4th year Flashcards
(296 cards)
1
Q
4 aims of the emergency dental treatment of traumatised teeth
A
Relieve pain
Treat pulp exposure
Immobilise displaced teeth
Provide antiseptics/antibiotics to prevent infection
2
Q
4 potential radiographs for traumatised patients and when they are indicated
A
Anterior occlusal
IOPA: if suspected root fracture
OPT: if suspected fractured mandible
Soft tissue: if suspected presence of tooth fragment/foreign body
3
Q
Define crown infractions
A
Incomplete fracture of enamel without loss of tooth structure
4
Q
Define uncomplicated crown fracture
A
Enamel or enamel and dentine fracture where pulp not exposed
5
Q
Define complicated crown fracture
A
Enamel and dentine fracture and pulp is exposed
6
Q
Management of crown infractions
A
Monitor vitality, no treatment needed
7
Q
2 managements of small uncomplicated crown fracture
A
Smooth if minimal
Etch, bond and composite/rebond tooth fragment
8
Q
2 managements of large uncomplicated crown fracture
A
Etch bond and composite/bond tooth fragment
If close to pulp consider indirect pulp cap with dycal before restoring with composite or bonded tooth fragment
9
Q
Method of rebonding a tooth fragment
A
Make sure tooth fragment is clean
Bevel fragment and tooth, etch, bond and use composite to bond fragment to tooth
10
Q
Management of complicated crown fracture with small exposure (<2mm), < 24 hours since injury
A
Dycal, MTA or Biodentine pulp cap and restore with composite resin or rebond tooth fragment
11
Q
Management of complicated crown fracture with big exposure, < 24 hours since injury
A
Partial pulpotomy (remove coronal 2mm), achieve haemostasis, cover with Dycal or Biodentine and restore with composite
12
Q
Management of complicated crown fracture with big exposure, > 24 hours since injury
A
Extirpate pulp and carry out RCT
13
Q
3 follow-up times for crown fracture
A
Review clinically and radiographically at
1 month
2 months
1 year
14
Q
Define crown-root fracture
A
Fracture involving enamel, dentine, cementum and the root of the tooth
15
Q
Emergency management of crown-root fracture
A
Twist flex wire and composite to splint fractured tooth to adjacent teeth to relieve pain on biting for 2-4 weeks
16
Q
3 management options for crown-root fracture
A
Remove fractured coronal fragment, restore tooth
Remove fractured coronal fragment and extrude root surgically or orthodontically and restore
Extraction in extensive crown-root fractures
17
Q
Define root fracture
A
Fracture confined to the root of the tooth involving cementum, dentine, and the pulp
18
Q
3 levels of root fractures
A
Cervical 1/3
Middle 1/3
Apical 1/3
19
Q
Emergency management of root fracture
A
Reposition coronal fragment and splint non-rigidly for 4 weeks
Vitality testing and review at 3 weeks, 6 weeks, 3 months, 6 months
20
Q
Management of root fracture with pulp necrosis
A
RCT of coronal fragment only
Dress with non-setting calcium hydroxide
Calcific barrier will form after 6-12 months, obturate with Gutta Percha
21
Q
What percentages of root fractures become necrotic
A
25%
22
Q
Define concussion injury
A
An injury to the tooth-supporting structures without increased mobility or displacement
23
Q
Describe the process of a concussion injury
A
Impact causes haemorrhage and oedema of periodontal ligament
24
Q
Define subluxation
A
No displacement but increased mobility
25
Describe the process of a subluxation injury
Some periodontal ligament fibres are ruptured, tooth loosened
26
Management of concussion and subluxation injuries
Soft diet
If tooth uncomfortable to bite on splint non-rigidly for < 2 weeks
Vitality test at time of injury, 1 month, 2 months
27
Define extrusion
Tooth displaced partially from socket as a result of periodontal ligament and pulp rupture
28
Define lateral luxation
Tooth displaced horizontally palatal/lingual causing contusion or fracture of alveolar socket walls
29
Management of extrusion
Reposition under LA
Splint non-rigidly for 2-3 weeks
Clinical radiographic review at 2-3 weeks
30
Management of lateral luxation
Repositioning under LA
Splint non-rigidly for 3 weeks
Clinical and radiographic review at 3 weeks
31
Define intrusion
Displacement of tooth into alveolar process
32
Describe the sound of an ankylosed tooth
High metallic tone as apex impacted into bone
33
Management of intrusion injury of tooth with immature root
Spontaneous re-eruption may be anticipated over several months
If after 10 days, no sign of movement, give LA and release tooth with forceps
Monitor pulpal healing with radiographs 3,4,6 weeks post-injury
34
Management of intrusion injury of tooth with mature root
Spontaneous re-eruption is unpredictable/unlikely
Carry out immediate orthodontic extrusion over 2-3 weeks
Carry out RCT
35
What percentage of intruded teeth will exhibit root resorption
58-70%
36
How long does it take for ankylosis to occur following injury
5-10 years
37
Define avulsion
Total dislocation of tooth from socket
38
