Bridgework Flashcards
1
Q
What is the definition of a bridge?
A
A prosthesis which replaces a missing tooth or teeth and is attached to one or more natural teeth or implants
2
Q
What are bridges used for?
A
To replace missing teeth
3
Q
What are alternatives to bridges? (4)
A
no treatment, implants, close space with orthodontics or RPD
4
Q
Why should we replace teeth? (3)
A
- Improve aesthetics
- Function– mastication and speech
- Maintaining dental health of other teeth – i.e. tilting of adjacent teeth and overeruption of opposing teeth
5
Q
If a patient needs a tooth replaced and has a greater loss of soft tissue and bone, what is the best treatment option?
A
RPD - can restore gingival contours
6
Q
List the types of bridge designs (7)
A
Adhesive
- cantilever
- fixed-fixed
Conventional
- cantilever
- fixed-fixed
- fixed movable
- hybrid
- spring cantilever
7
Q
What is an adhesive bridge?
A
Where the Pontic is held by wing retainer(s) on abutment teeth
1 wing = cantilever
2 wings = fixed fixed
8
Q
What is a conventional bridge?
A
Where the Pontic is held by a crown retainer(s) on abutment teeth
1 = cantilever
2 = fixed fixed
(can have other designs)
9
Q
What are patient indicators for using a bridge (adhesive or conventional) (6)
A
- Improve aesthetics
- Improve function & stability
- Improve speech
- Psychological reasons
- Systemic disease e.g. epileptic – inhaled removable dentures so need something fixed
- Cooperative patient with good OH, no active disease and motivated
10
Q
What are local indicators for using a bridge (adhesive or conventional) (4)
A
- Large teeth – increases surface area
- Heavily restored – already compromised so ideal esp for conventional
- Favourable abutment angulations
- Favourable occlusion with no heavy contacts on the bridge
11
Q
What are patient contraindications for using a bridge (adhesive or conventional) (5)
A
- Poor cooperation
- Poor OH with active disease (caries and perio)
- Unmotivated
- Medical history – allergies to materials
- Age – esp for conventional bridges, young patients with large pulps
12
Q
What are local contraindications for using a bridge (adhesive or conventional) (8)
A
- High chance or further tooth loss – better with denture
- Poor prognosis of abutment teeth
- Length of the space that requires filled (the fewer the teeth being replaced the better, longer bridges flex more under load)
- Lack of ridge form and tissue form – Denture better at replacing this
- Tilting and rotation of teeth – can make it difficult to seat the bridge and adjust occlusion
- Degree of restoration on the teeth
- PA status – cannot use teeth with active disease as abutment
- Active/advanced perio = poor abutment
13
Q
Define an abutment.
A
A tooth which serves an attachment for a bridge
14
Q
Define a pontic.
A
The artificial tooth suspended from the abutment teeth
15
Q
Define a retainer.
A
The extra-oral/intra-oral restoration that is connected to the Pontic and cemented to the prepared abutment teeth.
16
Q
Define a connector.
A
The component which connects the Pontic to the retainer
17
Q
Define a pier.
A
An abutment tooth which stands between and is supporting 2 poetics being attached to further abutment teeth.
18
Q
Define a unit.
A
Can be a retainer or Pontic
e.g. a bridge with 2 retainers and 1 Pontic = 3 unit
19
Q
Define a saddle.
A
An area of edentulous ridge over which the Pontic will lie.
20
Q
What is a fixed fixed bridge design?
A
A bridge where there are retainers on either side of the pontic(s)
- can be conventional or adhesive
21
Q
Where are fixed-fixed designs commonly used in the arch?
A
Commonly used posteriorly
22
Q
Why are fixed-fixed designs not commonly used anteriorly and why are cantilevers more commonly used?
A
- Anterior teeth in the maxilla have divergent guidance paths
- have different longitudinal axis
- as a result the occlusal forces are directed down the teeth in different ways
- don’t want to cement these teeth together (fixed-fixed) as it can cause “jutting” of the bridge (since the pontic is attached to 2 teeth with occlusal forces going in 2 different directions)
= cause it to fail and debond.
