Orthodontics Flashcards
1
Q
Risk & Benefits-
Patient has an anterior crossbite and requires fixed appliance treatment.
1. Name 4 fluoride supplements you would give the patient to prevent decalcification, naming the dose and frequency? (4)
A
- Fluoride toothpaste- dose depending on age- 2,800ppm or 5,000ppm (16+) in high risk patients or else 1,450ppm
- Fluoride varnish 22,600 ppm up to 4x yearly
- Fluoride mouthwash 225ppm x1 daily (0.05%
- Fluoride tablet 1mg x1 daily
2
Q
Name other methods to prevent decalcification other than fluoride supplementation? (2)
A
- Ensure correct case selection and only perform orthodontics on patient who have good OH or are motivated to achieve good Oh during treatment (motivation, Oh and caries risk key factors for consideration)
- OHI- correct toothbrushing and interdental brushing beneath the wires and around brackets twice daily and after meals, use disclosing tablets to focus on missed areas
- Dietary advice- reduce sugar and try to keep to mealtimes, drink water between meals and avoid carbonated drinks which could reduce pH
- Regular hygiene appointment at GDP
- Fissure sealants
- Chew sugar free gum to stimulate saliva flow
3
Q
- List 8 potential risk of orthodontic treatment other than decalcification? (4)
A
- Root resorption
- Gingival recession
- Relapse
- Soft tissue trauma
- Loss of vitality
- Loss of periodontal support
- Wear of opposing teeth from brackets- enamel fracture and wear
- Poor/failed treatment
- Allergy
Invasive as etch the tooth surface.
4
Q
Planned Extraction of FPM-
1. What are the advantages of planned extraction of first permanent molars? (4)
A
- Spontaneous space closure
- Caries free dentition
- Reduction in possible orthodontic needs
- Mild buccal segment crowding
5
Q
What sings are indicative of suitability/appropriate timing for extraction of FPM?
A
- Start of calcification of the bifurcation of the lower second molars 7’s
- Ideally all premolars and 8’s present
6
Q
Name 2 disadvantages of planned Extraction of FPM?
A
- Traumatising to the child and may become dentally anxious after. Requiring further surgical treatment
- May require a GA if child is young and the risks assocaited with this
- Possible distal migration of the 5 and tipping of the 7
7
Q
Adult Orthodontics-
Trevor is 25 years old and attends your practice complaining that his upper from teeth are slightly crooked and he wants them straightened. He declined orthodontic treatment as a teenager. Clinical examination reveals red marginal gingivitis but an otherwise caries-free unrestored dentition. Clinical investigation shows he has a Class I skeletal pattern with a Class II Division I incisor relationship with proclined upper incisors and he has mild upper anterior crowding. You refer Trevor to an orthodontist.
1. What information, relevant to his provision of orthodontic care, do you need to provide the orthodontist? (5)
A
- Patient details- name, DOB, sex, CHI, address
- HPC, RMH, RDH
- Patient expectations
- Incisor relationship, Skeletal base relationship (AP, vertical & transverse)
- Teeth present/absent, OH, prognosis of teeth
- Incisor inclination and crowding of lower and upper arch
- OJ, OB, centrelines, molars relationship, canines relationship, crossbite
- IOTN score
- Any radiographs, study models or clinical photographs taken
8
Q
The orthodontist decides to undertake treatment for Trevor. Trevor attends for a routine check-up with you halfway through orthodontic treatment You notice a debonded bracket and demineralisation around the remaining brackets. How would you manage each of these problems?
A
- Account for all components- does patient know where debonded bracket is? What happened? (if possible aspiration risk refer to A&E)
- Don’t attempt to rebond bracket as don’t know prescription and if rebond in wrong place can cause issues or worsening of malocclusion
- If on rounded arch wire remove ligature and bracket from wire, tell patient how to clean tooth and refer back to orthodontist
- If on square arch wire can’t remove bracket to simply tell patient it has debonded but out with your remit to rebond it, make sure ligature is secure, inform patient to slide bracket to side to clean tooth and to get an appointment with orthodontist as soon as possible
- Inform patient of demineralisation and explain what it is, the potential long term effects and how it can be prevented
- Give OHI regarding fluoride; prescribe high fluoride toothpaste and give targeted toothbrushing advice
- Apply fluoride varnish 22,600ppm to areas of demineralisation
- Refer back to orthodontist for replacement of bracket
9
Q
- When Trevor next visits the orthodontist the appliance is remove because of his poor compliance. Trevor returns to your about other treatment options. One possible treatment would be extraction of the upper incisor teeth and provision of an upper partial denture. What would be the potential long term risks of
a) Loss of the upper incisor teeth (3 marks)
A
- Bone loss
- Drfting and mesial tipping of adjacent teeth
- Difficulty with speech
- Difficulty with mastication
- Poor labial profile
10
Q
- When Trevor next visits the orthodontist the appliance is remove because of his poor compliance. Trevor returns to your about other treatment options. One possible treatment would be extraction of the upper incisor teeth and provision of an upper partial denture. What would be the potential implications of
a) Provision of an upper removable partial denture (3 marks)
A
- If patient has poor compliance and OH and this is a potential plaque retentive factor so increased caries risk
- Poor aesthetics
- Psychological and psychosocial impact of wearing denture
- Hard to wear and function in terms of mastication
11
Q
- Trevor doesn’t want to wear a denture and thinks that crowns should be provided. Why would you advice against this options? (1)
A
- As he has poor OH and crowns require good Oh to keep in good condition as can be difficult to clean and poor OH can result in gingival recession, perio disease and unstable, unaesthetic crowns. Requirinf early loss of teeth
- Crown preperations are destructive and require removal of alot of tooth tissue
12
Q
- What advice would you give to Trevor to maintain his oral health in the long-term?
