ankylosed/ectopic sucessor/pathology
treatment for retained primary successor
if good prognosis, retain as long as poss.
Early ortho referral best
management of an infra occluded primary molar
- perm succesor
- no perm successor
• Management:
– Permanent successor? Obs. 1 yr
– No successor? Extract, keep if good prog
why would a tooth be lost early
- what is a balanced XLA
- what is a compensating XLA
trauma/caries/resorptio/early dental development
- balanced - tooth from opposite side of same arch
- compensating - tooth from opposing quadrant, minimise interference and maintain occ relationship
what teeth should be balanced/compensated
A/B's - no comp/balance C's - balanced to prevent midline shift D’s – small CL. shift, balance under GA? • E’s – not to balance – major space loss – upper>lower
when should children ideally be referred to an orthodontist
age 7-9yr
what is the definition of interceptive ortho
‘Any procedure that will reduce or
eliminate the severity of a developing
malocclusion’
spacing percentages in primary dention that translate to crowning in perm dentition -no spacing -<3mm -3-6mm >6mm
- No spacing 66% crowding
- < 3mm 50% crowding
- 3-6mm 20% crowding
- > 6mm No crowding
when should first perm molars be assessed, what should then happen
• Assessment 9 years
• Any doubts re long-term prognosis
refer for advice.
XLA rules of up/low 6’s
If extracting lower XLA upper
• Don’t balance with sound tooth.
• If extracting upper don’t necessarily
take lower
what features display the best time to XLA 1st perm molars
Ideally: • 7’s furcation forming • 8’s present • Class 1 av/reduced OB • Moderate lower crowding • Mild/moderate upper crowding
on average, when are roots completed in a tooth
3yr post eruption
define leeway space and the measurements for max/mand
Leeway Space: difference between
e,d,c and 3,4,5.
– Mx 1.5mm
– Md 2.5mm
when should upper canines be assessed
10yrs Assess position of upper canines from 10 years onwards • Should palpate by 11 years • Mobile C’s, symmetry
cause of deformity needing orthognathic surgery
family trait/race/congenital/deformity/trauma
Clinical exam prior to orthognathic surgery
E/O - AP relationship
front - vertical asymmetry/lip and nose morphology/horizontal asymmetry/ smile line
I/O - dental assessment/occlusal relationship/cetre lines/OJ/OB/incisor inclination/crowding/cleft
who’s part of the multidisciplinary team of an orthognathic surgery team
psychologist/OMFS/restorative dentist/orthodontist/speech and language therapy/oral hygiene/technologist
How can combined ortho/surgical treament work
-tooth alignment/eliminate crowding/alteration or co-ordination of arches/correct incisor inclination/flatten occlusal plane/surgical fixation/post surgical ortho
diagnosis terms for:
maxilla
mand
chin
max - retrognathic/prognathic(anterognathic)/vertical excess/vertical deficiencey
mand-prognathic/retrognathic
chin - prognecia/retrognecia/vertical excess/vertical deficiency
name some surgical procedures in orthognathic surgery
max - le fort 1 osteotomy/anterior maxillary osteotomy
mand - andvancement (sagittal split osteotomy)/VSSO
chin - advancement, set back, rotation/augmentation/reduction
variation of tooth form
macrodontia
microdontia
abnormal
how many people are affected by ectopic canines (%)
1-2%
clinical assessment of ectopic canines
visualisation and palpation
colour /mobility of 2/c
inclination of 2
Rg - OPT and anterior occlusal for parallax
ectopic canine management
- leave and observe = prevention
- surgical exposure and ortho alignment
- XLA of c - encourage movement
- retain c and observe
- XLA
- Transplant
ectopic central incisor management
- surgical exposure
- XLA supernumerary
- bond gold chain
- ortho traction
- fixed appliance
- bonded retainer
class 2 div 1 definition
- what percetage of malocclusions
- main concerns
the lower incisor edges lie posterior to the cingulum plateau of the upper incisors. Incisors are often proclined/aaverage inclination and theres an increased OJ
- 15-20%
- aesthetics/trauma
class 2 div 1 features -AP -ST Dental findings -Habit
AP - class 1/2 ST - incompetent lips, try to achieve anterior oral seal -through pushing lower lip up behind up incisors, use of circum-oral musculature, posture mandible forward
-dental features = >OJ, varied OB, good alignment and spacing, class 2 molar relationship DRYING OF GINGIVAE - gingivitis risk
occlusal features of a sucking habit
proclined upper inc
