Restorative Flashcards
1
Q
A 19-year-old patient attends your practise on Monday morning having sustained trauma to teeth 12 and 11 on
Saturday evening. Tooth 12 is completely missing the crown and has a sub-alveolar fracture. Tooth 11 has a pulpal exposure of 2 mm. Both teeth are experiencing sensitivity.
Discuss FOUR steps in the immediate management of tooth 11 (4)
A
- Locate the missing fragment of tooth 12
(a&e if we don’t know where the fragment is) - LA for pain relief and rubber dam
- Exposure = large and >24 hours and tooth is sensitive. Partial Pulpotomy
-Access
-Remove necrotic pulp
-Achieve haemostasis using cotton wool + saline
If we cannot achieve haemostasis full coronal pulpotomy.
If haemostasis is still not achieved- pulpectomy - Restore with CA(OH)2 in pulp. seal with GIC then Composite dentine bandage or definitive composite
2
Q
A 19-year-old patient attends your practise on Monday morning having sustained trauma to teeth 12 and 11 on
Saturday evening. Tooth 12 is completely missing the crown and has a sub-alveolar fracture. Tooth 11 has a pulpal
exposure of 2 mm. Both teeth are experiencing sensitivity.Tooth 12 has a subalveolar fracture and is rendered Unrestorable.
Why is a subalveolar fracture important in
making the tooth Unrestorable? (4)
A
- Lack of coronal tissue to bond to/support restoration/retain restoration,
- Inability to achieve moisture control for restoration,
- Inability to take impression for indirect restoration,
- Hard to establish marginal integrity/difficulty cleaning
- Difficult to gain a suitable seal (leaving the tooth vulnerable to secondary caries)
3
Q
A 19-year-old patient attends your practise on Monday morning having sustained trauma to teeth 12 and 11 on
Saturday evening. Tooth 12 is completely missing the crown and has a sub-alveolar fracture. Tooth 11 has a pulpal
exposure of 2 mm. Both teeth are experiencing sensitivity.
Name TWO alternatives to replace tooth 12 after extraction
A
Implant, Bridge, RPD
4
Q
A new patient attends your practice complaining of pain from tooth 12 and a de-bonded bridge.
What is the likely design of the bridge?
And what types of bridges can you get anteriorly? (1).**
A
Adhesive fixed-fixed bridge (RRB)
- debonded from divergent guidance paths and forces being transmitted down the long axis of 2 teeth
Adhesive cantilever
Conventional spring cantilever for upper incisor teeth
5
Q
A new patient attends your practice complaining of pain from tooth 12 and a de-bonded bridge.
The patient has caries on the palatal of 12. It is sensitive to sweet under the bridge.
What is a reasonable differential diagnosis for the pain from tooth 12? (1)
A
Reversible pulpitis
Discomfort on stimulus (cold/sweet) but this disapears after removal.
Not spontaneous pain.
6
Q
A new patient attends your practice complaining of pain from tooth 12 and a de-bonded bridge.The bridge de-bonded on abutment tooth 12 but not on abutment tooth 21. The de-bonded wing on the 12became a plaque trap leading to caries and ultimately causing pain.
Name a better alternative bridge design for this patient and explain why your design would be better. (2)
A
Adhesive cantilever bridge from tooth 21
less likely to debond as it is only bonded to one tooth - doesn’t have 2 divergent guide paths
If this de-bonded it would fall out (so it wouldn’t become a plaque trap and wouldn’t lead to caries)
This is also less destructive than other bridge designs.
7
Q
Name 4 factors that could cause an adhesive bridge to de-bond (4)
A
- Poor moisture control during cementation
- Unfavourable occlusion,
- Parafunction (bruxism),
- Trauma to front of face,
- Poor quality and surface area of enamel
- bonding to an old composite - needs to be replaced or roughened
8
Q
A new patient attends your practice complaining of pain from tooth 12 and a de-bonded bridge.The bridge de-bonded on abutment tooth 12 but not on abutment tooth 21. The de-bonded wing on the 12
became a plaque trap leading to caries and ultimately causing pain.
How would you treat this tooth 12? (2)
A
Remove caries, Restore with composite, Review
9
Q
A cast with upper Co/Cr framework in placed.
List methods of tooth borne support. (3)
A
Occlusal rests, Cingulum rests, incisal rests
10
Q
A cast with upper Co/Cr framework in placed.
Where should the cobalt chrome denture base extend to?
A
2mm in front of palatine fovea (vibrating line)
11
Q
A cast with upper Co/Cr framework in placed.
There is a rest seat on 12, what is it for?
A
Indirect retention
Rest seats are for indirect retention (located away from saddle area) or bracing- for suport of plates/ clasps/ major connectors.
12
Q
Be able to identify if a clasp is Gingivally approaching or occlusally approaching.
A
13
Q
A cast with upper Co/Cr framework in placed.
Why is the framework not extending to 11 and 23? What is the benefit of this? (1)
A
Less mucosal coverage: easier to clean
14
Q
Two periapical radiographs showing lower anteriors 42, 41, 31 and 32. All treated endodontically with post and
core. You can see radiolucency in all the teeth affected. The patient is referred to you for periradicular surgery.
Three treatment options other than periradicular surgery. (3)
A
Monitor- If they aren’t causing pain/ patient doesn’t want anything done we monitor with radiographs incase radiolucency increases in size.
Extraction-
Re-RCT
15
Q
Two criterias for valid consent. (Given sentences. Have to underline.) (2)
A
Informed, Voluntary, Not Manipulated, Not Coerced, With Capacity
16
Q
To achieve informed consent prior to providing treatment what 6 things should you tell the patient (6)
A
- The treatment and what it involves,
- The risks of the treatment,
- The benefits of the treatment,
- The outcomes of the treatment,
- The risks if they do not undertake the treatment,
- Alternative Tx,
- Cost
17
Q
A patient attends with a fractured 26 MOD amalgam which has also been root treated.
- What are the restorative options for this tooth?
A
- Crown = MCC
- Indirect restoration: inlay, onlay with cuspal coverage
cuspal coverage = gold standard
18
Q
A patient attends with a fractured 26 MOD amalgam which has also been root treated.
The GP has been exposed for 6 months; what is your new treatment plan and why?
A
Re-RCT: Any exposed GP >3 months (to the oral environment (saliva/bacteria) .
The coronal seal has been compromised therefore there can be an ingress of micro-organisms from the oral environment into the root canal system where they can proliferate and cause further infection/PA pathology.
Replace the amalgam with a cuspal coverage restoration (gold standard) to prevent another fracture in the future e.g. onlay, crown
19
Q
A patient attends with a fractured 26 MOD amalgam which has also been root treated.
Features of Nayyar Core. (3)
A
When amalgam is placed into the pulp chamber and 2-3mm into the canal.
- 2-4mm of GP is removed from the canal and replaced with amalgam.
- The undercuts in the divergent canals & pulp chamber provides retention for the amalgam.
- The tooth cannot be prepared for 24 hours until it sets.
20
Q
Name two restorative materials in dentistry that can bond amalgam to tooth. (2)
A
RMGIC
GIC
21
Q
Which bond strength is stronger? Amalgam or composite? (1)
A
Composite
amalgam doesn’t bond it needs mechanical retention
22
Q
Be able to identify the types of tooth wear.
A
Attrition- Wear due to tooth to tooth contact
Location- occlusal and incisal contacting surfaces
Clinically- Facets / flattening of cusps. Flattened incisal edge. Loss of cusp height. Shortened incisors and canine teeth . Restorations show the same wear as the tooth substance.
Abrasion -wear by an abnormal mechanical process independent to occlusion (Habituali.e toothbrushing)
Location - Labial/ buccally/ cervical on canine & premolars
Clinical- V shape or rounded lesion. Sharp margin at the enamel edge where dentine is worn away.
Tongue stud- causing lingual wear.
Erosion - loss of tooth surface caused by chemical process that does not involve bacterial action (extrinsic or intrinisc acid)
Clinically -Early lesions-enamel affected. Loses surface detail & they become flat/smooth/shiny)
Loss of tooth thickness (increased translucency of incisor edges) Bilateral concave lesions-Base of the lesion does not contact opposing tooth (cupping) . Restoration sits proud of tooth (tooth has dissolved away)
Abfraction- Loss of hard tissues from eccentric occlusal forces leading to compressive and tensile stress at the cervical fulcrum areas.
Clinically- V shaped tooth loss where the tooth is under tension. Sharp rim at ACJ.
23
Q
Use the BEWE Score to identify toothwear
A
24
Q
Name 3 routes or ways the tooth could be desensitised? (3)
A
seal and protect- Duraphat Fluoride varnish
desensitizing toothpaste- e.g. colgate sensitive.
