restorative Flashcards
indications for replacing/restoring teeth
- pain
- sensitivity
- poor aesthetics
- fracture
- functional problems (mastication, speech)
- structure problems
- occlusal instability
- perio splinting
- restoring OVD
reasons to not restore/replace teeth
- Damage to tooth and pulp
- effect on periodontium
- cost
- unrestorable teeth
principles of cavity prep
Access - identify and remove carious enamel.
Remove enamel to identify maximal extent of lesion at ADJ and smooth enamel margins.
Ensure ADJ margins are caries-free
Caries management - progressively remove peripheral dentinal caries.
Remove deep caries over pulp.
Cavity modification - outline form modification and internal design modification (for chosen material)
D1
clinically detectable enamel lesions with intact surfaces
preventative care
D2
clinical detectable cavities limited to enamel
preventative
D3
clinically detecetable lesions into dentine
preventative care and restorative care
affected dentine
softened demineralised
D4
into pulp
infected dentine
softened demineralised dentine that has been invaded/contaminated by bacteria
partial caries removal
access
caries removal
removal of infected dentine where possible
definitive restoration
stepwise caries removal
access
caries removal
leave caries over pulp
temporary restoration
allow tertiary denine formation
remove temporary and remove remaining soft dentine
defintive restoration
methods of managing caries
partial caries removal
stepwise caries removal
self cleansing
direct pulp cap
pulpotomy
functional/stable occlusion
free of interferences to smooth gliding movements of the mandible with the absence of pathology
mutually protected occlusion
gold standard - canine guidance, posterior disculsion in lateral excursions, no protosive interference, no non-working side/working side contacts
working side is the side you move to
supporting cusps
cusps that occlude with opposing centric stops
palatal uppers, buccal lowers
non-supporting cusps
cusps that don’t occlude with opposing centric stops
buccal upper, lingual lower
BULL
non-supporting cusps
cusps that don’t occlude with opposing centric stops
buccal upper, lingual lower
BULL
centric stops
points on occlusal surface which meet with opposing teeth
occlusal interefernce
undesirable tooth contacts that may produce mandibular deviation during closure to ICP or may hinder smooth passage to and from ICP
Contacts that hinder smooth excursive movements of the mandible.
* Lateral obtrusive - undesirable working side contact
* Protrusive - posterior contact during protrusion
benetts angle
angle described by the orbiting condyle during lateral protrusive movements
average is 10-15 degrees
sagittal condylar angle
angle at which teh condyle descends down the glenoid fossa of the TMJ in the saggittal plane
rest position
normal position when not eating/talking
teeth slightly appart (interocclusal clearance)
TMJs in fossa
neutral, relaxed position
free way space
difference between rest position and ICP
difference between OVD and RVD
av 2-4mm
conformist
maintain existing/original occlusion
reorganised
altering existing/original occlusion (new occlusal scheme)
need pt in RCP
guidance
factors which control protrusive and excursive movements of mandible
- anterior teeth contact (incisors and canines) on working side during excurisve movement
- group function - multiple posterior teeth contacts on working side during excursive movements
- canine - disclusion of teeth on working side - except canines; and absence of non working side contacts during excursive movements
reproducible and protects posterior teeth - preferred
ideal features of occlusal contacts
3
- lower incisal edges occlude afainst upper cingulum (BSI class I)
- lower buccal cusps and upper palatal cusps occlude against fossa and marginal ridges of opposing teeth
- tripid/cusp tip to base of fossa contacts - forces directed down long axis of tooth
features of unfavourable occlusal contacts
- on cuspal inclines
- no contacts
features of normal occlusal forces
- contact only in ICP
- short duration
- light forces compared to maximum biting forces
- forces directed down long axis of tooth
- protective neuromuscular reflexes prevent injury
features of abnormal occlusal forces
and what may occur
- greater forces exerted
- longer duration
- contacts in many mandibular positions
- horizontally directed
- protective neuromuscular reflexes do not operate
may cause damage to teeth, PDL, muscles and joints
what is posselts envelope of motion
3D concept of mandible movement - a combination of border movements in a ll 3 planes (sagittal, transverse, frontal)
ICP
intercuspation
position of maximum interdigitation/intercupation
postiion of best fit between maxillary and mandibular teeth
RCP
guided tooth position in which condyle in most anterior superior position within the condylar fossa
edge to edge
incisal edge to incisal edge.
