Orthodontics Flashcards

Question

What is the aetiology of crowding? and where do teeth tend to erupt?

Answer 1

In a crowded mouth, upper laterals tend to erupt palatally, lower laterals erupt lingually. Early loss of deciduous molars modified presentation of crowding. > Early loss of Ds = premolar crowding as Cs erupt into Ds space Premolar crowding always due to loss of deciduous molars.

Answer 2

1. Create space for alignment by extracting teeth 2. Create space by expansion of arch laterally (palatal expander) 3) Create space by expansion antero-posteriorly (headgear)

Answer 3

Causes: > teeth too small for arch size > arch too large for normal sized teeth Treated by closing spaces (fixed appliance) or re-distribution of space and fill prosthetically.

Answer 4

Soft tissues (lip, cheeks, tongue) determine the position of tooth crowns. Dental bases determine position of teeth apices/roots 1) Spontaneous alignment of crowded teeth into neutral zone post XLA 2) Partial overjet reduction less stable 3) Everted lips associated with proclined incisors 4) Correlation between size of tongue and angle of incior proclination

Answer 5

Soft tissue factors

Answer 6

Lips meet together at rest without any muscular activity (mentalis muscle)

Answer 7

Half-crown height visible at rest

Answer 8

Growth increases lip competence and reduces overjet

Answer 9

Related to lower lip Influences the positioning of the upper incisors, normally overlaps 3-6mm of crown height - High lip line causes retroclined upper incisors - Low lip line causes proclination of upper incisors, causes unstable overjet reduction (high chance of relapse to previous malocclusion post tx)

Answer 10

Retroclined upper incisors

Answer 11

Proclination of upper incisors, causes unstable overjet reduction (high chance of relapse to previous malocclusion post tx)

Answer 12

Incisor visibility (aesthetic concern for pt)

Answer 13

Increased cheek forces (digit sucking habit) can narrow the upper arch and cause a crossbite

Answer 14

Can cause bimaxillary proclination and anterior open bite presence. Present in Down syndrome patients

Answer 15

Increased mandibular arch width

Answer 16

LAHSAL classification based upon the striped Y diagram Lip, alveolus, hard palate, soft palate, alveolus, lip Cleft palate (CP) Unilateral Cleft lip and palate (UCLP) Bilateral Cleft tip and palate (BCLP) LAHSAL indicates a complete cleft lip and palate.

Answer 17

Common craniofacial malformation 1:700 live births in the UK Male prevalence>female Associated with other syndromes: > Sticklers, Vander Woude, Pierre Robin Sequence, Di George

Answer 18

1. Diagnosis at birth > Specialist nursing contact within 24 hrs > Use of special soft bottles, traditional feeding not possible > Pre-surgical orthopaedics 2. Surgery at 3/12 > Correct muscle layer > Restore functionality 3. Surgery at 6/12 > Close hard palate > Restore velopharyngeal competence (ONF closed) > Allow speech 4. Furlow Palatoplasty to aid with speech 5. Alveolar bone graft surgery due to alveolar clefts > Pre-bone graft ortho = expand upper arch laterally > Corect anterior crossbite 6. Orthodontics with orthognathic surgery > Pts are skeletal class III due to improper maxilla formation > Ortho tx to decompensate incisors > Treat when growth complete

Answer 19

An index used by GDPs to refer paediatric pts to orthodontics by assessing the perceived need for the patient to orthodontic treatment to correct a malocclusion

Answer 20

1. Dental health component (DHC), a 5-point scale 2). Aesthetic component (AC), a 10-point scale

Answer 21

It looks for the single most detrimental occlusal feature in relation to dental health and function. 5 point scale

Answer 22

Aesthetic component assesses impact of psychosocial wellbeing 10 point scale

Answer 23

Pt must be under 18 DHC grade 4 or 5 or DHC 3 with AC of 6 or more Therefore need to IOTN of 3.6 of higher

Answer 24

DHC evidence is incomplete IOTN scores being higher don't necessarily correlate to treatment complexity. AC is very subjective, often many borderline cases

Answer 25

a = overjet h = hypodontia i = impacted d = displacement (contact point displacement or crowding) s = submerged deciduous teeth m = missing teeth

Answer 26

5i. Impeded eruption of teeth (except for third molars) due to crowding, displacement, the presence of supernumerary teeth, retained deciduous teeth or any pathological cause 5h. Extensive hypodontia with restorative implications (>1 tooth missing in any quadrant) requiring pre-restorative orthodontics 5a. Increased overjet >9mm 5m. Reverse overjet >3.5mm with reported masticatory and speech difficulties 5p. Defects of cleft lip and palate and other craniofacial anomalies 5s. Submerged deciduous teeth