Tooth mousse (aids remineralisation)
25
What is the DAHL technique? (1)
A technique used to increase the available interocclusal space. This creates space to allow restorations of the upper anteriors without further tooth reduction.
Composite is added to build up the anterior teeth to the height we want them to be.
Think of this as build ups and an anterior bite plane to prop open the bite and increase OVD.
This leaves a posterior open bite causing the continued eruption of the posterior teeth to fill the gap (restablish occlusion)- we give it about 3-6 months.
.
26
How does the DAHL technique work (2)
* Build up maxillary incisor crowns AND incorporate a composite platform on palatal side of the upper incisors = increase interocclusal space
* allow dentoalveolar compensation (3-6 months) from posteriors over erupting to close posterior open bite
27
List 4 contraindications for use of DAHL appliance. (4)
Absolute contraindications:
* Patients with active periodontal disease
* Short roots
* Post orthodontic treatment
* TMJ problems
* Bisphosphonates- they have slow turnover of bone
* If they have implants
* If they have bridges,
28
You are about to restore the tooth wear with composite. Name 4 constituents of composite and give an example
for each of the constituent. (4)
Resin: bis-GMA,
glass particles: silica or quartz,
Low weight dimethacrylate: TEGDMA,
Light activator: camphorquinone
Silane coupling agent: Gamma-methacryoxypropyltrimothoxysilane
(bifunctional molecule binding resin and filler)
29
Cervical abrasion cavity. Why would you use RMGI instead of composite resin? (2)
* Moisture control
* Less polymerisation shrinkage
* lower modulus which has better flex strength
can also use flowable composite
30
Tooth 11 has a traumatic exposure of the pulp.
What 2 factors would influence your choice of treatment?
Size of exposure (<1mm)
time since exposure (24hrs)
31
Tooth 11 has a traumatic exposure of the pulp.How you would treat this in practice?
In young patients with immature, still developing teeth, it is advantageous to preserve pulp vitality by pulp capping or partial pulpotomy. Also, this treatment is the choice in young patients with completely formed teeth.
●Calcium hydroxide is a suitable material to
be placed on the pulp wound in such
procedures.
In patients with mature apical development, root canal treatment is usually the treatment of choice,
although pulp capping or partial pulpotomy also may be selected.
● If tooth fragment is available, it can be bonded to the tooth.
● Future treatment for the fractured crown may be restoration with other accepted dental restorative material
32
What are the options for replacement of central incisor crown fractured completely off to the root at short notice? (4)
* direct resin bonded bridge with fractured crown as pontic
* Provisional overdenture,
* Provisional post crown
* Vacuum formed splint with tooth
33
Name 3 post materials
* Cast metal (type 4 gold/ stainless steel)
* Ceramics (alumina /zirconia)
* Fibre (Carbon fibre/ glass fibre )
Carbon fibre is avoided in anterior teeth.
34
4 Indications for size of post (4)
* 4-5mm GP remaining
* post <1/3 root width
* post:crown >1:1, at least half of the post length into the subcrestal root,
* 1.5mm of circumferential remaining dentine
35
What may be used to cement the post? (2)
* GI luting cement
* dual cure comp resin luting cement
36
Give 6 methods for removing fractured post
* Ultrasonic vibration,
* Masseran kit,
* cut out for fibre posts,
* Stieglitz/moskito forceps,
* Eggler Post Remover,
* Sliding Hammer
* anthogry
37
What are the clinical signs of erosion? (6)
* Loss of surface detail,
* Surface becomes flat/smooth/shiny
* Typically bilateral concave lesions without a chalky appearance around the edges of caries (Bacterial acid decalcification)
* cupping (preferential dentine wear- base of lesion is not in contact with the opposing tooth.
* Restoration is sitting proud of the tooth.
* translucent incisal edges (due to loss of tooth thickness)
38
What are some causative factors of erosion?
* Extrinsic - diet (carbonated drinks & alcohol), alcohol containing MW, asthma inhaler.
* Intrinsic – GORD, bulimia nervosa, persistent vomiting.
39
How is erosion managed?
Harden up the tooth surface (High fluoride toothpaste/ mouthwash)
Relief of any symptoms (Desensitising toothpaste)
Cover any sensitive/ exposed dentine
Depedent on cause of erosion:
**extrinsic acid- **
Diet modification
Changing habits (Drinking with a straw/ Avoid swilling the drink round your mouth/ careful with sports drinks and gels)
Intrinsic acid
Refer to GP to treat medical cause (Controlling gastric acid- omeprazole/ Anorexia & bolemia )
40
What factors does an implantologist consider before placing an implant?
MH- Any conditions affecting success of treatment e.g. bisphosphonates/ poorly controlled diabetes.
SH- do they smoke? Can they afford treatment?
DH- Pt motivation? Oral hygiene ?
I.O-
Smile line (High Smile line is a greater aesthetic risk)
Periodontal health
Width of edentulous span
Anatomy (Bone height? Bone width? )
Root position of adjacent teeth
Soft tissue adequacy
Gingival biotype-Thin gingivae is more upredictable for aesthetic.
41
When placing an implant- What bone dimensions are required and how are they best measured? (5)
We want 7mm of space in the edentulous area.
The bone dimensions are measured using a CBCT.
Bone dimensions:
Mesiodistally- 1.5mm away from teeth.
Bucopalatally-2mm
Apico-coronal margin- 2mm away from the ACJ.
>5mm space for the papilla between the bone crest and contact point.
2mm away from adjacent structures (IAN/Maxillary sinus)
3mm between inplants (I.5mm mesiodistally of each implant)
42
Give 3 alternative treatment options to implants for a space
1. Accept space 2. RPD 3. Bridge
close space with ortho?
43
How can you check that a bridge has been debonded? (5)
* Probe around the bridge abutments/pontic/wings
* visually inspect - You may see secondary caries or demineralisation
* mobility of the units
* push & check for air bubbles
* floss around the bridge.
44
What factors should be taken into consideration before placing a bridge? (5)
* Abutment teeth
---health (caries/ perio)
--- enamel quality
* Occlusion
----Opposing dentition (contact points/ have the opposing teeth overerupted?)
----Parafunction- e.g. bruxism
* length of span you are replacing (longer= more likely to flex &break)
* OH- can the patient maintain the complex work?
* soft tissue/hard tissue - bridge cannot repalce as well as RPD
45
What alternatives are there to a bridge? (3)
Nothing, RPD, implant, overdenture
46
17-year-old patient presents with congenitally missing 22 and 23.
The patient wants implants, what other treatment options could you advise? (2 marks)
* Removable partial denture,
* Bridge (4 unit, fixed-fixed),
* Orthodontics,
* Combined orthodontics and restorative
47
17-year-old patient presents with congenitally missing 22 and 23.Give a problem relating to aesthetics (1 mark)
Spacing present = unaesthetic
Patient may be being teased due to gap in teeth
Patient may be psychologically affected by missing teeth
low self confidence
48
17-year-old patient presents with congenitally missing 22 and 23.Give a problem relating to function (1 mark)
Patient may have difficulty eating/incising foods
Problems with speech/saying certain words/letters
lack of canine guidance on that side
49
17-year-old patient presents with congenitally missing 22 and 23.The patient wants implants.
Give 3 things a dentist would check (generalised) before referral (3 marks)
MH- Diabete/ Osteoporosis/ Bisphosphonates/ Blood clotting disorder.
DH- Periodontal disease/ Motivation/ Oral hygiene
SH- Smoking/ ability to afford treatment
50
17-year-old patient presents with congenitally missing 22 and 23.The patient wants implants. Give 3 things an implantologist checks (local) (3 marks)
MH- Any conditions affecting success of treatment e.g. bisphosphonates/ poorly controlled diabetes.
SH- do they smoke? Can they afford treatment?
DH- Pt motivation? Oral hygiene ?
I.O-
Smile line (High Smile line is a greater aesthetic risk)
Periodontal health
Width of edentulous span
Bone Quality (Bone height? Bone width? )
Root position of adjacent teeth
Soft tissue adequacy
Gingival biotype-Thin gingivae is more upredictable for aesthetic.
51
What are the signs and symptoms of reversible pulpitis?
* Discomfort when stimulus (Cold/sweet) is applied but goes away after removal. (<30 seconds after)
* Not spontaenous
* Short, sharp pain (Aβ and Aδ fibres, hydrodynamic microleakage stimulation),
52
How is reversible pulpitis managed?
Find out the causative agent & treat (remove caries & restore)
Dietary management (change diet/ habits )
OHI- fluoride toothpaste/ mouthwash/ varnish .
