Emergency Management

Question 1

What form of retainer do we use for fixed rotations or diastemas and why?

Answer 1

• We mainly use fixed bonded retainers if there have been corrections of diastemas or rotations due to their high risk of relapse.

Question 2

Fixed Bonded Retainer Failure Correction Procedure

Answer 2

• If a fixed bonded retainer fails, the composite may bounce about. The patient may not be aware of this but this can cause relapse and there may be food ingress and therefore caries.
  
  • In the case of failure, we need to remove composite using a tungsten carbide bur or diamond bur down to the wire - do not damage the wire. Then prize away at the composite with an instrument to remove the composite.
  • When the composite is removed, check the tooth integrity, wire integrity, and ensure the wire has not been distorted - we need to the wire to remain intact and passive to prevent unwanted tooth movement.
    After this, we can then place etch, bond and composite.

Question 3

Fractured adams clasp and loss of adams clasp

Answer 3

○ Fractured adams clasp and loss of the adams clasp:
§ Explain what the active and retentive components are and on what teeth.
§ Account for the fractured wire fragment. If we cannot account for the fragment, send to A&E for imaging.
§ If we can account for the fragment:
□ Smooth off the wire edges and try in mouth to see if there is adequate retention, particularly if at the end of the treatment, as we still get adhesion cohesion retention from the palatal coverage, southend clasp and other adams clasp.
□ If at the start of treatment, new appliance.
□ If in the middle of treatment, get the single adams clasp replaced. The lab would remove the quadrant of the baseplate and make a new adams clasp and add more acrylic as acrylic will bond to the acrylic - give the appliance to the technician, original working cast if possible, if not, take an impression but this poses a problem because this model will be different to the original working cast (saliva and air make negatives on the impression to make positive lumps on the cast). This can cause acrylic creep as the acrylic will flow under the existing appliance - will not be flush. To overcome this, we take the impression with the appliance in situ to ensure the acrylic is flush (no big gap under the baseplate).

Question 4

Southend clasp fracture

Answer 4

§ This cannot be soldered here because it is too close to the baseplate - acrylic is highly flammable. It also cannot be soldered because it is in an area of flex.
§ We could cut in the middle of the southend clasp so it covers 1 incisor rather than 2. Bend the wire back on itself to prevent trauma (do not smooth this side because you will make it thin and sharp) and smooth the other side flush with the baseplate.
If this happened at the start of treatment, make a new appliance.

Question 5

Fixed bonded retainer failure

Answer 5

§ Test composite bonds with an ash 5.
§ We will thin composite with a tungsten carbide bur or diamond bur and flick off the composite.
§ Check the integrity of the tooth (deal with any problems), the wire and ensure that the wire is passive.
§ Etch, prime and bond and place a composite bond again with the wire.

Question 6

Wire slippage of a fixed appliance

Answer 6

§ The wire is deficient on one side and is extending out through the other side.
§ We do not attempt to pull the wire back round as we do not know where it should go - if we put it in the wrong place we will compromise the ortho. Instead, we cut the excess on the side with more wire and put a retentive tag in and we also do this on the other side and ask the patient to book an urgent appointment with their orthodontist (this will mean the short 6 on the other side will have no archwire.

Question 7

Fractured URA baseplate - happened extra-orally

Answer 7

§ Find out if it happened in the mouth or outside of the mouth.
§ Ensure patient does not fix it themselves - no superglue.
§ Ensure the patient does not wear it in its current state.
§ We can offer these patients a thermoplastic retainer to prevent relapse until they can visit their orthodontist.
§ Retainer will freeze the treatment where it is now. Need to let the patient know there is a financial cost associated but it they do not get one there will be relapse.
§ Braces can be broken if someone stands on them by accident or a patient can destroy them if they do not want them. They are not broken by dropping them.

Question 8

Fracture of adams clasp at the arrowhead

Answer 8

§ The wire can be soldered as it is not near the baseplate (as it is not in an area that requires flex).
§ If we cannot solder, we could modify the adams clasp by cutting at the edge of the bridge and curving the wire round, turning it into a single arrow head - pinching at the arrow head, cutting at the end of the bridge.
§ If we cannot do this, we could try and remove the entire adams clasp and smooth it as we still get retention from other components.
§ If this does not provide adequate retention, we can then get the adams clasp replaced - we would ideally want the working cast and appliance but if not an impression with the appliance in place.

