Ortho

Question 1

describe class 2 div 1 incisor and skeletal relationship

Answer 1

inciors - lower incisor edge lies posterior to cingulum plateau of upper incisors, overjet is increased
skeletal - maxilla lies anterior to mandible more than 2mm, class 2

Question 2

why might treatment be required for class 2 div 1

Answer 2

aesthetics - might be teased at school
increased risk of trauma - 5a, more than 9mm

Question 3

how can a class 2 div 1 be treated

Answer 3

accept - if low risk of trauma + not bothering pt
growth modification to correct skeletal relationship - upper and lower functional appliance, retrocline uppers, procline lowers, encourage growth of mandible, restrict growth of maxilla
fixed appliance - following functional or accept skeletal and camouflage
URA - not as common now, can tip teeth but wont correct relationship
orthognathic surgery - fixed before and after, if patient no longer growing and movement outwith limits of fixed appliance

Question 4

describe class 3 incisor and skeletal relationship

Answer 4

incisor - lower incisor edge lies anterior to upper cingulum plateau, overjet may be reduced or reversed
skeletal - mandible lies anterior to maxilla

Question 5

when would a class 3 be treated

Answer 5

pt affected by aesthetics
dental health affected - gingival stripping or recession
TMD problems
difficulty with function - chewing

Question 6

what treatment options are available to treat a class 3

Answer 6

accept - if no aesthetic or dental concerns
growth modification - usually not favourable, can get a reverse twin block if young enough
fixed appliance - camouflage skeletal relationship by correcting incisor relationship
URA - can use to expand maxilla or to tip upper teeth infront of lowers
orthognathic surgery - have to have stopped growing, move mandible back, bring maxilla forward, fixed appliance before and after treatment, can take around 3 years

Question 7

what are causes of an unerupted 21

Answer 7

supernumerary
trauma to deciduous
early loss of primary
retained primary
hypodontia
pathology

Question 8

what are signs of an unerupted 21

Answer 8

more than 6 months since condralateral erupted
lateral erupted
discolouration to primary

Question 9

how is a retained 61 treated

Answer 9

2 PA or OPT + Oclussal to locate
referral to paeds and ortho
leave and monitor - possible cyst or resorption
XLA and spontaneous eruption - unlikely if dilacerated, need space maintainer
XLA and chain bonded - difficult if dilacerated

Question 10

what age should canines be felt for

Answer 10

from age 9

Question 11

what are clinical signs of impacted canines

Answer 11

pattern of eruption is not symmetrical
discolouration of 2s
sequence of eruption not correct

Question 12

what are the risks of leaving unerupted canines

Answer 12

cyst formation
resorption of adjacent teeth
resorption of canine crown
ankylosis

Question 13

how can ectopic canines be treated

Answer 13

unable to align if too close to midline, too high (apical third of lateral), at 55 to midline
surgical removal
surgical exposure and chain
autotransplantation

Question 14

describe how parallax is used

Answer 14

using two radiographic films to locate an object, radiographs taken at different angels. if object moves in same direction as the tube head - it is palatally placed

Question 15

how is vertical parallax used

Answer 15

OPT and oblique occlusal - tube head moves up from opt to occlusal, if tooth appears higher up then palatally placed

Question 16

how is horizontal parallax used

Answer 16

using 2 pa radiographs at different angles - one more to RHS than the other
if object moves to right then palatally

Question 17

what are benefits of ortho tx

Answer 17

improve aesthetics, improve function, improve dental health

Question 18

what are the risks of ortho tx

Answer 18

relapse - will need some form of retainer life long, either removable or fixed
decalcification, need to have good patient selection, good OH, weakens enamel, more at risk of caries
root resorption - 1-5% chance but pt has to be aware
gingivitis and gingival recession - poor oh large cause but if thin gingival biotype then recession more likely with movement - increased sensitivity

