Endo Flashcards
(295 cards)
1
Q
What are the five biological objectives of endodontic treatment?
A
1) confine
2) prevent
3) remove
4) attempt
5) create
2
Q
What does “confine” refer to in the endo biological objectives?
A
confine instrumentation to within the root canal
3
Q
What does “prevent” refer to in the endo biological objectives?
A
prevent extrusion of necrotic debris in the periapical tissues
4
Q
What does “remove” refer to in the endo biological objectives?
A
remove all vital and necrotic tissue from the root canal system
5
Q
What does “attempt” refer to in the endo biological objectives?
A
attempt to complete all cleaning and shaping in one visit
6
Q
What does “create” refer to in the endo biological objectives?
A
create sufficient space and taper for irrigation and placement of inter-appointment medicament
7
Q
In Vertucci’s canal configurations, what types have only one canal at the apex?
A
type I, II and III
8
Q
In Vertucci’s canal configurations, what types have two canals at the apex?
A
Type IV, V, VI and VII
9
Q
In Vertucci’s canal configurations, what types have three canals at the apex?
A
Type VIII only
10
Q
What three distinct patterns do accessory canals in mandibular first molars appear in?
A
1) in 13% a single furcation canal extends from pulp chamber to intraradicular region
2) in 23% a lateral canal extends from coronal third of major root canal to the furcation region (80% from distal canal)
3) about 10% have both lateral and furcation canals
11
Q
Where is the apical limit for endo preparation?
A
Apical constriction
12
Q
What is a general rule for locating the canals in endo?
A
you should not have to cross the oblique ridge in order to find all of the canals (usually mesially placed)
13
Q
Generally, what is the distance from the pulpal floor to the furcation?
A
3mm
14
Q
Generally, what is the height of the pulp chamber? (mandibular and maxillary molars)
A
mandibular molars - 1.5mm
maxillary molars - 2mm
15
Q
Generally, what is the height from the buccal cusp to the pulp chamber roof?
A
maxillary and mandibular 6mm
16
Q
In what percentage of mandibular and maxillary molars are the pulp chamber ceiling and CEJ coincident?
A
mandibular molars - 98%
maxillary molars - 97%
17
Q
What root canals are present in a maxillary first molar?
A
3 - P, MB and DB
18
Q
How many canals are there in a maxillary first molar?
A
3-4 canals
P, MB1, MB2, DB
MB2 located on line between MB and P orifices
19
Q
How many canals are there in a maxillary second molar?
A
usually 3 (MB, DB, P), always look for 4
more variety in 2nd molar than 1st molar
20
Q
How many roots are there in a mandibular first molar?
A
2 well formed roots
21
Q
How many canals are there in the M root of the mandibular first molar?
A
2 canals - MB and ML
22
Q
How many canals are there in the D root of the mandibular first molar?
A
1 or 2 - DB and/or DL
23
Q
How many roots are there in a mandibular second molar?
A
two roots
24
Q
How many root canals are in a mandibular second molar?
A
usually 3, always look for 4
25
What is considered one of the most important factors in enabling efficient and effective root canal preparation and obturation?
correctly sized and sited access cavity
26
What are the objectives of an access cavity?
- remove all caries
- conserve as much tooth tissue as possible
- remove roof of pulp chamber and pulp horns, create smooth axial walls
- remove all coronal pulp tissue
- locate all canal orifices
- avoid damage to pulpal floor or perforation
- achieve straight-line access to AF or initial curvature
- minimise marginal leakage of restored tooth
27
What is the access cavity design for maxillary molars?
- blunted triangle outline
- base of triangle toward buccal
- apex of triangle towards palatal
- orifice positioned at each angle of triangle
- access cavity entirely within M half of tooth
28
What is the access cavity design for mandibular molars?
- rhomboid shape to allow for exploration of second distal canal
- access cavity within mesial half of tooth but extended as far distally as necessary to allow ease of positioning of instruments
29
What complications can be caused by inadequate opening during access preparation?
- compromised cleaning and shaping of canals
- compromised instrumentation
- coronal discolouration
- prevents good obturation
- instrument breakage
- perforation
- ledging
30
What complications can arise by mutilation of coronal tooth due to removal of too much tooth structure in access preparation?
coronal fracture
31
What complications can arise due to inadequate caries removal in access preparation?
- carious destruction of tooth
- discolouration
32
What complications can arise due to labial/furcal perforation during access preparation?
- can cause periodontal destruction
- weakens tooth structure
33
What kind of debris can be created and cause the blockage of canals or orifices?
dentinal debris
amalgam fillings
34
What type of ProTaper files were designed in 2022?
ProTaper Ultimate
35
What is the special feature of ProTaper Gold instruments?
controlled memory
36
How is controlled memory instilled in ProTaper Gold instruments?
- files undergo multiple heating and cooling cycles
- reaches optimal phase transformation from martensite to austenite
37
What does the controlled memory characteristic of ProTaper gold instruments provide?
greater flexibility
improved resistance to cyclical metal fatigue
38
What lengths of ProTaper gold files are available?
21mm, 25mm and 31mm
39
What files are shaping files?
SX, S1 and S2
40
What files are finishing files?
F1, F2, F3, F4, F5
41
What is the cross down sequence?
flaring the coronal third using SX to achieve straight line access
42
How do you shape the coronal 2/3?
-flood access cavity with sodium hypochlorite
- use SX to flare coronal orifice and achieve straight line access
- irrigate
- glide path - scout coronal 2/3 with size 08 or 10 flexofile with paste lubricant, precurve tip in curved canals
- expand glide path with proglider
- irrigate
- shape coronal 2/3 with S1, brush, follow, irrigate, recapitulate, irrigate
- shape coronal 2/3 with S2, brush, follow, irrigate, recapitulate, irrigate
43
At what speed and torque is the SX used?
