Operative Dentistry Flashcards
F
The area of prosthodontics focused on permanently attached (fixed) dental prostheses. Such dental restorations are also referred to as indirect restorations
what are some types of indirect restorations?
Veneers
Inlays and Onlays
Crowns
Post and cores
Bridgework
what are diff types of special investigation?
- sensibility testing
- radiographs
- study models
- facebow
- diagnostic wax-up
what is purpose of a facebow?
to find relationship between maxilla and angles of the mandibular condyles
what are some additional info you could find out during tx planning?
Diet diary
Plaque and gingivitis indices
Full mouth periodontal chart
Clinical photographs
Microbiology, biopsy, haematology
what are stages of treatment planning?
- immediate
- initial
- re-evaluation
- reconstructive
- maintenance
what do you do during immediate stage for treatment?
- relief of acute symptoms
- consider endo and extractions
- consider immediate denture/bridge
what do you do during initial stage of treatment?
disease control
- extraction of hopeless teeth
- OHI and diet advice
- HPT
- Management of carious lesions and defective restorations with direct or provisional restorations
- endo
- denture design, wax up for fixed prosthodontics
what do you do during re-evaluation part of treatment?
- re-assessment of perio status, confirm denture/bridge design
what do you do during reconstructive part of treatment?
- perio surgery
- fixed and removable prosthodontics
why place veneers?
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
what do you do during maintenance part of treatment?
- supportive perio care and review of restorations
what is a diastema?
a gap between your teeth?
what is gurel minimal prep technique?
Wax up
Stent
Intra-oral mock up
Preparation into mock up (can use depth cut burs
when not to use veneers?
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
Labially positioned, severely rotated and overlapping teeth
Extensive TSL/insufficient bonding area
Heavy occlusal contacts
Severe discolouration
when is extensive prep needed so veneers can’t be used?
> 50% of surface area no longer in enamel
why restore teeth with inlays/onlays?
Tooth wear cases
* Increase OVD
Fractured cusps
Restoration of root treated teeth
Onlays provide cuspal coverage
Replace failed direct restorations
Minor bridge retainers (not recommended)
why not use inlays/onlays?
Active caries and periodontal diseases
Time
* Tooth preparation and laboratory fabrication required
Cost
Why restore teeth with crown?
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
* Guide planes
To restore tooth function
* e.g. restore in OVD
Why not restore with crowns?
Active caries and periodontal disease
More conservation options available
Lack of tooth tissue for preparation
Unable to provide post and core
Unfavourable occlusion
what are the principles of crown prep?
o 1) Preservation of tooth structure
o 2) Retention and resistance
o 3) Structural durability
o 4) Marginal integrity
o 5) Preservation of the periodontium
o 6) Aesthetic considerations
Whenever possible preserve sound tooth structure to avoid?
- Weakening the tooth structure unnecessarily
- Damage to the pulp
what does under preparation of crown prep result in?
- Poor aesthetics
- Over built crown with periodontal and occlusal consequences
- Restorations with insufficient thickness
what does over prep of crown prep result in?
Pulp and tooth strength being compromised
in terms of principle of crown prep what is meant by retention?
Prevents removal of the restoration along the path of insertion or the long axis of the tooth preparation
in terms of principle of crown prep what is meant by resistance?
Prevents dislodgement of the restoration by forces directed in an apical or oblique direction and prevents any movement of the restoration under occlusal forces
what is the ideal inclination of opposing walls with taper?
6-10 degrees
what do longer walls of a crown prep interfere with?
tipping displacement
in terms of principle of crown prep what is meant by path of insertion?
- 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
what are extra means of retention for crown preps?
- Grooves
- Slots
how is retention in crown preps improved?
limiting the number of paths of insertion.
what is structural durability of crown prep?
Restoration must contain a bulk of material that is adequate to withstand the forces of occlusion.
how is structural durability of crown prep achieved?
- Occlusal reduction
- Functional cusp bevel
- Axial reduction
what are finish line configurations for marginal integrity of crown preps?