Define the most common injury in primary dentition and why it is most common
Avulsion as root development incomplete and periodontium is very resilient
39
2 features avulsion healing depends on
Length of extra-alveolar period
Storage of the tooth out of the socket
40
2 contraindications to avulsion re-implantation
Gross caries of tooth
Major loss of periodontal support
41
Management of avulsion injuries if out of mouth < 1 hour and stored in suitable medium (saliva, milk, saline)
Replant tooth with gentle finger pressure
Splint non-rigidly for 1 week
Antibiotic therapy
42
Management of avulsion injuries if out of mouth > 1 hour
Remove necrotic PDL
Extirpate the pulp at chairside and obturate with GP
Rinse root with saline and replant
Splint for 4 weeks
43
2 types of root resorption
Inflammatory (internal or external)
Replacement
44
Describe the radiographic appearance of external root resorption
Asymmetrical radiolucent shape of surface of root with intact root canal walls
45
Describe the radiographic appearance of internal root resorption
Ballooning of root canal with intact root surface
46
2 managements of inflammatory root resorption
Mechanical and chemical debridement, dress with hypocal, once cessation of resorption RCT
Extract tooth
47
Define ankylosis
Progressive resorption of tooth structure and its replacement with bone
48
Define dental caries
Demineralisation of the inorganic portion and destruction of the organic enamel, dentine and cementum of the tooth driven by the activity of plaque bacteria
49
4 factors required for dental caries
Microbial cariogenic bacteria
Dietary fermentable carbohydrates
Tooth environment
Time
50
What pH does demineralisation of tooth substance occur
Below 5.5
51
5 surfaces particularly susceptible to dental caries
Enamel pits and fissures
Enamel below contact points
Exposed root surfaces
Defective restoration margins
Adjacent to prostheses
52
3 caries protective factors
Good saliva flow
Fluoride
Antibacterials
53
3 systemic effects of fluoride during tooth formation
More rounded cusps
Shallow fissures
Less acid soluble enamel due to fluorapatite formation
54
3 topical effects of fluoride
Inhibits bacterial glycolysis and acid production
Prevents demineralisation
Encourages early caries remineralisation
55
Concentrations of available fluoride toothpastes
6+ years, low risk: 1450ppm (0.312%)
12+ years, high risk: 2800ppm (0.619%)
16+ years, high risk: 5000ppm (1.1%)
56
Concentrations of available fluoride mouthwashes
10+ years, daily: 225ppm (0.05%)
10+ years, weekly: 920ppm (0.20%)
57
Concentration of fluoride varnish
22600ppm (2.26%), applied 2-4 times yearly
58
Concentration of Chlorhexidine products
0.06% mouthwash (twice daily)
0.2% mouthwash (weekly)
1% varnish
59
3 features of the mechanism of action of Chlorhexidine
Disrupts bacterial cell membranes
Inhibits plaque formation
Exhibits substantivity
60
2 features of Triclosan in toothpastes
Bacteriostatic
Broad spectrum
61
1 feature of Xylitol in sugar free gums
Reduces levels of Strep mutans
62
5 consequences of salivary gland hypofunction
Reduced remineralising action
Reduced buffering capacity
Reduced antibacterial action
Increased Candida growth
Risk of mucosal breakdown
63
2 salivary gland stimulants
Sugar-free gum and sweets
Pilocarpine pharmacological sialogogue
64
3 saliva replacements
Saliva Orthana
Biotene
BioXtra
65
4 stages of caries progression
Early enamel caries
Active infected dentine caries
Affected dentine caries
Arrested caries
66
3 objectives of caries removal
Remove infected dentine
Preserve as much tooth substance as possible
Avoid pulpal damage
67
3 caries removal strategies
Complete
Selective one-step
Selective step-wise
68
Describe risk associated with complete caries removal
Higher risk of pulpal exposure
69
Describe the marginal caries clearance required for success of partial caries removal
1 – 2mm margin of hard sound dentine required to achieve sufficient peripheral seal
70
Reduction in pulp exposure seen with stepwise selective caries removal
55% fewer pulpal exposures
71
Describe the 5 stages of stepwise caries removal
Remove coronal caries from walls and EDJ before the floor
Ensure carious dentine over pulp is leathery but not soft
Cover leathery affected dentine with setting calcium hydroxide and restore with GIC
Leave 3 months for tertiary dentine formation
Remove GIC and remove affected caries to firm hard dentine then line and place definitive restoration
72
Reduction in pulp exposure seen with one step selective caries removal
77% fewer pulpal exposures
73
Describe 2 stages of one step selective caries removal
Place RMGIC liner over affected dentine
Placement of permanent restoration
74
Describe the atraumatic restorative technique
Minimally invasive approach which involves removal of caries using hand instruments alone and the placement of an adhesive restoration e.g. GIC
75
Describe the reason for providing cuspal coverage