- 300 rpm
- 2Ncm
44
At what speed and torque is the ProGlider used?
- 300 rpm
- 2 Ncm
45
At what speed and torque is the S1 shaping file used?
300 rpm
4 Ncm
46
At what speed and toque is the S2 shaping file used?
300 rpm
4 Ncm
47
What are the 6 steps of endo instrumentation?
1) coronal 2/3 shaping
2) working length
3) shape apical 1/3
4) finish apical 1/3
5) final irrigation
6) obturation
48
How do you establish the working length?
- place a size 10 flexofile in each canal in turn
- ideally use electronic apex locator
- if not take WL radiograph using reproducible reference point (cusp tip)
- record length and ref point in pt notes
- achieve apical patency
49
Where should endodontic preparation end?
at the junction of pulpal and periodontal tissue
apical constriction
50
What is apical patency?
the ability to pass a small flexofile passively through the apical constriction without widening it
51
How do you establish working length with the EAL?
- Use EAL and size 10 flexofile
- irrigant in canal but not pulp chamber
- ask patient to wet lip clip with tongue
- ensure no contact with metal restorations when file in canal
- use a little Glyde to improve conductivity
52
What steps are involved in the shaping of the apical 1/3 of the tooth?
- take glide path to WL
- ensure size 10 flexofile is loose at WL, expand glide path using ProGlider
- irrigate with sodium hypochlorite
- use S1, brush, follow to WL, irrigate, recapitulate, irrigate
- use S2, brush, follow to WL, irrigate, recapitulate, irrigate
53
What is involved with finishing the apical third?
- Use F1 to WL, follow
- gauge with size 20 flexofile and inspect F1 file for debris on apical flutes
- irrigate, recapitulate, irrigate
- when required, use F2 to WL and repeat apical gauging procedure
- continue until correct apical size achieved
54
What is involved in the final irrigation?
- 3ml sodium hypochlorite (+ultrasonic activation)
- 3ml citric acid (+ultrasonic activation)
- 3ml sodium hypochlorite
- dry canals with corresponding size paper points and dress with non-setting calcium hydroxide, cotton wool/sponge, coltosol, glass ionomer
55
What is involved in the obturation step?
- pt returns, check dressing intact, symptoms improved and no presence of sinus
- give LA, place rubber dam and remove dressing
- irrigate canals with citric acid to remove CaOH paste, leave canals wet
- select correct size gutta percha master points, measure to correct WL and place in the canals to take radiograph (trial point or master apical cone radiograph)
- have checked and carry out repeat final irrigation
- dry canals to WL
- use minimum sealer and lateral compaction using size B finger spreader and size B accessory cones
56
How do you obturate converging canals?
- during insertion of GP points for MAC radiograph, you will be unable to seat both cones to full WL
- one GP should be placed to full WL
- 2nd GP is inserted as fat as possible (short of WL)
- remove this GP point and measure how short it is
- cut this length off from apical end
- it should now reach the point of merger
- trial cone radiograph
- following final irrigation and drying of canals, obturate the first canal to WL then obturate 2nd using the slightly shorter cone
57
Different species of microbes dominate at different stages of the endodontic process, what factors influence which microbes are present?
- availability of nutrition
- oxygen level (redox potential)
- local pH
58
What is the development of a biofilm?
-deposition of a conditioning film
- adhesion and colonisation of planktonic microorganisms in an extracellular amorphous matrix
59
What is the function of a biofilm?
biofilms protect microorganisms from adverse environmental changes and effects of biocides
60
Is rotary of mechanical instrumentation better at removing the biofilm?
rotary instrumentation is not any better at removing bacteria.
61
What is a limitation of instrumentation?
In oval shaped canals only 40% of the walls can be contacted by the instruments
62
What is the chemical objective of a root canal irrigant?
- inactivate biofilm and endotoxins, dissolve tissue remnants/smear layer
63
What is the physical objective of a root canal irrigant?
allow flow of irrigant throughout RCS so as to detach biofilm, flush out debris
64
What are the properties of an ideal irrigant?
- broad antimicrobial spectrum against anaerobic and facultative microbes organised in biofilms
- dissolve necrotic pulp tissue remnants
- dissolve smear layer
- be systemically non-toxic
- non caustic to periodontal tissues
- little potential of anaphylactic reaction
65
What will laminar flow of irrigants in root canals do?
will remove planktonic bacteria
only effective slightly beyond tip of needle - area of stagnation known as vapour lock effect
66
What is a disadvantage of laminar flow of irrigants?
only effective slightly beyond tip of needle - area of stagnation known as vapour lock effect
67
What is turbulent flow of irrigants in root canals?
acoustic streaming, cavitation
- caused by agitation of irrigation solutions, more likely to penetrate RCS and disrupt/remove biofilm
68
What type of flow of irrigant is most likely to penetrate the RCS and disrupt/remove the biofilm?
turbulent flow
69
What frequency does ultrasonic disinfection of the RCS operate at?
25000 cycles/second
70
What does ultrasonic disinfection of the RCS involve?
acoustic streaming, cavitation and increase in temperature of irrigant
71
Why is the pulpal floor sealed following obturation?
entrance to root canals and floor of pulp sealed to prevent coronal leakage
72
What is used to seal the pulpal floor?
resin modified GI (vitrebond)
smart dentine replacement (SDR) -
73
What is smart dentine replacement?
a flowable bulk filler that can be placed up to 4mm, self levels and minimises shrinkage stress
74
How do you provide the coronal seal following obturation?
- clean access cavity with alcohol on microbrush
- etch and bond access cavity
- place SDR in pulp chamber and access cavity
- leave 2mm to be filled with conventional composite if an indirect restoration is not prescribed
75
When should an endodontic treatment be reviewed?
clinical and radiographic follow-up at least 1 year after treatment
76
What is an endodontic emergency?
defined as pain or swelling caused by various stages of inflammation or infection of the pulpal or periapical tissues
77
What are the causes of an endodontic emergency?
usually caries or defective restorations
85% of all dental emergencies are as a result of pulpal or periapical disease requiring either RCT or extraction to relieve the symptoms
78
What are the four main types of endodontic pain?
