Ortho Flashcards
what is a supernumerary tooth
additional tooth to normal number of dentition
describe 4 types of supernumerary teeth
- conical = peg, small, mesiodens
- tuberculate = paired, barrel shaped, commonly impede central incisor eruption
- supplemental = additional tooth with normal morphology, usually laterals
- odontome = complex [disorganised mess of enamel, dentine, pulp], compound [discrete denticles]
what effects can supernumeraries have on permanent dentition
- delayed/failed eruption
- retained primary
- ankylosis
- RR to adjacent teeth
- cyst formation
- crowding, impaction
- ectopic position of permanent teeth
- diastemas
9 y/o attends and you discover they have a persistent thumb sucking habit
-> what occlusal features might you see
proclined UI, retroclined LI, AOB, unilateral posterior cross bite, narrow upper arch
what does BSI stand for
British standards institute
BSI definition of class 2 division 1 incisor relationship
the LI edges occlude posterior to the cingulum plateau of the UI
UI are proclined, OJ increased
pt with class2div1 wears a twin block for 9months
OJ is reduced from 10mm to 2mm
list 6 possible changes that functional appliances can produce to allow this
- tipping of teeth = retrocline UI, procline LI
- dentoalveolar compensation = posterior movement U, labial movement LI
- GM = restricts maxillary growth and slight mandibular growth
- harnesses growth of soft tissues and musculature
list ways the skeletal base relationship can be assessed clinically in AP plane
- visual assessment
- palpation skeletal bases
- lateral cephalometry
fill in the blanks for class 1 skeletal base
the mandible is x posterior to the maxilla
2-3mm
cephalometric analysis reveals pt has ANB of 8*
what does this suggest
moderate class 2 skeletal discrepancy
list ways the skeletal pattern can be assessed clinically in the vertical plane
- FMPA
- LAFH/TAFH [facial proportions]
what is the BSI classification of class 3
the LI edges occlude anterior to the cingulum plateau of the UI
the OJ is reduced or reversed
what is a balancing XLA and when may you consider it
XLA of the same tooth from the opposite side of the arch
to prevent midline shift
XLA infra-occluded D
when is the ideal time to treat an anterior cross bite
in the mixed dentition
AS SOON AS PROBLEM HAS BEEN DETECTED
list features of an anterior cross bite that make it favourable for tx with a URA
- palatally tipped tooth in crossbite [single tooth]
- adequate space
- good OB to aid stability
URA design for 21 in crossbite
A = z-spring 0.5mm HSSW palatal on 21
R = Adam’s 6/6 0.7mm HSSW
Adam’s D/D 0.6mm HSSW
A =
B = PBP, self-cure PMMA
give an alternative to z-spring for treating anterior crossbite in a URA
- screw appliance
- T-spring
12 y/o presents with developmentally absent U2’s, 5’s and 8’s
what is this called
- hypodontia
outline potential treatment options for missing U2’s hypodontia
space open => RPD, resin retained cantilever bridge, implants in the future
space closed => restorative tx to make canine look more like lateral and bleach
name syndromes associated with hypodontia
- CLP
- Down syndrome
- Ectodermal dysplasia
name MDT members for hypodontia
- paediatric specialist
- orthodontist
- restorative specialist
what is the % for developmentally absent teeth for primary + permanent teeth
- primary = 0.9%
- permanent = 6%
pt has 12mm overjet, well-aligned arched and ectopic canines
what are possible complications
OJ = increased risk of trauma UI, psychological effect of teasing, bullying, low self-esteem
ectopic canines = retained C’s, RR adjacent teeth, ankylosis, cyst formation
dental complications of dental retainer
removable = easily broken/lost, non-compliance
fixed = can debond, caries, need excellent OH, perio, soft tissue irritations, can alter occlusion, wire can fracture
pt has posterior crossbite with class 1 dentition
design a URA
A = mid palatal screw
B = Adam’s 6/6/4/4 0.7mmHSSW
A =
