Orthodontics Flashcards
1
Q
What are fixed appliances?
A
-Brackets/bonds attached to teeth
- Mainly used in permanent dentition but can be used in interceptive treatment in the mixed dentition (sectional appliances).
- Control of the teeth in 3 planes of space
- Are more anchorage demanding.
2
Q
What are the 3 different dimensions of tooth movement?
A
- Tipping
- Bodily Movement
- Torque
3
Q
What are 5 indications for fixed appliances?
A
- Multiple tooth movements needed
- Rotations
- Bodily Movement
- Space closure (extractions or hypodontia)
- Lower arch treatment
4
Q
Name 4 contra-indications for placing fixed appliances.
A
- Poor oral hygiene
- Active caries
- Poor motivation
- Poor dietary control - hard/sticky foods, restrict sugars and acids.
5
Q
List the risks you should inform the patient of when placing fixed appliances.
A
- Root resorption
- Decalcification
- Loss of periodontal support
- TMJ problems
- Failed treatment and relapse
- Reversible risks: pain, ulceration etc
6
Q
What teeth would you place bands on with fixed appliances?
A
Usually on molars/premolars with ceramic crowns.
7
Q
What is straight wire brackets?
A
- Standard edgewire brackets require arch wire bends to produce ideal “tip”- Straight wire pore adjusted brackets have slot cut diagonally across face to build in ideal tooth position
- Without offset bends standard edgewise brackets do not align contact points labiolingually - however the variation in thickness of straight wire bracket bases aligns contact points labio-lingually
- Straight wire bracket slot cut at an angle to base to provide torque control.
8
Q
What are the 3 phases to active treatment?
A
- Levelling and aligning
- Major tooth movement- correction of overjet and overbite, space closure, centre line correction
- Finishing- detailed alignment
9
Q
Describe what happens in the levelling and aligning phase.
A
- Light flexible arch wires
- Usually arch wires changed each visit
- Wires on increasing stiffness
- Deformation energy dissipates as wires straighten and pull teeth into alignment
- Each new wire is deformed less but has higher deformation energy.
10
Q
What properties do NiTi wires have?
A
- High flexibility
- Deliver a low force over a long range
- Shape memory
11
Q
Describe what happens in the major tooth movement phase.
A
- Usually rigid wires
- Usually left unchanged each visit
- “Sliding mechanisms” - teeth push or pulled along the arch wire by power chain, by coil springs or by elastic bands.
12
Q
What properties do stainless steel wires have?
A
- Alloy of chromium, iron and nickel.
- Stiff and resist deformation
- Supports teeth as they move along the wire while closing space
13
Q
Describe what happens in the “finishing stage” of fixed appliances.
A
- Usually lighter wires than major tooth movement stage- allows occlusal settling
- Detailing of alignment and interdigitation - fine adjustments to bracket position, bends to arch wire, elastics.
14
Q
What advice would you give to your patient getting fixed appliances if they ask “will it be painful?”
A
It is likely to be painful for 3-5 days each time the brace is adjusted. If necessary pain killers that you would normally take for a headache may help (read instructions on the packet). If the brace rubs your lips or cheeks we will give you wax and instructions on how to place this over your brace.
15
Q
What advice would you give to your patient getting fixed appliances if they ask “can i eat normally?”
A
Yes you should be able to eat normally. However, for your orthodontic treatment to work well and in the shortest possible time, it is important to take care of your teeth and brace. In order to prevent damage to both you should:
- Avoid eating toffees, boiled sweets, chewing gum, chocolate bars etc
- Avoid drinking fizzy drinks
- Be careful eating hard foods such as crusty bread and crunchy apples.
16
Q
What advice would you give to your patient getting fixed appliances if they ask “what about tooth brushing?”
A
It is important to brush your teeth well, three times per day using fluoride toothpaste - a daily fluoride mouthwash should also be used.
17
Q
What advice would you give to your patient getting fixed appliances if they ask “how often will i need an apppointment?”
A
You will need regular appointments every 1-2 months during treatment for the brace to be adjusted.
18
Q
What advice would you give to your patient getting fixed appliances if they ask “do i need to see my regular dentist?”
A
Yes, it will be important you still have check ups with your regular dentist throughout orthodontic treatment so your teeth can be checked for decay.
19
Q
What do you the GDC expect GDP’s to manage with regards to orthodontics?
