ortho (all stages) Flashcards
Difference between want, demand and need for orthodontic treatment
-Want= individual’s own assessment of their desire for better oral health
-Demand= seeking out the want
-Need= in ‘need’ of intervention by a dental practitioner. Is the treatment justified. Do advantages if offers outweigh possible damage it may cause
Consumer factors influencing demand for orthodontic treatment. And factors influencing provision
Improved appearance
Desire to look ‘normal’ (wide variation perception)
Gender (F want attractiveness more than M)
Age and peer group norms
Parental aspirations
Higher socioeconomic groups
Cost
Awareness and attitude to orthodontics
Perception of treatment need
Access to advice/support/treatment
Proper assessment of treatment need - IOTN to consider who is qualified under NHS
what is the Index of Orthodontic Treatment Need
IOTN measures the impact of a malocclusion on an individual’s dental health and their psychosocial wellbeing. Used also to assess need and eligibility for treatment and allocate care in the NHS.
-there is a dental health component (1-5) and aesthetic components (based on 10 photos)
-usually dental component assessed first. 4 or 5 need treatment. If 3 then do aesthetic component and take this into account
what MOCDO stands for
Missing
Overjet
Crossbite
Displacement of contact points
Overbite
-decreasing in priority
-5i trumps everything (ectopic- not erupted through gum)
how the dental health component is graded 1-5 for IOTN
Grades occlusal traits which could effect the function or longevity of the dentition
Grade 1: no need for treatment
Grade 2: little need
Grade 3: moderate/borderline need
Grade 4: great need
Grade 5: very great need
Worst single feature of a malocclusion noted; not a cumulative index
Need treatment = grade 4 and 5
What are 5a, h, I, m, p, s (very great need) of the IOTN
5a: increased overjet > 9mm
5h: >1 missing tooth per quadrant
5i: ectopic teeth
5m: reverse overjet > 3.5mm with reported masticatory/ speech difficulties
5p: defects of cleft lip and palate
5s: submerged (infraoccluded) deciduous teeth
how the aesthetic component for IOTN is graded (1-10)
Grade 1: aesthetically pleasing
Grade 10: least pleasing
1-2: no need for treatment
3-4: slight need for treatment
5-7: moderate/ borderline need
8-10: definite need
6+ eligible for NHS tx
Tends to be used to grade borderline cases
>6 can get treatment under NHS
For the IOTN index, what do the following mean 5i, 5h, 5a, 4h, 4a, 4d, 3d
5i= very great need, impacted/ectopic teeth
5h=hypodontia >1 per quadrant
5a= >9mm overjet
4h= great need, hypodontia <4missing
4a= >6mm overjet
4d= >4mm contact point displacement
3d=2-4mm displacement
How much overjet requires treatment
> 6mm means great need (4a)
9mm means very great need (5a)
what is a compensating extraction
extraction of the equivalent opposing tooth to prevent over- eruption or maintain buccal relationship.
e.g. first permanent molars with poor long- term prognosis.
What is a balancing extraction
extraction of a tooth on the opposite side of the same arch to maintain the centre line.
examples of removable appliance use
-correcting cross bite. appliance on palate with a screw to gradually widen the arch
-hawley and Essex retainer
-clear aligners
-coverplate
-space maintainer
name some functional appliances used for growth modifications
Removable or fixed orthodontic appliances which use forces generated by the stretching of muscles, fascia and/or periodontium to alter skeletal and dental relationships
-Twin blocks - treats class II division 1 with increased overjet
Medium opening activator - for deep overbite
Herbst (fixed) appliance
-Quad helix- widening arch
-Class III appliances rare as cannot pull mandible back
what tooth is common impacted
maxillary canines
why retainers are used. the 3 types
- worn post ortho to prevent relapse of the final outcome
1. fixed bonded retainer (incisors)
2. Removable Essex retainer
3. Removable Hawley retainer
pros and cons of a Hawley retainer
Easy to modify and adjust, Repairable if broken, More durable than clear plastic, allow settling, good for expansion, can eat with them in.
