Orthodontics Flashcards
What is the best age for functional appliance?
- during puberty spurt
- males (12-15)
- females (9-13)
What does an orthodontic assessment include?
- C/O
2.MH (allergies, conditions , GP ) - DH (brushing , flossing , toothpaste, compliance, trauma?)
- SH (any habits , living condition, parents work, diet)
- E/O - (skeletal base palpation, vertical , transverse , LAFH , nasolabial angle, Lips , smile line , pathology)
- I/O - (teeth present, teeth quality, OH, BPE , crowding, incisor relationship , rotations, molar and canine relationship)
- IOTN (dental health and aesthetic component)
- summary ( incisor class on a skeletal class base , main issues include .. overbite , overjet, competent lips etc…)
- radiographs
What are the two causes of malocclusion?
- skeletal discrepancies
- local due to teeth (position and number)
What is the difference between unilateral and bilateral cross bites?
unilateral
mandibular displacement when cusp to cusp occlusion
**bilateral*
hemimandibular hyperplasia
Class III skeletal base
What are the local causes of malocclusion?
- teeth (number, shape and position)
- Soft tissue (tongue thhrust , digit habit , lip trap)
- pathology (cysts, caries, tumours)
What are the types of supernumerary teeth
- odontome
- conical
- tuberculate
- supplemental
What teeth do hypodontia affect the most?
upper lateral incisors
second premolars
how is the number of teeth affected in a malocclusion?
- hypodontia
-supernumerary teeth - retained primary (abscent successor, ectopic position , dilacerated)
- early primary tooth loss
- loss of permanent teeth
What conditions might affect the shape of the teeth?
- microdontia
- macrodontia
- abnormal form (peg shaped , dens in dente , accessory cusps and ridges)
What we call abnormalities in tooth position?
- ectopic
affects : 8 , 3, 6 , 1
When to extract lower 6’s
- check prognosis around the age of 8–9
- if extracted too early = distal drift of 5
- if too late = no space closure
Ideally extract at time of development of the root bifurcation of the seven
Tooth eruption dates
- 6yrs = 6s , lower central
- 7yrs = upper centrals , lower laterals
- 8 yrs = upper laterals
- 9 yrs = lower canine
- 10 yrs - 5’s and 4’s
- 11yrs = upper canines
- 12yrs - second premolars
What are andrews 6 keys of occlusion?
- tight approximal contacts with no rotations
- Class I incisors
- Class I molars
- Flat occlusal plane
- Long axis of the teeth have a slight mesial inclination except the lower incisors
- the crowns of the canines back to the molars have a lingual inclination
What are the effects of nail biting?
- misalignment of teeth (crooking)
- spacing
What are the effects of tongue thrust on a malocclusion?
- anterior open bite
- procline uppers
- relapse after treatment
What are the effects of lower lip sucking
- proclination of upper incisors
- retroclination of lower incisors
What is the effects of digit sucking?
- procline upper teeth
- retrocline lower teeth
- anterior open bite
- unilateral crossbite
How to assess vertical dimensions of the face?
- FMPA angle
- border of mandible to Frankfort plane (normal meets at occipit)
What are the contraindications of orthodontic treatment?
- nickle or latex energy
- epilepsy
- drugs such as bisphosphonates and cancer treatment, calcium channel blockers
- People undergoing MRI scans
when should digit sucking habit be stopped and why?
- age of 8-10 because roots are still developing meaning chances of spontanious repositioning is higher
- this can correct AOB
when to treat a diastema?
at the age of 12 , may close spontaneously if below 2.5mm
Treatment options for impacted 6s?
- if less than 7 years = may erupt on its own
- orthodontic separator
- Extract E
List the orthodontic guidelines
- british orthodontic society : managing the developing occlusion
- british orthodontic society : referral guidelines for orthodontic treatment
- RCS : management of unerupted maxillary incisors
- RCS : management of palatally ectopic canines
- BSI incisor classifications
Describe the growth of the upper ectopic canine
starts developing very high and palatally , then migrate labially and distal to lateral incisors
When do we palpate for canines?
- at the age of 9-11
- X ray at 11 years
What are the treatment options for an ectopic canine?
XLA of c’s (wait for spontaneous repositioning)
- orthodontic traction with gold chain (open or closed exposure)
What are the risks of no treatment to ectopic canine?