If he has poor OH.
A
- Standard OHI
- Brush 2x daily with electric TB (using the modified bass techique)
- High risk so high F TP (5000ppm)
- Spit dont rinse
- Brush for 2mins
- Use ID brushes and or floss once a day
- Single tuffed brush to get back of lone standing tooth
- Disclosing tablets for seeing areas to focus on
- Attend dentist regularly
- Minimise sugar in diet
13
Q
30-year-old patient presents, worries about his class 3 incisor relationship.
1. How would you assess the patient Ap relationship? (3
A
- Visual assessment - frankfort plane parallel to the floor
- Palpate the skeletal bases - direct palpitation I/O with fingers
- Lateral ceph
14
Q
- Name four special investigations that an orthodontist would do? (2)
A
- Study models
- Radiographs OPT and lateral ceph
- Clinical photographs
- Sensibility test
15
Q
30-year-old patient presents, worries about his class 3 incisor relationship.
3. Name four intra-oral features that this patient might have? (4)
A
- Proclined upper incisors
- Retroclined lower
- reduced OJ/Reversed OJ
- Reduced OB or possible AOB
- Anterior or posterior buccal crossbites (Due to smaller maxilla)
- Maxillary crowdind (due to smaller maxilla)
- Tendency for displacement on closure
16
Q
- What systemic condition might the patient have if his mandible keeps growing? (1)
A
Acromegaly as the patient is 30 years old otherwise would be giantism
Acromegaly is a disorder that occurs when your body makes too much growth hormone (GH). Produced mainly in the pituitary gland, GH controls the physical growth of the body. In adults, too much of this hormone causes bones, cartilage, body organs, and other tissues to increase in size.
17
Q
- What are the classes of AP relationship?
A
- Class I- maxilla 2-3mm in front of mandible (ANB 2-4°)
- Class II- maxilla more than 2-3mm in front of mandible (ANB> 4°)
- Class III- mandible in front of maxilla (ANB<2°)
18
Q
Describe a class 3 incisor relationship?
A
When the lower incisors meet anterior to the cingulum plateu of the upper incisors
The OJ is reduced or reversed
19
Q
- How is a class III malocclusion managed?
A
- Accept
- Intercept early with URA correction of the incisor relationship and crossbite
- Growth modifcation with a functional (reveresed twin block or Frankel lll) chin cup, head gear with RME to reduce and redirect mandibular growth and encourage maxillary growth and then fixed appliance
- Camoflague - accept underlying skeletal pattern and correct incisor relationship
- Surgery and fixed appliance for functional, speech, mastication or aesthetic concerns
20
Q
Digit Sucking-
1. Give 4 intra-oral signs of thumb sucking/ non nutritive sucking habit?
A
- Proclination of the ULS
- Retroclination of the LLS
- Small Maxilla Posterior crossbite
- Localised anterior OB or incomplete OB
21
Q
- Explain the effects of prolonged digit sucking habit on posterior dentition?
A
The thumb or finger is in the mouth and forces the tongue down. This results in an inbalance of force between the cheek muscles (buccinator) and the tongue. Causing the maxilla to be more narrow and this results in a posterior crossbite
22
Q
- Give 4 methods of stopping a digit sucking habit?
A
- Positive reinforcement
- Non-appliance home cessation/ deterrents- plaster on fingers, preventative nail varnish, gloves, cellotape
- Removable habit break appliance
- Fixed appliance with anterior rake habit breaker (quad helix)
23
Q
- What additions can be made to a URA to break the digit sucking habit?
A
- Deterrent rake
- Hawley retainer thumb appliance
- Palatal crib
- Bluegrass appliance
24
Q
Patient with a NNSH presents with Class 2 Div 1 incisors and increased OJ.
1. What are 4 intra-oral sings of thumb sucking?
A
- Proclined upper incisors
- Retroclined lower incisors
- Small maxilla so posterior crossbite
- AOB or reduced OB
25
2. What is the BSI incisor classification of Class 2 Div 1?
When the lower incisors meet below the upper incisor cingulum plateu.