Directs occlusal forces internally to stop flexure and reduce risk of fracture in RCT posterior teeth
76
Describe a tooth indicated for cupsal coverage with an adhesive restoration
Tooth with only occlusal or <2 walls/cusps lost (<50% tooth)
77
Describe a tooth indicated for cupsal coverage with a crown/onlay
≥ 2 cusps/walls lost (>50% of tooth)
78
3 zones in caries progression
Zone of destruction with dentine decomposition, discolouration with severe breakdown of tooth structure
Zone of penetration
Zone of demineralisation deepest part in the lesion, bacteria free
79
Describe the pulp dentine complex reaction to caries
As the lesion progresses closer to the pulp, the pulp begins to get inflamed will mounts a defence reaction with tubular sclerosis and lays down tertiary dentine
80
Describe the direction of progression of root caries
Caries spread laterally
81
Describe the rate of progression of root caries
Slower rate due to fewer dentinal tubules than in crown area
82
3 managements of root caries
5000ppm fluoride toothpaste
Fluoride varnish applications
Restoration with GIC if cavitated
83
5 indications for composites
Class 1 and 2 cavities small/medium size
Tooth wear
Core build-up
Veneers
Lab-made composite inlays and onlays
84
3 advantages of composites
Conservation of tooth structure
Strengthens restored tooth
More aesthetic
85
3 disadvantages of composites
Technique sensitive
Poorer longevity compared to amlagams
Risk of secondary caries due to polymerisation shrinkage
86
Placement technique for composites
Incremental layering placement where composite is obliquely packed in layers
87
4 advantages of amalgam
High compressive strength
Good longevity
Moisture tolerant
Reduced microleakage
88
3 disadvantages of amalgam
Low tensile strength, weak in thin sections
Does not adhere to tooth structure
Release mercury vapour when polishing
89
3 indications for amalgam
Large posterior restorations with high occlusal forces
Cavities where moisture control likely to be difficult
Core material
90
5 requirements of amalgam preparations
2mm occlusal-gingival thickness of amalgam
No unsupported enamel 90° cavosurface angle
Break proximal contacts
Adequate retention and resistance form
Flat occlusal floor
91
Describe bonded amalgam restorations
Technique of using adhesive to bond amalgam to cavity
92
2 clinical indications for bonded amalgam cavities
Large multi-surface cavities
Amalgam repairs
93
3 advantages of bonded amalgam restorations
Increased amalgam retention
Conservation of tooth structure
Reduced microleakage
94
3 disadvantages of bonded amalgam restorations
Bond may breakdown over time
Uniform placement of bond on cavity walls is difficult
Longer chairside time
95
4 causes of amalgam failure
Recurrent caries (5-50%)
Marginal ditching
Excessive creep
Bulk fracture
96
3 contraindications to amalgams
Confirmed allergy to mercury
Pregnancy/breast feeding
Patients under 15 years
97
6 indications for glass ionomer cements
Deciduous teeth
Class III, Class V cavities
Core build-up
Fissure sealant
Liner
Luting cement
98
2 advantages of glass ionomer cements
Moisture tolerant
Fluoride release
99
4 disadvantages of glass ionomer cement restorations
Prone to fracture
Low flexural strength
Low wear resistance
Need 24 hours before polishing
100
Describe the mechanism of adhesion to tooth substrate of a glass-ionomer cement
Ionic bond between calcium in the enamel/ dentine and carboxyl ions in the GI
101
Describe the mechanism of fluoride release of a glass-ionomer cement
High initial release followed by rapid reduction
Fluoride varnishes may replenish GI fl supply for re-release
102
Describe the setting reaction of glass-ionomer cement
An acid-base reaction
103
3 advantages of adhesive techniques
Good retention and stability
Reduced microleakage
More conservative
104
Describe the mechanism behind enamel bonding
Bond to surface irregularities created by etching allows resin tags to interlock with the enamel surface
105
Describe the requirement of dentine bonding
Requires primer and bond after etching to bond with collagen in dentine
106
Describe wet dentine bonding
Dentine surface should be kept moist but not wet after etching as over-dried dentine leads to the collagen collapse
107
Describe the smear layer
Layer covering the dentinal tubules, composed of
cut dentine debris and bacteria produced by instrumentation that reduces dentine permeability
108
3 advantages of etch and rinse (2 or 3 bottle)
High bond strength
Predictable
Good long-term data
109
3 disadvantages of etch and rinse (2 or 3 bottle)
Extra step
Potential to over-etch dentine
Degree of ‘wetness’ important
110
4 advantages of self-etch (2 or 1 bottle)
No need to etch with phosphoric acid
No rinsing
Reduction in post-op sensitivity
Not so technique-sensitive
111
3 disadvantages of self-etch (2 or 1 bottle)
Enamel requires preparation
Lower bond strengths, but sufficient in most situations
May inhibit set of dual-cure composites
112
5 advantages of shaping and polishing restorations