B = PBP, self-cure PMMA
->what does right deviation of the mandible mean
->what problems may pt suffer if not treated
mandibular displacement due to inter-arch discrepancy
TMD, muscle fatigue, mastication issues, facial asymmetry, parafunctional habits, toothwear
fluoride methods to prevent decalcification
dose + frequency
- toothpaste 1450ppm 2 x day
- FV 22,600 ppm 4x year
- tablet 1mg 1xday
- MW 225ppm 1x day
methods other than fluoride to prevent decalcification
- tooth mousse CPP-ACP
- excellent OH
- dietary changes
- FS
list 8 potential risks of orthodontic tx
- relapse
- decalcification
- root resoprtion
- failure to move
- soft tissue irritation
- loss of pulp vitality
- staining
- allergic reaction
- gingival recession
how would you assess pt AP relationship
- visual assessment
- palpation of skeletal bases
- lateral cephalometry
4 intra oral features of class 3 incisor pt
- reverse or reduced OJ
- class 3 molars
- reduced OB
- AOB
- edge-edge occlusion
- anterior crossbite
- displacement on closure
what systemic condition may the pt have if mandible keeps growing
acromegaly
design URA to tx anterior crossbite 12
A = z-spring 12 0.5mm HSSW
R = adam’s 4/6 0.7mm HSSW
A =
B = PBP, self-cure PMMA
what characteristics of dentition makes an anterior crossbite suitable for tx with a URA
- 12 palatally tipped
- adequate space
- good OB to aid stability
- only one tooth being moved
what 5 factors can resist displacement forces
- gravity
- mastication
- active component
- speech
- tongue
what information related to a pt provision of orthodontic care should you provide when referring a pt
- skeletal class
- incisor class
- medical history
- previous trauma
- pt details = age, etc
pt comes GDP with a debonded bracket
what do you do
account for all components, ask pt what happened
assess for soft tissue lesions, remove wire and bracket, refer back to ortho
MAKE SAFE
pt comes to GDP with demineralisation around his ortho brackets
what do you do
inform pt, why this happened
reinforce OH, high fluoride TP, fluoride varnish, fluoride mw, tooth mousse, diet advice
what are the long term risks of loss of upper incisor teeth
- poor aesthetics
- reduced function
- shifting of teeth
- overeruption LI
- impacted speech, occlusion
- bone resorption
- poor labial profile
what are the long-term risks of XLA UI and making RPD
- retention/stability
- worse aesthetics
- loss of mechanoreceptors in area
- flabby ridge formation
- caries, perio, candida risk
- long-term ridge resorption and need for adjustments
what are the uses of URA
- tipping of teeth
- space maintainer
- habit breaker
- maxillary expansion
- overbite reduction
- retainer
- retracts buccally placed canines
design a URA to reduce an 8mm OJ and OB, the 4’s are missing
A = Robert’s retractor 12-22 0.5mm HSSW + 0.5mm ID tubing
R = Adam’s 6’s/5’s
A =
B = FABP OJ + 3mm, self-cure PMMA
give advice to pt when fitting URA
- will feel big and bulky
- initial excess salivation 24hrs
- impinge on speech, try reading aloud
- initial discomfort, shows it is working
- wear 24/7 including sleeping and eating
- remove after meals to clean with soft brush
- remove and store for contact sports
- avoid sticky/hard foods and be cautious with heat
- non-compliance will significantly lengthen tx time
- emergency contact details
outline the delivery of a URA
- check pt details match
- check design matches
- feel for any sharp areas
- check integrity of wire
- try in and check for areas of blanching
- check posterior retention = arrowheads, flyovers and engaging undercut
- same for anterior
- activate for 2mm movement a month
- demonstrate insertion and removal, ensure they can do it
review 4-6 weeks
when should you treat an anterior crossbite
as soon as detected
what features make an anterior crossbite useful for URA tx
- single tooth movement
- tooth in crossbite is palatally tipped
- good overbite/increased to aid stability
- adequate space for movement
