Treatment Planning for Fixed Prosthodontics Flashcards
fixed prosthodontics
the area of prosthodontics focused on permanently attached (fixed) dental prostheses. Such dental restorations are also referred to as indirect restorations
types of fixed prosthodontics (4 main)
Veneers
Inlays and onlays
Crowns
Bridgework
Post and cores – mix fixed prosthodontics and endodontics
history and examination for fixed prosthodontics
Patient complaint (CO)
History of Presenting Complaint (HPC)
Past Dental History (PDH)
Past Medical History (PMH)
Social History (SH)
Family History (FH)
Extra-oral Examination(EO)
Intra-oral Examination (IO)
Lead to provisional diagnosis – problem list and treatment plan deals with this
extra oral exam for fixed prosthodontics
TMJ
Muscles of mastication (MoM)
Lymph nodes
Symmetry
Lips
- Vermillion borders
- Commissures
- Smile line
Prosthodontics is largely aesthetically driven
high smile line
High – teeth zenith exposed
hard prosthodontics
middle smile line
Middle – touch zenith teeth and small interproximal exposed
low smile line
Low – zenith and gingiva covered
ideal for fixed prosthodontics
- less technically demanding
intra oral exam for fixed prosthodontics
Look at whole mouth first before individual teeth
Soft tissues - Buccal mucosa - Tongue Lateral borders Dorsum
Sublingual tissues/Floor of mouth
Palate
- Hard
- Soft
Lips
part of dental examination for fixed prosthodontics
Periodontal
- BPE
Dentition
- Chart teeth
Present and missing teeth
Restorations
Caries
Occlusion - Incisal relationship - Excursions of the mandible (Protrusion; Retrusion; Lateral) Canine guidance? Group function?
inter arch space
inter tooth space (mesio-distal)
special investigations and sensibility tests
what to look for on radiographs for fixed prosthodontics
? Caries
- ? Restorability
? Tooth fractures
- Able to hold prosthodontic?
? Periapical pathology
- Radiolucency – non vital
? Bone levels
- Mobile teeth
- adequate supported as subjected to occlusal loads
Existing large restorations (direct or indirect)
Assessment of potential abutment teeth
study models for fixed prosthodontics
can consider options when pt away
facebow
record the hinge axis of TMJ can be used to mount casts on semi adjustable articulator
- Replicate pt specific occlusion
Maxilla in the relationship with hinge axis
Mandible need occlusal wax bite or jet bite
Especially if tooth involved in guidance
- Canines for canine guidance
- Group guidance – several teeth
Changing anything to do with occlusion
- OVD
- Contact areas
diagnostic wax up
How teeth may function
- Contact spots
- Aesthetics etc
additional information gathered for fixed prosthodontics (5)
Diet diary
Plaque and gingivitis indices
Full mouth periodontal chart
Clinical photographs
Microbiology, biopsy, haematology – rare
4 stages of treatment planning
immediate
initial (disease control)
re-evaluation
maintenance
immediate treatment planning
Relief of acute symptoms
Consider endodontics and extractions
Consider immediate denture/bridge
initial treatment planning
(Disease Control)
Extraction of hopeless teeth
OHI and dietary advice – preventative plan
HPT
Management of carious lesions and defective restorations with direct restorations or provisional restorations
Endodontics
Denture design, wax up for fixed prosthodontics
re-evaluation treatment planning
Re-assessment of periodontal status, confirm denture/bridge design
reconstructive treatment planning
Perio surgery
Fixed and removable prosthodontics
- Final stage – start with OHI and dealing with making oral cavity in a healthy state
maintenance treatment planning
Supportive periodontal care and review of restorations
options for fixed prosthodontics driven by (6)
Dentist
- Best long term? Conservation?
Patient
- Aesthetics? Cost?
- Need a dialogue
Medical Facts
- allergies
Costs
Time
- Indirect – tooth prep, lab stage, fixed stage and additional apps sometimes
Dental Facts
what decisions need to be made about the teeth in Q
Keep the tooth or extract?
