Endo/Restorative Flashcards
What three criteria must be fufilled before the root canal system of a tooth can be obturated?
* Asymptomatic, not TTP
* The canal must be able to be dried
* Full biomechanical cleaning
Give the steps used in a pulpotomy
* Remove all caries
*Cut access cavity into pulp chamber
*Remove roof of pulp chamber
*Arrest bleeding from root canal orifices using ferric sulphate
*Ferric sulphate saturated CWP packed into pulp chamber and left for 3-4 minutes
*Check for haemostasis. If not achieved, repeat. If still not achieved, consider pulpectomy/extraction
*Remove CWP
*Fill pulp chamber with thick mix of ZOE
*Restore tooth with SSC
Give the steps used in a pulpectomy
*Remove caries
*Cut access cavity
*Clean canals with k-file. Stopper set at 2mm short of WL
*Irrigate canals
*Dry canals with paper points
*Deliver vitapex into canals (stopper set on delivery system at 2mm short of WL)
*Fill pulp chamber with thick mix of ZOE
*Restore tooth with SSC
Give 3 constituents of GP in addition to gutta percha
Zinc oxide. Radiopacifiers. Plasticisers.
What is the function of a root canal sealer when used with GP cones?
Fills voids and irregularities in canal, lateral canals and between GP points. Seals space between dentinal wall and core. Lubricates during obturation.
Give three generic types of sealer that are commonly used in root canal obturation
Zinc oxide eugenol
Glass ionomer
Epoxy resin sealers
Calcium silicate
What concerns do patients commonly have about the use of amalgam?
* Aesthetics
* Discolouration of teeth
* Mercury poisoning
*Affects foetal development in pregnancy
* Environmental impact
* Radiotransmitter
* Metal allergies
State what reassurance you could give a patient about the safety of amalgam
* 350-400 surface amalgam restorations required to induce a mercury response
* Amalgam is a compound with other elements and therefore more stable than elemental mercury
* It is a historic material that has been used for many many years
* The practice has a safe waste disposal system
What aspects of cavity preparation ensure caries is adequately removed?
* Remove the enamel to identify the maximal extent of the lesion at the ADJ and smooth the enamel margins
* Progressively remove peripheral caries in dentine from the ADJ first, then circumferentially deeper only then remove deep caries over the pulp
What aspects of cavity preparation ensure the finished restoration margins are cleansable?
No overhangs
Smooth margins
Smooth occlusal surface
Describe the mechanism by which resin composite bonds to enamel
Micromechanical retention of composite to enamel after acid etch
Describe the mechanism by which resin composite bonds to dentine
Removal of the smear layer (1-5 microns), decalcifies dentine to expose the collagen network
Dentine coupling agent; hydrophillic end sticks to dentine through penetration and micromechanical retention into dentine tubules and exposed collagen. Hydrophobic end bonds to the resin in the adhesive
What are the ideal properties of a denture base?
Dimensionally accurate
High softening temperature
High hardness/abraision resistance
High thermal conductivity
Non toxic
Biocompatible
High proportional limit
High transverse strength
High fatigue strength
High impact strength
Easy/inexpensive to manufacture/repair
What are the constitutes of PMMA
Powder; Benzoyl peroxide (initiator), PMMA particles, Plasticisors, pigments, co-polymer
Liquid - Methacrylate monomer (polymerises), hydroquinone (inhibitor), co-polymer
Give four possible faults during production of acrylic denture and why they occur
Contraction porosity; too much monomer, insufficient pressure, insufficient excess material
Gaseous porosity; monomer boiling in bulkier parts of the denture
Granularity - not enough monomer
Crazing - internal stresses due to fast cooling rate
Give four advantages to using co/cr as a denture base
Less bulky
High YM (rigid)
High thermal conductivity
Radiopaque
High softening temperature
Give two disadvantages to co/cr as a denture base
More difficult to make
More expensive to make
More difficult to add teeth
Aesthetics
What undercuts are required for clasps of ss, gold and co/cr?
ss 0.75mm
gold 0.5mm
co/cr 0.25mm
What are the ideal properties of an impression material?
Low viscocity
High wettability
High tear strenght
100% elastic recovery
Biocompatible
Not unpleasant taste/smell
Convenient working and setting times
Dimensionally stable
Compatible with cast material
Inexpensive
Name 2 non elastic impression materials
Impression compound
Impression paste
ZOE
Name 4 elastomers
Polyether (impregum)
Silicones (addition and condensation)
Polysulphide
Name 2 hydrocolloids
What are the constituents of Alginate?
Sodium alginate
Calcium sulphate
Trisodium phosphate
What is the setting reaction of alginate?
Sodium alginate + calcium sulphate = sodium sulphate and calcium alginate
Give 2 advantages and 2 disadvantages of alginate
Nearly elastic
Accuracy ok
Easy to use
Acceptable taste and smell
Non toxic
Cheap
Poor tear strength
Storage; syneresis and imbibition
Give 3 advantages of elastomeric impression materials over alginate
Better accuracy
Better tear strength
Better surface detail reproduction
Better impression life - doesnt dry out
Limited permanent deformation
What is the composition of GI?