Then the upper incisors are of average or proclined
Resulting in an increased OJ
26
3. Functional appliance was used and successfully reduced the OJ. Give 8 changes or ways it did this.
* Mandible postured forward from its normal rest position
* Skeletal changes- facial musculature stretched (acts to pull upper dentition back) which generates forces transmitted to the teeth and alveolus and acts to restricts maxillary growth, meanwhile mandibular growth is encouraged as condyle are distracted and so encouraged to remodel which encourages mandibular growth, glenoid fossa also remodels (new floor of glenoid fossa formed) to grow forwards
* Dental changes- teeth held in edge to edge position, lower incisors are tipped forward (proclined) and lower molars mesialised by action of the lower block and musculature forces, upper incisors are tipped backwards (retroclined) and upper molars distalised by the action of the upper block and musculature forces
* Also disengages the occlusion
* Must be worn all the time
27
Cleft Lip & Palate-
1. What is the incidence of cleft lip and palate in the UK?
1 in 700 live births
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2. What are the general health implications of CLP?
Difficulties with
- Speech (air escapes during certain sounds hypernasality)
- Mastication
- aesthetics
- Hearing problems (problems with ear development)
- Potential airway blockage/ respiratory problems
- Often assocaited with other anomalies such as cardiac anomalies
- Increased risk of infection due to connection with nasal and oral cavity
29
What are the dental features for CLP
- Missing teeth (hypodontia)
- Sizes of teeth (mircodontia)
- Supernumeraries
- Ectopic position
- Hypoplastic
- Crowding due to the small maxilla
- Impacted teeth
- Class 3 growth pattern
30
4. Outline 5 treatment stages for CLP patient?
- Lip closure at 3 months
- Palatal closure at 9 months
- Bone graft 8-10years
- Definative ortho 12-15years
- Revision Surgery 18-20 years
31
Name 5 members of the CLP MDT?
- Clef surgeon MAXFAX surgeon
- ENT
- Clef nurse
- Orthodontist * Dental team- paediatric dentist, orthodontist and orthodontic therapist, restorative dentist, oral surgeon, dental therapist
- Speech therapist
- Clinical pyschologist
32
Orthodontic Complications-
1. What are the common complications of orthodontics? and how is each one managed?
- Decalcification (Hard to manage once happens, so prevention is the best. Good OH, give dietary advice on sugar reduction and use of sugar free gum, encourage fluoride exposure via toothpaste, mouthwash and duraphat varnish)
- Relapse ( patients are given a retainer to retain the position of the teeth and prevent relapse to malocclusion. This can be a bonded fixed retainer or removable thermoplastic)
- Root resorption (Explain to the patient inevitable consequence of tooth movement but generally minimal and only 1-2mm over 2 years for FA. increased risk with high force of movement (hence avoid excessive orthodontic forces), previous trauma or blunt, short or pipetted root form (radiograph before to warn patient if risk increased as a result of this)
- Gingival recession (Adult patients should be made aware this a normal and somewhat Unpredicatbel risk, can be exacerbated by poor OH so ensure patient is aware of importance of good OH and give appropriate instruction on how to achieve this, also make patients aware this is exacerbate in cases of harsh toothbrushing or thin biotype)
33
Give 3 other linked complications of ortho tx?
## Footnote
Apart from root resopriton, relapse, decalcification, gingival recession
- Loss of vitality
- Soft tissue trauma
- Loss of periodontal support
- Enamel fracture
- Failed tx
34
Lateral Cephalometry-
1. In the lateral cephalometry- what are the SNA, SNB and ANB?
SNA - is the angle between the cranial base and the maxilla in an AP relationship (angle between mid-point of sella tursica, nasion and deepest concavity anteriorly on the maxillary alveolus)
SNB - is the nagle between the cranial base and the mandible in a AP relationship (angle between mid-point of sella tursica, nasion and deepest concavity anteriorly on the mandibular symphysis)
ANB - Is the difference between the maxilla and the mandible
35
2. What are the average values for a Caucasian? on a lateral ceph.
SNA - 81 +/- 3
SNB - 78 +/- 3
ANB - 3+/-2
36
WHat is the average FMPA angle?
* 27 +/- 4°
37
4. What is average incisors inclination?
* Upper- 109 +/- 6°
* Lower- 93 +/- 6°
38
5. What is ANB for Class II and Class III patients?
* Class II- >4°
* Class III- <2°
39
Give the average value for LAFH and interincisal angle for lateral ceph?
LAFH - 55%
Interincisal angle - 135 degrees
40
Diastema-
1. Give 4 reasons for a diastema?
-Hypodontia (congential missing 2's)
- Supernumerary Midline - tuberculate mesiodens
- Developmental
- Prominent/low frenum
- Pathological causes
- Generalised Spacing
- Proclined uppers
41
2. How are diastemas managed?
- Accept and monitor
- Generally tx determined by the cause of the diastema
- Possible surgical removal of the supernumerary
- Early closure if severe and child is concerned - central may be pulled together and a bonded retainer used to prevent relapse (then if missing laterals these can be replaced)
- Fraenectomy may be indication if prominent frenum
- For proclined uppers URA to tip back
- For generalised spacing then ortho FA
- Pathology should be dealt with by oral surgery or oral medicine or MAXFAX
- Bonded retainer will always be required following tx as prone to relapse
42
3. How is a posterior crossbite managed and write a prescription?
- URA with mid palatal screw
Please construct a URA to expand the upper arch
A - mid palatal screw (screw turned 1/2 a turn a week)
R - Adams clasp on 6's 0.7mm HSSW and on URd and ULd 0.6mm HSSW
A - check
B - self cure PMMA with Posterior bite plane
43
How else can you manage a Posterior crossbite? apart from URA mid palatal screw
- Quadhelix with bands on the 6's
- Rapid maxillary expansion appliance
44
5. What teeth are most commonly infraoccluded?
lower ds (8-14%)
45
6. How will they appear clinically and radiographically? Infra-occluded teeth
Clinically
- Appear submerged
- When tap have a dull precussion note
- No mobility
Radiographically
- blurred or absent PDL (ERR?)