Answer 27

- If space for unerupted tooth is <4mm then it is defined as impacted rather than crowded (5i), therefore goes under missing teeth bracket. - Spacing and crowding is not measured unless the tooth deviates from the line of the arch - Submerged teeth not recorded unless only 2 cusps are visible or significant tipping of adjacent tipping of adjacent teeth - Overjet is measure to the most prominent point of the incisors - All 4 incisors must be in lingual occlusion to be recorded as reverse overjet

Answer 28

M = missing teeth (most severe) O = overjet C = crossbites D = displacement of contact points O = overbite including open bite (least severe)

Answer 29

Measure of overall occlusal irregularity, used to assess quality of occlusal outcome compared to initial malocclusion. PAR ruler used to speed assessment. Score specific features and add them up. Pre-tx and post-tx models are recorded to give two PAR scores. PAR nomogram used to compare scores. Used to assess the overall quality of occlusal improvements of orthodontists across the UK.

Answer 30

1st order = in/out labio-lingual position 2nd order = mesio-distal dip 3rd order = tooth inclination or torque

Answer 31

in/out control (labio-lingual) is incorporated into the bracket by variations in bracket base thickness, considering the varying bucco-lingual thickness of the dentition

Answer 32

Tooth angulation (mesio-distal tip) is controlled by the angulation of the arch wire slot. It considers the optimal mesio-distal angulation of each tooth relative to the occlusal plane.

Answer 33

Torque incorporated in the bracket by the angle the bracket base makes with the slot

Answer 34

Disto-gingival aspect

Answer 35

Check no plaque on the teeth, remove if necessary. Cheek retractor (labial sulcus cotton wool rolls) Moisture control is vital before, during and after etching. Place all the brackets in one visit

Answer 36

Correct height (LA point) Correct angulation Correct mesio-distal position > Centre of the bracket base must be positioned approximately over the midpoint of the long axis of the clinical crown (LA point) > Bracket must be in middle of anatomical labial face of the tooth. > Errors of mesio-distal positioning lead to rotational errors of tooth position Each bracket must be at the same distance from the incisal edge or cusp tip as its contralateral tooth.

Answer 37

1. Lower As 2. Upper ABs and lower Bs 3. Ds 4. Cs. 5. Es.

Answer 38

1.Upper and lower 6s 2. Lower 1s 3. Upper 1s, lower 2s. 4. Upper 2s 5. Lower 3s 6. Upper 4s 7. Lower 4s 8 Upper and lower 5s 9. Upper 3s 10. Upper and lower 7s 11. Upper and lower 8s.

Answer 39

16-18 months

Answer 40

12-14 months

Answer 41

20-30 months

Answer 42

11-12 years

Answer 43

9-10 years

Answer 44

10-12 years

Answer 45

10-12 years

Answer 46

11-13 years

Answer 47

11-13 years

Answer 48

17-21 years

Answer 49

17-21 years

Answer 50

- Normal eruption pattern (see overleaf) - Spacing is normal (primate spaces) - Encourage cessation of thumb/finger/dummy sucking before 5 years old

Answer 51

- Severe skeletal discrepancies - Severely delayed dental development - Missing/ supplemental teeth - History of head and neck radiotherapy +/- chemotherapy - Advice for balancing/ compensating extractions

Answer 52

* Normal eruption pattern (see overleaf) * Contralateral teeth should erupt within 6/12 * Midline (median) diastema normal * Maxillary canines palpable at 10 years old

Answer 53

* Severe skeletal patterns where early treatment may be appropriate e.g. developing class II/III * Dental anomalies e.g. double teeth, dens-in-dente, talon cusps * Developmentally missing permanent teeth * Supernumerary teeth * Teeth in unfavourable positions e.g. canines * Impacted first permanent molars * Infraoccluded teeth * Crossbites * Extraction advice where severe crowding evident or first molars have poor prognosis * Advice following trauma to permanent teeth

Answer 54

* Skeletal base acceptable * All permanent teeth present * Class I incisors * Class I molar relationship * Average overjet 2-4mm * Average overbite (1/3rd – ½ lower inc coverage) * Well aligned arches

Answer 55

* Clear-cut IOTN eligible for NHS treatment? > YES (IOTN 3/6 and above) Refer to NHS orthodontic provider > NO (below IOTN 3/6) Discuss private referral to orthodontic provider * Borderline cases (Grade 3 below 3/6) can be referred for NHS assessment as these cases can be difficult toevaluate * Remember, every patient has the right to a secondopinion * Adults may qualify for NHS treatment e.g. if they require complex multidisciplinary care. Otherwise, please refer them to an orthodontic provider for private treatment

Answer 56

If they require complex multidisciplinary care.

Answer 57

The tip of the lower incisors occludes with the middle third of the upper central incisor.

Answer 58

A/P relationship: usually skeletal Class 1 ANB = 3.4 (SNA-SBA) ?? Occurence rate 60%

Answer 59

The mesiobuccal cusp of the maxillary first permanent molar occludes with the mesiobuccal groove of the mandibular first permanent molar.

