Op 1 Flashcards
What is the 4 number instrument formula used for?
margin trimmers
What do these numbers represent: 15-98-10-14?
15 = 1.5mm width
98 = angle of cutting edge to long axis of handle
10 = 10mm blade length
14 = angle of blade to long axis of handle
What are 3 functions of hand instruments?
Removes loose enamel
Smooths preparation
Refines cavity features
What are 2 examples of refining cavity features?
Retention areas
Line angles
What are the 2 metals in hand instruments?
Stainless steel
Carbon steel
What are the features of stainless steel?
Resists corrosion
Dulls easily (need to keep instruments sharp)
What are the features of carbon steel?
Corrodes
Holds sharpness
What are the 3 types of hand instruments?
Hand cutting instruments
Restorative instruments
Plastic instruments
What are the hand cutting instruments (examples)?
chisels, hatchets, hoes, gingival margin trimmers, excavators, carvers
What is the most common excavator used?
spoon
Characteristics of chisels
Straight or curved
1, 2, or 3 angles
Characteristics of hatchets
Cutting edge = in plane parallel with handle
1 or more angles
Do not use with too much force or twist (can easily break)
Characteristics of hoes
Cutting edge is ⟂ to handle
Characteristics of gingival margin trimmer
Similar to hatchet, but has curved blades
Cutting edge is at angle to length of blade
Characteristics of excavators
Remove caries
Characteristics of carvers
Place anatomy
What are restorative instruments used for?
Used to place, condense, and carve restorative materials back to normal anatomy of teeth
What are restorative instruments primarily made of?
Stainless steel
What are the restorative instruments (examples)?
amalgam carrier, condensers, burnishers, carvers, amalgam knife, composite placement instruments
Characteristics of condensers (aka amalgam plugger)
Condenses materials
Can be used to gauge cavity width
Characteristics of plastic instruments
Can be used to carry pliable restorative material to prepped cavity (although typically placed directly by composite gun)
Used to shape material
What are the 3 parts of hand instruments?
Shaft/handle
Shank
Blade
Characteristics of shaft/handle of a hand instrument
Can be small, medium, large
Smooth or serrated
Characteristics of shank of a hand instrument
Connects handle to blade
Straight or angled
(Angled for access and stability)
Characteristics of blade of a hand instrument
Working part of the instrument
Beveled to create cutting edge
How many bevels can the blade of a hand instrument have?
3
Where is the primary cutting edge of the blade of a hand instrument?
on the end
Where is the secondary cutting edge of the blade of a hand instrument?
on the sides
Can hand instruments be double ended? Or just single ended?
They can be double ended (2 working sides) or a long handle with 1 working side
What are the 3 categories for sterilization?
Critical
Semi-critical
Non-critical
What does critical mean in regards to sterilization? Give an example
Penetrates soft tissue of bone
Ex: forceps
How do we sterilize critical instruments?
Autoclave (most commonly used heat sterilizer in dentistry)
What does semi-critical mean in regards to sterilization? Give an example
Does not penetrate, but contacts mucous membranes or non-intact skin
Ex: mirrors
How do we sterilize semi-critical instruments?
Autoclave or high level EPA sterilant/disinfectant
What does non-critical mean in regards to sterilization? Give an example
Comes in contact only with intact skin
Ex: blood pressure cuff
How do we sterilize non-critical instruments?
Intermediate or low level disinfectant
How many classes of carious lesions are there? Which one is most and least prevalent?
6 (I-VI)
Most prevalent = Class I
Least prevalent = Class VI
Where are caries on Class I lesions?
Pits and fissures on:
-Occlusal ⅓ of molars and premolars
-Occlusal ⅔ of B & L surfaces of molars and premolars
-L surface of upper anterior teeth
-Any other unusually located pit or fissure
What is the general rule of pit/fissure lesions? (Class I)
More constricted at enamel surface and wider toward DEJ
Where are caries on Class II lesions?