retroclined low inc
narrow arch +_ unilateral post crossbite
AOB
management options of class 2 div 1
- accept
- growth mod - headgear/twinblock (functional app), 10yrs
- URA - robert’s retractor
- fixed appliances
- Orthognathic surgery - pre and post ortho
mode of effet of functional appliance in class 2 div 1
DENTO-ALV CHANGE
distal movement of up dent/mesial movement of low dent/retroclination of up inc/proclination of lower inc
minor skeletal change
what features would encourage the use of a URA in class 2 div 1
favourable OB/mild class 1 or 2/OJ due to incisor proclination
class 2 div 2 definition -% of all malocclusions
The lower incisor edges lie posterior to the cingulum plateau of the upper incisors. The upper incisors are often retroclined and there is a minimal OJ/slight increase
-10%
features of class 2 div 2
- AP
- Vertical
- ST
- Dental
AP-mild/mod skeletal class 2
Vertical - REDUCED FMPA, forward rotational mandible growth patttern
ST - high lip line/marked labiomental fold/high masseteric forces
-dental- retroclination of up incisors, reduced IIA/reduced OJ/2’s crowded/mesio-labially rotated 2’s
reduced arch length
>OB
treatment options for class 2 div 2
-accept and monitor
-Growth mod - mild/mod skel 2 = modified twin block
-Camouflage
Orthognathic surgery
what would occur during the camouflage stage of the tretament of a class 2 div 2
accept the underlying skel base and aim for class 1 incisor relationship = reduce OB correct inter-incisal angle = palatal root torque - p incisors/procline lower incisors
class 3 definition % of all malocclusion
the lower incisor edges lie anterior to the cingulum plateau of the upper incisors. There is a reversed or reduced OJ
-3-8%
features of class 3
- AP
- vertical
- transverse
- dental
-AP - class 3
-Vertical - May be associated with average, increased or
reduced vertical proportions
– Frankfort Mandibular Plane Angle
– Anterior Facial Height proportions
– Lateral cephalometry
• ↑FMPA and anterior open bite more complex
to treat
-Transverse- bilateral posterior crossbites
-Dental - Class III incisor relationship • Class III molar relationship (not always) • Tendency to reverse overjet • Overbite will vary • Crossbites – Anterior and Posterior (buccal) Alignment – Maxilla often crowded – Mandible often aligned or spaced • Dentoalveolar compensation – Proclined upper incisors – Retroclined lower incisors • Tendency for displacements on closing
treatment options for class 3
- Accept and Monitor
- Interceptive with URA - procline up inc over bite
- Growth Modification - reverse twin block/frankel III/chin cup/protraction heagear+RME
- Orthodontic Camouflage
- Orthognathic surgery
features of a frankel III appliance
Pellotes (Shields) labial to upper incisors to hold lip away • Palatal arch to procline the upper incisors • Lower labial bow to retrocline the lower incisors
correct age and features for protraction headgear
Correct age (young age 9/10) • Co-operative patient • 14 hour/day protraction facemask wear • 400g/side • ± Rapid maxillary Expansion
favourable features for use of camouflage in class 3
Growth stopped
– Mild to moderate Class III Skeletal base ANB >0˚
– Average or increased overbite
– Able to reach edge to edge incisor relationship
– Little or no dento-alveolar compensation
order of ST exam
lip competent lip trap nasolabial angle smile line tongue
overview of intra-oral exam in patient assessment
- chart teeth
- poor prog
- OH
- tooth condition
- perio
- wear
Crowded measurements
-methods of measuring crowding
<4mm - mild 4-8mm - mod >8mm - severe -space available/space required -mixed dentition analysis -overlap technique
Order of assessment IN OCCLUSION
- incisor class
- OJ
- OB
- centre lines
- molar relationship
- canine relationship
- crossbite
- mand displacement
definition of OJ
Horizontal distance between labial surface of tips of upper incisors and the surface of lower inc
definition of OB
vertical overlap of incisor teeth
special inv for ortho
Rg -OPT
study models
Planning models - Kesling (cut teeth off and move), Diagnostic - fixed pros
Problem list - MOCDOO meaning
Missing OJ Crossbite Displacement of CP OB Other
CLP - how many
- % sporadic
- ratio of M:F
1:700 live births
70% sporadic
3M:1F
aetiology of CLP
genetic - fam H/syndrome/sex ratio/ethnic
enviro - alcohol/drugs (antiep)/Low SES/smoking/multivitamins
CLP patient journey
3mth - lip closure
6-12mth - palate closure
8-10yr - alv bone graft
12-15yr - definitive ortho
