Ortho Flashcards
What incisor relationship is this?
Class I
What type of tooth movement is this?
Torque
What is a class II molar relationship?
the buccal groove of the mandibular first permanent molar occludes anteriorly to the mesio-buccal cusp of the maxillary first permanent molar
What is the average MMPA?
27 degrees
What does 5p mean on IOTN?
Cleft lip/palate
What are the different types of springs in removable orthodontic appliances?
● palatal finger springs
● buccal canine retractors
● z springs (incisors)
● t springs (premolars)
What is the baseplate of removable orthodontic appliances made from?
Acrylic
What is the Sella (S)?
the point in the midpoint of the sella turcica
What is the gonion (Go)?
the constructed point of intersection of the tangents of the ramus plane and the mandibular plane. This is the most posterior and inferior part on the angle of the mandible
What does the SNA angle show?
Indicates the relative antero-posterior positioning of the maxilla in relation to the cranial base
What does frankfort mandibular plane angle (FMPA) measure?
Growth of the mandible. The angle is the point at which the line of the mandible meets the facial plane (line that goes through the ear canal
What space requirement means orthodontic extractions will be necessary?
More than 8mm space required
What is the B point on a lat ceph?
deepest concavity on the mandibular symphysis (can change with growth and tooth movement)
What incisor relationship is this?
Class II div 1
How often do aligners need to be worn?
22 hours a day
What class skeletal pattern does this patient have?
Class II
What are the main medical contraindications for orthodontic treatment?(5)
● Risk of infective endocarditis
● Asthma (bring inhaler to apt)
● Allergies (latex and nickel)
● Bleeding disorders (complications with orthodontic extractions)
● Epilepsy (damage to appliance and Phenytoin can cause gingival hyperplasia)
What does a 5h IOTN score mean?
Two or more teeth missing from one quadant
What are the two main active components used in removable ortho appliances?
Screws and springs
What kind of bite is this?
Scissors bite
What does 3f mean on IOTN?
Deep/complete overbite but no trauma
What is a class II div 2 incisor relationship?
Lower incisor edges occlude behind the cingulum plateau of the uppers and the upper incisors are retroclined
What is average FMPA?
If the FMPA goes through the base of the head (occipital bone), it is is average
What is the average incisor inclination for maxillary incisors (line through incisors and intersect with ANS-PNS line)?
110 degrees
What type of tooth movement is this?
Pure tipping
What wire is used for southend clasps?
0.6-0.7mm
What does 4c mean on the IOTN scale?
crossbite with mandibular displacement>2mm
What does it mean if the MMPA is greater than 27 degrees?
Indicates vertical bone growth
What does it mean if the SNB angle is less than 80 degrees?
Retrognathic mandible
What is the treatment for retained deciduous theeth?
These teeth usually require extraction if it is due to ankylosis as this can deflect the permanent successor. If the permanent successor is missing, the tooth is often left in situ
What does IOTN stand for?
Index of Orthodontic Treatment Need
What growth phase does a patient need to be in for a functional appliance?
Pre-adolescent (younger than 14 years)
What type of tooth movement is this?
Translation
What does it mean if the ANB angle is greater than 2 degrees?
Class II skeletal pattern
What does it mean if the incisor inclination angle is less than 110 in maxillary or 90 in mandibular incisors?
Incisors are retroclined
What does the S-N line on a lateral ceph show?
Cranial base
What does 4d mean on the IOTN scale?
Displacement (mesial of one tooth to distal of adjacent tooth) >4mm
What is the force applied on a tooth with a spring in a removable orthodontic appliance?
Does not exceed 25-40 grams per tooth
What does 4f IOTN mean?
Traumatic overbite
Why do springs in removable orthodontic appliances need to be close to the gingival margin?
To prevent over-tipping of the teeth
What is the average incisor inclination for mandibular incisors (line through incisors and intersect with Me-Go line)?
90 degrees
When is crowding mild?
When it is 0-4mm (distal from one tooth to mesial of adjacent tooth)
What does it mean if the MMPA is less than 27 degrees?
Indicates horizontal bone growth
What is a class I incisor relationship?
Lower incisor edges occlude on the cingulum plateau of the uppers
What does 3d mean on the IOTN scale?
Displacement (mesial of one tooth to distal of adjacent tooth) between 2-4mm
What is the closed exposure technique for impacted canines?
Gold chain (expose the tooth, place bracket and gold chain and force eruption)
What is the average ANB angle?
2 degrees
What is the A point on a lateral ceph?
deepest midline concavity on the anterior maxilla (can change with growth and tooth movement)
What space requirement means orthodontic extractions may be necessary?
4-8mm space required
What does it mean if the SNA angle is greater than 82 degrees?
Prognathic maxilla
What is a functional appliance?
An appliance that stretches the muscles of mastication, which alters the posture of the mandible
What is a class II molar relationship?
the buccal groove of the mandibular first permanent molar occludes posteriorly to the mesio-buccal cusp of the maxillary first molar
What does it mean if the SNA angle is less than 82 degrees?
Retrognathic maxilla
What are springs in removable orthodontic appliances made from?
0.5 or 0.7mm stainless steel wire
How much does one quarter turn of a screw separate a removable orthodontic appliance?
0.25 mm
What does it mean if the ANB angle is less than 2 degrees (or is negative)?
Class III skeletal pattern
What does 5m mean on IOTN?
Reverse overjet>3.5mm
What clasps are used for retention for premolars and molars in a removable orthodontic appliance?
Adams’ or delta cribs
What can screws in removable orthodontic appliances do?
expansion or distalation (moving teeth more distal)
What clasps are used for retention for incisors in a removable orthodontic appliance?
