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Orthodontics > Relapse and orthodontics retention > Flashcards

Relapse and orthodontics retention Flashcards

1
Q

What is Relapse ?

A
  • The Return , following correction of original features of malocclusion

OR

Unfavourable changes from the final tooth positions achieved at the end of Orthodontic treatment.

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2
Q

Stability
When relapse will occur?

A
  • Tooth position dictated by equilibrium of forces drives from :
  • Periodontal and gingival tissues
  • Orofacial soft tissues
  • Post treatment facial growth
  • Occlusion

RELAPSE OCCUR IF EQUILIBRIUM IS DISTURBED

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3
Q

Define Physiological Recovery?

A
  • Reorganisation of periodontal and gingival fibres occur following active orthodontic treatment.
  • Physiolocal recovery can result in relapse as periodontal structures under tension during treatment “ spring back” once orthodontic appliance are removed.
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4
Q

Re- organisation of Periodontal structures

Bone Prevalence

A
  • 3 Months
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5
Q

Gingiva Prevalence

A
  • Supra crestal fibre - 6 months
  • Free gingival fibre - 12 months
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6
Q

Why retainer check in 12 months?

A
  • gingival fibre takes 12months to re organise
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7
Q

Why do we see patient every 6-8 weeks?

A

Periodontal fibre takes 1-2 months to re organise

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8
Q

Oro Facial Soft tissue

A
  • Teeth were Initially positioned in neutral zone
  • Orthodontic tx may change this balance
  • The greater the change in relation to neutral zone, greater the tendency to relapse.
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9
Q

Post tx facial growth

A
  • AP changed - class 3
  • Vertical changes - AOB , OB
  • late vertical incisors crowding
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10
Q

Occlusal factor can aid Stability? E.g

A
  • Adequate overbite following correction of anterior overbite
  • Adequate overbite following correction of class 3 incisor relationship
  • Appropriate inter- incisal angle in class 2/2 cases
  • Good intercuspation
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11
Q

Overbite in class 3 incisors
InAdequate and adequate overbite

A

-Inadequate over bite - less likely to be stable
E.g removable appliances tips teeth forwards and upwards

  • Adequate overbite- more likely to stable if
    . Initial OB increased
    . Upper incisors are initially Retroclined
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12
Q

Interincisal angle class 2 div 1
Inadequate

A
  • Inadequate - Large inter-incisal angle after Overjet correction
  • Mostly seen upper incisor are Retroclined during tx rathe rather than bodily moved

Unstable result

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13
Q

Interincisal angle class 2 div 1
adequate

A
  • Lower inter- incisal angle after Overjet correction achieved due to BODILY Movement palatally.

More stable final overbite

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14
Q

Occlusal intercuspation

A
  • Good intercuspation is preferable in all cases to enchance post tx stability
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15
Q

Occlusal intercuspation affecting stability

A

-Cusp to cusp interdigitation is less than stable.

  • Anterior- posterior (half unit class 2 molar relationship)
  • lateral - associated with displacement
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16
Q

Age related changes

A
  • A decrease in arch length following age 10-19
  • inter molar width increasing until age of 13 and then static
  • Arch length and inter canine width increasing until age of 13 then Reduce

These factors can be sometimes be confused with relapse in patient who have had earlier orthodontic treatment.

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17
Q

True Relapse

A

Orthodontic treatment choices can have negative effect on the stability equilibrium increasing like-hood of relapse.

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18
Q

Example of True relapse

A
  • Altering the patient’s original arch form
  • Expanding inter canine / inter molar width
  • Proclining lower incisors excessively
  • incomplete Overjet reduction
  • incomplete correction of inter- incisal angle
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19
Q

Orthodontic Retention

A
  • Retention is phase of orthodontic treatment which maintain the teeth position after tx
20
Q

Explain Orthodontic retention

A

Orthdontic retaiers resist the tendency of teeth to return to their pre treatment positions under influence of:
- Periodontal tissue factors
- Soft tissue factors
- occlusal factors
- continue Dento facial growth

21
Q

Rationale for Retention

A
  • To allow for Re organisation of gingival and periodontal tissues
  • Minimise changes due to growth
  • Maintain position of teeth have been placed in unstable position for compromise or aesthetic reason
22
Q

Consideration when planning retention?

A

When - ideally at tx planing stage
Type- removable or fixed
Durations- 12 months/ forever ?

23
Q

Type of Retainer

A

Removable Retainers
- Vaccum formed retainer (VFR)
- Hawley

Fixed retainers

24
Q

Hawley

A
  • Labial bow 0.7mm
  • Adam cribs on 6s 0.6mm
  • Palatal baseplate
25
Q

Hawley advantages

A
  • Allow posterior settling
  • Pontics can be added for missing teeth
  • Retain posterior expansion
  • can be activated to close space
  • Can include anter bite plane to maintain OB
26
Q

HAWLEY- Disadvantage

A
  • Inferior aesthetic due to labial bow
  • Speech issues
27
Q

VFR- Vaccum form retainer

A
  • Polyvinylchloride sheets extended to atleast 1/2 coverage of terminal tooth to prevent over eruption.
28
Q

VFR- Advantages

A
  • Aesthetic
  • cheap and easy to construct
  • Improved retention of incisors
  • Pontic can be added
29
Q

VFR- Disadvantages

A
  • Less effective at maintaining expansion
  • less occlusal settling position
  • Potential for decalcification
30
Q

Fixed bonded retainer

A

Fixed Retainer are used in situation where Instability is more likely.

