orthodontics Flashcards
(123 cards)
1
Q
A Patient has an anterior crossbite and requires fixed appliance treatment;
Name 4 fluoride supplements you would give the patient to prevent
decalcification, naming the dose and frequency?
A
2x daily Duraphat toothpaste 2800ppm or 5000ppm
1x daily Mouthwash 225ppm 0.05%
1x daily Fluoride tablet 1mg
4x yearly (HR patients) Duraphat fluoride varnish 22,600ppm
2
Q
Name other methods to prevent decalcification other than fluoride supplements? (3)
A
To prevent decalcification:
Oral hygiene instruction (before and during)
- Minimum 2x per day very thoroughly
- After every meal
- Use disclosing tablets
- Target gingival margins
- Target around each bracket
Diet advice
- Encourage non-cariogenic diet
- Educate impacts of sugar amounts and frequency
- advise using free gum to stimulate saliva (buffering)
Case selection of pxs for ortho
- good OH prior to tx
- motivated
- low caries risk
High risks patients have - pre-existing decal, erosion, caries history (Lots of restorative tx)
3
Q
List 8 potential risks of orthodontic treatment other than decalcification?
A
- (Decalcification )
- Root resorption
- Relapse
- Soft tissue trauma
- Loss of vitality
- Poor/failed tx
(above are the most important)
_
* Recession
* Loss of perio support
* Headgear injuries
* Enamel fracture/toothwear
* Allergy
4
Q
Patient is 30 years old and he is worried with his class 3 incisors relationship, How would you assess patients skeletal anterior-posterior relationship? (3)
A
with the frankfort plane horizontal to the floor;
- Visual examination
- palpate the skeletal bases
lateral cephalometry
5
Q
List the the classes of AP relationship?
A
Class I: Maxilla 2-3mm in front of the mandible
Class II: Maxilla is > 3mm in front of the mandible
Class III: Mandible is in front of the maxilla (less than 2-3mm)
Teeth reduced/reversed overjet
6
Q
Describe a class 3 anterior posterior skeletal relationship.
A
Class III: Mandible is in front of the maxilla
(maxilla is less than 2-3mm in front of the mandible)
Teeth reversed overjet
7
Q
Name 4 special investigations an orthodontist would carry out before starting tx. (6)
A
(not special invetsiagtions)
Extra & Intra-oral examination
BPE
Radiographs: OPT, Lateral cephalometry
impressions for study models
clinical photographs
sensibility testing
8
Q
Name 4 intra-oral features of a class 3 malocclusion.
A
- Class III incisors
- Often but not always C3 molars
- reversed/reduced overjet
- Reduced overbites or AOB present
- Crossbites (Anterior or posterior)
- Crowded maxilla
- Aligned or spaced mandible
- Dentoalveolar compensation commonly seen = proclined upper incisors and retroclined lower incisors
- Tendency for displacement (on closing) to achieve posterior contact
9
Q
Name the systemic condition that causes the mandible to continue to grow.
A
Acromegaly - excess of growth hormone produced by the pituitary gland
e.g. via a pituitary adenoma (benign)
other symptoms:
enlarged hands and feet
enlarged facial tissue features e.g. nose, lips
10
Q
How is a class 3 malocclusion managed? (5)
A
- Accept and monitor
Mild cases
- Used when Px has n concerns
- Used when px has no Dental health indications (displacement or attrition) - Early URA treatment to correct incisor relationship (e.g. crossbite)
- Growth modification- Reducing/redirecting mandibular growth and encourage maxillary growth via functional appliances e.g. Reverse twin block, Frankel III, protractiion headgear and rapid maxillary expansion.
- ortho camoflauge - maintain the underlying skeletal base relationship and create a class I incisor relationship (proclining UI +retrocline LI+ Correct overjet)
- Ortho + orthognathic surgery:
* Pt with aesthetic or functional concerns AFTER Growth is complete
* Moderate/Severe skeletal discrepancy
11
Q
Patient attends with an anterior crossbite involving 21
- When is the best time to begin treatment?**
A
As soon as you detect it
12
Q
What 3 features of the anterior crossbite involving 21 malocclusion would make it amenable to treatment with a URA? (4)
A
only single tooth movement
palatal tipping (can move to a positive overjet)
must have good overbite - aids stability
must have adequate space to move teeth forward
13
Q
Design a URA for fixing an anterior crossbite involving 21.
A
Please construct a URA to correct the anterior crossbite on tooth 21:
A- 21 = Palatal Z spring (0.5mm HSSW)
R- Adam’s clasps (0.7mm HSSW) on the 14, 16, 24, 26
A- yes (1 tooth only)
B- Self cure PMMA with posterior bite plate.
14
Q
What is hypodontia?
A
Congenital absence of one or more teeth (excluding the 8’s)
15
Q
name syndromes associated with hypodontia. (4)
A
- Ectodermal Dysplasia
- Down Syndrome
- Cleft Palate
- Hurler’s syndrome
- Incontinentia pigmentii
16
Q
how is hypodontia diagnosed? (2+5)
A
An examination and an x-ray are needed.
Observe:
* Early on in life
* Delayed or asymmetric eruption
* Retained or infra-occluded deciduous teeth
* Absent deciduous tooth = guaranteed absence of permanent
* Tooth form = tapered and small teeth commonly associated with hypodontia
17
Q
how may hypodontia present to a GDP? (6)
A
- Delayed or asymmetric eruption
- Retained or infra-occluded deciduous teeth
- Absent deciduous tooth = guaranteed absence of permanent
- Tooth malformation = tapered and small teeth commonly associated with hypodontia
- ectopic canines
- Cleft lip and palate.