Question 9

Transpalatal arch fracture where it meets the metal band

Answer 9

§ Cannot solder it as it is in the mouth (850-900 degrees centigrade for soldering - cannot do this in the mouth).
§ This cannot be repaired intra-orally due to excessive force required for metal bending.
§ We want to remove the transpalatal arch where the arch meets the band using a bur rather than wire cutters.
§ We secure the transpalatal arch by placing floss through the arch and getting the patient to hold it. We use a bur with lots of water coolant to prevent friction heat (use suction) - remove the component completely and smooth to the metal band and tell the patient to seek an orthodontic appointment immediately. Yes, we are compromising anchorage here but we need to do this for patient safety. We can contact the ortho for them.

Question 10

Failure of lingual bonded retainer - multiple debonds and wire is bent

Answer 10

§ We cannot stick this back on as the wire has been bent, becoming active rather than passive - no longer fit for purpose.
§ We remove the rest of the bonds.
§ We could make a thermoplastic retainer.
§ We could give a hawley retainer.
§ We could replace lingual bonded retainer.
§ We could take it off and do nothing and warn of relapse (financial cost) - ensure well documented that you spoke about the risks. We can get the patient to sign this.

Question 11

Fixed appliance with a debonded bracket (round wire):

Answer 11

§ Do not bond the bracket on again as we do not know the angulation, torque, tilt, rotation etc required - may make it worse rather than better.
§ If the bracket can be moved round the wire, the patient can move it with their tongue, we can remove the ligature, take off the bracket and take it to their orthodontist.

Question 12

○ Fixed appliance with debonded bracket (rectangular wire):

Answer 12

§ The bracket does not rotate round the wire. In this case, we cannot remove the ligature because we will bend/flex the wire, knackering it and could perhaps cause debonding of adjacent brackets.
§ Ensure the bracket has a good ligature on it.
Ask the patient to move the bracket to the side to clean it and book an ortho appointment asap.

Question 13

○ Fixed bonded retainer with composite debonding on a canine not flush against the canine and it is distorted:

Answer 13

§ Fixed lingual bonded retainers are indicated in correction of diastemas or rotations.
§ We can debond the wire distal to the 2 and smooth the wire at the 2 and add composite here if needed and if they want a replacement they should go to the orthodontist - low chance of relapse here.

Question 14

○ Fixed appliance with debonded metal band:

Answer 14

§ We do not rebond the metal band.
§ It may be sharp on the patients tongue.
§ We do not recement it because there may be underlying caries and we will be unlikely to get a good seal. We could also bond it back on in the wrong position and cause more harm than good.
§ We could take a bur to the metal band to remove it and hand it to the patient to take to the orthodontist. We then cut a retentive tag in the archwire.

Question 15

○ Fixed appliance with multiple debonded brackets (trauma):

Answer 15

§ Account for lost brackets.
§ Trauma history - does the story match up to the injury.
§ Go through paediatric trauma stamp.
§ Remove the archwire and remove loose brackets.
§ Leave on well bonded brackets.
§ Splint mobile teeth, working round the brackets.

Question 16

○ Southend clasp midline fracture on a URA:

Answer 16

§ Cannot solder this as this is an area of flex and can cause patient trauma so cannot do this.
§ Create 2 C clasps by rotating the wire back on itself.

Question 17

Acrylic creep

Answer 17

• Acrylic creep - no 2 impressions are the same and we will have imperfections ie saliva or air causing bumps on casts - appliance made in accordance to these imperfections. The impressions will have imperfections which mean that when we put the baseplate onto the impression it will not fit correctly - we will get acrylic creep under the baseplate. If we take an impression with the appliance in situ, all of the defects that were in the initial impression will be seen on the baseplate to replicate the initial impression. If the appliance is not with the appliance in situ, there will be new imperfections and the appliance will be sat on different imperfections and will not seat properly.

Question 18

2 shapes of ortho wire

Answer 18

Ortho wire can be round or rectangular in cross-section depending on the movement required. We know it is round if the bracket moves round the archwire.

Question 19

What is a space maintainer?

Answer 19

If we have a URA with retentive components and no active components this is a space maintainer.

Question 20

Account for all …

Answer 20

• Account for all components and patient safety is of highest priority.

Question 21

Bonded retainers function

Answer 21

They retain teeth in their final orthodontically corrected position and prevent relapse. Bonded retainers only retain the anterior labial segments but they are incredibly useful in the retention of the correction of rotations and diastemas. Indicated for when there has been a correction of a rotation or a diastema because otherwise the diastema will open up very quickly:

Question 22

Hawley retainer advantages and disadvantages

Answer 22

§ Disadvantages:
□ Aesthetics - can cause poor compliance.
□ Time consuming to make.
□ Expensive.
□ Palatal and lingual coverage affecting speech and comfort.
§ Advantages:
□ Removable so can be cleaned well.
□ Incorporates all teeth.
□ Strong and resilient.
□ No occlusal coverage - occlusal settling to allow teeth to find their new natural occlusion.
□ These can be activated to create a small amount of force and minor movement in minor relapse.
□ No tooth preparation required.

