Restorative 2 Flashcards
what is an impression?
negative imprint of an oral structure used to make a positive replica
what are the components of alginate?
irriversible hydrocolloid carbonated polysaccharide based on alginic acid - gels by cross linking of calcium ions sodium alginate calcium phopshate sodium phosphate - retarder fillers - zinc carbonate pH indicators
what is the working time of alginate?
gelation ideal time of 3-4 mins
spatulation of 1 min
working time - 30 secs
what should an impression tray cover?
retromolar area of mandible
maxillary tuberosity
anterior - clears most protruded incisor
how do you seat a lower impression?
pt should lift tongue
how do you seat an upper impression?
seat post before ant
how do you disinfect an impression?
sodium hypochlorite 5-10 mins
10- tabs/litre for 2 mins
what is a wax bite?
interocclusal record
registration of normal positional relationship of arches
what is gate control theory?>
melzack and wall 1965
pain is modulated at the spinal cord and influenced by physiological and psychological and socoiocultural factors
what is the adults pain index?
childrens?
mcgill
wong and baker
what are other forms of pain and anxiety control?
hypnosis
acupuncture
electric analegsia
what is the aim of analgesia?
elimination of pain
haemostasis
how is haemostasis achieved by anaesthetic?
vasoconstrictor
tissue blanching - local ischaemia, prolonged activity, reduced toxicity
how do the nodes of the ranvier take part in anaesthesia?
ionic exchange of pain impulses
analgesic solution gains access here and blocks nerve conduction
what causes pain?
inflammation trauma necrosis ischaemia K, Na, Cl, Ca
what are the stages of polarisation?
1 - polarisation - no pain, potassium in cytoplasm, na outside
2 - depolarisation - ionic exchange, destruction of polarity, sodium outside
3 - action potential - change in membrane potential permeability, transference of ions
4 - repolarisation - sodium potassium pump, reverts ion to polarised state
what are the contents of LA?
vasoconstrictor - prolongs anaesthetic time
reducing agent - prevents oxidation of vasoconstrictor, competes with adrenaline for oxygen
preservative - poss allergic reaction
fungicide - thymol
carrier solution - modified ringers lactate solution adjusted for biocompatible pH
what is lidocaine?
dissolved in solution as HCL salt
2% solution
what is prilocaine?
3% octapressin
4% plain
less effective at haemorrhage control but only slightly vasoconstrictive
what is mepivicaine?
2% 1:100000 ep
3% plain
what is articaine?
more quickly metabolised good for repeat injections with ep
what does epinephrine give?
more profound anaesthesia, longer lasting
what to be careful with giving LA to someone with liver disease?
risk of toxicity
bc impaired metabolism
what to be careful with giving someone with cardiac disease?
impact on epinephrine use
arrhythmias/unstable angina
what is the max dose of plain lidocaine?
2%
11 cartidges/70kg adult
6-8/70kg
what is the max dose of plain prilocaine?
with octapressin?
9/70kg
4
what may the analgesic component of LA interact with?
beta blockers
calcium channel blockers
what may the vasoconstrictor component of LA interact with?
beta blockers diuretics calcium channel blockers antiparkinson drugs canabis
what are contraindications to LA?
leukaemia, antcoag therapy, steroid therapy, liver dysfunction, renal disease, local sepsis/vascular abnormality
pregnancy, rheumatic fever, uncontrolled diabetes, toxaemia, haemophilia
what are local complications to LA?
infection IV infection haematoma nerve damage needle fracture cartidge failure facial palsy needle stick
what are the divs of the trigeminal nerve?
opthalmic nerve
maxillary
mandibular
what are the main divisions of the maxillary nerve?
superior alveolar nerve
nasopalatine
greater palatine
what are the main divisions of the of the mandibular nerve?
inferior alveolar nerve incisive nerve mental nerve long buccal nerve lingual nerve
what is the superior alveolar nerve?
sensory branch of the mandibular nerve
foramen ovale - infratemporal fossa
passes through lateral and medial pterygoids
through mandibular foramen into mandibular canal
where is an IDB placed?
analgesia introduced to nerve through lateral side of mouth into fat of pterygomandibuar space
what are contra indications to an IDB?
haemophiliacs
anticoagulant tx
co operation
what is the aim of an IDB?