23
Q
What is a cantilever bridge design?
A
Where there is a retainer on one side of the pontic only
- can be conventional or adhesive
24
Q
Where are cantilever designs commonly used in the arch?
A
anteriorly
25
What materials can the wings of adhesive bridges be made from? (3)
Metal - CoCr or NiCr
all ceramic
26
What are the advantages of adhesive bridges? (6)
* Minimal or no tooth preparation
* No LA – since no/little preparations
* Less costly
* Less time in the chair
* Can be used as Provisionals i.e. hypodontia patients to replace teeth before implants
* If bridge fails – no tooth tissue destroyed (compared to crowning etc)
27
What are the disadvantages of adhesive bridges? (6)
* Must have good technique e.g. needs tooth to be dry for cementing etc
* Metal shine through (i.e. along incisa edge) – from poor design or cementing or very translucent incisal edges
* Porcelain of pontic can chip off
* Can debond – recementing = will never have as good a bond as the first time = more likely to fail
* Occlusal interferences – less common in static occlusion these days due to axial tooth movements (DAHL) can be more problematic during dynamic (lateral) movements
* No trial period possible – can only use definitive cements no temps
28
What are the Indications for adhesive bridges? (6)
* Younger teeth – less destructive and won’t interfere with the pulp
* Good enamel quality – since bonding to enamel with resin-based cements
* Large abutment tooth surface area
* Use in sites with minimal occlusal load
* Good for single tooth replacement
* Simplify RPD design
29
What are the contraindications for adhesive bridges? (6)
* Poor quality of enamel
* Longer spans of teeth needing replaces
* Excess soft tissue and hard tissue loss
* Heavy occlusal forces e.g. bruxism
* Poorly aligned, tilted or spaced teeth – problems with path of insertion and aesthetics
* Potentially problematic with contact sports – not a complete Contra-indication, ensure mouthgaurds.
30
What are the types of adhesive bridges (not designs) and when are they used? (2)
1. Direct
- Useful for emergency i.e. after extraction after trauma as they are done chairside on the day
2. Indirect - standard type that requires lab prep and 2 appointments
31
How do we construct a DIRECT adhesive bridge after trauma? (2 ways)
- Use patients own tooth as the pontic
- Alternatives if tooth lost: use acrylic denture tooth, prefabricated polycarbonate crowns or cellulose matrix of tooth shape filed with composite
32
Describe in detail the process of providing a direct adhesive bridge. (6 steps)
1. Cut root off of extracted tooth
2. Remove pulp in crown
3. Place composite over the pump chamber
4. Etch the contacts of the tooth and the “abutment teeth” contacts
5. Reseat the tooth
6. Composite between contacts on both sides and cure in place
33
Describe the requirements for providing an indirect adhesive bridge. (3)
- Need large palatal/lingual coverage to increase surface area
- Need good enamel quality for bonding
- Needs to be 0.5mm above the gingival margin (supragingival)
34
Describe how you would bond an adhesive bridge to a tooth with existing restorations (amalgam and composite)
Bonding to Composite:
- Composite can bond to composite
- If old, maybe replace to increase the bond success
- Roughen the older composite using a slow speed
Bonding to Amlgam:
- Remove amalgam and replace with composite
35
What aspects of a patients history would make you question bridge placement. (2)
bruxism
| contact sports
36
Describe in detail the minimal tooth preparation for an anterior adhesive bridge. (4)
- Nothing
or
- Minimal Occlusal contact reduction (esp in heavy contacts)
- Remove cingulum undercut
- Chamfer margin 0.5mm above margin on the palatal/lingual aspect
37
Describe in detail the heavy tooth preparation for an anterior adhesive bridge. (4)
- 0.5mm thick chamfer margin 0.5mm above the margin
- Reduce entire palatal surface by 0.5mm
- provide Cingulum rest
- provide Proximal grooves
38
Describe in detail the tooth preparation for a posterior adhesive bridge. (4)
- Nothing
- Occlusal rests 2mm deep
- 180 degree wrap around chamfer 0.5mm in depth with finish line 0.5mm above gingival margin
- Proximal grooves
39
What do we temporise adhesive bridge preps with between appointments? (3)
- RPD
- Essex retainer
- No need since prep in enamel – just use Sensodyne/duraphat or thin layer of dentine bonding agent.