Powder; silica, aluminia, calcium fluoride, aluminium fluoride
Liquid; Polyacrylic acid (forms matrix), tartaric acid (ease of use)
What is the setting reaction of GI?
Acid-base reaction
- Dissolution - acid splits and realeases hydrogen
- Gelation - calcium ions form crosslinks, bivalent
- Hardening - aluminium forms trivalent bonds
Setting takes 30 minutes to 7 days
Give four uses for GIC
Luting cement
Temp restoration
Definitive restoration
Lining material
Fissure sealant
Give 4 properties of GIC
Fluoride release
Chemical bond
Low solubility/insoluble
Poor aesthetics
Mechanical properties ok
Handling good in moisture
Thermal expansion similar to dentine
How can a hypochlorite accident be prevented?
Careful preop radiographic assessment - ensure no open apices
Provide apron and eye protection
Dental dam
Use chlorhexidine to check integrety of dam
Ensure all syringes are labelled correctly
Don’t use LA; to assess if there is a perforation
Pre endo tooth build up, build up walls of fractured teeth
Do not wedge needle into canal
Silicone stopper on needle 2mm short of WL
Depress plunger with index finger rather than thumb
What are the options for replacing a central incisor fractured to the gingival margin at short notice?
Adhesive cantilever with fractured tooth as pontic
Provisional overdenture
Provisional post crown
Vacuum formed splint with tooth
Name 3 post materials
Gold
NiCr
Ceramic
Titanium
Carbon fibre (not in anterior teeth)
SS (temporary only)
Give 6 methods for removing a fractured post
ultrasonic vibration
Masseran kit
Cut out for fibre posts
Stieglitz forceps
Eggler post remover
Sliding hammer
What are the 6 clinical signs of erosion?
Loss of surface detail
Smooth or polished surfaces
Cupping (preferential dentine wear)
Raised restorations above tooth surfaces
Translucent incisal edges
What are four indications for the size of a post?
4-5mm GP remaining
Post <1/3 of root width
Post to crown ratio >1:1
At least half of the post length into the subcrestal root
1mm of circumfrential dentine/root
What materials can be used to cement a post?
GI luting cement
Composite resin luting cement
What are some causative factors of erosion?
Extrinsic - diet (carbonated drinks/alcohol/highly acidic foods) alcohol containing mw, asthma inhaler
Intrinsic - GORD, builimia nervosa, persistent vomitting
Pt congenitally missing 22, 23. Give problem relating to aesthetics
Pt may be being teased due to gap
Pt may be psychologically affected by missing teeth
What 3 general things would a GDP check before referring pt re replacement of congenitally missing teeth?
Periodontal status
Smoking status
Diabetes
Osteoperosis
Bisphosphonates
Blood clotting disorder
Signs and symptoms of reversible pulpitis?
Short, sharp pain (A beta and A delta fibres, hydrodynamic microleakage stimulation)
Stops when stimulus is removed
Not TTP
Pain to cold
Well localised
How is reversible pulpitis managed?
Removal of caries, other causative factors, restore
Signs and symptoms of irriversable pulpitis
Lingering pain after removal of stimulus
Dull ache (c-fibres)
Spontaneous pain
Sleep distrupted
Pain with heat
More generalised pain
How is irreversible pulpitis mangaed?
RCT/extract
Patient had large composite placed due to secondary caries. Pt still having sensitivity a week later, give reasons for transient sensitivity to thermal stimulus/biting
Insufficient cooling on prep
Uncured resins entering pulp
Pulp exposure
Fluid from tubules occupying space under restoration
Restoration high
Abraision
Gingival recession
Perio disease
Acid erosion - GORD
Dental bleaching
Smoking
Bruxism
Deep cavity
Give 5 restorative management features to prevent post comp placement pain
Application of strontium TP
Provide pt with splint
Check occlusion
HPT
Gingival augmentation
Application of F varnish 22,600ppmF
Use lining RMGI/vitrebond
Pulp cap
Indirect restoration
Stepwise excavation
Pt has gold post and core that has debonded several times, give potential reasons why
Post fractured
Core fractured
Root fractured at post level when not attributed to trauma
Untreatable caries
Traumatic fracture
Furcation perforation
Inadequate moisture control
How is erosive toothwear managed?
Removal of cause; diet advice, ohi
High fluoride TP
Cover sensitive exposed dentine with seal and protect, GI, composite
Rule out medical cause, treat GORD, refer to GP
Recommend use of straws
What factors does an implantologist consider before placing an implant?
Smoking status
Bone quality and quantitiy
OH
Pt motivation
Occlusion
Aesthetics
What bone dimensions are required for an implant?
1.5mm horizontal bone round implant
3mm between implants
>5mm space for the papilla between bone crest and contact point
Assessed with CBCT
7mm spacing
2mm from adjacent structures ie sinus/IAC
How can you check if a brigde has debonded?
Probe
Check visually
Check mobility
Push and check for air bubbles
Floss
What factors should be taken into consideration before placing a bridge?