Answer 60

A mechanism through which the soft tissues produce a more Class 1 incisor relationship when the A-P skeletal pattern is more Class II or Class III.

Answer 61

Biological variation Pathological: condylar hyperplasia Centre line-discrepancies Posterior cross bites and mandibular displacements

Answer 62

Crowding Spacing Local factors: variation in tooth number and form, soft tissue and pathology Abnormalities in position: transposition and ectopic teeth Anterior open-bite: due to increased lower face height Posterior cross-bite

Answer 63

When there is significant movement (>1mm) of the mandible between initial contact in RCP and final position in ICP. RCP = retruded contact position (CR) ICP = intercuspal position (CO) Can be either forward or lateral displacement.

Answer 64

1. Digit sucking habit 2. Narrow maxilla 3. Local problem (often crowding)

Answer 65

The tip of the lower incisors occludes posterior to the cingulum plateau of the upper incisors. Upper central incisors are either normal inclination or proclined.

Answer 66

Increased overjet Occurrence rate 22%?

Answer 67

Aesthetic considerations Functional considerations Dental health (trauma) considerations

Answer 68

Increased risk of trauma, incidence of 44%

Answer 69

Usually a small mandible. Vertical and lateral relationships are often normal. Soft tissue causes: > markedly incompetent lips and a low lower lip resting height > digit sucking, may cause proclination of upper +/- retroclination of lowers.

Answer 70

- anterior open bite (unilateral) - Proclined uppers +/- retroclined lowers - (unilateral) posterior crossbite

Answer 71

Reduce the overbite Reduce the overjet (relieve crowding and align teeth)

Answer 72

URAs tip teeth only. Used for cases then the patient has a minimal overjet and proclined upper labial segment. Because URA retrocline upper incisors, this can lead to pt developing Class II div 2 malocclusion. Due to this URAs are rarely in indicated (unable to bodily move teeth), as well as multiple other conditions often associated with pts that URAs cannot fix.

Answer 73

Removable appliances that harness force from orofacial tissues created by the mandible being in a postured position.

Answer 74

Commonly two stage treatment: functional appliance W fixed appliance. - One stage Tx only indicated in well aligned arches with Class II molar relationship.

Answer 75

Torque control of upper incisors to prevent retroclination. Irregular arch alignment. Rotation Space closure.

Answer 76

The tip of the lower incisors occludes posterior to the cingulum plateau of the upper central incisors, with the upper central incisors retroclined.

Answer 77

Occurrence rate 4.5% Sagittal view (AP relationship) = often mild skeletal class II Vertical relationship = reduced lower facial height Maxillary base much broader than mandible (can cause premolar scissor bite) Well developed chin

Answer 78

- Chin well developed in relation to mandible - Often retrusive lips compared to the nose and chin - normally competent. - Reduced lower facial height common

Answer 79

Aesthetics: dont like appearance of retroclined incisors. Sometimes there is proclination of upper laterals due to lower lip trap? Dental: traumatic overbites require treatment

Answer 80

Either accept incisor relationship and overbite (partial) or Correct incisor relationship to Class I including correction of overbite.

Answer 81

Change in the inter-incisor (I-I) angle. - Lower incisal edge to upper root centroid relationship. - Procline upper and lower incisors to form an occlusal stop. Upper incisor torque needs a fixed appliance and rectangular wire. Extractions often indicated less (or more distal) as we want to keep incisors labially inclined to keep the interincisal angle low and reduce the overbite.

Answer 82

Headgear (EOT) can be used to make the upper buccal segment teeth more distal Can also convert pt to II/1 with a functional appliance (often a twin block) and then use a fixed appliance to finish the case. Orthognathic surgery very uncommon because skeletal pattern usually mild class II.

Answer 83

The tip of the lower incisors occludes anterior to the cingulum plateau of the upper incisors. Occurrence rate 3%?

Answer 84

AP relationship usually Class III, with small maxilla or large mandible. Short anterior cranial base Vertical skeletal feature can be any of average, increased or reduced. Laterally often a narrow maxilla arch or broad mandile, with crossbites often a consequence.

Answer 85

Upper proclined and lowers retroclined

Answer 86

Tendency to have anterior and posterior crossbites due to skeletal features. Anterior crossbite due to Class III incisors. Posterior crossbite due to AP relationship = lower arch broadest parts contacting narrow upper arch parts. Both may be associated with mandibular displacement.

Answer 87

Forward displacement of mandible in ICP can cause wear on labial incisors. Gingival recession on lower incisors Narrow upper arch = crowding

Answer 88

On average people grow 2mm more skeletal class III after the age of 11. Because of this treat pts as late as possible to minimise growth potential.