18
Q
What are the possible tx options for hypodontia? (6)
A
- Accept
- Restorative tx alone
- Orthodontics tx alone
Combined orthodontic & restorative treatment:
- open space + restorative e.g. RPD, RBB, conventional Bridges, implant, autotransplantation.
- close space + no restorative (simple)
- close space + restorative (space closure plus)
19
Q
Name 4 members of an MDT involved with hypodontia.
A
GDP - Recognition
orthodontist
prosthodontist
restorative
oral surgeon
Specifically the hypodontia clinic
20
Q
Early tooth loss: What 4 factors worsen the effects of early loss of primary teeth? **
A
Age of the child
Which arch (loss in maxilla= worsen)
loss in an already crowded arch
which tooth is lost - E (worst).
21
Q
when might you consider balancing a primary tooth
extraction? **
A
When there is planned loss of a primary C
- if you dont balance = midline shift
(optional)
When there is planned loss of a primary D
- more likely to balance on the other side if done under GA
(not routine)
When there is planned loss of a primary E = not routinely done however causes significant mesial drift of the permanent 6 = cause crowding
22
Q
give 4 reasons for an unerupted central.
A
Early loss of primary teeth
prolonged retention of primary teeth
pathology
- Presence of a supernumerary
- Odontome
- Cystic formation
trauma = dilaceration of the root/crown
crowding upper labial segment
23
Q
what are the treatment options for an unerupted central?(6)
A
- Do nothing
- If no supernumerary/pathology = Maintain space/create space and monitor for 1.5 years
- XLA supernumerary/ retained primary tooth and allow spontaneous eruption
- XLA supernumerary/ retained primary tooth and create space (URA or fixed)
- XLA supernumerary/ retained primary tooth and surgical exposure
- Closed exposure with gold chain if close to the surface and in the line of the arch
- open exposure
if > 9y/o use traction and fixed appliances
(bonded retainer after treatment)
- If significantly dilacerated or ankylosed = remove the incisor and maintain space
24
Q
Class II div 1
- What is the BSI classification of class II div 1?
A
Where the lower incisal 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 inclincation
25
What are the dental features in class II div 1 patients? (5)
* Increased overjets
* Overbite varies (If deep- can have palatal trauma)
* Variable tooth position( good alignment, crowding or spacing)
* class ii Molar relationship
*Drying of gingivae & worsening of pre-existing gingivitis (Due to habitually parted lips)
26
What soft tissue problems are associated with class II div 1 malocclusion? (3)
Lower lip trap (getting behind incisors causing increased proclination of uppers)
Incompetent lips due to incisor prominence (increased trauma risk)
habitually parted lips = worsens pre-existing gingivitis
poor anterior oral seal
tongue thrust- to help achieve the anterior oral seal.
27
What are the 5 features of a twin block appliance?
2x bite blocks
Adams clasps
baseplate
labial bow
midpalatal screw
28
What makes a class II div 1 malocclusion amendable to correction via removable appliance therapy? (3)
If :
- very mild
- overjet is caused by proclined and spaced incisors
- If there is space to retrocline the UI by tipping & tilting movements.
-If there is an overbite = aids stability
29
What are the tx options for class II div1?
1. Accept
- In a mildly increased overjet
- In a significant overjet but patient not concerned
2. Growth modification with functional appliances e.g. Twin block, Frankel 2, bionator, Herbst – act on underlying skeletal bases
3. URA and Simple tipping of teeth
4. Camouflage – fixed appliances correct incisor relationship without influencing the growth of the jaws. (may need extractions to allow retraction of teeth)
5. Orthognathic surgery
When there is a severe anteroposterior skeletal discrepancy or vertical discrepancy
30
What is dentoalveolar compensation? **
The body’s attempt at creating a ‘normal’ occlusal relationship between the upper and lower arches when not it doesn't occurring naturally.
Orthodontically-
E.g. proclination of UI by the tongue. Retroclination of LI by the lip.
Toothwear (compensation for loss of tooth surface)
E.g. the bone gets longer to prevent the incisal edge moving -leaving no room for restorations
31
what is the BSI classification of class III malocclusion.
Lower incisor edge occludes anterior to the cingulum plateau of the upper central incisor
The overjet is reduced or reversed
not all class 3's have a reversed overjet - can be edge to edge
32
What 4 special investigations are carried out for class 3 patients?
Height and weight charts - to assess if patientis still growing
Radiographs: OPT, Lateral cephalometry
impressions for study models
clinical photographs
sensibility tests
33
List treatment options for class 3 malocclusion.
1. Accept and monitor
-mild cases
- No patient concerns
- No Dental health indications (displacement or attrition)
2. Interceptive treatment (mixed dentition) e.g. a URA (functional appliance) to correct crossbite.
3. Growth Modification- to redirect/reduce mandibular growth and encourage maxillary growth using:
Reverse Twin block/ protractor headgear/ bollard implants.
4. Orthodontic camouflage
Accept underlying skeletal base & using fixed appliances to achieve class 1 incisors by:
Proclining upper Incisors
Retroclining lower incisors
Correcting overjet.
5. Ortho + orthognathic surgery:
* Pt with aesthetic or functional concerns
* Growth completed
* Moderate/Severe skeletal discrepancy
34
Define a supernumerary.
