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BDS3 University of Adelaide Dentistry > Orthodontics > Flashcards

Orthodontics Flashcards

1
Q

What are the 4 types of functional reasons for orthodontics?

A
  1. Increased Overjet
  2. Crossbites
  3. Labial Crowding in lower incisor areas
  4. Traumatic Overbite
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2
Q

What is the Gnomic Growth Pattern?

A

Growth occurs in a sunburst “explosion” pattern centred at the Pt point (inferior point of pterygomaxillary fissure)

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3
Q

According to Scammon’s Growth Curve, which system has peak growth in teenage years?

A

Genital

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4
Q

What is the Cartilage theory of craniofacial growth (Scott 1950) and why is it not current dogma?

A

Cartilage is primary determinant of skeletal growth and bones respond secondarily and passively

Debunked: Transplantation: some cartilage types (epiphyseal) grow, others (secondary cartilage, eg condylar) don’t

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5
Q

Where is the Pogonion (Pog)?

A

Soft tissue landmark - the most anterior point of the mandibular symphysis

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6
Q

What is Dental Arch Length?

A

Anterior/Posterior distance from central incisors to most distal point of permanent molars

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7
Q

What molar relationship is likely to occur for a mesial step that is less than 1mm?

A

76% Class I
23% Class II
1% Class III

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8
Q

What sort of chin is often portrayed in culture?

A

Prominent class III seen in superheros such as superman.

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9
Q

What are limitations of Ackermann-Proffit?

A

Static Analysis
No Aetiology
Little value if group number used - specifics needed
Only Profile used: neglected full face and smile views (mini-aesthetics)

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10
Q

What is required to stimulate chondrocytes to secrete cartilage in the condylar cartilage

A

Functional loading stimulates mesenchymal cells to proliferate and grow, ultimately differentiating into chondrocytes which secrete cartilage

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11
Q

What is primary crowding?

A

Primary Crowding: an inherent discrepancy between tooth size and the available arch length (jaw/ apical base size).

This is primarily determined by genetic origin

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12
Q

What are different direct measurements that can be used to gauge growth and development?

A
  1. Anatomical Measurements
  2. Hand Radiograph
  3. Secondary Sexual Characteristics (not really used in orthodontics)
  4. Lateral Cephalometry (including cervical maturation staging)
  5. Clinical Laser Scanning
  6. 3D Finite Element Model
  7. MRI
  8. CT Scanning
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13
Q

What is the emergence timing for primary dentition?

A 
6-7 months Lower As
7-8 months: Lower Bs and Upper As
9-10 months: Upper Bs
12-14 months:  Ds
16-18 months: Cs
24-30 months: Es
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14
Q

What is the embryological origin of the mandible?

A

1st Pharyngeal Branchial Arch: cells in the centre of the mesenchymal core differentiate into chondrocytes and form the arch cartilage

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15
Q

What is the main determinant of tooth position of accessional permanent teeth?

A

Skeletal growth of the maxilla + mandible + apical base

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16
Q

What is Traumatic Overbite?

A

Where the lower incisors traumatise the palatal gingiva in the upper arch to cause inflammation

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17
Q

Does Lip Separation increase/decrease with age?

A

With age: reduction of lip separation (incompetence) due to lower lip elevation

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18
Q

What factors predispose the possibility of root resorption during orthodontic movement?

A

Root shape

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19
Q

What is Bimaxillary Proclination (bimaxillary dentoalveolar proclination)?

A

Where both upper and lower incisors are proclined. This will coincided with reduced overbite and is often seen in ethnic variations

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20
Q

Why does the N angle change during growth?

A

Nasal Dorsum (the hump) can grow by 1mm/year during adolescence, changing the N angle by up to 30 degrees during peak growth period

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21
Q

What is Ackerman-Proffit Skeletal Class III?

A

Mx retrusive relative to Md

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22
Q

What are the two mid-sagittal sutures in the cranial base and where do they run from?

A

Anterior Cranial Base (ACB): Nasion to Sella Turcica – nasomaxillary attached

Posterior Cranial Base (PCB): Sella Turcica to Barium –Md indirectly attached

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23
Q

What is Class I Flush Terminal Plane relationship?

A

Flush relationship of Mx/Mn Es and where Mx C tip is distal to the tip of the Mn C.

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24
Q

What are the 6 categories of the Ackermann-Proffit Classification System?

A
  1. Alignment (Teeth via Lischer)
  2. Profile (Facial Aesthetics) Involves all soft tissue
  3. Types (Transverse relationship)
  4. Angle’s Classification (Sagittal AP relationship)
  5. Bite Depth (Vertical relationship)
  6. Overlapping Problems
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25
Q

What gives the chin it’s prominence with regard to the mandibular dento-alveolar ridge?

A

Prominence of chin results from relative lingual anterior movement of mandibular incisors at B point

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26
Q

What is a lateral ceph landmark that can be used to gauge malocclusion in the absence of an upper FPM?

A

Key Ridge - the anterior surface of the zygomatic process of the maxilla

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27
Q

What is Bjork Class Postnormal Occlusion?

A

Class II Occlusion - where the mandibular 1st molar is more than one-half cusp posterior of pre-normal relation

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28
Q

What molar relationship is likely to occur for a mesial step that is more than 2mm?

A

68% Class I
13% Class II
19% Class III

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29
Q

Which facial profile has natural divergence?

A

Straight Profile

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30
Q

How is Bolton’s Analysis calculated?

A
  1. Measure mesio-distal width of teeth 6-6 in both arches
  2. Record the combine widths of the Mn vs Mx for:
    - Entire arch 6-6
    - Anterior segment 3-3
  3. Total Arch size is plotted on a 2 different X/Y axis graphs (entire arch & anterior segment) to calculate Bolton’s Discrepancy for both measurements
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31
Q

When does the condylar cartilage initially develop?

A

12 weeks in utero - after initial ossification of the mandible has begun

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32
Q

Where is the Nasion (N)?

A

Soft tissue landmark - The intersection of frontal and two nasal bones. Visible depression directly between the eys, superior to the bridge of the nose

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33
Q

What’s the difference between Infraposition and Infraocclusion?

A

Infraposition: alveolar bone growth stops from ankylosed tooth (from trauma). Notably the gingival level is more apically placed

Infraocclusion: tooth has not reached occlusal level

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34
Q

What 3 anatomical structures develop from Meckel’s Cartilage?

A
  1. Symphyseal cartilage: from Medial tip (portion closest to where two Md articulate)
  2. Sphenomandibular ligament: from Mid portion
  3. Malleus and incus: from Lateral portion
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35
Q

What preventative measures need to occur for an excessive overjet

A

Mouthguards worn during physical activity

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36
Q

How is leeway space eventually lost?

A

Mesial drift of the FPMs after the eruption of permanent canine and premolars

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37
Q

What tooth sizes are aesthetic in the anterior zone?

A

Decreasing size from the central > lateral > canine following the golden proportions

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38
Q

What is Foster and Hamilton Class I Occlusion?

A

Opposing 2nd molars are the same (flush) vertical plane in centric occlusion

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39
Q

What is Bolton’s Discrepancy?

A

Insufficient/Excessive Mn vs Mx size ratio outside of normal

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40
Q

What is the main direction of tooth eruptive force?

A

Axial. Other planes of force can occur, resulting in tooth tilting/drifting

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41
Q

Which tooth is most likely to be ectopicly placed?

A

Upper canines

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42
Q

What are the cranial base synchondroses?

A

Cartilaginous Junctions between bones in the cranial base that allow for active growth via endochondral ossification.

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43
Q

Which facial profile occurs when the Vertical G’-Sn-Pog’ line slopes posteriorly with Pog posterior relative to glabella in sagittal plane?

A

Convex Profile (Posterior Divergence)

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44
Q

T/F: Men have a higher lip line then women

A

False, women tend to display 1-2mm more gingiva than males and this is more acceptable aesthetically

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45
Q

Where is Rhinion (R)?

A

R: Rhinion: junction of hard tissue nasal bone and septal cartilage

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46
Q

What does Cephalometric Superimposition require?

A

Time series of patient’s Lat Ceph radiographs

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47
Q

What trends can be seen in growth curves between males and females?

A

Amplitude: males at a high rate Duration: males for longer
Onset: females start earlier but don’t grow as much

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48
Q

What should you expect to see clinically for permanent canines at age 10?

A

Developing tooth can be palpated on the buccal sulcus

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49
Q

Is Mandibular Prognathism likely to resolve without treatment?