- (a) Knife edge
- (b) Bevel
- (c) Chamfer
- (d) Shoulder
- (e) Bevelled shoulder
how should the margins of the restoration be when preserving the periodontium during crown preps?
- 1) Smooth and fully exposed to a cleansing action.
- 2) Placed where the dentist can finish them and the patient can clean them.
- 3) Placed supra-gingival or at gingival margin whenever possible.
o Placement of the margins subgingival may be required
what is considered when deciding aesthetic considerations of crown preps?
- Smile lines
- provides best aethetics so will the restoration(s) be visible?
- Has the least destructive preparation?
- Is least destructive to opposing teeth?
- Is best suited to bruxists?
when planning bridgework why replace teeth?
aesthetics
when planning bridgework what is occlusal stability?
Prevent tilting and overeruption of adjacent and opposing teeth
what not replace teeth for bridgework?
Damage to tooth and pulp
Secondary caries
Effect on the periodontium
Cost
Failures
what are the bridge designs?
o Cantilever
o Fixed-fixed
o Adhesive/Resin-bonded/Resin retained
o “Conventional”
o Hybrid
o Fixed-moveable
o Spring cantilever
what needs to be discussed for informed consent?
o What treatment is to be performed
o Why it is necessary
o Consequences of not having treatment
o What risks may be involved (material risks)
o What alternatives are there (and their risks)
o Relative costs
what do you use for sensibility testing?
- Ethyl chloride
- Electric pulp test (EPT)
what do you use for mounted study modelS?
Semi- or fully adjustable articulator
What are the conventional clinical stages for indirect restorations
o 1) Preparation
o 2) Temporisation
o 3) Impressions and occlusal records
o 4) Cementation
what do you use for chairside indirect restorations?
CAD-CAM
- milled from block of ceramic
what is an inlay?
o Intra-coronal restorations made in lab
Like a filling made outside the mouth
what are some types of inlays?
Gold
Composite
Porcelain
what are some uses of inlays?
Occlusal cavities
Occlusal/interproximal cavities
Replace failed direct restorations
what are some indications of inlays?
Premolars or molars
Occlusal restorations
Mesio-occlusal or disto-occlusal restoration
MOD
* If kept narrow
o If not – consider onlay
Low caries rate
advantages of inlays?
Superior materials and margins
Won’t deteriorate over time
disadvantages of inlays?
Time
Cost
what are tools needed for inlay prep?
- handpiece
- burs
- no.170L
- no. 169L
what are tools needed for inlay prep?
- handpiece
- burs
- no.170L
- no. 169L
- coarse-grit flame diamond
-flame - enamel hatches
- biangle chisel
- gingival margin trimmers
how to do an inlay prep for ceramic and gold?
ceramic
- 1.5 -2mm isthmus width
- 1.5mm depth
- 1mm min shoulder or chamfer margin
Gold
- 1mm isthmus width
- 1.5mm depth
- 0.5mm chamfer margin
occlusal key/dovetail
consider additional internal accessory retention features
- like grooves
alternative to inlays?
- Direct temporary materials
o Kalzinol (ZOE)
o Clip (a composite based material)
o GI
why do you not check occlusion of ceramic inlays?
weak when not cemented and may fracture
what are onlays?
o Extra-coronal restorations made in lab
Like inlays but with cuspal coverage
* Height of cusps need to be reduced during preparation
types of onlays?
Gold
Composite
Porcelain
indications for onlays?
Sufficient occlusal tooth substance loss
* Buccal and/or palatal/lingual cusps remaining
Remaining tooth substance weakened
* Caries
* pre-existing large restoration
o MODs with wide isthmuses
when are Cast metal inlays/onlays preferable to amalgam?
Higher strength needed
Significant tooth recontouring required
uses of onlays?
Tooth wear cases
* Increase OVD
Fractured cusps
Restoration of root treated teeth
Replace failed direct restorations
Minor bridge retainers (not recommended)
tools for onlay?
