Orthdontics Flashcards
What are the possible complications for a patient with 12mm OJ, well aligned arches and ectopic canines?
Trauma
Root resorption of adjacent 2s
Difficulty eating
Difficulty speaking
What are the potential complications of a dental retainer?
Calculus build up- higher risk of gingivitis and Periodontal disease
Caries- difficulty cleaning
Wire can debond
Wire can fracture
What are the components for correcting a posterior cross bite?
Aim- Please construct a URA to fix posterior xbite
A- Midline palatal screw
R- Adams clasps 0.7mm HSSW 4s/6s
A- reciprocal
B- Self cure PMMA with PBP
What is Deviation of the mandible on closing?
Mandible displaces in order for teeth to come into occlusion on closing
What are 2 problems that can occur if mandibular deviation goes untreated?
TMD
Tooth wear
Which fluoride supplements can be given to patients to prevent decalcification in Orthodontics?
FV- 22600ppmF (4 x yearly)
Fluoride mouthwash- 225ppmF (daily)
Duraphat toothpaste- 2800 ppmF (twice daily)
Fluoride tablet- 1mg per day
What are the other ways in which decalfication can be prevented?
Good OH
-> Interbracket cleaning after meals
-> Focusing on gingival margin and around bracket when brushing
Improve diet- limit sugar frequency
Chewing gum
FS
What are the risks of Orthodontic treatment?
Relapse
Recession
Root resorption
Soft tissue trauma
Enamel fracture
Tooth wear
Loss of vitality
Headgear injuries
Poor or failed tx
How would you assess the AP relationship of a class 3 malocclusion?
Palpate the skeletal bases at soft tissue A and soft tissue B
Lateral Ceph
Visual assessment
What special investigations may an orthodontist do for a patient worried about their Class 3 relationship?
Study models
Clinical photographs
Lateral ceph
OPT
What are the intra-oral features typical of class 3 relationship?
Retroclined lower incisors
Proclined upper incisors
AOB
Reversed or reduced OJ
Displacement on closure
What systemic condition may a patient have if their mandible is growing in adulthood?
Acromegaly
Design a URA to fix anterior Crossbite of 12?
Aim- please construct a URA to fix cross bite on 12
A- Z spring 0.5 HSSW on 12
R- Adam’s clasps 0.7 HSSW on 4s/6s
A- Yes as moving one tooth
B- Selfcure PMMA with PBP
What characteristics of the dentition would make fixing an anterior crossbite with a URA?
What 5 factors can cause displacement of a URA?
Gravity
Mastication
Active component
Speech
Tongue
When referring a patient to an orthodontist, what information relevant to their provision of care should be provided?
Patient details- age and name
Medical Hx
Radiographs and photographs
Skeletal base
Incisor classification
A patient undergoing orthodontic treatment, attends for a check up with debonded bracket and demineralisation around the remaining brackets. How is this managed?
Debonded bracket
-> remove and give to the patient
-> Give OHI and refer to orthodontist
Demineralisation around remaining brackets
-> OHI
-> Diet advice
-> Fluoride supplementation
What are the long term risks of lost upper 1?
Poor aesthetics
Bone resorption
Loss of labial profile
Drifting of other incisors
What are the long term risks of using a provisional upper RPD to replace an upper 1?
Why would you advise a patient against a crown to replace their upper 1?
Destructive treatment
OH must be adequate to place a crown
What advice would you give to a non-compliant patient to maintain their oral health long term?
Brush 2x daily with F tooth paste
Spit don’t rinse
Use modified bass technique
HIGH risk- so duraphat 5000ppmF could be offered
Interdental cleaning- floss or ID brushes
What are the uses of a URA?
Tipping teeth
Habit breaker
Anchorage
Expand arch
Reduce OB
Space maintainer
What advice is given upon fitting of a URA?
- Will feel bulky- normal
- May have excess salivation- goes away in 24 hours
- May affect speech- practise reading aloud
- May cause initial discomfort- indicates its working
- Wear 24/7- non-compliance increases tx time
- Remove after every meal and clean with soft brush
- Remove when playing contact sports
- Avoid hard/sticky and overly hot foods
What are the steps in delivering a URA?
