Restorative Flashcards
Tooth 11 has a traumatic exposure. What 2 factors would influence your choice of treatment?
size of exposure
time since exposure
How would you treat traumatic pulpal exposure in practice?
partial or complete pulpotomy
partial- removing 1-3mm of affected pulpal tissue whilst complete is removing full height of coronal pulpal tissue
la -> dam + isolation -> access with hi speed round bur -> remove 2-3mm with bur -> saline irrigation ->
ferric sulfate for haemostasis ->apply hard setting CaOH dressing
need to assess bleeding- if abnormal bleeding- may need to pulpectomy
indicted in: vital traumatically exposed young permanent tooth- espec with incomplete apex.
If restoring deep carious lesion and radiographically you are concerned about extent near pulp how do you procede
indirect pulp cap may be placed.
• Caries should be carefully removed in a progressive manner to reduce pulpal exposure w slowly rotating contra-angle handpiece or sharp hand excavators.
- The cavity should be cleansed with 0.2% w/w chlorhexidine gluconate.
- Stained (not soft) dentine over the pulp should be left in situ and covered with a setting calcium hydroxide cement, for example Dycal
- A stronger lining material (Resin-Modified Glass Ionomer cement - Vitrebond) should then be placed to protect the Ca(OH)2 and the tooth restored with a provisional restoration, for example GIC or RMGI.
- The tooth must be vital, asymptomatic and have no history of previous pulpitis.
- The tooth should be monitored for 3 months and if vital and asymptomatic, the provisional restoration should be removed, stained dentine carefully excavated and definitive restoration placed.
- If there have been any pulpitic symptoms, then RCT should be undertaken.
direct pulp capping restricted to:
teeth with a good prognosis, young patients in good health, lack of pre-existing symptoms, fresh non-carious exposure and minor pulpal haemorrhage.
indications for ledermix use
Ledermix paste or cement (antibiotic/steroid mixture) should not be used as a pulp capping agent. The only indication for the use of Ledermix is as a temporary palliative agent in contact with vital (possibly inflamed) pulp either in a pulp chamber or root canal, when it is intended that the tooth should be extracted or root canal treated
how to carry out first stage of endo- canal preparation
- consent gained. pt to wear bib and glasses
- pre-op radiograph PA grade 1 w/in 3 months of commencing
- assessment of tooth- must be caries free and restorable. perhaps pre-endo build up to allow for dam placement and reduce change of leakage
- LA administered
- dental dam placement. if isolation cannot be achieved XLA indicated. as early as poss. if elected to cut access cavity prior to dam placement all dam equipment should be prepped for immediate placement prior to or as soon as pulp exposed
- Disinfect access opening, clamp and dam with CHX
- Using a diamond bur in the high speed handpiece with water spray and wide bore aspiration, cut the initial outline form of the access opening into dentine.
- Using either a high-speed fissure bur or preferably the slow speed handpiece with a long shank/neck round bur make an opening into the pulp chamber
9.Using a high speed safe tipped endodontic access bur (e.g. Endo Z bur) or slow speed round bur, remove the remainder of the roof of the pulp chamber. do not allow bur to touch pulp chamber floor - Remove contents of the pulp chamber with a discoid excavator.
- Remove any remaining overhanging edges of the pulp chamber roof so that the walls of the access opening are smooth using the safe-tipped endodontic access bur.
- check integrity of dam seal prior to irrigation. opaldam used if necessary
- NaOCl irrigation
- 17% EDTA irrigation as penultimate irrigation- 1 min soak
- establish glide path,
- Once the EWL has been reached with a size 10k file an electronic apex locator should be used to determine proximity to the apical constriction / apical patency. repeated at least three times
- working length radiograph taken and correct working length established.
- coronal flare established with gates glidden (largest to smallest)
- working length radiograph taken and correct working length established.
