Ortho jem Flashcards
1
Q
Define a class I incisor relationship:
A
The tips of the lower incisors occlude with or project onto the cingulum plateau of the upper incisors
2
Q
Define a class II div 1 incisor relationship?
A
The tips of the lower incisors occlude with or project behind the cingulum plateau of the upper incisors. The upper incisors are proclined or normal.
3
Q
Define Class II div 2 incisor relationship.
A
The tips of the lower incisors occlude with or project behind the cingulum plateau of the upper incisors. The upper incisors are retroclined.
4
Q
What is the definition of class III incisor relationship?
A
The tips of the lower incisors occlude with or project in front of the cingulum plateau of the upper incisors.
5
Q
What are the basic components of a removable appliance?
A
Active, retentive, anchorage, base plate.
ARAB
6
Q
What skeletal pattern do most babies have at birth
A
Class 2 and as we get older, become more class 3.
7
Q
What are the primate spaces and where are they?
A
Primate space earlier than leeway space.
Upper arch anterior to primary canines.
Lower arch, distal to primary canines.
They give a class 1 canine relationship in the deciduous dentition and prevent overcrowding in the adult dentition.
8
Q
What would you expect to see when a pt has a digit sucking habit?
A
Open bite
Proclined upper incisors
Retroclined lower incisors
Possible asymmetry
Centre-line discrepancy
Unilateral crossbite with displacement.
(tongue will naturally sit lower in thumb-sucking whereas normally tongue will sit in palate creating space for upper arch.
Cheeks will have a negative pressure and push inwards creating a narrow upper arch, unilateral cross bite with displacement.
9
Q
How can you stop thumb sucking?
A
Bitter nail varnish
Educate patient that it will cause issues
Place tape on thumb
Put sock on hand for night time
10
Q
Class 1 molar relationship:
A
Upper 1st molar mesio-buccal cusp meets lower buccal groove of 1st lower molar
11
Q
Class 2 molar relationship:
A
upper 1st molar mesio-buccal cusps anterior to buccal groove lower 1st molar.
Full Class 2 - the MB cusp is in the groove between the lower 5 and the 6.
Half class 2 - cusp to cusp (lower 1st molar to upper 1st molar)
12
Q
Class 3 molar relationship:
A
Upper 1st molar mesio-buccal cusp occludes posterior to buccal groove lower 1st molar.
Full Class III - the MB cusp is the in groove between the lower 6 and 7.
13
Q
What is the first permanent tooth to erupt?
A
First permanent molar at age 6
14
Q
What is the ugly duckling stage of development?
A
At 9/10 when upper 1s and 2s are in but the 3s are yet to come and are sitting near the roots of the 2’s. this causes 2s to flare distally and a diastema may form.
15
Q
List 5 advantages of fixed appliances over removable appliances?
A
Compliance
Rotational movement
Torque movement
Bodily movement
Precise movements
Move more teeth
16
Q
Ar what age would you initially palpate the upper canines?
A
10 (or 9.5)
17
Q
If you were unable to see/palpate the canines at what age would you take a radiograph?
A
Age 10 (anterior occlusal)
18
Q
What can be used to locate the canines?
A
Parallax technique
SLOB
19
Q
When would you refer a pt with an ectopic canine to the orthodontist for advice?
A
10
20
Q
How long does it take for roots to fully form after eruption in permanent dentition?
A
3 years.
21
Q
Lat ceph and what is it used to asses?
A
x
22
Q
Picture of closing coil different brackets and rectangular wire
A
Which bracket is which?
- if flat - incisor
- if curved - canine/premolar?
23
Q
Causes of facial asymmetry?
A
Mandible to one side? Centre line discrepancy?
24
Q
Name of function appliances and how they work?
A
Uses forces created by stretching MoM.
- Twin blocks?
- Bio
- Frankl
- Harvoid
Fixed functions
- Herbst
- MARA
- Advsyn
- Dentsply
25
Removable appliance functions?