Occlusion
Parafunction
Length of span
Abutment health - caries/perio
OH
Quality of enamel
RMGI liner vs GI liner?
On demand set
Higher mechanical strength
Lower solubility
What are four properties of GI?
Fluoride release
Chemical bond
low solubility/insoluble
Mechanical properties ok
Handling good in moisture
Thermal expansion similar to dentine
Poor aesthetics
What are the five designs of pontic and retainer?
Wash through pontic,
Dome pontic
Modified ridge lap pontic
Full saddle pontic
Ovate pontic
In fixed pros treatment planning, give the order of carrying out an examination
E/O;
TMJ
MoM
Lymph nodes
Symmetry
Lips (vermillion border, commissures, smile line)
I/O
STE; buccal mucosa, tongue, FoM, palate, lips
BPE
Teeth;
Missing, restorations, caries
Occlusion;
Excursions, canine guidance, group function, interarch space, intertooth space
What special investigations are taken into consideration in the planning of fixed pros treatment?
Sensibility testing (EPT, ECl)
Radiographs; caries, restorability, pathology, bone levels, restorations, abutment teeth
Study models
Facebow
Diagnostic wax up
Additional; diet diary, PGI, Full mouth perio chart, Clinical photos, microbiology, biopsy, haematology
Run through the order of treatment planning
IMMEDIATE
Relief of acute symptoms
Consider endo/extractions
Consider immediate denture/bridge
INITIAL (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 pros
RE-EVALUATION
Re-assessment of perio status, confirm denture/bridge design
RECONSTRUCTIVE
Perio surgery
Fixed and removable pros
MAINTENANCE
Supportive perio care and review of restorations
When should veneers not be considered?
Poor OH
High caries rate
Interproximal caries/unsound restorations
Gingival recession
Root exposure
High lip line
Extensive prep
Labially positioned, severe rotation, overlap
Extensive TSL/insufficient bonding area
Heavy occlusal contacts
Severe discolouration
What are the indications for inlays/onlays?
Tooth wear cases (increase OVD)
Fractured cusps
Restoration of root treated teeth
Replace failed direct restorations
What are the contraindications for inlays/onlays
Active caries/perio disease
Time constraints
Cost
Indications for crowns
Protect weakened tooth structure
To improve or restore aesthetics
For use as a retainer for fixed bridgework
When indicated by the design of an RPD (rest seats, guide planes, clasps)
To restore tooth funtion
Contraindications for crowns
Active caries/perio disease
More conservative options are available
Lack of tooth tissue for preparation
Unable to provide post and core
Unfavourable occlusion
Indications for bridges
Aesthetics
Occlusal stability (prevent tilting or over eruption of adjacent/opposing teeth)
Restore function (mastication, speech, wind instrument players)
Perio splinting
Restoring OVD
Pt preference
What discussion should be had with a patient for informed consent for fixed pros?
invasiveness/reversibility
Likely longeviy and success rates
Time involved
Cost
Alernative options
What treatmnet involves
Why it’s necessary
Consequences of no treatment
What is an abutment
tooth which seves as an attachement for a bridge
What is a pontic
The artificial tooth which is suspended from the abutment tooth/teeth
What is a retainer?
The extra or intracoronal restorations that are connected to the pontic and cemented to the prepared abutment tooth
What is a connector?
Component which connects the pontic to the retainer
What is the edentulous span?
Space between natural teeth that is likely to be filled by a bridge or partial denture
What is a saddle?
Area of the edentulous ridge over which the pontic will lie
What is a pier
An abutment tooth which stands between and is supporting two pontics, each pontic being attached to a further abutment tooth
What are some advantages of a conventional bridge?
Robust design
Max retention and strength
Abutment teeth splinted together (perio cases)
Can be used in longer spans
Lab construction straight forward
What are some disadvantages of conventional bridges?
Difficult prep (parallel prep needed)
Must be minimally tapered
Common path of insertion
Requires removal of tooth tissue
What gingival clearance is needed for an adheive abutment?
0.5mm
What are the requirements of an adhesive abutment?
Ideally sound enamel
Composite is ok, consider replacing prior to prep
Amalgam; compromised bond to chemically cured composite cement. Consider replacing
Retainer wing should be 0.7mm thick
What is the 5 year survival rate for bridges?
Depending on design 80-95%
What materials can be used in the manufacture of bridges?
All metal (gold, Nickel, co/cr)
Metal-ceramic
All ceramic (zirconia, lithium disilicate)
Ceromeric (BelleGlass)
What materials are used in the cementation of bridges/crowns?
All metal or metal ceramic; aquacem (gi luting cement) or Rely-x (RMGI)
Adhesive/resin bonded; Panavia (anaerobic dual cure resin cement)
All ceramic (NEXUS; dual cure resin cement)
What ‘rules’ apply to distal cantilever bridges?
Avoid if possible
Concern that occlusal forces on pontic will produce leverge forces on abutment tooth causing it to tilt
May consider distal cantilever from premolar abutment if unopposed or opposed by denture
