Resin-retained Bridges Flashcards
Name the 3 types of resin-retained bridge support?
Impant supported
Tooth supported with minimal prep
Tooth supported with heavier prep
Describe the advantages of resin-retained bridgework?
- Minimal, preferably no
tooth preparation - High quality frameworks
- High prosthodontic
standards - Controlled adhesive
techniques
Name the 3 principles to bridges?
Area of coverage
Thickness of retainers
Control of the occlusion
Name 3 types of bridges needing little to no tooth prep?
Cantilever
Fixed-Fixed
Hybrid
Describe what is a Cantilever bridge?
1 or 2 abutments
indicated for short spans generally anterior
all-ceramic resin-retained bridges
Requirements for a Fixed-Fixed bridge?
Framework design must have a retainer thickness of 0.7mm
Control of the occlusion
Approximal guide planes
Maing use of relative axial tooth movement
Occlusal considerations may impact the design
Does tooth prep improve outcome of bridges?
No evidence has been found
When is tooth prep necessary?
when creating guide planes to allow connector height
Describe the framework coverage for resin-retained bridges?
Coverage from incisal
edge up to the wall
apical to the cingulum
* Extension into the
approximal areas
* Maximum mesio-distal
wrap-around
* Minimum 0.7 mm
thickness
Name the best bridge style for post-ortho retention?
fixed-fixed designs for maximal coverage
- cantilevers will not be stable
Proximal contacts will
not provide post-orthodontic stability
What is the classical design for posterior tooth replacement?
Classical design:
180 degrees axial coverage
Rest seats adjacent to the pontic area
Tooth preparation to create guide planes nearly
always essential
Guide planes close to parallel - 6-10 degrees
Occlusal coverage - 0.7mm - provides greater security
Making use of relative
axial tooth movement
What to treate the fitting surface of the bridge with?
Sandblasting with either Ni-Chr or Chr-Co alloys
When to do finishing of the bridge?
only at cermentation visit
if possible delay finishing with roatry instruments for at least 24hrs
What is the definition of a bridge?
A prosthetic tooth replacement that is fixed to at least one natural tooth or dental implant
Name the 4 components of a fixed-fixed conventional bridge?
Abutment tooth
Retainer
Connector
Pontic
Name the 5 aims of restorations?
Aesthetics
Function
Comfort
Occlusal stability
Maintainable
Describe a resin-bonded bridge?
Retainer is a metal wing
Conventional cantilever
Resin retained cantilever bridge
Describe a conventional bridge?
Retainers are usually a full coverage crown
Indications for removable denture (contraindications for fixed protheses)?
Many missing teeth (multiple or longspan) simplifies treatment
Prognosis of remaining teeth
Young patient
Sports player
Gross alveolar resorption
Lack of suitable abutments for bridgework
Midline diastema
Poor patient motivation
Name 5 reasons for a fixed rather than a removable prosthesis?
More acceptable
Does nor cover the gingival margin
Directs forces axially
Restores the occlusal anatomy
Prthodonric retention or periodontal splinting
Describebthe conventional cantilever bridge design?
Pontic is connected to the retainer at one end only
A single retainer more conservative than 2
Leverage imposed on abutment teeth
Suitable for limited span length
Not for use with heavy occlusal forces on the pontic
Name the indications for conventional cantilever?
Short spans generally anterior
How many abutments are necessary for a bridge?
Double abutments can increase the risk of loss of cementation
Why can double abutting be a disaster for bridges?
When pontics flex secondary abutmens are placed in tension and may debond
Sometimes its necessary however the distal wall of the secondary butment should offer very good resistance form
Tensile forces are transmitted to distal retainer
Cemebt failure
Caries of distal retainer
Describe a spring-cantilever bridge?
Obsolete
Describe the conventional fixed-fixed bridge?
Pontic is connected to 2 retainers
Not conservative
Less torque compared with cantilever
Better for longer spans, and heavy occlusal loads
Significant biomechanical and biological issues
Explain the requirements for a fixed-fixed conventional bridge?
All joints are soldered or cast in one piece to connect all abutment teeth
Requires good retention at either end of soab
Preps must be parallel
Single path of insertion and removal
How can taper affect the bridge retention?
An increase in taper leads to decreased resistance form and increased stress on the cement lute
Describe the occlusal forces for a bridge?