40
How do we improve the bond between the bridge components and the tooth?
The fitting surface of the bridge is sandblasted (with aluminium oxide of 50 microns thickness )
to create indentations in which the resin can interlock with to create micro-mechanical retention.
41
What do we recommend to patients for maintaining oral hygiene with a bridge in place.
- Use superfloss to clean beneath the pontic using a sweeping motion
- Use Tepe brushes
42
Name the 5 types of conventional bridges.
- fixed - fixed
- cantilever
- Fixed moveable
- Hybrid (fixed retainer and an adhesive retainer
- Spring cantilever
43
When can fixed-fixed conventional bridges be used anteriorly.
in patients when the anterior teeth are not in occlusion i.e. class 2 relationship or patients with AOB’s
44
What are the advantages of conventional fixed-fixed bridges? (5)
* Robust design – as they are retained by crowns and can use larger connectors = more able to withstand occlusal forces
* Maximum retention and strength – since retained by crowns (mechanical and chemical retention)
* Can use to splint abutment teeth together e.g. stabilising a tooth with severe and arrested perio
* Can use for replacing more teeth/longer spans
* Lab constructed = easy to make
45
What are the disadvantages of conventional fixed-fixed bridges? (4)
• Difficult preparation – have to ensure both abutments are parallel (common path of insertion
- By achieving parallelism = common path of nsertion = increases retention as only one way on and one way off.
* Ensuring the prep is minimally tapered – overtapering reduces the retention (between 5-7 degrees)
* Ensure both abutment teeth have common paths of insertion
* Have to remove tooth tissue to prep – danger to pulp
46
What are the advantages of conventional cantilever bridges? (2)
* More conservative as you only have to prepare one tooth
| * Don’t have to ensure both abutments parallel
47
What are the disadvantages of conventional cantilever bridges? (3)
* Preferred use in single tooth replacement/short spans
* More rigid to avoid distortions = fracture risk
* Ideally want to have a mesial cantilever design (pontic mesial to the abutment) = not always possible
48
Why do we prefer medial cantilever designs and want to avoid distal cantilever design in conventional crowns?
want to avoid distal cantilever
– reason for this is because the first occlusal contacts are usually on more posterior teeth so if pontic is distal to the abutment it can be subjected to leverage forces on the abutment and cause tilting
49
What are the exceptions to avoiding distal cantilever conventional crowns? (2)
- when patients have e.g. 34 to 44 or 35 to 44 and we need to add another tooth in order to create an SDA using a distal cantilever bridge.
- Premolar abutments which are unopposed or opposed by a denture
50
What alternative fixed-fixed bridge designs are available
| when we cannot achieve parallelism of the abutment teeth for a conventional fixed-fixed bridge? (3)
Fixed movable bridge = Comes in 2 parts – Rigid end distally and movable connector mesially
Hybrid bridge = One retainer is a conventional crown and one retainer is an adhesive wing
Spring cantilever = Where one pontic is attached to the end of a metal arm that runs across the palate to a rigid connector on the palatal side of a retainer.
51
What are the pontic’s functions? (3)
- Restoring appearance
- Stabilising occlusion
- Improving masticatory function
52
What must we consider when choosing a pontic? (3)
* Cleanability = ensure smooth and polished surfaces with no joins (metal and porcelain) so plaque cannot adhere and is easily cleansed
* Appearance = Ensure as natural looking as possible (especially anterior)
* Strength= Longer the span the more flexing it undergoes so need a greater thickness to withstand the occlusal forces
53
List the 5 Pontic design choices.