If to be kept, what type of restoration?
- What tooth preparation is necessary?
when may extract tooth rather than retain
extensive caries beyond alveolar ridge (cut off point for restorability)
Horizontal fracture through furcation
- Constantly leak and thus fail
- Sore for pt
LL6 has 2 posts (odd) caused a wedging effect and tooth fracture
alternative treatments to fixed prosthodontics (3 main)
Previously traumatised and RCT 21 incisor
- Discoloured
- Want to keep young women off restorative sliding scale
Internal and external bleaching – whitened tooth
large pattern off tooth loss
- Multiple missing posteriors
Bridge unsuitable – need RPD
Implants
- Worth discussing if feasible
preparatory treatment for fixed prosthodontics may include
Endodontic Tx
Hard if previous restorations present e.g. posts impinging on RCS
- Egger device
why place veneers (5)
Improve aesthetics
Change teeth shape and/or contour
Correct peg-shaped laterals
Reduce or close proximal spaces and diastemas
Align labial surfaces of instanding teeth
gurel mimmal preparation technique for veneers
Wax up
Stent
Intra-oral mock up
Preparation into mock up (can use depth cur burs)
when not to use veneers (11)
Poor OH
High caries rate
Interproximal caries and/or unsound restorations
Gingival recession
Root exposure
High lip lines
If extensive prep needed (>50% of surface area no longer in enamel)
- Consider alternatives – PJC, DBCs MCCs (veneers rely on chemical bond – best to enamel so if into dentine need some mechanical retention too)
Labially positioned, severely rotated and overlapping teeth
Extensive TSL/insufficient bonding area
Heavy occlusal contacts
Severe discolouration
why restore teeth with inlays/onlays (5)
Tooth wear cases
- Increase OVD – prop anterior open due to posterior inlays
- Decreased due to grinding (and attrition/erosion)
Fractured cusps
Restoration of root treated teeth
- Onlays provide cuspal coverage
Replace failed direct restorations
Minor bridge retainers (not recommended)
when wouldn’t provide inlay/onlay (4)
Active caries and periodontal diseases
Time
Tooth preparation and laboratory fabrication required
Cost
why restore teeth with crowns (5)
To protect weakened tooth structure
To improve or restore aesthetics
For use as a retainer for fixed bridgework
When indicated by the design of a RPD
- Rest seats
- Clasps - undercuts
- Guide planes – single POI
To restore tooth function
- e.g. restore in OVD
why not restore teeth with crowns (5)
Active caries and periodontal disease
More conservation options available
Lack of tooth tissue for preparation very destructive preparation – explore more conservative options first
Unable to provide post and core
Unfavourable occlusion – want to distribute occlusal contact points evenly around mouth
principles of crown preparation
to maximise success of providing crowns
1. Preservation of tooth structure
- Retention and resistance
- Structural durability
- Marginal integrity
- Preservation of the periodontium
- Aesthetic considerations
preservation of tooth structure for crown prep
Whenever possible preserve sound tooth structure to avoid:
- Weakening the tooth structure unnecessarily
- Damage to the pulp if tooth still alive (1 in 5 teeth become non vital when getting crowns – risk RCT)
Under preparation results in:
- Poor aesthetics (bulbous - crown made to right thickness; too thin looks bad)
- Over built crown with periodontal and occlusal consequences
Over preparation results in:
- Pulp and tooth strength being compromised
under prep for crown
- Poor aesthetics (bulbous - crown made to right thickness; too thin looks bad)
- Over built crown with periodontal and occlusal consequences
over prep for crown
- Pulp and tooth strength being compromised
what dictates degree of crown prep needed
Degree prep needed depend on material
- Metal on outside – thinner prep
- Porcelain involved – need to have thicker preparation
Porcelain only really needed on visible aspects (e.g. not palatal or lingual)
Must balance against criteria for retention and resistance and structural durability.
retention crowns
prevents removal of the restoration along the path of insertion or the long axis of the tooth preparation
resistances crowns
prevents dislodgement of the restoration by forces directed in an apical or oblique direction and prevents any movement of the restoration under occlusal forces
taper for crowns
ideal inclination of opposing walls is 6 degrees
length of walls for crowns
Longer walls interfere with tipping displacement
- More distance to slide before being able to slip off
2 ways of extra means of retention in crowns
grooves
slot
path of insertion for crowns
Imaginary line along which the restoration will be place onto or removed from the preparation.