1) pre-treatment pain
2) inter-appointment pain
3) pain immediately following obturation
4) pain occurring some time later associated with a previously treated tooth
79
Which analgesics are used to manage endodontic pain?
- paracetamol and/or ibuprofen
- diclofenac, co-codamol
beware of CI and cautions
80
Which antibiotics are used to manage endodontic pain?
for dental infection in adults either
- amoxicillin, 1x500mg cap 3x daily OR
- phenoxymethylpenicillin, 2x250mg tabs 4x daily OR
- metronidazole 1x400mg tab 3x daily
81
What is the recommended regimen of paracetamol for adults in dental pain (5 day regimen)?
2x500mg tablets up to 4x daily (every 4-6hrs)
82
What is the recommended regimen of ibuprofen for adults in dental pain (5 day regimen)?
2x200mg tablets up to 4x daily (every 4-6hrs) preferably after food
83
For moderate to severe dental pain for adults, what is an appropriate 5 day regimen?
either:
- increase dose of ibuprofen to 3x200mg up to 4x daily
- ibuprofen and paracetamol together, preferably after food without exceeding dose or freq of either drug
- di-clofenac (1x50mg tab 3x daily) and paracetamol together, preferably after food
84
For patients with severe infections (e.g. EO swelling, eye closing, trismus) what can be done to the dose of amoxicillin and phenoxymethylpenicillin?
it can be doubled
85
What is the maximum drug dose of paracetamol in a 24 hour period?
4g
86
What is the maximum drug dose of ibuprofen in a 24 hour period?
2.4g
87
What is the maximum drug dose of diclofenac in a 24 hour period?
150mg
88
What is dentine hypersensitivity?
an exaggerated response to application of a stimulus to exposed dentine regardless of its location. Short, sharp pain from exposed dentine in response to stimuli which cannot be ascribed to any other dental defect or pathology.
89
What kind of pain is experienced in dentine hypersensitivity?
short, sharp pain
90
What happens within the tooth to cause dentine hypersensitivity?
rapid fluid flow in dentinal tubules
hydrodynamic activation of A delta fibres
91
What are the stimuli for dentinal hypersensitivity?
- cold
- air (desiccating)
- hypertonic chemicals
92
What is the treatment for dentine hypersensitivity?
desensitising agents:
- disturb the transmission of nerve impulses agent - potassium nitrate
- occlude dentinal tubules agent - fluorides, adhesive systems, bioglass, oxalates, varnishes, lazer, casein-phosphopeptide-amorphous calcium phosphate
93
What are the symptoms of a reversible pulpitis?
- sharp pain to cold or sweet, salty, sour
- lasts a few seconds
94
What are the causes of a reversible pulpitis?
- caries into dentine
- broken, worn teeth
- defective restorations
- recent dental treatment
95
What is the treatment for a reversible pulpitis?
NOT a dental emergency
- usually just requires caries removal and a restoration/dressing to cover exposed dentine
- review periodically as pulp may quietly become necrotic (sensitivity testing)
96
What is irreversible pulpitis?
irritation of pulp continues from reversible pulpitis
- a severe inflammation that WILL NOT resolve even if cause removed
- pulp will slowly or quickly become necrotic
97
How can some irreversible pulpitis cases be asymptomatic?
no symptoms but deep caries or loss of tooth structure that if left untreated will cause symptoms of the tooth to become non-vital
98
How does a symptomatic irreversible pulpitis present?
- intermittent or spontaneous pain
- lasts only minutes or lasts for hours
- pain may be induced by exposure to extreme temperatures
- pain may be very difficult to localise in early stages
99
What is the treatment for an irreversible pulpitis?
once located correct tooth:
- RCT (if tooth restorable) - source of infection removed, complete cleaning and shaping in 1st visit where possible using CaOH as interappointment dressing
- Emergency pulpotomy (removal of coronal pulp tissue) and dressing with ledermix or odontopaste until RCT can be carried out
- Extraction
100
What symptoms are present in an advanced symptomatic pulpitis?
- excruciating acute pain
- momentarily relieved by cold
- often TTP as inflammation has extended periapically
- reacts violently to heat
- radiograph shows thickening of PDL
101
What are the treatment options for an advanced symptomatic pulpitis?
RCT
Pulpotomy if time is limited, adjust occlusion
extraction
DO NOT PRESCRIBE ANTIBIOTICS
102
When is an emergency pulpotomy indicated and what does it do?
- insufficient time to complete pulp extripation, cleaning and shaping of root canals
- alleviates pain until next appointment
- do not start canal prep in cases of IP if insufficient time
103
What is the method for carrying out an emergency pulpotomy?
- LA
- rubber dam
- completely open pulp chamber
- wash gently with sodium hypochlorite
- amputate coronal stump using high speed
- wash and dry with CW
- seal odontopaste/ledermix into pulp chamber
104
What is ledermix?
combines the antibiotic action of demeclocycline hydrochloride with the anti-inflammatory action of triamcinolone acetonide. Used as a dressing or lining under temporary or definitive restorations
- demeclocycline hydrochloride, triamcinolone acetonide
105
What is odontopaste?
A zinc-oxide based endodontic dressing used to reduce pain, as well as to maintain a bacteria-free environment within the root canal. Contains broad spectrum antibiotic clindamycin hydrochloride, and triamcinolone acetonide a steroid-based anti-inflammatory agent, and calcium hydroxide.
106
What is vital pulp therapy for the treatment of IP?
the complete removal of the coronal pulp and application of a biomaterial directly onto the pulp tissue at the level of the canal orifices, prior to the placement of a direct restoration.
materials - MTA or biodentine
107
What materials are used to place the direct restoration in a vital pulp therapy for the treatment of IP?