- handpiece
- burs
- no.170L
- no. 169L
- coarse-grit flame diamond
-flame - enamel hatches
- biangle chisel
- gingival margin trimmers
how to do an onlay prep for porcelain and gold?
porcelain
- non working cusp 1.5mm reduction
- working cusp - 2mm reduction
gold
- non working cusp 0.5mm reduction
- working cusp 1mm reduction
proximal box (if require0 1mm
margins
- porcelain - 1mm shoulder or chamfer
- gold - 0.5mm chamfer
how long do you give the lab for onlays and inlays to make?
2 weeks
alternatives to inlays and onlays?
o Large direct restorations
Amalgam
Composite
GI
o Crowns
¾ crown
* Gold
Full crown
* Gold shell crown (GSC)
* Metal-ceramic (MCC)
* Porcelain (PJC)
o Extraction
what are veneers also known as?
Porcelain laminate veneer (PLV)
Laminate veneer
what is a laminate veneer?
A laminate veneer is a thin layer of cast ceramic that is bonded to the labial or palatal surface of a tooth with resin.
types of veneer?
Ceramic
Composite
Gold
veneer indications?
- 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
what are some intrinsic indications for veeners?
- Non-vital teeth
- Ageing
- Trauma
- Medications (tetracycline)
- Fluorosis
- Hypoplasia or hypomineralisation
- Amelogenesis imperfecta
- Erosion and abrasion
what is amelogenesis imperfecta
a disorder that affects the structure and appearance of enamel on teeth
what is hypoplasia?
incomplete development of organ
hypominerlisation definition?
a softening or discolouration of enamel on teeth
what are extrinsic indications for veneers?
Staining not amenable to bleaching
what are some contraindications to veneers?
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
Labially positioned, severely rotated and overlapping teeth
Extensive TSL/insufficient bonding area
Heavy occlusal contacts
Severe discolouration
how to do a veneer prep?
use
- putty index
- depth cuts
cervical reduction
- 0.3mm
- slight chamfer margin
- within enamel
- supraginigval or slightly subginigval
midfacial reduction
- 0.5mm
- within enamel
incisal reduction
- 1-1.5mm
what are veneer prep types?
- feathered incisal edge
- incisal bevel
- intra-enamle (window)
- overlapped incisal edge
what is minimal prep technique for veneers called?
gurel technique
what is alternative to veneers?
No treatment
Micro-abrasion
Penetrative resin restorations – e.g., ICON
Direct composite restorations
Crowns
what are the clinical stages of indirect restorations?
- preparation
- temporisation
3.impressions and registration - cementation
- success of each stage dependant on preceding stage
in terms of provisional restoration characteristics how does tooth prep affect it?
Compromises aesthetics in smile line
Degrades tooth function
in terms of provisional restoration characteristics how does tooth prep affect degrade the tooth function?
- Occlusion reduction
- Destabilises occlusion
in terms of provisional restoration characteristics how does reduction to occlusal and interproximal affect it?
Render a vital tooth sensitive
* Exposed dentine
Compromise coronal seal of RCT’d teeth (in some cases)
provisionals should restore these characteristics
what should provisional restorations have?
Have good marginal fit
Be well contoured
* E.g. no overhangs
Cleansable and maintainable by patient
* “Optimum home care”
how does a poorly fitting and contoured provisional lead to?
Patient unable to clean
* Caries
* Gingival inflammation
o Poor moisture control
o Gingival overgrowth
what should provisional restorations must do?
Establish and/or maintain dental aesthetics, mimicking either
* Original tooth
* Definitive restoration
Prevent sensitivity
Allow “optimum home care”
* Prevent plaque build-up and caries
* Maintain gingival health and contour
Prevent microleakage/bacterial leakage
* Preserve tooth vitality
how do you check provisional restoration is occlusally stable?
No OVD changes (unless desired)
Prevent drifting or tilting of prepared teeth
what are additional uses of provisional restorations?