Answer 89

Mild: procline upper incisors using URA Moderate: procline uppers and retrocline lowers Marked: orthodontic and orthognathic tx

Answer 90

1. Canines are the cornerstone of the dental arch, vital for aesthetics and function. 2. Long roots, meaning good long-term periodontal prognosis 3. Difficult to replace prosthetically (canine guidance)

Answer 91

2-3% of maxillary canines become ectopic. (85% palatally displaced), with 12% associated with lateral incisor root resorption. 0.3% mandibular canines are ectopic.

Answer 92

Crown development begins at age 4-5 months high in the maxilla. Crown calcified at 6-7 years Canines migrate down and forward distal to the root of the lateral incisor Palpable in buccal sulcus aged 10 Erupts 11-12 years old

Answer 93

1. Displacement of dental crypt (space in the alveolar process of a tooth) 2. Long path of eruption 3. Diminutive or missing 2 4. Crowding

Answer 94

Resorption of 2s roots (12%)

Answer 95

1. Not palpable in the buccal sulcus aged 10 2. Cs not mobile 3. Ped shaped lateral incisors 4. Missing lateral incisors 5. Labially inclined lateral incisors (ectopic canines may be placed buccally) 6. Asymmetric loss of Cs 7. Unerupted 3 after 6 months of contralateral 3.

Answer 96

Horizontal or vertical Parallax technique using SLOB - Same Lingual, Opposite Buccal - Parallax = relative movement of the canine in relation to other adjacent teeth when two radiographs are taken with an angle between them

Answer 97

1. 2 x PAs at different angulations 2. Upper occlusal + periapical at different angulation

Answer 98

1) PA and upper standard occlusal 2) DPT and USO

Answer 99

Extraction C/C to create space and balance to maintain centre-line. Ericson and Kurol (1988) found that interceptive C/C extractions in 10-13 year olds will improve 78% of the time if no crowding.

Answer 100

If the 3 only overlaps 2 roots rather than 1 as well. Space is available If pt <14 years old.

Answer 101

patient aged >13 years at diagnosis. Significant crowding If the canine does not improve after 6/12 post XLA of C/C.

Answer 102

1. Height - worse if crown tip of canine at or above the apical third or incisor roots. 2. Mesio-distal position - worse if canine more than halfway across the upper incisor roots. Worse closer to the midline. 3. Angulation - the more horizontal the canine the worse the prognosis.

Answer 103

1. Leave and review 2. Extraction of 3 and orthodontics 3. Exposure and align (open or closed exposure) 4. Create space and replace restoratively: replace with denture, bridge or implant.

Answer 104

> canine hopeless prognosis > C root morphology adequate > Patient doesn't want treatment > Increased risk of surgery in that pt Negatives: ectopic canines become cystic, resorption of Cs, space if Cs exfoliate.

Answer 105

1. Canines hopeless prognosis (very high, close to midline, horizontal angulation) 2. C root morphology adequate 3. Increased risk of surgery in that pt. 4. Pt might not want treatment.

Answer 106

Ectopic canine becomes cystic. Resorption of Cs. Space if Cs exfoliate.

Answer 107

Age, co-operation, oral hygiene and MH must be considered. Used if pt very overcrowded, with good 4-2 contact (reshape 4) Poor prognosis for alignment or lateral resorption risk high.

Answer 108

Canines in favourable position. Sufficient space is available.

Answer 109

Expose crown and leave to erupt for 8-12 weeks before applying fixed orthodontic appliance (traction) - Require thick 19-25 wire to provide anchorage to align exposed canine. Open exposure: remove palatal mucosa and bone, expose tooth and then CoePak (two component material for wound dressing, to cover stitches or to stabilise loose teeth) and suture placed in hole in palate. Closed exposure: especially for buried teeth, canine is exposed, and gold chain attached to bracket on chain, mucosa then grows back over. If canine buccal then need to avoid pulling canine through non-keratinised mucosa. --> either bone bracket and gold chain or use an apically-repositioned flap.

Answer 110

Replace with denture, bridge or implant. Bridges to replace 3 are avoided ideally, poor prognosis.

Answer 111

Space for relief of crowding Space for correction of incisor relationship, mainly for overjet patients. Provision of anchorage to move teeth. (Extractions permit relief of crowding without arch expansion or incisor proclination)

Answer 112

Arch expansion Incisor proclination - Favouarble to avoid as they both take teeth out of the soft tissue neutral zone. - Upper incisor retraction stable, lower incisor proclination tends to relapse. - Premolar extractions make space for incisor retraction. - Often keep pt in class II molar relationship.