An additional tooth or tooth like entity
35
Supernumerary teeth can be classified according to their position and / or shape. Please list and describe four different morphological types of supernumerary teeth you know of:
| 2020 Paper2
* Conical = cone shaped (most common)
* Tuberculate = barrel shaped, has tubercles
* Supplemental = looks like tooth of normal series however can be smaller (commonly a lateral incisor)
Both erupt - Keep whatever one is more suitable for orthodontic tx
* Odontome = irregular mass of dental hard tissue
Can either be compound or complex
36
what are the effects of supernumeraries on the permanent dentition? (6)
| 2020 Paper 2
Delayed/failed eruption.
Displaces eruption of adjacent teeth causing an ectopic position.
Crowding.
Impaction
cyst formation (dentigerous cysts are associated with unerupted teeth)
root resorption of adjacent teeth
37
Child with mandibular displacement on closing on RHS with posterior unilateral cross bite of d, e and 6 on RHS
- What is mandibular displacement on closing?
| 2022 Paper 2 q25
Where the mandible to deviates to one side to achieve intercuspation.
This is because the interarch width discrepancy causes the upper and lower posterior teeth to meet cusp to cusp - mandible deviates to one side to prevent this and achieve ICP
38
Why would you correct a mandibular displacement? (4)
| 2022 paper 2 q25
Can lead to;
TMD
asymmetric growth
Tooth wear (attrition)
Gingival recession
39
What would you use to correct a unilateral posterior crossbite?
Provide design details.
| 2022 paper 2 q25
Please construct an URA to correct the Unilateral posterior crossbite.
**A**- midline palatal screw (baseplate cut as shwon in image)
**R**- Adam's clasps (0.7mm HSSW) on 4s and 6s
**A**- baseplate provides
**B**- Self cure PMMA baseplate with flat posterior bite plane
40
Design the URA for a child with mandibular displacement on closing on RHS with posterior unilateral crossbite of d, e and 6 on RHS.
Please construct. an URA to correct the unilateral posterior crossbite.
A- Midline palatal screw (baseplate cut as shown in image)
R- Adams clasps on the Ds (0.6mm HSSW) and Adams clasps on the 6s (0.7mm HSSW)
A-
B- Self cure PMMA baseplate with flat posterior bite plane.
41
Give three uses of a URA other than tipping and tilting teeth (6)
Can be adapted to reducing an overbite
Retainer
habit breaker
space maintainer
expand upper arch
42
Write a prescription for a URA to reduce a 6mm OJ, 1st premolar have been extracted and previous URA retracted canines and reduced the overbite. Patient
has permanent dentition.
Aim: Please construct an upper removable appliance to reduce the overjet from the 12-22 and correct the overbite.
A: 11, 12,21, 22 – Roberts Retractor 0.5mm HSSW + 0.5mm ID tubing
13 + 23 – Mesial stops 0.7mm flattened HSSW
R: 16 + 26 = posterior retention Adams clasp 0.7mm HSSW
Roberts retractor also acts as retention
A: Yes and no – moving more than 2 teeth however the teeth we are moving have short roots.
B: Self cure PMMA + Flat anterior bite plane FABP (OJ + 3mm)
43
List 6 signs of good wearer/compliant patient with a URA on visit.
Patient arrives wearing the URA
Patient can insert and remove the URA easily
Can speak without impinging speech with URA
Device looks worn – wear on acrylic
Active component now passive as it needs to be re-activated again due to movement
Teeth have moved – 1mm per month
44
what are the difficulties experienced with URAs? (4)
1) The appliance will feel big and bulky – takes time for patient to get used to.
2) There will be mild discomfort and pressure on the teeth – indicates that this is working correctly (don’t use sore and pain)
3) Patient will initially have a lisp (Practice reading aloud to let tongue adapt to the appliance)
4) Initial production of lots of saliva – this will disappear over 24 hours.
45
What instructions would you give to the patient with a URA? (6)
1) Wear the appliance 24/7 including eating and sleeping
2) Take it out and clean it with a soft brush and soap under the luke warm tap after every meal
3) Put it in a protective container when carrying out contact (rugby) /active (sharp intake of breath) sports
4) Avoid hard and sticky food and exercise caution with hot food/drinks – heat is insulated as it acts as palatal coverage
5) Emphasise that non-compliance prolongs treatment
6) Provide emergency contact details – use if you have problems with the appliance
46
Outline the delivery of a URA steps. (4 & 6)
Check prior to fitting:
1) Make sure you have the correct appliance for the correct patient
2) Check that it matches the design
3) Run finger across it to ensure there are no sharp edges (safe for patient)
4) Make sure there are no signs of damage to the wirework (ensure integrity of the wirework)
Once in the patients mouth:
1) Ensure the fit doesn’t cause trauma – no blanching
2) Check the posterior retention – is it adequately going into the undercuts: check the flyover first and then the arrowhead in the undercut.
3) Check the anterior retention
4) Activate the appliance – The URA arrives passive- so we need to activate the active components. Activate a couple initially and active others later.Want to achieve 1mm movement open month. You can get the patient used to the appliance then come back and activate it later (not recommended as it prolongs the time)
5) Show them the correct way to put in and take out the appliance and get them to demonstrate this back to you.
6) See patients every 4 to 6 weeks
47
What 5 factors can cause displacement forces of a URA?
Tongue
Gravity
Mastication - patients should eat with the appliances in
Talking - creates vibrations through the palate
Active component - difficult to control
48
Patient has a 12mm overjet, well aligned arch and ectopic canines
- What are the possible complications of these features? (5)
OJ:
- trauma
- incompetent lips
- habitually parted lips = worsen pre-existing gingivitis
- difficulty speaking/eating
- psychological aspects - being teased
Ectopic canine:
- external resorption of adjacent teeth crown/roots
- cyst formation
- resorption of the canine crown
- ankylosis of the unerupted canine
49
What are the dental advantages and disadvantages of
fixed, holly and pressure vacuum formed retainers?