-good for stopping overbites relapsing
BUT Can interfere with speech, Longer to fabricate (although same day possible), Less aesthetic - visible wire, poor compliance as more bulky, not as well fitting, more expensive
-wear for 6/12 then nights forever
pros and cons with Essex retainer
Cheap, quick and Easily fabricated (Vacuum formed same day), Aesthetic – clear and transparent, Easily cleaned
BUT not durable, If it cracks of breaks it can’t be repaired, May stain over time, May warp if exposed to heat, Top and bottom teeth don’t touch naturally with this type of retainer, Could trap liquids against teeth, must not eat/drink with them in due to erosion, easily lost
what is a Hawley retainer. the components of a Hawley retainer
-labial bow to hold the six anterior teeth in place (this is passive) 0.7mm stainless steel wire (Cr/Ni 18/8) with U loops to allow adjustment.
- an acrylic baseplate palate held to the roof of the mouth by Adams clasps
-Clasp arms are adapted down into the palate
-Adams Clasps 0.7mm stainless steel wire (molars) 0.6 (pre molars) placed each side of the arch for retention
the components of an Adams clasp
-clasp arms: medial and distal to the tooth
-bridge: goes across buccal aspect, width between cusp tips
-arrow heads: curved u shape
the steps in making a Hawley retainer in the lab
-straighten wire and mark position of the first bend
-bend 2 right angles that are the width of the cusps, which will be the bridge
-create the curved arrow heads using the Adams pliers
-more bending to create the clasp arms
-clasp arms adapted down onto palate, leaving 0.5-1mm gap for acrylic to wrap around. tags added to the end to prevent movement within the acrylic
-then do the other arm
-create labial bow to sit over the anterior teeth
-for the acrylic plate, Liquid (monomer) and powder (polymer) are in turn sprinkled on the model ensuring the wires are covered and a thickness of around 2-3 mm across the palate
-The appliance is placed in a pressure pan to allow polymerisation
-trimmed and polished
advantages and disadvantages of removable orthodontic appliances
-can be removed for cleaning, cheaper than fixed, good for tipping movements
-BUT cannot be used for those with poor OH, caries, poor cooperation.
-They can only do tipping movements (cannot do intrusion, exclusion, rotations)
- Lower appliances poorly tolerated
what is a cover plate
Used after surgical exposure in attached gingiva (usually palatal cannine).
-covers exposed wound for 2 weeks, not removed even for brushing.
-maintains dressing (coe-pak) which aids healing/maintains exposure
- Gives comfort post-surgery
-Has Adam clasps for retention
-removable appliance
what is a space maintainer
Maintains space after early tooth loss for a prosthesis or allow a successor to erupt
-otherwise when a tooth moves out, teeth move anteriorly
-adams clasp for retention, metal stops between adjacent teeth, may contain a replacement tooth
-it can be removable or fixed
pros and cons of a fixed retainer
-Advantages: full time, compliance, good for rotations / movement lower incisors. Worn full time so good compliance
-Disadvantages: breakage, repair difficult, overbite in upper, OH difficult – plaque retentive. must be used with Essix retainer. can cause movements and recession if not passive
what malocclusion does twin blocks correct. how they work. unwanted tooth movement. Ideal age
treats class II division 1 with increased overjet
-Pulls mandible back, resulting in Mandible musculature pulling it forwards. This moves the maxillary teeth back and mandibular teeth forward.
-encourages mandibular growth and reduces maxillary growth
=About 75% of the effect is dental (tooth movement) and 25% change in skeletal growth
-Causes lower to procline, but we want to avoid this
-best in girls 11-13 + boys 12-14 during adolescent growth
pros and cons of fixed appliances
-capable of greater range of tooth movement than removable, good for complex cases, compliance less of an issue, does not affect speech as not on palate
-BUT: need good OH, have to avoid sticky hard foods, tricky to clean, can cause root resorption
what materials are used for the archwire for braces
Wires initially flexible (nickel titanium) and then use more rigid wires for tooth movement (stainless steel)
What is involved in a full orthodontic assessment
- History: reason for attendance (complaint, is it realistic). Medical and dental history (motivation, phobias, trauma, OH)
- Extra oral exam: skeletal pattern (class I, II, III) Asymmetry. FMPA, LFH. Lips, NLA.