MTA or biodentine
108
What are the contraindications for the use of odontopaste?
- not suitable for pregnant women as triamcinolone acetonide has shown teratogenic effects on test animals
- not suitable for patients with allergy to lincomycin or clindamycin
- not used on patients taking concurrent doses of erythromycin as antagonism demonstrated
- used with caution in patients with history of GI disease, particularly colitis
- used with caution on nursing mothers as clindamycin shown to be present in breast milk
109
What are the contraindications for the use of ledermix?
- not be used during pregnancy or lactation
- glucocorticoids pass into breast milk, triamcinolone inadvisable in first 5 months of pregnancy in particular.
- demeclocycline penetrates placenta membrane and excreted in breast milk - antianabolic effect and teratogenic effects including deposits in bones and teeth
110
What is pulpal necrosis?
complete breakdown of the pulpal tissue
111
What causes pulpal necrosis?
bacteria reach the pulp - direct exposure, dentinal tubules, cracks in enamel or dentine
112
What causes symptomatic periapical periodontitis?
- bacteria, toxins from infected, necrotic pulp
- procedures during RCT such as over-instrumentation that pushes debris beyond the apex
113
How do patients with symptomatic periapical periodontitis present clinically?
Pain - tender to biting
114
How do patients with symptomatic periapical periodontitis present radiographically?
radiolucent area around apex of tooth
pt should be seen ASAP for treatment
115
What can cause a tissue swelling?
- acute periapical abscess
- interappointment flare-up
- post-endodontic complication
116
What kind of swellings can occur?
- localised or diffuse
- diffuse swelling (cellulitis - more extensive spreading through adjacent soft tissues and tissue spaces along fascial planes)
- fluctuant or firm
117
How are tissue swellings managed?
- achieve drainage - through RC or incision of fluctuant swelling
- remove source of infection by disinfection of the root canal
118
What is the cause of an acute apical abscess?
- severe inflammatory response to bacteria/irritants in necrotic pulp
- bacteria from an infected root canal enters the periapical tissues and the immune system is unable to suppress the invasion
- can be acute flare-up of a chronic periapical lesion
119
How does an acute apical abscess present clinically?
- PAIN, exquisitely tender to touch
- tooth extruded from socket
- swelling - localised or diffuse, fluctuant (submucosal) or non-fluctuant (subperiosteal)
- mobility of tooth
- systemic involvement - high temperature, fever, feeling unwell, lymphadenopathy
120
What treatment is required in the case of an acute apical abscess?
treatment required urgently
- removal of irritants - through cleaning and shaping of canal(s), copious irrigation with sodium hypochlorite
- drainage:
1. incisional - soft tissue if localised, fluctuant swelling
2. through RC - may drain freely, if not place size 10 or 15 file 1-3mm through apex
relief of pressure = instant relief of pain
121
Once the tooth has been drained in an acute apical abscess, what is done?
avoid leaving tooth on open drainage
- tooth becomes heavily infected resulting in higher incidence of flare-ups
- persistent purulence - allow pt to sit/lie 30 mins with RD
- dress with CaOH and seal abscess
- relieve occlusion
- review in 24 hrs
122
What is a diffuse swelling?
cellulitis - spread into fascial planes
123
What are the systemic signs present in diffuse swelling?
- high temperature >38 degrees
- feeling unwell
124
What treatment can be done when there is a diffuse swelling?
drainage through the tooth does often not occur.
May require incision through the mucoperiosteum with insertion of a drain (OS)
Antibiotics - progressive or persistent infection with systemic signs and symptoms, could be life threatening
125
In what situations do you NOT prescribe antibiotics?
- irreversible pulpitis
- symptomatic apical periodontitis
- draining sinus tracts (chronic abscess)
- after endo surgery to prevent flare-ups
- after incision for drainage of a local swelling (without cellulitis, fever or lymphadenopathy)
126
What are analgesics indicated for?
pain control
127
When should antibiotics be prescribed in endo?
- where there is a diffuse swelling/cellulitis
- when drainage cannot be achieved
- patient has systemic involvement
128
What concerns are there regarding swelling in endo where a patient should be referred to hospital for IV antibiotics?
- Ludwigs angina
- Cervical fasciitis
129
What regimen of phenoxymethylpenicillin is prescribed in endo infection?
1x 250mg tab 4x daily for 5 days
Dose doubled for severe infections
130
What type of microbes does phenoxymethylpenicillin act upon?
facultative and strict anaerobes
- gram-positive faultative - streptococci, enterococci
- anaerobes - porphyromonas, prevotella, fusobacterium, actinomyces
131
Name four anaerobes
porphyromonas
prevotella
fusobacterium
actinomyces
132
Name two gram positive facultative anaerobes
streptococci
enterococci
133
What is amoxicillin successful at treating and what is it more effective than?
- effective at treating dental abscesses and better absorbed than phenoxymethylpenicillin
134
What is the regimen of amoxicillin usually prescribed for patients?
1x 500mg capsule 3x daily for 5 days
135
What is the regimen of metronidazole usually prescribed for patients?
1x 400mg tablet 3x daily for 5 days
136
How does metronidazole work and what is it effective against?
bactericidal against strict anaerobes
no activity against aerobes or facultative anaerobes
137
When is metronidazole indicated?
in patients with penicillin allergy
use as adjunct to amoxicillin in patients with spreading infection or pyrexia
138
In what population may metronidazole be contraindicated?
anticoagulant effect in warfarin users may be enhanced.
avoid alcohol
139
What regimen of ibuprofen is usually recommended for patients?
1x 400mg tablet 4x daily preferably after food
140
When should ibuprofen be avoided?
hypersensitivity to aspirin, low dose aspirin daily
141
What is the regimen for diclofenac?