Answer 113

1. Health and form of individual teeth 2. To increase stability > usually avoid anterior lower incisor A-P position > Aim to not expand arches laterally to accommodate crowding (except crossbites), as arch expansion not very stable and likely to replase. 3. Amount of space and anchorage required. --> Extracting teeth nearer to the problem created more space and anchorage. --> XLA 4s relieve anterior crowding better than 5s

Answer 114

1. Space near the front teeth, means good anchorage 2. Some spontaneous alignment of crowded incisors 3. Residual space dentally healthy if treatment relapses. 4. Good occlusal fit

Answer 115

If more anterior crowding or bigger overjet.

Answer 116

Central incisor ~9mm Lateral incisor ~7mm Canine ~8mm Premolar ~4mm Molar ~11mm

Answer 117

1. Plan the lower arch first > Mild crowding may not need extractions > Moderate (5-9mm) remove 4s or 5s. > Severe (9+mm) remove 4s 2. Assess tie-break factors > Canine angulation, retroclined 3s need more anchorage to upright > Lip prominence, upright incisors need more anchorage > Incisor inclination 3. Upper arch to fit round lower > Upper arch needs more anchorage normally > Due to upper teeth being larger and overjet reduction normally indicated 4. If lower arch is non-extractino > if upper 4s and XLA and no lower XLA then pt will finish Class II.

Answer 118

1. Pathology 2. Microdontia 3. Macrognathia 4. Missing laterals 5. Peg laterals 6. Extracted teeth causing spacing in arch 7. Mesiodens supernumerary 8. Large labial frenum

Answer 119

Because space is so far from the front of the arch. Means that anchorage is very difficult, 5s most always migrate distally.

Answer 120

Allow 7s to migrate into 6s spaces when 7s start to bifurate.

Answer 121

1. Gross caries and pulpal involvement. 2. Hypoplastic or hypomineralised 3. Large restorations 4. Recurrent caries 5. Lingual or buccal caries.

Answer 122

1. Timing 2. Degree of crowding 3. Mandibular vs Maxillary arch extractions 4. Molar relationship

Answer 123

When bifuration of 7 roots forming, normally around age 10.

Answer 124

Risk of the 5 migrating distally from beneath the E.

Answer 125

Space closure will be incomplete, may cause tipping of 7s.

Answer 126

No crowding - spontaneous closure will not occur. If small amount of premolar crowding present = good prognosis.

Answer 127

Lower arch harder to get final 5-7 contact Upper arch easier due to natural distal angulation of 7 Lower molars converge, upper molars diverge.

Answer 128

Balancing = extractions of a tooth on the opposite side of the same arch, to prevent centre-line discrepancies

Answer 129

Extraction of the same tooth in the opposite arch, to preserve buccal segment relationships (molar relationship) and prevent over-eruption.

Answer 130

No! loss of a 6 is too far from the midline

Answer 131

Yes! - compensating is required if over eruption of opposite 6 likely and help maintain molar relationship.

Answer 132

Yes, as no occlusal stop, as upper 6s lie posterior to lower 6s. Upper 6s with over erupt more than lowers.

Answer 133

Lower 7s tip mesially and roll lingually. Upper 7s rotate around palatal root. Poor contacts if incomplete closure Stagnation areas Spacing Necking of the alveolar bone

Answer 134

Extractions undertaken to minimise or eliminate the severity of the developing malocclusion or eliminate potentially harmful occlusion before damage occurs. 1. To guide the eruption of permanent successors 2. To encourage space closure in hypodontia 3. To reduce localised gingival recession 4. Preserving symmetry and molar relationship 5. Impacted 6s

Answer 135

> Unerupted upper incisors (ensure its not a differential diagnosis), extract delayed exfoliating deciduous incisors. > Palatally erupted upper 2: if anterior dentition very crowded then XLA C/C before the 2s reach the occlusal level (moves crowding to the C region) > Unerupted lingual lower incisors: normally due to retained deciduous incisors (XLA of deciduous incisors) > Ectopic canines, XLA of Cs > Submerged tooth: infra-occluded deciduous teeth, normally due to absent permanent successor

Answer 136

Common if 2 or 5 missing

Answer 137

> XLA C/C if crowding and gingival recession of one lower incisor present. > Soft tissue moves the incisors into the neutral zone. > Gingival recession in the crowded dentition due to teeth erupting outside the neutral zone.

Answer 138

> Lower incisor crowding can cause a 2 root to resorb a C, resulting in premature exfoliation. > This can result in a centreline shift to the affected side. > To prevent this happening a balancing extraction of the contralateral C must be done. > only ever needs to be one balancing extraction in every arch. > The further from the midline the smaller the effect on the centre line > The further from the midline the greater the effect on molar relationship

Answer 139

May require XLA of D or E to allow the impacted 6s to upright naturally.

Answer 140

Teeth that fail to maintain their occlusal relationship with opposing or adjacent teeth. Most commonly affects the deciduous mandibular molars (8-14%)

Answer 141

The occlusal surface of the tooth is above the contact point of the adjacent tooth.