Tips teeth
Space maintenance
Simple tooth movements
Anterior bite plane
Posterior bite plane.
26
IOTN class 5 components?
x
27
MOCDO:
Missing tooth
Overjet
Crossbite
Displacement of contact points
Overbite
28
Class II div 2 features?
Tooth features: upper incisors are retroclined and lower incisors are proclined (due to dentoalveolar compensation)
Often sk class is mild class 2. Not often severe (as would be class II div 1)
Chin well developed
Angle of mandible - well developed
Often small lower face heicht
Maxilla is broad and mandible smaller??
Often have premolar scissor bits (premolars outside teeth buccally by one unit)
Lip line is high - ie covering over 3-6mm of upper tooth
Lips compentent
Growth = favourable
Sometimes upper laterals and proclined.
29
Care instruction of removable appliances?
Immediately book appt is removable appliance breaks.
Will ache/may rub - analgesic advise and wax
If any breakages get appointment asap
OH - brush 2 a day. Clean appliance with soap and water (not toothpaste). Take care of parts.
Diet advice - nothing hard or sticky.
Clean after meal
Wear as much as possible (if can while eating) - including night.
30
First order, second order and third order?
x
31
How to bond up ortho brackets?
Check no plaque
Cheek retractor +/- cotton wool, suction
Dry teeth
Etch for 30 secs
Rinse, dry
Bond (don't cure)
Place bracket with bracket holder tweezers with composite on.
Place bracket in centre of tooth (midpoint) and in line with long axis of the tooth.
32
Anchorage?
x
33
Component of URA?
Southend clasp
Adams clasp
Labial bow
Canine retractor
0.8mm for labial bow
0.7mm for southend clasp and adams clasp
0.5 for canine retractor
34
Two types of canine retractor, how they are made and their merits?
x
35
Two types of springs which can move teeth labially and buccally?
- Labial is Z-spring
- Buccal is T-spring
36
Construction of labial bow?
4 functions of labial bow?
Retention of appliance, activation to tip incisors, guidance of canines during retractions, retention of tooth position once tipped/moved).
37
Limitations of removable appliances?
- Aesthetics
- only tip teeth (no bodily movement)
- vertical movements
- lower arch (less sulcus room, trauma, tongue limits lingual space for springs)
- less precision
- can't rotate teeth
- only simple tooth movements
- can't move multiple teeth
- often can cause lateral open bite.
- can't use interarch elastics.
38
How to tell if pt is wearing removable appliance correctly?
Wear facets in acrylic
No problems inserting and removing correctly.
Good speech
Slight gingivitis
Pt comes in wearing it
Active component now passive
Teeth show signs of movement
Oral hygiene is maintained
39
Estimate skeletal pattern from photo
40
Problem with doing ortho in adult pt?
Not aided by growth?
Hard to correct an overbite?
More root resorption?
No growth to help favourable i.e. with class 2 patients
Headgear less acceptable
Often more dental disease (restorations, perio, doubtful teeth prognosis)
Previous treatment
Higher aesthetic demands
Overbite reduction (molar eruption is much slower, bite planes work less well).
41
What is a lateral ceph used to assess?
Anatomical landmarks on lateral ceph?
A-P: skeletal relationship
FMA - facial mandibular plane angle.
SNA and SNB to find ANB angle.
ANB:
- 3.4 = average
- <2 = class 3
- >4 = class 2
Incisal relationship angles
- upper incisal angle (108 +- 5)
- lower indisal angle (92 +- 5)
- interincisal angle (133 =-10)
Sella
Nasion
A and B points
42
Adv and dis of ceramic ortho brackets?
Adv: aesthetics
Dis:
- Can wear teeth on contact (not ideal on lower teeth)
- Harder to remove.
- Still show and elastics stain.
- Prone to fracture
43
Adv and dis of lingually placed brackets and wires?
Adv: aesthetics.
Better bracket design (CAD CAM bases)?