Fixed:
Advantages:
- Maintain corrections of diastemas/rotation
- Aesthetics
- Doesn’t interfere with the occlusal surfaces
- Compliance (attached 24/7)
- Cheaper (not for patient)
- Small and unobtrusive
Disadvantages;
- plaque trap
- Fracture and if composite debonds debris and sugars can leach beneath (must be checked at each check-ups)
- High failure rate (overbites and leading with upper ants when biting)
- Doesn’t incorporate all the teeth (no posterior retention)
Holly:
Disadvantages:
- Aesthetics poor
- Compliance poor because removable
- Bulky = affect speech and increased saliva
- Impinge on tongue space
- Problematic with lingual frenal attachment
- Expensive to produce
- Time consuming to produce
Advantages:
- Removable (for cleaning)
- Strongest and most resilient
- Incorporates all the teeth
- No tooth prep required
- No occlusal coverage = occlusal settling
- Can be adjusted to become active (passive to active and then can be made passive again)
Baseplate can provide anchorage when they become active
Thermoplastic:
Advantages:
- Aesthetics (if made correctly)
- Improved compliance
- Removable for cleaning
- Lower cost
- Incorporate all the teeth
- Can be altered (to stop at 6’a) if 7’s PE then get a new one when the 7’s erupted
- Better tolerated
- No tooth preparation
- Can correct minor tooth movements (become temporary positioner)
Disadvantages:
- Can break over time
- Stain and discoloured (when cleaned with toothbrush and toothpaste)
- If you don’t wear it, it doesn’t work/you can’t put them back in
- Doesn’t allow occlusal settling (props the bite open)
- Can cause caries if you wear after sugary foods/drinks
- Can deform when cleaning with boiling water
- Lost
- Use inappropriately for tooth whitening
50
25 year old complains of upper teeth being slightly crooked and wants them
straightened after having declined treatment as a teenager.
He has florid marginal gingivitis and no caries.
He has a skeletal class I pattern with a class II div 1 incisor relationship with proclined upper incisors and mild anterior crowding.
- What information, relevant to his provision of orthodontic care, do you need to provide for the orthodontist?
Name, age, sex of patient
HPC, relevant medical & dental history (Including habits)
(already got - Incisor relationship and Skeletal base)
E/O- TMJ/ Lips( competent/ lip trap)
IO- Teeth present/absent, OH status, BPE, perio status and teeth with poor prognosis
Lower arch incisor inclination and crowding
Upper arch incisor inclination and crowding
OverJet, Overbite, centrelines, molar relationships, canine relationship crossbites/ mandibular displacement.
IOTN (index of orthodontic need) score: this is how much the patient requires treatment from the point of dental health and improving their psychosocial wellbeing.
Attach radiographs (OPT) and clinical photographs
51
25 year old complains of upper teeth being slightly crooked and wants them
straightened after having declined treatment as a teenager.
He has florid marginal gingivitis and no caries.
He has a skeletal class I pattern with a class II div 1 incisor relationship with proclined upper incisors and mild anterior crowding.
**
During treatment, patient has a debonded bracket and demineralisation around remaining brackets, how would you manage these problems?**
Ask the patient what happened & check where the debonded bracket is?
Refer to A&E if you suspect possible aspiration risk.
Debonded bracket:
1. check for caries.
2. check wire integrity and no distortion
3. Can the bracket be rotated?
**Yes**-remove the ligature and bracket
(cant rebond since you don’t know the prescription of the individual brackets)
**No**- Put a ligature on the bracket to secure it and make the patient aware – don’t try to twist it off as you could cause more damage. Advise them to move it aside and clean during brushing.
Demineralisation:
Give Patient the bracket, provide thorough OHI, prescribe 2800/5000ppm fluoride toothpaste, diet advice and emphasis the importance of compliance or braces may have to be removed completed to prevent decay.
Tell them to see orthodontist at earliest to rebond to prevent disruption of the teeth.
52
25 year old complains of upper teeth being slightly crooked and wants them
straightened after having declined treatment as a teenager.
He has florid marginal gingivitis and no caries.
He has a skeletal class I pattern with a class II div 1 incisor relationship with proclined upper incisors and mild anterior crowding.
**The ortho treatment is removed due to poor compliance, he asks about extraction of upper incisors and upper partial denture, what would be the
potential long term risks I) loss of upper incisor teeth (4 points) and II) provision of an upper removable partial denture (5 points).**
Loss of incisors:
- poor aesthetics
- functional problems (eating and speech)
- Drifting of adjacent teeth and spacing of the remaining dentition
- psychological impact
-resorption of the ridge & loss of proprioception due to loss of the PDL
RPD:
- Food/plaque trap
- increase caries/perio risk of remaining teeth
- Patient may not like the denture (it will take a while to get used to.
-importance of denture hygiene (Removing the denture at night/cleaning it)
- teeth may need to be prepared/modified to retain the denture
53
25 year old complains of upper teeth being slightly crooked and wants them
straightened after having declined treatment as a teenager.
He has florid marginal gingivitis and no caries.
He has a skeletal class I pattern with a class II div 1 incisor relationship with proclined upper incisors and mild anterior crowding.
The ortho treatment is removed due to poor compliance, he asks about extraction of upper incisors and upper partial denture,
He doesn’t want to wear a denture and asks about crowns, why would you advise against this option? (4)
destructive to tooth tissue
irreversible
all restorative will fail - lifespan of 10 years
OH not good enough to ensure longevity of the restoration.