A
- “Recognise and explain to patients the range of contemporary orthodontic treatment options , their impacts, outcomes, limitations and risks.”
2.”Undertake limited orthodontic appliance to emergency procedures.”
20
Q
What can the GDP be expected be to if a patient attends the practice with a broken bracket?
A
Remove and make safe.
21
Q
What can the GDP be expected be to if a patient attends the practice with a lost module?
A
Replace if available
22
Q
What can the GDP be expected be to if a patient attends the practice with a protruding arch wire?
A
- Brace wax
- Cut short if possible
23
Q
What can the GDP be expected be to if a patient attends the practice with a protruding ligature wire?
A
- Brace wax
- Tuck in if possible
24
Q
List the instruments you would see in an archwire change kit
A
- ligature holders
- ligature cutters
- distal end cutters
- loop forming pliers
- weingart pliers
- mosquito forceps
- ligature tucker
25
What are removable appliances?
- Appliances fabricated mainly in acrylic and archwire.
- Removable appliances that are not permanently attached to the teeth.
- Can be removed and re-inserted into the patient
- Often used as an adjunct to a fixed appliance.
26
What are the different components of a removable appliance?
- Retention (clasps/labial bow)
- Active components
- Anchorage
- Base plate modifications
27
Name some types of clasps that are provided for retention on a URA?
- Adams clasps
- Delta clasps
28
Name active components that are on a URA.
- Palatal finger springs
- Z spring
- T spring
- Roberts retractor or beam spring
- Orthodontic screws
- bows
- biteplanes?
29
Name 5 types of removable appliances.
1. Retainer
2. Active plate
3. Pre-surgical orthopaedics
4. Space maintainer
5. Interceptive appliance
6. Functional appliances
30
List the advantages for using a removable appliance.
- Can be removed for OH and sports
- Increased anchorage
- Easy to adjust
- Less iatrogenic damage
- Baseplate can be modified
- Good at moving blocks of teeth
- Can be passive
- Lower cost.
31
What are the disadvantages of a removable appliance?
- Need good patient compliance
- Limited movements- tipping
- Affects speech
- Technician required
- Lower appliances difficult to tolerate
- Inefficient at multiple tooth movements
32
What are the active components of springs made of, what are the dimensions they are constructed in?
- 18/8 austenitis stainless steel
- Constructed in 0.5mm or 0.7mm stainless steel wire to move a single tooth or groups of teeth
- The more wire incorporated, the greater the range of the spring, and the lighter the force exerted
33
What does the equation F= d.r4/l3 mean?
F= force
D= deflection
L= length of the spring
R= radius of the wire
Therefore increasing the radius by 2 will result in a force applied increasing 16 times.
34
What is the maximum force that should be placed for a single tooth movement?
25-40 grams
35
Where is the force applied in springs to reduce the tipping tendency?
Close to the gingival margin.
36
Name 4 examples of springs.
1. Z spring
2. T spring
3. Palatal finger springs
4. Buccal canine springs
37
Describe what screws are in a URA.
- Can be embedded into base plate
- Activated by patient turning a key
- Expansion or distalisation
- Each quarter turn of the screw = 0.25mm separation
- Bulky
- More expensive
- Teeth being moved can be clasped
- Can expand x2 or x3
38
Name 4 types of clasps/cribs that can be used for retention on a functional appliance and what teeth they are most likely to be placed on.
- Adams cribs (mainly used on molars and premolars but can be incisors and canines)
- Delta cribs - same as adams.
- Southend clasps- mainly used for incisors
- Ball hooks - interdental embrasure
39
What are the dimensions used for adams/delta cribs?
- molar clasps 0.7mm stainless steel round wire
- Premolar/deciduous clasp 0.6mm wire
40
What are the dimensions used for southend clasps?
0.6 or 0.7mm wire
41
What are the dimensions used for ball hooks?
0.7mm wire with soldered ball on end
42
Are clasps/cribs less or more effective on deciduous teeth?
less effective as less undercut.
43
Where should adams clasps/cribs engage on the tooth?
- mesial and distal corners of the edges.
- should engage 1mm of the undercut
44
What are adams cribs adjusted with?
Adams pliers
45
What is Newtons 3rd law that applies to anchorage in removable appliances?
"For every action there is an equal and opposite reaction".
