Restorative/DMS

Question 1

You are a GDP. A 32yo female attends for an emergency appointment with a broken 12.

The pt is F+W. She is an executive, with an important meeting tomorrow. She is keen to keep the root.

On examination, the 12 is a post-crown that has now fractured.

Describe the treatment options available to the patient

6 mins

Answer 1

Introduction - name and designation

Acknowledge - I realise this can’t be a good time for this to happen, but you’ve done the right thing coming here and we’ll do everything we can to fix it

Hx - when was the crown placed? Has it been replaced in the past? Any problems with it? how/when did it happen? Any Sx from the tooth?

Ix - PA root and adjacent teeth, vitality test adjacent teeth, perio probe, sinus/tender in sulcus

Mx - I’ll be able to tell you our options for certain once I’ve taken an x-ray of the root and the teeth either side of it. This will give us a clearer picture of what can be done.

The potential options include:

1. Doing nothing - not really an option, as leaving a space
2. Replant post-crown if root still in good condition. Irrigate with CHx/NaOCl and replant. Best option if tooth is still healthy
3. If post # - remove (USS), provide new temp post and temp crown - technical, risk of root #, may not be able to remove post. Take care not to bite on it as will be v fragile. Long-term, impression for new post-crown. Retain root
4. If post still sound, temp crown only. As per 3
5. If unrestorable/root # - impression for immediate RPD + XLA and fit in few days. Good aesthetics restored, but lose root, removable replacement, need 3/12 before considering replacement. Unlikely to be possible as need for tomorrow
6. If can’t recement, temp adhesive bridge (ProTemp/composite) - etch 11 and 13. V fragile, don’t bite on it, v soft diet. Not a great solution, but possible (or temp bridge with crown, but needs to be a material that could bond)

Long-term options - RPD, bridge (RRB/conventional cantilever), implant

Does that all make sense? Do you have any questions?

Question 2

You are a GDP. A 42yo male new patient presents C/O sensitivity in his 46. He is F+W.

You take a bitewing x-ray (provided) - photos 13, and the tooth demonstrates a vital response to sensibility (EPT and ECl) testing

Discuss the diagnosis and treatment options with this patient

You do not need to take a history

6 mins

Answer 2

Introduction - name and designation

Dx - caries, encroaching on pulp - likely reversible pulpitis.

Now that we have the results from the investigations, would you like me to go through them?

So the tooth that’s been giving you bother, one on the bottom right near the back has extensive decay in it. On the x-ray the decay has broken through the outer and middle layers of the tooth and is closely approaching the inner layer of tooth. This is called the pulp. The pulp is responsible for keeping the tooth alive and supplies it with small nerve endings. When decay starts to get close to the pulp, the pulp tries to fight it and gets irritated, which causes symptoms like sensitivity or pain. This is the tooth’s way of letting you know there’s something wrong.

The decay has to be removed to stop it progressing any further, or there’s a risk that the tooth will become extremely sore or develop an abscess. At the moment it looks like we can repair the tooth rather than take it out.

So our options would be remove the decay and put in a filling or remove the tooth. If we were to remove the decay and put in a filling, we would numb you up, stretch a sheet of rubber dam over the tooth to help keep it clean and prevent any saliva contaminating it, remove the decay with a drill and then assess what we have left. At that stage we might stop, put a temporary filling over the tooth to seal in some of the decay and then review you back in around 3/12 or so. At that stage we would expect the decay to have stopped progressing and we can safely remove it before putting in a permanent filling. If it was still causing you bother, we would have to do a root canal to get rid of the symptoms.

Alternatively, we can try to remove all of the decay today. The risk with this would be that the decay is quite close to the pulp, so there’s a chance that when we’re removing it, we nick the pulp and expose it. If this happened, we would need to put a cap, or a seal over the top of it if it was a small exposure or start a root canal treatment if it was a larger exposure. There’s also a chance that the decay is more extensive than we can see on the x-ray and might already be in the pulp. If this is the case, we will have to do a root treatment.

Risks of root treatment are failure, pain, instrument separation, hypochlorite accident or perforation, but the alternative would be extraction so it means you would get to keep the tooth.

Does that all make sense? Do you have any questions? Do you have any preferences?

Question 3

You are a GDP. A 16yo female presents C/O the appearance of her upper teeth.

You undertake an exam, which reveals evidence of loss of tooth substance on the labial and palatal surfaces of upper anterior teeth

Discuss your diagnosis and management option with the patient

6 mins

Answer 3

Introduction - name and designation

Hx - how long for, any other Sx (sensitivity), any idea on the cause, how does it make you feel?

Reassure - we will do what we can to help, I just have a few more questions if that’s alright?

MH - do you suffer from reflux? Do you take any medications? What is your diet like? Do you ever throw up after eating?

You have something called tooth erosion. Erosion is caused by acids and wears away the surface of teeth. Acids are in certain foods and drinks - fruits and fizzy drinks mainly, but can also be caused by vomiting frequently.

Has your GP ever spoken to your diet? Can I ask if you’ve noticed any recent weight loss? Do you have any concerns about how you look? Do you every feel any pressure to look a certain way, from friends, family or even yourself?

I think that in your case the tooth wear might be being caused by something called bulimia. This is when you eat and then quite quickly throw up. Would this be right? Would you like to tell me about it?

To manage this properly, we would need to speak to your GP. Would you be happy with me doing this and letting them know what we’ve spoken about and then they will arrange an appointment to speak to you? They might also involve someone who specialises in managing things like. In terms of your teeth, I’ll give you extra strong toothpaste to help harden your teeth. Use this twice a day for two minutes each day. We can also look at building your teeth back up with white filling materials, which will help prevent any further erosion.

It’s important to say that if you do vomit, not to brush your teeth for around 30 mins after. This is because when you vomit, the acid softens the tooth and if you brush soon after, you start to brush the tooth substance away. Try to either rinse out with water or even a mouthwash and then brush your teeth 30 mins after.