- missing teeth
- pain
- it will become more ectopic
- may cause root resorption of adjacent teeth
How do you structure orthodontic treatment planning?
- plan around lower arch as angulation is most suitable
- build upper arch around lower
- aim for class I incisor and canine relationship
- decide on molar relationship ( can accept class 1 or class 2 )
What are the two theories explaining why teeth move in orthodontics?
differential pressure theory
(when force applied , bone laid on tension side and resorbed in pressure side)
** Mechano-chemical theory**
(mechanical loading causes cell shape changes in the osteoblasts this causes the release of signalling chemicals that stimulate bone remodelling
What are the kinds of orthodontic movements
- Tipping
- Bodily movements
- intrusion
- extrusion
- rotation
- torque
At what age do functional appliances become useless? and for how long do you wear them for?
- at the age of 14 as the pt stops growing
- 6-12 months
What is secondary remodelling?
- when pressure is applied to a tooth causes bone deposition on the other side of the alveolar bone
What is dentoalveolar compensation?
a system which can attain and maintain a normal relation with varying skeletal patterns through the eruption of teeth when there is skeletal changes
What is the aetiology for skeletal class III?
- genetics (small maxilla or large mandible)
- Acromegaly
- cleft lip and palate
What are the growth modification options for class III skeletal ?
- chin up
- reverse twin block
- frankel III - soft tissue born version
- TAD’s
What treatment options for skeletal Class II
- growth modification during growth
- Camouflage (accept underlying skeletal base)
- only if mild skeletal discrepancy
- make teeth in class I relationship
- extractions - remove from further back in ipper and more mesial in lower
- Orthognathic surgery
Define Class II div 1 incisor relationship ?
- lower incisal edges occlude posterior to upper cingulum
- with increased overjet
- upper incisors can be proclined or of average inclincation
Why treat class II div 1
- asethetics
- function
- avoid trauma
What is the aetiology of class II div 1?
- Class II skeletal pattern
- retrognathic mandible
- OJ = inclinded uppers and skeletal pattern
What are the soft tissue issues associated with class II div 1 ?
- common to have incompetent lips
- lip trap
What dental factors are associated with class II div 1?
- increased overjet
- overbite
- dry mouth leading to caries and gingivitis
What are the management options for class II div 1 ?
- accept and monitor
- teeth tipping : URA
- fixed appliance
- growth modification (tooth born, twinblock , frankel II)
- orthognathic surgery
what is the negative effects of early growth modification?
- skeletal effects not maintained long term
- 2 stages of treatment are required
- literature shows no difference to waiting until full dentition
What are the benfits of full adult dentition growth?
- better aesthetics
- lower risks of trauma
- better compliance
Define class II div 1
- lower incisal edge occlude posterior to cingulum of upper incisors with the retroclined upper incisors
What is the aetiology of class II div 2 ?
- skeletal class II
- soft tissues (lower lip retroclines upper incisors)
- crowding
- pathology
What are the signs of Class 2 div 2?
reduced FMPA
Describe the soft tissue aetiology of class II div 2 ?
- linked with reduced FMPA and lower LAFH
- lower lips acts on upper central incisors as it is positioned higher
- can procline lateral incisors as they get trapped on the lower lip
- high smile line
- marked labiomental fold
- high masseteric forces
What is the standard radiograph for ortho assessment?
- lateral cephalograms
- eastman analysis is the analysis of cephalogram
- it views the relationship between the jaws, the jaw and the cranial base, the position of the teeth compared to the jaws the soft tissue profile
- relationship of the jaw to the base of the skull
What are the average values of SNA and SNB and ANB?
SNA - 81 -/+ 3
SNB - 78 -/+ 3
ANB - 3 -/+ 2
Severity of skeletal classes based on ANB?
Class II
mild = 4-6
moderate = 6-8
severe = >8
Class III
mild = 0-2
moderate = 0- -3
severe = >-3
When is the best age to extract 6s?
8.5 - 9.5 yrs
What is a compensating extraction?
extracting same tooth in one side in both arches ( this is to preserve the occlusion and do avoid over eruption of tooth on other arch)
What is balancing extraction?
removal of the same tooth in the same arch
- this can be to preserve symmetry
- first permanent molar extraction no effect on shifting the midline
What may be some advantages that a functional appliance may do ?