Is set before the preparation is begun and all the features of the preparation must coincide with that line.
- Usually long axis of tooth
- Sometimes cusp from neighbouring tooth may impinge so need to alter path angle
Check POI from birds eye view
Retention is improved by limiting the number of paths of insertion.
how is retention improved for crowns
by limiting the number of paths of insertion.
structural durability of fixed prosthodontics
Restoration must contain a bulk of material that is adequate to withstand the forces of occlusion.
- Thinner metals
- Thicker ceramics
Achieved through:
- Occlusal reduction
- Functional cusp bevel
- Axial reduction
structural durability for fixed prosthodontics achieved through (3)
- Occlusal reduction
- Functional cusp bevel
- Axial reduction
occlusal reduction for fixed prosthodontics
2mm reduction for restoration
functional cusp bevel for fixed prosthodontics
Imp – cusp subjected under occlusal load
If not – sharp area with constant forces lead to fracture
Round off and remove sharp line angles
axial reduction for fixed prosthodontics
Tooth curves – convex shape
Reduce the tooth in at least two planes labially
- follow natural contour of tooth in labial, cervical and coronal aspects
marginal integrity for fixed prosthodontics
use chamfer or shoulder margins
preserve periodontium
margins of fixed prosthodontics restorations should be (3)
Smooth and fully exposed to a cleansing action.
Placed where the dentist can finish them and the patient can clean them.
Placed at gingival margin whenever possible.
- Placement of the margins subgingival may be required
do not encroach on biological width – height superior alveolar border to base sulcus
- Recession and hard to clean
be careful with aesthetics Vs function
Consider which material :
- Provides the best aesthetics? Will the restoration(s) be visible? Smile lines?
- Has the least destructive preparation?
- Is least destructive to opposing teeth?
Is best suited to bruxists?
- Pure Ceramic can cause tooth wear if bruxist
- Need MCC metal on palatal is more malleable – softer and stronger
- get hybrid MCC available
why replace teeth with bridge (6)
aesthetics
occlusal stability
- prevent tilting and overeruption of adj and opposing teeth
function
- mastication
- speech
- wind instruments
periodontal splinting
restoring OVD
pt preference
why not replace teeth with bridge (5)
Damage to tooth and pulp
Secondary caries
Effect on the periodontium
Cost
Failures
bridge design types (2 main categories and then 4 sub types)
Cantilever
– held on by one side
Fixed-fixed
– held on by restoration on either side
Adhesive/Resin-bonded/Resin retained “Conventional” (held on by crown) Hybrid Fixed-moveable Spring cantilever old, not used now
what does the pt need for informed consent of fixed prosthodontics
Invasiveness / reversibility
Likely longevity and success rates(evidence based)
Possible complications
Time involved
Costs
Alternative options
- Bleaching, composite (highlight if more conservative)
communication
- verbal
- written (best)
what do pt need to provide informed consent for
What treatment is to be performed
Why it is necessary
Consequences of not having treatment
What risks may be involved (material risks)
What alternatives are there (and their risks)
Relative costs
why is it very important to record pt informed consent given
pts may claim
- Did not know what treatment was being provided
- Did not know the cost implications
- Received no warnings about the risks involved
- Was not aware of alterative options
- Did not give consent
who makes diagnostic wax ups
chair-side by operator or sent to lab to do
good to try and attempt for tooth morphology
veneer survival rate
approx 10 years
crown survival rate
10-15 years
bridge survival rate
resin bonded 5-10 years
conventional 10 years