46
7. What are your treatment options for a infra occluded tooth?
Check if their is a permenant successor
* If permanent successor is present- monitor and observe for 1 year as generally exfoliate normally, consider extraction only if contact points going sub-gingival or root formation of successor is near completion
* If permanent successor is absent- retain if in good condition and either place only or build up to occlusal level with composite, extract when only 1mm of crown showing (to avoid going sub gingivally) or when patient can no longer effectively clean it and plan space management (either leave with gap as non-aesthetic tooth or replace with bridge etc)
47
8. What percentage of 6-year-olds, 11-year-olds and 18-year-olds have diastema?
6 year olds - 98%
11 YO - 49%
18 YO - 7%
48
9. What factors determine the management of infra-occluded teeth?
- Presence of successor
- Prognosis of the tooth
- OH levels of the patient
- Patients wishes
- Degree of infra-occlusion
49
Fixed Appliances-
1. Name 4 component of fixed appliances?
- Bracket
- Ligature
- Wire
- Bands
- Anchorage components
- Force generating components
50
2. How does tooth movement work in terms of FA?
- When an external force is applied to a tooth, The PDL mediates remodelling of the bone around the tooth which allows the tooth to move(NB. Ankylosed teeth will not move)
- In orthodontics, forces applied casue recruitment and activation of osteoclasts and osteoblasts which allow bone remodelling
- There are three proposed mechanisms for how this works at a cellular level. Differential pressure theory, pizo-electric theory and mechano-chemical theory.
- The exact mechanisms depends on the appliance and the type of tooth movement
- FA works mainly by bodily movements
- Bodily movements involved frontal resorption, in response to light forces applied by appliance there is hyperaemia within the PDL and recruitment of osteoclasts and osteblasts. On the pressure side (direction in which the tooth is moving) there is resorption of the lamina dure and bone via osteoclasts (this is known as frontal resorption) while on the tension side (direction away from which the tooth is moving) there is apposition of osteoid via osteoblasts, this results in complete remodelling of the socket and movement of the tooth.
N.B Osteoclasts cannot tell what is bone and what is cementum hence cementum will also be resorbed hence all patients will get warned of the risk of root resorption. However cementum is much more resistant to resorption than bone hence the normally small degree of resorption
51
3. Give 4 methods of anchorage?
- Base plate
- TAD
- Elastics
- Transpalatal arch wire
52
Crossbites-
Patient attends with an anterior crossbite involving 21.
1. When is the best time to begin treatment?
- Intercept it as soon as possible
- With URA
- The earlier the better
53
2. What 3 features of the malocclusion would make it amenable to treatment with a URA?
| Patient attends with an anterior crossbite involving 21.
- Upper tooth is palatally tipped. This means there is more room for labial tipping
- Increased OB - Aids stability
- Adequate space to move teeth forward
- Only 1 tooth movement required
54
3. Design a URA for fixing an anterior crossbite involving 21? NB. Pay attention to
Please construct a URA to correct an anterior crossbite of the 21
A - Z spring on 21, 0.5mm HSSW
R - Adams clasps on the 6's 0.7mm HSSW and the D's 0.6mm HSSW
A - Fine
B - Self cure PMMA with flat posterior bite plane
55
4. What 5 factors resist disapclement forces?
- Mastication
- Speech
- Tongue
- Gravity
- Active component
56
Orthodontic Terms-
Describe and give values for the following terms-
1. Overjet-
* Horizontal relationship (degree of overlap) between the maxillary incisors and the mandibular l incisors
* Measured using a ruler held parallel o the occlusal plane when teeth are in ICP and measurement taken from labial aspect of most prominent maxillary incisors to labial aspect of most prominent mandibular incisors
* Average- 2-4mm
* Classed as average, increased, decreased or reverse
57
Describe and give values for the following terms-
OB -
* Vertical relationship (degree of overlap) between the maxillary central incisors over the mandibular central incisors
* Measured using a ruler held perpendicular to the occlusal plane and measured relative to incisal edges
* Average- ½-1/3 coverage of lower crown
* Classed as average, increased or decreased, complete or incomplete
58
Describe and give values for the following terms-
Molar relationship
* Based on the buccal segment relationship of the teeth
* Class I- Mesiobuccal cusp of upper FPM occludes with the mesiobuccal groove of the lower FMP
* Class II- Mesiobuccal cusp of upper FPM occludes anterior to the mesiobuccal groove of the lower FMP
* Class III- Mesiobuccal cusp of the upper FPM occludes posterior to the mesiobuccal groove of the lower FPM
59
4. Describe Canine relationship-
* Class I- Mesial slope of upper permanent canine occludes in the embrasure between the lower canine and first premolar (distal slope of lower canine)
* Class II- Mesial slope of upper permanent canine occludes anterior to the embrasure between the lower canine and first premolar (distal slope of lower canine)
* Class III- Mesial slope of upper permanent canine occludes posterior to the embrasure between the lower canine and first premolar (distal slope of lower canine)
60
Describe crowding and how it is measured?