31
Q

Fixed bonded Retainers which cases

A
  • Correction of severe rotations
  • Periodontal disease
  • Median diastema/ closure of generalise space
  • Proclination of lower incisors >2mm
  • Teeth moved out of neutral zone
  • Following removal of lower incisors
32
Q

Fixed Retainer - Advantages

A
  • well tolerated by patient
  • Good aesthetic
  • Less compliance required
33
Q

Fixed retainer- Disadvantages

A

-Placement is time consuming with technique sensitive
- Can interfere with occlusion
- Only retain the teeth they are attached to
-High failure risk
- can fail patient realising and can cause Caries and relapse
- VFR should be worn in addition to fixed retainer
- Difficult to clean.

34
Q

Fitting fixed retainer

A
  • can be lab made or chair side
  • Sandblast enamel then Etch then bond then flowable composite
  • Place passively using floss/ silicone Jig
  • Check occlusion
35
Q

Retention protocol

A
  • Most clinician ask patient to wear removable retainer at NTO from start.
  • Some prefer an initial period of Full time wear.

-Little wood et 2016 - found NTO wear from start to equally effective as 6/12 full time wear then NTO

  • some Clinicians use more fixed retainers than others
36
Q

Advice to patient

A
  • Teeth are never set in concert and some instability is natural through out life
  • Retention peas is very important and should be discussed as part of consent process
  • Patient are advised to wese retainers for atleast one year after the end of treatment on nightly basis
  • For max preservation of alignment, some retention should continue indefinitely
37
Q

HOLD that smile

A
  • British Orthdontic Society launched 2017
  • Aim to improve patient understanding of retention and need lifelong retention following treatment .
38
Q

Role of Orthdontic Therapist

A
  • Fitting retainers under prescription
  • Good wear and care instruction
  • Monitoring wear and fit of retainers at review appointment
  • Patient with fixed retainers - check they are intact and OH is adequate. Minor repair may be carried out. If outside personal scope of practice then refer to Orthdontist.
39
Q

What factor cause relapse after tx?

A
  • Unfavourable soft tissues e.g. incompetent lips And tongue thrusts
  • unfavourable skeletal growth
  • periodontal fibre remain under tension post tx
  • inappropriate tooth position out of soft tissue balance.
40
Q

Overbite and Overjet indication for relapse?

A
  • Anterior open bite and deep bites are prone to relapse as are cases where tooth movement has been formed in order to compensate for severe skeletal discrepancies.
41
Q

Root resorption indications?

A
  • Root form - blunt, pipette shaped or short roots are more susceptible to RR.
  • Ectopic canines- palatally impacted canines increases risk of RR of adjacent incisors and premolar teeth. Due to increased tx duration
  • Trauma- Roots already showing sign of root resorption due to trauma prior orthodontic tx will be increased risk of resorption. Traumatized teeth without root resorption are at greater risk than non- traumatized teeth.
  • Treatment mechanics- Fixed appliances, rectangular wires, Class II traction, Tooth intrusion, movement of root apices against cortical bone.
  • Age- Pt with complete root formation are at greater risk of root resorption than immature root apices.
  • Gender- F>M
  • Lenght of tx- Longer tx more risk
  • Systemic problems- Endocrine disturbance such as hyperparathyroidism/ hypo may increase susceptibility tx.
42
Q

How can we minimise root resorption?

A
  • Taking full history and exam including radiographs before tx to assess any risk factor
  • if tooth has suspicious anatomy Ask GDP to take long cone periapical as baseline record.
  • Use light forces and gentle mechanism
  • minimise length of treatment.
  • Monitor during tx : Case with sign of RR in 6months are likely to have severe root resorption at the end of tx. Therefore revise treatment aims and consider stopping tx prematurely.
43
Q

Planning retention

A
  • Rotation -circumferential supracrestal fiberotomy and Inter proximal enamel reduction.
  • Diestemas- Fraenectomy
  • Deep bite- incorporate bite plane into post tx retainer
  • Required achform change- Proclination of LLS.
44
Q

Cases requiring no retention.

A
  • Anterior cross bite with adequate OB
  • Posterior crossbite with good interdigitation, adequate buccal OB and minimal buccal tipping of teeth.
  • These cases are all still susceptible to natural age change e.g late lower incisor crowding.
45
Q

Situation more prone to relapse

A
  • Expansion cases
  • Spaces cases
  • Multiple and severe rotated cases
  • Periodontal cases

Orthodontics (53 decks)

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