A

No

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50
Q

Which finger is missing the intermediate phalanges?

A

Thumb

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51
Q

What are the 5 key sutures in the naso-maxillary complex?

A 
Frontomaxillary 
Zygomaticomaxillary
Pterygomaxillary 
Zygomaticofrontal (Indirectly)
Zygomaticotemporal (Indirectly)
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52
Q

Which teeth are most likely to be transpositioned?

A

Maxillary 3 and 4

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53
Q

What features do you expect to see in a skeletal neutrocclusion (Class I)?

A

Overbite 20-30%
Overjet 2-3mm
Class I Canine Relationship
Class I Molar Relationship

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54
Q

What are some weird trends in dental aesthetics?

A

Yaeba (snaggle teeth) proclined canines
Diastemas (increased frequency in fashion)
Cape Flats Smile - missing anterior maxillary due to violence. So gangsta
Ritualistic Tooth Filing

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55
Q

According to Scammon’s Growth Curve, which system peaks at 10 years and then declines?

A

Lymphoid

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56
Q

What should you expect to see clinically for permanent canines at age 12?

A

Indicative of late eruption - investigate clinically and radiographically whether the tooth is not present/impacted

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57
Q

Is a skeletal class II in a baby a concern?

A

Not really, mandibular growth will be faster than maxillary growth and in most cases compensate in late teens to 25. However check for familial skeletal patterns.

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58
Q

What is primate space?

A

Gap spaces in the arch of primary dentition

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59
Q

What are different types of growth estimation and which one is appropriate for growth estimation?

A

Skeletal Bone Ossification: marker of skeletal maturity during puberty growth spurts
Dental: Tooth formation and emergence
Age: deviations from medium
Height: heavily influenced by environment/diet
Weight: heavily influenced by environment/diet
Sexual Maturity
Neural Coordination - Not present in all people
Neural Cognitive development - differences between sexes

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60
Q

Where is the Glabella (G)?

A

Soft tissue landmark - The smooth part of the forehead above and between the eyebrows

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61
Q

How can malocclusion be described in Angle’s line of occlusion?

A

A tooth being either lingual/labial from the line of occlusion

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62
Q

What is the Ugly Duckling phase?

A

The transitory stage of dental development (7-12 years) before the eruption of permanent canines, when there is lateral tipping of incisors causing a “ugly appearance

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63
Q

What is a Angle’s Class I Classification?

A

MB cusp of upper first molar is received in lower first molar buccal groove where there are malocclusion features such as crowding/rotation

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64
Q

What are the different types of forwards rotators?

A

Type I: Point of rotation around the condyle
Result: reduced lower face height

Type II: Point of rotation located at incisal edge of lower incisors
Result: marked development of posterior face height and normal anterior face height

Type III: Point of rotation at level of pre-molars
Result
Large overjet/reverse overjet
Anterior face height underdeveloped
Posterior face height increases with deep bite

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65
Q

What are the important stages of the Nolla Calcification Staging?

A 
Stage 0: Absence of Crypt
Stage 2: Initial Calcification
Stage 6: Crown complete
Stage 9: Root Complete, Apex Open
Stage 10: Apical Foramen Closed
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66
Q

T/F: Growth of the cranial base is primarily due to growth of cartilage in the synchondroses

A

True

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67
Q

What features do you expect to see in a skeletal mesiocclusion (Class III)?

A
  • Often prognathic Md, occasionally retrognathic Mx
  • Protruded Lower Incisors, Edge-to-Edge bite, Crossbite
  • Class III Canine Relationship
    Incisors
  • Class III Molar Relationship
  • Crowding/Spacing more likely in uppers
  • Constricted Mx Arch
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68
Q

Which facial profile occurs when the Vertical G’-Sn-Pog’ line slopes anteriorly, with Pog anterior relative to glabella in sagittal plane?

A

Concave Profile (Anterior Divergence)

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69
Q

T/F: A Maxillary expansion device is an example of a orthopaedic device

A

True - It is an orthopaedic device that impacts skeletal growth/shape with dental effects

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70
Q

Forwards Rotators result in what sort of face?

A

Short Face

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71
Q

What are 6 determining factors that shape the molar relationship?

A
  1. Magnitude of step in terminal plane
  2. Type of facial growth pattern e.g. horizontal and vertical
  3. Amount of interdental spacing
  4. Early loss of deciduous teeth
  5. Any loss of arch length
  6. Amount of Leeway space
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72
Q

When should eruption of primary dentition be complete?

A

2.5 - 3 years of age

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73
Q

What is the Bjork Classification?

A

A means of classifying the molar occlusion of 1st permanent molars

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74
Q

What are some psychosocial reasons that a person might consider orthodontics?

A

Variability from norm
Appearance creates isolation, bullying
Increased aesthetic norms

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75
Q

How much earlier do lower permanent canines erupt in females compared with males?

A

12 months

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76
Q

T/F: People of black ethnic origins will experience tooth eruption earlier than others

A

True

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77
Q

What are some examples of craniofacial deformities where orthodontics could be considered?

A

Cleft Lip + Palate
Severe Accidents
Patients with Syndromic Conditions
Severe Class II/III patients considering Orthognathic Surgery

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78
Q

What determines the tooth positions of accessional molars?

A
  1. Vertical alveolar growth
  2. Maxilla: Posterior deposition in tuberosity region
  3. Mandible: Resorption of the anterior border of Mandible - providing additional space in the dental arch
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79
Q

What are issues with Moyer’s Analysis?

A
  1. Premature Tooth Loss: secondary crowding, loss of arch space
  2. Prolonged Tooth Retention: affects emergence time and direction, depends on which tooth and its position in the arch (ie lowers incisors)
  3. Asymmetrical arches: affects midlines
  4. Severity of Crowding/Spacing: access to contact points, harder to assess arch shape, need to account for midline diastema
  5. Facial Pattern: influences arch size and shape, soft tissue pattern affects tooth position, apical base dimensions and position
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80
Q

What hormonal factors can alter dental development?

A
  1. Increased maturity after menarche (first menstruation)

2. Delayed development through hypothyroidism

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81
Q

How long can it take for an erupting tooth to reach the opposing dentition?

A

1-2 years

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82
Q

What is the difference between endomorph, mesomorphy and ectomorph body types?

A
  1. Endomorph: Preponderance of Body Fat
  2. Mesomorph: Predominance of muscle, bone and CT
  3. Ectomorph: Preponderance of skinny and delicate build
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83
Q

What shape face might you expect with an Endomorph?

A

Square face: short and obese body type

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84
Q

What is the main reason for natal teeth?

A

Ectopic position of tooth germ in foetal life allows for early eruption

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85
Q

What is the difference between Baume Type I and II?

A

Baume type I (spaced): generalised spaces between primary teeth

Baume type II (closed): primary teeth are proximal contact

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86
Q

What is secondary crowding?

A

Secondary Crowding is caused by environmental factors influencing the dentition, such as caries, extractions

When teeth extracted, teeth drift forward if no space maintainers placed

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87
Q

What are some systemic factors that can delay tooth eruption?

A 
Down’s syndrome 
Hypothyroidism
Hypopituitarism
Hypovitaminosis (A&D)
Osteopetrosis
Cleidocranial dysplasia
Hereditary Gingival Fibromatosis
Achondroplasia
Amelogenesis Imperfecta
Familial Patterns (Genetic)
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88
Q

What is the Symphyseal cartilage and when does it disappear?

A

Unites 2 halves of mandible at symphysis and ceases after 1st year of birth

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89
Q

What is the main reason for delayed eruption?

A

Insufficient space

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90
Q

What is Inter-Canine Width?

A

Horizontal distance between right and left canine cusp tips

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91
Q

Early intervention of Class II skeletal relationship will require what sort of orthodontic treatment?

A

Functional appliance
Fixed Appliance
Orthognathic surgery

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92
Q

What are the implications for standardising orthodontic treatment based on the combinations of Proffit’s sagittal cranial diagram?

A

Every patient is unique: combinations of all skeletal + dental relationships is 3 power 12 = 531441 combinations

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93
Q

What is Dento-alveolar compensation?

A

Where tooth eruption and alveolar development will compensate for the apical base dimension if there are skeletal discrepancies.

This will result in malocclusion seen in class II/III occlusions

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94
Q

What are the 3 orthodontic considerations for aesthetics?

A
  1. Facial
  2. Dentofacial
  3. Smile: particular impact of extraction/non-extraction in treatment
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95
Q

What are 5 issues with measuring anterior + posterior segments to determine arch length discrepancy?