Use desensitising agents if the teeth are sensitive.
53
What are the signs and symptoms of irreversible pulpitis?
* Lingering pain after removal of stimulus
* dull (C fibres)
* spontaneous
* wakened at night
* pain with heat
* poorlylocalised
54
How is irreversible pulpitis managed?
RCT / XLA
55
A patient is referred to have a large MOD amalgam in their 46 replaced as it was causing a Lichenoid Type Reaction. You replace it with composite and take radiograph to ensure there is no secondary caries or pathology.
The patient then attends 5 days later complaining on pain when biting and to transient thermal stimuli.
Give 5 causes of the transient sensitivity to thermal stimuli and pain on biting that they are experiencing (5 marks)
* Deep cavity (without a liner placed)
* Insufficient coolant on prep (damaging the pulp)
* Uncured resin monomer entering the pulp and causing irritation (Soggy bottom due to >2mm curing increments)
* Polymerisation contraction shrinkage- causing gaps below the composite restoration.
---This causes the force to not spread evenly (lots of stress making fracture more likely)
--- Gaps can fill with Dentinal Fluid from the tubules- (allowing bacterial ingress)
* High in occlusion- more pressure as tooth is the first to contact
* Pulpal exposure
* fractured tooth syndrome
* Gingival recession
* Dental abrasion
* Periodontal disease
* Acid erosion - GORD, Dental bleaching, Bruxism,
56
A patient is referred to have a large MOD amalgam in their 46 replaced as it was causing a Lichenoid Type Reaction. You replace it with composite and take radiograph to ensure there is no secondary caries or pathology.
The patient then attends 5 days later complaining on pain when biting and to transient thermal stimuli.
Give 5 restorative management features that could prevent this from occurring (5 marks)
**Occlusion** → check with articulating paper.
**Deep restoration** →
* High speed with water/ slow speed & careful caries removal at pulpal floor- consider excavator for deep caries
* Place lining (CaOH/RMGIC)
**Composite**
* Debonded- use dental dam to prevent moisture contamination & ensure correct bonding procedure
* Polymerisation contraction stress → incremental placement keeping configuration factor low.
* Soggy bottom → <2mm increments and ensure correct curing regime.
**Cracked tooth syndrome**→ difficult to diagnose but can use tooth sleuth. Consider cuspal coverage with an indirect restoration
If fracture caused by **parafunction**= Provide patient with splint- if they have bruxism or toothwear to attempt to protect the restoration.
* Application of duraphat varnish 22600 ppm,
57
How does local anaesthetic work? (2)
This temporarily stops nerve conduction by temporarily blocking voltage gated sodium channels.
Preventing Na+ influx and Action potential generation.
(Action potentials travel along the axon)
58
Name 1 ester and 3 amide local anaesthetics
Ester – benzocaine.
Amide – Lignocaine, articaine, prilocaine, bupivicaine
59
What is in a cartridge of local anaesthetic? (5)
-Base (lidocaine) hydrochloride - anaesthetic agent + aromatic region (Hydrophobic)
-Ester or amide bond
-Amine side chain (hydrophillic)
reducing agent: sodium metabisulfide,
preservative: propylparaban.
fungicide
+/- vasoconstrictor
60
What is the maximum dose of lignocaine?
4.4mg/kg → for most LA it is roughly 1 cartridge/10kg
5.→ 1% = 1g/100ml = 10g/L →
e.g. 2.2ml cartridge of 2% =
2g/100ml = 20g/Lx2.2 = 44mg/ml
Lidocaine w/ adrenaline: 4.4mg/kg (44ml)
Prilocaine w/ felypressin 6.6mg/kg (66ml)
Articaine w/ adrenaline: 5.0mg/kg (72ml)
61
What are the characteristics of an ideal post? (3)
Parallel (more retentive than a tapered post & avoids wedging into the root)
non-threaded - a smooth surface encorporates less stress to the remaining tooth and prevents transmission of occlusal biting force within the root
(Posts with grooves are active therefore there is more force and more stress = greater chance of root fracture)
cement retained- cement acts as a buffer between the masticatory forces and the post/tooth.
62
How can a post be assessed for suitability?
Tooth suitable e.g. molars better w/pulp chamber retention instead –
Length – 4-5mm GP remaining –
Width - <1/3 root
Ferrule – 1.5mm dentine encircling tooth
Bone - >half post length into tooth –
Ratio – crown:root >1:1
63
Give 3 post materials
* fibre e.g. glass fibre, quartz, carbon fibre
* Metal e.g. cast gold, NiCr, stainless steel
* Ceramic e.g. zirconia, alumina
64
Give 3 core materials
* GIC
* composite,
* amalgam
65
Patient comes in with large MOD amalgam that is fractured along with both buccal cusps and has exposed GP.
Give two definitive treatment options (2 marks)
remove the fractured restoration and the fractured cusps and assess remaining healthy tooth tissue;
* Extraction under local anaesthetic
* Indirect restoration - onlay or crown
* Replace restoration-remove MOD amalgam and replace with an MODB amalgam
66
Patient comes in with large MOD amalgam that is fractured along with both buccal cusps and has exposed GP.
Patient says the fracture occurred 6 months ago, how would this change your treatment (2 marks)
Would need to remove the MOD amalgam, remove GP and perform a re-root canal procedure since coronal seal is a key element in prognosis of an RCT'd tooth
then assess restorability and place an indirect restoration for cuspal coverage
67
How would you bond composite to a tooth? Give two dental materials and examples (2 marks)
* Conditioner- acid etch 37% phosphoric acid
Used to: remove the smear layer, roughen the surface and allow micromechanical interlocking
* Primer and adhesive can be separate or together
Combination = prime and bond
use: allows wetting and sealing of the dentine simultaneously
mix of Hema and resin Bis-GMA with a solvent and camphorquinone for light curing.
Can also do 3 steps separately in the total etch dentine bonding agent technique
68
Patient has gold post and core that has debonded several times.
3 reasons why it has debonded (3 marks)
* Post fracture
* Core fracture
* Root fracture at post level when not attributed to trauma (stress release)
* Untreatable caries
* Traumatic fracture
* Furcation perforation (due to dentine pins),
- Parafunctional habits
- post size too small
- inadequate use of cement
- poor quality cement
69
Patient has gold post and core that has debonded several times.Fracture occurs at the junction of the post and core, give 3 reasons why? (3 marks)
* excessive lateral forces from clenching and grinding- Causing Traumatic fracture (e.g. stress/ bruxism )
* inadequate ferrule/solid tooth tissue for crown margin to be placed on (increased likely hood of fracture)
* Short/narrow/overtapered post
* Inadequate moisture control when bonding (Causing contamination).
* Bacterial interaction causing caries and thus decay of the tooth resulting in fracture.
70
What are the principles of cavity preparation?
1. Identify and remove carious enamel
2. Remove enamel to identify the maximal extent of the lesion at the amelodentinal junction
3. Remove peripheral caries in dentine starting from the outside in.
4. Only then remove deep caries over pulp
5. Outline form modification:
Enamel finishing (removal of CSM)
Occlusion- ensure the occlusion is not over the CSM.
Requirements of the restorative material (Composite- remove any enamel overhangs. Amalgam cut the retentive shape. )
6. Internal design modification: Internal line and point angles, Requirements of the restorative material (Composite- smooth internal anatomy. Amalgam-undercuts)
71
What is the hybrid layer?
A layer of dentine consisting of collagen and resin.
This is created by the prime and bond which bonds dentine to the resin. (Interface between dentine and the restorative material)
***
1. The dentine is etched to remove the smear layer & open the dentinal tubules to expose the collagen layer.
2. The primer is hydrophilic at one end to bond to the wet dentine surface & hydrophobic at the other end to bond to the resin.
3. The resin penetrates the primed dentine (now hydrophobic) and forms a bond within the tubules & exposed collagen fibres- Forming the hybrid layer.
72
What are the different types of dentine and how do they affect bonding? (3)
Primary dentine laid down during development – open tubules and good for bonding.
Secondary dentine laid down during function. Ok for bond.
Tertiary dentine – Reactionary and is laid down due to mild stimuli and reparative due to intense stimuli. This has Poor bonding ability due to poorly organised tubules or sclerosed tubules.
73
What is the inorganic content percentage of dentine?
Calcium hydroxyapatite (70%)
74
Give three constituents of GP other than GP (4)
* zinc oxide - 65%
* radio-pacifiers - 10%
* plasticisers - 5%
* waxes.