Today, we’ll take some impressions and photos of your teeth. This will help us monitor the future progression and will help with planning treatment. We’ll give you a prescription for the toothpaste and paint some extra strong varnish on your teeth to help strengthen them.

Does that all make sense? Do you have any questions?

Question 4

You are a GDP. A 28yo female patient requires a DO restoration on tooth 15.

She would like to know the differences between the restorative materials that could be used.

Discuss this with the patient

6 mins

Answer 4

Introduction - name and designation

2 materials - composite and amalgam

Composite advantages - good aesthetics, less destructive (less tooth drilling), support for remaining tooth tissue, bonds to tooth, low thermal conductivity, no galvanism, good long-term performance, repairable, command set

Composite disadvantages - PCS, marginal integrity, post-op sensitivity, low # toughness, high elastic deformation, technique/moisture sensitive, hydrolytic breakdown, limited depth of cure, high thermal expansion coefficient, reduced wear resistance, higher cost

Amalgam advantages - user-friendly, strong, durable, good long-term performance, radiopaque, high elastic modulus, high hardness, low cost, good wear resistance, less technique sensitive

Amalgam disadvantages - poor aesthetics, doesn’t bond to tooth, high thermal diffusivity, more destructive prep, marginal breakdown, tooth discolouration, ditching (long-term corrosion at margin), lichenoid reaction, amalgam tattoo. Reduced disadvantages with bonded amalgam

GIC advantages - relatively good aesthetics, release F/reservoir, chemical bond to tooth, low microleakage, good thermal properties, no PCS

GIC disadvantages - brittle, poor wear resistance, moisture sensitive when placed, poor handling characteristics, susceptible to acid attack, dry out over time, aesthetics not excellent

Does that all make sense? Do you have any questions?

Question 5

You are a GDP. A 50yo new patient presents with a fixed-fixed coventional bridge from 14-24. The abutment teeth and remaining molars are mobile.

The pt has a strong gag reflex and T2DM. He would like to know if he can have implants

Discuss the possible treatment options and factors affecting the success/failure of an implant-retained bridge

6 mins

Answer 5

Introduction - name and designation

Brief Hx - how long had bridge, ever been replaced, where was it placed, aware of how it’s doing (failing)

MH - well-controlled or not?

Ix - XRs of abutment teeth, sensibility testing, perio probing.

Options - leave (no Sx, but failing)
RPD - removable, cheaper, less complex, easy to add teeth onto/adjust; bone resorbs, limited retention, gag reflex
Not another bridge - span too long, excessive pressure/force on abutments
Implant - fixed, avoids damage to adjacent teeth, better aesthetics, good long-term solution; expensive, complex, still may fail (peri-implantits), may require bone grafts.

Factors influencing success - bone level (quality, quantity, density), OH, existing perio disease, diabetes control, occlusal trauma, unrealistic expectations, RTx

Would need to refer to implant specialist for assessment

Does that all make sense? Do you have any questions?

Question 6

You are a GDP. A 24yo female new patient presents C/O discoloured teeth.

List 4 intrinsic and 4 extrinsic causes of tooth discolouration and discuss the treatment options for discolouration with the patient

6 mins

Answer 6

Introduction - name and designation

Intrinsic - dental materials (amalgam), tetracyclines, fluorosis, hypoplasia, ageing, AI/DI, CF, pulpal necrosis

Extrinsic - tannins, smoking, CHx, Fe supplements, chromogenic bacteria

There are a few options we can do to try to improve the appearance of your teeth.
Options we can use are:
Tooth whitening - aim to lighten the teeth to the colour of unaffected teeth. We would take impressions to make trays and then show you how to put the bleaching gel in the tray and you’d need to wear it for at least 2 hours a day. Easy and usually has good results, but can cause sensitivity, relapse and gingival irritation
Microabrasion - uses acid and a polishing powder to remove the outer layer of enamel to improve the appearance. Because of this, it may not improve the appearance of deeply stained teeth. Minimal damage to enamel.
Internal/combo bleaching - for root treated teeth only. Good results, bleach from inside/inside and outside. Good success, risk of cervical resorption
Localised composite placement/veneer - placing a thin layer of white filling material over the top of the tooth, to fill in any areas of breakdown as well as masking the staining. No drilling but adds bulk to tooth.Has to be thin, so sometimes doesn’t cover very dark stains.
Veneer/crown - destructive prep, excellent aesthetics, restorative cycle, risk of failure and tooth loss, unstable gingival margin level.

Does that all make sense? Do you have any questions?

Question 7

You are a GDP. A F+W 18yo female new patient attends with an RPD replacing tooth 11. She would like a non-removable option to replace this.

Discuss investigations required and the treatment options that may be available to her

6 mins

Answer 7

Introduction - name and designation

Hx - concerns, how long had RPD, what happened to the tooth, problems with RPD (retention, smile line)

MH - smoker, diabetes, other conditions/meds

Ix - XR of space and adjacent teeth (to check bone quality and quantity and health of adjacent teeth), sensibility tests, perio considerations, occlusion (study models), photos ± CBCT for implants

Options - there are a few options that we can use to fill the space

1. Do nothing - no treatment, left with space. Obviously cheapest but not really an option
2. RPD - replace denture and improve on problems, however still removable and not really an option of you want a fixed replacement tooth that you don’t have to take in and out
3. Ortho space closure and masking - use braces to close the space and re-align the teeth. Would be left with a space during treatment and once the space is closed would need to camouflage the teeth with white filling material to make them look like other teeth and make it symmetrical. Good results, but quite expensive, gap during treatment, long treatment time, decal, relapse, root resorption
4. Bridge - a few options. RRB - have a false tooth hanging off a tooth beside it. Minimal/no prep required, stick a metal wing to back of one/two teeth beside it. Cheaper than alternatives and fixed, good success rates, if fails/falls off, can stick it back on. Risk that it could fall off, particularly if you bite heavily on it, risk that the metal wing might shine through and cause problems with aesthetics, limited lifespan, but can replace. Conventional cantilever/fixed-fixed - this would involve cutting down one/both teeth beside the space and sticking a false tooth to a crown. The crown would go over the tooth that has been cut down and the false tooth would fill the space. Good aesthetics, less likely to fall off, more expensive, more extensive destruction of tooth, 20% chance tooth will die off and need root treatment.
5. Implant - final option would be an implant, which we would have to refer you for. An implant is a false tooth that is held in by a screw that is screwed into the bone. It’s not stuck to any teeth beside it, so doesn’t need teeth to be drilled/doesn’t put stress on other teeth. They have the best aesthetics and have good long-term success, but are very expensive and can be quite a long complex process of needing bone grafts, placing the screw, allowing it to heal (temp over the top) before placing the final implant. You may have to wait a few years as well until your gum level has stabilised and stopped changing.