54
25 year old, had ortho removed due to poor compliance and pottential treatment option of extraction & RPD.
What advice would you give X to maintain his oral health in the long term?
* Brush 2x daily morning and night - For 2 minutes with a 1450ppm fluoride toothpaste
* Brushing at night allows fluoride retention overnight
* Spit the toothpaste out - do not swallow
* Do not rinse mouth after brushing
* Avoid eating or drinking after brushing teeth before bed
* Avoid eating and drinking for 30 minutes after brushing in the morning - it will wash away the fluoride.
* don't use mouthwash directly after brushing (separate time of day)
* brush using the modified bass technique;
Work in a systematic way
Hold brush at the gum line The bristles should contact both the gum and the tooth
Forwards and backwards motions and swipe the bristles towards the biting surface in a rolling motion.
* brush between teeth using interdental brushes/floss
I would also provide advice about keeping the RPD clean:
* Remove the RPD at night.
*Clean the RPD by soaking in a denture cleaning solution for 15 minutes once a day.
*Clean and rinse the RPD after eating
55
What are the oral signs of thumb sucking?
- Proclined upper incisors
- Retroclined lower incisors
- Asymmetric AOB or reduced OB
- Unilateral posterior crossbite
- naroow upper arch.
56
Explain the effects of prolonged digit sucking habit has on posterior dentition?
The thumb sucking causes the tongue to be held lower and the cheeks moving in and out from the sucking narrows upper buccal segments/ the space between the posterior teeth.
The upper jaw is now the same width as the lower jaw (inter arch width discrepancies) and the patient unconsciously decides to bite down on one side/deviate to achieve maximum intercuspation = posterior unilateral CB
57
What 4 methods can be used for stopping NNSH? (Non nurturing sucking habit)
URA habit breaker – i.e. goal post (patient has to be motivated)
Fixed habit breakers – cemented - rake
Foul tasting ointment painted on digit
BMT - positive reinforcement
58
What is the incidence of CLP in UK?
100 cleft births per year
- 1:700 live births
59
What are the general health implications of CLP? (6)
* Aesthetics
* Speech: palate involvement = hypernasal voice - air goes through the nose when speaking
* Dental - affecting teeth growth and location
* Hearing: more likely to suffer with glue ear
* Others e.g. cardiac abnormalities
* Function- Suckling problems (nurses show parents how to combat this with a soft bottle)
60
What are the dental features of CLP? (5)
1. Impacted teeth
2. Missing teeth (hypodontia)
3. Crowding
4. growth (class III A/P?)
5. higher risk for Caries
61
Outline 5 treatment stages for CLP patients. (5)
* 3 months = Lip closure
- Only closed for aesthetics and social purposes
* 6-12 months = palate closure
- Corrected for when sound/Babble starts
- Newborns obligate nasal breathers can’t close palate before 6 months
* 8-10 years = alveolar bone graft
* 12-15 years = definitive orthodontics
* 18-20 years = surgery (secondary surgeries e.g. orthognathic after growth stops)
62
Name 5 members of the CLP MDT?
* cleft nurse: will see parents within 24 hours
* surgeon
* speech therapist: to assess speech progression
* dental team
* ENT
* Audiologist
* Respiratory/airway consultant
* Geneticist
* Psychologist
63
What are the common complications of orthodontics? (11)
* Decalcification
* Root resorption
* Relapse
* Soft tissue trauma
(above are the most important)
* Recession
* Loss of perio support
* Headgear injuries
* Enamel fracture/toothwear
* Allergy
* Loss of vitality
* Poor/failed tx
64
How is orthodontic relapse managed? (3)
* Case selection – treat the severe malocclusions (accept the mild)
* Informed consent – advise px this commonly occurs and esp in which cases
* Provide retainers – fixed or removable (for life)
Removable retainers:
* Clear occlusal retainer
* Pressure/vacuum
* Essix
* Hawley type
or fixed retainers
(or both)
65
How is orthodontic decalcification managed? (4)
* Case selection of pxs for ortho
- good OH prior to tx, motivated, low caries risk
* Oral hygiene instruction (before and during)
What OHI do we give?
- Minimum 2x per day very thoroughly
- After every meal
- Use disclosing tablets
- Target gingival margins
- Target around each bracket
* Diet advice
- Encourage non-cariogenic diet
- Educate impacts of sugar amounts and frequency
- advise using free gum to stimulate saliva (buffering)
* Fluoride
- Toothpastes
High risk = Can provide 2800/5000ppm toothpastes
Advise use 2x daily and other toothpastes in-between to prevent OD
- Mouthwash 0.05% (225ppm)
Used in-between brushing not after
- Duraphat Vanish (4 monthly)
- F releasing GIC
If oral hygiene is very poor and px very high risk then consider continuing with treatment or consider if the tx should be discontinued and take brackets off.
66
How is orthodontic gingival recession managed? (3)
- Correct tx planning by avoiding overexpansion and keep teeth within the bone.
We need to warn patient of risk of recesion (thin gingival biotype has an increased risk)
If recession is bad-Gingival graft
67
How is orthodontic root resorption managed? (2)
Inform patient prior to treatment -
* Root Resorption is Inevitable (average approx 1mm over 2 years of fixed appliances)
* Severe in 1-5%
* Affected teeth UI>LI>6s
* Any relevant Risk factors:
* Type of movement (Prolonged/high force. Intrusion/ Large movements/torque)
* Root form (Blunt/pipette/resorbed already)
* Previous trauma.
Management-
Radiograph teeth start/during/ end
Fixed retention at end of treatment
Stop treatment short if root resorption is concerning.