18-20yr - orthognathic surgery
members of cleft care team
surgeon cleft nurse geneticist ENT respiratory psychologist dental team speech therapist
dental issues with CLP
hypodontia - missing teeth caries impacted teeth crowding growth
member of dental team for CLP
orthodontist oral surgeon paediatric dentist restorative dentist orthodontic therapist dental therapist
basic order of orthopaedics
presurgical orthopaedics
expansion/bone graft
definitive ortho
orthognathic surgery
definitions:
- hypodontia
- anodontia
- severe hypodontia
Hypodontia – Congenital absence of one or more teeth • Anodontia – Complete absence of teeth • Severe hypodontia – 6 or more congenitally absent teeth
prevalence of hypodontia, M:F
- most likely teeth
- prmary teeth occurence
Prevalence approx. 6% (excl. 8’s)
• 6.3% F, 4.6% M in European population
-lower 5’s, upper 2’s, up 5’s
• 0.9% primary dentition
what are the clinical signs of hypodontia
Delayed or asymmetric eruption • Retained or infraoccluded deciduous teeth • Absent deciduous tooth • Tooth form
what is the occurence % of missing laterals
1-2%
associated issues with hypodontia
microdontia !!!!!!
cleft lip and/or palate
malformation of other teeth
short root anomaly
impaction
delayed formation and/or delayed eruption other teeth
crowding and/or malposition of other teeth
maxillary canine/first premolar transposition
taurodontism
enamel hypoplasia
altered craniofacial growth
name 2 conditions associated with hypodontia
ectodermal dysplasia
down’s syndrome
Hypodontia care pathway
GDP recognition
• Referral to Specialist Orthodontist
• If GDH&S: Initial assessment in Orthodontics
and allocate when appropriate to Hypodontia
clinic (Orthodontic & Restorative input)
assessment and planning components for hypodontia
History • Extra-oral examination • Intra-oral examination – Orthodontic aspects – Restorative aspects • Investigations • Problem list • Definitive Plan • Retention / maintenanc
special inv for hypodontia
Study Models • Planning models – Kesling, diagnostic • Radiographs • Photographs • Conebeam CT
missing upper laterals - treatment options (general)
-detailed
Accept • Restorative alone • Orthodontics alone • Combined orthodontic & restorative treatment
-Open space / Close space RBB Implant Autotransplantation Conventional bridgework Partial denture
CLOSE - Space closure plus
Simple
ADV and DIS of RRB
• Advantages • Relatively simple • Do when young (complete treatment) • Non-destructive • Can look good • Place on semipermanent basis
• Disadvantages • Fail rate • Appearance sometimes not good, (try again, new materials) • Orthodontic retention needs are high
fixed appliance ADV
DIS
- move multiple teeth at once
- bodily movement
- no need for patient compliance
- control of root movement
- more complex tooth movement
dis
OH needs to be excellent
risk of iatrogenic damage
Poor intrinsic anchorage
components of a fixed appliance
brackets modules arch wire band anchorage components force generating components auxilliaries
what is torque
what is tip
bucco-lingual angulation of tooth
-determined by angle between bracket base and slot
tip - mesio-distal angulation of tooth
Properties of nickel titanium
shape memory
flexible
-light continuous force
>friction than SS
name 3 force generating components
elastic power chain/intraoral elastics/active ligatures
where do class 2 elastics fit onto where do class 3 elastics fit onto
class II - low 6 to upper canine
class III - upper 6 to lower canine
name some forms of retention
- pressure formed retainer - cover all teeth, removable, easy to clear, can get lost/broken, easily replaced, can have prosthetic tooth for aesthetics
- hawley’s retainer - labial bow
- resin bonded retainer - for rotation/diatema/space/ectopic canines
types of movement achieved using a quadhelix appliance
unilateral contraction fan expansion bilateral expansion of post teeth and canines molar rotation CLP expansion asymmetrical expansion
what is the purpose of anance button and transpalatal arch
-how much space between arch wire and GM
provide anchorage of molar teeth
-4-6mm between arch wire and GM
risks of ortho treatment
relapse gingival recession decalcification root resorption loss of vitality periodontal bone loss failure of treatment
difference in adult treatment to children
- issues
- lack of growth = growth mod not an option, OB treatment more difficult/can only expand max arch with surgery
- periodontal disease -
