Restorative Flashcards
Reasons for treating tooth loss
- aesthetics
- function
- speech
- maintenance of dental health
advantages of resin bonded bridges
minimal or no preparation
no la needed
less costly
less surgery time
can be used as a provisional restoration
if fails - usually less destructive than alternatives
indications for resin bonded bridge
young teeth
- less destructive
good enamel quality
large surface area of abutment tooth
minimal occlusal load
good for single tooth replacement
simplify partial denture design
resin bonded bridge disadvantages
rigorous clinical technique
metal shine-through
chipping porcelain
can debond
- high chance of debonding again
- occlusal interference
no trial period possible
resin bonded bridge contraindications
insufficient or poor quality enamel
long spans
excess soft or hard tissue loss
heavy occlusal force e.g. bruxism
poorly aligned, tilted or spaced teeth
contact sports?
bridges - treatment planning
history
establish habits e.g. bruxism
examination
clinical
- Perio status
- radiographs
- dynamic occlusal relationships
study models
- mounted on semi-adjustable articulator
- consider diagnostic wax ups
adhesive bridge - prep (if required)
rest seats
- posterior teeth
cingulum rests
- anterior teeth
supra gingival chamfer finish line -0.5mm
prep should ideally remain in enamel
how to fit an adhesive bridge
try in retainer
- check fit and aesthetics
(retainer should have already been sandblasted by lab)
add silane coupling agent to retainer
isolate tooth and etch
wash and dry
add primer for 30 seconds then air dry
apply composite luting cement to retainer
fit retainer and remove excess cement
apply oxygen inhibitor (oxyguard II) around margins for 3 minutes and wash off OR light cure for 20 seconds
what luting cement is used for an adhesive bridge?
Panavia 21 EX (anaerobic cure composite luting cement)
RBB 5 year survival
80%
disadvantages of conventional fixed-fixed bridge
preparation difficult
- parallel tooth preparations needed
common path of insertion for abutments
removal of tooth tissue
- danger to pulp
conventional cantilever bridge - advantages
conservative design
- compared to fixed-fixed conventional
- lab construction straightforward
- no need to ensure multiple tooth preparations are parallel
causes of tooth wear
attrition
abrasion
erosion
abfraction
features of attrition
- attritive lesions found in occlusal and incisal contacting surfaces
- early appearance is polished facet on cusp or slight flattening of an incisal edge
- progression leads to reduction in cusp height and flattening of occlusal planes
- can be a shortening of the clinical crown of the incisor and canine teeth
abrasion - common clinical features and signs
site and pattern of tooth loss related to abrasive element
most common is labial/buccal, cervical on canine and premolar teeth
v shaped or rounded lesions
Sharp margin at enamel edge where dentine is worn away preferential
erosion - define
loss of tooth surface by chemical process that does not involve bacterial action
- most common cause of pathological tooth wear
what are the intial/early signs of tooth erosion?
enamel surface affected
- loss of surface detail
- surfaces becomes flat and smooth
- typically bilateral, concave lesions without chalky appearance of bacterial acid decalcification
tooth erosion - later stages signs
late stages
- dentine becomes exposed
- wear of dentine leads to ‘cupping’ of incisal edges of anteriors and occlusal surfaces of molars
abfraction - define
loss of hard tissue from eccentric occlusal forces leading to compressive and tensile stresses at the cervical fulcrum of the tooth
tooth wear - special tests
sensibility testing
radiographs
articulated study models
intra oral photographs
salivary analysis
diagnostic wax up
dietary analysis
tooth wear - immediate treatment options if patient presents with symptoms
deal with pain/sensitivity
- desensitising agent
- fluorides
- bonding agents
- GIC coverage of exposed dentine
pulp extirpation
- if wear has compromised pulpal health
smooth sharp edges
- prevents trauma to cheeks and tongue
extraction
- pain from unrestorable/non-functional tooth
TMJ pain
- important in attrition - acute symptoms need to be controlled
tooth wear - initial phase treatment options
stabilise existing dentition
treat caries
treat perio condition
oro-mucosal
once you have a diagnosis and identified primary cause:
- establish preventative regime
treatment without prevention will fail
tooth wear prevention: abrasion
remove foreign object or substance involved
change toothpaste
alter brushing habits
change habits
- nail biting
- wire stripping
- piercing biting
- pen chewing
How to create space to treat maxillary anterior tooth wear
increase OVD
- multiple posterior extra coronal restorations
- downsides - complex, destructive and expensive
occlusal reorganisation from ICP to RCP
- complicated, can be destructive, specialist treatment
surgical crown lengthening
- doesn’t really create more space
elective RCT and post crowns
- very destructive
conventional orthodontics
- lengthy treatment
what is the Dahl technique?
method of gaining space in cases of localised tooth wear
originally a removable CoCr anterior bite plane
- now carried out in composite (better aesthetics, better compliance, easier to adjust)
covering palatal survives and allowing occlusion on raised cingulum
results in posterior dislcusion and increase in OVD of 2-3 mm
occlusal contacts only on incisor/canine teeth
Dahl technique How is spaced gained?