68
Apart from relapse/decalcification/ root resorption/ gingival recession.
List other less common complications of ortho treatment.
* Soft tissue trauma
* Enamel fracture/toothwear
* Allergy
* Loss of vitality
* Poor/failed tx
* Periodontal health risk
* Headgear injuries.
69
Lateral ceph
- What are SnA, SNB and ANB?
SNA: SNA relates maxilla to the anterior cranial base
Average value is 81 degrees ( +/- 3)
SNB; SNB relates mandible to the anterior cranial base
Average value is 78 degrees ( +/- 3)
ANB: ANB relates the mandible to the maxilla
Average value is 3 degrees ( +/- 2)
70
What are the average values of SnA, SNB and ANB in Caucasians?
SNA: SNA relates maxilla to the anterior cranial base
Average value is 81 degrees ( +/- 3)
SNB; SNB relates mandible to the anterior cranial base
Average value is 78 degrees ( +/- 3)
ANB: ANB relates the mandible to the maxilla
Average value is 3 degrees ( +/- 2)
71
What is the average FMPA angle in caucasians?
27 degrees
72
What is the average incisor angulation?
109 = uppers
93 = lowers
73
What is the average ANB for Class II and Class III patients?
Class II: ANB relates the mandible to the maxilla
> 5 degrees (increase from average)
Class III: ANB relates the mandible to the maxilla
< 1 degrees or negative
74
Give 4 causes of a diastema.
* Smaller teeth
* 10% associated with Supernumerary tooth which is not interfering with eruption of adult teeth i.e. conical SN
* Missing teeth (hypodontia)
* frenal attachment (High labial frenum)
75
How are diastemas managed?
* Wait for permanent canines to erupt (This will close a diastema of <2.5mm)
* Accept
* Orthodontic treatment- close gap & bonded retainer
* If caused by blockage supernumerary tooth (we could extract the supernumerary - but Risk V benefit.
76
How is a posterior crossbite managed?
We exapnd the upper arch using:
URA with mid-palatal screw and a posterior bite plate. (preventing interference between the lowers and uppers by providing a flat surface to slide the teeth across)
77
Provide 2 ways of expanding the arch.
URA with a midline palatal screw
Quadhelix modification to fixed appliance
78
What teeth are most commonly infra-occluded?
when is this seen?
lower 1st primary molar most common (D)
- commonly occurs if there is congenital absence of premolar
79
How will infra-occluded teeth appear clinically and radiographically?
No physiological mobility
Appear low in the arch
metallic percussive note
Radiographically:
no PDL radiographically
root resorption (ERR).
80
What factors determine the management of infra-occluded teeth? (2)
Presence of a permanent successor:
Yes = observe for 1 year.
No = extract
Height of visible crown
= Tooth should be extracted before there is less than 1mm of crown showing.
81
What are the treatment options for infra-occluded Teeth?
if permanent successor present - monitor for 1 year for eruption
- after this XLA
if no permanent sucessor = XLA
Extract tooth before there is less than 1mm of crown height.
82
Name 4 components of a fixed appliance.
Bracket
orthodontic bands
archwire - NiTi or SS
anchorage component
force generating component e.g. elastic power chains
modules - elastic or self ligating
auxillaries e.g. spring, elastomeric chain, plastic tubing
83
Describe how tooth movement works.
mechano-chemical theory:
Mechanical stress applied to the tooth there are areas compression and tension on the tooth
* Neuropeptides are released from nerve endings
* Neuropeptides stimulate fibroblasts, endothelial cells and alveolar bone.
* Fibroblasts communicate with osteoclasts and osteoblasts
* The activation of the osteoblasts and osteoclasts = alveolar bone and PDL remodelling
- Resorption in areas of compression
- Deposition in areas of tension
------- (Added this answer- felt like above was too much? Xlara)
A light force is applied to the tooth causing frontal resorption and slow movement.
There is hyperaemia within the PDL.
Resorption of the lamina dura from the pressure side (Osteoclasts)
Apposition of the osteoid on the tension side (osteoblasts)
Thereby reorganising the PDL
84
Describe how bodily movement works in fixed appliances. (3)
- Move the tooth whilst maintaining it’s angulation
- Coordinated bone modelling and remodelling: allows resorption on pressure side side and deposition on the tension side.
- Allows tooth to move whilst maintaining a normal relationship with the periodontium
85
Describe what occurs in frontal resorption. (6)
- Hyperaemia in the PDL
- Increased Osteoclasts and osteoblasts activity.
- Lamina dura is resorbed by osteoclasts on the side with pressure applied
- Apposition of osteoid by osteoblasts on the tension side
- PDL reorganises
- Gingival fibres remain distorted (retention needed)
86
Provide 4 methods of anchorage.
Removable apliance
-Baseplate
Fixed apliance
-Transpalatal arch
-Palatal arch with nance button
TAD - temporary anchorage devices
A non osseointegrating mini screw
87
Define overjet
The horizontal distance between the labial surface of the incisal edge of the upper incisors to the surafce of the lower incisors
88
Define overbite
Vertical overlap of incisors.
