Day 1 Lecture 1 Flashcards
Operative Dentistry
The science and art in Dentistry that studies the prevention, diagnosis and treatment of defects/disease in the enamel and dentin.
Carious
Bacterial infection, removal of tissue, precise cavity prep.
Non-carious
Loss due to chemical or mechanical abrasion. Attrition, abrasion, erosion, abfraction
Attrition
Breakdown from pressure
Abfraction
Angular notch caused by bending of tooth
Direct Restoration
Soft material placed then hardened.
Indirect Restoration
Formed outside body then cemented or bonded to tooth
Airdriven vs. Electric
Volume, higher power, less stalling
Slow speed
12000 RPM, no water coolant, close to pulp removal, surface polishing and finishing.
Medium Speed
12-20 thousand
High Speed
> 200000, needs water coolant, most cutting.
Most common connector line
4 hole
Slight angle
Contrangled
Base of hand piece
coupler
Push button
One chuck mechanism
Nose cone
Straight attachment, slow speed, extraoral work, long shank type bur, straight bur.
2 latch type head
Swing latch
Friction Grip head
Slow speed, push/screw
Rotary Cutting Instruments 3 components
Head neck shank
3 types of rotary instruments
Bladed, Diamond (abrasive), Other (?)
Tapered neck - why
Visibility
Bladed instruments
Excavating, Finishing
Finishing burs
10-30 blades - 10-12 red, 16-20 yellow, 30 white
Excavating/cutting burs
6-8 blades
Blade cutting composition/use
Tungsten carbide, intracoronal prep
Diamond for abrasive cutting
metal blank with diamond for extracoronal preps.
Diamond colors
Supercoarse to superfine: black, green, blue, red, yellow
Other (type of rotary instrument)
Discs (attached via handpiece via mandrel for finishing restorations), Molded (grinding etc.)
Round (Blade design)
1/4 -4 (0.5 mm to 1.4 mm)
Inverted Cone (blade design)
331/2-40
Pear shaped (blade design)
330 (1.5 mm, diam = 0.8mm, taper = 8deg), 245 (length - 3mm, taper = 4deg, diam = 0.8mm)
Plain Cylindrical Fissure
55-59 (200 series for rounding corners)
Plain Tapered Fissure
169-172
Head design - end cutting
End only has blades - 900s
Cross cut
500 before bur number, also 700
Fracture types
Brittle, ductile
Brittle fracture
ABRASIVE CUTTING IS BEST for extracoronal preps - diamond bur Tensile loading causes cracks in enamel, helps break
Ductile Fracture
Deformation by shearing - dentin Bladed cutting is best (deform then shear) - best for intracoronal preps
Rake face
Blade surface toward cutting, forms chip
Clearance face
Surface that clears the chips- away from cutting direction
Rake angle
Rake to axis of bur
Edge angle
Rake face to clearance face
Clearance angle
Clearance face to tangent (cutting edge to tooth surface) - prevents blade from rubbing on tooth surface, bigger clearance angle = less friction = longer bur life
Positive vs negative rake angle
More efficiency and less durable. Higher cutting efficiency, more chips made, less chip space (clogging)
Patient hazard of cutting instruments
Heat and vibration can lead to pulpal trauma (water coolant helps this)
Hand instrument components
Handle, shank, working end (nib/point for non cutting, blade for cutting)
Non-cutting
Examination instruments (mirror, explorer, perio probe)
Hand-cutting
shape walls for finer detail - blade is carbon steel, handle is stainless steel
Restorative instruments (noncut)
place material and carve material - carrier, condenser/plugger, anatomical/acorn burnisher
accessory instruments
aid procedure- miller forceps (paper holder), amalgam well
Mirror
left hand, retraction of tissue and protection.
Explorer
Pointed tip (enhanced tactile) for caries detection
Perio probe
depth
Blade edges
Primary/2 secondary cutting edges
Blade edge types
Straight, mono angled, bin angle, triple angle
Balance
Blade tip in line with center of tool
Black’s Instrument Formula
1st: width of blade in 1/10mm, 2nd: blade length in mm, 3rd: Angulation w/respect to long axis (100ths, lower than 50)
4 number formula
1st, 2nd to 3rd, 3rd to 4th, new 2nd: primary cutting edge angle (100ths greater than 50)
Single bevel
right triangle
Bibevel
isosceles triangle
Triple bevel
Rec/bibeveled on 3 sides
Direct cutting
Perpendicular force, hatchet used
Indirect cutting/lateral cutting
Parallel force
Chisels
Straight, slightly curved, bin angled hatchets, enamel hatchet, gingival margin trimmer
Enamel hatchet
lateral cutting and direct cutting
Gingival margin trimmer
lateral cutting, curved blade to facilitate this
Excavator
Ordinary hatchet, hoes (pull), angle former, spoon