- Intra oral exam: teeth present, OH, periodontal state, disease, teeth with poor prognosis
- Occlusion: Upper and lower labial & buccal segments- crowding, spacing, displacement, rotation. Incisal relationship, overjet, overbite, centre lines, molar/ canine relationships, crossbites
- Radiographs & cephalometry findings
- IOTN
- Problem list, arrange referral if necessary
For extra oral ortho exam, explain antero-posterior relationship, vertical relationship, transverse, lips and NLA
-A-P relationship: A & B points (deepest concavity of maxilla and mandible). Class I (mandible 2-3mm post to maxilla) Class II, Class III (mandible protruded)
-Frankfort Mandibular planes angle: intersection of maxilla (alar-tragal) and mandible plane
-Lower face height: mid=lower. Glabella to columella to menton
-Transverse: Asymmetry, deviation, skeletal discrepancies
-Lips: competence. Gingival display smiling. 2/3 of upper incisors should show
-Nasolabial angle: 90-110 degrees
Average values for: How much teeth should be on display when smiling, NLA, overbite %, class 1 ANB, LFH %
-75-100%
-90-110 degrees
-20-40% lower incisors covered
-2-4 degrees
-55%
How to measure FMPA
-Frankfort plane v mandibular plane along base of mandible
-on a ceph: Frankfort plane is upper margin of external auditory canal (porion) & lowest part of orbit
-extra orally you cannot see these points so we tend to use the alar tragal line
-If FMPA is normal, the 2 intersecting lines should meet at the back of the head.
If meet in front of the back of the head, the FMPA is increased, if they meet behind the back of the head, the FMPA is reduced.
How to measure overbite and overjet. When is complete overbite going to occur in
-Overjet: measure greatest distance between upper and lower incisors (centrals/laterals)
-Overbite: when in ICP, measure vertical distance between incisor tips. Can be hard so usually done as a % of lower incisors covered by uppers. 100% common in class II div 2. 0% for class III
-Complete = contact with tooth or tissues
Incomplete= no contact between tooth or tissues
Explain class I, class II div 1, class II div 2 and class III incisor relationships
-class I: lower incisor edges occlude with or lie immediately below the cingulum plateau of the upper central incisors
-class II: lower incisor edges lie posterior to the cingulum plateau of upper
- Div 1 – upper incisors are proclined, OJ increased
- Div 2 - upper incisors are retroclined, OJ minimal / increased
-class III: lower incisor edges lie anterior to the cingulum plateau of the upper central incisors. OJ is reduced or reversed
Explain the class I canine and molar relationship
-Class I canine= upper 3 occluded between lower 3 and 4
-Class I molar= MB cusp of upper 6 occludes with MB groove of lower. Cusp to cusp would be 1/2 unit class II
What is a cross bite and scissor bite.
-usually upper arch is slightly wider than lower, meaning palatal cusps of upper posteriors are the functioning cusps, and lower buccal are functioning
-buccal crossbite= upper is narrower than lower. Buccal cusps of the upper molars sit in the occlusal fossa of the lowers. Commonly seen in Class III
-lingual cross bite (aka scissor bite)= upper arch a lot wider, so lowers site completely inside upper
What are the 3 levels of crowding. How to create space for each
-Mild = 2-4mm. No extraction needed. Interdental stripping
-Moderate = 4-8mm. XLA
-Severe = > 8mm. XLA in each quadrant +/ anchorage reinforcement
Benefits of orthodontic treatment
-function: mastication and speech.
-dental health: TMJ, tooth impaction, easier to clean, caries, perio disease, trauma (reduces risk of cyst formation, root resorption of adjacent teeth, soft tissue trauma)
-aesthetics: confidence, self esteem
-conservation of space
Risks of Ortho treatment (what are the 3 main ones)
1-root resorption: inevitable 1-2mm length loss. Increased risk if roots thin, excess force, asthma, PDL damaged
2-loss of vitality (pain and discomfort): most experience transient reversible pulpits in first 4 days. Only experience irreversible if history of trauma [can do treatment on RCT if has no PAP]
3-relapse: if retainers not worn, due to elastic recoil of PDL fibres. (Remodel over ~1year)
-initial pain for 3-5 days after appliance adjustment
-bone loss: usually no long term effect. Due to poor OH, excess movement, pre-existing disease
-time off school due to poor aesthetics/bullying
- gingival recession, gingivitis
-allergy to nickel
-ankylosis
-root or crown damage of adjacent teeth
-soft tissue trauma: from head gear (eye injuries allergy) burns, gingiva and mucosa (applying wax to brackets helps)
-caries: appliances tricky to clean
-TMD (little evidence)
-change in profile and soft tissue contour (thick/thin lips, angles etc.)