46
Name 5 ways we can reinforce anchorage with URA's.
1. Headgear
2. Clasp more teeth
3. Use lighter forces
4. Occlusal capping
5. Move only one or two teeth at a time
47
Describe the base plate in a removable appliance.
- Connect to components of the appliance
- Made of acrylic
- Supports anchorage through palatal coverage
- Active or passive baseplate
- Anterior- bite plane- usually flat FABP
- Buccal capping
48
What information should you give to the lab when prescribing for a removable appliance.
First of all ensure you have a good impression
- Tell them what the appliance is for
- Retention components
- Active components
- Baseplate modifications
- Patient details: use patient sticker
- Draw the design on lab slip
- When is it required- check this can be done for then
49
What actions/checks would you carry out when fitting a removable appliance on a patient?
- Check that the appliance is the correct one for the patient
- Check acrylic for sharp edges esp in palatal rugae area
- Fit appliance in patients mouth. Note any rocking or areas that do not fit and adjust if necessary
- Tighten clasps and check retention
- Activate springs and check that teeth are free to move
- Chat to the patient with the appliance in place- ask about any discomfort
- Give written and verbal instructions to patient and parent. Normally removable appliances are worn 24 hours per day. Warn of initial discomfort/lisping etc
- Book review appointment
50
How long does treatment with a removable appliance usually take?
6-12 months but may need a fixed brace for a further 12 months to complete treatment. Varies according how severe cases are.
51
What actions/checks should you carry out at the review appointment?
- Chat to patient and note speech with appliance in place. Ask about any problems
- Check appliance out of mouth. Note loss of surface lustre, tooth impressions on bite planes etc.
- Check condition of mouth - palatal mucosa should have indentation or redness if good URA wear. Note any trauma from springs etc
- Check position of teeth that are being moved and the anchor teeth from the original study models.
- Teeth should be slightly mobile if movement is occuring. If teeth are not moving, look for a cause (acrylic in the way, insufficient activation of springs, unerupted teeth, retained roots etc).
- Reactivate springs 1-2mm and tighten cribs. Show patient how to turn the key for the screw.
- Congratulate patient if appropriate and reappoint
52
Approximately how much tooth movement should occur per month with a removable appliance?
1mm
53
Describe what clear aligners are.
- Clear, removable plastic appliances which can produce small tooth movements
- Treatment involves a series of aligners
- Tooth movement is achieved by deformation of the aligner
- Composite attachments are often bonded to the teeth
- Good case selection if required
54
Describe the different stages in planning and fitting clear aligners for patients.
1. Standard records- photos/radiographs/impressions/IO scan
2. Clinician sends a prescription - treatment aims - what is to be corrected or accepted
3. Virtual set-up sent to orthodontist by a technician
4. Clinicians responsibility to authorise the treatment plan
5. May require elastics, attachments, IPR
6. 22 hours to wear a day
7. Advice on when to change aligners
8. Retainers
55
Who can provide treatment for clear aligners?
Specialists and dentist who have sought appropriate training and are competent to provide the treatment to a satisfactory standard.
56
What kind of design would you provide for a removable appliance for where a patient's upper incisor is behind the bite.
Retention: Adams cribs upper 6's and upper 4's
Active component: Z spring to upper incisor affected
Bite opening: Posterior bite capping to allow space for the 1 to move forward and make it more comfortable for patient
Base plate: to connect everything together, also some anchorage.
*Activate Z spring by pushing spring up onto tooth.*
57
What kind of design would you provide for a removable appliance for where a patient has a reverse overbite (all 4 incisors behind bite).
Retention: Adams cribs upper 6's and upper 4's. Anterior retention with a southend clasp upper 1's
Active component: Expansion screw to section upper 2-2
Bite opening: Occlusal capping posteriorly to allow space to push teeth forward
Screw is opened up one quarter turn twice a week and pushes upper incisors forward over the bite
Base plate: To connect everything together, also some anchorage.
58
What kind of design would you provide for a removable appliance for where a patient has an increased overjet with proclined incisors.
- Extract upper 4's to allow overjet reduction
1st Stage:
Retention: Adams cribs on upper 6's and Southend clasps upper 1's
Active components: Palatal finger springs upper 3's with wire guards for stability
Bite opening: Flat anterior bite plane (FABP)
* This will retract the canines back into the space where 4's were however 2-2 still need to be pushed back*.