Does that all make sense? Do you have any questions?

Question 8

Identify indirect restorations and their cements.

Describe pre and post-cementation checks that should be carried out

6 mins

Answer 8

GIC (Aquacem) - metal posts, zirconia, MCC, gold

Dual-cure comp (Nexus/Rely X) - composite onlays, porcelain onlays/crowns, veneers, fibre posts

Anaerobic-cure comp (Panavia) - RBB

Pre-cementation checks (on cast) - correct patient/restoration, no rocking, IP contacts, marginal integrity, aesthetics, no damage to adjacent contacts, static and dynamic (lateral excursion) occlusion.
Remove - check thickness with callipers and check occlusion without restoration on (shim stock)

Cementing - airway protection, repeat pre-cementation checks, cement

Post-cementation checks - remove excess, no marginal gaps/voids/overhangs, IP contacts exist and are clear (floss), occlusion (static and dynamic), cleanable, pt happy with aesthetics and feel

Question 9

You are a GDP. You have prepared tooth 36 on a F+W 57yo for a gold shell crown. It is to be cemented today.

Undertake pre-cementation checks and then cement the crown

6 mins

Answer 9

Before pt arrives - check name, work matches prescription, any deficiencies/air blows.
Check contacts, blobs, shade, die and adjacent teeth for rubbing/damage, margins, nothing sharp. Check static and dynamic occlusion on cast with and without restoration

Mouth - check the temp, remove it. Clean prep. Place throat pack, dry tooth, wash/dry crown, ensure correct orientation, seat with sticky stick.
Check margins flush, no rocking/canting/tipping, retention and resistance forms, no overhangs/voids, emergence profile.
Get pt to close slowly, remove finger, check dynamic and static occlusion. Adjust as necessary
When all good - remove, clean, dry, dry tooth, CWR/dryguard. Fill crown with cement, seat with firm pressure, get pt to bite hard. Remove excess, floss IP, check occlusion and aesthetics

Question 10

Assess this crown on the cast and determine what, if any, faults and present and how you would fix the faults

6 mins

Answer 10

Pre-cementation checks - correct restoration for correct patient?

Check on cast - rocking, canting, tipping, M/D contacts, marginal integrity (flush, no overhangs), static and dynamic occlusion (no interference), aesthetics.
Remove from cast - check for air blows/voids/blobs inside and out. Check contact points on adjacent teeth on cast for rubbing/damage. Ensure natural tooth not contacting when restoration removed

If no other teeth contacting when crown on, inadequate reduction of tooth/core. Remove crown from cast, check occlusion with shim stock (check for under-prep). Use BPE probe to check reduction. If contact when crown removed - under-prep

Check crown thickness using callipers (0.5mm circumferential, 1.5mm functional cusp, 1mm non-functional cusp).

Mx - calculate amount of interference (adjust incisal pin, calculate difference). If able to, adjust crown and cement (if won’t make too thin). If not, re-prep, check reduction and send new impression to lab.

Prevention - check prep reduction before impression, use sectional putty index for prep, measure crown thickness before cementing

Question 11

You are a GDP. A 58yo male, new patient presents with no complaints.

After completing an exam and taking x-rays, you discover that he has a post-core in tooth 45. This is carious and there does not seem to be any evidence of a root filling on the XR

Discuss this with the patient and the treatment options that may available to him

6 mins

Answer 11

Introduction - name and designation.

Findings - you have a tooth in the bottom right that has a crown on it. When was this placed? Any problems with this tooth? What I have found on the x-ray is that there is some decay in that tooth. The tooth has a post in it, which is holding the crown in. It is strongly advised that when you put a post in that you do a root treatment on the tooth first, however there doesn’t seem to be any evidence of this on your tooth - do you know anything about that?

Show XR - here’s the tooth, the crown, the root, the post. Here’s the decay. Here’s where the root treatment would normally be.

There are a few options for what we can do with this tooth.

1. Do nothing - because it’s not giving you any bother, we could leave it. However there is active disease in the tooth and without intervening that’s only going to progress and get worse. It will likely cause you bother and you might get an abscess and we might have no choice but to take the tooth out due to the extent of the disease
2. Replace crown - if the decay is coronal, we can remove the crown using some instruments and remove the decay. As long as this wasn’t undermining the post, we could leave the post and put a new crown on once the decay had been removed. However there is a chance that this post could be disrupted and it doesn’t resolve the issue of no root treatment, which leaves a large risk of the tooth becoming infected at the root, causing an abscess and needing to come out
3. Dismantle post-crown, caries removal, RCT - the tooth is still restorable and this would be the gold standard option for treating it. We would remove the crown and the post, remove the decay, perform the root treatment which would involve removing the nerve, disinfecting and shaping the centre of the tooth and then putting in a new post and a new crown. Although the gold standard treatment option, there’s a risk that the root/core/post could # during treatment, making the tooth unrestorable. During root treatment, there are risks of perforation, instrument separation and hypochlorite accident, all of which could leave the tooth unrestorable. It will take multiple appointments and be expensive, but you get to save the tooth
4. Periradicular surgery - this option would involve removing the decay and then using surgery to go in from the endo of the root and back fill the tooth up to the post. It is very complex, could be expensive and would involve referral to a specialist
5. XLA - the final option would be to remove the tooth. This removes the source of the infection and would be the cheapest option. Risks of this include tooth #, needing a surgical, temp/perm altered numbness from injection. We would then look at filling the space with a replacement tooth (RPD, bridge, implant), however these options are not as good as natural teeth.

