Orthodontics Flashcards
What does “ortho” mean?
Greek word meaning straight or upright
What does dontics mean?
Teeth
What does orthodontics do?
The development, prevention and correction of irregularities of the teeth, bite and jaw
Examples of when orthodontics is used?
- Interceptive
- Ectopic / impacted teeth
- Hypodontia
- Cleft, lip and palate
- Craniofacial disharmony
- Misaligned teeth
What needs to be considered when thinking of orthodontic treatment?
Risk VS Benefit
What is the role of a dental therapist in terms of orthodontics?
Gatekeepers of orthodontic treatment and it is crucial that they can identity the patient’s occlusion problem and refer
What are we listening for when examining a patient for orthodontic treatment?
- Patient concerns
- Family concerns
- Social concerns
What are we looking for in terms of teeth when considering ortho treatment?
- Missing teeth
- Teeth of poor prognosis
- Tooth positioning
- Traumatic occlusion
What are we looking for in terms of soft tissues when considering ortho treatment?
- Lip trap
- Gingival recessiom
What are we looking for in terms of facial bones when considering ortho treatment?
- What is the jaw relationship
- Are the jaws symmetrical
What is the most important thing that needs to be good for a referral to ortho?
Oral hygiene
What happens during an orthodontic examination?
- Listen to concerns
- Assess facial skeleton
- Assess gingival health
- Assess oral hygiene
- Assess teeth
How to measure skeleton pattern?
- Upright natural head position
- 90 degrees in dental chair
- Resting position
What are the 3 planes in which Skelton patters should be measured?
- Anteroposterior
- Vertical
- Transverse
How to measure anteroposterior?
- View patient from the side
- Look at the relative position of maxilla and the mandible
- Palpate tissue A and B point
What is a class 1 pattern?
Mandible is in 2-3mm posterior to maxilla (normal)
What is class 2 pattern?
Mandible is retruded relative to the maxilla (underbite)
What is class 3 pattern?
Mandible is protruded relative to the maxilla (overbite)
What are the 2 assessments for vertical plane?
- Lower facial height
- Frankfort mandibular plane angle
What is the lower facial height?
Distance from the eyebrow to the base of the nose should be equal the distance from the base of the nose to the lowermost point of chin
What is the frankfort mandibular plane angle?
Point of intersection between the mandibular plane and frankfort plane - intercept at occiput
What are vertical measurements classed as?
- Average
- Increased
- Reduced
How to measure transverse pattern?
- View from above and the front
- Tongue spatula
What radiographs are used for ortho treatment?
- DPT
- Lateral Ceph
- Upper anterior occlusal
- CBCT scan
What should you consider medically when referring for ortho?
Treatment choice
Gingivae
Extraction haemophilia
Co operation
Infection risk - diabetes
Candida risk - asthma
What in the social history would you consider when referring for ortho?
Motivation
Habits - thumb sucking
Hobbies - contact sport
Attendance
What is IOTN?
Does the patient qualify for treatment on the NHS
What does IOTN stand for?
The index of orthodontic treatment need
What are the two elements of IOTN?
Dental health
Aesthetic
What score does dental health need to be for NHS treatment?
4 or 5
What is the dental health based on?
worst feature of malocclusion
What does MOCDO stand for?
Missing teeth
Overjet
Crossbites
Displacement of contact points
Overbites
How is aesthetics measured?
10 standard colour photographs
What is classed as a normal occlusion?
All teeth well aligned
No crowding
Class 1 incisor relationship
Class 1 molar relationship
What is malocclusion?
An irregularity in the occlusion beyond the accepted range of normal
Causes of malocclusion?
Skeletal pattern
Size of jaw and teeth
Syndromes
What causes crowding?
Big teeth
Small jaws
What causes spacing?
Small teeth
Big jaws
What is a removable appliance?
Not attached to the teeth and can be removed for cleaning and sports
What are the components of conventional removable appliances?
BARA
B - baseplate
A - active component
R - Retentive component
A - Anchorage
What are active components?
Springs - Z springs
Screws - Midpalatal screw
Bows - Labial bows
What is the force produced by the component dependent on?
Length of wire
Radius of wire
Elastic modulus (stiffness)
Size 0.7mm spring requires what activation?
1mm
Size 0.5mm spring requires what activation?
3mm
What degrees does a palatal finger spring require?
90 degrees
What degrees does a z spring need for movement?
45 degrees
What are retentive factors?
Southend clasp
Adams clasp
Delta clasp
Ball ended clasp
What is a baseplate?
Acrylic
Holds components together
Can incorporate bite planes
Provides anchorage for the appliance
What is anchorage?
Resistance to unwanted tooth movements
Advantages of removable appliances?
Can be removed for cleaning and sport
Good anchorage
Can move blocks of teeth
Cheap
Less chairside time
Easy to adjust
Disadvantages of removal appliance?
Temp affect on speech
No bodily tooth movement
Retention post correction difficult
Requires good technical support
What is a removable appliance used for?
Anterior cross bite
What is a functional appliance?
Alter the muscle forces against the teeth and craniofacial skeleton
What are functional appliances used for?
Class 2
What is a fixed functional appliance?
The energy is stored within the appliance and forces are applied to teeth, soft tissue and bone
What is a removable functional appliance?
The energy is stored within the muscle and ligament
What’s an example of fixed functional appliance?
Herbst appliance
What’s an example of removable functional appliance?
Twinblock
Advantages of twin block?
Good for dental health
May avoid extractions
May accelerate growth
May reduce trauma
Disadvantages of twin block?
Bulky appliance
Herbst known to fracture
Can affect speech
Cause soft tissue trauma
Lack of detailed tooth movement
What to expect after functional appliance?
