Instrument Design And Classification Flashcards
What is optimal instrument weight and why?
15 g or less
Light weight design places less stress on hand muscles are acquires less pinch force
What is optimal handle diameter?
3/8 inch- Large diameter requires less pitch force
Optimal handle texture
Knurling pattern
Increases static friction btw fingers and handle
What to avoid when choosing a handle
Heavy, solid handle
Small diameter
Non-textured
What is pinch force?
Refers to force used to grasp the handle during instrumentation
Larger handle diameters and light weight requires less pinch force
When is a periodontal i strument balanced?
When the working ends are aligned with the long axis of the handle
Ends are centered with the midline of the handle
Why is it important for instruments be balanced?
Ensures that finger pressure applied is transferred to the working end for calculus removal
Unbalanced= difficult to use and stresses muscles
What is the reason for shank bends?
To facilitate placement of the working end against the tooth surface
Characteristics of a simple shank
Will appear straight
For use on anterior teeth
Adequate to reach along the crown and onto the root of wedge shaped anterior teeth
Describe complex shank design
Side to side bends
Bent in 2 places
For use on posterior teeth. Large bulky crowns have greater diameter than the roots. Bends allow for adaptation to facial/lingual/proximal surfaces of the root
Describe rigid shanks
Remove heavy deposits. Can withstand pressure
Describe flexible shanks
Remove small to medium deposits
Enhance tactile info trsnsmitted to fingers
Desireable for explorers, vibrations created when moved over tooth surface irregularities
What is the functional shank
Portion of the shank that allows the working end to be adapted to the tooth surface
Begins below the working end and extends to the last bend in the shank near the handle
What is the lower shank
Portion if the functional shank that is nearest to the working end; also called the terminal shank
Used for ID of correct working end
What is the purpose of an extended lower shank?
Can reach the middle and apical thirds of the root surface
What is the use of a simple shank with short functional shank length?
Supragingival used on anterior teeth
What is the use of a simple shank with a long functional shank length?
Subgingival use on anterior teeth
What is the use of a complex shank with short functional shank length?
Supragingival use on posterior teeth
What is the use of a complex shake with a long functional shank length?
Subgingival use on posterior teeth
What are some examples of instruments that may be single ended?
Periodontal probe, explore and spatula
Which instruments are frequently double ended?
Curetes
May be paired or unpaired
What is the difference between paired and unpaired working ends?
Unpaired gave dissimilar working ends, paired have mirror image working ends
Features of instrument identification
Design name and design number
Design name is school or person who designed the instrument and the design number identifies the working ends
Parts of the working end
Face, back, lateral surfaces (either side), cutting edges (Sharp edge formed where the face and lateral surfaces meet), toe (rounded) or tip (pointed)
Most working ends have two cutting edges
What is the significance of instrument cross section?
Determines whether the instrument can be used sub gingivally or is restricted to supragingival use
Instrument use for those triangular in cross-section
Limited to supragingival use
Instrument use for those semi circular in cross-section
Used supragingivally and subgingivally
What are the two classifications of periodontal instruments?
Assessment instruments and calculus removal instruments
What are the two types of assessment instruments?
Periodontal probes and explorers
What are the three types of calculus removal instruments?
Sickle scalers, curettes and periodontal files
What is a periodontal probe?
Slender instrument used to evaluate the health of the gums
Blunt, rod shaped working end
What is an explorer?
Used to locate calculus deposits, tooth irregularities and defective restoration margins. Circular in cross-section
What are sickle scalers used for?
Used to remove supragingival calculus deposits. Triangular and cross-section has a tip with a pointed back
What are curettes used for?
Used to remove supra or sub gingival calculus deposits. Semi circular in cross-section with a toe and a rounded back
What is a periodontal file?
Used to crush large calculus deposits. Each working and has several cutting edges
