MCQ exam Flashcards
4 common orthodontic problems
Crowding
Prominent upper teeth
Missing teeth
Extra teeth
What is malocclusion
An appreciable deviation from the ideal occlusion that may be considered aesthetically or functionally unsatisfactory
3 malrelationships of the arches
Anteroposterior
Vertical
Transverse
What is an anteroposterior arch malrelationship
The mandible is more or less protrusive than the maxilla
Describe a vertical arch malrelationship
The lower part of the face is too short or too long
Describe a transverse arch malrelationship
The face is asymmetrical when viewed from the front
3 common classifications of occlusion
Incisor classification
Skeletal classification
Angle`s classification
Equation for calculating crowding
Crowding = Total tooth size - Total arch length
3 severities of crowding
Mild < 3mm
Moderate 4-5 mm
Severe > 6mm
Describe overjet and what is considered normal
Horizontal relationship between the upper and lower incisors
Normal: 2 - 4 mm
Describe overbite and what is considered normal
Vertical overlap of the upper anterior teeth over the lower
Normal: 3-4 mm
Describe class I incisors
Lower incisor occludes with or lies directly below the upper incisor cingulum
Describe class II division 1 incisors
Upper incisors are proclined, lower incisor edges are palatal to the cingulum plateau of the upper incisors
Describe class II division 2 incisors
Upper incisors are retroclined and lower incisor edges are palatal to the cingulum plateau of the upper incisors
Describe class III incisors
Lower incisor edges lie anterior to the cingulum plateau of the upper incisors
Describe skeletal class I
ANB 2 - 4 degrees: balanced facial profile
Describe skeletal class II
ANB > 4 degrees: profile shows relative mandibular retrusion
Describe skeletal class III
ANB < 2 degrees: profile shows relative mandibular prominence
Describe Angle’s class I
Mesiobuccal cusp of the upper first molar occludes with the anterior buccal groove of the lower first molar
Describe Angle’s class II
The upper arch is at least half a cusp`s width anterior to Class I
Describe Angle’s class III
The upper arch is at least half a cusp`s width posterior to Class I
Describe the Index of Orthodontic Treatment Need (IOTN)
Used to describe need for treatment with an aesthetic and dental health component
Describe the Peer Assessment Rating (PAR)
Used for assessing the quality of treatment outcome
4 common congenitally absent teeth
Mandibular central incisor
Mandibular 2nd premolar
Maxillary lateral incisor
Maxillary 2nd premolar
4 types of supernumerary teeth
Supplemental
Conical
Tuberculate
Odontomes
2 differences of permanent incisors compared with primary
Larger (Mx 7 mm, Md 5 mm)
Greater proclination (10-15 degrees)
3 types of orthodontic appliances
Removable appliances
Fixed appliances
Functional appliances
3 types of removable appliances
Upper removable appliances
Lower removable appliances
Retainers
What is a removable appliance
Orthodontic devices which can be taken out of the mouth by the patient for cleaning
5 removable appliance actions
Tipping
Overbite reduction
Crossbite correction
Extrusion
Intrusion
5 advantages of removable appliances
Simple to use
Less chairside time
Reduced risk of decalcification
Simple to add pontic teeth
Well accepted by patients
4 disadvantages of removable appliances
Limited range of tooth movements
Require more laboratory time than fixed appliances, therefore expensive
Lower removable appliances are uncomfortable
They`re removable
3 components of removable appliances
Active component
Retentive components
Baseplate
6 removable appliances
Anterior / posterior biteplanes
URA - midline expansion screw
Palatal finger spring
Palatal finger spring retractor
Robert’s retractor
Buccal canine retractor
What is a fixed appliance
Devices that are attached to the teeth, cannot be removed by the patient and are capable of causing tooth movement
Forces required for bodily movements
50 – 120g
Forces required for torquing movements
50 – 100g
Forces required for rotational movements
35 – 60g
Forces required for extrusion movements
35 – 60g
Forces required for tipping movements
25 – 60g
Forces required for intrusion movements
10 – 20g
3 advantages of fixed appliances
All types tooth movement possible including bodily movement
Groups of teeth can be moved
Detailed movement possible
6 stages of treatment for straight-wire appliance
- Anchorage management
- Levelling and alignment
- Overbite correction
- Overjet correction
- Space closure
- Finishing and detailing
6 risks of orthodontic treatment
Recession
Root resorption
Pulpal damage
Periodontal ligament damage
Decalcification
Discomfort
5 reasons for orthodontic extractions
Relieve crowding
Reduce an increased overjet
Correct centrelines
Open space for missing teeth
Correct anterior open bite
What is orthodontic anchorage
The source of resistance to the reaction from the active components
What is anchorage loss
Extraction space closes due to forward movement of the anchor teeth rather than those teeth that we wish to move
4 means of providing anchorage
Other teeth
Baseplate on removable appliances
Orthodontic mini-implants
Extra-oral aplliances
2 ways of reducing the demands on the anchorage
Reducing the number of teeth being moved
Limiting the force from the active components to the optimum level for tooth movement (25-50g)
Most common orthodontic extractions in upper and lower arches
Upper arch: 1st premolars, 2nd premolars
Lower arch: 2nd premolars, 1st premolars
6 ideal properties of a retainer
Keep each tooth in its new position
Strong enough
Good aesthetics
Facilitate plaque control
Allow settling to occur
Be removable for eating, cleaning
What is a functional appliance
Appliance that alters the posture of the mandible commonly in the management of Class II malocclusion
5 components of fixed appliances
Brackets
Bands / bonded buccal tubes
Archwires
Ligatures
Auxiliaries
Optimum range of force for producing tooth movement in a single rooted tooth
25-50g
5 orthodontic radiographs
Orthopantomogram (OPT)
Occlusal radiographs
Periapical radiographs
Bitewing radiographs
Cephalometric lateral skull radiographs
4 indications for cephalometric radiography
Descriptive
Treatment planning
Monitoring treatment progress and growth
Growth prediction