Does that all make sense? Do you have any questions?

Question 12

Complete a prescription for a conventional cantilever bridge

6 mins

Answer 12

Details - pt details on all 3 sheets
Attach photos and relevant MH (allergies to materials), GDP details
Date and time of imp and date and time when work requried
Plan - stage, present work, other lab work
Instructions - please pour up imp with 100% improved stone, mount on DENAR II semi-adjustable articulator using facebow/wax bite/bite reg provided.
Construct metal ceramic conventional mesial cantilever bridge to replace tooth XX. Use XX as abutment and XX as pontic.
Shade XX
Staining, special effects, surface features and finish.
Type of pontic - modified ridge-lap (upper anteriors), dome-shaped (lower anteriors).
Please construct in canine guidance and ensure pontic is free of excursive movements.
Please return bridge on cast
Signature

Question 13

Place a direct pulp cap on tooth 36 following iatrogenic pulpal exposure on the mesial axial wall.

Assume dam has been placed

6 mins

Answer 13

HH, PPE

Indications - no Sx, vital, small exposure, recent, surrounded by firm dentine

Dam, stop bleeding with CW pledget and sterile saline
Irrigate with CHx and dry with CW pledget
Cover exposure with setting CaOH (Dycal)
GIC (Vitrebond) liner over tom
Restore (consider 3/12 temp for Sx)
If Sx resolve - permanent restoration. If not, RCT

Question 14

Prepare tooth 11 for a veneer

12 mins

Answer 14

HH, PPE
Seating position - 12 o’clock

Putty matrix x2 - one for temp, one for prep reduction determination (sectioned)
Chamfer bur - 3 depth grooves buccally (0.5mm). Ensure 2 plane reduction. Connect notches/grooves
Incisal edge reduction - 1mm
Bevel incisal edge (3 planes)
Ensure inter proximal finish line (chamfer) extends to gingival margin and into embrasures (short of contact point)
Smooth prep (comp finishing bur/enhanced point/disc)
Ensure no undercuts
Impression
Temp

Question 15

Prepare an MO cavity on tooth 14

12 mins

Answer 15

HH, PPE

Identify and remove carious enamel
Remove enamel to identify maximal extent of the lesion at ADJ and smooth enamel margins (ensure ADJ margins are caries-free)
Progressively remove peripheral dentinal caries (from ADJ progressively deeper)
Remove deep caries over pulp
Outline form modification
Internal design modification

Ensure conservative prep, no damage to adjacent teeth, margins cleared of contact

Question 16

Isolate tooth 35 for an MOD cavity using dental dam

6 mins

Answer 16

Select clamp (K clamp on 36)
Punch dam (34-36)
Stretch dam over clamp, place on 36, stretch dam forward
Wedjet 33/34 contact
Floss ligature 35

Question 17

Isolate 13-23 using dental dam

6 mins

Answer 17

Punch 6 holes, place dam
Wedjets 13/14 and 23/24 contacts
Floss 11 and 21
Opaldam if required, don’t cover nose

Question 18

Restore a DO cavity on tooth 46 with amalgam

12 mins

Answer 18

Dam, check prep (narrow isthmus, undercuts/retentive tags, >2mm depth)
Vitrebond liner over pulp floor (away from approximate margins)
Matrix band, wedge, burnish band against adjacent tooth
Pack in to build up wall and into corners
Remove excess, burnish into margins, carve
Remove wedges and band, carve, polish

Question 19

Prepare a distal cavity on tooth 11

12 mins

Answer 19

Access palatally
Identify and remove carious enamel
Remove enamel to identify maximal extent of the lesion at ADJ and smooth enamel margins (ensure ADJ margins are caries-free)
Progressively remove peripheral dentinal caries (from ADJ progressively deeper)
Remove deep caries over pulp
Outline form modification
Internal design modification

Ensure conservative prep, no damage to adjacent teeth, margins cleared of contact. Leave thin layer of buccal enamel when undertaking prep - controlled break at end

Question 20

You are a GDP. You are undertaking an RCT on 16. During treatment, a file fractures

Explain the problem and how you will proceed to the patient

6 mins

Answer 20

Stop what you are doing, sit pt up.
Introduction - name and designation

Explain what has happened - when we discussed the treatment at the start, we discussed some of the risks involved - perforation, file #, hypochlorite accident, failure, pain.

Unfortunately a small file has fractured/separated in the canal. These files are very thin and small and are used to clean out the pulp tissue and shape the canal for filling. I am very sorry this has happened and will explain the options to you, but do you have any initial questions?

I’ll take an x-ray to find where the file has broken and is stuck. The treatment options depend on where it is. If it is towards the mouth side of the root, so not too far down, we can try to remove it using some of the cleaning liquids which softens the tooth around it. We could also try to use an ultrasonic scaler to try and disrupt it or we could possibly work around it/bypass it.

If it’s towards the end of the root, we might be able to accept that the canal is clean and disinfected and keep going with the treatment and fill the canal. This is associated with reduced success/a poorer outcome. It has an even poorer outcome if we did this when it wasn’t far down the tooth.

Another option would be to refer you to a specialist who might be able to retrieve it using other techniques, either down through the canal or by using surgery. They’d make a small cut in the gum at the top of the tooth and work backwards through the end of the root, before putting a filling in the root.

The final option would be to cut our losses and just take the tooth out now. This would involve fewer appointments and will be cheaper. There’s risk that the root treatment will fail, so taking the tooth out will ensure this doesn’t happen. However you will be missing a tooth and nothing that we can put into the gap (RPD, bridge, denture) is as good as a natural tooth.

Does that all make sense? Do you have any questions or ideas on what you’d like to do?