Question 23

Thermoplastic retainers advantages and disadvantages

Answer 23

○ Thermoplastic retainers (not essix retainers - that is a brand name):
§ They are formed using a vacuum former or pressure former - do not call them vacuum or hoover formed though, call them thermoplastic retainers.
§ The pressure former technique is more superior.
§ Advantages:
□ Aesthetics.
□ Compliance.
□ Incorporate all teeth.
□ Can be removed to maintain good oral hygiene.
□ Relatively inexpensive.
□ No tooth preparation required.
□ Well tolerated as they do not affect the palate or lingual - may affect speech minorly still.
□ Introduce small amount of force if they have not been worn for a few days to correct position.
§ Disadvantages:
□ Props the bite open slightly.
□ They should be extended back to the last erupted molar to prevent overeruption.
□ Can be removed and can affect compliance.
□ Can be malformed with heat - can distort ie if cleaned in hot water or placed on a window sill.
□ Not very strong or resilient.
□ Can become brittle and prone to fracture with time due to gradual loss of plasticiser.
□ Design cannot be modified with time.
□ Can hold substances against the teeth ie should have last sugary intake at least 1 hour before placing these in the mouth overnight to prevent sugar being held against the teeth as the pH of the saliva cannot clean the teeth over night.
□ Cannot clean with toothpaste. Just clean with soap because if we use toothpaste it is too abrasive and this can affect the colour of the retainer, making them more opaque.
□ People can wrongly use them for tooth whitening - the retainers for tooth whitening should have a well on each tooth for the tooth whitening to make a reserve.
□ Easily lost.

Question 24

Bonded retainers advantages, disadvantaged and process of applying

Answer 24

• Bonded retainers - indicated for when there has been a correction of a rotation or a diastema because otherwise the diastema will open up very quickly:
  ○ Lingual bonded retainer - wire and light cure composite:
  § Advantages:
  □ Cannot be seen.
  □ Cannot be removed - good compliance.
  □ More affordable.
  □ Small and unobtrusive.
  □ Can be done chairside.
  § Disadvantages:
  □ Teeth need to be etched.
  □ Difficult to clean as they cannot be removed - poor oral hygiene - need to apply blob of composite on every tooth individually, not a smear (otherwise impossible to clean).
  □ High failure rate - higher failure rate on uppers rather than lowers due to occlusion.
  □ No posterior teeth incorporated - no posterior retention.
  § Process of applying:
  □ We want to bend the wire for retention to create a passive retainer rather than an active one which will cause the tooth to move.
  □ Use a number 65 coil formers to bend the wire.
  □ Go from half way along a canine to half way along a canine.
  □ If doing it on upper, see where the occlusal contact is for the overbite.
  □ Introduce a bend between the central incisors.
  □ Shape around every tooth individually so it is passive.
  We can use pumice to degrease the tooth then etch and bond the teeth.

Question 25

Thermoplastic retainers procedure

Answer 25

• To make thermoplastic retainers we cut the study casts thin because the plastic will be placed over the top of the teeth and the more it has to cover the thinner the resulting retainer will be.
  
  • We block out the undercuts with plaster of paris to make it easier for the patient to put in and take out the retainer.
  • If the patient struggles to take the retainer out when it is in the mouth as them to sit with it in for 5 minutes for it to heat up and become more flexible or ask them to drink some hot water. If we cannot get it out we will have to cut it out.
  • The plastic has a spacer layer incorporated into it when it goes into the pressure former which is peeled off at the end to reveal the transparent appearance.
  • The plastic is first heated in 50 seconds to over 200 degrees centigrade, then the plastic is transferred on top of the cast under 3 bars of pressure during the cooling phase. The reason this is done under pressure is because if it is not done under pressure, whilst the plastic cools, it will return to its original configuration (contraction on cooling) which we do not want.
  • The cast will be compromised during this process.
  • Once the retainer has been formed, we use a tri-cutter to cut away excess material. We cut half way along the 7’s. We use a tricutter to do this. We then use a tungsten carbide bur followed by a silicone bur to smooth the edges. We then use a bur that looks like a big wheel fan to remove the feathered edges.
    We want to leave 2-3mm of material superior to the gingival margin as this gives somewhere for the patient to grip to put the retainer in and bring it out again.