1x 50mg tablet 3x daily for 5 days
142
What is the usual regimen for paracetamol?
2x 500mg tablets 4x daily
143
When can pain during treatment be an issue?
- failure of LA
- pain during shaping and cleaning
- pain after obturation
144
Why is lip numbness not always a good indicator of anaesthesia for IANB?
IANB given to pts with irreversible pulpitis of mandibular molars have on average 55% incidence of pulpal anaesthesia even in presence of 100% lip numbness
145
What effect can inflammation have on the success of LA?
- LA diffuses across cell membrane to block Na channels, requires drug to change from acid to base form
- LA pH is low
- once injected the local tissue pH and drug's strength as an acid (pKa) regulates distribution of LA between acid and base forms
- proportion of uncharged base form is available to diffuse
- inflammation can cause ion trapping of LA in charged acid form rendering it unable to cross cell membrane
- inside the cell it is the acid form that blocks Na channels
- basically less acid LA available to block channels
146
What can be done to try to improve LA success in inflamed tissues?
use LA with lower pKa values e.g. mepivacaine
147
What impact does the effect of inflammation on blood flow have on LA success?
- peripheral vasodilation induced by inflammatory mediators can reduce concentration of LA by increasing rate of systemic absorption
148
What impact does inflammation have on nociceptors?
- inflammatory mediators can activate or sensitise nociceptors and cause nerve sprouting (increases size of receptive field)
149
What impact can inflammation have on central sensitization?
- can induce changes in CNS processing system
- increased excitability of central neurons (hyperalgesia)
- exaggerated response to gentle peripheral stimuli
150
What is an endodontic flare-up?
an acute exacerbation after the initiation or continuation of RCT
151
What causes an endodontic flare-up?
- preparation beyond the apex
- over instrumentation
- pushing debris into periapical tissues
- incomplete removal of pulpal tissue
- overextension of RCT filling material
- chemical irritants (irrigants, medicaments, sealers)
- hyperocclusion
- root fractures
- microbial factors
152
Is it recommended that re-treatment of teeth with apical periodontitis is completed in one visit?
no
153
What can cause pain following canal preparation appointment?
apical extrusion of debris via:
- over instrumentation (enlargement of foramen)
- incomplete debridement (vital pulp remnants)
- undetected canals
- apical, lateral perforation during preparation
- temp dressing supra-occlusion
154
What does pain following canal preparation result in and how is it managed?
- results in inflammation of periradicular tissues
- antibiotics are ineffective, do NOT prescribe
- alleviated with non-steroidal anti-inflammatory analgesics
155
What should NEVER be done with sodium hypochlorite irrigant?
NEVER wedge the needle in a canal
156
What can the forceful expression of sodium hypochlorite cause?
- sudden, prolonged and sharp pain
- rapid and diffuse swelling
- haemorrhagic reaction
157
What is a sign that irrigant has been extruded?
Hulsmann's criteria
- acute pain, swelling, redness
- progressive swelling, infraorbital region or mouth angle
- profuse haemorrhage
- numbness, weakness of facial nerve
- secondary infection, sinusitis, cellulitis
158
How is Hulsmann's criteria managed?
- irrigation with saline to reduce tissue damage
- analgesics
- reassurance
- cold packs 6hrs
- warm compresses several daily
- review after 1 day
may require referral to OS/Maxfax
159
What can cause pain following canal obturation?
- restoration in supraocclusion
- over-instrumentation, over-filling with GP (loss of apical constriction)
- sealers slightly toxic for first 24-48hrs
- root fracture - lateral compaction
160
What can cause pain some months following RCT?
- incomplete apical seal
- tooth in traumatic occlusion
- cracked, fractured tooth
- poor coronal seal - allowing re-contamination
161
What can cause coronal leakage?
- delay in placement of final restoration
- coronal temp filling is compromised
- tooth fractures and RCS exposed prior to placement of final restoration
- final restoration lacks marginal integrity
- recurrent decay present at margins
162
How can coronal leakage be prevented?
- thoroughness of obturation techniques
- temporary seal of RCS, during and after treatment
- choice and integrity of final tooth restoration
- do not delay placement of final restoration
- ensure tooth in atraumatic occlusion
- long term follow-up
163
What is cracked tooth syndrome?
-incomplete fracture of a vital posterior tooth that may or may not involve the pulp
164
What symptoms are present in cracked tooth syndrome?
consistent symptoms of pain to biting and temperature, particularly cold
165
What are craze lines?
visible fractures that only involve enamel
166
What is a fractured cusp?
- originate in the crown of the tooth, extend into dentine and terminate in the cervical region
- usually associated with large restorations causing unsupported cuspal enamel
167
What is a cracked tooth?
a crack extending from the occlusal surface of the tooth apically without separation of the two segments
168
What is a split tooth?
a crack that extends through both marginal ridges usually in the mesiodistal direction, splitting the tooth completely into 2 separate segments
169
What is a vertical root fracture?
originate in the root and are generally complete
170
What are the natural predisposing features for cracks?
- lingual inclination of the lingual cusps of mandibular molars
- bruxism, clenching
- extensive attrition and abrasion
171
What are the iatrogenic causes of cracks in teeth?
- rotary instruments - gates gliddens
- cavity preparation
- width and depth of the cavity
172
How are cracks diagnosed?
based on symptoms:
- localised pain on chewing or biting
- unexplained sensitivity to cold
- pain on release of pressure
173
What special investigations are done in the diagnosis of cracks?
- transillumination
- use of magnification
- removal of existing restoration/staining
- bite test tooth slooth - pain on release
174
What treatment options are available for cracked teeth?
- remove existing restoration
- evaluate health of pulp and remaining tooth structure
- if any indication of irreversible pulpitis/necrotic pulp then RCT before restoration
- during RCT tooth should be supported by use of an orthodontic band
- decide on definitive restoration - composite, onlay, crown
175
What causes the reduction in the moisture of teeth in older patients?