Question 21

You are a GDP. You are undertaking an RCT on 16. During treatment, you cause a perforation

Explain the problem and how you will proceed to the patient

6 mins

Answer 21

Stop what you are doing, sit pt up.
Introduction - name and designation

Explain what has happened - when we discussed the treatment at the start, we discussed some of the risks involved - perforation, file #, hypochlorite accident, failure, pain.

Unfortunately a small hole has been created. Sometimes these occur when the decay is very extensive, sometimes due to complex/unusual anatomy or sometimes due to very narrow canals or when we’re cleaning and shaping the tooth. I am very sorry this has happened and will explain the options to you, but do you have any initial questions?

I’ll take an x-ray to find where the file has broken and is stuck. The treatment options depend on where it is. Depending on where it is, there’s a chance that we could repair it by covering over the hole with a material, however this is associated with a poorer outcome.

If it’s towards the end of the root, we might be able to try a different filling technique, which might seal over the hole for us.

Another option would be to refer you to a specialist who might be able to fill the hole using other materials and techniques, either down through the canal or by using surgery. They’d make a small cut in the gum at the top of the tooth and work backwards through the end of the root, repairing the perforation before putting a filling in the root.

The final option would be to cut our losses and just take the tooth out now. This would involve fewer appointments and will be cheaper. There’s risk that the root treatment will fail, so taking the tooth out will ensure this doesn’t happen. However you will be missing a tooth and nothing that we can put into the gap (RPD, bridge, denture) is as good as a natural tooth.

Does that all make sense? Do you have any questions or ideas on what you’d like to do?

Question 22

Isolate tooth 16 for a root treatment and explain what you are doing

6 mins

Answer 22

Punch hole - position over mouth, line up hole, remove from mouth, punch
Select correct clamp (K clamp) - stretch through dam, place on tooth with clamp forceps. Stretch frame around outside of dam, ensuring tight and full isolation
Use flat plastic to ensure dam tight under clamp, tight around tooth, no gaps
Seal with sealant/caulking agent
Test with CHx (minty taste)

Question 23

You are a GDP. A 54yo male new patient attends for an exam, with no presenting complaints.

Your examination and radiographs demonstrate a failed RCT on tooth 46.

Describe how you can tell that the RCT has failed and explain the potential causes for this and the treatment options to the patient

6 mins

Answer 23

Introduction - name and designation

From the x-ray it looks like you’ve had a previous root treatment on one of your lower right back teeth. Looking at the x-ray it looks as if there may be signs of failure (Sx still present, PAP same size/larger/new PAP, continuing root resorption). Have you had any problems with it? When was it done?

There are a number of reasons that it may have failed - filling not reaching the end of the root, going to far out the end, not tightly packed, voids, missed canals/accessory canals, inadequate prep, perf, vertical root #, file #, incomplete debridement, blockage, apical transportation/zipping, ledge/obstruction, elbow formation, poor coronal seal, failed restoration

There are a few options going forward

1. We can do nothing and observe it, however it’s likely to flare up and cause some bother
2. We can replace the seal over the top and the restoration, if either of these are the problem
3. We can re-root treat the tooth, repeating the process to see if we can do any better. It’s likely to have some benefit, but is associated with reduced success
4. Refer you for root end surgery - this is when they make a small cut in the gum above the root and work their way backwards up the tooth from the end. It’s more complex, is more expensive is invasive and is not without risks
5. XLA - remove the tooth and replace it with a false tooth (RPD, bridge, implant). This will be cheaper but you will lose a tooth and although we can replace it, the replacement won’t be as good as a natural tooth

Does that all make sense? Do you have any questions or any idea what you’d like to do?

Question 24

Describe the access cavity shapes and number of canals in each tooth

6 mins

Answer 24

Upper 1 - triangular, base to incisal edge. 1 root, 1 canal
Upper 2 - triangular, base to incisal edge. 1 root, 1 canal
Upper 3 - rounded rectangle. 1 root, 1 canal
Upper 4 - rounded, wider BP than MD. 2-3 roots, 1 (6%), 2 (93%) or 3 (1%) canals
Upper 5 - rounded, wider BP than MD. 1-3 roots, 1 (75%), 2 (24%) or 3 (1%) canals
Upper 6 - quadrilateral, more MB than DP. 3 roots, 3 (7%) or 4 (93%) canals
Upper 7 - quadrilateral, more MB than DP. 3 roots, 3 (63%) or 4 (37%) canals

Lower 1 - triangular, base to incisal edge. 1 root, 1 (58%) or 2 (42%) canals
Lower 2 - triangular, base to incisal edge. 1 root, 1 (58%) or 2 (42%) canals
Lower 3 - rounded rectangle in centre. 1 root, 1 (94%) or 2 (6%) canals
Lower 4 - rounded rectangle in centre. 1 root, 1 (73%) or 2 (27%) canals
Lower 5 - rounded rectangle in centre. 1 root, 1 (85%) or 2 (15%) canals
Lower 6 - trapezium, wider BL mesially than BL distally. 2-3 roots, 3 (67%) or 4 (33%) canals
Lower 7 - trapezium, wider BL mesially than BL distally. 2 roots, 2, (13%) 3 (79%) or 4 (8%) canals

Question 25

You are a GDP. You have just completed an RCT on tooth 16 on this F+W 42yo female.

Discuss the restorative options for this tooth with the patient

6 mins

Answer 25

Introduction - name and designation

Hx - how has the tooth been? Any Sx?

Explain - now that the tooth has been root filled, we need to place a filling over the top of it because we had to remove some of the tooth so we could access down into the canals. There are a few options for this.