A
  1. Partially Erupted Teeth give incomplete readings
  2. Impacted Ectopic / Missing Teeth
  3. Parallax error of calipers
  4. Straight Line approach cuts off true arch length
  5. Doesn’t take into account tooth displacement (eg rotation)
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96
Q

When is the most common period for lip incompetence

A

9-13 years and often resolves over puberty

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97
Q

Ossification of the mesenchyme and ectomesenchyme covering the developing brain is dependent upon influences from what tissue type?

A

Neural epithelium

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98
Q

What permanent teeth do we expect to see at age 7?

A

Upper 1s

Lower 2s

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99
Q

What are the 4 stages of Fisher’s Skeletal Maturity Indicators?

A
  1. Width of Epiphysis = Width of Diaphysis
  2. Ossification: Development of Adductor sesamoid of Thumb
  3. Capping of Epiphysis
  4. Fusion of Epiphysis to Diaphysis
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100
Q

What is the main determinant of tooth position of successional permanent teeth?

A

The position and resorption patterns of primary teeth

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101
Q

What are issues with appliances that are left on for too long?

A

Issues with poor OH
Major Tooth Resorption
Loss of periodontal attachment

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102
Q

What are the 5 growth sites in the cranial base?

A 
Foramen magnum (apposition at Ba)
Spheno-occipital synchondrosis (endochondral growth)
Spheno-ethmoidal synchondrosis (endochondral growth)
Fronto-ethmoidal suture
Frontal bone (surface apposition)
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103
Q

What are considered Mini Aesthetics when assessing a patient?

A

Tooth Lip Relationships

  • Midline Relationship
  • Maxillary Cant
  • Incisal Display
Smile Analysis (Static/Dynamic)
Incisal Display
Gingival Display
Buccal Corridors
Smile Arc
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104
Q

T/F: Coronoid cartilage is present at birth

A

False - Coronoid cartilage is a strip along the anterior border of the coronoid notch that disappears before birth

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105
Q

What are the progenitor cells for Meckel’s Cartilage?

A

Ectomesenchymal (neural crest) origin

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106
Q

What is Incisor Liability?

A

Difference between the mesial-distal diensions of the permanent incisors vs the primary incisors

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107
Q

What does Powell’s Naso-Facial Angle (G-Pog to N-NT) tell us?

A

Range: 30-40

Decreased Angle = Skeletal Prognathic Mandible

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108
Q

Which facial profile occurs when the Vertical G’-Sn-Pog’ line is parallel to the true vertical line?

A

Straight Profile (Natural Divergence)

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109
Q

What is most common terminal plane relationship in children?

A

Flush terminal plane.

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110
Q

What is impaction?

A

Failure of a tooth to reach its normal position by bone, tissue or another tooth

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111
Q

What are 3 possible outcomes of arch length discrepancy measurements

A

Spacing
Perfect alignment
Crowding

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112
Q

According to Ackermann-Proffit, how can alignment be described?

A

Ideal
Crowded
Spaced
Mutilated

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113
Q

What is Bolton’s Analysis?

A

Determine the compatibility / discrepancy between size of maxillary and mandibular teeth. This helps determine the ideal interarch relationship

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114
Q

What is the Ackerman-Proffit Classification ?

A

Describing the skeletal relationship between the maxilla and mandible

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115
Q

What are deficiencies in Angle’s Classification?

A

Static Description
Molar relationship could change
No reliable indication of underlying skeletal pattern
No functional indication of how jaw works
No soft tissue description (tongue, lips, gingiva)
No vertical or transverse description

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116
Q

What is Bjork Class I Occlusion?

A

Class I Occlusion - Normal, or at most one-half cusp postnormal or prenormal

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117
Q

What accounts for the lowering growth position in the naso-maxillary complex?

A

Resorption at orbital and nasal floors

Deposition along hard palate

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118
Q

What is the BSI Incisor Class I?

A

Cingulum Plateau of Mx Central Incisors occludes with the opposing Md incisal edge

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119
Q

What is the growth direction the naso-maxillary complex?

A

Displacement downwards and forward

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120
Q

What accounts for the forwards growth position in the naso-maxillary complex?

A

Soft tissue development in the mid-face region

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121
Q

What are signs of poor oral hygiene in a orthodontic patient?

A

Decalcifiction of buccal surfaces

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122
Q

Does mandibular forward/backwards rotation itself cause malocclusion?

A

No - as there is dentoalveolar compensation to a point

Malocclusions such as deep overbite or anterior open bite occur when the dentition is unable to compensation for severe rotation

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123
Q

What are examples of bite depth (vertical relationship) in Ackermann-Proffit?

A 
Anterior Open Bite
Posterior Open Bite
Anterior Deep Bite
Posterior Collapsed Bite
Dental
Skeletal
Combined Skeletal and Dental
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124
Q

T/F: Functional appliance are responsible for growing the jaw.

A

False - as it doesn’t work on an adult. It creates an optimal environment for growth during the peak growth phase

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125
Q

How do permanent incisors fit during eruption?

A
  1. Residual spacing between deciduous incisors
  2. Labial Eruption Path: permanent incisors erupt into more labial position (esp. in Mx) and occupy a greater arch perimeter
  3. Deciduous canines move distally into primate spaces as incisors erupt
  4. Transverse increase in intercanine arch width
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126
Q

What is contained within the apical base?

A
  1. Crowns of the Teeth (Both erupting + developing)

2. Roots of the Teeth

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127
Q

T/F: Proportionally the combined growth of upper + lower lips exceeds LAFH

A

True

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128
Q

What is supraocclusion?

A

When a tooth has erupted past occlusal level (overeruption)

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129
Q

Why is incisor relationship important?

A

Clinically relevant as it is a truer reflection of skeletal base relatinoship

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130
Q

What is the shedding order of primary teeth?

A

Same as eruption: ABDCE

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131
Q

Which part of the nose grows in size?

A

The septal cartilage

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132
Q

What is Interceptive Orthopaedics and when can it be conducted?

A

Any procedure that reduces the severity of malocclusion in the adult dentition (ceasing of parafunction, extractions, movement of teeth) - up to 11.

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133
Q

What are limitations of Angle’s classification?

A
  1. Can’t use if there are absent FPMs
  2. Does not differentiate molar relationships between both sides of mouth
  3. Does not specify the magnitude of discrepancy (especially crowding/OB/OJ)
  4. Does not specify skeletal or facial patterns
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134
Q

What are the 5 components of Proffit’s sagittal cranial diagram?

A

Cranial Base > Maxilla > Maxillary Dental Base > Mandibular Dental Base > Mandible

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135
Q

Describe what happens to forward rotators?

A

Mandibular Rotation axis is upwards and forwards around the most distal occluding molar, shortening the face

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136
Q

What are risks of orthodontic treatment?

A
  1. Small Loss of periodontal attachment
  2. Root resorption: may be significant in susceptible people
  3. Poor OH
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137
Q

Where is the Nasal Dorsum (Nd)?

A

Soft tissue landmark - the visible hump along the bridge

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138
Q

What diagnostic records are helpful in orthodontic diagnosis?

A
  1. Intraoral Radiographs (OPG, B/W, PA, Lat Ceph)
  2. Study Model Casts (Occlusion, Space Analysis)
  3. Extra Oral Photos (Frontal/Profile/Smile/Lips)
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139
Q

Is complete symmetry an aesthetic quality?

A

No: full symmetry appears weird to the human eye, but beauty is often judged by the lack of gross asymmetry

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140
Q

What trends occur in Inter-Canine Width between 12-18 years?

A

Md: Decrease 1-2mm after eruption of 3s until age 45 → late lower incisor crowding
Mx: Increase 1-2mm after eruption of 2s until age 45

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141
Q

What is Crouzon Syndrome?

A

Sporadic / Autosomal Dominant gene disorder: Craniosynostosis: Characterised by premature fusion of multiple sutures from an early age

Leads to:

Craniosynostosis
Brachycephaly (wide face)
Ocular proptosis (bulging eyes)
Midfacial malformation (Mx hypoplasia => dental crowding)
Class III occlusion
Conductive hearing loss
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142
Q

What are the different types of backwards rotators?

A

Type I: Point of rotation about the condyle, resulting in an increased anterior face height
Type II: Point of rotation around the most distal occluding molar

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143
Q

What is the cephalocaudal gradient?

A

Growth potential is greater in structures more distant from brain, but structures close to brain complete development sooner than those more distant

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144
Q

What is considered aesthetic in regards to buccal contours (negative space)?

