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
what are the causes of tooth dicolouration?
o Extrinsic
o Chromogenic Bacteria
o Chlorhexidine
o Iron supplements
o Intrinsic
what are extrinsic tooth discolouration examples?
Smoking
Tannins
* Tea
* Coffee
* Red Wine
* Guinness
what are intrinsic tooth discolouration examples?
Fluorosis
Tetracycline
Non-vitality (blood products)
Physiological (age changes)
Dental Materials
* Amalgam
* Root filling materials
Porphyria (red primary teeth)
Cystic Fibrosis (grey teeth)
Thalassemia, Sickle Cell anaemia (blue, green or brown teeth)
Hyperbilirubinaemia (green teeth)
what are signs of tooth discolouration for non vital teeth?
blood products
how does porphyria relate to tooth discolouration?
red primary teeth
how does cystic fibrosis relate to tooth discolouration?
grey teeth
how does thalassemia and sickle cell anaemia relate to tooth discolouration?
blue, green or brown teeth
how does hyperbilirubinaemia relate to tooth discolouration?
green teeth
what is first method of tooth whitneing for extrinisc staining?
HPT
what are the 2 types of tooth bleaching?
External Vital Bleaching
Internal Non-vital bleaching
explain vital external bleaching?
o Discolouration is caused by the formation of chemically stable, chromogenic products within the tooth substance.
o These are long chain organic molecules.
o Bleaching oxidises these compounds.
o Oxidation leads to smaller molecules which are often not pigmented
o Oxidation can cause ionic exchange in metallic molecules leading to lighter colour
what is the active agent in vital external bleaching?
hydrogen peroxide (H2O2)
what does H2O2 do?
Forms an acidic solution in water
Breaks down to form water and oxygen
Free radical per hydroxyl (HO2)is formed. This is the active oxidising agent.
Fast reacting oxidising agent
Used as bleaching agent in industry
Used to bleach hair
Used as a disinfectant
Seldom an ingredient in modern tooth bleaching products.
what is the active oxidising agent in vital external bleaching?
free radical per hydroxyl (HO2)
what are some constituents of bleaching gel?
Carbamide peroxide
Carbopol
Urea
Surfactant
Pigment dispersers
Preservative
Flavour
Potassium Nitrate
Calcium Phosphate
Fluoride
what is active ingredient in vital external bleaching?
carbamide peroxide
what does carbamide peroxide do?
breaks down to produce hydrogen peroxide and urea?
what does urea do?
increase pH
stabilises hydrogen peroxide
what is the thickening agent in vital external bleaching?
carbopol
what is purpose of carbopol?
Slows the release of oxygen
Increases the viscosity of the gel stays where you put it
Stays on teeth
Stays in tray
Slows diffusion into enamel
what does surfactant do in external tooth bleaching?
Allows the gel to wet the tooth surface
what are Potassium Nitrate, Calcium Phosphate in external tooth bleaching?
Tooth desensitising agents
what are Potassium Nitrate, Calcium Phosphate in external tooth bleaching?
Tooth desensitising agents
what does fluoride do in external tooth bleaching?
Prevents erosion
Desensitising effect
what factors affect external vital bleaching?
o Time
More time more effect
o Cleanliness of the tooth surface
Cleaner better
o Concentration of solution
Higher concentration more and quicker effect
o Temperature
Higher quicker effect
what must you always do before you start teeth bleaching?
o Before you start always check patient is dentally fit. Any leakage around carious cavity margins will lead to pulpal damage
o Take an initial shade, agree it with the patient and record it in their notes. Better still take a photo with a shade guide included in the picture
what warnings do you give patient for tooth bleaching?
Sensitivity
Relapse
Restoration colour
Allergy
Might not work
Compliance with regime
what are 2 types of vital external bleaching?
chair-side/in office
home
what are advantages of in office vital external bleaching?
o Controlled by dentist
o Can use heat/light
o Quick results for patient
what are disadvantages of in office vital external bleaching?
o Time for dentist
o Can be uncomfortable
o Results tend to wear off quicker
o Expensive
what is technique for in office vital external bleaching?
o Thorough cleaning of teeth
o Ideally rubber dam
o At least gingival mask
o Apply bleaching gel to tooth
o Apply heat/light
o Wash/dry/repeat
o Takes 30mins to an Hour
what is essential for in office vital external bleaching?
protection of gingiva
what strength carbamide peroxide gel is used for home vital external bleaching?