Dis:
Difficult for operator - hard to get teeth perfectly straight.
Uncomfortable
Expensive!
44
Definition of anchorage? What determines it?
Different sources of anchorage?
Resistance which prevents unwanted reciprocal tooth movement.
Root surface area - the rate of tooth movement is related to the level of force per unit tooth root area
Sources:
- Teeth in the same arch
- Teeth in the opposing arch (intermaxillary)
- EO anchorage (headgear)
- Oral mucosa (palate)
- Temporary anchorage devices (TADs)
45
How can you treat a pt with mandibular displacement?
Can treat pt early with URA (tip the upper teeth forward so that they are over the lower incisors).
46
What to do if breaks:
- Fractures of acrylic
- Fractures of the wire
- Midline screw loose
- Soft tissue trauma
- does not fit
- Fractures of acrylic - smooth sharp bits. refer
- Fractures of the wire - remove broken part. keep waring if poss. Refer
- Midline screw loose - advise to stop turning screw. refer
- Soft tissue trauma - cut or adjust wire (OH instructions) refer
- Does not fit - refer
47
Class 1 skeletal pattern:
Class 1 the maxillary dental base sits 2-3mm anterior to the mandibular dental base when the teeth are in occlusion.
48
Class 2 skeletal pattern:
Class 2 the maxilla sits more then 2-3mm in front of the mandible (or mandible lies more then 2-3mm back)
Ie either a retrognathic mandible or a prognathic maxilla or both
49
Class 3 skeletal pattern:
Class 3 the maxilla sits behind the mandible.
Ie either a prognathic mandible (25%) or a retrognathic maxilla (25%) or both (50%).
50
Clinically determining skeletal pattern?
Facial height
Kettles method - fingers with pts head in natural head position.
Facial height you can use the FP line and judge if it lies infront of the occiput (long lower face height or behind (short lower face height)?
51
Which wires for alignment/levelling, and space closure?
Alignment and levelling would be Niti wires (0.014)
Space closure a thicker wire i.e. 20 or 19. 24ss
52
When do girls and boys grow their fastest?
Girls 10-12
Boys 12-14
These are the best times to use functional appliances.
Girls stop growing at 16
Boys stop growing at 18
53
What is dentoalveolar compensation?
When the skeletal base is class 2 or 3, the soft tissues make the teeth into a more favourable class 1 relationship by proclining and retroclining.
54
When would you particularly check for mandibular asymmetry?
When you see a centre line discrepancy or a posterior cross bite / mandibular displacement.
55
What is bimaxillary proclination?
Both the upper and lower incisors are proclines.
56
What is the term for swapping order of the teeth within the arch?
Transposition
Pseudotransposition is just the crowns??
57
What are the causes of a median diastema?
Physiological - ugly duckling stage.
Ethnic/familial
Digit habit - thumb sucking
High labial frenum
Peg laterals
Supernumeraries e.g. mesiodens
Missing teeth (hypodontia_ i.e. laterals
Spaced teeth
Microdontia
Midline pathology
58
What are the causes of AOB?
Digit habit
Long lower vertical face height
MMA angle >32
Tongue thrust - downs syndrome
59
What is mandibular displacement?
When there is significant movement of >1mm from the first initial contact in RCP to final position in ICP.
60
What are the main causes for Class 2 div 1 incisor relationship?
Skeletal class - small mandible
Soft tissue factors - incompetent lips, lower lip is low, digit sucking?
61
What are the essential features of a class 2 div 1 incisor relationship?
EO often incompetent lips, often lower lip is low.
Upper incisors are proclined. Lower incisors lie posterior to cingulum plateau.
Often skeletal class 2 base - can be sever (orthognathic tx)
Vertical and lateral relationship often normal. i.e. Av FMA, no asymmetries.
Maxilla is often large ane the mandible is often small?
Increased risk of trauma! if OJ of >9mm - 44%!
62
What are indications for treating Class 2 div 1 incisor relationship?