- tubular sclerosis
- secondary and reactionary dentine
176
What effect can eugenol have on dentine?
increases microhardness
177
What differences are present in the structure of collagen in the organic matrix of endodontically treated teeth?
- there are more immature cross links present
- may cause a decrease in tensile strength and an increase in brittleness
178
What are the four classifications of preoperative evaluation required prior to endo?
- endodontic
- periodontal
- restorative
- aesthetic
179
What do you search for/evaluate during an endodontic evaluation prior to endo?
- previously endodontically treated tooth
- quality of existing root canal filling
-clinical or radiographic signs of periapical pathology e.g. TTP, palpation tenderness, sinus, mobility, increased pocketing
180
What are the supracrestal attached tissues?
band of soft tissue attachment from the alveolar bone to the coronal extent of the junctional epithelium
181
What is the average width of the supracrestal attaches tissues and what effect does disease have on this?
2-3mm
distance remains constant in health and disease
182
What can result following the encroachment of restorations into the supracrestal attached tissues?
inflammation, formation of periodontal pockets and recession
183
What surgical procedure can be carried out if a tooth is deemed to not have sufficient coronal tooth structure to gain retention?
crown lengthening
184
What are two pathological causes of root perforation?
- inflammatory root resorption
- caries
185
What are two iatrogenic causes of root perforation?
endodontic
- over-instrumentation of root canal or furcation area
- post placement
186
What are root perforations repaired with?
MTA
187
What should you look for when doing your restorative evaluation prior to RCT?
is the tooth restorable following the RCT
- extensive caries, recurrent caries, large restorations, fractures, advanced periodontal disease
188
What five factors should you consider during your restorative evaluation prior to RCT?
1) amount of remaining tooth structure
2) anatomical position of the tooth
3) functional load on the tooth
4) aesthetic requirements of the tooth
5) coronal seal
189
What is the most important factor in determining the type of definitive restoration?
loss of tooth structure
190
In what teeth should the use of posts be avoided?
posterior teeth
191
Why should posts be avoided in posterior teeth?
- roots narrow and curved
- strip perforation can easily occur
192
What is the role of a definitive restoration in endo?
- protect against occlusal loads
- prevent microleakage
- integrate with remaining occlusion
- be of acceptable appearance
193
Where are onlays utilised and what is their function?
- posterior teeth
- preserves tooth structure - protects cusps
194
What types of onlay can you get?
metal
ceramic
195
What is a core?
a core material replaces missing coronal tooth structure prior to restoration with an indirect, extracoronal restoration and stabilises weakened parts of the tooth
196
What characteristics does amalgam provide as a core?
- high copper - spherical, lathe cut, admixed
- slow setting - best left 24hrs before tooth prep
- not technique sensitive
- strong if placed in bulk
- easily condensed, no voids
- not intrinsically adhesive - relies on mechanical retention or amalgam bonding
197
What is amalgam bonding and what are some examples?
a technique to bond amalgam to the tooth cavity
self curing metal adhesives, GI:
- resin cements (Panavia)
- adhesive bonding cements - all bond 2, amalgambond plus, optibond 2
198
What characteristics does composite resin possess as a core?
- aromatic dimethacrylate (BisGMA)
- filler particles, quartz, silica
- tooth coloured
- bonded to tooth structure
- immediate setting
- moisture sensitive
- polymerisation shrinkage
199
What are the advantages of composite resin as a core?
- bood bonding to tooth structure
- ceramic crowns
- easy to prepare
- good coronal seal
200
What are the disadvantages of composite resin as a core?
- difficult to differentiate from tooth
- expansion in water - die relief
201
What are hybrid composites?
composite resins with the addition of fibres, ceramic fillers, titanium and lathanide
202
What is Multicore Flow Blue (Ivoclar) an example of?
hybrid composite - coloured blue, used as core then covered
203
Why is bulk placement NOT recommended with conventional composites for cores?
- get shrinkage, leakage
- gap formation - caries, post op sensitivity
204
What technique is required for the placement of composite as a core?
- layering technique needed for composites to compensate for polymerisation stress
205
How can smart dentine replacement (SDR) be utilised in core placement?
can be used under a conventional composite to then bulk fill
206
What is smart dentine replacement and why is it useful?
- composite for posterior restorations (class I/II)
- flowable consistency (self levelling)
- universal shade
- simplified filling technique (bulk placement)
- 4mm depth of cure in 20 secs at 550mV/cm2
- fill 4mm depth then cover with conventional composite
207
What depth can SDR be placed in to "bulk fill"?
4mm
208
How can mechanical retention be provided for core build-ups without posts?
- pulp chamber in posterior teeth provides a natural undercut
- grooves and slots
- pins
209
How can chemical retention be provided for core build-ups without posts?
- bonding of composite
- amalgam bonding of core
210
What are two requirements for the utilisation of a Nayyar core?
- pulp chamber must be undercut
- pulp chamber must have sufficient depth
211
What is a Nayyar core?
retentive core produced by preparing the coronal 2 to 4 mm of the root canals and slightly undercutting the pulp chamber
212
What are the disadvantages of pins?
- induce internal stresses
- cause dentinal crazing
- self shearing pins often do not shear at full depth of pin hole
- fracture resistance of core reduced
- perforation into periodontium
213
If using pins, what should you aim to do?
- use minimum number
- coat in adhesive
- avoid furcation area
214
What are the disadvantages of posts in posterior teeth?
- posts do not reinforce the root but only retain the core
- roots are often curved and narrow
- can result in perforation or root fracture
215
What impact do posts have on strength of teeth?
they weaken rather than reinforce pulpless teeth
216
When are posts required in root filled anterior teeth?
if lack of coronal tooth structure to support the core
217
What are the causes of post failure?