75
Give the function of a sealer (3)
To fill the space between the GP & the root canal wall to provide a fluid tight seal
fills voids and irregularities
lubricates
76
Give 3 common sealers used
* epoxy resin (AH26 plus)
* Calcium hydroxide,
* ZOE
* calcium silicate
77
How do you assess obturation on a radiograph? (5)
* Check correct length within 2mm of radiographic apex
* Well compacted. (check density)
* All canals filled with GP and sealer
* tapered, cone shaped and continuously funnelling
* GP stopped at ACJ(anteriors) and orifice (posteriors)
no excess GP in pulp chamber
78
You are endodontically treating tooth 16 for a 49 year old patient. The root canal system, which includes the MB2
canal, has been prepared over two visits. On the third you plan to obturate the tooth.
Why do we obturate? (3)
* Provides a coronal and apical seal (as well as sealing the dentinal tubules & accessory canals)
* Entomb (seal) remaining bacteria
* prevent ingress of fluid and microorganisms into the canal system = prevent reinfection
79
Give 4 methods of Obturation
* Cold lateral compaction
* thermafill (carrier based obturation)
* warm vertical compaction
* thermoplastic injection
80
What percentage of maxillary first molars have an MB2 canal?
93%
81
What are the 3 principles of canal preparation?
(design objectives of endodontics?)
* Continuously tapering funnel shape,
* keep apical foramen as small as possible,
* maintain apical foramen position.
82
What are the advantages of the crown down technique for endodontic treatment ? (5)
* Removes bulk of infected tissue,
* reservoir for irrigant,
* keeps reference point for WL,
* makes straight line access easier,
* reduces risk of extrusion of infected material at apical foramen
**Crown down prepares coronal third first commonly used for Rotary files such as reciproc **
83
Give 6 rules for locating orifices in the pulpal floor?
The Law of Symmetry 1:
(With the exception to maxillary molars) the orifices are equidistant from a line drawn in a mesial-distal direction through the pulp chamber floor
The Law of Symmetry 2:
(With the exception to maxillary molars) the orifices lie on a line perpendicular to a line drawn in a mesial-distal direction across the centre of the floor of the pup chamber.
The Law of Colour Change:
The colour of the pulp chamber floor is always darker than the walls.
The Law of Orifice Location 1:
The orifices of the root canals are away located at the junction of the walls and the floor.
The Law of Orifice Location 2:
The orifices of the root canals are away located at the angles of the floor-wall junction.
The Law of Orifice Location 3:
The orifices of the root canals are away located at the terminus of the root developmental fusion lines.
1. Law of colour – always darker
2. law of symmetry 1 – orifices lie equidistant from MD line through chamber (except max.molars)
3. law of symmetry 2 – orifices lie perpendicular on MD line (except max.molars)
4. Always at junction of floor and wall
5. Always at angle in floor and wall junction
6. Always at terminus of developmental fusion lines.
84
Give 4 reasons for irrigation during endodontic treatment? (7)
1. Mechanical preparation alone does not remove all bacteria.
2. Reaches areas files cannot get to.
3. Flush out debris and prevents packing
4. Organic and non-organic content is dissolved
5. Remove smear layer (pulpal material and inorganic debris)
6. Lubrication of the file
7. It cools the file & tooth when using ultrasonic energy
85
Why is sodium hypochlorite a good irrigant? (3)
* Has potent antimicrobial activity
* Dissolves pulp remnants, collagen and necrotic
* Disrupts the smear layer by acting on the organic component.
86
What strength of NaOCl is used?
3% in GDH (Between 0.5-6% in practice)
87
Apart from NaOCl name another common irrigant used? (2)
Chlorohexidine Digluconate - 0.2%
*reacts with NaOCl producing parachloranaline which is cargiogenic*
EDTA- 17% makes it more susceptible to NaOCl but these cannot interact.
88
How is the smear layer removed?
Joint use of EDTA and sodium hypohlorite
EDTA Ethylenediaminetetraacetic Acid (17%) & NaOCl (3%)
EDTA opens dentinal tubules making dentine more susceptible to NaOCl for irrigation.
89
Name 2 intracanal medicaments and state their use
Ledermix → corticosteroid and antobiotic tetracycline paste. Management of vital ‘hot pulps’ (reducing pulpal inflammation) which cannot be anaesthetised
Works for 5-7 days.
Non-setting CaOH→ Antibacterial as pH 12.5.
Useful in abscess present/previously treated teeth
Removes tissue debris
Works for 7 days but may weaken root if left too long.
This affects hydrolysis of the lippopolysaccharides to reduce inflammatory potential.
90
A middle-aged gentleman attended your surgery with the metal ceramic crown from his upper right central incisor in his hand. He has no pain. You notice that the dentine core has fractured off inside the crown. There is no history of previous root canal therapy.
1 What four features of the remaining tooth tissue of the central incisor might indicate whether it can be successfully restored or not? (4 marks)
Quality of tooth tissue present
Height of remaining tooth tissue
Mobility of the tooth
Periodontal status
Pulpal disease
Crown:root ratio ( 2:3 ideal -minimum 1:1)
Fracture- is it involving the pulp?
91
Pt presents with MCC in hand from upper central. Give 3 short term options to replace tooth and explain (6)
* Re-cement failed MCC as a temporary crown - protects remaining tooth structure while new crown is produced.
* Make a provisional crown (Protemp bis-acrylic composite resin) and use a temporary cement (non-eugenol temporary cement).
* Adhesive cantilever temporary bridge.
* Preformed anterior provisional crown
92
Radiograph PA of 37 with caries and impacted 38
3 pathological/ iatrogenic features in radiograph (3)
* Overhangs,
* Fractured endo file,
* Radiolucency,
* Bone defect,
93
Radiograph PA of 37 with caries and impacted 38.
Dull throbbing pain in region, differential diagnosis for what could be keeping patient up at night (3)
Irreversible pulpitis,
Pericoronitis,
TMD
94
Radiograph PA of 37 with caries and impacted 38.
Management options for 37 and 38 (4)
37:
XLA, RCT
38:
XLA (+/- surgical)
Coronectomy
95
Missing upper laterals - Type of bridge you can use to replace teeth (1)
Mesial cantilever resin bonded bridge
spring cantilever - historic
Fixed fixed - in C2D1 and AOBs where anterior teeth not in occlsuion
96
Missing upper laterals - Abutment teeth to be used (2)
Permanent canine, Central incisor
97
4 pieces of information needed from the patient for technician to make bridge (5)
Bridge design
Master impressions,
Bite registration
Shade and mould
facebow
98
Apart from a bridge give alternatives for replacing missing upper laterals
Removable partial denture
Implant
99
How does the clinical presentation of caries compare to a radiograph?
Caries deeper clinically.
100
What are the indications for a resin retained bridge? (6)
* Young teeth
* Good enamel quality (unrestored tooth)
* Large abutment tooth surface area. (larger area=more bonding area= more retentive)
* Minimal occlusal load.
* Good for single tooth replacement.
* To simplify a partial denture design (Filling up one or two edentulous spaces would simplify as you would no longer need a rest seat/clasp somewhere)
101
What are the contra-indications for a resin retained bridge? (6)
* Insufficient or poor quality enamel
* Long span needed
* Excess soft or hard tissue loss
* Heavily occlusal force (e.g. bruxist)
* Poorly aligned/tilted/spaced teeth
* perio involved abutment.
102
What is the shortened dental arch?
The idea that a minimum of 20 teeth are needed in the arch for acceptable mastigatory function/maintenance of oral hygiene and aesthetics.
There needs to be 3 to 5 occlusal units remaining
Pair of occluding premolars = 1 unit
Pair of occluding molars = 2 unitss.
103
Why is the shortened dental arch considered acceptable?
This provides patient with suitable aesthetics, function, occlusal & mandibular stability and ability to maintain oral hygiene.
104
What are the indications for a shortened dental arch?
(whats a good candidate) (6)
* Missing posteriors teeth with 3-5 occlusal units remaining
- 1 point for occluding premolars
- 2 points for occluding molars
A good candidate-
*A pair of occluding molars (2 points)
*a pair of occluding premolars (1 point)
* Sufficient occlusal contacts to provide a large enough occlusal table;.
* good prognosis of remaining teeth,
* Pt not motivated to pursue complex treatment plan for a prosthesis. (irregular attender)
* patient good OH
* limited resources (no pros lab)
* financial implications
105
What are the contra-indications of a shortened dental arch?
* TMD,
* poor prognosis of remaining teeth,
* periodontal disease,
* pathological tooth wear,
* Severe class II or class III malocclusion. (We need the occluding teeth
106
How can a shortened dental arch be extended? (4)
* RRB,
* Conventional bridge
* implant,
* RPD
107
What are the 5 requirements of occlusal stability?
* Stable and even contacts on all teeth in ICP.