* Can be classified as uncrowded, mild (<4mm) , moderate (4-8mm) or severe (>8mm)
* Measured by the total measurement of overlap of all the teeth added together or the difference between the space available and the space needed for all the teeth (can also used mixed dentition analysis)
61
Incisor angulation
* Angle of the upper and lower incisors to the maxillary and mandibular planes respectively
* Averages- 109° for upper & 93° for lower
62
7. How is the anteroposterior skeletal relationship measured and give average values?
- Palpation of the skeletal bases
- Visual assessment
* Lateral cephalometry- average values- SNA- 81°, SNB- 78°, ANB- 3°
* Average values- Class I; maxilla 2-3mm anterior to mandible, Class II; maxilla >3mm anterior to mandible, Class III; mandible anterior to maxilla or maxilla <2mm in front of mandible
63
8. How is the vertical and skeletal relationship measures and give values?
* FMPA; Frankfort plane from lower border of orbit to external acoustic meatus and mandibular plane along lower border of mandible and on average planes meet at back of the head (27° +/- 4 on lateral cephalometry)
* If decreased- meet behind occiput (<23°) and if increased- meet before occiput (>31°)
* Anterior face height ratio- measure UAFH:LAFH (upper from glabella to subnasale and lower subnasale to menton); average ratio 50:50 (or 55:50 on lateral cephalometry)
* Both can be assessed visually or via lateral cephalometry
64
9. How is the transverse relationship assessed?
* Visually by assessing patient from front and from above using mid-sagittal line as a reference
65
Impacted Molars-
The mother brought her 7-year-old child with impacted first upper molars and crowded lateral incisors into the surgery.
1. List 5 possible treatment options for impacted molars? (5)
- Accept and monitor
- XLA of E to give molar space (retain space of pre-molar or tx crowding at later stage
- Place seperators to encourage disimpaction, dicing of E, URA with finger spring and attachment on 6, band E and bracket 6 with open coil
- Ortho appliance attached to 6 to bring it into position
- Surgical Ex
66
2. His mother mentions that his primary teeth were very straight but the permanent incisors are much wider than the primary incisors. What features of normal development should prevent crowding of the permanent dentition? (3)
- Growth of the mandible and maxilla
- Proclination of the permenant teeth creates space
- Nutural spacing of the primary teeth allows for relief of crowding in permenant dentition. This is known as the primate space
- Extension of dental arch
67
3. What is leeway space and how does this relieve crowding? (2)
Leeway space is the difference between C,D,E and 3,4,5
* Extra mesio-distal space/width occupied by the primary molars which are wider than the premolars and canine that will replace them allows space for both permanent molars and premolars
* Usually equates to 1.55 per side on upper and 2.5mm per side on lower
68
4. Why might a first molar be impacted?
- Small maxilla or mandible
- Eruption angle
- ectopic crypt
- Morphology of second primary crown
69
5. What are the possible deleterious effects of impacted teeth?
- Root resorption of adjacent teeth
- Associated with cyst formation
- For FPM - pulpitis of E or premature exfoliation of E
- Caries as difficult to clean
70
Hypodontia-
An 8-year-old child attends with hypodontia
1. Name two syndromes or conditions associated with missing teeth? (2)
- Down syndrome
- CLP
- Hurlers syndrome
- Ectodermal dysplasia
71
2. How may hypodontia present to you as a GDP?
- Delayed or asymmetic erruption pattern
- Infra-occluded primary teeth
- Missing primary teeth so spacing
- Patient with syndromes CLP
- Abnormal tooth formation
- Delayed exfoliation of deciduous teeth
- Might present on radiographs
- Microdontia assocaited with hypodontia
72
3. How can you diagnose hypodontia? (1)
OPT
in conjuction with clinical findings to comfirm that teeth are not present
73
4. Excluding 8’s, what three teeth in order are most commonly missing?
- Lower 5's
- upper 2's
- upper 5's
74
5. What is hypodontia?
The congential absense of one or more teeth excluding the third molars
Can be associated with microdontia and usually affect the lower 5's upper 2's an upper 5's
75
Early Tooth Loss-
1. What 4 factors make early loss of primary teeth worse?
-** Age** of the patient when the teeth are lost. The earlier they are lost the more space that is lost.