2nd stage:
Retention: Adams cribs upper 6's and 5's. Mesial stops upper 3's to prevent canines going back forward.
Active Component: Labial bow in 0.7mm wire with large U-loops to allow activation.
Bite opening: Flat anterior bite plane (FABP)
Labial bow activated 1-2mm each visit by squeezing vertical legs of U loops together. Palatal acrylic must be trimmed away by the same amount
59
Why is the positioning of the palatal finger springs when pulling canines into the space where 4s have been extracted so important?
Spring too far anteriorly: tooth will move palatally
Spring too far distally: tooth will move buccally
60
Why is it necessary to reduce the overbite before the overjet?
As incisors tip, the lower incisors prevent further overjet reduction due to increasing overbite. This can be done with an anterior bite plane.
61
What kind of design would you provide for a removable appliance for where a patient's UL5 has deflected palatally and the UR6 has drifted mesially.
Retention: Adams cribs upper 6's and southend clasps upper 1's
Active component: Screw to section UR6, Z spring to UL5
Base plate
62
What kind of design would you provide for a removable appliance for where a patient's UL3 is placed buccally.
Retention: Adams cribs upper 6's and upper 4's
Anchorage reinforcement; Headgear attached to upper 6s
Active Component: Screw section to distalise UL456
63
What kind of design would you provide for a removable appliance for where a patient has Class II div I and upper 6's are carious
1. Extract 6's
2. Adams cribs on upper 7's and upper 3's, finger springs on upper 5's and upper 4's, fitted labial bow upper 2-2
3. Retract upper 5's back into space
4. Retract upper 4's back into space
5. Place Adams cribs on upper 7's and upper 4's and retract 3's back with finger springs upper 3's and place a southend clasp upper 1's.
6. URA with labial bow to retract upper 2-2 back into space.
64
What kind of design would you provide for a removable appliance for where a patient has an unerupted LR5 where extraction of the LR4 would give too much space
Retention: adams cribs lower 6's and 4's. Southend clasp lower 1's
Active component: Screw placed to push LR6/7 distally.
Base plate made.
65
What are the 2 types of bone formation/ossification in the face
1. Intra-membranous
2. Endo-chondral
66
What is intramembranous ossification?
Mesenchymal cells differentiate into osteoblasts, calcification occurs turning it into bone. The mandible and maxilla bone occur like this.
67
What is endochondral ossification?
Cartilage cells undergo hypertrophy which changes into a calcified matrix, osteogenic invasion occurs which changes into bone. Condylar cartilage and nasal septal cartilage occur like this.
68
At what age does the maxilla stop growing?
12 years old
69
What age does the mandible start and stop growing?
Starts age of 10 and stops around 14-16 years old.
70
Describe the different phases of growth of the mandible.
Area of condensing bone above ventral part of developing mandible.
Develops in cone shaped cartilage
Migrates inferior and fuses with mandibular ramus
Cone shaped cartilage replaced by bone but upper end persists acting as growth cartilage.
71
What type of bone ossification occurs in the mandible?
BOTH endochondral and mesenchymal ossification
72
Does ossification extend at the front or the back of the mandible?
Back.
73
Describe the remodelling process of the development of the maxilla.
A process which involves deposition and resorption occurring on opposite ends.
- progressively change the size of the whole bone
- Sequentially relocate each component of the whole bone
74
Name some of the naso-maxillary complex sutures.
- zygomatico-frontal
- fronto-maxillary
-naso-maxillary
-zygomatico maxillary
- zygomatico temporal
- palato-maxillary
75
Growth spurt is important in ortho. If considering using a growth appliance when is it a good time to use this?
Just before puberty between ages 11-14
76
What are the problems with class 2 maxillary excess?
Lowering or the palatal plane, supra-eruption of the dentition and teeth and gums visible.
77
What is the typical treatment for class 2 maxillary excess?
Can use headgear for this. Orthopedic and functional appliances together both contribute to bone growth. Preventing the maxilla from going any further forwards allows the mandible to catch up. Used for around 8 months, wear for around 12-15 hours a day and the best time to wear it in the evening and at night.
78
What is the problems with Class 3 maxillary deficiency?
Reduced lowering of the palatal plane, overclosing of the mandible
79
What is the treatment for class 3 maxillary deficiency with functional appliances?