* Anterior guidance in harmony with the envelope of function (canine guidance = only canine in contact)
* protrusion = All posterior teeth disclude and anteriors in contact
* non-working side = All posterior teeth on the non-working side disclude during mandibular lateral excursion. (opposite side to the direct the mandible is travelling in)
* Working side = All posterior teeth on the working side disclude during mandibular lateral exursion. (same side as direction mandible is travelling in)
dynamic occlusion:
o Canine guidance
o Posterior disclusion in lateral excursions
o No non-working / working side contacts
o No protrusive interferences
static occlusion:
o stable contacts in ICP
| Don't want posterior contact- not designed to absorb lateral force.
108
What are the signs of occlusal trauma? (10)
Frequent fracture of restorations or teeth.
Progressive tooth mobility/fremitus
occlusal discrepancies - non-working side contacts and premature contacts
tooth migration
widened PDL
Wear facets
Thermal sensitivity
root resoprtion
Dental pain not explained by infections
Soft tissue- Tongue scalloping. Pronounced linea alba
Contributing factors to TMD
109
Name 4 types of tooth wear and describe their appearance
**Attrition** – Tooth-tooth contact. Incisal edges and flat occlusal planes, loss of clinical crown height, restorations wear at same time.
**Erosion** – Chemical wear with non-bacterial acid. Intrinsic v Extrinsic. Surface detail lost, smooth/polished
appearance, restorations stand proud, cupping, usually palatal uppers and occlusal surface lowers.
**Abrasion** – Repeated foreign object wear e.g. tooth brushing, habits. wear usually on canines and premolars and presents as notching or v shaped cervical lesions.
**Abfraction** – Wear from eccentric occlusal loads seen away from point of load. Cervical wear/cracks.
110
How may tooth wear be monitored? (4)
BEWE index, Smith and Knight, photos, study models.
111
What percentage of adults have tooth wear?
60%
77% ??
112
Give 4 intrinsic and 4 extrinsic causes of tooth discolouration
Intrinsic → fluorosis, tetracycline, amelogenesis imperfecta, dentinogenesis imperfecta, loss of vitality, restorative
materials.
Extrinsic→ smoking, dietary (tannins from coffee and tea), chromogenic bacteria, Chlorohexidine
113
How does vital bleaching with hydrogen peroxide work?
Discolouration is caused by the formation of chemically stable, chromogenic products within the tooth substance which are long chain organic molecules.
HO2- a free radical oxidising agent produced whe carbamide peroxide is broken down.
HO2 causing the oxidisation of the long chain compounds. Which:
Reduces the molecular size & often pigmentation of the molecules.
Causes ionic exchange in the metallic molecules leading to a much lighter colour
114
What is the common active ingredient in tooth whitening bleach?
Active ingredient = hydrogen peroxide
Carbamide peroxide Breaks down to form hydrogen peroxide and urea.
common concentrations = 10% carbamide peroxide and 3.6% hydrogen peroxide
Maximum concentration = 16.7% carbamide peroxide equivalent to 6% H202
115
Give 4 risks of vital bleaching
* Sensitivity (60% pts normally only temporary)
* Wearing off- oxidised chromogens reduce over time requiring retreatment every 1-3 years.
* Soft tissue irritation- dependent on concentration.
* Restorations- Teeth bleach but composite won't (may need fillings replaced to match & continued bleaching)
* May not work
* Patient has to comply with regime.
* Pt could be allergic
116
A pt presents with a discoloured anterior tooth. It is not sensitive or symptomatic but he reports he sustained a blow to it a couple of years ago and the discoloration is getting worse. How would you go about finding the aetiology of the discoloration.
* Through history regarding the trauma. (Cause/ any pain at the time/ When did the colour change start)
* Sensibility testing (including adjacent teeth)
* Type of discolouration (Pink -burst blood vessel/ Brown + Black +Grey- non vital)
* Take radiographs
* Compare with any previous clinical photographs.
117
pt presents with a discoloured anterior tooth. It is not sensitive or symptomatic but he reports he sustained a
blow to it a couple of years ago and the discoloration is getting worse.
What special investigations would you undertake?
Periapical radiograph. Sensibility test including adjacent teeth.
118
Patient has a discoloured tooth anteriorly but it isn’t sensitive or symptomatic; patient sustained a blow to it a couple of years prior and discolouration is getting worse.
What treatment options are there for discolouration? (5)
Accept and monitor
composite or porcelain veneer
microabrasion
vital external bleaching
non-vital bleaching
119
List 4 design/preparation features that may have led to conventional bridge failure
Poor abutment health,
Over-tapered prep- more paths of insertion and removal
unfavourable occlusion/parafunction,
poor crown:root ratio,
Too long a span- increased risk of flex & fracture.
*No common path of insertion (fixed fixed conventional)
*debonded gone unnoticed (fixed fixed adhesive)
120
A pt with a conventional bridge with retainers on 11 and 22 and a pontic of 21 complains it is loose. You suspect
the retainer on 22 has debonded. Give 2 alternatives for replacing the tooth
RPD, implant
121
A pt with a conventional bridge with retainers on 11 and 22 and a pontic of 21 complains it is loose. You suspect the retainer on 22 has debonded.
Give 2 alternative bridge designs for this scenario (a resin retained bridge is not an option as the adjacent teeth are prepped)
Conventional Cantilever Bridge (one retainer)
Spring cantilever- pontic attached to a metal arm that runs across the palate.
122
A 25-year-old male patient attends with irreversible pulpitis involving tooth 36 and requires root canal treatment. The patient is healthy and not on any medication. Radiographic findings reveal root canal curvature of the mesial roots of about 20 degrees.
List four problems that can occur when instrumenting a tooth with curved roots using only stainless steel ISO hand files. Give reasons for each of the problems.
(2020 Q1A)
Ledges- Occur when working short of the length & these are difficult to bypass.
Perforations-- Less flexibility so could cut in a straight line rather than negotiating the curve.
Blockages-Caused by dentine debris getting packed into the apical portion of the root- this could cause a false canal being cut/ perforation/ transportation of the apex.
Fractured instruments- Instrument locking in too narrow an area (torsional stress), If instrument binds (Torsional fatigue- some parts are bound and some are not causing the file to twist)
Zipping- Occurs as a result of the tendency of the instrument to straighten inside the curved canal. This results in over-enlargement, under preparation, transportation of the foramen & ultimately a tear dropped shaped canal.
123
A 25-year-old male patient attends with irreversible pulpitis involving tooth 36 and requires root canal treatment. The patient is healthy and not on any medication. Radiographic findings reveal root canal curvature of the mesial roots of about 20 degrees.
Describe the process of canal shaping and cleansing (not obturation) using ProTaper Universal instrumentation of root canals. Assume that straight line access has been achieved and working length has been determined with a size 10 stainless steel hand file. Your apical finishing size should be 0.25mm. (6 marks)
| 2020 Paper A Q1
1. Size 15 ISO file to 2/3 of EWL.
2. Irrigate to remove any debris.
3. S1 file to 2/3 of WL to create coronal flare.
4. Size 10 ISO file to establish apex & Apex locator.
5. S1 file with balanced force to CWL (Recapitulate with ISO 10 and irrigate)
6. Bring iso 10 to EWL
7. Use S1 to patency file.
8. S2 taken to CWL by balanced force. (Irrigate and recapitulate with ISO 10)
9. F1 to CWL to achieve the apical diameter
10. Apical gauge- using corresponding K file to F1 file.
11. Use F2 to CWL to achieve the apical diameter (0.25mm)
12. Apical gauge with corresponding K file
13. Manual dynamic irrigation
a. 3% NaOCl for 10 minutes
b. GP or an endoactivator to irritate the sodium hypochlorite
c. Aspirate canal and dry with paper points
d. EDTA for 1 minute
e. Rinse
f. Final rinse with NaOCl
g. Dry with paper points.
124
What are the landmarks for an inferior alveolar nerve block?
Pterygomandibular raphe, coronoid notch and posterior border of ramus, contralateral premolars → insert needle to
pterygomandibular space until you contact bone then retract.
125
Name 2 alternative techniques to an inferior alveolar dental nerve block
Akinosi Block technique:
Used for patients with severe trismus (they are unable to open their mouth)
1. Pull cheek away
2. Needle moves in parallel to the floor just above the gingival margin of the upper molars.
3. Keep inserting the needle until the barrel end is in line with the 7 and 8s.
4. Inject
Gow Gate technique:
(requires px to open wide)
Injection site - anterior to the neck of the condyle in proximity to the mandibular branch of the trigeminal nerve after its exit from the foramen ovale.
Dangerous if you don’t get it right.
126
How do you manage a patient if you accidentally inject into the parotid gland?