- **Inherent crowding** - if arch already crowded likely to be more severe space loss
- **Tooth position **in the arch - E is the most significant as ^ most likely to drift mesially into the space (generally more marker affect further back in the arch
**- Which arch **- more marked space loss in the maxilla
76
2. When might you considering balancing a primary tooth extraction?
- If a C needs to come out to prevent a centre line shift
77
3. Give 4 reasons for an unerupted central incisors?
- Supernumerary
- Crowding
- Truama to primary (displacement or dilaceration)
- Ectopic tooth
- Retained primary tooth (ankylosed
- Patholgy
- Developmentally absent
78
4. What are your treatment options for a unerupted central incisor?
- Accept
If present and depending on cause
- Removal of supernumerary if present +/- surgical exposure
- Closed exposure - expose tooth, bond gold chain and close flap
- Open exposure - apically repositioned flap used to expose tooth, orth appliance may be utilised to pull tooth down
- If tooth difficult to access (high up) may leave the tooth to erupt a little and then surgically expose when more accessibl e
- Before bringing tooth in place need to create space for it to erupt into - Fixed sectional appliance
79
5. What is a balancing extraction?
* Extraction of a tooth from the opposite side of the same arch
80
1. What is a supernumerary? (1)
* A tooth or tooth like entity which is additional to the normal series
* (1% in primary and 2% in permanent)
81
2. Where is a supernumerary most likely to occur? (1)
Anterior in the maxilla
82
Give the 4 type of supernumerary?
Conical - small conical peg shaped, 1 or 2 in number, usually close to the midline, tend not to prevent eruption of other teeth
Tuberculate - barrel shaped, usually paired, often prevent eruption of adjacent teeth and so require extraction
Supplemental - extra teeth of normal morphology, decision on which tooth is extracted determined by the form and positino
Odontome - compound (discrete denticles) and compound (irregular mass of dentine pulp and enamel) forms
83
Give 4 effects supernumeraries can have on the permenant dentition?
- Impaction or impeded eruption
- Cysts
- Displacement of teeth
- Root resorption
- Poor aesthetic
- Assocaited with the cause of diastemas
- Traumatic eruption
- occlusal interference
- Crowding
84
Crossbites & Mandibular Displacement-
Child present with disaplacement on closing on RHS with posterior unilateral crossbite of d,e, & 6 on RHS.
1. What does mandibular disapclement on closing mean?
Occurs where ther is an inter-arch discrepancy. Which causes upper and lower posterior teeth to meet cusp to cusp. as a result of this the mandible is forced to deviate to one side to achieve ICP
Often associated with TMD, parafunction and toothwear
85
2. What 2 problems may the patient suffer if disapclement is not treated (why treat)?
- TMD
- Parafunctional habit
- Toothwear
- facial asymetry which can be aesthetic issue
- teeth may erupt inot displaced ICP
86
3. Child present with disapclement on closing on RHS with posterior unilateral crossbite of d,e, & 6 on RHS.
Design a URA to treat this patient?
Please construct a URA to fixed a posterior crossbite
A - mid-palatal screw (1/2 turn a week)
R - Adams clasp on the 6's 0.7mm HSSW and D's 0.6HSSW
A - check
B - Self cure PMMA with flat posterior bite plane
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4. Why can you not use Southend clasp in this URA design?
Links the two side of the arch together and stops the midline palatal screw working
88
5. What other options are there for the correction of a unilateral posterior crossbite?
* Quad helix- allows differential expansion on each side of the mouth (need to take out of the mouth every time you want to reactive then replace it)
* Rapid maxillary expansion (only before fusion of the midline palatal suture at around age 16)
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URA-
1. Give 3 uses of a URA other than tipping and tilting of teeth?
Active and passive functions
- Expansion of the upper arch
- Reducing OB
- Reducing OJ
- Habit breaker
- Space maintainer
- retainer
90
Give 8 signs of good wear of the URA at the review appointment?
- Ask the patient if they have worn it
- Patient arrives wearing it
- Patient can easily take URA in and out
- Patient can speak with it in
- Looks worn
- Acitive component now sits passive (sits proud of the tooth) and
- Teeth have moved (1mm a month)
- Signs of wear on the palate of URA
- No excess salivation
- Clasps of the appliance loose
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Outline the steps in delivery of a URA?
- Check corret appliance for correct patient
- Check that it is the correct design and matches prescription
- Check for any sharp areas or wire sticking out of polishing and fitting surface of base plate that could cause trauma
- Check the integrity of the wire work for areas of damage or work hardening
- try in the patients mouth
- Check for any signs of blanching, damage or truama to the soft tissues
- Check the posterior retention
- Check for anterior retention
- Remove from patients mouth
- Activate the components as required
- Show the patient how to inser the appliance without causing damage
- Get patient to demonstrate
- give instructions
- Review 4-6 weeks
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4. What instructions/advice would you give to a patient on delivery of URA?
- Appliance may feel big and bulky - will get used to this
- may get increased salivation but this will pass in 24 hrs
- Warn them of altered speech but the soft tissues will adapt gradually
- May give mild discomfort and pressure
- Wear all the time 24/7 including mealtimes and only remove the device to clean after meal with soft brush No TP as abrasive and contact sports
- Avoid hard or sticky foods
- non compliance will delay tx
- Give emergency contact
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What are the 5 factors to resist displacment forces of URA?
- Tongue
- Gravity
- Speech
- Mastication
- Active component
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6. Design a URA to reduce an 8mm overjet and overbite, 1st premolars have been extracted but anterior crowding still present?