A

Minimal empty space to give smile a broad appearance (think Julia Roberts)

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145
Q

What is the main treatment for Open Bite?

A

Identifying aetiology and ceasing the parafunctional habit that caused it

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146
Q

What is a Euryprosopic facial type?

A

Broad face type when referring to extra-oral features

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147
Q

Describe what happens to backwards rotators?

A

Mandibular Rotation axis is on condyle going posteriorly, leading to lower face becoming longer

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148
Q

What features do you expect to see in a skeletal distoclusion (Class II Div 1)?

A
  • Often retrognathic Md, occasionally prognathic Mx
  • Proclined Incisors
  • Full Unit Class II Canine Relationship
  • Full Unit Class II Molar Relationship
  • Overbite: Open to Deep, Possibly Traumatic
  • Arch Shape: V shaped
  • Variable crowding/spacing
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149
Q

What occlusion type are overbites most commonly found?

A

Class II Div II

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150
Q

What are factors that influence growth and development?

A 
Genetics 
Neural control
Hormones
Nutrition
Disease
Socio-economic status
Season/climate
Exercise 
Secular trends
Emotion
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151
Q

Where is the Labiale Superior (Ls)?

A

Soft tissue landmark - Point denoting vermilion border of upper lip

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152
Q

Where is the Labiale Inferior (Li)?

A

Soft tissue landmark - Point denoting vermilion border of lower lip

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153
Q

What is rotation?

A

When a tooth has been rotated around it’s long axis. Often congenital.

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154
Q

T/F: Excessive overjet increases the risk of dental trauma

A

True, makes fracture/avulsion of teeth from physical force injuries / falls more probable

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155
Q

What time of day correlates with eruption?

A

8pm- Midnight: governed by circadian rhythm and growth hormones

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156
Q

Where can primate spaces generally be found?

A

Md is usually mesial to the C

Mx usually distal to the C

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157
Q

How many bones are there in the carpels?

A

8

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158
Q

When will malocclusions occur?

A

Where there is a lack of dento-alveolar compensation from a lack of facial and alveolar growth to accommodate permanent dentition

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159
Q

What is Rickett’s Esthetic Plane (E-Plane)?

A

Soft tissue assessment that gauges lip position from a line drawn from pronasale and soft tissue pogonion (ST Pog) (tip of nose to chin)

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160
Q

What is Orthodontic Camouflage and when can it be conducted?

A

After peak growth (11+), only changes to teeth to mask an underlying skeletal discrepancy

161
Q

What directions does the chin grow?

A
  1. Anterior aspect of mandibular alveolus at symphysis is resorptive
  2. Bottom Chin at mandibular border is additive
162
Q

The cranial vault is comprised of which bones?

A

Frontal
Temporal
Occipital
Parietal

163
Q

What are issues with the Greulich and Pyle Atlas as a predictor of skeletal age?

A

Index is decades old
No consideration of genetic/ethnic differences
No consideration of environmental factors that can stunt/accelerate growth (starvation, nutrition)

164
Q

What factors can affect growth rate?

A 
Normal variation
Hereditary factors
Birth weight
Nutrition
Behavioural/social development
165
Q

Which grows faster - maxilla or mandible?

166
Q

What chin types are consider most unaesthetic?

A

Severe class II or III

167
Q

What does Powell’s Naso-Mental Angle (N-NT to NT-Pog) tell us?

A

Range: 120-132

Decreased Angle = Skeletal Retrognathic Mandible

168
Q

According to the Cephalocaudal Gradient, which structure is the most developed at birth?

A

Head and Neck

169
Q

Heavy abrasion/attrition from Indigenous diets resulted in what changes to malocclusion ?

A

Interproximal attrition > Mesial Movement + Early eruption of 3rd molars > Elimination of milder malocclusion.

Tendency to:

  • Mesial movement into Class III Occlusion
  • Edge to edge bite
  • Flattened curve of spee
  • Reduced dental arch length
170
Q

What does Powell’s Facial Profile tell us?

A

Broad line to work out of facial profile is straight, convex or concave

171
Q

Should avulsed primary teeth be implanted again?

A

No - as risk of ankylosis means that this could prevent permanent teeth from erupting

172
Q

Where is the Menton (Me)?

A

Soft tissue landmark - Lowest point on mandibular symphysis

173
Q

What are several methods to estimate arch length discrepancy?

A
  1. Measuring Anterior + Posterior Segments
  2. Arch form analysis (using Nitinol arch wire)

Both methods measure individual M-D tooth width then compare cumulative tooth widths to arch length

174
Q

What permanent teeth do we expect to see at age 18-24?

A

Upper and Lower 8s

175
Q

What relationship should there be for good aesthetics in contacts?

A

Teeth should be in contact

176
Q

What features do you expect to see in a skeletal distoclusion (Class II Div 2)?

A
  • Often retrognathic Md, occasionally prognathic Mx
  • Retroclined Incisors
  • Full Unit Class II Canine Relationship
  • Full Unit Class II Molar Relationship
  • Overbite: Open to Deep, Possibly Traumatic
  • Arch Shape: Broad and flattened anteriorly
  • Variable crowding/spacing
177
Q

What shape face might you expect with an Ectomorph?

A

Long and Lean face: tall and long body type

178
Q

What are limitations to eruption counts in calculating dental age?

A
  1. Unerupted Teeth (Agenesis/Impaction)
  2. Tables only go up to 16 years
  3. Accelerating/Delaying Factors (Ectopic Position, Insufficient space, retained primary roots)
179
Q

T/F: Malocclusions can alter the perception of individuals with their peers and teachers

A

True, but characteristics that have positive/negative weightings are highly variable depending on age, gender, culture, relationship type (peer, authority, teacher)

180
Q

What cellular growth occurs during post-natal growth?

A

Cell and matrix increase

181
Q

What defines a scissor bite?

A

when one or more adjacent posterior teeth are completely buccal/lingually to the opposite teeth and display a full vertical overlap

182
Q

What cranial shape is Brachycephalic ?

A

Short-wide head: horizontally shorter and transversely wider

183
Q

Where is the A Point?

A

Soft tissue landmark - the most concave point of the anterior maxilla

184
Q

T/F: Growth of the maxilla is a combination of soft tissue matrix and cartilage

185
Q

What are features of forwards rotators?

A

Flattens occlusal plane
Increased Overbite
Lower Incisor Crowding with age
Slow space closure

186
Q

T/F: Facial growth can continue slowly for decades?

A

True. Growth can happen in:

Tooth eruption
Nose growth
Ear enlargement
Condyles and chin

187
Q

How does Nolla Calcification Staging work in calculating dental age?

A

Measure the development of a tooth radiographically against 10 stages to gauge maturity. The tooth is then plotted against statistical averages for Mx/Mn arches to determine the dental age.

Overcomes issues with crowding/delayed eruption.

More indicative of true growth and development

188
Q

How are Growth and Development different?

A

Growth: An increase in tissue size
Development: An increase in tissue organisation and specialisation

189
Q

Why do individuals decrease in height in old age?

A

Joint Compression and Vertebral degeneration

190
Q

What are methods measuring bone ossification?

A

Hand Radiographs that are referenced between different growth scales:

1) Greulich and Pyle Atlas - measuring development of carpal bones, distance between bones and development of hamate
2) Fisher’s Skeletal Maturity Indicators - Evaluating development and fusion of epiphysis in fingers

191
Q

What permanent teeth do we expect to see at age 9?

192
Q

Which is more common, backwards or forwards rotators?

A

Forwards = 80% of population

193
Q

What is the difference between Tipping and Displacement?

A

Tipped: apex normally placed but crown incorrectly positioned

Displaced: apex and crown incorrectly positioned

194
Q

What are the aesthetic qualities when displaying a lip line when smiling?

A

On smile: full crowns of maxillary Incisors + 1-2mm of gingiva visible during smiling

195
Q

What is the zone of equilibrium?

A

The tooth position post eruption that is influenced by soft tissues and oro-facial function. This is the same as the neutral zone in occlusion

196
Q

Which part of the face keeps grows the most rapidly?

197
Q

Which part of the nose is responsible for change of shape during growth?

A

Proliferation of lateral cartilage

198
Q

What is Bjork Class Prenormal Occlusion?

A

Class III Occlusion - where the mandibular 1st molar is more than one-half cusp anterior of pre-normal relation

199
Q

What molar relationship is likely to occur for a Class II Flush Terminal Plane?

A

Likely Class II Molar

200
Q

What permanent teeth do we expect to see at age 10?