Minimise plaque accumulation around margins
Minimise surface roughness to limit staining
Maximise aesthetics of the restoration
Harmonise the restoration with the occlusion
Removal of the oxygen inhibition layer
113
Define the oxygen inhibition layer
Soft, sticky, uncured layer that forms after light curing composite as oxygen in the air interferes with the polymerisation reaction
114
Define toothwear
Surface loss of dental hard tissues from causes other than dental caries, trauma or as a result of developmental disorders
115
4 methods of recording toothwear
Study models
Putty index
Photographs
Tooth wear indices
116
Define physiological toothwear
Natural toothwear that occurs due to aging
117
Define pathological toothwear
Rate of wear is greater than that expected for the patient's age
118
Define attrition
Loss of tooth substance by means of friction caused tooth or restoration contact during function
119
Clinical features of attrition and where it is commonly seen
Sharp, well-defined, interdigitating areas of tooth
Commonly of incisal edges in anterior teeth
120
Define abrasion
Loss of tooth tissue by means of friction caused by contact of the tooth with an exogenous agent to the mouth
121
Clinical features of abrasion and where it is commonly seen
V-shaped notching buccal cervical aspect anterior teeth
Commonly on canines / premolars
122
Define abfraction
Loss of cervical tooth tissue in areas of stress concentration
123
Clinical features of abfraction
Wedge shaped defects with sharp rims cervical aspect of teeth
124
Define erosion
Loss of dental hard tissue as a result of a chemical process not involving bacteria
125
2 clinical features of erosion
Smooth concave enamel / dentine
Cupped lesions
126
Common site of extrinsic erosion
Labial surfaces of teeth
127
Common site of intrinsic erosion
Palatal surfaces
128
3 extrinsic causes of tooth erosion
Citrus fruits
Vinegar
Carbonated drinks
129
2 intrinsic causes of tooth erosion
GORD
Eating disorders
130
Define BEWE
Basic erosive wear examination that records the most severely affected tooth in each sextant
131
4 BEWE grades
0: No erosive toothwear
1: Initial loss of surface texture
2: < 50% hard tissue lost
3: ≥ 50% hard tissue lost
132
3 aims of prevention strategies for toothwear management
Reduce frequency and severity of acid attacks
Enhance oral defence mechanisms
Protect susceptible surfaces
133
3 methods to minimise severity of acid attacks
Use straws
Don’t swish, froth or sip
Don’t drink at bedtime
134
3 methods to increase resistance to acid attacks
Fluoride mouthwash
Desensitising toothpastes
Tooth mousse delivered in modified bleaching trays
135
3 methods of providing mechanical protection to teeth
Direct composite restoration
Splint therapy
Dentine bonding agents
136
3 treatment options for localised toothwear
Traditional prosthodontics
Traditional restorations
Dahl concept
137
Describe the Dahl concept
Creation of inter‐occlusal space through axial movement of the teeth by leaving restorations high
138
3 clinical contraindications to the Dahl concept
Gross Class III malocclusions
Lack of eruptive potential
TMD
139
3 intervention managements for tooth erosion
Instruction on reducing frequency and severity of acid attacks
Provision of fluoride to enhance resistance to acid attack
Provision of mechanical protection to teeth
140
3 treatment options for generalised toothwear
Direct restorations
Indirect restorations
Surgical crown lengthening with osseous re-contouring
141
2 indications for surgical crown lengthening
No loss of OVD
Limited inter-occlusal space
142
Define occlusion
Static contact between one or more of the lower teeth and one or more upper teeth
143
Define articulation
Dynamic, gliding contact between one for more lower teeth and one for more upper teeth
144
4 requirements for occlusal stability
Sufficient number of posterior contacts to maintain OVD
Occlusal stops for all teeth
Contact points
Cuspal locking
145
Define intercuspal position
Occlusal position in which the greatest number of contact occur between the upper and lower teeth
146
4 problems caused by occlusal instability
Fracture or wear of teeth/restorations
Debonded crown/bridgework
Mobility of teeth
Temporo-mandibular joint dysfunction
147
Describe 4 features of ideal occlusion
Simultaneous stable bilateral tooth contacts
Disclusion of posterior teeth upon lateral and protrusive mandibular movements
Anterior teeth disclusion when posterior teeth in maximum intercuspation
Canine guidance with no WSI or NWSI
148
4 clinical signs of parafunction
TMJ click, pain
Hypertrophy of the muscles of mastication
Linea alba
Tongue scalloping
149
Describe the conformative approach to restorations
Aims to leave the occlusion with no additional interferences and the occlusion stable
150
3 indications for reorganisation of the occlusal scheme
Unstable ICP
Complete dentures
Protecting and restoring a worn dentition
151
Describe the clinical technique for taking an impression of an indirect restoration