10%-15% Carbamide Peroxide Gel
what is technique for home vital external bleaching?
o A custom made set of mouth guards are required
o Alginate impressions of teeth
o 0.5mm thick soft, acrylic, vacuum formed soft splint made
o Should stop short of gingival margin (1mm)
o Buccal spacer to allow for placement of gel
how does heat/light/laser give a good initial result?
Mainly due to dehydration
Wears off quickly
what is technique for home vital external belaching both in surgery and at home? when do you see results?
o In Surgery
Full mouth cleaning/polishing of teeth in surgery
Fit trays and check extension/comfort
Instruction in use
o At Home
Brush and floss teeth
Load tray
* 1mm2 dot buccally on each tooth
Fit tray in mouth
* Requires to be in place for at least 2 hrs
* Preferably overnight
o Clear written instructions given
o Review at 1 week
o Results are variable
Most patient see a result within 2 – 3 days
Normally reached maximum by 3 – 4 weeks
If no change in 2 weeks it is not going to work
how much is given for each tooth in tray for home vital external bleaching?
1mm^2 buccally
how long is tray to be in mouth for?
2 hrs preferably overnight
when do you review home vital external bleaching?
1 week
when should patient see a result for home vital external bleaching?
2-3 days
when is maximum effect achieved for home vital external bleaching?
3-4 weeks
when do you know if home vital external bleachign isn’t going to work?
if no change in 2 weeks
when to bleach?
o Age related darkening/discolouration
Teeth with yellow/orange discolouration respond better than those with bluish/grey discolouration
o Mild fluorosis
o Post smoking cessation
Don’t bleach smokers it is a waste of time
o Tetracyclin staining?
Prolonged treatment
Better with yellow and brown than grey
Can take months
what are some bleaching problems?
Sensitivity
Wears off
Cytotoxicity/Mutagenicity
Gingival irritation
Tooth damage
Problems with bonding to tooth
when does sensitivity resolve after bleaching?
2-3 days post
what are predictors of sensitivity for bleaching?
o Pre-existing sensitivity
o High concentration of Bleaching agent
o Frequency of change
o Bleaching method
o Gingival recession
how does wear off happen in regards to bleaching? when retreat?
- Oxidised chromogens gradually reduce with time
- Retreatment 1-3 years, varies
what can cause problems in relation to Cytotoxicity/Mutagenicity for bleaching?
high conc hydrogen peroxide
what is gingival irritation in relation to for bleaching?
related to conc
must check tray extension correct
what happens with problems related to bonding to tooth for bleaching?
- Residual oxygen from the peroxide remains within the enamel structure initially
- Gradually dissipates over a short time
o Delay restorative procedures for at least 24hrs post bleaching
o Better to delay for a week
what must never be used for tooth bleaching?
chlorine dioxide
o Chlorine dioxide has a pH of around 3 and will soften the tooth surface.
o As a result of chlorine dioxide use, teeth are more prone to re-staining, develop a rough surface and become extremely sensitive.
what are causes of internal non vital bleaching?
Dead pulp bleeding into dentine
Blood products diffuse and darken
Grey discolouration
what are indications of internal non vital bleaching?
Non-vital tooth
Adequate RCT
No apical path
what are contraindications of internal non vital bleaching?
Heavily restored tooth
* Better with crown or veneer
Staining due to amalgam
what are limitations of internal non vital bleaching?
Doesn’t always work but generally worth a go.
what are advantages of internal non vital bleaching?
Easy
Conservative
Patient satisfaction
what are risks of internal non vital bleaching?
External Cervical resorption
what is external cervical resorption due to?
- Due to diffusion of H2O2 through dentine into periodontal tissues
- High conc H2O2 and heat
- Trauma important
what is the technique to internal non vital bleaching?
o Record shade
o Prophylaxis
o Rubber dam
o Remove filling from access cavity
o Remove GP from pulp chamber and 1mm below amelo-cemental junction
o Place 1mm RMGIC over GP to seal canal
Seals dentine and prevents root resorption
o Remove any very dark dentine
o Etch the internal surface of the tooth with 37% phosphoric acid
o Place 10% carbamide peroxide gel in cavity
o Cotton wool over this
o Seal with GIC
o Repeat procedure at weekly intervals
o Repeat until
Required shade achieved
No change
o Once final shade obtained restore the palatal cavity
o Place white GP or similar in pulp chamber
o Restore with light shade of composite
o Will gradually darken again
o Retreatment every 4 – 5 years? Variable
how many visits until internal non vital bleaching is not going to work?