Average - upper incisors overlaps/covers 1/2 to 1/3rd of lower incisor crown
89
Define molar relationship
class 1: Mesiobuccal cusp of the upper 6 occludes with the buccal groove of the lower 6
Class 2: mesiobuccal cusp Anterior to the buccal fissure/groove
Class 3: Mesiobuccal Posterior to the buccal fissure/groove
90
Define canine relationship
Class 1: The upper canine is posterior to the lower canine
Class 2: The upper canine is anterior to the lower canine
Class 3: The upper canine is very posterior to the lower canine
91
Define crowding
Measure by overlap or space available
mild crowding = 0-4mm
moderate = 4-8mm
severe = 8+ mm
92
Define incisor angulation
This is the relationship of the long axis of the tooth and the alveolar bone:
Angle of Upper Incisors to maxilla (109)
Angle of Lower Incisors to mandible (93)
93
7 year old child presents with impacted 1st permanent molars and crowded lateral
incisors
- Why might a first molar be impacted?
* premature loss of a primary molar (Mesial drift)
* crowding of the arch
* small maxilla (space for eruption is smaller)
* angle of eruption
* ectopic position
* cleft lip and palate
* The morphology of adjacent primary molar
94
7 year old child presents with impacted 1st permanent molars and crowded lateral incisors.
What problems are associated with impacted FPM?(4)
Pulpitis of the E
Premature exfoliation of the E
cyst formation
Caries
95
7 year old child presents with impacted 1st permanent molars and crowded lateral
incisors
Give 5 possible treatment options for an impacted molar?
* Observe for ~6 months:
66% will dis-impact by age 7 but requires good OH to prevent stagnation and caries
* XLA of E:
Regain & maintain space for premolar or treat crowding at later stage
* Separators to disimpact.
* Disc the E (cut it back to dismpact)
* **Orthodontic treatment**-
Band the E & bracket 6 with an open coil.
URA with finger spring & attachment on the 6.
96
7 year old child presents with impacted 1st permanent molars and crowded lateral incisors.
**His mother mentions his primary teeth were straight, what features of normal development should prevent crowding of the permanent dentition?**
* Natural spacing between the primary teeth- allows relief of any crowding in the permanent dentition
* Growth of the maxilla and mandible (increased dental arch creating space for permanent teeth)
* Leeway space (extra mesio-distal space occupied by the primary molars which are wider than the premolars which will replace them- Usually equates to 1.5mm per side on the upper arch and 2.5mm per side in the lower arch)
* Eruption of proclined permanent incisors
* Ugly duckling stage (Distally pointed lateral incisors and a diastema prior to permanent canine eruption)
97
Define leeway space and how does this relieve crowding. ?
Marked difference in size between deciduous and permanent successors – especially canine and premolars.
This relieves crowding as there is more space for the permanent teeth to erupt into:
Maxilla- CDE are 1.5mm wider than 3/4/5
Mandible CDE are 2.5mm wider than 3/4/5.
Take a space requirement measurement at the age of 9
Measure from the mesial of the 6 to the distal of the 2
Ideally > 18.5mm space
98
A child attends with an ecoptic canine.
At what age should you be able to palpate the canines in the buccal sulcus ?
Maxillary canines should be palpable at age 9-11.
99
What is the ideal. age range for interceptive orthdontics treatment of the ectopic canine?
Between 11 (when the canine should be palpable) and 13
100
Name 2 syndromes associated with missing teeth?
Cleft lip and palate.
Anhydrotic ectodermal dysplasia
Down syndrome
Piere robin syndrome.
101
What are the options for hypodontia treatment?
1.Accept (&monitor)
2.Restorative alone
3. Orthodontics alone
4. Cobined orthodontic and restorative treatment
Open gaps & redistribute the space to make room for restorations (implants/ Resin bonded bridge)
Close space
-Simple closure
-Space closure plus (extrusion/intrusion/ rotation)
## Footnote
*
102
Of all the people with missing teeth, how many have missing primary teeth and how many have missing permanent teeth?
Primary <1%
Secondary 5-6%
103
What 3 teeth in order excluding 8s are most commonly missing?
1. Lower 5
2. Upper 2s
3. Upper 5s
104
How can we localise canine position?
Give examples of types of imaging that can be used.
Using parallax
vertical parallax = maxillary oblique occlusal and an OPT
Horizontal parallax = 2x PA's (from different angles)
How to:
when comparing the above 2 images, Consider the movement of the images and establish if its horizontal or vertical
- it to the left or right (horizontal) or is it up and down (vertical)
- fix on a feature that is common to both images
- is this feature moving in the same direction as the beam movement or it it moving in the opposite direction
= PAL comes with or SLOB
105
What are the treatment options for an ectopic canine when the C has already been extracted? (4)
Do nothing and monitor
(If there is crowding - use a passive appliance for space maintenance.
Maxilla (Nance or transpalatal arch)
Mandible (Lingual holding arch)
surgical removal - unfavourable position (too high/close to midline), ERR, pt wishes
surgical exposure (open and closed) and orthodontic alignment
autotransplantation
106
What clinical signs indicate impacted canines? (6)
Delayed eruption of the canine
asymmetrical eruption (> 6 months later the contralateral tooth)
retained c's (can be mobile)
loss of vitality or mobility of 2
discolouration of 2s
kicked out crowns of the 2's
107
What are the dental features of a class III malocclusion? (9)
- Class III incisors
- Often but not always C3 molars
- Often reversed overjet
- Reduced overbites or AOB present
- Crossbites (Ant or post)
- Proclined upper incisors and retroclined lower incisors.
- Gingival recession (Caused by upper incisors heavily occluding on lower incisors lingually)
- Tendency of displacement on closing
- Wear on the labial surface of upper central and lower incisor teeth.
108
What is the definition of a Class II Division II malocclusion?
The lower incisor occludes posterior to the cingulum plateau of the upper incisor and the upper incisors are retroclined
The overjet is reduced but can also be increased
109
What are the dental features of a Class II Division II?