Ensure sufficient gingival retraction
Dispense light body material around crown prep margins
Dispense heavy bodied PVS material into prepared stock tray and seat tray over light body material
152
Describe 4 features of ideal impressions
Sufficient impression detail
Good blend with heavy and light body
Strong bond between material and tray
No tooth contact with the tray
153
Give 5 impression errors
Lack of impression detail
Voids on the prep margin
Tearing at the prep margin
Tray tooth contact
Delamination
154
3 causes of lack of impression detail
Saliva/blood around the prep
Inadequate retraction of gingival sulcus
Excessive working time
155
4 causes of inhibited or slow setting impression material
Contamination with latex gloves
Residues from temporary cements
Inadequate mix
Incompatible light and heavy body materials
156
3 causes of voids on the prep margin
Air trapped in light-bodied syringe
Inadequate coverage of margins with light-bodied material
Blood and saliva contamination around the prep
157
2 causes of tearing at the margin
Inadequate mix
Insufficient retraction
158
2 causes of tray tooth contact
Insufficient impression material
Incorrect size of tray used
159
2 causes of delamination
Long working time
Light body and heavy body materials incompatible
160
2 causes of poor bond of impression to tray
Incompatible tray adhesive used
Inadequate drying time
161
2 gingival retraction options
Gingival retraction cord
Retraction paste
162
Define gingivoplasty
Reshaping of gum tissue around teeth
163
Define gingivectomy
Surgical removal of gum tissue or gingiva
164
4 indications for gingival electrosurgery
Lengthen the crown of a tooth
Gain adequate access to sub gingival caries
Remove localised hyperplastic fibrous gingiva
Control localised bleeding when recording impressions for crown and bridgework
165
3 contraindications to gingival electrosurgery
Very narrow width of attached gingiva present
Large amounts of tissue require removal
Pacemaker wearer
166
2 active components used for tooth whitening
Hydrogen peroxide
Carbamide peroxide
167
Define extrinsic discolouration and 2 common causes
Pigment molecules deposited on tooth surface within pellicle
Smoking and diet
168
Define intrinsic discolouration and 2 common causes
Pigment molecules deposited within bulk of the tooth
Systemic or genetic
169
4 risks of tooth whitening
Sensitivity
Gingival irritation
Altered taste sensitivity
White spots
170
2 potential causes of discolouration of teeth as they age
Physiological change
Cumulative extrinsic stains
171
3 potential causes of discolouration of non-vital teeth
Breakdown of blood pigments within non-vital teeth
Medications and materials used during root canal treatment
Coronal leakage of amalgam restorations
172
2 requirements prior to non-vital bleaching
Good root canal treatment with intact coronal seal
No radiographic/clinical evidence of disease
173
Describe the walking bleach technique for non-vital teeth
Sodium perborate and water delivered internally and sealed with temporary filling
Evaluated after 1 week
174
Describe the inside-outside technique for non-vital teeth
10% Carbamide peroxide delivered
Internally with dispensing syringe
Externally with whitening tray
175
Describe night guard vital bleaching
At home tray delivery in soft tray, 1mm thickness with scalloped edges
10% Carbamide peroxide gel (2-4 hrs) or Hydrogen Peroxide (30-60 mins)
176
Describe the longevity of tooth whitening
Minimum 1 – 3 years but can last as long as 10 years
177
4 indications for surgical endodontics
Iatrogenic or developmental anomalies prevent non-surgical root canal treatment
Non-surgical root canal re-treatment cannot be undertaken or has failed
To facilitate biopsy of peri-radicular tissue
Allow visualisation of the peri-radicular tissues and tooth root when perforation/fracture is suspected
178
4 contraindications to surgical endodontics
Unusual bony or root configurations
Lack of surgical access
Possible involvement of neurovascular structures
Poor supporting tissue
179
Describe the 6 steps in surgical endodontic procedure
Cut muco-periosteal soft tissue flap
Bone removal
Curretage
Root-end preparation of 3mm
Root-end filling: biodentine, root MTA
Suture closure
180
4 potential outcomes following surgical endodontics
Successful: no clinical symptoms, normal periodontal ligament width radiographically
Incomplete: no clinical signs or symptoms, partial regeneration of apical bone
Uncertain: vague symptoms, partial regeneration of apical bone
Unsuccessful: presence of signs or symptoms of periradicular disease, no regeneration of periapical bone
181
3 options for replacing missing teeth
Removable prostheses
Fixed prostheses
Dental implant
182
3 advantages of implants
Perserve alveolar abone
Longevity
No preparation of abutment teeth required
183
3 disadvantages of implants
Requires good quality and quantity of alveolar bone
Risk associated with surgical procedure