Normally takes 3 – 4 visits. If no change after 4 visits it is not going to work and consider crown /veneer/ composite build up.
what is combination bleaching?
o Inside-outside bleaching
o Remove GP, as before, cover with RMGIC
o Make bleaching tray
Palatal not buccal reservoir
o Bleach placed in access cavity and in tray
o Replaced frequently over about a week
o Tricky for patient, must wear tray whole time
what is micro-abrasion?
- removes discolouration limited to outer layers of enamel
- combination of erosion (acid) and abrasion (pumice)
what are indications of micro-abrasion?
- fluorosis
- post ortho demineralisation
- demineralisation with staining
- prior to veneering if dark staining is present
what is technique of micro abrasion?
o Clean teeth thoroughly
o Rubber dam (seal is very important)
o Mix 18% HCl and pumice
o Apply to teeth
o Gently rub with prophy cup 5 seconds/tooth
o Wash
o Repeat up to 10X
o Remove rubber dam
o Polish teeth with fluoride prophy paste
o Apply fluoride gel or varnish
Fluoride to help reharden the surface and decrease sensitivity
o Review after one month
o Can be repeated
Too much can lead to yellowing of the tooth as the dentine begins to show through
Too much will lead to permanent sensitivity
why apply fluoride gel or varnish for micro abrasion?
Fluoride to help reharden the surface and decrease sensitivity
what happens if too much micro abrasion is done?
Too much can lead to yellowing of the tooth as the dentine begins to show through
Too much will lead to permanent sensitivity
advantages of micro abrasion?
Quick
Easy
No long term problems
* Pulpal damage
* caries
disadvantages of micro abrasion?
Acid
Sensitivity
Only works for superficial staining
Works much better for brown staining than white marks.
what does resin infiltration do?
o Don’t remove the surface layer
o Infiltrate the white area with resin
o Changes the refractive index of the white area
o Masks it and makes it look like the surrounding enamel
o Marketed initially as a method of treating early caries by resin infiltration
o Used for treatment of white spot lesions
o Hyrdophilic resin impregnation of the porous enamel surface in white area
how is resin infiltration marketed?
Marketed initially as a method of treating early caries by resin infiltration
what is resin infiltration used for?
Used for treatment of white spot lesions
what regulations does teeth whitening fall into?
cosmetic products (safety amendment) regulations 2012
what are medical contraindications to teeth whitening?
- Glucose-6-Phosphate dehydrogenase deficiency
- Acatalasemia
o Neither group can metabolise hydrogen peroxide.
what is it illegal for teeth whitening products to contain?
more than 6 percent H2O2
when is it illegal to use the recommended limit of hydrogen peroxide in teeth whitening?
Products containing or releasing between 0.1% and 6% hydrogen peroxide cannot be used on any person under 18 years of age except where such use is intended wholly for the purpose of preventing disease
what are outcome predictors of dental trauma?
o Severity of injury sustained
Risk calculator IADT dental trauma guide
Prognoses for teeth with trauma dental injuries
Copenhagen trauma database
Dental trauma guide website
o Stage of root development
o Timing of treatment
what are risk of complcations?