- encourage favourable skeletal growth
- correct molar relationship
- correct the angulation of the upper incisors
What are the extraction factors to think about when extracting a first permanent molar?
–stage of dental development
-other missing teeth
-patient and parent motivation
- skeletal pattern
- malocclusion type
- degree of crowding
What are the options available for maintaining teeth that are compromised?
- GI until extraction
- composite restorations
- preformed crowns - to buy time or to be replaced once in full dentition
- onlays - gold or composite
how can you carry out an extra oral examination?
- Skeletal bases ( A-P, vertical , transverse)
- check TMJ
- check lymph nodes
-look for asymmetry - look for lips if competent or no , lip trap?
- Smile line
- Nasolabial angle
How to carry out an intro oral examination?(ectopic canine )
- palpate for canines (palatal and bucca
- check mobility of retained C’s and lateral incisors
- check all soft tissues
- chart teeth (present, quality )
- assess OH
- look for any toothwear
- check periodontal health
- look for crowding (mild , moderate or severe)
- any toothwear
- check overjet
- check overbite
What radiographic technique do we use to locate ectopic canine position?
OPT + occlusal maxilla
using parallax technique and figure out the position of ectopic canines (SLOB - same lingual opposite buccal)
What is the incidence of ectopic canines?
1.5%
What is the aetiology of ectopic canines?
- genetics
- could be due to long path of eruption -> delayed eruption
- can be associated with hypodontia or lateral peg shaped incisors
- crowding resulting in insuffucuent space
What to check to assess IOTN?
Missing
overjet
crowding
displacement
overbite
What are the risks of doing nothing in an ectopic canine case?
root resorption of other teeth if canine moves
may make future treatment more difficult
crown may resorp other teeth
Ankylosis of canine
Aesthetics
How would you carry out surgical exposure of canine?
surgical exposure and orthodontic traction
Expose canine using open or closed exposure technique (depends on canine position) - then apply gold chain orthdodontic traction to align canine within arch
What is open exposure?
- a window of tisue around the tooth is removed and pack placed with sutures to prevent healing
What is closed exposure?
attachment with chain is bonded to canine an flap is sutured back with chain penetrating the mucosa
Describe the option of autotransplantation in managing ectopic canines
- not very good for canines
it requires no ankylosis and at least 3/4 of root development
What are the risks associated with autotransplantation?
- need careful surgical technique
- pain
- pt compliance
- infection
- bleeding
- needs MDT
What are the most commonly teeth affected by hypodontia?
- third molars
- mandibular second premolar
Advantages of accepting space?
- spaced dentition is more likely to maintain long term
- occlusion is adequate to maintain goof masticatory function
Disadvantages of leaving space?
- patient aesthetic dissatisfaction
- drifting of other teeth may occur making future treatment more difficult
What warnings to give patient after consenting for replacing teeth with prosthesis?
- lifelong maintenance of prosthesis
- potential failure of prosthesis
- slight increase in caries risk for bridge abutement teeth
- patient willingness to undergo complicated implant treatment
- moderately good long term success of bridgework
Why not close incisor space?
- very difficult to close large spaces in an area where alveolar bone width is likely to be compromised
- Smile aesthetics likely to be poor
- overbite likely to deepen and become traumatic
- high chance of relapse
What risks should patient be warned about in orthodontic treatment?
- increased caries rate (decalcification)
- root resroption
- relapse
- high level of commitment is required for wearing a twinblock
- Ability to achieve best outcome depends on patient compliance
- long term maintenance is required
What are the survival rates of resin retained bridge
- five year 80.8
- 10 years 80.4
What is the prevalence of hypodontia?
7%
What does interceptive orthodontic treatment involve?
- the utilisation of tooth eruption to minimise the impact of a developing malocclusion
- extracting decidious teeth at correct stage to encourage permanent teeth to erupt
When is the correct stage for exctracting decidious teeth to encourage permanent tooth eruption
when one half to two thirds root development of permanent tooth
where do the permanent incisors develop in relation to the primary incisors?
- palatal / lingually
additional space is required to accommodate the larger anterior teeth of the permanent dentition, how is this space gained?
- increase in the intercanine width through lateral growth of jaws
- the leeway space
what is the leeway space in upper arch?
1-1.5mm
What is the leeway space in of the lower arch?
2-2.5mm
What size of diastema closes on its own?
less than 2.5mm
How would you treat a patient with imapction of the first permanent molar?