- Check right patient- right appliance
- Check appliance matches design specification
- Inspect appliance for sharp areas
- Check integrity of wirework
- Insert into mouth- check for areas of blanching or trauma
- Check posterior retention
- Check anterior retention
- Activate appliance
- Demonstrate correct insertion/removal
When is the best time to treat an anterior crossbite?
When upper 2s erupt
What features make a URA useful at fixing crossbites?
PBP
What is the incidence of hypodontia in the UK?
6%
What 3 teeth are most commonly missing in hypodontia patients?
Lower 5s
Upper 2s
Upper 5s
How does hypodontia present to the GDP?
Big midline diastema
Infraocclusion
Teeth not erupting/exfoliating in expected sequence
Tapered and small teeth
Absence of deciduous tooth
What are the treatment options for hypodontia?
Accept/montior
Restorative only- bridges, implants, dentures
Ortho only
Combine orthodontic and restorative- open space/close space
Who are the members of the MDT that treat hypodontia?
Ortho specialist
Restorative dentist
Paediatric dentist
GDP
SLT
OS
When should you start to palpate for canines?
Age 9
How is position of canines localised?
Vertical parallax
What radiographs are used for vertical parallax?
OPT and occlusal
What age should intervention for ectopic canines be carried out?
Age 11
How long after extraction of C should we review an ectopic canine to check for eruption?
6 months
What are the treatment options for an ectopic canine when the C has already been extracted?
Buccal apically repositioned flap with bone removal
Palatal open exposure with bone removal
Buccal or palatal closed exposure with gold chain attachment
Extraction of 3
What is a supernumerary tooth?
Presence of an extra tooth
Where is a supernumerary most likely to occur?
Midline of maxilla
What are the 4 types of supernumerary, how are they distinguished?
Conical- cone shaped
Tuberculate- barrel shaped
Supplemental- extra tooth of normal dentition (usually smaller and asymmetrical)
Odontome- irregular mass of dental hard tissue
-> Compound and Complex
What is the effect of supernumeraries on the dentition?
Delayed eruption
Crowding
Failure of teeth to erupt
Traumatic eruption
What are the signs of thumb sucking habit?
Proclined upper anterior
Retroclined lower anteriors
AOB/incomplete open bite
Narrow upper arch (may have unilateral posterior xbite)
What is the BSI definition of Class 2 Div 1
The lower incisor edges lie posterior to the cingulum plateau of the upper incisors
-> There is an increased overjet
-> The upper central incisors are proclined or of average inclination
What are the ways in which functional appliance can reduce OJ?
Growth modification
-> Restricts growth in maxilla, promotes growth in mandible
Mandible postured away from normal rest position
-> facial musculature is stretched generating forces transmitted to teeth/alveolus
Dentoalveolar compensation
-> Reclines upper incisors
-> Proclines lower incisors
-> Mesial migration of lowers, distal migration of uppers
What are the signs of impacted canines?
Retained Cs
Delayed eruption
Asymmetrical eruption
Distal tipping of 2s
Discolouration of 2s
Mobility of 2s
How can you further investigate impacted canines?
Vertical/horizontal parallax
ICAT scan on CBCT
What are the risk of ectopic canines?
Root resorption of 2s
Cyst formation
Ankylosis of deciduous tooth
Aesthetic issues- spaces
What are the treatment options for ectopic canines
Accept/monitor
Extract C to encourage improvement in position
Retain 3 and observe
Extraction
Surgical exposure and orthodontic alignment
Autotransplantation
What is the incidence of CLP?
1:700 live births
What are the general health implications of CLP?
Aesthetic issues
Speech issues- issues with plosive sounds
Dental issues
Hearing/airway issues- more likely to suffer glue ear and ears may not properly form
Other- more likely to have cardiac abnormality
What are the dental features of CLP?
Missing teeth
Impacted teeth
Crowding
Caries- hypoplastic
Class 3 jaw relationship
What are the 5 treatment stages for fixing a CLP?
3 months- lip closure
1 year- palate closure
-> done before baby starts to talk/babble to ensure palate is as normal as possible for this
8-10 year- alveolar bone graft
12-15 years- definitive orthodontics
18-20 years- Surgery (secondary)
Who are the members of the CLP MDT?