1. Onlay - this is called a partial coverage restoration. It is a filling made in the lab and supports the tooth, protects the cusps and reduces the risk of tooth #. It would only involve removing a little bit more tooth, but is expensive (private)
2. Crown - a crown is a full coverage restoration - essentially a cap that sits over the tooth. It also supports the tooth, protects the costs and reduces the risk of tooth #. However it involves removing more tooth and is better if there is limited tooth tissue remaining, because the work required to make the tooth ready for a crown can weaken the tooth. It is cheaper than an onlay and does had good long-term outcomes
3. Amalgam - cheap, easy to place, strong; doesn’t support the remaining tooth tissue, risk of tooth #, leakage undermining it. Silver
4. Composite - bonds to tooth, but limited support to the tooth, limited cusp protection, likely to wear.

If limited tooth tissue remaining - core to retain crown (Nayyar - not ideal; GI better) ± post (cast metal) to retain core - not favoured in posterior teeth - difficult to place, risk of perf

Does that all make sense? Do you have any questions or any ideas on what you’d like to do?

Question 26

You are a GDP. A F+W 38yo female attends for RCT on tooth 26.

Obtain consent by explaining the procedure, risks, benefits and alternative options to her

6 mins

Answer 26

Introduction - name and designation

Hx - any Sx, how have you been, keeping well, any recent MH changes

So the plan for today is to do a root treatment on one of your upper back left teeth. I’ll talk you through the plan just now and see what you think, and if you’re happy we can get going, does that sound alright?

Consent via SPANNERS

Success rate - root treatments have a 70-90% chance of this working, which is relatively high

Purpose - the reason we are suggesting doing a root treatment is because there is infection at the end of the root of the tooth. This occurs when the tooth becomes decayed and the bacteria in the decay work their way down into the centre of tooth and then all the way down to the end of the root. The body recognises this and tries to mount a response, but often requires help to remove the source of the infection, rather than just reacting to it

Alternatives - the alternative to this would be taking the tooth out. Doing this would also remove the source of the infection, but you’d be left with a gap. The tooth is still restorable though however, so the root treatment gives us a good shot at keeping the tooth. If this fails, there is still the option to take it out, whereas if we take it out, we lose this option. The other option that I have to give you is the option of doing nothing, however I wouldn’t recommend that as it does nothing to solve the problem and increases the chance of the tooth flaring up and causing an abscess

Nature of treatment - so what’s involved? It involves multiple relatively long appointments, where we numb you up with an injection into the gum, stretch a sheet of rubber over the tooth to keep it isolated and clean, use a drill to remove decay and then drill into the middle of the tooth so we can find the canals. Once we’ve found the canals, we remove the nerve and blood products, clean and shape (disinfect) the canals and fill them, before sealing over the top and restoring the tooth. In between appointments we’ll put a temporary dressing in to help any pain calm down

Numbers - it’s a good bit more expensive that the alternatives, but likely comparable/cheaper than filling the space left by the extracted tooth

Effects - doing this means you get to keep your own tooth, which gives the best aesthetics and function. It often resolves the Sx and can be redone if it fails

Risks - there are a few risks we have to make you aware of. Not doing it increases the risk of abscess/swelling/pain - this might lead to the tooth having to come out or you being hospitalised with it and needing antibiotics. Risks associated with doing it include pain, failure, perforation, file #, hypochlorite accident, nerve damage from the anaesthetic (temp/perm altered/loss of/painful sensation). There’s also a risk that we try but the tooth is unrestorable so we have to take it out

Specific - any pt specific complications (limited mouth opening, anxiety, unable to sit for long, finances, complex anatomy, condition of the rest of mouth)

Does that all make sense? Do you have any questions or ideas on what you’d like to do?

Question 27

List the order of endo hand files

6 mins

Answer 27

ISO - 6 (pink), 8 (grey), 10 (purple)
15 (white), 20 (yellow), 25 (red), 30 (blue), 35 (green), 40 (black), 45 (white), 50 (yellow), 55 (red), 60 (blue), 70 (green), 80 (black)

ProTaper sequence - ISO 10, 15 to 2/3
S1 (purple), Sx (orange) to 2/3
ISO 10, 15, S1, S2 (white) to length
F1 (yellow), F2 (red), F3 (blue), F4 (black), F5 (yellow) to length as required

Re-treatment - H files, C+ files, ProTaper D1, D2, D3 or Reciprocal
Solvents - EDTA, NaOCl, eucalyptus oil, chloroform

Question 28

You are a GDP. A 72yo male attends for a checkup up. He is F+W and has a P/- CoCr denture.

Clinical photos are provided and show widespread erythema on his palate, in the shape of his denture.

Clinical photos - photos 14

Explain to the patient what the problem is and how to treat it

6 mins

Answer 28

Introduction - name and designation

Ask - do you were your denture at night? What do you do to keep your denture clean? How often? How old is your denture?

Dx - denture stomatitis

Explain - you have something called denture stomatitis, which is a localised infection in the mouth caused by yeast or fungus. It is a relatively common probably - around 30% of people with dentures will develop it at some point. Stomatitis is a fancy word for inflammation of the lining of your mouth. In this case it is on the roof of your mouth and is caused by wearing your denture and not giving your mouth a chance to recover by leaving it out at night. It’s like if you were wearing shoes all day and night, if you didn’t take them off, you wouldn’t give your feet a chance to recover. Denture stomatitis is made worse if the denture is not cleaned regularly. A fungus/yeast called Candida attaches onto the surface of the denture and colonises it. Because the surface of the denture is in contact with the roof you your mouth, the candida infection develops in your mouth as well.

The good news is that this is relatively straightforward to treat. It involves brushing the roof of your mouth daily, just as you would brush your teeth, and also keeping your denture nice and clean. You can do this by taking your denture out after meals and brushing it with a soft toothbrush and denture cream, or a detergent - like washing up liquid. You should also soak it in CHx MW for 15mins twice a day (or OCl/alkaline disinfectant) and rinse it before putting it back in.

You should also leave the denture out at night and try to keep it out as often as possible over the next week or two, while we treat the condition. Have you noticed any problems with how the denture fits? We’ll have a look to see and if it’s not fitting perfectly, we’ll look at how we can improve that, either by adjusting it or making a new one.