Southend (m shaped) and C clasps (n shape)
What does it mean if the incisor inclination angle is greater than 110 in maxillary or 90 in mandibular incisors?
Incisors are proclined
What is a normal canine relationship?
when the upper canine sits between the lower canine and the premolar (this is class I)
Name this appliance
Twin block
Which teeth would you NEVER extract for orthodontic reasons?
Upper centrals and lower canines
What is overbite?
The vertical overlap of teeth
What does 2d mean on the IOTN scale?
Displacement (mesial of one tooth to distal of adjacent tooth) between 1-2mm
What orthodontic features will you see on digit suckers and nail biters?
● proclined upper anteriors
● retroclined lower anteriors
● buccal segment crossbites
● reduced overbite or anterior openbite
What is the Pogonion (Pog/Pg)?
the most anterior part of the mandibular symphysis
What does it mean if the SNB angle is greater than 80 degrees?
Prognathic mandible
What is the average SNB angle?
80 degrees
How much of the undercut do Adams clasps need to engage?
At least 1mm
What incisor relationship is this?
Class III
What percentage of impacted canines erupt after interceptive treatment (removing the Cs)?
78%
What is a class III incisor relationship?
Lower incisor edges occlude in front of the cingulum plateau of the uppers
What patients are ideal for functional appliances?
● mild to moderate overjet (up to 11mm)
● increase in overbite
● active facial growth
● willingness to comply
What does 4L mean on the IOTN scale?
Scissors bite
What size diastema rarely requires treatment?
less than 3mm
What percentage of 6 year olds have midline diastemas?
98%
What is the MMPA?
If you extend the ANS - PNS line and Me- Go line posteriorly, you will find a point where they intersect. This angle is called the maxillo-mandibular plane angle (MMPA) - basically the intersection of the maxillary and mandibular plane
What incisor relationship is this?
Class II div 2
What is the acronym for the dental component of IOTN?
MOCDO
missing, overjet, crossbite, displacement, overbite
What is the Nasion (N)?
the most anterior point of the fronto-nasal suture
What is the menton (Me)?
the most inferior part of the mandibular symphysis
What does the SNB angle show?
It indicates the relative antero-posterior positioning of the mandible in relation to the cranial base
What does 4h stand for on the IOTN scale?
One tooth is missing from one or more quadrants
What is the average SNA angle?
82 degrees
What does 4e, 3e, 2e mean on IOTN?
Anterior openbite (depending on size - use IOTN ruler)
What is a class I molar relationship?
the buccal groove of the mandibular first permanent molar should occlude with the mesio-buccal cusp of the maxillary first molar (normal relationship)
What space requirement means orthodontic extractions wont be necessary?
0-4mm space required
What is a balancing extraction?
extracting the contralateral tooth and is mostly done if there is concern of a centre line shift during the eruption of the permanent incisor
Is this patients frankfort mandibular plane angle increased or decreased?
Decreased - past the back of the head
What type of tooth movement is this?
Controlled tipping
What does the MMPA show?
Growth pattern
What archwire is used for the major tooth movement stage of active fixed ortho treatment?
Stainless steel that are rigid and resist deformation
What are the four components to a removable orthodontic appliance?
active components, retentive components, anchorage and base plate
When is crowding moderate?
When it is 4-8mm (distal from one tooth to mesial of adjacent tooth)
What teeth are most likely to have an affect on centre line shift?
Cs and Ds
When is crowding severe?
When it is 8+mm (distal from one tooth to mesial of adjacent tooth)
What is the average space between the distal of the 2 and mesial of the 6 that is needed so there is enough space for all other teeth to erupt?
21mm
What is a class II div 1 incisor relationship?
Lower incisor edges occlude behind the cingulum plateau of the uppers and the upper incisors are normally inclined or proclined
How often should removable orthodontic appliances be worn?
24 hours a day
What does 5s mean on IOTN?
Submerging deciduous molars
What does 5i mean for IOTN?
. If the patient has retained deciduous canines or any impaction/impeded eruption
What class skeletal pattern does this patient have?
Class III
How regularly should a patient adjust a screw in a removable orthodontic appliance?
every week
What are the 6 different types of removable orthodontic appliance?
● interceptive (move teeth)
● space maintaining
● pre-surgical orthopaedics (cleft care)
● active plate
● retainer
● functional appliances
What may cause submerging deciduous teeth?
Ankylosis, no permanent successor or idiopathic
What are the three stages of active fixed appliance treatment?
- Levelling and aligning
- Major tooth movement - overjet/overbites, space closure, centre line correction
- Finishing - detailed alignment
Is this patients frankfort mandibular plane angle increased or decreased?
Increased - meets before the back of the head
What is the go-to tooth for orthodontic extractions?
First premolars
What class skeletal pattern does this patient have?
Class I
What does the ANB angle show?
The relative position of the maxilla and mandible to each other
What wire is used for Adams’ and Delta cribs?
0.6-0.7mm round wire
What is the difference between Adams and delta cribs?
Delta makes a little loops and Adams makes more of a v shape on the mesio and disobuccal surface of the clasp
What is a compensating extraction?
Removing the opposing tooth to avoid overeruption
What kind of bite is this?
Normal
What does a 5a mean on the IOTN scale?
Overjet>9mm
When would you remove a lower incisor for orthodontic extractions?
In cases of class III occlusion or when lower incisor crowding is the only problem
What stage of active fixed appliances are NiTi wires used for?
Aligning
What is the method for treating crown root dilaceration?
Gold chain usually
What kind of bite is this?
Buccal bilateral