-discontinuation of treatment
-dissatisfied patient
When should retainers be worn after treatment (Essix and Hawley)
-essix retainers worn at night time for at least a year, then occasionally for a lifetime
-Hawley retainers worn full time for 6 months, then at nights/ occasionally for a lifetime
Why crowding of lower incisors is likely after treatment/ as you age
-mandible growth carries on later than maxilla, so lower incisor crowding likely. End of growth is mid 20s so it is important to have retainers
-natural ageing process
- weak theory that mesial migration of posterior teeth due to transeptal fibres and erupting 8s
Aetiology of orthodontic problems
-small jaws
-maxilla/ mandible discrepancy (class I, II, III)
-habits- digit sucking
-soft tissues- lip trap, active lower lip, large tongue
-dental- crowding, spacing, early loss of deciduous, hypodontia, supernumerary, trauma, extractions, tooth size discrepancy, incisor inclination
If someone is class I, what is the likely cause of their orthodontic problems. What is required to treat
Due to dental problems (rather than skeletal or soft tissue)
-crowding, spacing, early loss of deciduous, hypodontia, supernumerary, trauma, extractions, tooth size discrepancy
-fixed appliances, removal appliances, may be multidisciplinary
When would surgery for orthodontics be considered
-for severe cases that a functional appliance would not work
-once growth has ceased, at 18+ years
-use functional appliances if still growing
Aetiology of class II orthodontic problems and how to treat
-smaller mandible, thumb sucking (div 1), lower lip trap (div 1), active lower lip (div 2)
-functional appliances
-orthognathic surgery
-orthodontic camouflage with fixed appliances, XLAs, anchorage
-break habits
Extractions required before fixed appliances for class II
-Space is required to relieve crowding and reduce the overjet
-commonly upper 4s. Only lower 5s if crowding
Aetiology of class III orthodontic problems
-bigger mandible
-smaller maxilla (so crowding more common in upper)
-larger tongue
-use functional appliances (although less effective than in other classes) and surgery to change skeletal discrepancy
-camouflage
-break habits
-use fixed and removable appliances to tidy up malocclusions
Treatment options for mild, moderate and severe class III
-Accept if pt is happy with their teeth
- Mild –crossbite corrected with removable / fixed appliances (camouflage by proclining upper incisors and retroclining lowers)
-Moderate – either camouflage treatment to
hide the skeletal discrepancy or functional
appliance treatment (rare) to try and modify growth
-Severe – orthognathic surgery
What is orthodontic anchorage reinforcement
-resistance to unwanted tooth movement
-newtons third law= For every action (a force) there is an equal (same magnitude) and opposite reaction. Therefore, if an object exerts a force on another, the second exerts an equal an oppositely directed force on the first one
-want anchorage if a tooth has to move lots to close a gap. Eg. XLA 5. 6 will move more than the anterior teeth as root surface area is less than anterior teeth. Anchorage used to keep the 6 in the position it is in
-eg. Nance arch- appliance on palate
eg. temporary anchorage device (mini screws into bone)
eg.-headgear
eg. transpalatal arch
Role of a GDP in orthodontics
GDPs never expected to plan orthodontic extractions
GDPs need to understand why an orthodontist wants you to extract certain teeth
Can question why an orthodontist wants something done a suggest an alternative
You will be seeing patients with these applainces so need to encourage good OH
Looking out for problems. And contacting patients’ orthodontist
How to help make the decision of extracting a 4 vs 5 vs 6
-position of overcrowding: -which will give appropriate space to relieve crowding, reduce overjet, reduce overbite, reduce curve of spee
-prognosis (eg. hyperplastic, carious)
-amount of space required
-incisor/molar relationship
-anchorage requirements (so would avoid 6 ideally)
-appliances to be used
-patient profile
4s -most common. for moderate to severe anterior crowding, reduce OJ
5s - common. for mild to moderate crowding (as narrower). or if severely displaced which is common in early loss of deciduous
6s- not too common. If poor prognosis, limited space anteriorly. Requires anchorage reinforcement. Consider compensating to prevent over eruption
How to create space
-primary premolars and canines are larger than adults teeth so this creates space =leeway space (~2mm)
-distal movement using headgear
-arch expansion
-incisor proclination
-interproximal stripping (using files or polishing strips between teeth)
-extractions
Reasons for extracting 7s and 8s during ortho
7s- to allow distal movement of 6 using head gear, poor prognosis, to facilitate eruption of 8
8s-Previously thought to cause lower incisor crowding, but there is no proven link. May be required for orthognathic surgery. Follow NICE guielines for wisdom tooth removal (multiple pericoronitis episodes, unrestorable caries etc.)