Answer 142

The occlusal surface of the tooth is at the contact point of the adjacent tooth

Answer 143

The occlusal surface of the tooth is below the contact point of the adjacent tooth

Answer 144

- Permanent success absent (ortho tx), to allow teeth to align spontaneously - Severe submergence, approaching gingival level - Adjacent teeth tipping above the tooth

Answer 145

Can potentially build up with onlays if patient is older and submergence has stopped.

Answer 146

When there are equal forces in opposite directions

Answer 147

1. Applies mechanical force couple to the crown > Tipping movement = removable appliance i. achieves tipping movement of tooth around the centroid ii. Centroid = centre of resistance. > Bodily movement = fixed appliance i. overcomes tendency to tip - tooth moves bodily by the force couple. > Rotation movements i. force couple applied on the centre of resistance in horizontal plane ii. achieves controlled tooth movement such as derotation. 2. Allows precise control over nature and direction of forces applied. 3. Forces are applied through interactions between components such as arch wires, brackets and auxilliaries.

Answer 148

- Archwires: multiple metals (nickel titanim), either round or rectangular > pre-formed shape, then this shape either accepted or adapted. - Brackets: twin or self-ligating > identifying marker is distal and gingival - Auxiliaries > Niti springs > Power chains > Elastic bands

Answer 149

Derotation Torque movements - require rectangular wire to grip bracket slot and apply force couple Bodily movements - Centreline correction - Controlled space closure - Overjet reduction

Answer 150

1. Levelling and alignment - archwire small diameter, flexible, high elastic limit - nicket titanium - 0.012 or 0.014 - if brackets correctly positioned a flat archwire will align teeth correctly 2. Overbite reduction - rigid archwire of large dimensions - stainless steel - round or rectangular - 0.019 x 0.025 3. Overjet reduction - Rigid archwire of large dimensions - stainless steel, rectangular - 0.019 x 0.025 - provides bodily control in all planes 4. Space closure - Rigid archwire of large dimensions - stainless steel, rectangular 0.019 x 0.025 - provides bodily control in all planes - need to prevent teeth tipping into the space 5. Finishing procedures - Small diameter archwires, thin, round stainless steel.

Answer 151

Appliance related issues: 1. gingival inflammation 2. decalcification 3. root resorption 4. soft tissue trauma Patient related issue 1. breakages 2. attendance 3. poor oral hygiene 4. caries 5. staining

Answer 152

They utilise forces generated by soft tissues to move teeth - They posture the mandible away from rest position - Forces are therefore generated by the resulting soft tissue stretch - They increase growth potential

Answer 153

Mainly treat pts with Class II div 1 incisor relationship, with or without crowding, on a moderate to severe skeletal class II base Can use it for Class II div 2 pts but must convert to class II div 1 first to treat

Answer 154

1. Myodynamic > Forces are generated by stimulation of the masticatory muscles > Twin block or Bionator 2. Myotonic > Elastic recoil within the stretched forces generates force > Harvoid

Answer 155

- Retraction of upper incisors (palatal tipping) - Distal movement of the upper buccal segment (molar relationship correction) - Proclination of lower incisors - Overbite reduction by reducing lower incisor eruption while permitting buccal segment tooth eruption - Mesial movement of lower buccal segment

Answer 156

Mandibular growth enhanced by 1mm average Maxillary growth inhibited by 1mm average - Wide variation of these effects 3 theories as to the location of change in skeletal effects 1. More actual mandible growth 2. Change in position of the glenoid fossa 3. Change in direction of growth

Answer 157

Frankel has proposed that a functional appliance + lip exercises = alter lip and cheek position. Soft tissue encourage to be correctly positioned, with normal function.

Answer 158

Growing patient, as they are better tolerated in younger patients. Late mixed/early permanent dentition, but can be used at later stage. Girls 10-12, boys 12-14 as can influence growth a little more when pt growing rapidly.

Answer 159

1. Clark Twin Block > Two-part appliance > Well tolerate 2. Bionator > Single piece > not retentive (relies on pt biting to maintain position > used for mixed dentition mainly 3. Frankel > Single piece > not well tolerate > expensive and v fragile 4. Harvoid > Less A-P posture, more vertical effects > Not retentive and not well tolerated.

Answer 160

- Patient can eat with the appliances. That even increased the speed of appliance work - Initial soft diet of eggs, soup and boiled vegetables suggested. - Increased salivation at the beginning of wear - Suggested to be worn at least 18 hrs. a day especially during sleep. - Brush the appliance at least once a day with water and soft toothbrush

Answer 161

Upper and lower impressions Bite record

Answer 162

- Do they come in wearing it? - Is speech normal? - Does it look worn? - Slight gingival inflammation may be present? - Can they insert and remove it with ease? - Lateral open bites appear often? - Are the active components more passive? - Has progress been made? > Check overjet, as should reduce by > 1mm per month > Molar relationship should improve > Lateral open bites appear often > Radiographs alongside specialist training to identify success or failure

Answer 163

No intercanine growth above 10 years old, therefore spontaneous resolving of anterior crowding not possible after this.

