Ortho jem Flashcards
Define a class I incisor relationship:
The tips of the lower incisors occlude with or project onto the cingulum plateau of the upper incisors
Define a class II div 1 incisor relationship?
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.
Define Class II div 2 incisor relationship.
The tips of the lower incisors occlude with or project behind the cingulum plateau of the upper incisors. The upper incisors are retroclined.
What is the definition of class III incisor relationship?
The tips of the lower incisors occlude with or project in front of the cingulum plateau of the upper incisors.
What are the basic components of a removable appliance?
Active, retentive, anchorage, base plate.
ARAB
What skeletal pattern do most babies have at birth
Class 2 and as we get older, become more class 3.
What are the primate spaces and where are they?
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.
What would you expect to see when a pt has a digit sucking habit?
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.
How can you stop thumb sucking?
Bitter nail varnish
Educate patient that it will cause issues
Place tape on thumb
Put sock on hand for night time
Class 1 molar relationship:
Upper 1st molar mesio-buccal cusp meets lower buccal groove of 1st lower molar
Class 2 molar relationship:
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)
Class 3 molar relationship:
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.
What is the first permanent tooth to erupt?
First permanent molar at age 6
What is the ugly duckling stage of development?
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.
List 5 advantages of fixed appliances over removable appliances?
Compliance
Rotational movement
Torque movement
Bodily movement
Precise movements
Move more teeth
Ar what age would you initially palpate the upper canines?
10 (or 9.5)
If you were unable to see/palpate the canines at what age would you take a radiograph?
Age 10 (anterior occlusal)
What can be used to locate the canines?
Parallax technique
SLOB
When would you refer a pt with an ectopic canine to the orthodontist for advice?
10
How long does it take for roots to fully form after eruption in permanent dentition?
3 years.
Lat ceph and what is it used to asses?
x
Picture of closing coil different brackets and rectangular wire
Which bracket is which?
- if flat - incisor
- if curved - canine/premolar?
Causes of facial asymmetry?
Mandible to one side? Centre line discrepancy?
Name of function appliances and how they work?
Uses forces created by stretching MoM.
- Twin blocks?
- Bio
- Frankl
- Harvoid
Fixed functions
- Herbst
- MARA
- Advsyn
- Dentsply
Removable appliance functions?
Tips teeth
Space maintenance
Simple tooth movements
Anterior bite plane
Posterior bite plane.
IOTN class 5 components?
x
MOCDO:
Missing tooth
Overjet
Crossbite
Displacement of contact points
Overbite
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.
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.
First order, second order and third order?
x
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.
Anchorage?
x
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
Two types of canine retractor, how they are made and their merits?
x
Two types of springs which can move teeth labially and buccally?
- Labial is Z-spring
- Buccal is T-spring
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).
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.
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
Estimate skeletal pattern from photo
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).
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
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
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!
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)
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).
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
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.
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
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%).
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)?
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
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
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.
When would you particularly check for mandibular asymmetry?
When you see a centre line discrepancy or a posterior cross bite / mandibular displacement.
What is bimaxillary proclination?
Both the upper and lower incisors are proclines.