o Crown fractures
o Concussion
o Subluxation
o Extrusion
o Lateral luxation
o Dento-alveolar fracture
o Intrusion
what are types of crown fractures and complication? and risk of 10 years %
- enamel-dentine fracture with pulp necrosis complication - 5 percent
- enamel-dentine fracture with pulp canal obliteration complication - 1 percent
- enamel-dentine-pulp fracture with pulp canal obliteration complication - 20 percent
what are complication following concussion injuries?and risk 1 year, 3 years, 10 years (%)
pulp necrosis - 3.5 (1,3,10)
pulp canal obliteration - 4 (1), 7 (3), 10 (10)
external root resorption - 5 (1), 8(3), 8 (10)
complications following subluxation and estimated risk % for years 1,3,10
pulp necrosis - 12.5 (1,3,10)
external root resorption 2.7 (1,3,10)
bone loss - 1(1,3,10)
complications following extrusion and estimated risk % for years 1,3,10
pulp necrosis - 56.5 (1,3), >56.5 (10)
pulp canal obliteration - 22 (1,3), >22 (10)
external root resorption - 27 (1,3,10)
bone loss - 17 (1,3,10)
complications following lateral luxation and estimated risk % for years 1,3,10
pulp necrosis - 65 (1), 73 (3), 75 (10)
pulp canal obliteration - 13 (1,3), 18 (10)
external root resorption - 31 (1), 34 (3,10)
bone loss - 6 (1,3,10)
ankylosis - 1(1,3,10)
internal root resorption - 1 (1) , 3 (3, 10)
complications following dento-alveolar fracture and estimated risk % for years 1,3,10
tooth loss - 2 (1), 8(3), 10(10)
pulp necrosis - 38 (1), 42 (3), 45 (10)
pulp canal obliteration - 7 (1), 12 (3), 13 (10)
external root resorption - 5 (1,3,10)
bone loss - 8 (1,3,10)
ankylosis - 1(1), 2 (3, 10)
internal root resorption - 2 (1) , 3 (3), 4(10)
complications following intrusion and estimated risk % for years 1,3,10
tooth loss - 0 (1), 5(3), 29(10)
pulp necrosis - 100 (1,3,10)
external root resorption - 5 (1,3,10)
bone loss - 43(1), 57 (3), 63(10)
ankylosis - 10(1), 26(3), 38(10)
internal root resorption - 5(1,3,10)
open vs closed apex?
open
- maintain pulpal vitality
- preservation of blood supply
closed
- maintain pulpal vitality
- preservation of blood supply
- prevent ingress of or eliminate bacteria and toxins
timing of treatment of trauma?
Pulp necrosis and root resorption common with very delayed or no trauma treatment
what are the different timings of treatment?
Acute: <3 hours
Subacute: 3-24 hours
Delayed: >24 hours
what is recommended treatment timing protocol?
avulsion - immediate re-implantation or acute (or subacute)
alveolar fracture - acute
extrusion or lateral luxation - acute or subacute
root fracture - acute or subacute
concussion or subluxation - subacute
crown or crown root fractures - subacute or delayed
what are the potential long term implications of trauma?
o Discolouration
o Loss of vitality
o Inflammatory root resorption
o Unfavourable tooth positions
o Defects in hard and soft tissues
what is external discolouration?
accumulation of staining
what is yellow discolouration of trauma indicative of?
Indicative of canal obliteration
what does tertiary dentine reduce?
light transmission
what should you consider for yellow discolouration of trauma?
local external bleaching
what is the causes of pink/red discolouration due to trauma?
rupture of blood vessels duing severe trauma may cause heamorrhe in pulp chamber
blood components flow into dentinal tubules, causing discolouration of the surrounding dentin
initially pink
cervical root resorption may also present as pink discolouration at the cervical margin of the crown
Potential later complication of trauma
Often initial presentation of cervical root resorption in absences of radiographs
how is reversal of pink discolouration due to trauma?
- No necrosis discolouration may reverse over time s the pulp revascularizes (2-3 months)
- If pulpal necrosis discolouration will worse over time
when should pulp revascularise?
2-3 months
what is brown-grey-black discolouration of trauma?
In non-infected traumatised teeth accumulation of haemoglobin molecule or other haematin molecules causes discolouration
In non vital teeth hydrogen sulfates produced by bacteria convert iron to dark coloured iron sulfates
Important to understand if trauma has caused loss of vitality or not
in regards to loss of vitality for pulp necrosis and apical periodontitis when does it occur?
Occurs following trauma if revascularisation fails
describe loss of vitality in regards to pulp necrosis and apical periodontitis?
- Pulp tissue will undergo sterile necrosis
- Subsequent bacterial infection may then occur
- After 3-4 weeks radiographic indications of pulp necrosis
- Development of apical periodontitis
- Apical radiolucency on radiograph
what are diagnostic indicators of pulp necrosis
- Periapical radiolucency
- Discolouration of tooth crown (usually grey/brown)
- Infection related to external root resorption
- No response to pulp sensitivity test
- Tenderness to percussion and palpation in the vestivule develops after an asymptomatic period
- Presence of a fistula (sinus tract)
what colour is an indicator of pulp necrosis?
grey/brown
what is infection related to for pulp necrosis?
external root resorption
what is treatment of pulpal necrosis?
- Primary endo
- Internal bleaching
- Extraction and prosthetic replacement
what are types of displacement injuries?