A

Lower 3s, Lower 4s

201
Q

When should orthodontic treatment be started?

A
  1. When all permanent dentition has erupted (most cases)

2. Early Teens

202
Q

What is possible to manipulate during active facial growth?

A
  • Tooth Eruption

- Change direction to better utilise growth

203
Q

What is the apical base?

A

The portion of the jawbone that give support to the teeth

204
Q

What permanent teeth do we expect to see at age 6?

A

Upper and Lower 6s

Lower 1s

205
Q

Should natal teeth be extracted?

A

No - could damage other tooth germs

206
Q

Which facial profile has posterior divergence?

A

Convex Profile

207
Q

Which facial profile has anterior divergence?

A

Concave Profile

208
Q

What cranial shape is Mesocephalic?

A

Average head in proportion

209
Q

What accounts for the increase in width of the naso-maxillary complex?

A

Growth at mid-palatal suture

210
Q

What molar relationship is likely to occur for a Class I Flush Terminal Plane?

A

Likely Class I Molar

211
Q

What is the terminal plane relationship?

A

The terminal plane relationship of primary second molars determines the amount of leeway space that is available for permanent premolars and canines. I can be used to predict the occlusion relationship in the permanent dentition.

212
Q

What indications are there to start orthodontic treatment when there is late mixed dentition?

A 
Ectopic 3s
Poor quality 1st Molars (FPM)
Infraocclusion
Hypodontia
Traumatic overbite
Increased overjet
213
Q

What does Powell’s Mento-Cervical Angle (G-Pog to C-Me) tell us?

A

Range: 80-95

Decreased Angle: Longer Facial Height, Backwards Rotator

214
Q

What is the eruption sequencing of primary dentition?

215
Q

What are limitations to Nolla Calcification Staging in calculating dental age?

A
  • Requires OPG to make assessment

- Somewhat subjective measure

216
Q

What contributes to a small level of height growth in individuals from 20-30?

A

Deposition of bone on the vertebrae

217
Q

Why is skeletal bone ossification a good marker for orthodontic planning?

A

Determines onset of growth spurt that corresponds with orthopaedic changes - this can reduce treatment time. However this needs to be considered with the level of dental maturity as well

218
Q

Where is the Columella (Cm)?

A

Soft tissue landmark - the tissue that links the nasal tip and nasal base - on the inferior margin of the nasal septum

219
Q

Where is the B Point?

A

Soft tissue landmark - the most concave point of the mandibular symphysis

220
Q

What are the clinical implications of residual meckle’s cartilage?

A

Transmigration of mandibular canines

221
Q

If a tooth’s gingival margin is considerably lower than the rest of the arch, is it infraocclusion or infraposition?

A

Infraposition: failure of the alveolar bone to keep growing due to trauma from ankylosed tooth.

The gingival margin on a infraocclusion tooth will be in line with the rest of the arch

222
Q

What sort of chin is considered most attractive

A

Ideal sagittal position of ST Pog is on or just behind true vertical line through subnasale.

223
Q

What are cranial vault sutures comprised of?

A

Connective Tissue that allow for intramembranous ossification that is reactive to tension provided at the margins

224
Q

What are landmarks for Cranial Base Superimposition?

A
  1. Sella Turcica (anterior wall of pituitary fossa
  2. Lamina Cribrosa (Contour of cribriform plate of ethmoid)
  3. Trabecular outline of Ethmoid Air Cells
  4. Medial Border of Orbital Roof
  5. Plane of Sphenoid
  6. Greater wings of sphenoid
225
Q

What is tertiary crowding?

A

Tertiary Crowding occurs occurs in post-adolescent period and is a normal part of the aging process. This will occur naturally without the use of fixed/removal retainers

226
Q

What are buccal contours (negative space)?

A

Space between the buccal surface of the posterior teeth and commissures during smiling

227
Q

T/F: Class I/II/III in the Foster Classification correspond with the Bjork Classification

A

False, as Foster describes primary molars, Bjork describes FPM

228
Q

What cranial shape is Dolichocephalic?

A

Long Head: horizontally long and transversely narrow (<75% H:W ratio)

229
Q

What are the limitations of Bolton’s Analysis?

A
  1. Bolton’s sample size for relationships was white caucasian only
  2. Sample group only had perfect malocclusions

Therefore its likely that most people will fall outside of normal

230
Q

What has happened to the condylar cartilage by 5 months in utero?

A

Most of the condylar cartilage has ossified except narrow cap beneath articular surface of condyle

231
Q

Is Anterior Open Bite likely to resolve without treatment

A

No, if related to skeletal problems and not parafunction

232
Q

What are 4 different types of direct measurements for growth?

A
  1. Anatomical Measure
  2. Secondary Sexual Characteristics
  3. Lateral Cephalometry
  4. 3D finite element model
  5. MRI
  6. CT Scanning
233
Q

Which grows faster - facial region or vault of skull

A

Facial Region

234
Q

What 2 mechanisms allow for post natal growth of the mandible?

A
  1. Bony remodelling via subperiosteal resorption and deposition
  2. Cartilaginous growth at condyle
235
Q

What are features of backwards rotators?

A

Increased Anterior Face Height
Long Face
Class II Skeletal Relationship
Reduced Overbite

236
Q

What does Powell’s Naso-Frontal Angle (G-N-NT) tell us?

A

Range 115-130

Decreased angle = Skeletal Prognathic Maxilla

237
Q

What are issues with natal teeth?

A

Likely to be mobile due to limited root development

238
Q

What is a pseudo Class III?

A

When there is a premature contact in central relation, the patient must protrude mandible forward to clear contact. This gives the illusion of Class III

Resolution - remove premature contact

239
Q

What would be the cause of a Straight smile arc?

A
  • Incorrect Orthodontic positioning of incisal edges

- Age related tooth wear

240
Q

Where is the Pronasale (Pn)?

A

Soft tissue landmark - the point of the angle between the septum of the nose and the surface of the upper lip, found at the point where a tangent applied to the nasal septum meets the upper lip.

241
Q

What 6 factors hamper ideal dental alignment?

A
  1. Lack of interdental, primate and leeway spaces
  2. Reduction in dental arch length after permanent incisors erupt
  3. Dento-alveolar disproportion
  4. Early loss of primary teeth
  5. Soft tissue
  6. Oral habits
242
Q

What is Bimaxillary Protrusion?

A

When both jaws are protrusive → protrusion of Mx and Md in relationship to the Anterior Cranial Base

243
Q

What are the 9 Ackermann-Proffit groups?

A

Group 1: Alignment Problems
Group 2: Alignment, Profile Problems
Group 3: Alignment, Profile, Transverse Problems
Group 4: Alignment, Profile, Sagittal Problems
Group 5: Alignment, Profile, Vertical Problems
Group 6: Alignment, Profile, Transverse and Sagittal Problems
Group 7: Alignment, Profile, Sagittal and Vertical Problems
Group 8: Alignment, Profile, Transverse and Vertical Problems
Group 9: Alignment, Profile, Transverse, Sagittal and Vertical Problems

244
Q

What is Angle’s line of occlusion?

A

Shows how teeth should normally occlude: Incisal edges and buccal cusps of the Md arch coincide with the cingulum of the incisors and canines plus the premolar and molar fossae in the Mx arch

245
Q

What are the most common natal teeth?

246
Q

What are problems with ectopic teeth?

A

Can caused root resorption of impacted teeth if not treated

247
Q

What are the pre-emergent tooth positions of successional canines?

A
  1. Maxillary canines start below the floor of the orbit (hence eye teeth)
  2. Located between the roots of the 1st primary molar (D)
  3. Erupt distal and lingual to primary canines
248
Q

According to Proffit, what are the 3 main orthodontic issues?

A
  1. Crowing/Protrusion = psychosocial handicap
  2. Malocclusion = functional handicap (AOB/Supereruption)
  3. Malocclusion = increased risk of pathology (crowding => caries/perio)
249
Q

What is the BSI Incisor Class II Div I?

A

Lower incisor edges lie posterior to the cingulum plateau of the upper incisors and the incisors are proclined

250
Q

What is Foster and Hamilton Class II Occlusion?

A

Distal surface of lower 2nd molar in posterior relationship to that of upper 2nd in centric occlusion

251
Q

What relationship should there be for good aesthetics in gingival contours?

A

Central incisors and canines: Gingival margins should be level

Lateral Incisors: should like 1mm more incisally

252
Q

What is Orthognathic Surgery and when can it be conducted?