Upper and lower incisors at same coronal/frontal leve
protrusive position
occlusion when mandible maximally protruded
retruded axis position
position adopted by condyle during terminal hinge movement opening and closing
(condyles in most anterior superior position - rotation not translation)
maximum opening
when mandible maximally despressed
centric relation
mandible position when condyles are in most anterior superior position in their fossa, resting against the posterior slopes of the articular eminences with articular discs interposed
repeatable, reproducible position that can occur anywhere between retruded axis position and RCP
protrusion
jaw position when mandible maxillary protruded
SDA
dentition where most posterior teeth are missing but satisfactor function without RPD
long term occlusal stability
3-5 occlusal units left
(usually 5-5)
pair of occluding molars in occlusal unit
2
pair of occluding premolars in occlusal units
1
indications for SDA
- missing posterior teeth with 3-5occlusl units remaining
- sufficient occlusal contacts to provide large enough occlusal table
- favourable prognosis of remaining teeth
- pt not motivated to pursure more complex tx plan
- limited finances
contraindications for SDA
- poor prognosis of remaining teeth
- untreated/advanced perio disease
- pre-existing TMD
- signs of pathological wear
- significant malocclusion (class II or III)
occlusal stabilitiy definition
- stablity of tooth position relative to its spacial realtionship in occluding arches
- absence of tendency for tooth migration other than normal physiologic compensatory over time
features that can determine occlusal stablity
- absence of pathology (tooth wear, caries)
- perio support
- number of teeth in each arch
- interdental spacing
- occlusal contacts
- mandibular stability
requirements for occlusal stability
- stable contacts on all teeth of equal intensity in centric relation (balanced occlusion)
- anterior guidance in harmony with Posselt’s envelope of motion
- disclusion of all posterior teeth during mandibular protrusive movement
- disclusion of all posterior teeth on non-working side due to madnibular lateral movement
- disculsion of all posterior teeth on working side during mandibular lateral movement
purpose of facebow
used to orientate maxillary case in same relationship on articulator as maxilla is related to condyles
is a horizontal record of the hinge axis of mandible
function of articulators
- obsever occlusal relations
- provide dx wx ups and locate undercuts
mechanical devices which represent TMJ and jaw members to which casts can be attached to simtulate jaw movement
* non adjustable (hinge, av valu)
* semi-adjustable (arcon/non arcon)
* fully adjustable
adv of indirect gold restorations
- excellent strength
- good support
- good cuspal protection
- durable
- corrision resistant
- wear resistant
disadv of indirect gold restorations
- expensive
- poor aesthetics
- difficult to make
- demanding and non conservative prep
adv of indirect Vs direct composites
no polymerisation contraction stress
no cuspal flexure
adv of milled porcelain restoration
best aesthetics
good wear resistance
good retention
5 advantages veneers
improve aesthetics
change tooth shape/colour
correct peg shaped laterals incisors
reduce/close spaces
align labial surfaces of instanding teeth
minimal tooth prep
disadvantages of veneers
often fail and require replacement with crowns
destructive prep
irrevsible
expensive
indications for veneers
sound tooth - perio
mild discolouration
hypoplasia
fracture tooth
tooth wear