Lengthy treatment
184
4 benefits of replacing missing teeth
Restore function: chewing, eating, speech
Improve aesthetics
Prevent tooth movement
Improve occlusal stability
185
Describe the shortened dental arch concept
Aims to provide 10 occluding pairs of teeth based on the concept that it is not necessary to replace all missing natural teeth, particularly posteriorly
186
Describe a crown
Extracoronal, fixed restoration made in the dental lab
187
5 indications for crowns
Strengthen remaining tooth structure
Restore occlusal form
Improve tooth aesthetics
Restoration of endodontically treated teeth
Retain a prosthesis (bridge/partial denture)
188
3 effects of endodontic treatment
Changes in tooth architecture after access cavity preparation
Changes in properties of dentine due to collagen depletion
Changes in proprioception, increasing pain threshold in non-vital teeth
189
2 reasons to provide temporary restorations during endodontic treatment
Support for weakened cusps
Provide good coronal seal to seal access cavity
190
4 reasons crowns are used to restore endodontically treated teeth
Teeth tend to be more likely to fracture
Teeth require cuspal coverage
Large amounts of tooth tissue lost
Teeth often discoloured
191
4 contraindications for crowns
Presence of pulpal pathology
High incidence of caries
Uncontrolled periodontal disease
Very short clinical crown
192
5 potential errors in crown preparation
Sharp internal line angles
Inadequate surface reduction
Over preparation of teeth
Non-uniform shoulder
Undercuts present in tooth preparation
193
1 advantage of all ceramic crowns
Excellent aesthetics
194
5 indications for all ceramic indirect restorations
Veneers
Anterior crowns
Posterior crowns with light occlusal contacts
Anterior bridges
Inlays/onlays
195
4 contraindications for all ceramic crowns
Very deep subgingival restorations
Severely reduced dentitions
Abutments for cobalt-chrome dentures
Bruxism
196
Tooth preparation required for all ceramic veneer
Labial reduction 0.5mm
197
Tooth preparation required for all ceramic crown
Incisal reduction 1.5-2mm
Labial reduction 1-1.5mm
Palatal/lingual reduction 1-1.5mm
198
4 indications for metal ceramic crowns
Anterior teeth
Teeth restored with a cast metal post
Posterior crowns where aesthetics is important
Crown as part of a conventional bridge
199
2 disadvantages of metal ceramic crowns
Excessive tooth preparation
Excessive wear of teeth opposing porcelain surfaces
200
3 advantages of metal ceramic crowns
Improved strength compared to porcelain
Improved aesthetics
Less descructive than all ceramic
201
Tooth preparation required for metal ceramic crown
Incisal reduction: 2.0 mm
Labial reduction: 1.5 mm
Palatal/lingual reduction: 0.5 mm
202
Survival rate of metal ceramic crowns
97% after a period of ten years
203
Describe the method of providing a odus pella temporary crown
Select and trim odus pella crown form
Vaseline crown prepration
Fill odus pella with temphase, ensuring the applicator tip is stays within the material to avoid bubbles
Seat the filled odus pella on the crown preparation
Remove the odus pella, when the temphase is still slightly plastic and coat margins with temp-bond temporary cement and reseat on preparation
204
Describe the method of providing a temporary crown using putty
Take a putty impression of the tooth before any preparation
Fill the tooth putty impression with temphase and seat onto the preparation
Remove the impression, when the temphase is still slightly plastic and coat margins with temp-bond temporary cement and reseat on preparation
205
3 indications for full metal crowns
Heavily restored tooth
Root-filled tooth
Tooth abutment for a partial denture
206
5 advantages of full metal crowns
Requires less tooth reduction
Can incoropate rest seats and guide planes
Margins not complicated by facing materials
Good long term success rates
High strength
207
1 disadvantage of full metal crowns
Poor aesthetics
208
Tooth preparation required for all metal crown
Incisal/occlusal reduction 1mm
Functional cusp reduction 1.5mm
Buccal reduction: 0.5mm
Palatal/lingual reduction: 0.5mm
209
3 crown preparations requiring a chamfer margin
Full metal crowns: all margins
Metal/ceramic crowns: palatal/lingual margin
Bridges: palatal/lingual margin
210
Method of post preparation
Use of non-end-cutting rotary instrumentation, immediately after canal obturation to enlarge canal
and retain minimum of 4-5 mm of Gutta Percha
211
Canal enlargement specifications required for post preparation
Diameter 1/3 root width or less
Length at least equivalent to crown height
212
Problem with insufficient post preparation width
Insufficient strength for long term survival
213
Problem with excessive post preparation width
Increases the risk of perforation and root fracture
214
4 options when insufficient coronal tooth tissue for a ferrule
Accept poorer prognosis
Orthodontic extrusion of root
Crown lengthening
Extract and replace with bridge or implant