- Luxation
- Intrusion
- Extrusion
- Avulsion
what do you do during tooth movement following displacement injury?
Repositioning and splinting within 24 hours to minimise risk of complications
how to manage unfavourable tooth positions?
- Simple restorative treatment
- Ortho repositioning
- Treatment
- Full assessment required
when is ortho repositioning used for displament injuries?
o Late presentation of injuries
o Injuries incorrectly repositioned
what are increased risks associated with ortho?
Root resorption
Loss of vitality
when to treat infra-occluded teeth?
before >4mm infra-occlusion present
what factors does tx of infra-occluded teeth depend on?
- prognosis of teeth
- degree of infra-occlusion
- wishes of pt
- lip line
what factors does tx of infra-occluded teeth depend on?
- prognosis of teeth
- degree of infra-occlusion
- wishes of pt
- lip line
what is defects in hard and soft tissues as long term implication of trauma?
Loss of tissue during acute injury
* Gingival lacerations/abrasion
* Alveolar fractures
when will deficiencies develop in regards to defects in hard and soft tissues?
- Early extraction
- Ankylosis
o Lack of development of alveolar process and gingival margin discrepancy
o Bone loss during extraction - Endo failures
how do you manage hard and soft tissue defects in adults?
o Bone deficiencies
Bone grafting procedures
Ortho extrusion therapy (as long as no ankylosis/replacement resorption)
o Soft tissue deficiencies
Mucogingival surgery
CT grafting to increase volume of keratinised mucosa
o Implant treatment complex
o Aesthetically challenging
how do you manage hard and soft tissue defects in children?
o Extraction of teeth
Bone loss
coronectomy
* aims for continued bone deposition
Osteogenic distraction
Camouflage
when to refer complex trauma?
Injury <= 5 days old appointment same day
Injury >= 5 days old but not long term complication next available appointment
what may require specialist tx?
Inflammatory root resorption
* External cervical root resorption
* Internal inflammatory root resorption
* External inflammatory resorption
Altered tooth position
* May require multi-disciplinary care
Root fractures exhibiting developing pathology
Loss of > 1 tooth as a result of trauma
* High priority category for implant treatment in NHS
how do you mark the anterior ref point for facebow?
- Mark the anterior reference point on the patient’s right side using the Reference Plane Locator and Marker.
- This is 43mm apical to the incisal edge of the anterior teeth (12 ideally)
- It is the approximate position of the infraorbital foramen
how do you do a bite registration using the bite fork?
Bite registration paste applied to bite fork. Bite fork arm to the right and locating notch facing up
Firmly seat to record cusp tips of maxillary teeth. You can use rigid wax or bite registration paste. Do not engage undercuts.
Check that it is parallel with the patients’ coronal and horizontal planes
what are the two choices of interocclusal registration you can use to mount the lower cast?
Intercuspal Position (ICP)
- Conformative Approach
Retruded Contact Position (RCP)
- Reorganised Approach
how is ICP registration done?
- wax
- paste
- no material
- record block
before embarking on treatment in terms of occlusion you must decide what?
Before embarking on treatment you must decide whether to place restorations in the existing occlusal scheme (conformative approach) or to change it deliberately (the reorganized approach). If the entire occlusal scheme is to be reorganized to create a new and stable position, the final restorations are made in the new ICP that coincides with RCP and may involve a change in the vertical dimension
what do you need to mount lower cast?
RCP registration WITH or WITHOUT OVD increase
- reorganised approach
- not simple
ICP registration WITH OVD increase
- reorganised approach
- not simple
ICP registration WITHOUT OVD increase
- conformative approach
- simple
how is the confrormative approach defined?
the provision of restorations ‘in harmony with the existing jaw relationships
what does the conformative approach mean?
This means that the occlusion of the new restoration is provided in such a way that the occlusal contacts of the other teeth remain unaltered
what is it called when you mark contacts before change them?
tripodised contacts
When do we not use the conformative approach?
An increase in vertical height is needed to make space for restorations
Tooth/teeth significantly out of position (ie overerupted, tilted or rotated)
A significant change in appearance is wanted
There is a history of occlusally related failure or fracture of existing restorations
what is reorganised appracoh?
Plan to provide new restorations to a different occlusion
The occlusion is definedbeforethe work is started
Provide restorations, which change the occlusion but are well tolerated by the patient
why do you do reorganised approach?
