Clinical Dental Sciences Flashcards
What shape of cavity is required for an amalgam restoration and why?
a large cavity that tappers out at the ends, amalgam doesnt bind to the tooth, requires mechanical strength to hold it in place
what shape of cavity is required for a composite resin restoration and why?
A smaller cavity, starts wide and tappers in at the bottom, the composite binds to the tooth so less mechanical strength required
Describe the acid etch technique
once cavity prepared, phosphoric acid is put on to the surface, a bond is then put on, composite resin is then used to fill the cavity, by binding to the bond
what is creep
when small, low level forces build up over time (eg biting), cause the amalgam to rise above the tooth surface, which can then be fractured
why is the thermal expansion of materials important
ideally want the same thermal expansion as the tooth, after exposure to cold, if the tooth and material expand at different rates, there will be a gap between allowing for microleakage, can result in secondary caries
how can impression materials differ
in viscosity
when are more viscous impression materials used
initially, to gain an overall impression, less likely to be distorted due to its rigidity
when are less viscous impression materials used
too gain more accuracy, can be put around specific areas and then the initial tray inserted to produce one impression with both materials
why do impression materials need to be elastic
for removing from the mouth, needs to be able to retain shape after
what must be considered when selecting a tray for impression taking
extend past the last standing tooth
cover all the sulci
not be in contact with buccal or lingual surfaces
how are impression trays disinfected
rinse under the cold tap, place in bath with disinfectant for 10 minutes, rinse under cold tap, place gauze on impression and place into a sealed bag
what is a high speed handpiece used for
removing carious enamel and preparing the cavity
why is water used with the high speed handpiece
due to the amount of heat produced, this cools it down
what burs are used with high speed handpiece
diamond shaped round or fissure bur - preparing and extending cavity
what is the slow speed handpiece used for
for increasing the depth of cavity, being careful not to extend into non-carious dentine
what bur is used with the slow speed handpiece
round bur
what is intercuspal position
when the mandibular teeth are maximally braced with the maxilla
what is the position of teeth relative to the opposing arch in ICP
mandibular buccal cusps lie in fossae of maxillary teeth, maxillary palatal cusps lie in fossae of mandibular teeth, lower incisal edge in contact with cingulum of upper
how is shimstock used
10 micrometers thick, when in ICP shouldnt be able to move the paper, if mobile, occlusion imbalanced
how is articulating paper used
40 micrometers thick, placed between teeth and ask patient to repeatedly bite down, should leave ink on the areas of contact, check all teeth are in contact and there is not one tooth under more pressure than others
how is stability of occlusion maintained
by opposing teeth or adjacent teeth - prevents over-eruption
what is the movement of the non-working side in eating
downwards, forwards inwards
what is the movement of the working side in eating
lateral movement
name 3 types of tooth wear and what is associated with each
erosion - cupping
attrition - loss of tooth height
abrasion - toothbrush
what should be checked in an extra-oral exam
facial asymmetry, lymph nodes and temporomandibular joint
what lymph nodes are checked in an extra oral exam
sub-mental, sub-mandibular, buccal/facial, pre-auricular, post-auricular, occipital and cervical chain down neck
what is checked in TMJ
muscle function and bulk, opening and closing jaw and listening for any clicking
what surfaces are checked in an intra oral exam
lips, lingal, palatal, buccal, dorsum and ventral tongue
what should be looked out for in an intra oral exam
any irregularities, angular chelitis, fungal infections, if the mirror is sticking to the mucosa may have dry mouth, the mucosa should be pink and shiny, any cancers
what are the steps for hand hygiene
palm to palm, backs of hands, fingers interlaced, backs of fingers, finger tips, thumbs and wrists
what are the 5 points that hand hygiene is required
before touching patient, before procedure, after exposure of body fluids, after touching patient, after touching patients surroundings
what order is PPE put on
hand hygiene, apron, face mask, visor, gloves
what order is PPE taken off
gloves, apron, visor, face mask
what bin is PPE put in
clinical waste
how are sharps disposed of
in sharps box
what is done with infected instruments
put in red box, check list to check what is there, put in with tag and taken to CSSD
what order is the unit decontaminated
start at top, at light and handles, then head rest, back of chair and handles, then the bracket table, cables, the aspirator and cables, spittoon done last and check for contamination on units
when are bitewings used
for carious diagnosis, need to ensure no overlap of adjacent teeth or caries may be hidden
when are periapical radiographs used
to check alveolar bone levels, zoom in to apex and root to check for inflammation
when are occlusal radiographs used
to check for supernumary teeth
when are panoramic radiographs used
to check the whole dentition, can check for overcrowding
on the clock face, what area is the transfer area
4-7
on the clock face, what area is the nurse zone
2-4
on the clock face, what area is the operating zone
7-11
on the clock face, what area is the static area
11-2