215
Describe the benefit of metal and fibre post provision
Provide anchorage for a core upon which a indirect restoration can be placed
216
2 indications for posts
Damage to the crown of a tooth to the extent that a conventional restoration is not attainable
Loss of coronal portion of a root-filled tooth
217
Describe the ferrule effect
Engaging the supra-marginal dentine of a root filled tooth around a crown creates a stronger tooth/restoration complex and to guard against longitudinal fracture
218
How is a ferrule achieved
Parallel walls of 1-2mm of dentine coronal to the shoulder of the preparation
219
Advantage of using parallel sided posts
More retentive
220
3 advantages of metal posts
Can compensate between the angulation of the root and crown
Don’t have the potential for separation from core
Strength
221
3 disadvantages of metal posts
Risk of root fracture
Aesthetics, alter the optical properties of an all ceramic crown
Potential for corrosion
222
Material for cementing cast metal posts and core
RMGI cement
223
Material for cementing fibre posts and core
Composite resin cement
224
2 indications for fibre posts
Aesthetics
Posts for ceramic crowns
225
3 advantages of fibre posts
Reduce the incidence of fractures
Evenly distribute mechanical stresses
Managed at chair-side, impressions are not necessary
226
1 disadvantage of fibre posts
Need sufficient coronal dentine
227
5 reasons for post failure
Caries
Endodontic failure
Root fracture
Perforation of root
Debonding/decementation
228
Define a bridge
Extracoronal, fixed restoration, made in the lab which utilises abutment teeth to replacing a missing tooth
229
5 assessments required before provision of fixed prosthodontics
Tooth restorability
Static and dynamic occlusal assessment
Periodontal and alveolar bone assessment
PAP
Assessment of abutment teeth
230
Describe adhesive bridgework
Minimally invasive bridge which relies on adhesive agents bonding to adjacent teeth for bridge retention
231
Describe conventional bridgework
Crowns are placed on abutment tooth/teeth to retain the bridge
232
Describe Ante's Law for conventional bridgework
The root surface area of the abutment teeth has to equal or surpass that of the teeth being replaced with pontics
233
2 designs of conventional bridgework
Fixed-fixed: 2 abutument teeth
Cantilever: 1 abutment tooth
234
3 requirements prior to the provision of conventional bridgework
Good quality study models
Interocclusal record mounted on articulator
Clinical photographs
235
5 contraindications to conventional bridges
Uncontrolled periodontal disease
Non-functional tooth
Very long spans
Very short clinical crown
Abutment tooth restored with post and crown
236
1 advantage of conventional bridges
Increased lifespan
237
2 disadvantages of conventional bridges
Destructive preparation required
Risk of pulp damage
238
Tooth preparation required for metal ceramic conventional bridges
Incisal reduction: 2.0 mm
Labial reduction: 1.5 mm
Palatal/lingual reduction: 0.5 mm
239
Tooth preparation required for all ceramic conventional bridges
Incisal reduction: 2.0 mm
Labial reduction: 1.5 mm
Palatal/lingual reduction: 1.5 mm
240
3 indications for resin bonded bridges
Short spans
Unrestored or very minimally restored abutment teeth
No evidence of bruxism
241
4 requirements for resin bonded bridge provision
Sufficient enamel available for bonding
Short span
Sufficient interocclusal space
Non-bruxism patient
242
3 advantages of resin bonded bridges
Conservation of tooth structure
Affordable
Easy to replace
243
2 disadvatages of resin bonded bridges
Metal wings was be visible and compromise aesthetics
Shorter lifespan
244
Tooth preparation required for resin bonded bridges
Palatal/lingual reduction: 0.5mm
Anterior teeth: cingulum rest
Posterior teeth: mesial and distal rests
245
Ideal bridge retainer wing coverage
180° wraparound retainers
Full palatal/lingual coverage
Margins at least 1mm above the gingival margin
246
Minimum thickness of resin bonded bridge retainer wing
0.8 mm Nickel-Chromium
247
2 managements for bridge debonding
Recement, indicated if a one off event such as trauma has resulted in decementation
Replacement bridge, higher success rate
248
3 functions of bridge pontics
Improve appearance
Stabilise the occlusion
Improve masticatory function
249
3 factors to consider when designing bridge pontics
Cleansability
Appearance
Strength to withstand occlusal force
250
3 design features of required to ensure adequate cleansability of a bridge pontic
Smooth
Highly polished
Should contain no clear junctions between materials
251
Describe a ridge lap pontic
Fully contoured pontic on the buccal and lingual surfaces to fully fill the available space
252
1 advantage of a ridge lap pontic
Aesthetics
253
1 disadvantage of a ridge lap pontic
Very difficult to clean and maintain
254
Describe modified ridge lap pontic
Full contour on the buccal side only, material is cut away on lingual side to provide cleansibility