shape modification/space closure wanted
contraindication veneers
poor OH
heavily restored/extensive tooth surface loss - insufficient bonding area
high caries rate - interpoximal caries
gingival recession/ root exposure
heavy occlusal anterior tooth contacts
severe discolouration
2 types of veneer materials
composite and porcelain
adv composite veneer
less destructive
can be direct or indirect
adv of porcelain veneers
better aesthetics and stronger
but indirect only, cost more
standard tooth prep for veneers
0.5mm incisal depth cuts - for labial reduction
chamfer finish line extending to gingival margin and into embrasures (short of contact point)
incisal edge reduction (0.5mm)
indications for crowns
protect weakened tooth structure - cuspal coverage
restore function
fixed bridge retainer
after veneer failure
contraindications for crowns
active caries/perio disease
lack of tooth tissue available - ferrule
unfavourable occlusion
healthy tooth
poor OH
advantages of crowns
restore function
strong
good aesthetics
abutment possible - restore tooth shape
disadv of crown
destructive to tooth
£££
irreversible
indirect - multiple visits
likely to fail and need post/core
principles of crown prep
preserve tooth structure
retention and resistance form
structural durability
marginal integrity
preserve periodontium
aesthetic considerations
materials for crowns
precious metal - gold shell crown
Porcelain jacket crown
metal ceramic crowns
all ceramic crowns - zironia, lithium disilicate
non precious metal - stainless steel
metal crown margins
0.5mm axial, non-working cusp;
1.5mm functional cusp;
0.5mm chamfer
PJC prep
1.0mm axial, non-functional cusp;
1.5mm functional cusp;
1.0mm shoulder
MCC prep
- 1.5mm axial, non-working cusp;
- 1mm functional cusp;
- 0.5mm lingual chamfer, 1.5mm buccal shoulder (0.4mm metal and 0.9mm porcelain)
ceramic crown prep
1.5mm axial, non-functional cusp;
2.0mm functional cusp;
1.5mm chamfer circumferentially
functions of temporaries
restore function
restore aesthetics
restore occlusion
prevent sensitivity
prevent microleakage
prevent bacterial ingress
characteristic ideal temp restoration material
non irritatnt
good aesthetics
good strength
good wear resistant
dimensionally stable
able to be removed
labial margin
shoulder
palatal margin
chamfer
3 example preformed provisionals materials
metal
plastic
polycarbonate
easier to use, unlikely to fit accurate
stages in making custom made temporary
pre-prep impression
prep
fill impression with temporary cement
re-seat impression
cure
remove impression
trim temp
check occlusion
3 options for RCTx anterior tooth with margin ridges
composite
veneer
crown
+/-bleaching
options for RCTx anterior tooth without marginal ridges
core and crown
post-core crown
posterior RCTx tooth options
onlay
crown
core build up + crown
defintion of core
provides retention for crown in a tooth with insufficient tooth tissue remaining
core material options
composite - good aesthetics; strength; bond; technique sensitive
amalgam - strong; not retentive; poor; aesthetics
GIC - temp only - moisture ingress
ferrule definition
collar of dentine circumferentially for crown placement
min 1.5-2mm
min 1-2 vertical axial tooth structure within crown structure
prevents fracture
post definition
provides retention for core in teeth with insufficient tooth structure remaining
in canal with 4-5mm apical GP remaining, at least 50% of length into root, ideally 1:1 post:crown length ratio, 1/3 root width
longest straightest canal
post materials
Cast metal/SS - poor aesthetics, radiopaque, root # common, corrosion.