Question 19

what should you check when delivering a ura

Answer 19

right appliance for right patient
check prescription is what you asked for
run finger over surface and check for rough areas
check wire for work hardening
insert appliance - check for areas of blaunching
check posterior retention - flyover then arrowhead
check anterior retention
activate appliance
demonstrate removing and inserting
get patient to remove and insert
review in 4-6 weeks

Question 20

what instructions should be given to a patient when delivering a URA

Answer 20

it will feel big and bulky, will get used to it
will be uncomfortable, means it is working, take pain relief as required
speech will be altered, practice reading aloud
excess salivation - will settle in 24 hours
wear 24 hours a day 7 days a week, including eating and sleeping
remove after meals and clean
remove during contact sports and store in hard container
avoid hard sticky foods - might damage the appliance, and be careful with hot drinks
poor compliance will increase treatment time
emergency contact details

Question 21

what are the benefits of a base plate

Answer 21

retention, anchorage and connector

Question 22

what are signs patient has been compliant

Answer 22

patient comes in wearing
patient can speak with appliance in
no excess salivation
signs of wear on the appliance
tooth has moved
active component no longer engaging tooth

Question 23

what is a flat anterior bite plane and how does it work

Answer 23

fabp is used to reduce overbite - acrylic is oj +3mm to ensure low incisors bite on acrylic
this creates a posterior open bite so molars continue to erupt until come into contact with one another - increasing OVD and reducing OB
space has then been created to reduce the OJ

Question 24

give the ARAB for reducing OJ + OB

Answer 24

a - roberts retractor 11-22 0.5mm HSSW + 0.5mm ID tubing
r - 16 + 26 adams clasp 0.7mm HSSW
a - moving more than 2 teeth, not good
b - self cure PMMA + FABP (OJ+3mm)

Question 25

give the ARAB for correcting anterior crossbite

Answer 25

a - 12 z-spring 0.5mm HSSW
r - 14, 16, 24, 26 adams clasp 0.7mm HSSW
a - only moving one tooth
b - self cure PMMA. + PBP

Question 26

give ARAB for retracting buccally placed canines + reduce OB

Answer 26

a - buccal canine retractor 13 + 23 0.5mm HSSW + ID tubing
r - 11+21 southend clasp 0.7mm hssw, 16+26 adams clasp 0.7mm HSSW
a - only moving 2 teeth
b - self cure pmma + fabp (oj + 3mm)

Question 27

give ARAB for retracting canines in line of arch + reduce ob

Answer 27

a - palatal finger spring 13+ 23 0.5mm HSSW + guards
r - 11+21 southend clasp 0.7mm HSSW adams clasp 16+ 26 0.7mm HSSW
a - only moving 2 teeth
b - self cure pmma + FABP (oj+3mm)

Question 28

give arab for expanding arch

Answer 28

a - midline palatal screw
r - 14, 16, 24, 26 - adams clasp 0.7mm HSSW
a - reciprocal anchorage
b - self cure pmma + PBP

Question 29

what is aetiology of unerupted canine

Answer 29

long path of eruption
if small lateral, less of a guide into eruption
crowding
ectopic position of follicle
genetics

Question 30

what are limits of fixed appliance

Answer 30

cant procline past 120
cant retrocline past 80
if severe skeletal - ANB greater than 8 or less than 0

Question 31

what is definition of class 2 div 2

Answer 31

lower incisor edge lies posterior to cingulum plateau of upper incisors, upper incisors are retroclined

Question 32

what are treatment options for class 2 div 2

Answer 32

growth modification - modified twin block with ELSA component, procline upper incisors to convert to class2 div 1
camouflage - accept underlying skeletal discrepancy
ura - reduce over bite
surgery

Question 33

what should be assessed in patient assessment for ortho tx

Answer 33

extra oral
* ap relationship - class 1,2, 3
* fmpa - lines should meet at back of head, either increased (meet to soon) or decreased
* asymmetry
* soft tissues - lips competent, lip trap, mentalis

intra oral
* incisor relationship
* molar relationship (mesiobuccal cusp of upper should lie on groove of lower)
* canine relationship (lower should be anterior to upper)
* crowding
* overjet
* overbite (complete or incomplete)