Face mask used to treat. Pushes the maxilla downwards and forwards. Also pushes the mandible downwards and backwards. Wear this 12-15 hour at night and evening. Patient must turn expansion screw every week in palatal appliance to open up sutures around the maxilla. This is also known as reversible head gear as well as a face mask.
80
Give a definition of a functional appliance.
An appliance that utilises or redirects the forces of the masticatory and/or the circum-oral muscles to produce or permit tooth movement and may modify facial growth.
81
Name 5 types of functional appliances.
- Andreson
- Twin block
- Frankel
- Bass
- Herbst
82
How does functional appliances work?
stretch the muscles of mastication
posture mandible
differential tooth eruption
83
What skeletal effects would a functional appliance do for Class 2 div 1 patient?
- Causes forward displacement of the mandible
- Places a backwards force on the maxillary arch
- Accelerates condylar growth
- Redirects condylar growth.
84
What dentoalveolar effects would a functional appliance do for Class 2 div 1 patient?
- Retracts upper teeth
- Proclines lower teeth
- Different rates of tooth eruption
85
Functional appliances cause what % skeletal movement and what % dental movement
Functional appliances cause 60% skeletal movement and 40% dental movement
86
What did the North Carolina Study conclude about Class 2 div 1 patients with functional appliances.
- Functional appliances produce slightly more mandibular growth.
- Functional appliances reduce the need for orthognathic surgery
- Headgear reduces maxillary growth
- Shorter time with fixed, but overall longer treatment.
87
What did the Manchester RCT O Brien et al study conclude about functional appliances
- Functional appliances produces slightly more mandibular growth
- Early treatment improves self image
- Twin blocks as effective as Herbst appliances
88
What is the mean value for SNA in lateral cephs
81 +/- 3
89
What is the mean value for SNB in lateral cephs
78 +/- 3
90
What is the mean value for ANB in lateral cephs
3 +/- 2
91
What is the mean value for MMPA in lateral cephs
27 +/- 4
92
Are functional appliances really effective?
Best chance of success would be to limit functional appliance treatment to patients who present with the following parameters:
- mild to moderate increase in overjet up to 11mm
- Increase in overbite
- Active facial growth
- Willingness to comply
93
Name 6 indications for functional appliances.
1. Motivated patient
2. Pre-adolescent growth phase
3. Skeletal discrepancy mild or moderate
4. Increased overjet/overbite if Class 2
5. Proclined maxillary incisors (if Class 3)
6. Well aligned arch
94
Name 5 contra-indications of functional appliances
1. Poor motivation
2. Age >14
3. Poor dental health
4. Condylar disease e.g juvenile rheumatoid arthritis
5. Proclined lower incisors
95
State advantages of using a functional appliance
Removable (easy to clean)
May avoid extractions: if good response to treatment
Accelerates skeletal growth
Reduces incidence of trauma
Early treatment
Economical
Less damage to tooth tissue (less root resorption, decalcification, effect on bone levels).
96
What are disadvantages of using a functional appliance?
- Compliance (bulky, speech, soft tissue trauma)
- Lack of detailed tooth movements
- Candidiosis with removable appliances, use of inhalers
97
What would you do for a patient needing a functional appliance but also had crowding in their arches?
Functional appliance then fixed
Cases where skeletal class 2 with well aligned arch--> just functional appliance.
98
What types of information do you need to treatment plan for an orthodontic case?
- Full diagnostic records: history and examination, study models, photographs, radiographs.
99
What are the different considerations/steps you should take into account when treatment planning?
1. Does the patient need the treatment
2. Does the patient want the treatment? - motivation and cooperation
3. Is now the right time? Growth, dental stage
4. What type of treatment? Visualise tooth movement required- space analysis, Appliance type
100
What are 5 ways to create space to allow tooth movement?
1. XLA
2. Enamel stripping
3. Distalisation
4. Proclination of incisors
5. Arch expansion
101
Name 7 things you would look for in a radiograph before starting orthodontic treatment.
1. Teeth present
2. Teeth missing
3. Caries
4. PA pathology
5. Crown: Root ratio
6. Condyles - symmetrical
7. Bone levels
102
Would extractions be needed if 0-4mm space was required?
No
103
Would extractions be needed if 4-8mm space was required?