- Root canal instrumentation
- 10 min NaOCl soak
- Manual irrigation with GP point after final instrumentation
- if finished in one- obturate and post of radiograph before definitive restoration & monitor
if not finished in one appt- non setting CaOH2 (ultracal) placed in root canals, with cotton wool above and GIC above that as temp rest.
if vital pulp remains and anaesthesia difficult to achieve- odontopaste (zoe)
pulpotomy?
removal of portion of diseased pulp in hope to maintaining the vitality of the remaining portion through placement of a therapeutic dressing
factors needed discussed for consent?
procedure
prognosis
risk
alternatives
risks of endo?
post op pain post op swelling instrument fracture material extrusion failure to negotiate to working length perforation root fracture hypochlorite accident need for pain management
dam placement tips?
For posterior teeth punch largest single hole 2 cm diagonally from the centre of the dental dam sheet and turn to appropriate quadrant. For anterior teeth the hole may be punched more peripherally, to ensure the dam does not cover the patient’s nose. When the patient’s mouth is open, the top lip should be covered by the rubber dam.For multiple tooth isolation the rubber sheet can be held against the teeth and points to be punched marked with an indelible pencil.
Suggested clamps : Anteriors “C” or “E” Premolars “E” or EW” Molars “A”, “AW”, “FW” or “K”
measurements taken from pre op radiograph
- length of each root,
- the anatomical reference point
- the estimated working length of each root canal.
- from the anatomical reference point (incisal edge or cusp tip) to the roof of the pulp chamber.
ACJ importance in endo
most reliable anatomic landmark to aid location of canal orifices.
irrigant of choice in endo
2.5-5.25% sodium hypochlorite NaOCl
used in a Luer lock syringe with a gauge 27 Endo needle.
irrigation necessities
label irrigants with adhesive labels 1 min to dispense 3ml syringe never forced under pressure never wedged at end of root canal rubber stopper used to provide length measurement
Aspirate effluent using a plastic disposable saliva ejector with the round tip removed or a Yankauer tip in high volume aspirator, held as close to the access cavity as possible. It is essential that irrigating solutions do not pool around the tooth.
irrigate gently with 17% EDTA solution to remove the smear layer. EDTA should be used as the penultimate irrigant and placed in the canal for one minute.
Final irrigation with Sodium hypochlorite prior to obturation, a 10 minute “soak” is recommended, this can be carried out whilst the dental nurse prepares the equipment and materials required for interappointment dressing or obturation.
Manual dynamic irrigation should be performed following completion of instrumentation. This should be done very gently with a standardized gutta percha point with an apical diameter equal to or smaller than
the master apical file( For example if the master Cone is an F2 ProTaper rotary then a standardised GP cone of apical diameter 0.25mm should be used.)
guidelines for use of NaOCl
- Careful pre-operative radiographic assessment is essential – be vigilant of open apices and perforations and discuss with senior staff if either is suspected prior to commencing treatment.
- It is important that the pre-endodontic restorative state of the tooth is assessed. A pre-endodontic build-up is necessary if isolation is likely to be compromised.
- Ensure the patient is provided with a disposable bib to protect clothing. This must adequately cover clothing. If necessary use two bibs overlapping.
- Provide patient with protective eyewear.
- Always use dental dam to isolate the tooth requiring RCT and ensure this is sealed well with OrasealTM. The oral seal should be “moulded” to the tooth contours with a damp cotton wool pledget. Placing the clamp prior to dam placement can facilitate visualisation. Ensure floss is used to secure the clamp during placement and removed after dam is seated.
- Test the dental dam seal by irrigating with chlorhexidine first to ensure no leakage.
- Dam placement must be checked by the supervising clinician
. 8. Ensure that all syringes are clearly labelled with adhesive labels. - Always use a side-vented needle for irrigation of the root canal.
- Always use a Luer-Lok 27G needle and ensure this is securely attached to a 3mL syringe – test this before use.
- Fill syringe less – approximately 3/4s full to aid control.
- Always use a silicone stop on the needle and set to 2mm short of working length.