Most common - Ceramics - high flex strength and # toughness, good aesthetics, difficult retrievability, root # common
Fibre - flexible, good aesthetics, retrievable, bonds to dentine (DBA), radiolucent, similar properties to dentine. Requires 2mm ferrule
ideal post features
3
parallel sided
non threaded (passive)
cement retained
define bridge
prosthesis used to replace missing teeth and attched to one/more natural teeth
indications for bridge
7
restore function
prevent unwated tooth movements (space maintainer)
restore aesthetics
cooperative pt - OH
systemic disease - implants contraindicated
improve distibution of occlusal load
heavily resotred dentition
contraindications for bridges
7
Poor cooperation,
poor OH - high caries rate and active unstable perio disease,
further tooth loss within arch likely,
poor abutment prognosis,
span length too great,
bone loss (mobility),
tilted/rotated teeth
advantages to bridges
4
Restore function,
restore stability - improve distribution of occlusal load
restore aesthetics,
fixed appliance
fill gaps
disadvantages of bridges
4
Destructive prep,
generally expensive,
risk of debond (caries, etc.),
if teeth not stable or high occlusal load - may rotate
metal shine through
3 types of bridges
adhesive or conventional - cantilever or fixed-fixed
fixed - moveable bridge
spring cantilever
4 key considerations of pontic design
Cleansability,
appearance,
strength,
surfaces
Pontic types
5
Wash-through (hygienic/sanitary) - no contact, not aesthetic
Dome-shaped - point contact with tip of ridge
Ridge lap/saddle - difficult to clean
Ovate - greatest mucosal coverage, difficult to clean
Modified ridge lap - minimal buccal ridge contact, lingual cut away. Good aesthetics, most popular, risk of food packing
reasons for bridge failure
3 categories
loss of retention (debond)
mechanical failure (fracture of casting),
abutment teeth problems (secondary caries, loss of vitality, perio disease)
5year and 10year success rate for RBB
Adhesive - 80% 5/10yrs
highest rate of failure in initial 2 years
5year nad 10year success rate for conventional
93%, 89%Cantilever
91%, 80% fixed
Implant-retained - 95%, 87%
abutment
tooth used as a bridge attachment
pontic
arrtifical tooth suspended from abutment teeth, repalces missing tooth
retainer
extra coronal restorations connected to pontic and cemebted to abutment teeth
connector
connect pontic to retainer
edentulous span
space between natural teeth to be filled
saddle
area of edentulous span over which Pontic will lie
pier
abutment tooth which stands between and supports 2 pontics (each pontic attached to further abutment tooth)
unit
abutment or pontic
support
resistance to occlusal load/occlusally direct displacement
resistance
prevents dislodgement of restoration by forces directed in apical/oblique direction and prevents movement under occlusal forces
retention
prevents removal of restoration along PoI or long axis of abutment
describe fixed-fixed bridge
Rigid connector at either end of edentulous span.
descrive fixed-moveable bridge
Pontic anchored rigidly to major retainer at one end and via moveable joint to minor connector at other end.
disadv fixed-moveable bridge
2
complicated lab construction, limited by span length
adv fixed-moveable bridge
3
No PoI required,
conservative prep,
allows for minor tooth movement,
adv fixed fixed bridge
3
Robust, good retention, good strength,
disadv fixed fixed bridge
2
difficult prep, destructive prep
describe cantilever RBB(adhesive)
Resin retained by wing (usually metal CoCr 0.7mm; can be ceramic)
by 1 pontic
toothwear definition
Irreversible loss of tooth substance by factors other than caries or trauma
attrition
wear caused by tooth-tooth contact
abrasion
wear casued by abnormal mechanical processess independent of occlusion
e.g. toothbrushing, wire stripping, pipe smoking etc
erosion
pathological loss of tooth substance by chemical process not involving bacteria
abfraction
pathological loss of hard tissue from eccentric occlusal forces leading to compressive and tensile stresses at cervical fulcrum of the tooth
clinical features of attrition
polished wear facets,