Isolation for RCT
Matrix for core build-up
what are Desirable characteristics of provisional materials?
- non irritant
- pulp
- periodontal tissues
- low temp rise during setting
- dimensionally stable
- adequate working time
- adequate setting time
- adequate strength and wear resistance
- good aesthetics
what are types of provisional restorations?
o Custom formed
“Bespoke” to individual situations
Preferable
Can be technically demanding
o Preformed
Standard shapes and sizes
Adjust to fit chairside
what material is a custom resin provisional crown? and give 2 examples?
Chemically cured bis-acrylic composite resin
* Examples:
o Protemp Plus (3M ESPE)
o Integrity Temp-Grip (Dentsply)
in what way is a custom resin provisonal crowns customisable?
o Fits tooth prep internally
o Reproduces contact points and occlusion externally
what must you do before you start a custom resin provisional crown?
o Make before impressions for definitive restoration are taken
Helps check that tooth prep is satisfactory
* ? Undercuts
* Sufficient reduction
how do you check that there is sufficient reduction?
svensen gauge
what are some material you can use to take impressions for custom resin proviosnal crown? and features of all?
Addition cured silicone putty (e.g. President)
* Can be disinfected and kept by patient or clinician; Can be reused; Resistant to tearing
Alginate
* Cheaper;
* Cannot be reused or kept
Softened modelling wax
* Easy to adjust and smooth; Cheap; Unsuitable for deep undercuts; Distorts; Cannot be reused
what kind of an impression do you take for custom resin provisional crowns?
sectional impression - not whole arch
why do you not take full arch impression for custom resin provisional crown?
difficult to re-seat
describe in detail the method for custom resin provisional crown?
) Sectional impression
2) Prepare tooth for chosen restoration
3) Syringe bis-acrylic composite resin material onto bracket table or mixing pad
* I) Ensure its mixed
* II) Monitor setting
4) Syringe material into sectional impression of tooth that has been prepared
5) Relocate impression in the mouth
* I) Ensure fully seated
* II) “click” over bulbosity of remaining teeth
) Remove before complete polymerisation
* “Rubbery”
* Fully polymerised material difficult to remove from undercuts
7) Remove completely
* May:
o Stay on tooth
Gently ease off with instrument beneath the contact points
Otherwise: sets in undercuts
o Be removed in the impression
Leave to completely set
8) Remove flash and ledges
* High speed and/or polishing discs
) Confirm tooth preparation
* Svensen gauge
Check marginal fit and occlusion in situ
* Adjust if required (ideally outside the mouth)
Check aesthetics
Cement provisional restoration
where is fully polymerised material difficult to remove from?
undercuts
how to confirm tooth prep?
svensen gauge
what is examples of temporary luting cement?
TempBond NE (Kerr Dental) - Non-eugenol temporary cement material
descrie inlay provisional method?
- sectional impression using putty?
- inlay prep
- syringe material into pre-op impression
- re-seat pre-op impression
- remove pre-op impression and provisional restoration
- remove flash and ledges
- check tooth prep and provisional thickness
- cement provisional restoration
- remove excess cement and polish
how to re-establish tooth shape for loss of original tooth form in wear cases?
o Guidance (anterior/incisal)
Produce on crowns
* Diagnostic wax up
* Articulated study models
* FaceBow registration required
once guidance and aesthetics satisfactory when establish occlusion and aesthetics what happens?
Lab
* Duplicate waxed-up cast
* Construct vacuum-formed mould/stent/template
Next patient visit
* Prepare teeth
* o Use vacuum formed mould to produce custom-formed provisional restorations to new occlusion and appearance
when patient wear provisionals for trial period when establish occlusion and aesthetics what do you reassess?
Aesthetics
Occlusion
If satisfactory definitive restorations
If not, make alterations and reassess further
when you transfer guidance created on provisionals to definitive restorations what happens?