If OJ is large - trauma likely so indicated tx to decrease trauma risk
Reduce OB
Aesthetics (don't like teeth sticking out)
Improve function
63
When would you use an upper removable appliance alone?
When there is an OJ of less than 8mm and the upper labial segment is proclined!
Often extract upper 4s and fit URA
64
When would a functional appliance be used in the treatment of a class 2 div 1 incisor relationship?
If there was an OJ of more than 8mm.
Well aligned arches. Crowding! Class 2 molar relationship (FA would bring the lower molars forward!)
When still growing i.e. during the growth spurt (10-12 g, 12-14 b)
65
What are the main indications for fixed appliance?
Want to have torque control of the upper incisors, needed to prevent incisor retroclination
Multiple tooth movement
Bodily movement
Rotation correction
Space closure
Arch coordination (ie.e irregular arch alignment)
66
How does orthognathic surgery worth for severe class 2 relationship?
Tooth movement alone cannot achieve aims.
Would need to do a bilateral sagittal split osteotomy to advance the mandible.
67
What are treatment options for class 2 div 2 cases?
Accept the incisor relationship is class 2 div 2, not severe and not traumatising OB. Pt understands the limited tx objective (maybe just align laterals?)
Correct the incisors to Class 1. And correct OB (easier in growing child)
Change the inter-incisal angle to 135 (so its stable)
Headgear than fixed?
or XLA then fixed?
Or functional then fixed?
68
What is the main aetiological factor in class III?
Sk class 3 (i.e. mandible prognathic, maxilla retrognathic or both)
Facial growth factors, soft tissue factors, occlusal factors.
69
What features are favourable for treatment of class III?
A forwards mandibular displacement is favourable but must be treated early. AS can damage the teeth/periodontium.
Mild class 3 skeletal relationship or class 1
Little or no dentoalveolar compensation
Small or increased OB (i.e. better than AOB)?
70
Why do class 3 patients often have posterior cross bites?
Due to large mandible vs small maxilla (i.e. the skeletal class means that broad parts of the lower meet with narrow parts of the maxilla).
71
What % of patients have impacted canines?
2-3%??
72
What other dental features warn you of an increased chance of ectopic canines?
- Not palpable at aged 10 in the buccal sulcus
- Cs are not mobile
- One 3 has erupted >6 months before
- Missing lateral incisor
- Peg shaped lateral incisors
73
What should you do if you can't palpate the canines buccally by age 10?
Radiographs - parallax and refer
74
What interceptive measures are available for ectopic canines and when are they indicated?
- Do nothing and review in 3 3 to 6 months?
- Extract Cs and wait?
- Extract Cs and Open exposure 3
- Extract Cs and closed exposure - attach chain to fixed appliance?
- Expose and align (leave to erupt for 8-12 weeks, traction, fit URA/fixed appliance) - ???
- Create space and replace with implants, bridge?
- Extract, unfavourable position, crowded, poor prognosis, resorption risk.
- Transplant - rarely done. Poor long-term prognosis. Would leave space and transplanted tooth may ankylose.
75
What factors should be taken into account when deciding whether or not to expose and align an impacted canine?
Is it in a favourable position
Is the patient motivated
Is there enough space for it for come down?
Traction etc . 8-12 weeks for canine to come down.
76
Why are teeth removed in orthodontics?
Due to crowding
To help alter a malocclusion (ie correct incisor OJ)
For anchorage (to create resistance to unwanted orthodontic tooth movement).
77
What main factors that influence the choice of teeth to be extracted?
- Its dental health
- Stability - don't want to alter lower incisor AP position?
- Amount of space needed and where (i.e. anteriorly 4s over 5s?)
- Aesthetics - don't want to take out anterior teeth
78
What are the sequence of steps for planning extractions?