over a period of 3-6 months space gained between incisors
anteriors intrude
posteriors erupt
results in space between upper and lower anteriors allowing restoration without need for occlusal reduction
Dahl technique - effectiveness
variable rate of affect - faster in younger patients
if no movement in 6 months = won’t work
>90% success rate
occlusion initially disorganised but reestablishes with time
Dahl technique - contraindications
active periodontal disease
TMJ problems
post orthodontics
bisphosphonates
dental implants
existing conventional bridges
Dahl technique is the treatment of choice to treat…
localised anterior tooth wear
contraindications for buildups for anterior wear
short roots
reduced periodontal support due to periodontal disease
why is lower anterior tooth wear more difficult to treat than upper anterior tooth wear?
less enamel
smaller bonding area
how is a clear vacuum form matrix used in composite build ups?
alginate impression taken
diagnostic wax up
impression of this poured in stone
- vacuum formed clear plastic matrix formed on this
cut to size and used as mould for build-up
Give examples of Veneer use cases
aesthetic improvement
change tooth shape/colour
correct peg laterals
space and diastema closure
align labial surfaces of teeth
basic principles of veneers
caries removal
keep as much sound tooth tissue as possible
maintain pulpal and periodontal health
restore form and function
longevity
aesthetics
occlusal stability
must be cleanable
types of veneers, and options for materials
palatal
- porcelain
- lithium disilicate
- composite
- zirconia
- gold
- nickel-chromium
buccal
- porcelain
- lithium distillate
- composite
- zirconia
palatal veneers - uses
tooth wear
- erosion
increasing OVD
Dahl approach
buccal/labial veneer contraindications
uncontrolled caries and periodontal disease
poor oral hygiene
excessive spacing
severe malocclusions
- malpositioned teeth
bruxism
insufficient enamel
severe discolouration
downsides of buccal/labial veneers
higher failure rate if involves dentine or other restorations
lute and leakage
cyclical replacement
technique sensitive
labial/buccal veneers - cases to take additional care with
lower incisors
gingival recession
root exposure
high smile lines
heavy occlusal contacts
previous failed veneers
indications for external bleaching
age related darkening/discolouration
mild fluorosis
post smoking cessation
tetracycline staining
bleaching - warnings for patient
sensitivity
relapse and retreatment
restoration colour
allergy
might not work or only work partially
compliance with regime
internal non-vital bleaching indications
non vital tooth
adequate RCT
no apical pathology
internal bleaching contraindications
heavily restored tooth
better with crown or veneer
staining due to amalgam
internal non vital bleaching potential complications
external cervical resorption
combination bleaching for non vital teeth (inside out bleaching) - outline steps
make bleaching tray with a palatal reservoir
bleach placed in access cavity and in tray
replaced frequently over about a week
What are the advantages of using an inlay over a direct restoration?
- superior materials and margins
- won’t deteriorate over time
Extrinsic causes of tooth discolouration
- smoking
- tannins e.g. tea, coffee
- chromogenic bacteria
- chlorohexidine
- iron supplements
intrinsic causes of tooth discolouration
- fluorosis
- tetracycline
- non-vitality
- amalgam
- cystic fibrosis - grey teeth
- sickle cell anaemia
factors affecting external tooth bleaching
- time
- cleanliness of tooth surface
- concentration of solution
- temperature
external vital bleaching - warnings to patients
- sensitivity
- relapse
- won’t bleach restorations
- allergy
- might not work
- compliance with regime
in office external bleaching technique
- thorough clean of teeth
- rubber dam or at least gingival mask
- apply bleaching gel to tooth
- apply heat and light
- wash, dry and repeat
- takes 30 mins to an hour
internal non-vital bleaching Indications
- non-vital tooth
- adequate RCT
- no apical pathology
what are the minimum requirements for a legal prescription?
prescriber must write clearly in black pen
each individual letter must be visible
must contain the following details:
- name and address of patient
- name of drug
- form of drug e.g. SR tablet
- strength
- dose the patient is supposed to take, and frequency
- total quantity of the preparation
- prescribers signature, registration number and contact details
- date
how long is a standard NHS prescription valid for?
6 months
how long is an NHS prescription for a controlled drug valid for?