Answer 164

Mandible grows more compared to maxilla on average > AP skeletal pattern measured by ANB angle ANB angle gets smaller by 1 degree from 11 to 20. However there is a standard deviation of 2.5 degrees. - 15% grow more class III by >3.5 degrees - 15% grow more class II by > 3.5 degrees MOST PEOPLE HAVE A JAW RELATIONSHIP WHICH STAYS THE SAME WITH GROWTH

Answer 165

1. Cartilage replacement - Cranial bases synchondroses - Mandibular condyles - resistant to the effects or applied forces, working entirely genetically. 2. Membranous growth - Periosteal activity at surface and at sutures - All other cranial and facial growth - Influenced by pressure and tnesion, like periodontal remodelling in response to orthodontic forces.

Answer 166

> Headgear and functional appliances restrain maxillary growth (membranous growth) > Traction to skeletal anchorage can increase midface growth - These include bollard mini plates and Class III elastics - Average enhancement = 4mm > Mandible less amenable to growth modification - FA enhance growth of mandible by 1-2mm in growing patient

Answer 167

anterior open bite

Answer 168

- Class III patients treated late as growth unfavourable - Class II patients treated earlier as growth favourable

Answer 169

After growth stopped Orthognathic surgery + 4 yrs. after growth has stopped. Implant surgery at around 23 yrs. old

Answer 170

Girls - 10-12. Growth stops age 16 Boys - 12-14. Growth stops age 18

Answer 171

1. Do you need to treat the patient? 2. The patients wish list, what do they want from the treatment? 3. Occlusal relationship aims — usually Class I incisors and molars 4. Where in the face should occlusion be put? - Usually try not to move lower incisors substantially forwards or backwards - Try not to expand the arches very much - Both changes make stability less likely 5. Choice of appliance depends on clinical and patient factors 6. Extractions: need and choice of extraction Collection of data --> Problem List --> Treatment aims and means 1. Gathering data 2. Compiling a problem list 3. Deciding treatment AIMS 4. Deciding treatment MEANS

Answer 172

= if the lips meet at rest without muscular activity - important for stability of overjet reduction - if they are incompetent, then overjet reduction more unstable.

Answer 173

Mild = 1-4mm Moderate = 5-8mm Severe = 8+mm Labial and buccal segment crowding. Crowding mesial to canine is labial, distal is buccal.

Answer 174

- Incisor classification - Overjet - Overbite > normal, increased, reduced AOB > incomplete or complete overbite - Centre-line discrepancies

Answer 175

- Class I = MB cusp of first molar lies in the buccal groove of the lower first molar - Class II = MB cusp U6 lies anterior to the buccal groove of L6 - Class III = MB cusp lies posterior to the buccal groove of L6 Units in terms of premolars. full unit, 1/2 unit, 1/4 unit?

Answer 176

Combined orthodontic and surgical treatment, due to the problem being so severe that orthodontics alone cannot provide solution Treatment carried out when facial growth is complete or almost complete Plan the procedure by cephalometric planning and treatment simulation > Superimposition of bony segments over original lat-ceph > Computer prediction from digital lat-ceph radiographs > Superimpose both the profiles on top of each other, analysing planned changes

Answer 177

1. Correction of antero-posterior relationships - Mandible can be moved both forwards and backwards to correct - Maxilla can only be moved forwards due to posterior skeletal interference - Retrognathic mandible corrected by sagittal split osteotomy surgery 2. Correction of vertical relationship - Long lower face height associated with AOB - Short lower face height associated with deep traumatic overbite - Maxilla movement: intrusion successful, extrusion unpredictable - Mandible can be moved up or down anteriorly - Downward movement of mandible at the gonial angle unstable 3. Correction of transverse relationship - Surgical expansion of the maxilla possible - Difficult in the mandible due to temporo mandibular articulation 4. Genioplasty The chin can be moved in all 3 planes - Aesthetically better results if the bony movement increases soft tissue support - Inferior border osteotomy to correct protrusive mental bone

Answer 178

1. Presurgical orthodontic treatment (orthodontic decompensation) - Arch alignment - Normal inclinations of upper and lower labial segments - Upper arch expansion (co-ordination of arch widths post-surgery) - Once orthodontic decompensation has been achieved the malocclusion will often appear substantially worse, reflecting underlying skeletal discrepancy 2. Surgical management - 2-3-hour op, in hospital 1-3 days post-op and then 2-3 weeks home recovery 3. Post-surgical orthodontic treatment - 3-8 months 4. Orthodontic retention

