instruments of design and classification module 8

unpaired working-ends

instrument with 2 dissimilar working-ends

paired working-ends

instrument with working-ends that are mirror images

design name

school or person who designed the instrument

ex. gracey named after dr gracey

design number

identifies the working-ends

each working end is identified by

by the number closest to it

ex. gracey 1 2

1 is the left working-end, and 2 is the right working-end

if the number wraps around the handle, not along it

• the first number after the name identifies the working-end at the top

• the second number identifies the working-end at the lower end of the handle

3 parts of an instrument

• handle

• shank

• working-end

choosing the right handle

recommened

• larger diameter

• lightweight handle

• bumpy texture

choosing the right handle

avoid

• small diameter

• heavy, solid metal handle

• smooth or flat texturing

a periodontal instrument is balanced if the

working ends are aligned with the long axis of the handle

significance of balance

• ensures that finger pressure applied against the handle is transferred to the working-end for calculus removal

• an instrument that is not balanced is difficult to use and stressed the muscles of the hand

simple shank design is for

anterior teeth

complex shank design is for

posterior teeth

why is a simple shank chosen for anterior teeth?

• anterior teeth are wedge-shaped

• a simple shank is adequate to reach along the crown and onto the root

why is a complex shank chosen for posterior teeth

• posterior teeth have large, bulky crowns that are larger in diameter than the roots

• a complex shank is needed for posterior teeth

complex shank for facial and lingual surfaces

front-to-back shank bends allow you to reach the facial and lingual surfaces of the root

complex shank for proximal (mesial) surfaces

side-to-side bends allow you to reach the mesial and distal surfaces of the root

functional shank

the portion of the shank that allows the working-end to be adapted to the tooth surface

lower shank

the portion of the functional shank that is nearest to the working-end; aka the terminal shank

a simple shank with a short functional shank length is for

supragingival (above gumline) use on anterior teeth

a simple shank with a long functional shank length is for

subgingival (below gumline) use on anterior teeth

a complex shank with short functional shank length is for

supragingival (above gumline) use on posterior teeth

a complex shank with a long functional shank length is for

subgingival (below gumline) use on posterior teeth

instruments with longer shanks can reach

the middle and apical third of the root surface

an instruments function is determined primarily

by the design of it’s working-end

to determine the instruments use,

you must recognize the design characteristics of the working-end

• face

• back

• lateral surfaces

• cutting edges

• toe or tip

face of a working end

is inside the cutting edges

the back of a working end

is the surface opposite of the face

the lateral sides of the working end

are the surfaces on either side of the face

the cutting edge of the working end

is the sharp edge formed where the face and lateral surfaces meet; most working ends have 2 cutting edges

toe of a working end

the cutting edges meet to form a rounded toe; curet

tip of a working end

the cutting edges meet to form a pointed tip; scaler

working ends that are triangular in cross section (scaler)

are limited to SUPRAGINGIVAL use; but can be adapted to be used subgingivally

working ends that are semi-circular in cross section (curet)

may be used supra and subgingivally

periodontal instruments are divided into

types or classifications, based on specific design characteristics of the working ends

• assessment instruments

• calculus removal instruments

assessment instruments

• periodontal probes

• explorers

calculus removal instruments

• sickle scalers

• curets

• periodontal files

periodontal probe

a slender instrument used to evaluate the health of the periodontal tissues

blunt, rod shaped working ends

calibrated periodontal probe

marked off in millimeter increments for measurements

furcation periodontal probe

blunt, rod shaped working ends that are rectangular or circular in cross-section

explorer

used to locate calculus deposits and tooth irregularities

• designed with a think flexible shank to provide excellent tactile sensitivity

• has fine wirelike working end that terminates in a sharp point and is circular in cross section

scaler

used to remove supragingival calculus deposits

• triangular is cross-section

• pointed tip

• pointed back

curet

used to remove calculus deposits

• semi circular is cross-section

• rounded toe

• rounded back

universal curet

• cutting edges parallel to one another

• face of blade is at 90 degree angle to shank

area-specific curet

• face is tilted in relationship to lower shank (60-70 degrees)

• designed for use in specific area

periodontal file

used to crush large calculus deposits

• each working end has several cutting edges

• WE WILL NOT USE!