Wash through/hygienic
Dome/bullet/torpedo
Modified ridge lap
ridge lap (full saddle)
ovate
54
List the advantages of a wash through Pontic design. (3)
* Functional as it provides an additional occlusal surface
* Easy to clean
* doesn't contact the alveolar ridge
55
Where would a wash through Pontic design commonly be used in the arch? (1)
lower molars
56
List the advantages of a bullet Pontic design. (2)
* Upper 2/3rds of Pontic = provides natural appearance
| * Lower apical 1/3rd = narrow and less aeathetic howver ensures Pontic is more cleansable
57
Where would a bullet Pontic design commonly be used in the arch? (3)
upper molar
| lower incisor /premolar
58
List the advantages of a modified ridge lap Pontic design.(2)
* Buccal surface = provides natural appearance for aesthetics
* Lingual surface = trimmed/cut away for cleaning
59
List the disadvantages of a modified ridge lap Pontic design. (1)
Since the Lingual surface is trimmed/cut away it can cause food packing
60
List the advantages of a ridge lap Pontic design. (2)
* Has greatest contact with soft tissue = Less food packing than the modified
* Perfect for those who have good OH and are motivated
61
List the disadvantages of a ridge lap Pontic design. (1)
• If prescribed to someone with poor OH = food packing and plaque accumulation below the pontic = gingival inflammation
62
List the advantages of an ovate Pontic design. (2)
* best aesthetic outcome – presses down on gingivae and causes gingivae to mould into a divit (looks like a natural tooth piercing out the gum)
* Perfect for those who have good OH and are motivated
63
What materials are used for conventional bridge designs? (9)
All metal:
- Gold (best)
- Nickle/cobalt chromium (cheaper)
- Stainless steel
Metal ceramic
All ceramic:
- Zirconia e.g LAVA and proceera
- Lithium disilicate e.g. E.max
Ceromeric: Porcelain and composite combined (not used as much)
- Belleglasss
- Vectris
- Targis vectris
64
Where are all metal conventional bridges commonly used? (1)
lower posterior areas
65
What are the advantages of using a metal ceramic material for a conventional bridge? (1)
Halfway between strength and aesthetics
| - Most commonly used/majority of bridges made from this
66
What are the advantages of using an all ceramic material for a conventional bridge? (4)
- Great aesthetics
e. g. LAVA (modern)
- modern ceramics becoming better at withstanding occlusal forces = stronger
- modern ceramics becoming stronger so less width of ceramic is required = less tooth prep
- modern ceramics are milled from blocks with layers of varying colour = natural tooth appearance
67
What materials are used for definitive cementing of all metal conventional bridges? (2)
- Aquacem (GI luting cement)
| - RelyX (RMGI luting cement)
68
What materials are used for definitive cementing of metal ceramic conventional bridges? (2)
- Aquacem (GI luting cement)
| - RelyX (RMGI luting cement)
69
What materials are used for definitive cementing of all ceramic conventional bridges? (1)
- NEXUS kit (dual cured resin cement)
70
What materials are used for definitive cementing of all ADHESIVE bridges? (1)
- Panavia 21 (anaerobic dual cured resin cement with 10-MDP – helps adhere to metal work)
71
Describe what PANAVIA 21 is and when it is used.
anaerobic dual cured resin cement with 10-MDP – helps adhere to metal work
Definitive cementing of all adhesive bridges
72
What is the 5 year prognosis of adhesive bridges?
80.8%
73
What is the 10 year prognosis of adhesive bridges?
80.4%
74
What is the 5 year prognosis of conventional fixed-fixed metal ceramic bridges?
93.8%
75
What is the 10 year prognosis of conventional fixed-fixed metal ceramic bridges?
89.2%
76
What is the 5 year prognosis of conventional fixed-fixed all ceramic bridges?
88.6%
77
What is the 5 year prognosis of conventional cantilever bridges?
91.4%
78
What is the 10 year prognosis of conventional cantilever bridges?
80.3%
79
What is the 5 year prognosis for an implant retained bridge?
95.2%
80
What is the 10 year prognosis for an implant retained bridge?
86.7%