Borderline
104
Would extractions be needed if 8+mm required?
Yes
105
What factors would contribute in the decision if extractions were required for a 4-8mm space requirement?
- Profile
- Skeletal pattern (antero-postero and vertical)
- Class II div II/deep bite/retroclined incisors
- MH
106
Why are premolars often the choice of teeth to extract?
- No aesthetic impact on smile
- Space near to crowding
- Straightforward extraction usually
- Molars provide good anchorage for appliances
107
Why are first permanent molars seldom the first choice to extract?
- Big tooth to extract, but provides little space anteriorly
- Long treatment
- When of poor quality can be extracted eg caries or large restorations
108
When is a lower incisor useful to extract?
- Class 3 malocclusion
- Lower incisor crowding only problem - adults
- Severe rotation
- Severe displacement
109
When can an upper lateral incisor be useful to extract?
- Very palatally displaced
- Trauma
- Contralateral tooth congenital absent/peg
- Canine good shape/size/colour
110
When would it be useful to extract upper canines?
- Ectopic (palatal, buccal, and upper 4 in good position)
111
When would you extract upper central incisors?
Never the ideal tooth to extract but:
- trauma
- dilaceration
- ectopic
112
When would you extract a lower canine?
Never tooth of choice because poor contact 2-4 leads to long term perio problems
Only if severely ectopic
113
When would you extract second permanent molars?
- Only provides very little space to relieve crowding
- Can help with moving upper posterior teeth distally
- May dis-impact third molar
114
When would you extract third molars for ortho treatment?
No evidence that removal of lower third molars prevent lower incisal crowding.
115
What are tooth factors you would take into consideration when planning extractions?
- Tooth quality e.g hypoplastic teeth
- Pathology eg caries, pulp pathology, perio disease
- Congenitally absent teeth
- Abnormal tooth shape: crown/root dilaceration
- Difficult extractions e.g root morphology, unerupted teeth
116
Name 3 different types of retainers.
1. Vacuum/pressure formed retainers
2. Hawley retainers
3. Bonded retainers
117
What is the role of GDP in orthodontic cases in practice.
- Identify- Examination/Refer IOTN
- Maintain oral hygiene
- Orthodontic first aid
- Retention
118
What is the information to include in the referral letter.
- the urgency of the referral
- the suitability for the patient for ortho treatment
- patients full details
- Reason for referral and what complaint is
- MH
- Do they attend routine check up
- Oral hygiene standard
- Previous dental treatment
- Trauma
- SH
- Motivation
- Specific details about malocclusion
-IOTN
119
What is the definition of mixed dentition?
Period from eruption of the first permanent molar until the shedding of the last deciduous tooth
120
What age does the first permanent molar erupt?
6 years old
121
State the sequence of the eruption of adult teeth in the mandibular arch.
6's, 1's, 2's, 3's, 4's, 5's, 7's, 8's
Lower teeth erupt before the upper teeth except 5's
122
State the sequence of the eruption of adult teeth in the maxillary arch.
6's, 1's, 2's, 4's, 5's, 3's, 7's, 8's.
123
Name 4 abnormalities in tooth formation.
1. Crown root dilaceration
2. Supernumeraries
3. Peg shaped incisors
4. Hypodontia
124
What is usually the cause of crown root dilaceration?
Trauma in deciduous teeth.
125
Give a definition of supernumeraries.
- Additional teeth (can be exact copies of adjacent teeth e.g supplemental teeth) OR
- Contain tooth material but dont look like teeth - conical or tuberculate supernumeraries
126
Where do supernumeraries most commonly occur in the jaws?
- Premaxilla
127
What are supernumeraries called that occur in the midline of maxilla?
Mesiodens
128
What is the usual treatment for supernumeraries?
- some erupt, usually impede eruption of permanent teeth
- usually extracted if surgically removed
129
What is peg shaped incisors?
- Unknown aetiology
- Commonly affects lateral incisors
- Cause spacing and problems with aesthetics
- May be associated with absent contralateral incisor (hypodontia)
- Increased risk of ectopic canines
130
What is hypodontia and what teeth are most commonly affected?
- congenital absence of one or more teeth
- Can be hereditary
- Most commonly affects upper 2's and lower 5's
- Spacing and aesthetics biggest problem
- More common in the permanent dentition
- Present with delayed exfoliation of deciduous teeth or delayed eruption of permanent teeth
- Radiograph confirms diagnosis
131
Name 5 abnormalities in eruption and exfoliation.
