Crown And Bridge Anterior Teeth Flashcards
What is a provisional crown?
Made to last for a longer period eg whilst periodontal treatment carried out
What is a temp crown?
Made to only last a short time
What are the biological requiements for temp crown?
BAM
Biological: protect prepared dentine, prevent gingival overgrowth, prevent over eruption and tilting of adjacent teeth
Aesthetics: good surface topography and shade
Mechanical: strong enough to withstand forces of occlusion and mastication
How can temp crowns be made?
Chair side or preformed crown
Preformed: polycarbonate for canine, incisor and premolar
Aluminium for molar teeth: aluplast
Tin alloy : ion
What are the advantages of tooth coloured crowns?
Aesthetics
What are the all tooth coloured crowns?
All porcelain
Lab constructed composite
Resin/detine bonded
What are the non all tooth coloured options for anterior crowns?
PFM
How can all porcelain crowns be made?
Conventional build up on platinum folk or refractory model
CAD/CAM coping with conventional build up
CAD/CA! Without coping eg Cerec
Pressed porcelain
Glass infused ceramics
Cast glass ceramic
Which technqie is commonly used for all ceramic crowns?
Conventional build up on platinum foil
Which technqie is commonly used for veneers?
Conventional buildup on refractory model
What is the purpose of the foil I the porcelain?
Platinum foil laid down and then alumina or porcelain core used for strength
Platinum foil removed after glazing and prior to cementation
What type of joint is used for the platinum foil?
Tinners
How can you build up the core for the porcelain crowns?
Using a paint birth or a le cron handle
What is the technique called when you leave the platinum foil on ?
Mac clean sced techqnie
The pt foil is tin plated and allows porcelain to bond to foil
What are the options for discoulored anterior teeth?
Hydrochloric acid pumice microabrasion Non Vital bleaching Vital bleaching Localised composite veneers Crown
What can be the cause of discoloured tooth?
Intrinsic or extrinsic
Intrinsic: caries, erosion ingestion, trauma, non vital, neonatal jaundice, genetic
Extrinsic: plaque, calculus, mouth wash, smoking,diet, restorations
What are the manamagemt aims for discoloured anterior teeth?
Restore aesthetics Restore function Resolve sensitive t Preserve tooth Respect periodontal health
How does hydrochloric acid - pumice work?
This improves discolouration limited to outer enamel only
How much enamel is removed in microabrasion and pumice?
Less than 100 micrometers
What is the technique to microasbriaon?
Vitality test, x ray and photos
Clean dry and isolate
Protect soft tissues with sodium bicarbonate
18% HCL and pumice 5 sec application using slow rotary or wooden stick
Max of 10 times 5 secs
Fluoride drops for 3mins
Oldish for 1 min with soflex
When is micoabrsairon indicated?
Fluorisis
Idiopathic speckling
Post ortho demin
Well demarcated brown patch before veneer
White or brown surface staining eg turner teet
When shoud you see an improvement in colour with the microabrasion?
1/12
Which colour staining is more easily removed with microabrasion?
Brown
How do white stains improve?
Due to optical changes of aprismatic enamel
T/F there is an association between caries and prolonged thermal sensitive and microabrasion?
F
What kit do you need for microabrasion?
Pumice Rubber am and copalite varnish Bicarbonate tsoda 18% HCL or 37% phosphoric acid Non acid fluoride Fine soflex disk Fluoridated tooth paste
When is non vital bleaching indicated?
Non vital discoloured teeth
What causes the discolouration in non vital teeth?
Diffusion of Hb products from necrotic pulp tissue
What are the requirements for non vital bleaching?
Well condensed GP
No clinical evidence radiographic signs of Periapical disease
How do you perform non vital bleaching?
Pre op X-ray
Clean tooth and note shade
Access pulp chamber and remove filling to level of dento gingival
1mm zinc phosphate placed on top
Etch tooth with 37% phosphoric acid for 30-60secs
Mix bleaching agents and cover with GIC. For 1 week
WHen is non vital bleaching not effective?
Heavily restored teeth
Staining due to amalgam
21% failure rate
How often should you do the non vital bleaching?
Every week once a week until over bleached
How kong should you leave non setting CaOH in cavity for?
2 weeks
How should you restore the cavity?
With white GP and composite
When should you abandon non vital bleaching?
If no improvement after 3 times
What kit do you need for non vital bleaching?
Rubber dam Zinc phosphate 37% phosphoric acid 30 volume hydrogen peroxide Sodium perborate Cotton wool and GIC Composte resin
What type of resorption can non vital bleaching lead to?
Cervical
How do we prevent cervical resorption in non vital bleaching?
1mm zinc phosphate at neck of tooth
CaOH dressing to eradicate pulpal inflammation
What are the options for vital bleaching?
Chair side or night time
What percentage HP can be used for vital bleaching?
Up to 6%
When is chair side bleaching implicated?