A

Surgery changes to the craniofacial skeleton conducted after peak growth (13+) so that changes won’t be undermined by continued facial and skeletal growth

253
Q

What are natal teeth?

A

Natal teeth are teeth that are present above the gumline (have already erupted) at birth

254
Q

What are the pre-emergent tooth positions of successional incisors?

A

Permanent teeth lingual to primary teeth

255
Q

What drives the growth of the surface area of the cranial value?

A

Displacement of bone by growth of the brain and osteogenesis at the sutural margins

256
Q

What can be seen by Cephalometric Superimposition?

A
  1. Completion of Cranial Base Growth
  2. Maxillary growth/rotation from development + orthodontic treatment
  3. Maxillary growth/rotation from development + orthodontic treatment
257
Q

T/F: Growth of the cranial vault occurs largely by growth at the sutures and surface remodelling and is primarily due to growth of the brain

258
Q

Where is the Gnathion (Gn)?

A

Soft tissue landmark - Point located perpendicular on mandibular symphysis midway between pogonion and menton

259
Q

T/F: Molar Angle’s Classification is congruent with skeletal relationship

260
Q

T/F: The nose continues to grow after skeletal growth finishes

261
Q

What relationship should there be for good aesthetics in connectors?

A

Connectors decrease as you move posterior

262
Q

The Cranial Base comprise of which bones?

A

Frontal
Ethmoid
Sphenoid
Occipital

263
Q

What are considered Micro Aesthetics when assessing a patient?

A

The appearance of dentition:

Tooth Proportions
Width Relationships (Golden proportions: 62% each size tooth distally)
Height / Width Relationship (80%)
Gingival Height, Shape and Contour
Connectors (interdental contact area): becomes smaller moving distally
Embrasures
Tooth Shade and Colour

264
Q

What is crowding?

A

Discrepancy between tooth size and jaw size (apical base) that results in the misalignment of teeth

265
Q

What developmental feature in the hamate bone is part of the Greulich and Pyle atlas?

A

Hamate develops an exostosis perpendicular to the open palm during puberty and is clinically visible as a radiopaque density on a hand radiograph

266
Q

What accounts for the increase in height of the naso-maxillary complex?

A

Sutural growth at zygomatic and frontal articulations

Deposition at alveolar processes

267
Q

When does the Ugly Duckling phase resolve

A

Once the full compliment of Maxillary anteriors has erupted.

268
Q

How can overbite be described

A 
Open (Anterior Open Bite)
Reduced
Average
Increased (complete)
Increased (traumatic - against palate)
Increased and incomplete (likely severe Class II Div 1)
269
Q

What is tooth eruption?

A

Process whereby a tooth moves from its developmental position in the jaw into its functional position in the mouth

270
Q

What is the calcification order of primary teeth?

271
Q

T/F: Proportionally Lower Lip Growth exceeds Upper Lip Growth

272
Q

What are the 3 types of smile arcs?

A

Consonant
Straight
Non-Consonant

273
Q

What are the 2 means of craniofacial growth?

A
  1. Sutures

2. Surface Remodelling

274
Q

T/F: Growth of the mandible is due to soft tissue matrix

275
Q

What is leeway space?

A

The Difference between C - E and the 3-5

276
Q

What is Dentofacial Orthopaedics and when can it be conducted?

A

Guidance of facial growth and development to achieve skeletal changes (eg functional appliances and headgear). Needs to occur before peak growth (up to 13)

277
Q

The face is comprised of what 2 elements?

A

Naso-maxillary Complex

Mandible

278
Q

What indications are there to start orthodontic treatment when there is early mixed dentition?

A 
Non nutritional sucking behaviour
Delayed Eruption
Financial Reasons
Early Loss of Primary Teeth 
First permanent molar impaction
Crossbites
Severe Crowding
Increased Overjet
279
Q

What is transposition?

A

2 teeth that have switched position

280
Q

What are indirect anatomical measures that could be used for measuring growth and development?

A
  1. Indirect measurements: Biologically Active Agents (Tetracyclines, Alizarin, Procion Dyes)
  2. Histology (LEM, Radioisotope Labels, Histochemical markers)
281
Q

What is the Suture theory of craniofacial growth and why is it not current dogma?

A

Bones are pushed apart as a result of pressure created by active growth at the sutures growth centres.

Debunked: Transplanted sutures fail to grow. Growth inhibited when sutures are compressed

282
Q

How does Hereditary gingival fibromatosis affect tooth eruption?

A

Thick gingiva slows eruption times

283
Q

When would you ignore the golden proportion in the aesthetic anterior zone?

A

If there is insufficient space in the arch.

284
Q

Which malocclusion is more likely to have lip incompetence?

A

Class II Div I

285
Q

In terms of cervical vertebrae maturation staging, which stage is indicative of the optimal phase to start orthodontics

A

CS3: concavities on the lower borders of C2 / C3

286
Q

What are the implications of Bolton’s Discrepancy?

A
  1. Aesthetic disproportions of upper vs lower dentition

2. Impact of Occlusion relationship, interdigitation and function

287
Q

What should you expect to see clinically for permanent canines at age 11?

A

Eruption into the oral cavity

288
Q

When describing a crossbite, which tooth do we reference as being out of alignment?

A

The Maxillary Tooth involved in the crossbite

289
Q

What is Foster and Hamilton Criteria?

A

A means of classifying the molar occlusion of primary second molars in centric occlusion

290
Q

What is a main reason for prevention of eruption of a permanent tooth?

A

Failure of superior primary tooth to undergo root resorption.

291
Q

What is the Golden Relation and where can it be used?

A

Ideal Proportions (1:1.618) that are judged by human eye as comforting/pleasing

  • Crown width/height
  • Soft Tissue Relationships
  • Hard Tissue Relationships (OMFS/Plastic Surgery)
292
Q

What changes to the nose occur during peak growth period?

A
  1. N angulation can change by 30%
  2. Dorsum can lengthen by 1 mm/year
  3. Columella depth may change by 0.5mm/year
293
Q

How can the presence of bimaxillary protrusion be measured?

A

When SNA > 81, SNB > 78 but ANB is still within 3±2

294
Q

What is the role of the general dentist in orthodontic treatment?

A 
Detect Anomalies Early
Oral Hygiene Monitoring
Orthodontic Extractions
Restorative Treatment
Route Dental Checkups
295
Q

What is Ackerman-Proffit Skeletal Class I?

A

Mx 2-4mm anterior to Md

296
Q

Backwards Rotators result in what sort of face?

297
Q

What are the different incisal relationships in Angle’s Classification?

A

Class I (Mn into Mx cingulum plateau)
Class II Div 1 (Mx incisor proclined, occlusion more posterior)
Class II Div 2 (in cingulum plateau, Mn incisor retroclined)
Class III (Mn incisor in Mn cingulum plateau)

298
Q

T/F: Lip Line decreases with age

A

True - you would then expect to see less gingiva exposed in the lip line on older people

299
Q

T/F: High irregularity does not necessarily mean crowding

A

True

Tipping irregularity can be related to soft tissue, NNSH

Often crowding related to skeletal deficiency to dentition

300
Q

How does eruption count work in calculating dental age?

A

Compare number of emerged permanent teeth against gender + Mn/Mx defined statistical averages to gauge dental age

301
Q

What broad categories are there for nasal types?

A

In the nasal index:

1) Narrow (European): Type 1-5
2) Medium (Oriental): Type 6
3) Broad (African/Islander): Type 7-8

302
Q

What are the 2 key structures in the mandible develop from the 1st Pharyngeal Branchial Arch?

A

Meckel’s Cartilage

Inferior Alveolar Nerve

303
Q

What are possible effects of crossbites?

A

Proclined incisors, dehiscence, loss of bone of labial aspect of root, can lead to loss of tooth

304
Q

What is the BSI Incisor Class III?

A

Lower incisor edges lie anterior to the cingulum plateau of the upper incisors

305
Q

What are direct anatomical measures that could be used for measuring growth and development?

A
  1. Height Z-Scores and Percentiles
  2. Weight for Age
  3. Body Component Size/Ratios (Head/Arm circumference for age)
306
Q

Where is the Subnasale (Sn)?

A

Soft tissue landmark - the point where the nasal septum merges with the upper lip

307
Q

What is a Leptoprosopic facial type?

A

Tall, Narrow face type when referring to extra-oral features

308
Q

What are the 4 phases of growth in life?