ICP is non-existent or no use
You need space to place restorations
RAP is a reproducible position of the mandible independent of the teeth
what does the line between RCP and R mean on the occlusion picture?
retruded arc of closure
what are the techniques for interocclusal record in RCP?
Bimanual Manipulation
Chin Point guidance
Chin point guidance with anterior jig
what are the techniques for interocclusal record in RCP?
Bimanual Manipulation
Chin Point guidance
Chin point guidance with anterior jig
what does it mean to take interocclusal record in RCP?
The patient is guided into a terminal hinge closure to detect where initial tooth contact occurs (RCP).
how is the RCP interocclusal record taken?
The RCP record is taken at a slightly increased OVD just prior to this initial tooth contact (the mandible is rotating about its terminal hinge axis)
how is RCP registration done?
- wax
- paste
- record block
what is a centric relation premature contact?
Initial tooth contact (RCP) can occur at any point on the retruded arc of closure
what is rcp to icp slide on picture occlusion diagram?
If initial contact is on the posterior teeth then there is likely to be a slide from RCP to ICP as the patient tries to achieve maximum intercuspation of the teeth
what is RCP usually to ICP in comparison?
RCP is usually infero-posterior to ICP by 0.5–2 mm
what does R mean on occlusion diagram picture?
retruded axis Also known as terminal hinge axis
what does T mean on occlusion diagram picture?
maximum opening
when rostoring anterior teeth we can do what 2 things?
Copy the existing guidance
- Simple
- Conformative
- Most often
Change guidance
- Not simple
- Reorganised
- Less often
what does a mutually protected occlusion have?
canine guidance
where is the TMJ found?
The TMJ is the joint between the condylar head of the mandible and the mandibular fossa of the temporal bone
what type of join is TMJ?
TMJ is a synovial, condylar and hinge-type joint. The joint involves fibrocartilaginous surfaces and an articular discs which divides the joint into two cavities.
muscles involved in madnibular movement?
Muscles of Mastication
Involved in depression, elevation and lateral movements of the mandible
Suprahyoid Muscles
Elevate the hyoid bone or depress the mandible
- Mylohyoid elevates the hyoid bone and the floor of the mouth
- Stylohyoid initiates swallowing by puling the hyoid bone posterior superior
- Digastric and Geniohyoid depresses the mandible and elevates the hyoid
what is actions of temporalis?
Elevates the mandible closing the mouth and also retracts the mandible pulling the jaw posteriorly
action of masseter?
Elevates the mandible closing the mouth
actions of lateral pterygoid?
protract the mandible pushing the jaw forwards. Unilateral action produces a side to side or lateral movement of the jaw
actions of medial pterygoid?
Elevates the mandible, closing the mouth, some lateral movement
what are 2 major types of mandibular movement?
rotation and translocation
what is hinge movement?
roation
- Small amount of mouth opening (up to 20mm)
Condyle and disc remains within the articular fossa
No downwards or forwards movement
Also known as “hinge movement”
what is terminal hinge axis?
hinge movement
- Rotation of the condylar heads around an imaginary horizontal line through the rotational centers of the condyles
The imaginary line is termed the terminal hinge axis
what is a facebow?
a facebow is a caliper like instrument that records the relationship of the the maxilla to the terminal hinge axis of rotation of the mandible. It allows a maxillary cast to be placed in an equivalent relation ship on the articulator
what are border movements?
sagittal plane
horizontal plane
frontal plane
what is posselts envelope?
Extremes of mandibular movement
Border movements of the mandible in the Sagittal Plane
for posselts envelope diagram what do all the letters stand for?
ICP = Intercuspal position
E = Edge to Edge
Pr = Protrusion
T = Maximum opening
R = Retruded Axis Position
RCP = Retruded contact position
what is intercuspal position?
Tooth position regardless of the condylar position
The comfortable bite
Best fit of the teeth
Maximum interdigitation of the teeth
Can be called centric occlusion (CO)
what is edge to edge?
Tooth position
Teeth slide forward from ICP guiding on palatal surfaces of anterior teeth
Incisal edges of upper and lower incisors touch
what is protrusion?
Condyle moves forwards and downwards on articular eminence
Only incisors +/- canines touch
No posterior tooth contacts
Eventually no tooth contacts
what is maximum opening (T)?
No tooth contacts
Mouth wide open
Full translation of the condyle over the articular eminence
what is retruded axis position?