to deposit the solution as close to the mandibuar foramen as poss
what is the anatomy associate with an IDB?
external oblique ridge at anterior aspect of ascending ramus
pterygomandibular raphe
thumb palpates ramus
needle from premolars of opp side
barrel of syringe parallel to lower occluasal plane
above occlusal level of last standing molar
what is the nerve supply to the maxillary incisors and canines?
superior alveolar nerve
palatal - nasopalatine
what is the nerve supply to the maxillary premolars?
mid sup/plexus
palatal - gretater paltine/nasopalatine
what is the nerve supply to the max molars?
superior post alv nerve
palatal greater palatine nerve
how can the zygomatic arch cause problems with LA>
mesial and distal LA
how do you aneasthetise the lingual nerve?
interpapillary
LIA under lingual attached gingivae
why do teeth need restored?
restore tooth integrity
restore function
remove disease
restore appearance
what is the tx of a proximal enamel lesion?
monitor
duraphat
what is the tx of a proximal enamel lesion at ADJ?
high risk - restore
low risk - monitor
what is the tx of a proximal dentinal lesion in outer third of dentine? mid third of dentine?
outer third - high risk - restore
low - monitor
mid - restore
what is microprep?
burs and handpieces of reduced size used with magnification
what is chemo mech caries removal?
sodium hypochlorite 0.5% carisolv
what is sonic prep?
vibration rather than rotary movements
what is air abrasion?
aluminium oxide through a nozzle
what are lasers used for?
soft and hard tissue removal
what is ozone?
caries identified with a laser
acitve oxygen to anaerobic bacteria
what is ART?
hand excavation and GI
what is blacks classification?
1 - occlusal surfaces of molars and premolars and buccal pits of molars
2 - approximal surfaces of molars and premolars
3 - approximal surfaces of incisors and canines
4 - inicisal edges of incisors and canines
5 - cervical margins
what is wrong with blacks classification?
pre adhesive materials
removes too much tooth tissue
does not include secondary or root surface caries
what are the stages of a filling?
outline form resistance form retention form tx of residual caries correction of enamel margins cavity debridement
what is outline form?
gaining access to caries
- direct access/cutting through enamel
what is resistance form?
resisiting occlusal forces
cavity floor at right angle to direction of occlusal forces
ensure sufficient depth
what is retention form?
retaining material in cavity
grooves/undercuts/occlusal keys/bond
how do you treat residual caries?
1st ADJ.2nd base of cavity
firm stained dentine can be left in cavity base
why do you correct the enamel margins?
leave no unsupported margins
bevel surface to increase bonding area
what are names of the walls/floors of the cavity?
occlusal floor
pulpoaxial wall
gingival floor
what is a line angle?
where 2 lines meet
what is a cavosurface angle?
where the cavity wall meets the tooth surface at an angle of 90 to 110 degrees
what is a point angle?
3 or more lines
what is a fissure sealant?
hard insoluble material in liquid form used to fill pits and fissures without cutting enamel
what is the aim of using FS?
eradicate fissures
aid cleaning
prevent caries
what is acid etch and what does it do?
30-50% phosphoric acid
dissolves enamel - up to 8 micrometers of enamel
porosities up to 50micrometres deep
what are they etching patterns?
1 - core removed, periphery left = most common
2 - core intact, peripheries removed
3 - haphazard effect - not related to prism morphology
what are the diff types of set fissure sealants?
self polymerised
UV light cure
white light polymerised
what can fissure sealants be filled with? what does this do?
lithium alumina silicate
increased abrasion resistance
increased wear of opposing teeth
when to use FS?
high caries risk medically compromised limited dexterity tooth cant be isolated deep fissure pattern
what are occult caries?
occlusal surface intact but carious underneath - bacteria enter deepest part of fissure and rapidly spread along ACJ
when do you restore caries?
obv cavitation
caries at EDJ
infected dentine
what is a PRR?
restore carious part of fissure system and seal over rest
what is the c factor?
number of bonded surfaces over the number of unbonded surfaces
what class cavities are approximal cavities?
anterior - class 3 posterior - class 2
how do class 2 cavities develop? how are they diagnosed?
below contact point
visual
bitewings
transillumination
what is the use of a matrix band?