- Always pass the endodontic syringe behind the patient’s head and never over the patient’s face.
- The irrigating needle should not bind in the root canal at any time.
- Whilst irrigating, depress the plunger with index finger rather than thumb to reduce the pressure.
- Report any irrigation/endodontic incident to senior staff immediately.
what is a DG16 used for
a DG16 Endodontic probe - used to identifying root canal orifices
. Following developmental root fusion lines can aid in orifice location
difference between EWL and CWL
estimated and calculated
Careful assessment of the working length radiograph along with the apex locator results should allow calculation or the Corrected Working Length
CWL is calculated by adjusting accordingly from if file short or long of radiographic apex. ideally the working length should be approximately 2 mm from the radiographic apex.
CWL = KLI x ALT
/ ALI
known length of instrument x apparent length tooth
/ apparent length instrument
modified double flare technique?
The modified double flare technique allows production of a continuously tapering funnel-shaped preparation. The process involves development of an initial coronal flare, followed by an apical flare. These distinct regions of preparation, upon intersection create a continuous taper. Preparation involves the use of Gate Glidden drills and stainless steel K-files. The K-files are instruments with a 2% taper.
how to carry out obturation
Under dental dam isolation, irrigate the canal thoroughly using NaOCl.
If the root canal filling is being undertaken at a separate visit from canal preparation, wash out all the inter-visit dressing and confirm CWL with a small file and an apex locator, then check that the master apical file still reaches CWL before proceeding to fill the canal.
DO NOT insert the master file immediately or any material in the canal will be compacted at the apex and will block the canal.
Dry the root canal(s) thoroughly using narrow bore aspiration and matched size and measured length of sterile paper points in locking tweezers.
Select “Master” Gutta Percha point – standardized GP point - that will fit canal to the CWL and give the sensation of “tug back”.
Mix root canal sealer (AHPlus).
Using a paper point (coated lightly with sealer) coat the walls of the root canal thinly with sealer
Coat the master point tip lightly with sealer and insert slowly and carefully to WL using sterile locking tweezers. Then:
(a) Gently place a size A or B finger spreader in canal alongside the master point.
The spreader should be left in place for at least 20 seconds to achieve the desired compaction
repeat with more accessory points until firm mass of GP
heat old instrument and use to cut off end of GP mass
condense GP remaining in orifice and remove all obturation material in pulp chamber flush to orifice
WHat factors does a dentist consider when considering implantation?
smoking status bone quality and quantity occlusion aesthetics oral hygiene pt motivation
what bone dimensions are needed for implants and how are they best assessed
assessed via cbct
1.5mm horizontal around implant
3mm between implants
>5mm between bone crest and contact point
3 alternatives for implant in space
1 nothing
2 bridge
3 rpd
how can you check that a bridge has debonded
probe, floss, visually, mobility, push and check for air bubbles
factors needing to be considered before bridge placement
oh
abutment health (perio and caries)
occlusion
length of span
alternatives to a bridge
nothing, rpd, implant, overdenture
signs and symptoms of reversible pulpitis & tx
short sharp pain (aB and ad fibres), pain on cold, no ttp, pain stops when stimulus removed, poorly localised
tx - removal of caries and causative factors, restore
signs and symptoms of irreversible pulpitis & tx
long lasting dull pain (c fibres), pain on hot, spontaneous pain, wakened at night, well localised if reached pdl
tx- rct, xla
how does la work
enters cell, blocks VOLTAGE gated sodium channels and prevents propagation of action potentials
most susceptible to least susceptible to la -nerve fibres
a delta,
C,
a beta,
a alpha
smaller nerves affected quicker (and delta is myelinated .:. affected quicker than c)
name one ester and three amide local anaesthetic
ester- benzocaine
amide- lignocaine, articaine, bupivacaine, prilocaine
(amide or ester bond between hydrophobic aromatic group and hydrophilic amide group)
esters less stable as ester linkage more easily broken
what are the 5 constituents in a la cartridge?
