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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.

17
Q

True Relapse

A

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

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
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 0.7mm
  • 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.

orthodontics (45 decks)

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