retain material in cavity
restore contact points
protection of adj tooth during cavity prep
what is a tunnel prep?
gaining access to caries from occlusal and leaving marginal ridge intact
what are cervical caries a sign of?
high risk pt
what is the tx of cervical caries?
ensure cavity is self cleansing
intervene when pulp is threatened
what are problems with restoring cervical cavities?
access
moisture control - blood/gcf
contouring
what are risk factors for RSC?
xerostomia diet partial denture wearing poor oh high caries experience salivary s mutans count
what is physiological tooth wear?
pathological tooth wear?
occurs with age
excessive toothwear
what is attrition?
loss of tooth substance as a result of mastication or of occlusal/proximal contact between the teeth
what is physiological attrition?
occlusal surfaces/incisal edges
prox surfaces because of mastication
deciduous more susceptible
-
what are signs of physiological attrition?
disappearance of mammelons
occlusal cusps flatten
exposed dentine - brown cup shaped lesions
what is pathological attrition?
confined to local areas, parafunction or misalignment
e.g - bruxism/clenching/grinding
what are signs of pathological attrition?
visible wear facets abnormal attrition rate hypertrophy of masticatory muscles TMJ pain tooth mobility sensitive to cold
what is abrasion?
pathological wearing away of tooth structure because of repetitive mechanical habit - notches in root surface
why are pulpal exposures commonly avoided in NCTSl?
slow process - secondary dentine laid down
what are the types of abrasion and what are they caused by?
1 cervical abrasion - v shape - horizontal brushing
2 habitual abrasion
3 iatrogenic - grinding to accomodate filling
4 industrial abrasion
what is abfraction?
tooth flexure from occlusal loading
microfractures in enamel
cavitiation
what is erosion?
progressive loss of tooth structure by an acidic chemical process without bacterial involvement
what are signs of erosion?
smooth polished surface shallow depressions proud restorations palatal/incisal chipping of edges cupping of molar cusps
where does extrinsic erosion affect the teeth?
labial surfaces of ant teeth
occlusal surfaces of lower molars
where does intrinsic erosion affect the teeth?
palatal surfaces of uppers
occlusal surfaces of lower perm molars
what are sources of intrinsic erosion?
hiatus hernia alcohol abuse bullimia pregnancy gastric ulceration reflux
what does the pulp need protection from?
- chem attack - acrylic resin/acids in dentine, bonding agents and residual acid from acidogenic bacteria
- thermal attack - polymerisation exothermic setting reactions, hot/cold food and drink, cavity prep
- galvanic shock - restorations of disimilar material in close proximity set up an electrolyte cell = pain
how does cavity prep insult the pulp?
increased inflammatory cell infiltrate
smear layer produced = occludes tubules with bacteria from cavity, collagen and HA
describe calcium hydroxide?
high pH - bacteriocidal
high pH - initially irritant - reactionary dentine produced
insulator, radiopaque, compatible, strong
no coronal seal
describe zinc polycarboxylate?
high MW = reduced tubule penetration, mild irritation
F = bacteriostatic
strong,, insulates, compatible, radiopaque
describe zinc eugenol?
slight irritancy bacteriocidal and radiopaque bc zinc content insulates not compatible, no coronal seal v obtundant
describe zinc phosphate?
low pH. low MW = highly irritant
insulator, bacteriocidal, radiopaque, compatible, strong
not obtundant, no seal
desrcibe glass polyalkenoates?
low pH high MW = mild irritancy
F = bacteriostatic
insulates, strong, direct adhesive, good seal
compatible
when to line a cavity?
<2mm no lining
>2mm line
line pulpal wall and occlusal floor
when would you feel discomfort from a tooth?
when caries is within 0.5mm of pulp
what is an indirect pulp cap?
cavity in 0.5mm of pulp
caoh and GI
what is a direct pulp cap?
exposed pulp
vital tooth, no history of pathology, no periradicular pathology, pulp pink and healthy, no excessive bleeding,
caoh and GI
what is a stepwise excavation?
stained soft dentine is left in the base of a cavity but a cleared ADJ seal over base with dycal dress with GI cement remove 6-12 months = stained but firm base of cavity
what is the restorative staircase?
with each restoration = larger prep and prep eases gradually towards pulp
when can a restoration be repaired or refurbished?
aesthetics
no pain
no caries