Surgeons
Cleft nurses
Paediatric dentist
Psychologist
ENT doctor
Speech therapist
Geneticist
What is a class III incisor relationship?
Lower incisor edge occludes anterior to the cingulum plateau of the upper central incisor
-> overjet is reduced or reversed
What is dentoalveolar compensation?
Soft tissues and teeth are in altered position to compensate for skeletal discrepancy and achieve normal relationship between upper and lowers
Which special investigations may be useful when treating patients with Class III jaw relationships?
Clinical photos
Study models
Lateral ceph
CBCT
OPT
What dental features are associated with Class 3 relationships?
Proclined upper incisors
Retroclined Lower incisors
Crossbites- anterior
Attrition
Recession
Crowding
What are the treatment options for a Class 3 patient?
Accept and monitor
Intercept with early URA to correct incisor relationship/crossbites
Growth modification- reverse twin-block/headgear
Camouflage- accept skeletal base and aim for class I incisors with fixed appliance
Combined orthodontic/orthognathic
What are the components of fixed appliances?
Brackets
Arch wire
Ligatures
Elastic modules
Auxiliaries- springs, elastomeric chains
Anchorage components
Molar bands
Give 4 methods of anchorage?
TAD
Baseplate
Transpalatal arch wire
Elastics
What is the definition of Class 2 Division 2?
Lower incisors occlude posterior to the cingulum plateau of upper central
-> Upper centrals are retroclined
-> OJ may be reduced or increased
What are the dental features of Class 2 div 2?
Retroclined upper centrals
Increased OB
Shorter arch perimeter- more crowding
Reduced OJ- usually
Crowded upper 2s- mesiolabially rotated
What are the soft tissue features associated with C2D2?
Marked labio-mental fold- overactive mentalis
High Lower lip line- can retrocline upper incisors
High masseteric force
Trauma to gingivae or palate due to increased OB
What are the treatment options for C2D2?
Accept and monitor
Growth modification- twin block with ELSA spring
Camouflage- accept underlying skeletal base and give class 1 incisors
Orthognathic surgery if severe
What are the common complications of orthodontics?
Relapse
Root resorption
Decalcification
Gingival recession
How are complications of orthodontics managed
Relapse- lifelong retention (fixed or removable)
Decalficiation- OHI, F supplementation diet advice
Root resorption- advise patient of risk, advise that 1mm resorption is normal over 24 month tx, stop nail biting habit, be careful with unusual root forms
Recession- avoid over expansion, warn patient, consider gingival grafting
What are the dental features of class 2 div 1?
Proclined upper anteriors
Increased OJ
Hyperplastic gingivitis
Varied OB
Class 2 molar relationship
What are the soft tissue features of Class 2 div 1?
Lip trap
Incompetent lips
Tongue thrust
What are the treatment options for class 2 div 1?
- Accept
- Attempt growth modification- twin block/head gear
- URA- Simple tipping of teeth
- Camouflage- used fixed appliance to achieve class 1 incisors while accepting skeletal base
- Orthognathic surgery
What are the causes of diastema?
Prominent frenal attachment
Ectopic canines
Hypodontia
Supernumeraries at midline
Microdontia
How are Diastemas managed
How is posterior cross bite managed?
URA with midline palatal screw and PBP
What are the other means of expanding the arch?
Quad-helix
Rapid maxillary expansion
What teeth are most commonly infra-occluded
Lower Ds
How do infra-occluded teeth appear clinically/radiographically?
C:
Low in the arch- doesn’t maintain occlusal relationship with adjacent teeth, non-mobile, percussion sound
R:
External root resorption
No PDL
What are the treatment options for infra-occluded molars?
Retain if no permanent successor
Monitor for up to a year if permenant successor
Extract tooth
-> if contact points go sub gingival
-> if root formation of successor is near completion
-> early to encourage space closure if crowding
What is SNA, SNB, ANB?
SNA- Angle between Sella-nasion line (cranial base) and
maxilla at point A
SNB- Angle between SN line and mandible at point B
ANB- difference is angle of SNA and ANB
What are the average values of SNA, SNB, ANB?