reduced crown height,
matching wear facets on opposing teeth
clincial features of abrasion
V-shaped/rounded lesions (usually cervical),
sharp enamel margin
clinical features of erosion
occlusal cupping,
exposed dentine,
smooth surface, loss of surface detail,
restorations stand proud,
reduced crown height
irregular occlusal plane, non-uniform loss,
no chalky appearance or staining
labial/buccal if extrinsic acid, palatal/lingual if intrinsic,
toothwear indices
3
BeWe, Smith and Knight, Eccles and Jenkins
BEWE index
british erosive wear examination
0 no surface loss
1 initial loss of surface texture
2 distinct defect, hard tissue loss <50% of surface area
3 distinct defect, hard tissue loss >50% of surface area
consequences of untreated erosion
5
Pain,
sensitivity,
loss of OVD,
poor aesthetics,
loss of vitality
extrinsic sources of acid
fruit (juice), iron, vitamin C, vinegar, carbonated drinks, some alcohol e.g. white wine
intrinsic sources of acid
GORD, vomiting, eating disorders, pregnancy, stress, rumination
tx options for erosion
Identify and remove cause,
prevention (OHI, FV), diet advice,
desensitising agents,
composite build-ups,
indirect restorations - veneers, crowns, onlays
crown lengthening
tx for attrition
Identify and remove cause,
behaviour management - stress management, habits
hard/soft splint,
composite build-ups,
indirect restorations,
crown lengthening
tx for abrasion
Identify and treat cause,
behaviour Mx,
OHI,
lifestyle/habit change,
composite build-ups,
indirect restorations,
crown lengthening
2 types of desensising agents
Strontium chloride/NaF/stannous fluoride -
Potassium nitrate
strontium chloride/NaF/stannus fluoride mech of action
occludes dentinal tubules, narrowing opening, less affected by air and hydrodynamic theory
potassium nitrate mechanism of action
interacts with AP propagation, preventing APs firing as efficiently, reducing sensitivity
3 techniques for composites build ups
Putty matrix,
vacuum-formed stent
free hand
adv of composite build ups
7
Good patient satisfaction,
seldom TMJ problems,
no detrimental effect on pulp,
no perio disease worsening,
easy to repair,
no LA,
no drilling
disadv of composite build ups
4
Short/medium-term solution,
requires repair and maintenance,
good aesthetics but not excellent,
unrealistic patient expectations
how to tx localised ant toothwear with space
Composite build-ups, lowers before upper
how to tx localised posterior toothwear
Asymptomatic - prevention, monitoring
Occlusal wear - fill in defects with composite (ensure canine guidance)
how to tx generalised toothwear with loss of OVD
Dentures then composite build-ups
how to localised anterior tooth wear with no space
DAHL technique
DAHL technqiue
Method of creating interocclusal space where no existing space for restoration placement in cases of localised wear
describe DAHL technqiue
Composite build-ups to anteriors (incisor and canine contacts only),
posterior disclusion, 2-3mm OVD increase,
3-6mths to create inter-incisal space - anteriors intrude and posteriors erupt causing posterior occlusion and inter-incisal space when composite removed
indications for DAHL technqieu
yonger pts
localised wear with loss in OVD
contraindications ot DAHL technqieu
Bisphosphonates use,
active perio disease,
TMJ problems,
post-ortho,
implants,
existing conventional bridges,
ankylosed teeth
adv to DAHL technqieu
No prep/LA, relatively simple and atraumatic
disadv of DAHL technique
Long treatment course, likely to require to be replaced over time
extrinsic sources of staining
smoking, tannins, chromogenic bacteria, CHX, iron supplements
intrinsic sources of staining
fluorosis, amalgam, tetracycline, ageing, porphyria, cystic fibrosis
tx options for discoloured teeth
4
HPT,
micro-abrasion,
external vital bleaching,
internal non-vital bleaching
veneers - direcr or indirect
contituents of bleaching gel
Carbamine peroxide,
carbapol,
urea,
surfactant,
potassium nitrate,
fluoride,
pigment dispersers,
preservatives,
flavourings
active ingredient in bleaching gel
carbmamide peroxide
how does carbamide peroxide work
breaks down to form hydrogen peroxide and urea.