- Plan the lower first
--> crowding? where? assess the tie breaker factors to decide each category of crowing - i.e. canine angulation, lip prominence (do we do XLAs?), initial incisor inclination)
- then the upper arch, usually needs same if not more room
79
what is a functional appliance?
how can they be classified?
how does it work?
An appliance that utilises forces generated by stretching the muscles and soft tissues to produce tooth movements.
Myodynamic (MoM) stretched creating forces on teeth for movement? i.e. stimulate MoM to get forces, posture mandible) and Myotonic (soft tissues elastic recoil - forces teeth to move?)
Dentoalveolar affects = main - tip teeth and move molars and decrease OB
- skeletal effects during growth! + mm mandible -1mm maxilla
- Soft tissues
80
What age should functional appliances be used?
During puberty growth spurt - so around 11-13 (10-12g, 12-14b)
81
What malocclusion can be used to treat using functional appliances?
Class 2 div 1. could do Class 2 div 2 if make it to div 1 first.
Maybe for class 3
82
What are examples of functional appliances?
The clark twin block, bionator, frankl, harvold.
Fixed functions: herbst, MARA, dynamax, advansync.
83
How can tx be monitored using functional appliances?
Review that they are wearing it - i.e. wear marks. Easy in and out. Good speech. Come in wearing it. Mild gingivitis.
There should be a 1mm OJ reduction per month.
Has the molar relationship improved.
Check that you don't need to reactivate.
Lateral open bites may appear.
84
Will be problem bet better as is grown? (Class II? Class III?)
Class II - yes
Class III - no - worse.
85
How you manipulate jaw growth?
By around 1mm with function? Mandible not amenable to growth modification though.
Can slightly restrain maxilla growth with headgear!
86
What is orthodontic anchorage?
The resistance prevents unwanted reciprocal tooth movements.
87
What are the difference sources of orthodontic anchorage?
Teeth in same arch
Teeth in opposing arch (intermaxillary)
Oral mucosa - palate
EO anchorage - headgear
Implants or TADs (Temporary Anchorage Devices)
88
What is excessive loss of anchorage?
Unwanted movement of the anchor teeth during tx to an extent which prevent desired tooth movements being achieved.
e.g. take out a premolar - and anterior and posterior both move into the space - meaning still got an overjet as posterior teeth took half the space.
89
how do we conserve anchorage?
use small forces.
planning
Make sure the anchors have a larger tooth root SA?
Use headgear?
90
What is the spring of choice for retracting a canine?
Palatal retractor.
0.5 size wire
91
What size wire is a labial bow?
0.8mm
92
Why do we use an anterior biteplane?
When we want the posterior teeth to grow together i.e. to reduce an OB anteriorly.
93
What do we use a posterior biteplane?
When we want the anterior teeth to grow together. I.e. to reduce an AOB.
94
How often do we ask the patient to turn a screw?
Once a week (0.25mm activation?)
95
What do we tell a patient when we fit a removable appliance?
Reassure that we will expect aching for 3 days.
Have a lisp for 48 hours.
Eating will be odd for a week.
Wear full time/at night.
Clean with soap and water.
Rinse after meals.
Avoid sticky or hard foods.
Return if fracture.
96
How do we tell if someone is wearing their URA?
Wear to appointment.
Can put in and take out easily.
Not excessive salivation
Teeth are moving.
Good speech.
Signs of wear.
Palatal gingivitis.
Springs are passive (i.e. teeth moved).
97
What IOTN score does someone need to qualify for NHS treatment?
DHC 4 or 5
DHC 3 + AC of 6+
98
What is the basis of PAR scoring?
Features are given certain scores. Measure the overall occlusal irregularity (want to see a % change in Par score) i.e. orthodontist can be judged on their PAR score.
99
What are limitations of IOTN?
Does not assess complexity of treatment needed.
DHC evidence = incomplete.
AC is subjective.
100
What are limitations of PAR indices?
Hypodontia is not given a high score.
Facial improvement is not assessed i.e. for orthognathic patients.
Ectopic canines don't have high score.