what is the incidence of hypodontia in the uk
6%
what 3 teeth in order are the most commonly missing
excluding 8’s
L5, U2, U5
how may hypodontia present to GDP
- retained primary
- shifting of adjacent teeth
- no eruption of tooth within 6 month of contralateral
- peg laterals
- tapered centrals
- asymmetric/delayed eruption
- infra-occluded primary
- absent primary
what are the tx options of 2’s hypodontia
- do nothing, accept
- restorative alone
- orthodontics alone
- combined ortho and restorative
members of hypodontia MDT
- GDP
- orthodontics
- paediatric dentist
- restorative dentist
- prosthodontist
- radiologist
- oral surgeon
what age should you palpate canines
start at 8 years
how to localise canine position
parallax technique
- OPT + AOM vertical
- 2 PA’s horizontal
must be change in position of x-ray tube between the 2 radiographs
age range to intervene for ectopic canines
10-11 if cannot palpate
how long after XLA c’s should you review
[ectopic canines]
6-12 months
tx options for ectopic canine
- accept
- interceptive xla c
- fixed appliance and surgical exposure with orthodontic traction [open/closed]
- surgical removal canine
- autotransplantation
what is a supernumerary
extra tooth in addition to normal series/number of teeth
where are supernumeraries most likely to occur
near midline
mesiodens
maxilla
4 types of supernumerary
- conical = small, peg shaped, mesiodens
- tuberculate = pair, barrel, common cause unerupted central
- supplemental = extra of same mprhology
- odontome = complex [disorganised mess], compound [discrete denticles]
supernumerary effect on dentition
- delayed eruption
- ectopic position
- diastema formation
- root resorption to adjacenet
- ankylosis
- retained primary
- crowding
signs of thumb sucking
- proclined UI
- retroclined LI
- AOB
- unilateral posterior crossbite
- narrow maxillary arch
BSI classification class 2 div 1
lower incisors occlude posterior to the cingulum plateau of the upper incisors, UI proclined or average, OJ increased
functional appliance can be used to reduce OJ
name 8 ways how
- Retroclination of UI
- Proclination of LI
- Mandibular growth encouragement
- Maxillary growth restriction
- Improved lip competence by posturing mandible forward
- Altered tongue positioning
- Mesial movement lowers
- Distal movement uppers
what clinical signs can indicate impacted canines
- retained c
- delayed eruption >6mths since contralateral
- mobility lateral
- discolouration lateral/c
- distal tipping 2
- not erupted by 11 y/o
- cannot palpate
risks of impacted canines
- RR adjacent teeth
- aesthetics
- cyst formation
- drifting of adjacent = loss of space
- ankylosis
incidence of CLP in UK
1 in 700
general health implications of CLP
- impaired feeding
- impaired function
- impaired speech
- ear issues as cannot clear
- ear infections
- hearing loss
dental features of CLP
- hypodontia
- crowding
- impacted teeth
- high caries risk*****
- poor maxillary growth, 20% class 3
outline 5 tx stages for CLP pts
- 3-6 months = lip closure
- 6-12 months = palate closure
- 8-10 years = alveolar bone graft
- 12-15 yrs = orthodontics
- 18-20yrs = surgery
CLP MDT members
- GDP
- orthodontist
- speech and language
- ENT
- respiratory
- psychologist
- CNS
- GMP
class 3 incisor relationship
lower incisor edges occlude anterior to the cingulum plateau of the upper incisors, OJ is reduced or reversed
what is dentoalveolar compensation
movement of the teeth as a result of underlying skeletal discrepancy in an attempt to reach a normal bite
special investigations for new orthodontic pt in clinic
- study models
- clinical photographs
- orthodontic assessment
- radiographs
- lateral cephalogram with Eastman analysis
what dental features are associated with class 3 incisor
- reduced or reverse OJ
- retroclined LI
- AOB
- anterior crossbite
- class 3 molars
- reduced OB
- crowded maxilla
tx options class 3 incisors
- accept/monitor
- interceptive tx wit URA for anterior crossbite