Hydrogen peroxide breaks down to form water and oxygen and forms free radical - hydroxyl
max concentration of carbamide peroxide
16.7% (6% H2O2)
risks of whitening
9
sensitivity,
wears off/relapse,
allergy,
does not affect restoration colour,
gingival irritation,
cytotoxicity/mutagenicity,
tooth damage,
might not work,
reduced compliance leads to a reduced effect
predictors of sensitivity after whitening
5
Pre-exisiting sensitivity,
high concentration of bleaching agent,
frequency of technique change,
bleaching method,
gingival recession
describe how discolouration occurs
and how external vital bleachin works
Discolouration occurs due to the formation of chemically stable, chromogenic products within the tooth substance.
Whitening causes oxidation through H2O2.
Oxudation leads to the formation of smaller molecules which are often not pigmented and can cause ionic exchange in metallic molecules, leading to a lighter colour
indications for external vital bleaching
Age-related darkening,
mild fluorosis,
post-smoking cessation,
tetracycline staining
methods of external vital bleaching
2
Chairside - HPT, dam, bleaching gel applied, heat/light applied, tooth washed, dried, repeated
Home - dentist for HPT, impressions, tray fitting. Trays have 1mm buccal spacer. Patient brushes teeth, loads spacer with bleaching gel, seats tray for 2hrs (usually overnight). Trays should stop 1mm short of gingival margin
adv of chairside external vital bleaching
ontrolled by dentist,
quick results for patients, can use heat/light
adv of home external vital bleaching
asy and quick to do, good results, relatively cheap
indications for inernal non vital bleaching
3
Non-vital tooth, adequate RCT, no Periapical pathology
2 contraindications for internal non vital bleaching
Heavily restored teeth,
amalgam staining
adv of internal non vital bleaching
Easy,
conservative,
good patient satisfaction
disadv of internal non vital bleaching
Doesn’t always work,
external cervical resorption
procedures for internal non vital bleaching
HPT, dam, remove filling,
remove GP to 2mm below ACJ, RMGIC over GP to seal canal,
dark dentine removed, etch internal surface, place gel,
cotton wool roll, GIC temp.
Repeat weekly for 3-4 weeks then place white GP in pulp chamber and lighter composite shade
external cervical resorption in internal nonvital bleacing
what it is and why
prevention
Occurs due to diffusion of H2O2 through dentine into perio tissues.
More likely if higher concentration and heat.
Prevent by placing RMGIC over GP to seal canal
combination bleaching
internal bleaching as normal but no temp restoration.
Bleaching tray with palatal reservoir. Gel in cavity and tray and replaced regularly
microabrasion
Removal of discolouration limited to outer layer(s) of enamel.
Controlled acid erosion and pumice abrasion
indications for microabrasion
Mild fluorosis,
post-ortho demin,
demin with staining,
before veneering if dark staining present
contraidindications for microabrasion
Eroded teeth,
tetracycline/amalgam staining,
primary teeth
adv of microabrasion
Quick,
easy,
no LT problems
disadv of microabrasion
Sensitivity,
yellowing dentine shine through,
can only have one course,
only works for superficial staining
techniques for microabrasion
HPT, dam, sealant. 18% HCl mixed with pumice, applied to teeth. For 5s x10 or 10s x5. Teeth rinsed/washed, dam removed, fluoride prophy polish, FV. Avoid coloured foods for 7 days post-R
factors to consider before implants
systemic medical history - bisphophonates, immunosuppression, poorly controlled diabetes, scleroderma
Smoking status,
bone quality, bone quantity,
OH - caries rate, poor perio status
patient motivation,
occlusion,
aesthetics
bone dimesntions needed for implants
best way to mesaure this
1.5mm horizontal bone around impact,
3mm between implants,
>5mm space for papilla between bone crest and contact point,
7mm height of bone,
at least 2mm from important structures (IAN, sinus, etc.)
CBCT
alt to implants
do nothing and accpet gap
RPD
bridge
possible grafts
Autograft - own tissue
allograft - diff human tissue
xenograft - diff species tissue
allopastic - artficial tissue
implnat av intergation time
Mandible - 3mths
Maxilla - 4-6mths