- Retroclined upper centrals and lower centrals
- Upper 2’s crowded, mesio-labially rotated or normal/proclined (depends on their position relative to the lower lip line)
- Reduced arch length = worsens crowding
- class 2 buccal segments
- Thin Laterals have poor cingulum = increased overbite as there is less of an incisal stop
- Increased/deep overbite
- Lower incisors can occlude the upper incisors (posterior to the cingulum plateau) /palatal mucosa
55% have > or equal to 1 dental anomaly; 20% have impacted canines and 15% have microdontia of the lateral incisors
110
What are the treatment options for a C2D2 malocclusion?
1. **Accept**
- Aesthetics acceptable (no significant malocclusion features)
- Patient not concerned
- Overbite not a significant problem i.e. traumatic
2. **Growth modification** (can only use in growing patients)
- Boys 14 (+2)
- Girls 12 (+2)
- Use in mild/moderate skeletal 2 pattern
- Modify the twin block and use to convert C2D2 to C2D1 and then use twin block to achieve buccal segment change, bite reduction and fine tune after with fixed appliances.
Using:
Upper modified twin block:
* E;SA * ELSA Spring (controlled chairside) makes appliance active = procline upper labial segment and procline the retroclined upper centrals
* Midline palatal screw
* Acrylic blocks
* Adams clasps
Lower as normal twin block
3. **Camouflage**
Accept underlying skeletal base relationship and aim for class 1 incisor relationship
- Px no longer growing
- Use in mild/moderate class 2
Uses;
Fixed appliances to;
* Reduce the overbite (will relapse if not corrected)
* Correct the inter-incisal angle
- Palatal root torque the upper incisors
- Proline the lower incisors
= normalises inclination and increases stability
4. Orthognathic surgery
used;
* When the malocclusion is too severe for ortho tx alone px with underlying skeletal discrepancy e.g. AP/vertical etc)
* In patients who have stopped growing
* Profile concerns
111
What soft tissue features may be seen class II div II (5)
High resting lower lip line (secondary to a reduced lower face height)
Lower lip sits higher up on the upper incisor crown = retroclines upper incisors
Lip trap: Upper 2’s have shorter clinical crown height = escape the effect of the lower lip and can trap the lower lip (why they are not retroclined like centrals and flared/prclined instead)
lip trap/tight lower lip = Lower incisors can also be retroclined
Mrpdarked labio-mental fold
Trauma to lower anterior labial ginigvae/palatal mucosa
112
How do we measure the transverse skeletal relationship
Assess asymmetry from in front of the patient and above.
we use the mid sagittal reference line: draw a line down the inter-pupillary line (between the pupils) and down the cupids bow and chin.
113
How do we measure the vertical skeletal relationship? (3)
We use the Frankfort mandibular planes angle (FMPA) - the line from the top of the ear hole to the base of the orbit (frankfort plane) is compared to the mandibular plane.
Average = 27°
UAFH:LAFH → 50:50 clinically. Measure glabella to subnasale and subnasale to menton.
Lateral cephalometry.
114
Name 5 active components, their measurements and uses.
0.5mm HSSW
* palatal Finger springs - used to retract teeth in the line of arch
* Z- spring – push tooth forward into the arch (ant crossbites)
* Flapper spring – push tooth forward into the arch
* T spring - buccal movement of teeth
* midpalatal screw = expand the upper arch
0.5mm HSSW sheated with 0.5mm internal diameter tubing to prevent distortion
* Roberts retractor - Moves teeth back- reduce an overjet
* Buccal canine retractor - retract buccally placed canines back and in.
115
Name 2 retentive components and their measurements
07mm HSSW (0.6mm if on a deciduous tooth/newly erupted tooth)
* Adams
* Southend
* Labial bow
116
Give 2 baseplate modifications
FABP - correcting overbite
(OJ +3mm)
PBP - correcting crossbite
117
17 year old has missing 22 and 23
- What are the options for replacement? (4)
Accept
Restorative - Denture / Resin retained bridge/ space maintain until age for implant
Orthodontics alone- close the gap.
Combined orthodontics and restorative
- Space opening + bridge/implant
- space closure plus & restore leftover space)
118
17 year old has missing 22 and 23.
What problems do you face with the aesthetic? (2)
Missing teeth are at the front of the mouth.
= Psychological impact (bullying/teasing)
= self conscious and may prevent the patient from smiling.
Gap too large for 1 tooth replacement
Gap too small for 2 tooth replacement
119
17 year old has missing 22 and 23.
What problems do you face with function? (4)
No canine- canine guidance.
Difficulting incising/masticating food.
May whistle when speaking .
Teeth may not occlude properly due to the gap
120
17 year old has missing 22 and 23.
The patient wants to get implants.
WHat 3 things should you check first?
* Periodontal condition of the teeth
* Quality and quantity of alveolar bone (we need enough)
* Their existing teeth (We need 7mm of space for an implant)
* MH: bisphosphonates, poorly controlled diabetes etc
121
In which part of the mouth do most supernumerary teeth occur
| 2020 Paper 2 Q33
Anterior maxillary region.
122
A patient wears a Twin-block appliance for 9 months and their overjet is reduced from 10mm to 2mm. List six possible changes that functional appliances can produce to allow this. (3)
| 2020 Paper 2
Retroclination of upper incisors
Proclination of lower incisors
Distal movement of the upper dentition
Mesial movement of the lower dentition.
Restriction of maxillary growth
Encouragement of mandibular growth.
123
Child attends with a 10mm increased overjet. Why should this patient be referred to the orthodontist?
Overjets >9mm trauma is twice as likely
(IOTN 5a)