Answer 179

1. Correct molar relationship (Class I) 2. Correct crown angulation 3. Correct crown inclination 4. No rotations 5. Flat occlusal plane 6. Tight interproximal contacts (no spaces)

Answer 180

Resistance which prevents unwanted reciprocal tooth movement (Tooth moving forces create equal and opposite forces, reciprocal forces must be resisted to minimise unwanted reciprocal tooth movement)

Answer 181

1. Teeth in the same arch 2. Oral mucosa and underlying bone 3. Opposing teeth (intermaxillary traction) 4. Extra-oral anchorage 5. Temporary Anchorage Device (TADs)

Answer 182

- Ways to just move anterior teeth, preventing loss of space by posteriors moving mesially 1. Move few teeth at once 2. Keep active forces minimal 3. Make anchorage root area as large as possible (XLA of 4s and incorporate 7s in unit) Teeth bodily moved require more anchorage, than teeth being tipped as bone must be resorbed over a much larger surface area Teeth free to tip move very easily due to the small root surface area and minimal force needed - Bodily movement requires much more anchorage than tipping - Due to bodily movements needing to resorb bone over large surface area - Intermaxillary elastics provide anchorage (traction) for space closure Extra-oral anchorage: force resisted by the bones of the head, a very large anchorage - Headgear used as extra-oral anchorage - Used when there is not enough intra-oral anchorage or to move all teeth distally TADs: a potentially infinite anchorage source - Avoids the spring pushing the upper front teeth forwards (loss of anchorage) They contain no PDL, meaning that forces applied on them do not invoke a cellular response to move a tooth

Answer 183

Presence Position Pathology

Answer 184

A standardized lateral view of the facial bones, base of skull, soft tissues and cervical spine. - 2D assessment of upper and lower jaws relative to cranial base - Assessment of tooth inclinations - Identification of ectopic teeth - Implant planning - Baseline for monitoring growth

Answer 185

ANS --anterior nasal spine PNS -- posterior nasal spine Maxillary-mandibular planes angle N -- Nasion, most anterior point on frontonasal suture S --- Sella, midpoint of Sella turcica, the saddle shaped depression in the sphenoid bone ME -- Menton, lowest point on mandibular symphysis GO --- Gonian, the most inferior point on the angle of the mandible

Answer 186

Removable appliances can only tip teeth, they are unable to perform bodily movements Current uses of removable appliances - Simple tooth movements - Space maintenance - Retainers for post-orthodontic treatment Functional appliances

Answer 187

ARAB 1. Active component i. springs ii. labial bows iii. screws iv. z springs? 2. Retentive component i. adams clasps (0.7mm ss wire posteriorly) ii. southend clasp (0.7mm ss wire anteriorly) 3. Anchorage 4. Baseplate i. holds appliance together ii. provides anchorage from vault of palate iii. can provide anterior and posterior bite planes

Answer 188

i. length of spring (increased length = greater force) ii. elastic modulus of wire (decreased elasticity = greater force) iii. thickness of the wire (increased thickness = greater force)

Answer 189

Reverse looped bow in 0.8mm ss wire Can be used as a retainer - Or split in two and used as a retractor

Answer 190

Used for unilateral and bilateral distal movement Used for arch expansion Turn once or twice a week for optimal results

Answer 191

Relapse: return of the original malocclusion following correction

Answer 192

Stability: the dentition existing in a state of equilibrium between forces imparted by soft tissues of the lips, cheeks and tongue

Answer 193

> Retention: the phase following active orthodontic treatment, aimed at stabilization of the orthodontic correction

Answer 194

Soft tissue Occlusal factors Facial growth Supporting tissues

Answer 195

> Teeth not in neutral zone unstable, only stable if new balance found > Reducing overjet in Class II div 1, stable if lower lip in front of upper incisors post Tx > Unstable if short lips present, whereby lower lip doesn’t cover the upper incisors

Answer 196

> Adequate overbite must be reached in Class III cases > Appropriate inter-incisal angle in Class II div 1 cases (133 degrees) > Good intercuspation must be achieved in all cases

Answer 197

> Class III skeletal pattern growth may worsen with facial growth > Over-correction in Class II and III patients - Lower incisor crowding - Anterior open bites may worsen with backward growth rotation - Deep bites may worsen with forward growth rotation

Answer 198

Bone > Newly formed osteoid and immature woven bone more susceptible to remodelling, has critical period of 3 months Periodontal ligament > Avoid ‘spring back’ post-treatment Sharpey fibres between cementum and bone require 1-2 months to re-organise Gingiva > Supra-crestal fibres require 6 months to re-organise > Free gingival fibres require 12 months to re-organise > Derotation during orthodontics most prone to relapse (prevented by circumferential supracrestal fiberotomy)

Answer 199

Fixed: wire attached to the teeth with composite, used in more unstable situations Removable: vacuum formed retainers (VFRs) and Hawley type retainers