base hydrochloride, vasoconstrictor, fungicide, reducing agent, preservative
max dose of lignocaine
4.4mg/kg
1 cartridge per 10kg
44mg in one cartridge
as
1% = 1mg/100mg = 10ml/L
.:. 2.2mg (cartridge) of 2% lignocaine
2%=2mg/100mg = 20ml/L x 2.2= 44mg/ml
3 ideal post features
parallel
non threaded
cement retained
factors affecting suitability of post
length - 4-5mm GP remaining width - less than 1/3 root width ferrule of 2mm extend below alveolar level post:crown ratio> 1:1
post materials
metal - gold, stainless steel
fibre- glass, quartz
ceramic - zirconia, porcelain
core materials
RMGIC, composite, amalgam
principles of cavity prep
gain access identify extent at adj remove caries remove unsupported enamel resistance and retention form
what is the hybrid layer
prime and bond and conditioner working together make hybrid layer.
is interface between dentine and restorative material
conditioner- etch to expose dentine tubules and remove smear layer
primer- HEMA to support collagen fibrils and make space for bond
adhesive/bond - resin penetrates fibrils and makes resin tags
different types of dentine and how they affect bonding
primary - laid down during development. good to bond to. open tubules
secondary - formed during function. ok to bond to
tertiary- reactionary - mild stimuli or reparative - intense stimuli. poor to bond to - sclerosed or poorly organised tubules
what is the inorganic content percentage in dentine
70% calcium hydroxyapatite
icp?
intercuspal position
the position of best fit
between the maxillary and mandibular teeth. This is therefore
determined by the teeth themselves, not the maxilla and
mandible. There are two forms of ideal contact between two
teeth: cusp to base of fossa and tripod contacts.
guidance
the factors which control movement in the mandible. This includes the forward directions and lateral directions. This guidance can be from the Temporomandibular joint or the teeth themselves
rcp
retruded contact position- also called centric occlusion
reorganised approach?
when the objectives of restorations cannot be achieved in patients current ICP .:. need to use retruded contact position as is reproducible
diagram to show guidance
posselts envelope.
retruded arc - important as is determined by movements of TMJ. .:. is reproducible when occlusion is altered.
the movement is when the condyles are in their most superior position in the articular fossa
crown prep figures for
metal
ceramic
metal ceramic
metal - ceramic - metal ceramic non functional - 1, 1.5, 1.3 functional - 1.5, 2.5, 1.8 shoulder - 0.5, 1, 1.3 chamfer - 0.5, 1, 0.5
crown fit advice to pt
The patients must be advised to floss and ensure the area is as clean as possible – this comes under oral
hygiene instruction. They must also be advised that crowns last on average 8 years but some up to 20. The
most common cause of failure is due to caries so this must also be told to the patient. The patient finally
must also be advised on post-operative sensitivity
veneer prep
4 staged -
incisal prep, buccal prep, interproximal extension and gingival margin
buccal prep-
- 3mm cervically
- 5mm mid buccally
- 7mm incisally
gingival margin-
0.5mm into gingival sulcus no more
incisal prep-
can be feathered, window, incisally bevelled or incisally extended
materials used for inlays and onlays
gold type I and II
composite
ceramic
ceromer (belleglass)
pros cons of gold for inlayonlay
It has a high strength, will cast accurately and will
have a high polish. This means it can prevent plaque accumulation to itself and is suitable for bruxists.
It will not have a natural appearance however, it is expensive, may not retain well and must be cemented in
place, not bonded.
pros and cons composite for inlayonlay
Composite has good aesthetics and when used indirectly it will be very strong (as it can be light cured for
longer). It still will not be as strong as gold however. It will also have less polymerisation shrinkage than
direct composite so there is less microleakage and pain. It is also repairable.