* Please construct a URA to retract 13 & 23 and reduce overbite
* A- 13 & 23 palatal finger spring 0.5 HSSW w/ 0.5mm HSSW guard
* R- 16 & 26 Adam’s clasps 0.7mm HSSW & 11 & 21 Southend clasp 0.7 HSSW
* A- Check
* B- Self cure PMMA with 11mm FABP (8mm OJ + 3mm)
95
7. Design a URA to reduce a 6mm OJ, 1st premolars have been extracted an a previous URA retracted canine and reduced overbite? (Follow up appliance from question 8 but different OJ)
* Please construct a URA to reduce a 6mm overjet and continue to reduce overbite
* A- 12,11,21,22 Robert’s retractor 0.5mm HSSW with 0.5mm ID tubing, 13 & 23 mesial stops
* R- 16 & 26 Adam’s clasp 0.7mm HSSW
* A- Check
* D- Self cure PMMS acrylic with 9mm FABP (6mm OJ + 3mm)
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Complications & Retainers-
A patient has a 12mm overjet and ectopic canines.
1. What are the dental complications of this?
- Increased risk of trauma
- Poor aesthetics
- Difficulty with speech and mastication
- Dry mouth
- Displacement on opening
- Ectopic canines may resorb adjacent teeth
97
2. What are the complications of a bonded retainer?
- Act as a plaque trap need good OH
- May fracture, high failure rate
- May debond without patient knowing and teeth move
- may cause trauma or wear to opposing teeth
98
3. What are the advantages and disadvantages of different types of retainers?
* Removable Thermoplastic Retainer- aesthetically pleasing, no palatal or lingual impingement, no tooth preparation required, can be removed for cleaning, coveralls all teeth, not very strong and becomes brittle over time, can become trap for sugary food and drinks if poor diet, easily lost, deforms on cleaning with hot water, abraded by toothpaste (looks opaque over time, may try use if for whitening, replies on patient compliance with wear, can wear down in those with parafunctional habits, doesn’t allow occlusal settling
* Fixed Bonded Retainer- Fixed & so there 14/7, good aesthetics, small and unobstructive, allows occlusal settling, only incorporates anterior teeth (posterior relapse potential), OH issues, tooth preparation requires, high failure rate and potential for debonding
- Hawley retainer. Strongest, can be removed for cleaning, retains all teeth, no occlusal coverage so allows occlusal setting, no tooth preperation, can induce small amount of force (and so correct small amount of relapse, poor aesthetics, big and bulky (speech and salivation).. poor compliance due to aesthetics, lingual impingement so lower not well tolerated. Expensive
99
Class 2 Div 1-
1. What is the BSI definition for incisor classification Class 2 Div 1?
* Lower incisor edges occlude posterior to the cingulum plateau of the upper incisors
* Upper incisors are proclined or average inclination
* Overjet is increased
100
2. What are the dental features in class 2 div 1 patients?
- Increased OJ
- Proclined ULS and retroclined LLS
- OB variable
- not always but class 2 buccal and canine segments
101
3. What soft tissue problems are associated with class 2 div 1 malocclusions?
- Incompetent lips (may lead to drying of gingivae and exacerbation of any pre-exisiting gingivitis)
- Inability to achieve an oral seal
- May have a lip trap or tongue thrust
102
4. What are the treatment options? For class ll div 1 with 12mm OJ?
* Accept and monitor- mild OJ with no significant patient concerns (small trauma risk)
* Attempt growth modification- using twin block, Frankel II, or headgear
* Fixed appliance- to allow camouflage (accept underlying jaw relationship and correct incisors to class I)
* Orthognathic surgery- when growth is complete and there is a several AP or vertical skeletal discrepancy
* URA- limited use as unfavourable type of tooth movement but can use Robert’s retractor
103
5. What are the 6 features of a twin block appliance?
- 2 seperate bite blocks
- Can have a midline expansion screw to allow for expansion of the maxilla
- Anterior labial bow to push the upper anterior teeth back
- Adams clasps on teeth
- postures patient edge to edge
- Removable functional appliance worn for 9-18months
- Detergent rake can be added to prevent a non-nutritive sucking habit
104
6. What makes a class II div 1 malocclusion amendable to correction via removable appliance therapy (URA)-
Very mild class ll
Oj almost entirely due to incisor proclination
Favourable OB to prevent relapse
Only ise after specialist assessment
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Class II Div 2 Occlusion-
1. What is the definition of class 2 div 2?
- The lower incisor edge lie posterior to the cingulum plateau of the upper incisors
- The upper incisiors are retroclined
- THe OJ is reduced (minimal) or may be increased
106
What dental features are seen on a class ll div 2?
- Upper and lower incisors are retroclined (Increased interincisal angle)
-Increaed overbite (lower incisors occlude with upper or on palate)
- Usually class ll canines and molars
- OJ usually reduced but may be increased
- Upper 2's often crowded - may be normal, proclined or mesiolabially rotated depending on their position relative to the lip line
- Reduced arch length and crowding
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3. What soft tissue features may be seen? in a class ll div 2?