Explain situation to patient, provide eye protection, advise length of paralysis as long as LA, RV.
127
Give 3 reasons for instrumentation of root canals
1. Remove infected soft and hard tissue to allow irrigant access to apical canal space.
3. Make space for medicaments and obturation.
4. Create an environment for periradicular healing (retaining integrity of radiuclar structures)
128
What advantages do protaper have over K-files? (6)
Shape memory
Superelasticity
Decreased lateral pressure so decreased risk of ledge, zip etc.
Decreased number of instruments needed,
increased cutting efficiency
Increased flexibility in larger sizes and tapers .
129
Name a rotary endo system
Reciproc.
ProTaper Gold
130
Filing and reaming are 2 envelopes of motion for files. Describe 2 others
Watch Winding:
Back and forward oscillation (same degree of movement forwards and backwards) with Light apical pressure = 30-60°.
Balanced Force:
Turn clockwise (i.e.) 90 degrees
Apply firm apical pressure to break the dentine
Turn anticlockwise > 90 degrees
= range from 60-120°.
131
Name 3 reasons a file may separate
1. Flexural stress (repeated cyclic fatigue).
2. Torsional stress (binding to canal wall)
3. Complicated curved canal/non-straight line access
132
Drawn and Label posselt's envelope
RCP (retruded contact position) = the first tooth contact where mandible in the retruded axis position
ICP (intercuspal position) = maximum interdigitation of teeth which is comfortable
E (edge to edge) = Translational movement when teeth slide from ICP guided by the palatal surface of the upper incisors
PR (protrusion) = condyle slides downward and forwards along the articular eminence
T (max opening) = full translation of the condyle over the articular eminence
R (retruded axis position) = where the condyle is in the most superior and anterior position in the glenoid fossa
133
What is RCP and what is its importance?
The contact in centric relation, this is when the first contact of teeth/denture occurs when condyles are in their most superior position in the mandibular fossa/mandible in the retuded axis position.
This is useful as it is the most reproducible position (for registration in complete dentures)
134
What is Hanau’s Quint?
Used for setting teeth - These are the 5 factors that affect an occlusally balanced articulation.
* Occlusal plane inclination,
* incisal guidance angle
* sagittal condylar guidance angle,
* cuspal height
* compensating curves.
135
What is the thickness of shimstock?
8 microns used with mosquito forceps
136
What is the average supracrestal attachment ?
Distance between the junctional epithelium and the supracrestal connective tissue (it should be 2mm)
Approx.2mm from alveolar crest to sulcus of gingiva.
137
A patient has a large #MOD amalgam and exposed GP from RCT.
Give 2 definitive Rx options
if exposed more than 3/12 = XLA and re-RCT
Replace MOD with onlay or crown +/- post/core
138
An amalgam has an overhang on its mesial surface. How could this have been avoided?
Correct adaptation of matrix. Wedge. Adequate condensing of amalgam.
139
What problems may occur due to this overhang?
Plaque trap and food packing, therefore, 2° caries and gingivitis and periodontal disease.
May also lead to a # amalgam if in thin section.
140
How do you manage an amalgam overhang?
Replace → remove all and place new, better contoured amalgam.
Repair → if possible adjust overhang.
141
Give 4 functions of a facebow
Mounting the upper cast only
USES: indirect retsorations (crown, onlay, bridges) and fixed pros
Replicates the relationship between the maxilla and the terminal hinge axis of the mandible on the articulator . (Terminal hinge axis is where the head of the condyle is in the most superior position in the glenoid fossa)
Establishes the relationship of the maxillary dentition to the horizontal reference plane so that the mandibular cast can be mounted on an articulator in the correct anatomical position in ICP (using interocclusal bite registration)
142
Name 4 types of articulator
Simple hinge, average value, semi-adjustable, fully adjustable.
143
Give 3 reasons anterior tooth guidance is preferred?
mutually protected??
1. canines are designed to withstand/absorb significant lateral forces
2. Protect teeth and restorations on posterior.
3. Allow muscles to rest (less muscular activity due to the gap made between the posterior teeth )
4. avoid trauma & undesirable tooth movements
144
What are the 6 principles of crown preparation?
1. Preserve tooth structure.
Overpreparation weakens the tooth and can damage the pulp.
2. Retention and resistance form.
Retention-
preventing removal by limiting the number of paths of insertion.Taper the walls at 6 degrees.
Resistance-
To prevent dislodgement of restoration by forces in the apiacl or oblique direction. We want longer walls. (crown has longer to slide before it is dislodged)
3. Structural durability.
The restoration must contain a bulk of material that can withstand the forces of occlusion (the prep needs to allow this )by: Occlusal reduction/ bevelling the functional cusp/ axial reduction.
4. Marginal integrity.
Prepare finish line configurations to accomodate robust margins with close adaption to minimise microleakage (chamfer or shoulder finish)
5. Preserve periodontium
Margins should be smooth & fully exposed to cleansing action. Placed so the dentist can finish them and the patient can clean them. Placed at the gingival margin if possible (not impinging on the supracrestal attachment)
6. Aesthetics- Consider which material is the best aesthetic/ least destructive prep/ least destructive to opposing teeth.
145
What are the stages of crown preparation?
1. Occlusal reduction
Depth cuts using short fissure bur & join them. We want to cut at angles for posterior teeth to keep some of the occlusal morphology.
3. Separation- Using a separating bur to remove the contacts with the adjacent teeth.
4. Buccal & lingual reduction - 2 plane reduction using a fissure bur. Follow the curvature of the buccal surface (avoid buccal pulp horn) Blend these reductions using a chamfer bur.
5. Finishing.
Using shoulder or chamfer burs
6. Check occlusal surface and clearance- There should be sufficent occlusal clearance to fit the restoration. .
146
give the crown reductions for an all metal crown
Occlusal reduction: all 2.0mm
All metal crown – Ax 0.5mm, chamfer (0.5mm)
occlusal reduction- 1.5mm functional cusp 0.5mm non-functional
Axial reductino- 0.5mm. Chamfer 0.5mm
147
give the crown reductions for an MCC
Occlusal reduction: all 2.0mm
buccal shoulder (1.5mm), palatal chamfer (0.5mm)
Occlusal reduction 1.8mm
Axial reduction 1.3
Buccal shoulder 1.3, palatal chamfer 0.5
148
Give the crown reduction for an all ceramic
Occlusal reduction: all 2.0mm
Axial reduction 1.5mm
Margin- 1.0-1.5mm
149
Name 1 advantage to placing a crown as a posterior restoration .
A crown reinforces and strengthens the tooth underneath more than a posterior restoration.
The restorations don't offer as much protection and can cause fracturing of the tooth tissue that is left due to configuration factors of pressure.
provides cuspal coverage which:
- Provides a coronal seal
- Prevents microbial ingress
- Prevents catastrophic fracture
- Strengthens and reinforces the remaining tooth structure
- Ensures occlusal forces are transmitted evenly down the long axis of the tooth
- Ensures that there are no margins on the occlusal interface
150
Describe the endodontic process including calculating working length until the obturation stage.
1. Expose the pulp chamber using a Flat fissure.
2. Open the full extent of the pulp chamber with an Endo Z bur.
3. Identify the pulp canal orifices using a DD16 probe.
4. EWL should be calculated using a pre-op radiograph.
**Preparation- Protaper technique**
Use #10 K file at 2/3 of WL.
Create a coronal flare- Place S1 at 2/3 of WL
Calculate corrected WL using Apex locator.
Create glide path-
Coronal flare with S1 2/3
Use #10 K file with WW to establish apex.
Irrigate & repeat using size 15 (ww) and size 20 (bf)
S1 with Bf to EWL (use file 3 times before irrigating & recapitulating)
Bring #10 K file to EWL
Use S1 to patency file.
S2 taken to CWL by bf
Flood chamber with irrigant
Prepare the apical diameter
Take F1 to WL
(Apical diameter should be 2 sizes bigger than the F file that initially binds)
Apical gauging
-Advance the K file and it should not go any deeper.
(If k file is still loose move onto next F file - apical gauge again)
10 minutes of sodium hypochlorite (manual dynamic irrigation using a paper point)
1 minute of EDTA
End with sodium hypochlorite.
Obturate the root canal system with GP size matched cones & sealer.
Use the super ended alpha to sever the end of the GP cones. clean the cavity & place vitrebond for a coronal seal.
Then final restoration.