28 days
What is the ideal operator seating position? give the features of this position
balanced position
- approx 90 degree angle at the hip and knee
- thighs roughly parallel to floor
- feet on floor, back and neck upright
- shoulders relax
- move with back, do not bend, twist or stoop
How is direct aspiration done?
aspirator placed adjacent to tooth being treated
best place slightly distal to tooth
bevel adjacent to tooth
remove any excess fluid or debris at back of patients mouth
when is indirect aspiration necessary?
if the aspirator obscures view of the operator
- upper anterior region
What can be used for soft tissue retraction?
aspirator
dental mirror
cheek retractor
3 in 1 syringe
tongue depressor
Name and describe
Protrusion
condyle moves forwards and downwards on articular eminence
only incisors +/- canines touch
no posterior tooth contacts
name and describe
Intercuspal position (ICP)
tooth position regardless of condylar position
the comfortable bite
maximum interdigitation of teeth
intercuspal position is also known as…
centric occlusion
name and describe
Edge to edge
teeth slide forward from ICP guiding on palatal surfaces of anterior teeth
incisal edges of upper and lower incisors touch
Name and describe
Maximum opening (T)
no tooth contacts
mouth wide open
full translation of condyle over articular eminence
Name and describe
retruded axis position
no tooth contacts
most superior anterior position of condylar head in fossa
terminal hinge axis
Name and describe
Retruded contact position
first tooth contact when mandible is in retruded axis position
approx 1mm anterior to RCP in 90% of population
most reproducible position
what are functional cusps?
cusps that occlude with the opposing teeth in ICP
- lingual cusps of upper posterior teeth and buccal cusps of lower posterior teeth
What are non-functional cusps?
cusp that do not occlude with the opposing teeth in the intercuspal position
- buccal cusps of upper posterior teeth
- lingual cusps of lower posterior teeth
What is canine guidance?
when mandible moves to working side;
- only canines contact
- no posterior teeth contact
What is group function?
when the mandible moves to the working side;
- multiple teeth contact
Types of occlusal interference
working side
non-working side
protrusive
types of articulator
simple hinge
average value
semi-adjustable
fully adjustable
temporisation options for a resin bonded bridge
consider RPD
if prep into dentine and tooth becomes sensitive:
- cover with layer of dentine bonding agent
- or high fluoride toothpaste
What is a fixed-moveable bridge?
a bridge that has a rigid connector at the distal end of the Pontic and a moveable connector mesially
- allows some vertical movement at the mesial abutment tooth
advantages of a fixed-movable bridge
preparation don’t require common path of insertion
more conservative of tooth tissue
allows minor tooth movement
may be cemented in 2 parts
disadvantages of a fixed-movable bridge
length of span limited
laboratory construction more complicated
possible difficulty in cleaning beneath moveable joint
can’t contract provisional bridge
what is a hybrid bridge?
one retainer = conventional preparation
other retainer = minimal preparation
- adhesive/resin retained
what is a spring cantilever bridge?
one Pontic attached to end of a metal arm that runs across palate to a ridgid connector on the palatal side of a retainer
spring cantilever - cases where this may be necessary
spacing present between upper incisors
adjacent teeth unrestored
posterior tooth would provide suitable abutment
- large crown/restoration
disadvantages of spring cantilever
can only be used to replace upper incisors
difficult to clean beneath palatal connector
may irritate palatal mucosa
difficult to control movement of Pontic
general contraindications for bridgework
uncooperative patient
medical history
poor oral hygiene
high caries rate
periodontal disease
large pulps (conventional)
local contraindications for bridgework
high possibility of further tooth loss within arch
prognosis of abutment poor
length of span toot great
ridge form and tissue loss
tilting and rotation of teeth
degree of restoration
periapical status
periodontal status/bone loss
What is a wash-through Pontic and when would it be appropriate?
a Pontic that makes no contact with soft tissue
- functional rather than for appearance
- consider in lower molar area
What ridge surface designs are available for bridge poetics?
wash-through
dome shaped
- useful in lower incisor, premolar or upper molar area
modified ridge lap
- buccal surface looks like tooth
- lingual surface cut away
- problems with food packing on lingual surface
ridge lap/saddle
- greatest contact with soft tissue
- take care not to cause blanching or displace soft tissue
ovate
- excellent aestehtics
- more difficult to clean
why do preparations for a fixed-fixed conventional bridge need to be parallel?
provides a common path of insertion
increased retention
why are distal cantilevers less desirable?
occlusal forces on Pontic may produce leverage forces on abutment tooth causing it to tilt
basic principles of onlays and posterior crowns
caries removal
keep as much sound tooth tissue as possible
maintain pulp and periodontal heath
restore form and function
longevity
aesthetics
occlusal stability
cleanable
thorough case assessment
advantages of a posterior crown over an onlay
retention and resistance often better
easier technically
covers all cusps
aesthetically sound
disadvantages of posterior crowns
more destructive than onlay
often sub gingival margins
cannot access for sensibility testing
need a sound crown core
metal ceramic crown prep dimensions
1.5mm occlusal reduction
1.3mm buccal shoulder margin
- 0.5mm above gingival margin
0.5mm lingual chamfer margin
0.5mm functional cusp bevel
Give 4 uses for a face bow
mounting the upper cast
transferring the relationship between the maxillary teeth and axis of rotation from the patient to the articulator
positions the upper cast vertically
transfers the angulation of maxillary occlusal plane in relation to a horizontal reference plane