Do you smoke? If so, smoking is thought to contribute to increase the risk of getting denture stomatitis, as well as increasing your risk of getting mouth cancer, lung cancer and other problems with your heart and lungs, so I would strongly encourage you to stop, or at least really try to reduce your smoking. The fungus feeds on sugars from your diet as well, so try to limit your sugar intake in foods and drinks.

We’ll review you in a week or so to see how things are going. If it’s not made a difference, there are a few other things we can try.

Does that all make sense? Do you have any questions?

What antimicrobial agent would you prescribe to treat this condition?
None or Chlorhexidine
If it doesn’t resolve - fluconazole 50mg 7/7 OD
Or miconazole oromucosal gel 20mg/g 80g. Pea-sized amount to fit surface after food QDS

Not ideal, but also nystatin oral suspension 100,000units/ml, 30ml. 1ml after food QDS 7/7.

Question 29

You are a GDP. A 67yo male attends for a checkup up C/O soreness in the roof of his mouth. He has atrial fibrillation, which he takes 5mg of warfarin daily for, and T2DM. He has F/F dentures

Clinical photos are provided and show widespread erythema on his palate and a swab shows C. albicans colonisation

Clinical photos - photos 15

Explain to the patient what the problem is and how to treat it

6 mins

Answer 29

Introduction - name and designation

MH - I see that you have diabetes. What do you do to manage this? How have your blood sugar levels been recently?

Ask - do you were your denture at night? What do you do to keep your denture clean? How often? How old is your denture?

Dx - denture stomatitis

Explain - you have something called denture stomatitis, which is a localised infection in the mouth caused by yeast or fungus. It is a relatively common probably - around 30% of people with dentures will develop it at some point. Stomatitis is a fancy word for inflammation of the lining of your mouth. In this case it is on the roof of your mouth and is caused by wearing your denture and not giving your mouth a chance to recover by leaving it out at night. It’s like if you were wearing shoes all day and night, if you didn’t take them off, you wouldn’t give your feet a chance to recover. Denture stomatitis is made worse if the denture is not cleaned regularly. A fungus/yeast called Candida attaches onto the surface of the denture and colonises it. Because the surface of the denture is in contact with the roof you your mouth, the candida infection develops in your mouth as well.

The good news is that this is relatively straightforward to treat. It involves brushing the roof of your mouth daily, just as you would brush your teeth, and also keeping your denture nice and clean. You can do this by taking your denture out after meals and brushing it with a soft toothbrush and denture cream, or a detergent - like washing up liquid. You should also soak it in CHx MW for 15mins twice a day (or OCl/alkaline disinfectant) and rinse it before putting it back in.

You should also leave the denture out at night and try to keep it out as often as possible over the next week or two, while we treat the condition. Have you noticed any problems with how the denture fits? We’ll have a look to see and if it’s not fitting perfectly, we’ll look at how we can improve that, either by adjusting it or making a new one.

Do you smoke? If so, smoking is thought to contribute to increase the risk of getting denture stomatitis, as well as increasing your risk of getting mouth cancer, lung cancer and other problems with your heart and lungs, so I would strongly encourage you to stop, or at least really try to reduce your smoking.

Having diabetes makes you more likely to get it as well and the fungus feeds on sugars from your diet as well, so try to limit your sugar intake in foods and drinks and try to make sure your diabetes is well controlled.

We’ll review you in a week or so to see how things are going. If it’s not made a difference, there are a few other things we can try.

Does that all make sense? Do you have any questions?

What antimicrobial agent would you prescribe to treat this condition?
None or Chlorhexidine
If it doesn’t resolve - 100,000units/ml, 30ml. 1ml after food QDS 7/7.

Can’t prescribe fluconazole or miconazole due to interaction with warfarin

Question 30

Describe how to survey study casts and why it is done

6 mins

Answer 30

Purpose - analyse for undercuts for denture retention/ability to seat crown

Method - place model on plate, ensure plate parallel to base of surveyor. Tighten into position.
Tripod - mark 3 relocation lines
Use analysing rod to check for undercuts
Use graphite marker to draw around gingival margin of saddle areas, ensuring undercuts are marked on teeth too (height/position where undercut starts)
Use measuring tools to measure undercuts (0.25/0.5/0.75mm) to assess what material can be used
If altering PoI, alter cast position/plate orientation and repeat process with red marker

Question 31

Denture design - identify articulator, discuss reciprocation and bracing

6 mins

Answer 31

Articulators - simple hinge, average value, semi-adjustable, fully adjustable

Reciprocation - resists lateral movement of teeth from forces of clasps/retentive components during insertion. Provided by any part of the denture directly opposite a clasp arm (often reciprocal/reciprocating arms)

Bracing - resistance to lateral movements. Horizontal forces are resisted by places rigid components of the denture (bracing components) against suitable vertical surfaces on the teeth and residual ridges

Question 32

Describe how to correct the following faults of F/F dentures

1. Anterior flange missing
2. Midline diastema
3. Underextension at tuberosities
4. Locked occlusion
5. Base plate too thin
6. Tori
7. Tooth position wrong
8. Occlusal table too long (too many posterior teeth over tuberosities)

Give causes and solutions to the following denture problems/faults

9. Problems with fit/impression surface
10. Problems with occlusal surface
11. Problems with polished surface
12. Flabby anterior ridge
13. Atrophic lower ridge

