What are some consequences of tooth loss?
- Over-eruption
- Drifiting/tilting of adjacent teeth
- Caries (due to open proximal contacts)
- Altered occlusion
- Gingival recession/resorption of bone
- Periodontal pocketing
- Food impaction
- Overgrowth of tongue
- Aesthetics comporomsied
What are some reasons for replacing teeth?
- Aesthetics
- Function
- Occlusal stability
What are some treatment options for tooth replacement?
- No treatment
- Implants
- Orthodontic closure
- Orthodontic redistribution
- Removable partial denture
- Fixed prosthesis
- Combination treatments
What can be used to help treatment planning and preparation of bridges?
Diagnostic casts
Trial wax ups
Vacuum form template (index guide for tooth reduction, temporary bridge construction, test tolerance of bridge design appearance and function)
What is a fixed bridge prosthesis definition?
-Any dental prosthesis that is cemented, screwed, mechanically attahced or otherwise securely retained to natural teeth/roots or implants
What are the components of a fixed bridge?
- Abutment: Tooth or teeth that receive the crown/which the bridge is anchored to
- Retainer: Part of bridge that goes over the abutment tooth
- Pontic: Prosthetic tooth or teeth that replace the missing teeth
- Connector: Joint between pontic and retainer
What is a fixed-fixed bridge?
Basically a bridge where the pontic tooth is situated between two abutment teeth
- Uses rigid connectors
- Single piece construction
- Sometimes one connector is soldered
- Can be long or short span
*Occlusal scheme must be optimised to obtain suitable bridge design (e.g. over-eruption of opposing tooth does not allow for good design)
What is the issue with long span fixed-fixed bridges?
-If inadequate support prone to flexure, connector fracture, ceramic or resin facing failure, debonding
What is a cantilever bridge?
Bridges where pontic is attached at one end of the bridge rather than at both
- Abutment can be single tooth or two teeth joined together (latter gives additional support + retention)
- Abutment tooth requires high load bearing capacity
- Retainer usually full crown
What is the best guide as to the number of abutment teeth needed to support a pontic in a cantilever bridge?
-Root surface area of abutment teeth
What is a spring bridge?
A form of cantilever bridge where the bridge retainer/abutment tooth and pontic are not adjacent to each other and are instead joined by a metal connector which overlies the palatal vault
- Useful in diastema situations
- Only single tooth replacement possible
- Usually implants are used instead if space allows
What is a fixed-movable bridge?
A fixed bridge divided into two sections:
- Major distal retainer that is fixed and attached to pontic
- Minor mesial retainer that is connected to a pontic by a distal slot which allows vertical movements
- No bucco lingual movement is allowed
- Movable section acts as stress breaker which reduces torque and functional forces on retainers
What are the benefits can fixed bridges provide?
Functional
- Stability and retention of prosthesis
- Occlusal stability
- Improved function (speech, mastication)
Patient factors:
- Aesthetics
- Confidence
- Comfort
What are the disadvantages of fixed bridges?
Operative factors:
- Invasive procedure
- Failure can be catastrophic
Patient factors
- Cost/repair and replacement cost
- Cleaning and maintenance
Potential unwanted ‘side effects’
- Tooth devitalisation
- Loss of perio support
- Abutment sensitivity
What factors would you take into account during your consult in planning for fixed bridges?
Hx
- Age (if too young occlusion not stabilised)
- Medical status
- Occupation/lifestyle (aesthetics important?)
- Parafunction (want to control before getting into treatment)
Occlusion:
- Enough space?
- Tooth angulations/twistings/crownding/rotations
- Length of edentulous space
Perio: Sufficient support (including crown-root ratio), edentulous ridge form
Hard tissue: caries risk, endo issues, longevity of abutment
What are the indications for a fixed bridge?
Success factors
- RPD or implant not considered suitable
- Good periodontal support for abutments
Pt factors
- Pt prefers fixed option over implant
- Low caries risk
- Capacity to clean and maintain bridge
- Compliance with recall program
Functional factors
- Replacement of a failed bridge
- Restoration of space where coronal restorations of abutment teeth would be of benefit to the patient
What materials are possible for use in bridges?
- Dental alloy (type 4 gold or base metal)
- All ceramic
- Fibre reinforced composite
- Ceramo-metal
- Resin veneered alloy (resin instead of ceramic)
What are the key stages for planning for fixed bridges?
- Patient interview
- Clinical Examination
- Radiographic examination
- Articulated study casts
- Diagnosis
- Treatment options
- Biomechanical factors
What does the patient interview involve?
-Determine needs and expectations
-Assess achievability
-Has patient been to see other dentists?
-Patient factors
(attitude and motivation, oral care, caries risk, saliva, economic)
How should the diagnosis be described?
- Describe the missing teeth and why missing
- Describe state of abutment teeth
What are the treatment options possible for missing tooth replacement?
- Bridge
- RPD
- Implant retained crown
- No treatment
What are the biomechanical considerations in placing a bridge?
- Span length
- Tooth crown: root ratio
- Root configuration
- Root surface area
- Retention of bridge retainers
- Use of secondary abutments
- Pier abutments/complex bridges
- Special cases
What determiens flexure of a bridge?
Flexure directly proportional to D^3 where D is the length of the bridge/space length
What are some factors to consider for retention for bridge retainers?
- Need high retention and rigidity to resist flexion, and able to resist mesio-distal directed dislodging forces
- Limited by weakest retainer
- Secondary abutments can increase retention, but load will be placed on secondary retainers thus must be equivalent to primary abutment
-
PBM and PBZ20
-
Sim Clinic Standardised Measurements4
-
Post and Core75
-
Full Gold Crown10
-
Temporary Crowns17
-
Veneers30
-
Onlays11
-
Bridges_Intro27
-
Resin Bonded Cast Alloy Bridges24
-
Cements51
-
EMAX Crowns29
-
Ceramics and Resins21
-
Soft Tissue Management_Surgery13
-
Aesthetics and Shade Selection10
-
Impressions17
-
E4D CADCAM4
-
Soft Tissue Management_Retraction14
-
Resin bonded Fibre Reinforced Composite Bridges6
-
Fixed PRos For Periodontally Compromised Teeth7
-
Pontics12