- perforation
- cement failure
- root fracture
- coronal leakage
218
What does a poor coronal seal allow?
a restoration with a poor coronal seal will allow saliva, bacteria and endotoxins access to the root canal, leading to periradicular periodontitis
219
When should a permanent restoration ideally be placed following RCT?
as soon as possible in the absence of symptoms
220
What are the advantages of immediate post placement?
- familiarity of root canal morphology
- less risk of post perforation
- apical seal is not disrupted
- increased apical leakage after delayed post preparation
221
What burs/instruments are used in the mechanical removal of GP?
- ProTaper D files
- Gates Gliddens in sequence
222
What are the steps involved in the removal of gutta percha and placement of post?
- estimate length of tooth from radiograph
- determine post length required
- remember at least 4mm of GP must remain
- place rubber stop on gates gliddens burs at correct length
- use Gates gliddens burs in series from 2 upwards to remove GP
223
What post space preparation is required in the length of the tooth?
- 4-5mm GP should remain
- post length should be as long as possible
- short posts have poor retention and transmit larger lateral forces
224
What post space preparation is required for the width of the tooth?
- post length more important than diameter
- diameter of post should be no greater than 1/3 of diameter of root
225
What factors are linked to the length of post?
- increased risk of root fracture with short posts
- more favourable distribution of stress with longer posts
- longer posts have higher success rates
- increased diameter, apically increases risk of perforation
226
What is the ferrule effect provided by?
- bracing of the remaining tooth structure by the indirect restoration NOT the remaining coronal tooth structure
227
What measurement of ferrule is required at each point of the preparation?
1.5-2mm labially and palatally
1mm acceptable mesially and distally (stresses are less)
228
Where should a ferrule be placed?
1-2mm of tooth tissue coronal to finish line of crown
229
What are the advantages of placing a ferrule?
- improves fracture resistance
- reduces vertical fracture by 1/3
- more important than core material and post
230
What are the alternative options when there is insufficient coronal tooth tissue to place a ferrule?
- orthodontically extrude tooth
- crown lengthen
- accept poorer prognosis
- extract and replaced with bridge or implant
231
What are the two main types of post?
1) active - retention from root dentine by the use of threads
2) passive - rely on luting cement for retention
232
Name 8 post designs
1) threaded
2) serrated
3) smooth sided
4) parallel sided
5) cast
6) tapered
7) metal
8) non-metal
233
Out of threaded, smooth and serrated posts, which has the best and worst retention?
threaded = best
serrated
smooth = worst
234
Which has better retention - parallel sided or tapered posts?
parallel sided
235
What is more important for retention of a post - post length or post diameter?
post length
236
What are cast post and cores?
- smooth-sided, tapered posts that conform to the original taper of the root canal preparation
237
What is an advantage of a cast post and core?
conserves tooth tissue, reducing risk of apical perforation
238
What are the disadvantages of a cast post and core?
- least retentive design with high failure rate
- time consuming with laboratory costs
- porosities within casting can increase risk of post fracture
- placement of burnout posts into working models may result in shorter posts
239
What does the success of a preformed tapered post depend on?
- contact surface area
- taper and shape of post
- surface roughness
- width of cement lute
240
What is present in a parallel sided serrated post to dissipate pressure?
vertical vent to allow escape of excess cemetn
once seated the strain due to build up of hydraulic pressure will dissipate
241
What is an advantage of fibre posts?
they flex slightly and under load distribute stresses to the root dentine in a more favourable manner than metal posts
242
What does anisotropic mean?
different physical properties when loaded from different directions
243
What are the key characteristics of quartz fibre posts with a dual cure cement?
- mechanical properties similar to dental tissues
- bonding cement acts as a "force breaker"
- fibre density important for strength
- strength significantly reduced by moisture
244
What significantly reduced the strength of quartz fibre posts with a dual cure cement?
moisture
245
What property is important for strength of quartz fibre posts with a dual cure cement?
fibre density
246
How should a post be cemented in place?
- post space needs to be clean, dry, free from saliva, sealer and GP
- rubber dam recommended
- paper points to dry canal
- place cement on post and into post space
247
What should be done for the improved retention of quartz fibre posts?
- removal of smear layer
- etching, bonding using microbrush and application of adhesive resin cement
- results in superior resin tag formation
248
What choices of luting cement for post-retained restorations are available?
- zinc phosphate
- glass ionomer
- composite resins (ACR - acrylic copolymer)
- polycarboxylate
- resin modified GI
249
What luting cement can cause issues with retrievability?
ACR (acrylic copolymer (composite resin)) makes removal of posts difficult
do not use as routine with metal posts -
250
How is the removal of a quartz fibre post carried out?
1) gain direct access to post
2) drill orientation hole with pilot drill
3) use removal drill at 15000rpm
4) use Peeso reamer size 2, apply pressure peripherally
5) take control radiograph, modify prep if required
6) finish preparation with appropriate twist drill
251
What is classified as a compromised anterior tooth?
- non-vital, immature teeth
- recurrent caries, pre-existing posts
- iatrogenic damage - large access preparations
- internal resorption
- developmental anomalies
- loss of apical constriction
252
What can be used to form an apical barrier?
Mineral trioxide aggregate
253
What is a diagnosis of the pulp an accumulation of?
a synthesis of history, clinical examination, special tests and radiological examination - NOT as the outcome of any one specific test
254
What is pulp sensibility testing used for?
- to reproduce the symptoms reported by the patient
- involves stimulating sensory nerve fibres
255
What does sensibility testing assess?
the integrity of the a delta fibres in the dentine-pulp complex by briefly applying a stimulus to the outer surface of the tooth
256
What is an accurate determinant of pulp vitality?
vascular supply NOT pulpal innervation
257
What are we referring to when we talk about pulp vitality?
blood supply of the pulp
258
What are we referring to when we talk about pulp sensibility?