SNA- 81 (+/-3)
SNB- 78 (+/-3)
ANB- 3 (+/-2)
What is the average FPMA angle?
27 (+/-4)
What is the average incisor inclination?
109 in upper
93 in lower
What is the ANB for class 2 and 3?
Class 2- ANB >5
Class 3- ANB <1 or negative
What is the effect of prolonged sucking habit on the posterior dentition?
Sucking action pulls cheeks in causing narrowing of maxillary arch (mandible is out of way due to position of thumb)
-> this can cause a posterior cross bite
What are the methods of stopping a thumb sucking habit?
Fixed habit breaker
Removable habit breaker
Positive reinforcement
Preventive nail varnish
Swap for a dummy- unlikely to continue past school age
What are the syndromes associated with Hypodontia?
CLP
Anhydrotic ectodermal dysplasia
Down’s
What is the incidence of hypodontia in primary and permanent dentition?
Primary- 1%
Secondary- 6%
What are the affects of supernumerary teeth?
Cyst formation
Associated with diastema
Crowding
What factors can make early loss of primary teeth worse?
Crowding
Lack of permanent successor
Maxilla is worse
Younger age
What is balancing and compensating?
Balancing- taking out contra-lateral
Compensating- if lost in upper, remove lower
When might you consider balancing a primary tooth extraction?
Balancing Cs to prevent midline shift
When would you consider a compensating extraction?
If lower 6s extracted- compensate with upper
-> prevents over eruption and mesial movement of 7
What are the signs of a good wearer of a URA?
Active components have become passive
Patient demonstrates correct insertion and removal
Patient can speak normally with URA in
Tooth movement has occurred
Patient arrives wearing URA
Signs of wear on palate and appliance
What are the different anterior-posterior skeletal relationships?
Class 1- maxilla is 2-3mm anterior to mandible
Class 2- maxilla is >2-3mm anterior to mandible
Class 3- mandible anterior to maxilla
How is vertical relationship measured?
Face height:
Visual- lower anterior face height to total face height is 50:50
Lateral ceph- LAFH:TAFH is 55%
FMPA:
Visual- maxillary and Frankfort planes meet at occiput
Ceph- angle of 27 (+/4) is average
How is transverse relationship measured?
Look at symmetry from front and above
What is OJ and the average value?
Gap between the labial most prominent surface of the lower incisors and labial most prominent surface of upper incisors
What is OB? What is average?
Vertical overlap of incisors
- Uppers cover 1/2 to 1/3 of lower incisors
What is a class 1 molar relationship?
MB cusp if upper 6 occludes with buccal groove of lower 6
2- anterior
3- posterior
What is class 1 canine relationship?
Maxillary canine occludes between mandibular canine and first premolar
2- Anterior
3- Posterior
How is crowding measured?
Overlap technique
Space available (between mesial of 6s)- space required (width of every tooth from 5-5)
-> done using callipers on models
What is mild/moderate/severe crowding ?
Mild 0-4mm
Moderate 4-8mm
Severe 8+mm
What are the active components used in URAs?
0.5 HSSW:
Finger spring and guard- retracting canines
Z spring- fixing anterior crossbites
Flapper spring
T spring
0.5 HSSW w 0.5 ID tubing:
Buccal canine retractor
Roberts retractor- incisor
Midpalatal screw- expanding upper arch
What are examples of retentive components?
Adams clasp (0.6 if primary)
Southend clasp
Labial bow
ALL 0.7 HSSW
What are examples of baseplate modifications?
FABP- allows eruption of posteriors to allow for OB correction (OJ +3mm)
PBP- allows posterior disclusion allowing anterior movement/eruption
What are the treatment options for impacted molars?
Accept/monitor
Extract E to encourage eruption
Use separator
XLA and retain E
Distalise 6 with a URA
What are the cause of first molar impaction?
Crowding
Hypoplastic maxilla
Mesial path of eruption
What feature of normal development should prevent crowding of permanent dentition?
Spacing between teeth
Growth of maxilla and mandible
What is Leeway space?
Extra mesio-distal space occupied by primary molars which are wider than premolar replacements
-> 1.5mm per side in upper
-> 2.5mm per side in lower