- growth modification with reverse twin block
- camouflage with fixed
- surgical
name components of fixed appliances
- archwire
- brackets
- molar bands
- modules
- auxillaries
- anchorage components
- force generating components [elastic power chain]
how does tooth movement work
when an external force is applied, the pDL mediates bone remodelling
in compression side the PDL space reduces, osteoclasts resorb bone and allow tooth movement
in tension side = PDl stretches, osteoblasts deposit new bone and maintain structural integrity
cell-mediated response ensures controlled tooth movement through bone resorption and formation
TENSION HAS BONE DEPOSITION, COMPRESSION HAS RESORPTION
4 methods of anchorage
- baseplate
- transpalatal arch
- nance button
- TAD [non-osseointegrating mini screw]
- elastics intermaxllary
class 2 div 2 BSI definition
lower incisors occlude posterior to cingulum plateau of upper incisors, UI retroclined, OJ minimal or slightly increased
dental features class 2 div 2
- retroclined UI
- class 2 skeletal base
- class 2 molar relationship
- deep OB, may be traumatic
- retroclined LI
- increased inter-incisal angle
- poor cingulum laterals
- short clinical crown u2’s
soft tissue features class 2 div 2
- lower lip trap
- high resting lower lip line
- trauma to gingiva/palate
- high masseteric forces
tx options class 2 div 2
- accept
- growth modification
- camouflage
- surgical
complications of ortho tx
- relapse
- decalcification
- root resoprtion
- failure to move
- gingival recession
- soft tissue trauma/ulceration
- loss of vitality
- loss of perio support
- allergic reaction
- tooth wear
how to manage
-> decalcification
-> relapse
-> root resorption
decalcification = pt education, OHI, diet advice, fluoride
relapse = pt education, long-term retention via removable/fixed retainers
root resorption = inevitable, use light forces, 2mm per month movement, pre-op assessment
BSI definition class 2 div 1
lower incisor edges occlude posterior to cingulum plateau of UI, UI proclined or average, increased OJ
class 2 div 1 dental features
- proclined UI
- increased OJ
- class 2 molar relationship
- class 2 canine relationship
class 2 div 1 soft tissue features
- incompetent lips
- lip trap
- inadequate oral seal
- special musculature posturing
tx options class 2 div 1
- accept/monitor
- simple tipping teeth
- growth modification
- camouflage
- surgery
give 4 reasons for a diastema
- supernumerary
- developmental
- hypodontia
- generalised spacing
- proclamation UI
- relapse following ortho
- trauma causing loss of tooth
- diminutive laterals
- prominent labial frenum
- unerupted central
- periodontal disease
how are diastema’s managed
- accept
- xla supernumerary
- fixed appliance
- frenectomy
- bonded retainer
design URA for posterior crossbite
A = midline palatal screw
R = Adam’s 6/4
A =
B = PBP, self-cure PMMA
give ways of expanding maxillary arch
- midline palatal screw
- quadhelix
- rapid maxillary expansion
which teeth are most commonly infra-occluded
lower D’s [8-14%]
how will infra-occluded teeth appear clinically and radiographically
- submerged, percussion sound
- blurred/absence of PDL, root resorption
tx options of infra-occluded D
- depends on presence/absence of permanent
- XLA if below IP contact
- permanent = monitor 6-12mths, may shed, XLA but need to maintain space [band + loop, extend BP URA]
- no perm = retain if good prognosis, space management or closure
define SNA, SNB, ANB
give values
SNA = position of maxilla relative to cranial base [81]
SNB = position of mandible relative to cranial base [78]
ANB = position of maxilla relative to mandible [2-4*]
what is the average FMPA angle
27*
what are the average incisor inclinations
UI - 109*
LI - 93*
what are the ANB values for class 2 + 3
class 2 = >4
class 3 = <2
explain effect of long-term digit sucking habit has on posterior dentition
creation of inward pressure leading to narrowed maxillary arch, resulting in high arched palate