There may however be pooling of bonding materials leading to poor bonding.
pros and cons of ceromers for inlayonlay
Ceromers are aesthetic and also they are more durable than composite. This is due to their increased
fracture toughness and wear resistance. They are also repairable, as with composites. An example of a
Ceromer is Belleglass.
pros and cons of ceramics for inlayonlay
A ceramic inlay or onlay will be aesthetic and will be wear resistant. It also will have a better bond strength
than composite therefore is good for poorly retentive cavities. It can also transmit forces more to the teeth
and there will be less marginal leakage (especially as the fit is better than composite).
All margins must be placed on enamel! Also the wear resistance could be bad as it could wear opposing
teeth! It must also need adequate bulk due to it’s low fracture resistance. This means it may break easily on
try in or if it is too thin.
indications of onlay inlay
heavily restored teeth
repeated fracture of direct restorations
difficult obtaining occlusion
protection of remaining tooth tissue
try in of restorations
This should be done under Local Anaesthetic. The provisional must all be removed, including the cement
and the restoration should have a passive fit without being forced, without undue looseness and without any
blanching of the tissues.
If there is any problems with seating of the restoration, first the proximal area overextension should be
checked. This is because adjustment to this rarely works so the restoration needs to be remade. Then the
fitting surface should be checked. If there is seating failure a sandblasted surface can show up any high
spots. These will be shown as a shiny area. A yellow banded bur can be used to adjust high spots on the
inside only!
Another method to check the fitting surface is to use occlude spray. This is sprayed onto the fitting surface
then the restoration is seated in the mouth. The high spots will have metal showing through. This is very
messy however. Also Fit Checker can be used, this is less messy. It is a condensation cured silicone. It seats
inside the crown and high spots can be shown clearly. It can then be peeled off cleanly.
dahl appliance
used in cases of severe wear where more than 1/3 tooth surface loss.
works by discluding posterior teeth to allow over eruption of the posteriors
usually placed palatally on upper anteriors canine to canine
how to cement post
gi luting cement
comp resin luting cement
how to remove fractured post
ultrasonic Masseran kit Eggler post removal Stiegler forceps Sliding hammer cut out fibre posts
4 reasons for a post-core to debond
iiuc incorrect cementation material inadequate post preparation unfavourable occlusion contamination during cementation
3 reasons why a core would fracture from post
casting errors
inadequate ferrule
trauma
parafunction
3 reasons why a core would fracture from post
casting errors
inadequate ferrule
trauma
parafunction
principles of crown preparation
PRSMPA preserve tooth structure retention and resistance form structural durability marginal integrity preserve periodontium aesthetics
sequence of crown prep
- occlusal reduction
- separation
- buccal reduction
- lingual/palatal reduction
- finishing
factors considered before placing bridge (5)
occlusion, length of span health of abutment teeth oral hygiene perio status
indications for adhesive bridge
missing teeth - usually single
good enamel quality
large abutment surface for bodning
minimal occlusal load
contraindications for adhesive bridge
LPPP long span poor quality enamel parafunction poor perio of abutment
active component of cement for porcelain crown
silane coupling agent- bifunctional molecule in comp resin cement
oxysilane groups hydrolysed to form -OH bonds which then form Si-O-Si with porcelain
organofunctional groups c=c bonds initiated by free radicals to form c-c with comp resin
or Covalent bonds with oxide groups on prcelian surface which is hydrophilic
Hydrophobic C=C reacts with silane in composite resin
how to cement metal crown?
comp resin luting cement
MDP or META form c=oh bonds from c=c
features that could cause failure of conventional bridge
unfavourable occlusion poor crown:root ratio no parallelism poor health of abutment tooth poor oral hygiene- leading to caries
types of bridge
conventional
adhesive
cantilever
fixed moveable
factors to consider before using tooth XX as abutment
occlusal load perio status of XX crown root ratio root morphology root surface area angulation
ante’s law?
root surface area of abutment should be greater than or equal to that of the teeth being replaced with pontics