A
  1. Embryo (essentially increase in size)
  2. Foetus → adult (specialisation)
  3. Adult (maintenance)
  4. Old age (deterioration)
309
Q

T/F: Chin retrusion or protrusion up to 4 mm is essentially unnoticeable in terms of aesthetics

310
Q

T/F: 3rd Molars contribute towards tertiary crowding

A

False: no evidence as same rates of late crowding occurs in individuals with missing 8s

311
Q

What is the eruption sequence of permanent dentition

A

Maxillary: 6, 1, 2, 4, 3, 5, 7, 8
Mandibular: 6, 1, 2, 3, 4, 5, 7, 8

312
Q

According to the Cephalocaudal Gradient, which structure has the most development potential at maturity?

313
Q

What are considerations for a growing facial profile?

A
  1. A well balanced profile before puberty may deteriorate
  2. Nose + Chin Lengthen
  3. Lips become more retrusive + less full with time
  4. Anticipate nose, chin and lip growth as part of orthodontic planning/treatment
314
Q

What defines a crossbite?

A

A malocclusion where one or more teeth is more buccally/lingually placed to its antagonist tooth

315
Q

What molar relationship is likely to occur for a distal step?

A

100 % Class II Molar

316
Q

What can create Bolton’s Discrepancy?

A
  1. Developmentally Bigger Teeth: macrodontia, fusion
  2. Developmentally Smaller Teeth: microdontia
  3. Agenesis/Extracted Teeth
    Supernumeraries/morphological disharmony (eg peg lateral)
317
Q

What non epiphysis indicators are present in the 11 stages of Fisher’s Skeletal Maturity Indicators?

A
  1. Ossification of the Adductor Sesamoid in the thumb (Stage 4)
  2. Fusion of the Radius (Stage 11)
318
Q

What are the 4 cranial base synchondroses?

A
  1. Fronto-ethmoidal
  2. Spheno-ethmoidal (ossified by 7 years of age)
  3. Inter-sphenoidal
  4. Spheno-occipital (closed by 13-15 years in females, 15-17 in males)
319
Q

What contributes most to vertical face height increase?

A

Tooth eruption and alveolar bone production

320
Q

What is the technique for Maxillary Superimposition?

A
  1. Align the maxillary outlines along the oblique line drawn tangent to the anterior contour of the zygomatic process
  2. Move the overlapping line so that the bony apposition on the orbital floor is equal to the resorption in the nasal floor
321
Q

T/F: Intramembranous ossification in load bearing areas?

A

False

Intramembranous ossification occurs in non-load bearing areas such as the cranial vault, maxilla and mandible

By comparison - endochondral ossification occurs in load bearing areas with cartilaginous pre-cursors: Long bones, Cranial base, Mandibular condyle

322
Q

What are the 2 steps of eruptive movement?

A

1: Resorption of bone and/or primary tooth roots overlying crown of erupting tooth
2: Eruption of tooth through “resorbed” path

323
Q

What 3 factors can result in growth?

A 
Cellular Hypertrophy (size)
Cellular Hyperplasia (number)
An increase in extracellular volume
324
Q

What environmental factors can change the nasal septum?

A

1) Rhinoplasty
2) Saddle Nose: cocaine use/trauma cutting blood supply from nasal septum - destroying tissue
3) Deviated Nasal Septum: physical trauma, breathing tubes during surgery

325
Q

What permanent teeth do we expect to see at age 12?

A

Upper and Lower 7s

326
Q

What are some local factors that can delay tooth eruption?

A
  1. Absence of Teeth
  2. Crowding
  3. Delayed exfoliation of primary predecessors
  4. Impaction
  5. Ankylosis (from trauma to primary teeth)
  6. Arrested tooth formation (trauma)
  7. Cysts, tumours
  8. Sclerotic bone
  9. Abnormal position of Dental Crypts
  10. Failure of eruption of primary teeth or permanent teeth
  11. Dilacerations (roots physically stop tooth from erupting)
327
Q

What are the overlapping categories in Ackermann-Proffit?

A

Tran-Sagittal
Sagitto-Vertical
Vertico-Transverse
Trans-Sagitto-Vertical

328
Q

The cranium is comprised of what 2 elements?

A

Calvarium (Cranial Vault)

Cranial base

329
Q

What is a Angle’s Class I Div II Classification?

A

Retrusion of lower jaw, with distal occlusion of the lower molar distal to upper molar where the central incisors are retroclined

330
Q

What is Arch Circumference?

A

Distance measured round the arch from the mesial contact of 1 FPM to the mesial contact of the other FPM

331
Q

What are the 3 arch change directions that occur between 6-12 years of age?

A
  1. Vertical: increasing facial height
  2. Anterior-Posterior (Mesial/Distal): creating room for permanent molars
  3. Transverse (1-1.5mm after 8 years)
332
Q

What shape face might you expect with an Mesomorph?

A

Proportioned face: robust, athletic with broad shoulders

333
Q

What are considered Macro Aesthetics when assessing a patient?

A 
Development Age
Front Analysis (Symmetry, Horizontal 3rd, Transverse 5ths
Profile Analysis (Convex, Straight, Concave)
Facial Type (Brachy, Dolicho, Meso)
Facial Features (Chin Prominence, Length of Face, Competence of lips)
334
Q

What should be clinically observable dentally at 2.5-3 years of age?

A
  1. Eruption of primary dentition complete
  2. Modest increases in arch width and circumference
  3. Vertical eruption continues + development of alveolar bone
  4. Subtle malocclusions detectable (Class II parafunction, tooth chipping from trauma, non-evulsed teeth, deep overbites)
335
Q

What is the post-emergent spurt?

A

The rapid eruption of a tooth as it enters the oral cavity

336
Q

What’s the implication of the Gnomic Growth pattern on orthodontic treatment?

A

Growth Directions is dependent on underlying skeletal morphology - so without treatment the underlying skeletal pattern is not expected to change on average even with growth

337
Q

What trends occur in arch circumference between 12-18 years?

A

Mx: remains about the same, small increase in males
Md: Decrease significantly between 5-18 years

338
Q

When does a tooth first start to erupt?

A

Once the root begins to form?

339
Q

According to Scammon’s Growth Curve, which system grows the fastest from birth, plateauing around 10 years?

340
Q

What are the 2 main indications for orthodontics?

A

Aesthetics

Function

341
Q

What is the BSI Incisor Class II Div II?

A

Lower incisor edges lie posterior to the cingulum plateau of the upper incisors and the incisors are retroclined

342
Q

What is aesthetics?

A

A set of principles concerned with the nature and appreciation of beauty

343
Q

T/F: Deep bites will resolve somewhat after the eruption of the second molars

A

True: Second molars increases the bite

344
Q

What cellular growth occurs during pre-natal growth?

A

Cell division and specialisation

345
Q

What direction does the mandible grow?

A

Mandible grows upwards and backwards to maintain contact with cranial vault (at TMJ)

Upwards: Condylar growth via endochondral ossification

Backwards: Intramembranous ossification on posterior border of the ramus

Remodelling that helps maintain shape/proportions of bone as it increases

346
Q

What permanent teeth do we expect to see at age 8?

347
Q

What is a Angle’s Class III Classification?

A

Protrusion of lower jaw with mesial occlusion of the lower teeth, with lower incisors and cuspids inclined lingually

348
Q

What is a normal angle classification?

A

MB cusp of upper first molar is received in lower first molar buccal groove

349
Q

How many phalanges bones are present on one hand?

A

14: 5 Distal, 4 Intermediate, 5 Proximal

350
Q

How does Cleidocranial Dysplasia affect tooth eruption?

A

Teeth develop but don’t erupt

351
Q

What are aspects of aesthetics in the transverse plane?

A
  • Evenness in transverse fifths
352
Q

What is Inter-Molar Width?

A

Horizontal distance between right and left central fossae of upper and lower FPMs

353
Q

What is a Angle’s Class II Div I Classification?

A

Retrusion of lower jaw, with distal occlusion of the lower molar distal to upper molar where the central incisors are proclined

354
Q

What is Powell’s Soft Tissue Profile Analysis and what can it measure?

A

Assesses soft tissue profile balance and harmony

Facial Profile (G-Pog and FH)
Naso-Frontal Angle (G-N-NT)
Naso-Facial Angle (G-Pog to N-NT)
Naso-Mental Angle (N-NT to NT-Pog)
Mento-Cervical Angle (G-Pog to C-Me)
355
Q

What would you find in a 1/2 unit class II occlusion

A

Retrusion of lower jaw where the mandible has moved back half a pre-molar width.

Canines would typically be cusp tip-to-tip

356
Q

What is Moyers Mixed Dentition Analysis (Michigan Analysis) used for?