due to maxillary constriction, mandible may shift laterally to achieve occlusion, creating unilateral posterior crossbite
may have mandibular displacement on closing
methods of stopping NNSH
- positive reinforcement
- habit breaking appliance
- bitter tasting nail polish
- gloves
- Elastoplast
syndromes associated with hypodontia
- Down syndrome
- ectodermal dysplasia
- crouzon syndrome
- CLP
- van der Woude syndrome
incidence of missing primary and permanent teeth
primary = 0.9%
permanent = 6%
what factors make early loss of a primary tooth worse
- no permanent successor
- age at loss [younger]
- loss of space [maxilla]
- already crowded
- tooth [e worst]
when might you consider balancing primary tooth XLA
loss of c’s
in crowded dentition
give reasons for an unerupted central incisor
- supernumerary presence
- developmental absence/hypodontia
- ankylosis of 1
- trauma damaging tooth germ
- ectopic tooth position
- pthology
- cyst
- crowding
tx options for unerupted 1
- accept/monitor
- xla primary to encourage better position and eruption
- surgical exposure with gold chain traction [closed] with space maintenance, or open
uses of URA
- tipping of teeth
- OB reduction
- maxillary expansion
- habit breaker
- space maintenance
- retract buccal canines
signs of good wear of URA
- comes in wearing
- in and out with ease
- no excess salivation
- can speak properly
- palatal signs of wear
- active component
- tooth may have moved
how is vertical skeletal relationship measured
- FMPA
- facial proportions LAFH/TAFH
how is transverse skeletal relationship measured
- symmetry = from in front and above
-any displacement on closing
- crossbite
define and give values for overjet and overbite
overjet = horizontal distance between labial surface of UI and incised edge of LI when in ICP [2-4mm]
overbite = vertical overlap of UI over LI in ICP [average 1/3 LI covered]
define and give values of molar relationships
positional relationship between U+L first molars
[average in class 1 where upper molar mesiobuccal fits into buccal groove lower molar]
define crowding and give values for extents
space or lack there of in each arch for the teeth
mild = 1-3mm
mod = 4-6mm
severe = >6mm
define incisor angulation and give values
angle at which U+L incisors are tilted in relation to maxilla/mandible
UI = 109*
LI = 93*
name 5 active components, their measurements and their uses
- palatal finger spring = retracts canines, 0.5mm HSSW + guard
- buccal canine retractors = retracts buccally placed canines, 0.5mm HSSW + 0.5mm ID tubing
- robert’s retractor 0.5mm, reduces OJ, HSSW + 0.5mm ID tubing, mesial stops 0.7mm 3’s
- z-spring = correction of anterior crossbite, 0.5mm HSSW
- midline palatal screw = expansion of maxillary arch, correction posterior crossbite
name 2 retentive components and measurements
- Adam’s clasps = 0.7mm HSSW [0.6 for primary]
- Southend clasp = 0.7mm HSSW
give 2 baseplate modifications and uses
- FABP = reduce overbite
- PBP = when using midline palatal screw, z-spring [ allows disclusion]
7y/o presents with impacted 1st permanent molars
give 5 possible tx plans
- observe [until 7y/o]
- XLA E to regain space
- disimpact with separators [band on e + 6 with open coil, dicing of e distally, URA with finger spring on 6, elastomeric separator]
- xla 6 if carious/infection/cyst
- surgical exposure 6
why might a first molar be impacted?
- angle of eruption
- ectopic crypt
- morphology of E
- small maxilla
what features of normal development should prevent crowding of permanent dentition
- growth of maxilla/mandible
- proclined permanents
- natural space between primary teeth
what is leeway space
natural space provided by retention of primary teeth
1.5mm / quadrant mandible
2.5mm / quadrant maxilla
complications of bonded retainer
accumulation of bacteria and plaque, caries, periodontal disease
can debond without knowing
if incorrect fit, can move teeth