- Customised formed incisal guidance table created:
o Impressions of Provisionals in-situ and opposing teeth
o Mount casts on semi-adjustable articulator
Place unset acrylic on incisal table
Reproduce lateral and protrusive movements
describe impressions of tooth prep for definitive restorations?
Master cast mounted on articulator
Technician constructs definitive restorations
* Constantly checks again excursive movements
o Guided by custom-formed incisal table
Simultaneous contact between restorations/opposing teeth and incisal pin/guidance table
describe diagnostic wax up for establishing occlusion and aesthetics?
Satisfy patient’s aesthetic demands
High aesthetic demand cases
* Alter provisional restorations
o Minor changes – chairside
Burs
Addition of provisional material or composite
Extensive changes
* Replace provisional restorations
Once satisfactory
* Make impression for technician
what are the diff variations of preformed provisional crowns?
Tooth coloured
* Polycarbonate (Directa)
* Clear-plastic crown forms
o Filled with composite
Metal
* Aluminium
* Stainless steel
Different shapes/morphology and sizes
what are problems with preformed provisional crowns?
Unlikely to fit accurately
* Cervically
* Occlusally
* Interdentally
Large bank of crowns needed
* Accommodate variation between patients
* Costly
what situations are preformed provisional crowns useful for?
- Useful for situations where no impression taken prior to tooth preparation or damage
o E.g. trauma cases
describe method of doing a preformed metal crown?
) Select shell slightly larger than preparation
2) Trim back until
* Correct preparation dimension
* Seats fully over tooth preparation
* Not bedding into gingivae
o Pink stone in straight handpiece
3) Fill shell
* Trim or Protemp
4) Seat over tooth
5) Allow polymerisation
6) Remove
7) Check fit
8) Trim/Tidy if necessary
9) Cement
* Temporary luting cement (e.g. Tempbond)
10) Cut off tag NOTE: If overbuilt – blanching of gingivae occurs
what happens if preformed metal crown is overbuilt?
blanching of gingivae occurs
what is method for doing a clear plastic provisional restoration?
1) Select and trim until fit
Pierce hole at cusp tip/canine tip/incisal angle
* Air escapes
* No bubbles
3) Fill with bis-acrylic composite resin
4) Seat over tooth
5) Allow setting
6) Remove from tooth
7) Remove plastic crown form
8) Check margins and occlusion
* Adjust if necessary
9) Cement with temporary cement
what are metal provisional crowns used for?
posterior teeth
what types of materials are used for metal provisional crown?
- Aluminium
- Stainless steel
what are some metal provisional restoration materials provided with?
crimping device
what is purpose of a crimping device?
help mould margins
what do you use to remove an old crown?
WAMkey
Safe Relax/Anthrogyr
Sliding hammer
how to replace an old crown?
Can use/modify original crown for temporary
* May need partially sectioned/relined
o Preserve original crown as much as possible
what is method of using a preformed malleable comp crown?
Moulded over tooth to desired shape
Partially light cured
* 2-3 secs
* Otherwise – difficult to remove
Remove then completely cure outside of mouth
Check fit
Adjust if necessary
Cement
what kind of provisional restorations are used for veneers?
spot bonded composite
what are features to lab made indirect provisional restorations?
- Low shrinkage intra-orally
- More accurate
- High strength
- Time and cost consuming
- Used long-term
what can you do for provisional replacement of missing teeth?
o Conventional bridgework temporisation
o Resin-bonded bridges (minimal preparation) and implants
what do you do for a conventional bridgework temporisation?
diagnostic wax up of replacement tooth
what advice do you give when giving a provisional restoration?
must maintain good OH
Brushing 2-3x daily
Interdentally cleaning 1-2x daily
what must you be cautious with using with a provisional restoration?
floss
- may pull out provisional restoration
what happens if patient doesn’t have good OH with a provisional in?
- Gingival inflammation
o Increased:
GCF
Bleeding
Poor moisture control for definitive impressions
Inadequate cement lute placement