The direction of occlusal forces is dependant on position in the arch
Distance and direction of tooth movement during function translate to stress on lute
In fixed-fixed designs each abutment should provide equivalence of retention
What are the risks associated with fixed-fized designs?
Decementation of the retainer
Why does a fixed-fixed bridge need more resistance form?
Due to the rotational arc of displacement is increased
Describe fixed-movable designs of a bridge?
Short spans
Alignment of abutments
Quality of abutments
Independent mobility of teeth
Advantage for short posterior spans
A stress breaker
Angled abutments
Provisions for failure
Needs modification to tooth prep
Name the different types of retainers?
3/4 gold crown
Full veneer crown
- gold
- mcc
- ceramic
Describe the Shillingberg’s principles of tooth prep
Preserve tooth structure
Structural durability of restoration
Retention and resistance form
Marginal integrity
Preservation of the periodontium
Aesthetics
Name the pros and cons for a 3/4 crown for a retainer in a bridge?
More conservative than a full veneer crown
Retention/resistance porter than full veneer
Structurally weaker due to open face
Modest chamfer and occlusal reduction
Long margin for failure
Supragingival margins
Aesthetics
Name the pros and cons for a full veneer gold crown for a retainer in a bridge?
Requires prep of all coronalmtissue
Very good retention and resistance
Strong structurally
Burnish margins to achieve good adaption
Preserve periodontium
Poor Aesthetics
Name the pros and cons for a metal cermaic crown for a retainer in a bridge?
Requires prep of all coronal tooth tissue
Verg good retention/resistance
Strong structurally
Destructive prep
Preserve periodontium
Good aesthetics
Name the pros and cons for a all ceramic crown for a retainer in a bridge?
Abutments need heavy prep to give greater taper and thicker cermaic layer
Good resistance and retention
Structural durability
Very aesthetic
Name the 4 factors affecting the selection of abutments teeth?
Suitability of patient
Suitability of oral environment Suitability of position of abutment
Suitbailiry of tooth and supporting structures
How to assess the suitabilitybif a patient for a bridge?
MH
PDH
SH
How to assess the suitability of the oral environment?
HT Charting
Peridontal charting
Parafunction
Occlusion
How to assess the tooth for a bridge?
Special tests
Investigations
How to assessnthe suitability of the position of the tooth for a bridge?
Bridge mechanics:
- length of span (Ante law)
Curvature of span
Angulation of teeth
Position of span in arch
How can the length of span affect your bridge?
No more than 2 pontics for fixed fixed and 1 for cantilever
Describe Ante’s Law?
The root surface area of the abutmentntooth should be equal or surpass that of the teeth being replaced with pontics
Why should you avoid long span bridgework?
Flex = stress to abutment and cement lute
Places increases load on PDL
Any bridge replacing more than 2 units high risk
Equation for flexibility?
PL3/
EDW
P - load
L - length
E - modulus of elasticity
D - dimension perpendicular to load
W - dimension laralll to load
How can curvature of the span affect the bridge?
Pontics lying outside of the interabutment axis will act as a lever
How can angulation of a tooth affect the bridge?
To achieve parallelism prep misg be very heavy
Non axial loading of teeth can cause occlusal trauma
Support requirements for an abutment teeth?
Root configuration
- surface area
Length of clinical crown
Crown to root ratio:
- ideal 1:2
- good 2:3
- acceptable 1:1
Why are root filled teeth bridges more likely to fail?
Vulnerable to fracture
- coronal access removes roof of pulp chamber
- canal prep reduces bulk of dentine
- posts even worse
What to assess for an abutment tooth?
Occlusal forces
Integrity of existing restoration
Crown height
Caries
Periodontal support
Pulpnheslth
Endonstatis
Root fillings?
Post and cores?
Periapical status
Crown toot rariib
Describe the ideal occlusion for a bridge?
Posterior stability
incisal/canine guidance
Absence of posterior interference on mandibular movement
Describe what is involved for pontic design?
Ridge lap
Modified ridge lap
Bullet
Ovate
Hygienic
Deacribe a hygienic pontic for a bridge?
Better for perio health, space for flossing
Not aesthetic
Food trapping
Describe a bullet pontic for a bridge?
Wide embrasures to facilitate cleaning
Aesthetic
Non space for food trappibgq