Nerve supply of the pulp
259
What fibres are involved in pulpal innervation?
myelinated A delta and A beta fibres
Unmyelinated C fibres
260
What do A delta and A beta fibres do in the pulp?
- innervate dentine, A delta 90%
- low threshold
- stimulated by movement of dentinal fluid
- result in an acute sharp pain
261
What do C fibres do in the pulp?
- innervate body of the pulp
- high threshold
- can remain excitable even after compromised blood flow
- result in dull burning pain, poorly localised and can radiate
262
What are the key uses of pulp testing?
- prior to operative procedures
- diagnosis of pain
- investigation of radiolucent areas
- post-trauma assessment
263
What does a positive sensibility test indicate?
- indicates the presence of some nerve fibres carrying sensory impulses
- does not guarantee a healthy pulp
264
What are four examples of pulp sensibility tests?
- thermal testing
- electric pulp test
- test cavity preparation
- local anaesthetic test
265
How are the results of a sensibility test generally interpreted?
normal response = vital tooth or reversible pulpitis
intense, prolonged response = suggestive of irreversible pulpitis
no response = necrotic pulp or false negative (calcified canal, immature apex, recent trauma)
266
What does thermal testing involve?
application of cold or hot stimuli to a tooth to determine sensitivity to thermal changes
267
How are the results of a thermal test interpreted?
- response to cold = vital pulp, regardless of whether it is normal or compromised
- increased response to heat = suggestive of pulpal/periapical pathology
268
What physiological process occurs upon a cold test?
- causes contraction of dentinal fluid within the tubules, resulting in outward flow which results in hydrodynamic forces acting on A delta fibres leading to sharp sensation
269
What can a cold test be used to differentiate between?
- reversible pulpitis = pain subsides on removal of stimulus
- irreversible pulpitis = pain lingers after removal of stimulus
270
How is a cold test carried out?
- isolate with CW
- spray small piece of CW with endo frost
- place on control tooth, note reaction
- place on test tooth - compare
271
What temperature is ethyl chloride?
-5 degrees
272
What fibres does a heat test stimulate and what sensation is caused?
C fibres - dull pain of longer duration
273
How can a heat test be carried out?
- hot water - isolating with rubber dam and syringing hot water on one tooth at a time
- gutta percha heated in flame - difficult to use on posterior teeth
- excessive heating may result in pulpal damage
274
What nerve fibres are stimulated by EPT?
A delta fibres in pulp-dentine complex by applying an electric current to tooth surface
275
What physiological process happens to produce a positive EPT?
Ionic shift in the dentinal fluid within the tubules causing local depolarisation and subsequent generation of an AP from an intact A delta nerve
276
What is the technique used for EPT?
- Clean, dry and isolate tooth
- place conducting medium on electrode (prophy paste)
- place on incisal third of anterior tooth, and tip of MB cusp in molar teeth (highest innervation)
- increase level of current until sensation felt
277
What can cause a false positive when carrying out an EPT?
- electrode makes contact with gingiva or large amalgam restoration
- patient is anxious
- liquefaction necrosis
- tooth not dry or well isolated
278
What is a positive EPT result in a liquefaction necrosis due to?
teeth with acute alveolar abscess may respond positively to EPT because the gaseous and liquefied elements within the pulp can transmit electric charges to periapical tissues
279
How may a partial necrosis present on EPT?
Multi rooted teeth may respond positively even if only one root has vital nerve tissue
280
What may cause a false negative EPT result?
- patient is premedicated
- inadequate contact with enamel
- trauma
- canal is calcified
- apex is immature
281
Why may recent trauma cause a false negative EPT result?
in traumatic injuries, in cervical areas there will be temporary paraesthesia of nerves. If pulp vitality remains, the pulp will respond within normal limits after 30-60 days.
282
Why may a tooth with an immature apex present with a false negative EPT result?
- unreliable in immature teeth of young patients as these teeth contain fewer A delta fibres than mature teeth and myelinated fibres do not reach their maximal depth of penetration into pulp until the apex completes development
283
How are the results of an EPT generally interpreted?
- positive = presence of A delta fibres
- negative = pulpal necrosis
284
What is the test cavity preparation sensibility test?
last resort for testing pulp sensibility
- drill through enamel-dentine junction of un-anaesthetised tooth under rubber dam isolation using small round diamond
- if patient feels pain when dentine is reached the procedure is terminated and cavity restored
285
How is the local anaesthetic sensibility test carried out?
- using an infiltration, the most posterior tooth in suspected area is anaesthetised
- if pain persists, next tooth mesial also anaesthetised until pain disappears
- if source cannot be located between mandible and maxilla, IANB can be given
286
How is sensitivity calculated?
TP/TP+FN
287
How is specificity calculated?
TN/TN+FP
288
What is sensitivity defined as? (testing)
the ability of a test to detect disease in patients who actually have the disease i.e. ability to identify non-vital teeth
289
What is specificity defined as?
the ability of a test to detect the absence of disease i.e. ability to identify vital teeth
290
What does an assessment of pulpal vitality assess?
measures or assesses pulpal blood flow
vascular supply is most accurate marker of pulpal vitality
291
What is laser doppler flowmetry?
- optical measuring method that enables the number and velocity of particles conveyed by a fluid to be measured
- objective test of the presence of moving RBCs within a tissue
- laser light transmitted to dental pulp by means of fibre optic probe placed against tooth surface
292
What are the indicators for use of laser doppler flowmetry?
- pulp testing in children
- traumatised teeth
- monitoring revascularisation of replanted teeth
- differential diagnosis of periapical radiolucencies
293
What sensibility test is recommended following trauma of an immature permanent tooth with an open apex?
cold test
294
What sensibility test is recommended following trauma of an immature permanent tooth with pulp canal mineralisation?
EPT
295
What sensibility test is recommended following trauma of a mature permanent tooth with pulp canal mineralisation?
EPT