101
What is IOTN 5a?
Increased overjet greater than 9mm
102
What is IOTN 5i?
Impeded eruption of teeth (except for third molars) due to crowding, displacement, the presence of supernumerary teeth, retained deciduous teeth and any pathological cause.
103
What is IOTN 5h?
Extensive hypodontia with restorative implications (more than 1 tooth missing in any quadrant) requiring pre-restorative orthodontics.
104
What is IOTN 5m
Reverse overjet greater than 3.5mm with reported masticatory and speech difficulties
105
What is IOTN 5p?
Defects of cleft lip and palate and other craniofacial anomalies.
106
What is IOTN 5s
Submerged deciduous teeth.
CONVENTION: Not recorded unless only two cusps remain visible and/or adjacent teeth are severely tipped towards each other and closely approximated.
107
What is IOTN 4h?
Less extensive hypodontia requiring pre-restorative orthodontics or orthodontic space closure to obviate the need for a prosthesis.
108
What is IOTN 4a?
Increased overjet greater than 6mm but less than or equal to 9mm.
109
What is IOTN 4b?
Reverse overjet greater than 3.5mm with no masticatory or speech difficulties.
110
What is IOTN 4m?
Reverse overjet greater than 1mm but less than 3.5mm with recorded masticatory or speech difficulties.
111
What is IOTN 4c?
Anterior or posterior crossbites with greater than 2mm discrepancy between retruded contact position and intercuspal position.
112
What is IOTN 4l?
Posterior lingual crossbite with no functional occlusal contact in one or both buccal segments.
113
What is IOTN 4d?
Severe contact point displacements greater than 4mm.
114
What is IOTN 4e?
Extreme lateral or anterior open bites greater than 4mm.
115
What is IOTN 4f?
Increased and complete overbite with gingival or palatal trauma.
116
What is IOTN 4t?
Partially erupted teeth, tipped and impacted against adjacent teeth.
117
What is IOTN 4x?
Presence of supernumerary teeth.
118
What is IOTN 3a?
Increased overjet greater than 3.5mm but less than or equal to 6mm with incompetent lips.
119
What is IOTN 3b?
Reverse overjet greater than 1mm but less than or equal to 3.5mm.
120
What is IOTN 3c?
Anterior or posterior crossbites with greater than 1mm but less than or equal to 2mm discrepancy between retruded contact position and intercuspal position.
121
What is IOTN 3d?
Contact point displacements greater than 2mm but less than or equal to 4mm.
122
What is IOTN 3e?
Lateral or anterior open bite greater than 2mm but less than or equal to 4mm.
123
What is IOTN 3f?
Deep overbite complete on gingival or palatal tissues but no trauma.
124
how can fixed braces decrease the OB?
???
125
Can fixed appliances intrude teeth?
Yes
126
What percentage or population. have an ectopic maxillary canine?
2-3%
127
What percentage of population have a mandibular ectopic canine?
0.3%
128
What incisor class is most likely to give a lower face height?
Class 2 Div 2
129
What class is most likely to have a premolar scissor bite?
Class 2 div 2
130
What class is most ilkley to have incompetent lips?
Class 2 div 1
131
What can you use to reduce overbite in children and adults?
Children - Anterior bite plane - functional appliance?
Adults - fixed as not growing and less compliant?
132
What should you look for in class 3 patients that means you treat them early?
Mandibular displacement!
133
What size and type of wire do you use for space cloasure?
SS rectangular.
134
Dilaceration of a root can cause what for upper centrals?
Failure to erupt
135
What is important to remember on an occlusal?
To get the correct LHS and RHS!
136
Can you place elastics on removable appliances?
NO!! they will be pulled out
137
For Class 3 where would you place elastics?
Lower canine region to upper molars.
138
things to learn!
- Qus on uses of removable and fixed
- Learn how to fix overbites - using removable or fixed
- Orthognathic surgery - use of fixed appliances BEFORE surgery - decompensate.