255
2 advantages of a modified ridge lap pontic
Aesthetics
Increases hygienic access to gingiva of pontic
256
1 disadvantage of a modified ridge lap pontic
Increased possibility of food entrapment
257
Describe a hygienic pontic
3mm access under the pontic for hygiene
258
2 advantages of a hygienic pontic
Access for hygiene
Decreases the possibility of food entrapment
259
1 disadvantage of a hygienic pontic
Poor aesthetics
260
Describe inlays
Indirect restorations, made in the laboratory for small to moderate cavities
261
Describe an ovate pontic
Egg-shaped end that protrudes into a concavity in the edentulous tissue
262
1 advantage of an ovate pontic
Superior aesthetics
263
2 disadvantages of an ovate pontic
Requires a wide ridge and adequate thickness of soft tissue
More difficult to keep clean
264
Describe a bullet pontic
Pointy area which contacts the gingiva
265
2 advantages of a bullet pontic
Increased hygienic access
Can be used against a variety of ridges
266
1 disadvantage of a bullet pontic
Decreased aesthetics due to lack of full contour
267
6 complications after conventional bridgework provision
Caries
Loss of vitality of abutment teeth
Loss of retention
Periodontal disease/mobility of abutment teeth
Tooth fracture
Prosthesis fracture
268
Describe onlays
Indirect restorations, made in the laboratory for large cavities requiring cuspal replacement/protection
269
Describe why luting cements are used
Fill the void at the interface between the restoration and tooth
270
3 indications for inlays/onlays
History of direct restoration failure
Expected difficulties in achieving an acceptable contour, contact point or occlusion with a direct restoration
Cuspal protection
271
4 advantages of inlays/onlays
Supra-gingival finishing lines
Contact point control
Improved marginal integrity
Less destructive prep than a full crown
272
1 disadvantage of inlays/onlays
Increased chair time
273
Tooth preparation required for an inlay
Central fossa: 1.5 -2 mm
Cavity with <10 degree tapered walls to avoid undercuts
274
Tooth preparation required for a metal onlay
Occlusal reduction: 1mm
Isthmus: 1mm depth
Proximal box: 1mm wide
275
Tooth preparation required for a ceramic onlay
Occlusal reduction: 1mm
No sharp angles
276
4 causes of inlay/onlay failure
Caries
Endodontic complications
Crack/chipping
Loss of retention
277
4 indications for veneers
Masking discolouration/intrinsic staining
Enamel hypoplasia
Changing shape of teeth
Reduce spacing/diastemas between teeth
278
2 contraindications to veneers
Heavily restored teeth, or where no enamel is available for bonding
Guiding teeth
279
3 materials for constructing veneers
Composite resin: direct or indirect technique
Feldspathic porcelain
Pressed ceramics
280
3 factors increasing the retention of cemented restorations
6° degree of taper
Increased tooth surface area
Not over smoothed surface texture
281
3 ideal properties of a luting cement
Good adhesion to tooth and restoration
Possess sufficient working time
High tensile and compressive strength to resist functional forces
282
5 types of luting cements
Zinc phosphate
Glass ionomer
Resin modified glass ionomer
Resin luting cements
Self-adhesive resin luting cements
283
1 advantage of glass ionomer luting cements
Adequate compressive strength
284
4 disadvantages of glass ionomer luting cements
Not suitable for ceramic crowns
Slower set
Moisture sensitive
Doesn’t adhere to restorations
285
2 advantages of resin modified glass ionomer luting cements
Fluoride release
Low solubility
286
2 disadvantages of resin modified glass ionomer luting cements
Moisture sensitive
Doesn’t adhere to restorations
287
3 advantages of composite resin luting cements
Low solubility
Highest compressive and tensile strength
Adhesion to tooth via a dentine bonding agent
288
3 disadvantages of composite resin luting cements
Moisture sensitive
Difficult to remove excess cement
May require a dentine bonding agent
289
3 advantages of self-adhesive resin luting cements
Less technique sensitive
Reduced post-op sensitivity
No discolouration
290
3 properties of Nexus luting cement
Composite resin luting cement
Tooth coloured, improving aesthetics
Dual cure (light and and self cure)
291
Indications for Nexus luting cement
Ceramic inlays, onlays and crowns
292
2 properties of Rely-X luting cement
Self-adhesive resin luting cement
Light cure
293
Indications for Rely-X luting cement
Veneers, thin inlays and onlays
294
3 properties of Panavia luting cement
Composite resin luting cement
Opaque, avoids shine through
Self cure
295
Indications for Panavia luting cement
Metal based restorations, crowns, resin bonded bridges, posts
296
6 things to be included on a resin bonded bridge prescription to lab
Metal wing: Nickel Chromium
Sandblasting with 50um alumina on fitting surface
Thickness: minimum 0.8mm
Full palatal coverage
Occlusion: light contacts in ICP, none on excursions
Pontic: modified ridge lap for aesthetics and cleansibilty