- if patient under 7 , wait 6 months , usually it will erupt spontaneously
- place orthodontic separator
- attempt to distalise the first molar
- Extract E’s
What can early loss of deciduous teeth lead to?
localised crowding
A patient has loss of As and Bs , what is the treatment options?
- little impact
- do nothing
- permanents will erpt
Patient has early loss of C , what to do?
balancing extractions
A patient loss of E’s , what is your treatment?
- tend not to balance
- major space loss
- consider space maintainer
what might early loss of LRe lead to?
mesial drift of LR6
Types of space maintainers
fixed and removable
When is extraction of first molars most ideal?
- 7s bifurcation calcification
- 8s are present
- class 1 av/reduced OB
- moderate lower crowding
- mild to moderate upper crowding
if you extract a lower 6 what must you also do?
extract upper 6
How can a child with digit sucking habit be managed?
positive reinforcement
bitter tasting nail varnish
glove on hand, elastoplast
habit breaker appliance
How to tell if the patient wears their appliance?
- walk in surgery wearing it
- they can speak wih it
- see if they have excess salivation
- if they can take it out easily
- any signs of wear on appliance
- tooth movement
At what age should digit habit be stopped?and ehy treat it?
<9 yrs , to encourage spontaneous correction of anterior open bite , to prevent worsening the malocclusion with growth (skeletal development)
What appliances can be used for digit habits?
- one piece basplate with single goal post
- Split baseplate with expansion screw and 2x palatal goal posts
- bluegrass appliaince
What is the aetiology of infraoccluding teeth?
through ankylosis of primary tooth and the surrounding alveolar bone continues to grow , may be due to trauma or genetics
How can infra-occlusion of teeth be diagnosed?
percussion
check for mobility
radiographs
what to look on radiograph for an infraoccluded tooth?
presence or absence of successor
ankylosis of primary tooth
root resorption of primary tooth
How should infra-occlusion of a tooth be treated when the permanent successor is present?
- monitor for 6-12 months
- extract if below interproximal contact
- consider extraction if root formation of succesor is near completion
- maintain space when extracting
What are the risks of doing nothing to an infraoccluded tooth?
- permanent successor can become more ectopic
- tipping of adjacent teeth (leads to hard extraction as cannot access infraoccluded tooth)
- caries and periodontal disease
What to do if you cannot palpate canine by the age of 11?
take a radiograph
How to intercept ectopic teeth?
consider extraction of c
when will an extraction of the c be a successful treatment option for ectopic teeth?
- patient between 10-13 years
- canine is distal to midline of upper lateral incisor
- sufficient space is available
What are the risks of doing nothing about an ectopic maxillary canine?
- can become more ectopic
- fails to erupt
- risk of root resorption to adjacent teeth
- risk of root resorption of canine crown
- risk of cyst
- risk of ankylosis
What interceptive treatment can be done for class III malocclusion?
growth modification
- enhance maxillary growth , reduce mandibular growth
- protraction headgear and rapid maxillary expansion
- patient needs to wear it 14 hours a day
- fixed appliance with URA
When will growth modification for class III be most successful?
- mild class III
- maxillary retrusion
- anterior displacement on closing
- average or reduced lower face height
-patient aged from 8-10
What are the risks associated with increased overjet?
- risk of trauma
- appearance
- more difficult to achieve correction once patient has stopped growing
What is IOTN?
Index of Orthodontic Treatment Needed (IOTN) is a scale designed to measure the orthodontic need of a patient. It has two components:
The Dental Health Component (DHC)
The Aesthetic Component (AC)
The Dental Health Component (DHC) scale (1 to 5):
1 = no need
2 = little need
3 = borderline need
4 = need
5 = very great need
The Aesthetic Component (AC) scale (1 to 10):
1 to 4 = little or no need
5 to 7 = borderline need
8 to 10 = great need
What is an overjet ?
It is the extent of horizontal (A-P) overlap of the maxillary central incisors over the mandibular central incisors - average 2-4mm , measured using ruler held parallel to occlusal plane when teeth are in ICP
What is an overbite?
It is the extent of vertical (superior inferior) overlap of the maxillary central incisors over the mandibular central incisors measured relative to incisal edges - average 1/2 to 1/rd , measured using a ruler held held parallel to occlusal plane and can be classed as average, increased or decreased