No tooth contacts
Most superior anterior position of the condylar head in the fossa
Terminal hinge axis
what is retruded contact position?
First tooth contact when the mandible is in retruded axis position
ICP is approximately 1mm anterior to RCP in 90% of the population
what is ICP-RCP slide?
ICP is approximately 1mm anterior to RCP in 90% of the population
RCP and ICP not coincident so the mandible slides forward to achieve ICP
what is working and non working side?
Mandible moving to the right = right side is the working side
Mandible moving away from the left = left side is the non-working side
What is bennet movement?
Lateral translation of the mandible is also known as the Bennet movement
what is bennet angle?
The path of the nonworking condyle in the horizontal plane during lateral excursion
When to mark tooth contacts?
Before
Preparing a tooth
Removing a restoration
After
Placement of a crown
Placement of a restoration
what are functional cusps?
Cusps that occlude with the opposing teeth in the intercuspal position
The lingual cusps of the upper posterior teeth and the buccal cusps of the lower posterior teeth
what are non functional cusps?
Cusps that do not occlude with the opposing teeth in the intercuspal position
The buccal cusps of the upper posterior teeth and the lingual cusps of the lower posterior teeth
what is fossa?
Depression or concavity on tooth surface
Functional cusp of a tooth contacts the fossa of the opposing tooth
what is ICP contacts?
The lingual cusp of an upper molar contacts the fossa of a lower molar
The buccal cusp of a lower molar contacts the fossa of an upper molar
what is angles classification?
class I
Class II div 1
Class II div 2
Class III
what is overbite?
vertical overlap of incisors
what is overjet?
Relationship between the upper and lower teeth in a horizontal plane
what is crossbite?
Cross bite is a condition where one or more teeth may be abnormally malpositioned buccal or lingually or labially with reference to opposing teeth
what is anterior open bite?
Lack of vertical overlap of anterior teeth when posterior teeth in full occlusion
what is posterior/lateral open bite?
Failure of contact between the posterior teeth when the teeth are in full occlusion
what is canine guidance?
Mandible moves to the left (working side)
Contact only between the canines
No posterior tooth contacts (a space)
This is what’s known as a mutually protected occlusion
what is gold standard of mutually protected occlusion?
Canine guidance
PoNo non-working/working side contacts
No protrusive interferences
sterior disclusion in lateral excursions
what is group function?
Mandible moves to the left (working side), multiple teeth in contact on the left
Bilateral group function frequently seen in toothwear
what are occlusal interferences?
Undesirable tooth contacts that may produce mandibular deviation during closure to ICP or may hinder smooth passage to and from ICP
what are types of occlusal interferences?
Working side
Non working side
Protrusive
what is protrusive interference?
any posterior contact during protrusion
why avoid posterior contacts?
Teeth are designed to absorb heavy forces in the direction of the long axis of the tooth
Most teeth are not designed to absorb significant lateral forces…………generated by occlusal interferences
Musculature gets a rest as less activity if not undesirable posterior contacts
Occlusal trauma and undesirable tooth movements
what is eccentric bruxism?
The parafunctional grinding of teeth
An oral habit consisting of involuntary rhythmic or spasmodic or functional gnashing, grinding or clenching of teeth in other than chewing movements of the mandible which may lead to occlusal trauma
what is centric bruxism?
Clenching: The pressing and clamping of the jaws and teeth together. Frequently associated with acute nervous tension or physical effort
what are clinical signs and symptoms of bruxism?
Toothwear
Fractured restorations
Tooth migration
Tooth mobility (Often in absence of periodontal disease)
Muscle pain and fatigue
Headache
Earache
Pain and stiffness in the TMJ and surrounding muscles
what re types of toothwear?
Multifactorial
Abrasion
Attrition
Erosion
Abfraction
what is occlusal trauma?
Injury resulting in tissue changes within the attachment apparatus, including periodontal ligament, supporting alveolar bone and cementum, as a result of occlusal force(s)
what is it when occlusal trauma is primary?
intact periodontium
what is it when occlusal trauma is secondary?
reduced periodontium
what is it when occlusal trauma is fremitus?
palpable or visible movement of a tooth when subjected to occlusal forces
what do you do during an examination checklist for occlusion?
- incisor relationship
- guidance
- overjet/overbite
- ICP contacts
- working/non-working/ protrusive contacts
- pathology