A

Determine whether there is sufficient space for the unerupted buccal teeth (3,4,5) to fit in the space created from exfoliated C, D + E

357
Q

What is Ackerman-Proffit Skeletal Class II?

A

Md retrusive relative to Mx

358
Q

What are examples of types (transverse relationship) in Ackermann-Proffit?

A 
Buccal Crossbite
Palatal Crossbite
Dental
Skeletal
Combined Dental and Skeletal
359
Q

Why are early teens preferred as a window to start orthodontic treatment?

A
  1. Easier to move teeth when mandible growing
  2. Response to orthodontic forces is more rapid compared to adults
  3. Appliances are better tolerated
  4. Growth can be utilised to help sagittal or vertical change
360
Q

What are issues with natal teeth?

A
  1. May make breast feeding uncomfortable/painful

2. Teeth are often sharp and can traumatise lip/tongue/soft tissue

361
Q

What indications are there to start orthodontic treatment when there is established permanent dentition?

A

Most Malocclusion

362
Q

What is the technique for Mandibular Superimposition?

A

Growth can be determined from the angle between the SN lines (anterior cranial base planes) where stable landmarks are used for orientation:

  1. The anterior contour of the chin just above its maximum convexity
  2. The outline of the inner cortex of the symphysis
  3. The contours of the inferior dental canal
  4. The lower outline of the crypt of the developing third molar (until the roots form).
363
Q

According to Scammon’s Growth Curve, which system displays most rapid growth early in life, then in teenage years?

A

General (Skeletal)

364
Q

What is Facial Neotony / Paedomorphosis?

A

Retention of juvenile features as an adult:

Larger eyes
Small nose
Full lips
Round face

365
Q

What are aspects of aesthetics in the horizontal plane?

A
  • Broad evenness in height between the horizontal thirds

- Lips positioned in the top 1/3 of Lower 1/3

366
Q

What does irregularity index measure?

A

Distance between two contact points. Higher distance equates to higher irregularity

367
Q

What are the 6 steps in Moyer’s Mixed Dentition Analysis?

A
  1. Full M-D width of lower + upper incisors individually
    Then take sum all measurements
  2. Measure the available mandibular + maxillary arch space per quadrant
    (Total = 1-2 + 2-6 per quadrant)
  3. Predict the size of unerupted 3-5s on all quadrants using Moyer’s Table to calculate estimated space needed for permanent 3-5s based on arch incisal width (step 1) + confidence interval
  4. Calculate the space excess/deficiency in each quadrant (Space = Quadrant Arch Length - Incisal width)
  5. Consider the effect of FPM adjustment (depends on terminal plane relationship)
  6. Compute the overall alignment potential
368
Q

What happens if Chronological/Dental/Skeletal ages don’t coincide?

A
  1. Use Chronological Age for Overall Growth and Development
  2. Use Dental Age for Dentoalveolar problems
  3. Use Skeletal Age for Craniofacial Problems

This will determine treatment approaches and timing

369
Q

What trends occur in Inter-Molar width between 12-18 years?

A

Decrease minimally ~1mm (relatively stable)

370
Q

What is the Functional matrix theory of craniofacial growth (Moss Theory) and what evidence supports it?

A

Growth occurs as a response to functional needs and is mediated by the soft tissues in which skeletal bones are embedded.

Evidence:

  • Microcephaly result in small brains and small cranial vaults. - Large eyes result in large orbital cavities.
  • Shrinkage of alveolar ridge after tooth extraction
371
Q

T/F: Females will generally experience tooth eruption earlier than males

372
Q

What indications are there to start orthodontic treatment when there is early permanent dentition?

A

Impacted teeth - can be any teeth
Crowding
Hypodontia

373
Q

T/F: You can have bimaxillary protrusion and still be in a class I skeletal relationship

A

True - as both the maxilla are prognathic in relation to the SNA + SNB angles, but ANB is still within the normal class I range

374
Q

According to the cephalocaudal gradient which body part is most developed at birth?

A

The Cranium (60% developed)

375
Q

What can influence buccal contours (negative space)?

A

Arch width + arch form
Anterior-Posterior Maxillary Position
Inclination of Posterior Teeth
Inter-commissural distance during smiling

376
Q

What is the smile arc?

A

Maxillary incisal edges and curvature of lower lip in a posed smile

377
Q

In order to make a full assessment of a patient, what other information is needed other than arch form discrepancy?

A

Facial Pattern
Soft Tissues
Radiology and Cephalometrics
Maturity Assessment

378
Q

What can cause a central maxillary diastema?

A

1) Ugly Duckling phase - lateral displacement from erupting upper lateral incisor
2) Frenal Pulls

379
Q

What is Class II Flush Terminal Plane relationship?

A

Flush relationship of Mx/Mn Es and where tips of both Cs are edge-to-edge

380
Q

What is the significance of the apical base to orthodontics?

A

The apical base is the area where orthodontic tooth movement occurs

381
Q

What are the pre-emergent tooth positions of successional pre-molars?

A

Should be contained by the all roots of the primary molars

382
Q

How does the dental arch change between 6-12 years of age?

A
  1. Inter-Canine Width
    - Mx: increase is largely through alveolar change, during eruption of the incisors and canines
    - Md: very little change → incisor irregularity
  2. Dental Arch Length
    - Increases up to eruption of permanent incisors and first permanent molars is complete
    - Decreases once leeway space used by canines and premolars
  3. Inter-Molar Width
    - Mx & Md: increase slightly (1-2mm)
383
Q

Where is the Porion (Po)?

A

Soft tissue landmark - The upper margin of the ear canal

384
Q

T/F: Both Mandibular inter-canine width and dental arch length both decrease due to late lower incisor crowding (tertiary crowding)

385
Q

What should be the relationship be between the upper and lower lip and Rickett’s Esthetic Plane (E-Plane)?

A

In normal occlusion:

  1. Lower lip will be closer to E-line than upper lip
  2. At 12-14 years, lower lip to be -2 ± 3mm behind E Plane
386
Q

What is Foster and Hamilton Class III Occlusion?

A

Distal surface of lower 2nd molar in anterior relationship to that of upper 2nd in centric occlusion

387
Q

What direction does the nose grow?

A

Inferior + Anterior

388
Q

T/F: Absolute growth of Lower + Upper Lips exceeds Lower LAFH

389
Q

What permanent teeth do we expect to see at age 11?

A

Upper 3s

Upper and Lower 5s

390
Q

What is the average space of leeway space in both arches?

A 
Mx = 1.5mm/quadrant 
Md = 2.5mm/quadrant
391
Q

What 5 factors can result in premature tooth eruption?

A
  1. Genetic Factors
  2. High Birth Weight
  3. Early Puberty
  4. Endocrine Abnormalities
  5. Early loss of primary teeth through trauma, caries, perio
392
Q

What are two methods of measuring dental age?

A
  1. Eruption Count

2. Nolla Calcification Staging

393
Q

What are the 7 structural signs of mandibular growth rotations?

A
  1. Inclination of Condylar Head
  2. Curvature of Mandibular Canal
  3. Shape of Lower Border of Mandible
  4. Inclination of Mandibular Symphysis
  5. Interincisal Angle
  6. Interpremolar + Intermolar Angles
  7. Anterior Lower Face Height (LFH)
394
Q

What 5 factors aid ideal dental alignment?

A
  1. Use of interdental, primate and leeway spaces
  2. Increased inter-canine width, mainly due to transverse growth
  3. Proclined eruption of permanent incisors, esp Mx, forming a wider arch and increases dental arch length
  4. Appositional growth of alveolar processes in 3 planes (transverse, vertical, anterior-posterior
  5. Appropriate size of apical base and teeth
395
Q

What is a Mesoprosopic facial type?

A

Average face type when referring to extra-oral features

396
Q

Which direction does the ramus grow?

A

Distally - there is significant remodelling of the ramus:

  • Resorption anteriorly to allow for more room in the arch for posterior permanent teeth -
  • Deposition posteriorly
397
Q

What relationship should there be for good aesthetics in embrasures?

A

Embrasures should gradually increase in size the more distal you move

398
Q

What is the growth mechanism of the naso-maxillary complex post natally?

A

Intramembranous Ossification

399
Q

What is juvenile occlusal equilibrium?

A

The slowing rate of eruption once the erupted tooth approaches the occlusal plane. Teeth then erupt at a similar rate to the vertical growth of the ramus to maintain occlusal contact

BDS3 University of Adelaide Dentistry (28 decks)

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