151
A patient attends with a space between 13 and 14
- What investigations should you do and why? (5)
Assess perio status as this can cause drifting of teeth:
o BPE – screening tool for periodontal health status
o PGI – to assess plaque and bleeding levels with BPE >1
o 6 point pocket chart – to assess periodontal disease, true pocketing, gingival recession and mobility when BPE scores >3
o (Periapical) radiographs to assess bone levels in perio, prognosis of the teeth, any radiolucencies e.g. cysts which can cause displacement of teeth
o Study models to monitor change over time
152
A patient attends with a space between 13 and 14
- Other than aesthetics, why would restoring this space be challenging?
o The space is relatively small and if the teeth are of good prognosis you would be reluctant to remove healthy tooth tissue and place veneers or crowns.
- Composite could be used to make either the 13 or 14 bigger to help close the gap but this may be noticeable.
153
A patient attends with a space between 13 and 14
What problems are associated with implant placement in this case? (3)
Inadequate space available – requires 7mm between each teeth (M-D)
Inadequate bone quality and quantity due to periodontal disease
Current uncontrolled periodontal disease
154
What are the advantages of non vital bleaching? (5)
Simple technique
Tooth conserving
Original tooth morphology remains
Gingival tissues are not irritated by bleaching (side effect of the gum-guard of for vital bleaching)
No lab assistance needed for the walking bleach technique.
155
What are the disadvantages of the non-vital bleaching technique. (5)
* Risk of External cervical resorption
* Risk of spillage of the bleaching agent
* Risk of failure to bleach the tooth
* Can overbleach the tooth
* Can cause brittleness of the crown.
156
Describe the combination inside outside technique
Access cavity of the tooth is left open and a custom mouthguard created. (you can cut out windows in the guard for any teeth you don't want to bleach)
Patient applies bleaching agent (10% carbamide peroxide) to the back of the tooth and tray.
The tray should be worn at all times except eating and cleaning.
Gel. ischanged every 2 hours except at night.
Access cavity needs to be kept clean (replacing gel/ remove food debris etc.)
When restoring the pulp chamber after
NSCaOH for 2 weeks sealed in with GIC to prevent external resorption
After 2 weeks
Restore with White Gp. &composite (allows rebleaching)
Incrementally cured composite (no rebleaching but a stronger tooth)
157
You are treatment planning a patient for a shortened dental arch.
The patient has 2 occluding premolars and 1 pair of occluding molars.
How many occlusal units does this patient have?
2 pairs of occluding premolars = 2 units
1 pair occluding molars = 2 units
so patient has 4 occluding units
158
What skeletal classes are contraindicated iwth a shortened dental arch and why?
In severe class II or class III malocclusions.
For a shortened dental arch we want the anterior teeth to be occluding- they won't be in these severe malocclusions?
159
Give 3 reasons why periodontal disease is a contraindication for a shortened dental arch? (4)
More occlusal load on the limited teeth -could cause drifting of the periodontally compromised teeth
poor prognosis = chance of loss and compromise SDA???
Teeth are mobile = reduce the functional capacity of the few remaining teeth
160
Discuss the 5 and 10 year survival rate for a Resin retained bridge
80.8% 5 year survival
80.4% 10 year survival
161
Susan is a 29 year old patient who is a regular attendee at your practice, she has previously undergone periodontal treatment, she attends as an emergency complaining of pain in her upper front tooth. On examination you notice a swelling pertaining to the 11, TTP and there is associated lymphadenopathy.
- Give 2 differential diagnoses for what this condition could be
Periodontal abscess - if lateral TTP
Periapical abscess
Perio-endo lesion
162
Susan is a 29 year old patient who is a regular attendee at your practice, she has previously undergone periodontal treatment, she attends as an emergency complaining of pain in her upper front tooth. On examination you notice a swelling pertaining to the 11, TTP and there is associated lymphadenopathy
Give 2 special investigations you would undertake to confirm your diagnosis.
Sensibility testing - EPT & Ethyl chloride (non-vital tooth in periapical abscess/ vital in periodontal abscess)
Radiography- Looking for periapical radiolucency.
pocket charts (6ppc) - are there deep pockets associated
163
Mrs Dodds is a 45 year old women who has a large MOD composite on 46 6 months ago. She presents complaining that a bit of filling has come away and she is not happy. You suspect that this may have something to do with bonding and placement of composite. She is adamant she wants a crown and heard that porcelain is the best and demands this,
- Name 1 advantage of placing a crown as a posteiror restoration.
A crown reinforces and strengthens the tooth underneath more than a posteiror restoration.
The restorations do not offer as much protection (crown has full cuspal coverage) so there is a risk of fracturing the tooth due to the configuration factors of pressure.
provides cuspal coverage which:
- Provides a coronal seal
- Prevents microbial ingress
- Prevents catastrophic fracture
- Strengthens and reinforces the remaining tooth structure
- Ensures occlusal forces are transmitted evenly down the long axis of the tooth
- Ensures that there are no margins on the occlusal interface
164
Endo on 16 for 49 year old patient. Root canal system has been prepared over 2 visits (including Mesio-palatal canal). On 3rd visit you plan to obturate.
What 3 criteria must be fulfilled before obturation? (3)
Tooth must be asymptomatic
Full chemomechanical preparation of all canals - instrumentation and irrigation protocol
Canal must be fully dried.
165
Endo on 16 for 49 year old patient. Root canal system has been prepared over 2 visits (including Mesio-palatal canal). On 3rd visit you plan to obturate.
What is the functionof root sealer when used with GP cones
To seal the space between the GP and the wall.
It fills voids and irregularities in the canal/ lateral canals and between GP points used in lateral condensation
As a lubricant during obturation.
166
Endo on 16 for 49 year old patient. Root canal system has been prepared over 2 visits (including Mesio-palatal canal). On 3rd visit you plan to obturate.
Give 3 generic types of sealer commonly used for obturation.
Epoxy resin sealer (AH26 plus)
Zinc oxide eugenol
Bioceramic sealer (calcium silicate and calcium phosphate)
Calcium hydroxide (dycal)
167
Endo on 16 for 49 year old patient. Root canal system has been prepared over 2 visits (including Mesio-palatal canal). On 3rd visit you plan to obturate.
Why. dowe obturate
To prevent bacterial ingress along the canal- to prevent microbial re-infection.
To seal any remaining bacteria in.
To provide a coronal and apical seal on the rc.
168
Patient arrives with MCC from tooth 11, the dentine core has fractured off inside the crown. The retained root is restorable and the patient has requested a new crown is made.
**- What 2 temporary restorations can be used for 11 during the endo?**
GIC
ZOE
Cavitt
Provisional over denture
Provisional post-core crown.
169
Patient arrives with MCC from tooth 11, the dentine core has fractured off inside the crown. The retained root is restorable and the patient has requested a new crown is made.
State 2 factors determining post length.
* The Length of the root canal length of the post = root cnal length -3mm
(3-5mm of GP should be left at the apical part of the RCT)
* remaining bone support- the alveolar bone should be at least half of the post length into the root.
* Crown height - it should be a 1:1 post length to crown length ratio.
170
Your patient has attended with gross caries. The cavity has been prepped but it is unretentive for amalgam.
List 4 alterative techniques or materials.
Alternative Techniques:
- Composite restoration
- Indirect Onlay/ inlay/ crown (Metal/ porcelain/composite)
- Crown with post & core. (Posts metal/fibre/ceramic)
171
Your patient has attended with gross caries. Since the tooth hasn't been root treated. What two things will you be looking for at review. (4)
Symptoms
Sensibility testing
Radiographic changes.
TTP
172
Your patient has attended with gross caries.
How does the clinical presentation of caries compare to the radiograph
Caries is generally (2-3mm) deeper clinically.
173
Describe the Cvek pupotomy proecure and how it is different from a normal pulpotomy procedure.
This is a partial pulpotomy procedure.
Partial pulpotomy- only the necrotic pulp is removed from the tooth. (1-3mm) . You use cotton pledget with saline (adult teeth) to achieve haemostasis. You then use CaoH on the pulp as a pulp cap. Restore with a GIC core and then a composite bandage or definitve restoration
Coronal pulpotomy- the coronal pulp is removed from the tooth then CaOH + gic then restored.
Pulpectomy- the entire pulp is removed from the tooth. .
174
Mrs Patel is 45 and has soreness in her right cheek which is reddened on the buccal mucosa with a short Lacey edge immediately adjacent to tooth 47. This tooth is perfectly sound amalgam with abutments for rest seats and clasps on CoCr partial denture which has been worn for 5 years.
Bleeding 6mm mesio-buccal pocket with associated grade 1 mobility. Periapical shows 47 has mesial bone loss but no periapical pathology
What are your provisional diagnosis? (3)
Traumatic keratosis from denture clasps
Lichenoid reaction to large amalgam restoration
Localised periodontal disease to the 47 - worsened by RPD margins and clasps.