Caries affecting proximal surfaces:
-Molars and premolars
What is the general rule of smooth surface interproximal lesions? (Class II)
Wider at enamel surface
Where are caries on Class III lesions?
Caries affecting proximal surfaces of:
-Central and lateral incisors
-Cuspids without involving incisal angles
Where are caries on Class IV lesions?
Caries affecting proximal surfaces including incisal angles of anterior teeth
Where are caries on Class V lesions?
Caries affecting gingival ⅓ of facial or lingual surfaces of:
-Anterior teeth
-Posterior teeth
Where are caries on Class VI lesions?
Caries affecting cusp tips of:
-Molars
-Premolars
-Cuspids
What is abrasion?
Tooth surface loss from frictional forces
What is erosion?
Tooth surface loss from chemico-mechanical action
What is attrition?
Mechanical wear from opposition teeth (grinding)
What is abfraction?
Cervical, wedge-shaped defects as result of strong eccentric occlusal forces
What is fracture?
Can be most difficult and challenging defects in teeth to diagnose and treat
Can be considered incomplete or complete; involving pulp or not involving pulp
What are the 4 stages of caries progression?
Demineralization
Cavitation
Infected dentin
Affected dentin
What is demineralization?
Loss of mineral from tooth structure, resulting from a chemical process (can be from caries, acid, diet, or gastric)
What is cavitation?
Breakdown of surface integrity that can be detected using optical or tactile methods
Where can cavitation go?
Can be confined to enamel or extend into dentin via tubular invasion
What can cavitation include?
Differing layers of infected and affected dentin
How do caries penetrate (shape)?
Penetrate in a narrow or cone shaped channel to DEJ then spread laterally
What is infected dentin?
Irreversible, demineralized, and denatured layer with bacterial invasion
Very soft, moist, and easy to remove with spoon excavator
What is affected dentin?
Partially demineralized
Leathery/softer than normal
Collagen is not denatured
Contains minimal to no bacteria
What are the forms of tooth prep?
Outline
Convenience
Resistance
Retention
What is the outline form?
External shape of the prep
What do we consider when it comes to outline form?
Access to lesion
Extent of lesion
Restorative material being used
Esthetics
Function
What does access to lesion refer to in regards to outline form?
Visualize extent of caries
Allows bur to reach all carious dentin
Creates space for instrumentation and vision
You should extend your outline to include all ________ enamel, because enamel rods must be supported by _______ ___.
You also should include the ____ spread of caries at ____. Carious dentin can have ____ overlying dentin; ____ enamel is usually removed.
________ enamel can be considered for ____.
Unsupported; sound dentin
Lateral; DEJ; sound; undermined
Decalcified; inclusion
What determines the size of the prep?
Extent of caries in dentin
You should design your prep to take advantage of/compensate for what?
For properties of material to be used
What do brittle materials like amalgam and porcelain require when creating the outline form?
90° cavosurface margin
What do ductile materials like composite and gold require when creating the outline form?
Beveling of margin
What do esthetics refer to in regards to outline form?
Restorations in visible areas of mouth dictate cavity design and restoration selection
What does function refer to in regards to outline form?
When a restoration alters occlusion, outline may need to be altered
Do not leave occlusal contact on margin of restoration EVER
What is the convenience form?
Shape that allows access for the procedure to be done
Allows vision, access, and ease of instrumentation and insertion of restorative materials (influences outline form too)
What is the resistance form?
Shape given to prevent fracture of either the restoration or the tooth
What are examples of resistance form?
Adequate bulk of amalgam
Rounding of internal line angles
Horizontal pulpal and gingival floors prepared ⟂ to tooth’s long axis
What is the consideration of resistance form? What are the 3 reasons?
Prep is placed 0.5mm into dentin (not including enamel) for 3 reasons:
Avoid sensitive DEJ
Provide adequate bulk of restorative material
Take advantage of dentin’s resilience