Which primary teeth are fine to extract. But which to avoid
-incisors= generally OK. Don’t need to balance
-C and D= probably avoid as causes centreline shift. Need to consider balancing. Cs have highest risk of shift
-E= AVOID as important for space maintenace, otherwise 6s drift mesially when erupting. Never balance these
what responses do the following ortho forces over the timeframes cause (<1s, 1-2s, 3-5s, long duration)
Less than 1 second – Pizoelectric effect (normal function)
1-2 Seconds: PDL fluid expressed, tooth moves in socket
3-5 Seconds: PDL fluid redistributed, Tissues compressed = pain
Longer duration: Tooth moves In socket, bony changes occur
what occurs to bone/PDL/teeth when heavy ortho forces are applied
3-5 seconds: Blood vessels occlude on one side
1 min: Blood flow cut off to the PDL on that side
Hours: Cell death in the compressed area
3.5 days: Cell differentiation, undermining resorption begins BY osteoclasts PAIN
7-14 days: Lamina Dura is resorbed – tooth movement
Tension= stretching of PDL and stimulation of osteoblasts leading to bone depositiom
Compression= compressed vessels, osteoclasts cause resorption
Stability of Class III correction may be compromised by what
-inadequate overbite
-further growth
Who is eligible for NHS ortho tx
<18 years old with Grade 4 or 5 dental IOTN component or 6+ aesthetic component
Explain 1)SNA, 2)SNB, 3)ANB, 4)UIncMxPl, 5)LIncMnPl, 6)MMPA, 7)LFH. And what it means if they are increased or decreased
1 & 2) maxilla/ mandible relative to anterior cranial base. Prognathic maxilla/ mandible increased, retrognathic if decreased
3) relative position of maxilla to mandible. >4 degrees class III, <2 class II
4 & 5) upper/ lower incisors to maxillary/ mandible plane. Proclined or retroclined incisors
6) angle between maxillary and mandibular planes. Increased=reduced overbite or anterior open bite. Reduced= increased overbite
7) LFH -columnella to menton. Increased=reduced overbite or anterior open bite. Reduced= increased overbite
What to write in ortho referral letter.
-Why you are writing. Reason for referral.
-Pt details. Previous treatment, MH, DH, motivation, OH
- Features of malocclusion: incisal and skeletal relationship, pt concerns, Problems list (MOCDO), IOTN
-Summary of radiographic and ceph findings
Is crossbite common in class II or III
III
As narrow maxillas or wider mandible
Does class II or III tend to get worse with age
class III as mandible continues to grow
Class II can get better
% population that have hypodontia of upper 2s. Primary hypotonia %. Permanent hypodontia
-2%
-0.3%
-2-8%
Why it is important to ask about recent trauma for ortho patients
-root resorption, ankylosis, loss of vitality will affect ortho treatment
What are anterior and posterior bite planes
-anterior= for deep overbites. opens the bite to allow posterior to erupt (Dahl concept) while preventing the anteriors to erupt anymore. Vertical development of the alveolus and condyles with also grow
-posterior= for anterior open bites. allows anteriors to erupt, helps to increase the overbite
-only used in an actively growing patient
forces require for the 5 different types of orthodontic movements
-intrusion= 15-25g
-extrusion= 50g
-tipping= 50-75g
-rotational - 50-100g
-translational 100-150g
causes of upper midline diastema in a 12 year old. How to manage
-microdontia, large maxilla, small teeth, proclined upper anteriors, midline supernumerary, prominent frenum, hypodontia
-physiological and may close when canines erupt
-assess the cause
-ortho and/ or restorative
-asssess of the canine will close the diastema
When to refer a patient to ortho
-usually once all permanent teeth erupted (12ish) for fixed appliance
-If considering functional appliance (i.e. skeletal pattern discrepancy), need to harness pubertal growth spurt (10-12 females, 11-13 males)
-Consider Early referral (mixed dentition) for interceptive treatment, eg. Crossbites, Unerupted teeth (1 year after contralateral/expected) Poor prognosis 6s (around age of 9) Ectopic canines (if can’t palpate at 9)
-Once growth ceased (at least 18) for orthographic surgery