- Lip Trap
- Trauma to gingivae or palate
- High bite force
- High resting lower lip line (lateral may escape effect of this resulting proclination or M-Lateral rotation of them)
- Accentuated labio-nasal fold
108
4. What are the treatment options? for class ll div 2.
- Accept and monitor (acceptable aesthetics, patient no concerned, OB not a significant problem)
- Attempt growth modifcation - modified twin block (or upper sectional fixed appliance)
- FA and or URA for camouflage tx 0 accept underlying skeletal base and aim to treat the class 2 incisor relationship to make it class 1
- Orthognathic surgery
109
Class lll Occlusion-
A 10-year-old patient in the orthodontic department present with a class III incisor relationship.
1. What is BSI classification of class III incisors?
* Lower incisor edges occlude anterior to the cingulum plateau of the upper central incisors
* The overjet is reduced or reversed
110
2. What is dentoalveolar compensation?
The process by which the body and dentoalveolar structure work to try and disguise the underlying skeletal discrepancies and ensure the maintenance of the occlusion between the upper and lower arches (maintain normal inter arch relationship) despite variation in the facial pattern and growth. It most commonly takes the form of the soft tissues (of the lips, cheeks and tongue) inclining to the incisor teeth towards each other to a position of soft tissue balance
111
Name 4 specail investigation you would carry out for A 10-year-old patient in the orthodontic department present with a class III incisor relationship.
- Radiograph OPT
- later ceph
- Study models
- Clinical photographs
- Sensibility testing
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What other dental features may be associated with A 10-year-old patient in the orthodontic department present with a class III incisor relationship.
- Reduced OB and possible AOB
- Reversed OJ
- Anterior and posterior crossbites
- Maxillary crowding
- Tendancy for displacement on closing
- Dentoalveolar compensation Proclined uppers and retroclined lowers
- Class 3 canine and molar relationship
113
What tx is available for A 10-year-old patient in the orthodontic department present with a class III incisor relationship.
- Accept and monitor (if mild class lll or unsure how growth and development will progress)
- Growth modification with reversed twin block or frankel lll, Head gear with RME or TADs
- FA +/- Ex for ortho camoflague (accept the underlying skeletal base and correct incisors) N.B patient needs to reach edge to edge.
- Orthognathic surgery combined with FA
114
Ectopic Canines-
Child Attends with an ectopic canine.
1. At what age should you be able to palpate the canines in the buccal sulcus?
Palpate the canines from 9 onwards
9-11
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2. What method you use to localise the position of the canine?
* Radiographical parallax technique using two views with a tub shift- using vertical parallel from OPT and upper anterior occlusal or horizontal parallax using 2x PA
* Tells you 3Ps’- presence, position and pathology
116
3. What age range is ideal for interceptive orthodontics?
10-13 due to puberty and the growth spurt
117
4. How long after extraction of C’s should you review ectopic canines?
12 months
118
5. What are the treatment options after extraction of retained C?
- Monitor and seee if canine spawntaneously erupts on its own
- Closed exposure (raise a flap, remove bone covering and attach gold chain to ectopic tooth, replace flap and wait for the tooth to erupt into line)
- Open exposure (Raise flap, remove bone and expose tooth, reposition flap apically (if buccally) and either wait for tooth to move down or attach ortho appliance to help pull down.
- Transposition
- Surgical Ex of canine
119
Child attends with ectopic canines?
1. At what age should you palpate for canines?
9
120
2. What clinical sings indicate impacted canines?
- Retianed C's (delayed exfoliation)
- Tipping distally of laterals
- Delayed eruption of canines
- Asymmetrical eruption
- Loss of vitality, discolouration of the lateral
- No palpable canine
- Missing or peg laterals
- Roots visible through labial gingivae with no palpable bulge of canine above
121
How can you investigate a ectopic canine?
Radiographs (parallax)
OPT, standard occlusal
2 PA's
CBCT
122
4. What are the risks of impacted canines?
- Cystic changes
- Root resorption of adjacent teeth
- Retianed C
- Aesthetic issue of missing teeth and spacing
123
What are the tx options for a ectopic canine?
Monitor
Extract C's age 10-13
Let is spawntaneously erupt in mild cases.
Otherwise
- Closed exposure (gold chain and FA)
- open exposure ( if buccal need to apically repositioned flap)
- FA to apply traction and align
- Transposition of canine
- Ex canine and deal with space with prothesis
124
URA Components-
1. Name 5 active components, their measurements and uses?
* All 0.5mm HSSW
* Palatal finger spring- 0.5mm HSSW with guard- retract teeth
* Buccal canine retractor- 0.5mm HSSW with 0.5mm tubing- retract buccal placed canines
* Z- spring- 0.5mm HSSW- push/tip tooth labially, used in anterior cross bite
* Mid palatal screw- expand upper arch
* Robert’s retractor- 0.5mm HSSW with 0.55mm tubing- push/tip teeth labially, used to deuce overjet
125
2. Give 2 retentive components, their measurements
* 0.7mm HSSW on permanent teeth
* 0.6mm HSSW on primary teeth
* Adam’s clasp
* Southend clasp
126
3. Give two baseplate modifications and what they are used for?
* Flat anterior bite plane- allows eruption of posterior to aid anterior tooth movement- OJ + 3mm
* Flat posterior bite plane- allows disocclusion