6 mins

Answer 32

1. Remove undercuts, build flange with greenstick and reline. Rebase if not possible or remake if necessary
2. Replica if only problem is teeth (alter at jaw reg for tooth trial). Remake if other problems
3. Reline if functionally good and only problem . Remake if everything bad
4. Remake with replica technique and use cuspless teeth
5. Rebase thicker or Rebase using high impact resin. Or remake
6. Relieve clinically if only problem or ask for tin-foil relief. If too thin or other problems: rebase or remake and ensure lab waxes undercuts
7. Remake
8. Remove posterior teeth/ grind down - or remake
9. Cause: poor impression (lack of post dam, poor adhesion to tray), damage to cast
   Solutions: reline/rebase, remake, add post dam using reline
10. Cause: premature occlusal contact, centric occlusion/relation not coincident, high lower occlusal plane restricting the tongue, locked occlusion
    Solutions: cuspless teeth, selective grinding, re-recording centric occlusion, remake
11. Cause: Overextension, underextended (depth &/or width), not in neutral zone
    Solutions: remove overextension (esp. lingual lower, use pressure indicating paste, allow fraenal relief and flange), add greenstick to underextension and reline, remake if extensive
12. Cause: when hyperplastic soft tissue replaces the alveolar bone
    Solution: perforated trays + light bodied PVS impression (Or special tray with surgical window and take a wash and cut it out + light bodied PVS)
13. Cause: bone resorption
    Solution: admix technique (3 parts imp compound, 7 greenstick)

Question 33

Identify potential faults with a CoCr denture

6 mins

Answer 33

Errors in framework casting: CoCr bubbles making surface rough (air bubbles trapped on wax pattern investing)

Errors in design: too close to gingival margin (impinge on GM when pressure/occlusion), undercuts not blocked out

Faults with prescription between drawing and writing

Support: rests are missing, no posterior stop, rests in wrong places, inadequate rest seat preparation

Retention: wrong clasps, wrong teeth, missing clasps, clasps wrong way

Connector: wrong connector

Indirect retention/bracing/reciprocation - present or absent

Inadequate relief, tooth shade, mould, position, LIMBO

Question 34

Describe how to reline a F/- denture and fill in the lab card

6 mins

Answer 34

Purpose - fit inadequate (under extended, poor support/retention/stability), otherwise fine

Rebase - keep occlusal surface, change fit and polished surfaces.

Method - check occlusion good. Remove undercuts from fit surface, adjust borders with greenstick. Adhesive, light-bodied PVS (reduces risk of increasing OVD - flows into space rather than displacing tissues/denture). Functional imp (bite together), lower imp with opposing denture in situ ± bite reg

Prescription - please pour cast in 100% stone using impression provided. Mount upper to cast and create self-cured PMMA reline to change impression surface. Deliver relined denture on cast

Question 35

List reasons why PMMA dentures # and how to prevent them

6 mins

Answer 35

Causes - thin, under-extended, absent flange, previous repairs, stress concentrators, poor fit, inadequate relief, tooth wear

Prevention - metal framework, alternative denture base (thicker/high-impact acrylic, Flexi-denture), fix causes

Repair - lab can glue together, sometimes new in situ imp required ± opposing dentition/denture. If shattered - remake

Question 36

Design a -/P CoCr denture for the arch provided (photos 14)

Assume that the teeth are of sound prognosis, the dentition is free of care and the oral hygiene is good

6 mins

MOSCE

Answer 36

Kennedy class II mod I. Craddock class III

Support - 34M, 44D, 47M
Retention - 47 occlusal approaching ring clasp. 34 gingivally approaching clasp - mesial (I-bar). 44 gingivally approaching clasp
Connector - lingual bar
Tooth modification - 44 cervical composite, occlusal rests (47 ± 34, 44), guide planes (44D, 47M)

Question 37

Describe how to take primary impressions for F/F dentures and fill in a lab card

6 mins

Answer 37

Edentulous trays - shallower

Imp - alginate (compound if atrophic) ± greenstick

Upper standing 11 o’clock, lower standing 7 o’clock.

Size tray, (± greenstick border moulding/tray modification), adhesive, handle, mix alginate, take imp, remove when set, inspect, disinfect

Lab card - pt details, lab work requested (F/F). Today’s date and time

Next stage - master imps. Date and time of when required

Please pour casts in 50/50 stone/plaster and construct upper and lower special trays in light-cured PMMA with 2mm spacer. Non-perforated with IO handles and finger rests.
Please return trays with casts
Signature

Question 38

You are a GDP. A 59yo female presents C/O pain from 45. Exam and XR reveals the 45 is root treated and has a post-crown. There is evidence of active apical infection.

Discuss the treatment options with the patient.

No further Hx or Ix are needed

6 mins

Answer 38

Introduction - name and designation

Want me to discuss the x-ray with you? XR shows the tooth, with the root down here into the bone. The top of the tooth is a crown and it’s been help in by this post. Underneath the post, the tooth has been root treated. At the end of the root, this black circle here, is evidence of infection. This means that the root treatment is failing and the tooth is compromised and at risk of flaring up and causing an abscess unless we do something about it

There are a few options for you today:

1. Do nothing - if you had no Sx this would maybe be an option, but doing nothing just increases the risk of more pain and the tooth flaring up, causing and abscess and having to be taken out
2. XLA - we take it out today, which will remove the source of infection. It’s cheap, relatively quick to do, although small risk that the tooth might break and we have to cut the gum and remove some bone to help us get it out. However you will lose a tooth and if you didn’t want a gap, would have to fill it with a bridge, a denture or an implant
3. Dismantle post-crown, re-root treat, new post-crown. This would allow you to keep the tooth and remove the source of infection, however it can be quite complex. There’s a risk that it might/might not work and the root/post might #, meaning the tooth is unrestorable. It will also involve multiple fairly lengthy appointments
4. Apicectomy/periradicular surgery - this would involve cutting into the gum, drilling through the bone to the end of the root, before removing the area of infection and then replacing the root filling from the end backwards. They would shorten the root by about 2-3mm and fill it, before stitching the gum back together. You wouldn’t have to remove the post or crown, as long as it is healthy, so reduces the risk of the tooth breaking., however if the problem is coming from the crown or post, it wouldn’t be successful. I would need to refer you to a specialist for this and it might be quite expensive privately or a long wait if it gets accepted by the NHS. However if it works, you get to keep your tooth. There’s a nerve that runs quite close to the tooth that the specialised will have to take care around. If it gets bruised or stretched, there’s a risk that you might have prolonged altered/painful/loss of sensation in your lower lip and chin on the right hand side once the LA wears off.

Does that all make sense? Do you have any questions or any ideas on what you’d like to do?