Raticular lichen planus?? incidental location
175
Mrs Patel is 45 and has soreness in her right cheek which is reddened on the buccal mucosa with a shorty Lacey edge immediately adjacent to tooth 47.
This tooth is perfectly sound amalgam with abutments for rest seats and clasps on CoCr partial denture which has been worn for 5 years.
Bleeding associated with a 6mm mesio-buccal pocket and grade 1 mobility.
Periapical radiograph shows 47 has mesial bone loss but no periapical pathology.
What additional investigations could be undertaken and how would you arrange these? (3)
Periodontal check - Assess risk factors, 6 point pocket chart and plaque and bleeding scores
Clinical photographs
Refer to Oral medicine for advice (Replacing amalgam with composite.)
May require incisional biopsy if the reaction doesn't go away.
176
Mrs Patel is 45 and has soreness in her right cheek which is reddened on the buccal mucosa with a shorty Lacey edge immediately adjacent to tooth 47. This tooth is perfectly sound amalgam with abutments for rest seats and clasps on CoCr partial denture which has been worn for 5 years. Bleeding 6mm mesio-buccal pocket with associated grade 1 mobility. Periapical shows 47 has mesial bone loss but no periapical pathology.
What are Mrs Patel's options for management of these problems? (4)
Periodontal treatment (S3 guidelines) and review
Traumatic lesion- adjust the CoCr clasps/make a new denture and change location of clasps
then-
Oral med referal will decide if Lichen planus & identification of cause for correction- may be idiopathic.
Identifed through :
Blood test- Haematinics (deficiency)/ Autoantibody screening (For lupus erythematosis)/
Biopsy- To distinguish between lichen planus (unknown cause) and a lichenoid reaction (known cause)
MH- could be graft/host disease
From results:
Lichenoid reaction - only consider the removal of the amalgam in direct contact
- if asymptomatic a choice is to leave it however discuss the risks and benefits of removal: risk - removal of more tooth tissue & benefit = could be potentially malignant if we leave
- replace amalgam with composite
- if no resolution refer to oral med and potential biopsy
Lichen planus -Correct deficiency/ consider changing medications/ Symptom management (Chlorohexidine or benzdamine mouthwash. SLS free toothpaste
Biopsy result may mean referal for oral cancer.
177
You are carrying out root canal on an upper right canine under local anaesthetic. You are irritating the canal with dilute solution of sodium hypochlorite when the patient suddenly feels intense pain. Within minutes you notice a marked facial swelling in the area and profuse bleeding into the root canal from the periradicular tissues.
What is the most likely cause for these signs and symptoms and why?
Hypochlorite extrusion-
The NaOH has extruded through the apex of the RC.
Due to high pressure injection - not using first finger
injecting too deep - not having a stopper set to 2/3rds working length
locking the syringe in the canal.
This is an acute inflammatory reaction – which can be oedematous and/or hemorrhagic.
Can lead to significant tissue necrosis.
178
You are carrying out root canal on an upper right canine under local anaesthetic. You are irritating the canal with dilute solution of sodium hypochlorite when the patient suddenly feels intense pain. Within minutes you notice a marked facial swelling in the area and profuse bleeding into the root canal from the periradicular tissues.
What would be your immediate action?
Stop what you are doing.
Inform and Explain
1. Use LA to manage pain
2. Allow bleeding to continue until there is haemostasis.
3. Place a steroid containing intracanal medicament into the root canal e.g. odontopaste
4. Seal the coronal access cavity with a temp material
5. Advise pain relief and swelling advice
(Antibiotics are considered- to prevent secondary infection of the necrotic tissue)
6. review in 24 hours
179
You are carrying out root canal on an upper right canine under local anaesthetic. You are irritating the canal with dilute solution of sodium hypochlorite when the patient suddenly feels intense pain. Within minutes you notice a marked facial swelling in the area and profuse bleeding into the root canal from the periradicular tissues.
What would be your action after this? (4)
Advice on:
Pain relief
ibuprofen 400-600mg
Paracetamol 1000mg
QDS
Reduction of swelling/bruising:
Cold compress for first few days
Warm compress - resolution of soft tissue swelling & to eliminate haematoma (Severe bruise)
Prevention of secondary infection
Prescribe antibiotics
review in 24 hours
Refer if severe
180
You are carrying out root canal on an upper right canine under local anaesthetic. You are irritating the canal with dilute solution of sodium hypochlorite when the patient suddenly feels intense pain. Within minutes you notice a marked facial swelling in the area and profuse bleeding into the root canal from the periradicular tissues.
4 weeks later the patient’s condition has resolved and they return requesting that you continue with the root canal treatment, how would you prevent a similar incident from recurring? (3 + 8)
* Set silicone stop 2mm short of the working length
* While irrigating use your index finger rather than your thumb for the plunger
* The irrigating needle should always be loose in the root canal, keep the needle continuously moving and don't let it lock within the canal.
You can also:
1. Assess the pre-operative radiograph to look for open apices or perforations.
2. Assess the pre-endodontic state (can the tooth be isolated using a dental dam or do we need a pre-endodontic build up)
3. Patient should wear a disposable bib & eyewear.
4. Tooth should be isolated using a dental dam & oral seal
5. Dental dam should be tested by irrigating with chlorohexidine (ask if patient tastes)
6. Ensure all syringes are clearly labelled
7. Use a side vented needle for irrigation of the root canal.
8. Pass the syringe behind the patients head.
181
In what ways can we distribute local anaesthetic?
Infiltration- when the LA is deposited around the terminal branches of the nerve.
Block- When the LA is deposited beside the nerve trunk.
182
What is the mechanism of action of local anesthetic? (3)
Temporarily blocks voltage gated sodium channels
1. LA binds to the NA+ channel & blocks
2. This prevents Na+ influx & generation of the AP potential.
You don't need all the Na+ channels in the nerves to be blocked, You just need enough to prevent the nerve impulse being sent.
183
What nerve fibres are most susceptible to LA?
C (smallest)
DELTA
BETA
ALPHA
The small diameter axons have less Na channels so the number needed are blocked more quickly. (Mechano/ thermo/ noci/ chemoreceptors)
184
What are the constituents of local anaesthetic? (5)
Base hydrochloride - anaesthetic agent
aromatic region (Hydrophobic)
Ester or amide bond
Amine side chain (hydrophillic)
reducing agent: sodium metabisulfide,
preservative: methylparaban.
fungicide
+- vasoconstrictor
185
Name 1 ester and 3 amide local anaesthetic
Ester- benzocaine
Amide- Lignocaine. Articaine. Prilocaine
186
What is the maximum dose of lignocaine.
2.2ml 2% lignocaine 1:80,000 adrenaline.
Max dosage 4.4mg per kg. = 7 cartridges for 70kg person
187
What is reversible pulpitis?
List symptoms, causes and TX
Inflammation in the pulp that should resolve after removal of the stimuli. (remove the cause e.g. caries, exposed dentine)
Symptoms:
Sharp discomfort when stimulus (Cold/ sweet) is applied but resolves instantly once stimulus removed
Causes:
exposed dentine
caries
deep restorations
188
What is symptomatic irreversible pulpitis?
List symptoms, causes and TX
Findings indicate that the vital inflamed pulp is incapable of healing. (Pulpectomy/RCT/extraction)
Symptoms:
pain upon thermal stimulus that lingers - often 30 seconds or longer after stimulus removal
spontaneity (unprovoked pain)
Referred pain.
postural pain
over-the-counter analgesics are typically ineffective.
Common causes: deep caries, extensive restorations, or fractures exposing the pulpal tissues.
189
What are the signs and symptoms of symptomatic irreversible pulpitis? (6)
* Sharp pain upon theraml stimulus
* Lingering thermal pain (30s or longer after removal of stimulus)
* Spontaneous/ referred pain.
* Pain keeps patient up at night- there is an increased pulpal pressure when lying down and patient not distracted
* Over the counter analgesics are typically ineffective.
* The infection has not reached the periapical tissues so not TTP.
190
What are some common causes of symptomatic irreversible pulpitis? (3)
Deep caries
Extensive restorations
Fractures exposing pulpal tissues.
191
How is irreversible pulpitis managed?
Root canal treatment
extraction .
192
Draw the endodontic access cavities for maxillary and mandibular
-incisors
-canines
-Premolars
-Molars
193
What is the thickness of articulating paper
20um (microns) used with millers forceps.
194
State three sequelae of dental trauma that may influence your treatment planning for a discoloured tooth? .
| 2020 paper Q3
* Is the tooth mobile?
* Is the tooth vital (is the pulp necrotic/ healthy /Sclerosed)?
* Is there any pathology or infection? -Cyst/ periapical pathology.