- Eruption cyst
- Impacted teeth (deciduous and permanent)
- Infra-occluded deciduous teeth
- Retained deciduous teeth
- Cross bites in the mixed dentition
132
What is an eruption cyst?
- Appear as blue mucosa overlying an unerupted tooth
- Most common over E's and 6's
- Asymptomatic
- Resolve as tooth erupts
133
What is impacted teeth?
- Deciduous or permanent teeth that fail to erupt fully
- Can be partly erupted
- Usually due to: an obstruction (supernumerary), primary failure of eruption, insufficient space, ectopic teeth
134
What is the incidence of ectopic canines?
- Family history
- Females>males
- Class II div II
- Hypodontia/microdontia
135
What are the risks of impacted/ectopic canines?
- Cystic change
- Root resorption
136
How would you assess the eruption of canines?
- Assess position of upper 3's from 10 years onwards
- Should palpate by 11 years
- Should have mobile C's / symmetry
- If not investigate
137
What is infra occluded and retained deciduous teeth ?
- Often incorrectly called submerging
- Usually due to ankylosis - adjacent teeth erupt and ankylosed teeth remain unchanged vertically- gives appearance of submerging.
- Due to no permanent successor- idiopathic
138
What is the normal treatment for retained deciduous teeth?
- Usually require extraction if due to ankylosis - can deflect permanent successor
- Leave in situ if missing permanent successor
139
What are 3 reasons for premature loss of deciduous teeth?
1. Caries
2. Balancing and compensating extractions
3. Trauma
140
What can removal of teeth due to caries cause?
mesial drifting of 6's result in premolar crowding
141
What effects dentally can occur due to trauma of the deciduous teeth?
- Avulsion of deciduous incisors can result in a centre line shift in incisors
- Can experience delayed eruption of permanent successor - fibrous mucosa
- Intrusion of deciduous incisors can cause deflection of permanent successor (crown root dilaceration)
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What is balancing extractions?
If taking a tooth out on one side or arch may consider extracting the contralateral tooth.
- e.g extract URC consider extracting ULC
- Mostly done if concerned will cause a centre line shift during the eruption of the permanent incisors
- C's and D's most likely to have an effect
- Rarely E's
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What is compensating extractions?
If extracting one tooth in the arch considering extracting the same tooth in the opposing arch.
- Mostly considered for 6's
- If extracting a lower 6 can get over-eruption of the upper 6 which can cause occlusal interference.
- If xla lower 6 then consider xla upper 6
- If xla upper 6 then rarely need to xla lower 6
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What is a crossbite?
Can affect any tooth
Most commonly affect incisors or molars
Unilateral or bilateral
Can cause displacement of tooth and jaw
tooth wear
easily corrected in mixed dentition
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What are the effects dentally if a patient has a habit of thumb sucking?
- Typically get: proclined upper anteriors, retroclined lower anteriors, buccal segment crossbites, reduced overbite or anterior open bite
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What are some management options for a patient with a habit of thumb sucking?
- Deterrent devices/habit breakers
- Elastoplast on finger
- Encouragement
- Nail varnish
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What would be with aetiology and management of a median diastema?
Present 98% of 6 year olds
Aetiology: Normal dental development
Small teeth/large jaws
Missing teeth
Midline supernumerary
Prominent frenum
Proclined upper incisors
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What are some management options for median diastema?
- Radiograph to exclude pathology
- Try and eliminate cause if possible
- Likely to reduce as permanent teeth erupt
- Less than 3mm rarely require treatment
- Large diastema: fixed appliance, permanent retention
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How would you manage a patient with impacted E's?
Not common, usually at the distal of D's. Dental health risk which often improves with no intervention. Can place separators or extract.
150
How would you manage a patient with impacted 6's?
Not common, usually due to crowding, same management as E's
151
Name 4 reasons why you can get impacted canines.
- Crown root dilaceration
- Early loss of deciduous C
- Trauma
- Supernumerary
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What are the management options of impacted canines?
- Leave
- XLA deciduous teeth (good chance will erupt) - can use URA to align
- Remove obstruction
- Open/closed exposure
- Surgically removed canines