Overjet of 2mm
Edge to edge malocclusion
Partial success
Why do functional appliances fail?
Not worn enough
Not been made properly
Wrong treatment (adverse growth changes)
What is a fixed appliance?
Attached to the teeth by bands or bonds and brackets
How does a fixed appliance move the teeth?
Using a wire and it’s interaction with the brackets and bands
What 2 wires are used in fixed appliance?
Nickel titanium
Stainless steel
What 2 sizes are orthodontic wires?
Round
Rectangular
What are the 5 types of tooth movement?
Tipping
Bodily movement
Extrusion and intrusion
Rotation
Torque
What appliance will cause tipping?
Removable and fixed
What appliance will cause bodily movement?
Fixed only
What appliance will cause extrusion and intrusion?
Removable and fixed
What appliance will cause rotation?
Fixed only
What appliance will cause torque?
Fixed only
Risks of fixed appliance?
Caries
Gingivitis
Periodontal destruction
Soft tissue trauma
Pulpal necrosis
Root resorption
Recession
Advantages of fixed appliance?
Full range of tooth movement
What types of fixed appliances is there?
Labial + Lingual
TPA
Quad helix
RME
Mini screws
What are the 2 phases of ortho treatment
Active treatment
Retention phase
What is the biggest risk of all ortho treatment
Relapse
What is the current advice for retainers
Worn 7 nights a week
Worn for life
What are the 2 main types of removable retainer
Hawley retainer
Clear plastic
What is good about the hawley
Can add a pontic
What are the 3 types of fixed retainer?
Twist - Flex
Ortho - Flex
Memotain
As a therapist we might have situations of ortho emergencies, if someone has a problem with removable appliance what should we do?
URA - Refer
Functional - Refer
Retainer - make in house
As a therapist we might have situations of ortho emergencies, if someone has a problem with fixed appliance what should we do?
Bracket off - Refer
Band loose - Refer
Wire out causing trauma - Can cut
What are some abnormalities that ortho can fix?
Crown root dilaceration
Supernumerary
Peg shaped incisors
Hypodontia
What is crown root dilaceration?
Trauma causes displacement of un erupted permanent teeth and causes the crown and root to form in another direction
Where does crown tooth dilaceration occur?
Any point of the root
What do peg shaped incisors increase the risk of?
ectopic canine
What is neonatal teeth?
Primary teeth that have already erupted at birth and can cause feeding problems
What is the treatment for neonatal teeth?
If very mobile then extract however if in situ then leave as is
What is an eruption cyst?
Appears as a blue mucosa overlying an unerupred tooth
Where is it common to see an eruption cyst?
Over the Es and 6s
What symptoms does an eruption cyst have?
They are asymptomatic
What’s the treatment for an eruption cyst?
Resolves on its own when the tooth erupts
What are impacted teeth?
When primary or permanent teeth do not erupt fully, can be partially erupted
What caused impacted teeth?
An obstruction
What is infra occluded and retained teeth?
Causes by ankylosis adjacent teeth erupt and and ankyloses teeth remained unchanged
What is the treatment for infra occluded or retained teeth?
Usually extraction but if missing permanent successor then leave in situ
What 3 things most commonly cause premature loss of primary teeth?
Caries
Balancing and compensating
Serial extractions
Where is most commonly affected by caries in primary teeth?
Mesial drifting of the 6s resulting in premolar crowding
How does trauma affect the developing dentition?
Avulsion of incisors can cause a midline shift
Delayed eruption of permanent successor
Intrusion of incisors can causing deflection in permanent successor
What teeth are most likely to cause an affect with balancing extractions?
Cs and Ds
What are serial extractions?
Kjellgren 1948 – planned sequence of extractions to relieve incisor crowding of mixed dentition
What teeth to cross bites most commonly affect?
Incisors and molars
What can a cross bite cause?
Displacement of the jaw and tooth
When is a cross bite most easily corrected?
Mixed dentition
What can having a sucking habit cause?
Proclined upper anterior
Retroclined lower incisors
Buccal segment cross bite
Reduced overbite or anterior open bite
How to stop sucking habits?
Deterrent devices
Plaster on finger
Encouragement
Nail varnish
What 2 ways is bone laid down?
Endochondral - In cartilage
Intramembranous - In membrane
How does bone remodel?
lays down or removes bone from the surface
How to bones connect?
via sutures which are non movable
What is the only bone structure that is movable?
TMJ
What way is the calvarium laid down?
Intramembranous
What do the 6 fontanelles allow for?
Compression of head during birth
When do the fontanelles close?
By 18 months
What does the calvarium grow in response to?
Brain growth
How are the 2 main areas of cartilage within the cranial base laid down by?
Endochondrial
When does the primary dentition start to erupt?
6 months
When is the primary dentition complete?
3 years old
When is root formation complete in the primary dentition?
Complete by 18 months after eruption
When do primary teeth start to exfoliate?
6 years old
When is the permanent dentition finished?
Around 13 years old except 8s
When is root formation complete in permanent teeth?
3 years after eruption
What is leeway space?
Buccal primary teeth are wider than permanent
What is craniosynostosis?
Premature fusing of the sutures on the calvarium causing an abnormal shaped head
What is the most common craniofacial birth defect?
Cleft lip and palate
What side is cleft lip most common on?
Left side
How is CLP diagnosed?
Ultrasound scan at 20 weeks
What happens if there is a delay in diagnosis for CLP?
Difficulty feeding and unsettled infant
Cleft services in Scotland?
MCN
CleftSIS
CLAPA
Changing faces
General problems with CLP?
Breathing
Hearing
Speech
Feeding
Psychological
Dental problems with CLP?
Facial appearance
Hypodontia
Supernumerary
Ectopic
Hypoplastic
High caries rate