Mild fluorosis
Ageing
Sclerosed pulp chamber
What happens to the hydrogen peroxide applied to the tooth in vital bleaching?
Activated with a light source of heat
What is the legislation behind vital bleaching?
Before 2012 could only use 0.1% HP one can use up to 6%
What is the process of home bleaching?
For each cycle,first cycle must be done by practitioner and for over 18 only
Can use 10% carbamine peroxide gel which breaks down to 3% HP and 7% urea which both diffuse through enamel and dentine
What are the concerns with vital bleaching?
- Trace amounts of phosphoric and citric acid might lead to low pH and demin
- initial decrease in bond strength of composite which resolve over 7 days
- possible cytotoxic
Why is thre an initial decreases in composite bond strength?
Due to residual O2
What is vital bleaching cytotoxic to?
Vascular endothelium
What are the advantages and dis of localised resin based composite for discoloured anterior teeth?
AD
Useful for demarcated lesion
Dis: marginal staing, accurate colour match and reduce composite translucent and need good quality enamel
When are veneers indicated?
Discolouration,
Diaestema
Mal positioned tooth
Large restoration a
When are veneers contra indicated?
Poor quality tooth for bonding
Teeth to buccal in the arch
Heavy occlusal loading
What is a good intermediate before placing porcelain veneers?
Composte resin
Good for children since have large pulp and immature gingival contour
For adults can be used as permanent but reversible and can be used a Dahl
When are porcelain veneers indicated?
Adults
T/F composite resins can be used directly ?
T
Lab made or direct
What is the problem with composte veneers?
Increased labio Palatal bulk can be detrimental to gum health
What are the disadvantages with porcelain veneers?
Hard to repair
Abrasive
T/F porcelain veneers mask out gross discolouration?
T
How much do you prepare porcelain veneers into teeth?
0.5mm
How do you prepare the surface of the veneer?
Sand blast and the HF acid and then apply silane coupling agent
What is a RRB?
A resin bonded bridge fixed to one or more unprepared or minimalist prepared natrual teeth
What are the alternative names for RRb?
Adhesive
Minimum prep bridge
Maryland bridge
What is the history begin RRB?
1973: Rochette used metsl wings to splint periodontal compromised teeth
Tags of resins were used to retain metal wing that had perforations on
What are the advantages to RRb?
Fixed Conservative No La Short clinical time Relatively inexpensive Reversible/diagnostic
What are the disadvantages of RRB?
Aesthetic: greying of the abutment and metal showing over
Try in of bridge can be hard
Temporising can be difficult
Extensive restore teeth cannot be used
Risk of debond and failure rate higher than conventional bridge work
Risk of caries greater if partial de bond of fixed fixed design
Technqie sensitive
What are the failure rates for RRB? Reference
Djemal 1999
92% debond
4% metal fracture
2% caries
What are the indications for RRB?
Single tooth replacement ideally
Unrestored abutments
Teeth with sufficient good quality enamel
Intermediate prosthesis in young patient
What are the contras indications to RRB?
Heavily restored abutments Teeth with lack of good quality enamel Excessive occlusal loading Poor OH Diffuculty in isolation Translucent incisal edge Disastomer
What are the designs for a RRB?
Cantilever
Fixed fixed
Hybrid
What are the features of a cantilever?
Eliminate problem of partial de bond
Less expensive
Limited to replacing only single tooth
Less stress on resin lute since no differential tooth movement
What are the features of a fixed fixed?
Provide periodontal splinting
Orthodontic retention
Can restore multiple missing teeth
Needed for anything other than single premolar or anterior r
Differential movement of abutment
What is a hybrid design?
Resin retained and conventional design
Needed when one or more of abutments to be restored with conventional crown
Two testiness maybe joined by a moveable joint
What is the median survival rate for RRB? Reference
Fixed fixed 7.8 yrs
Cantilever 9.8 yrs
Djemal 1999
What are the clinical stages to RRB prep?
Sharp angles of tooth removed Bulbosities removed Guide planes No finish lines Crete bevel for incisal anterior teeth Aim for max coverage 180 degrees Consider crown lengthening Retauner extends into incisal edge and cusps Posterior teeth need extensive occlusal coverage Rigid framework
How thin can the metal be finished to in RRB?
0.1-0.5mm
How thick should the metal retainers in RRB. Be?
0.7mm minimum
How can you create space for the retainer in the RRB?
Prepare abutment
Reduce oppsing teeth
Ortho
Dahl
Which method of space creation is ideal for the Pontic? Except for which patients?
Dahl
Except: occlusally aware and periodontal compromised
Which metal allot is used for the bridge?
Ni-Cr
What tyke of cement must be used for RRB?
4-Meta or Phosohate groups
What are the future options for RRB?
Metal free made from zirconia or ceramic
Good for premolar region
What are the problems with the metal free RRB?
Need increase bulk for retainer and increased risk of fracture of Pontic
