Instrument Design PDF

Module 8—Instrument Design and Classification Section 1 Design Characteristics of Instrument Handle Copyright © 2014 Wolters Kluwer All Rights Reserved  Topics -Instrument handle design -Instrument balance...

Module 8—Instrument Design and Classification Section 1 Design Characteristics of Instrument Handle Copyright © 2014 Wolters Kluwer All Rights Reserved  Topics -Instrument handle design -Instrument balance 2 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Instrument Handles 3 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Significance of Instrument Design -Design characteristics of periodontal instruments vary widely among manufacturers -Instruments with ergonomic design help prevent musculoskeletal injury during instrumentation -Consider handle, shank, and working-end design 4 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Parts of a Periodontal Instrument 5 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Variations in Handle Design Handle design is important in prevention of musculoskeletal injury during instrumentation Handle characteristics to consider: – Instrument weight – Handle diameter – Taper – Texture 6 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Examples of Handle Designs 7 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Pinch Force -Repetitive forceful pinching of an instrument can be a risk factor for carpal tunnel syndrome -Refers to force used to grasp the handle during instrumentation -Larger handle diameters and lightweight handles require less pinch force More pinch force = muscle cramping 8 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Choosing the Right Handle RECOMMENDED AVOID -Lightweight handle -Heavy, solid metal -Large diameter handle -Tapered handle -Small diameter -Raised texturing -Nontapered handle (knurling pattern) -No texturing or nonraised texturing 9 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Instrument Balance 10 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company A periodontal instrument is balanced if the working-ends are aligned with the long axis of the handle. 11 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Balanced? -Balanced if the working- ends are centered with the midline of the handle A = Not balanced B = Balanced 12 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  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 stresses the muscles of the hand and arm 13 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Summary: Recognize Design Features -Instrument handles available in a variety of weights, diameters, and textures -Instrument balance impacts stress on muscles 14 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Section 2 Design Characteristics of Instrument Shank Copyright © 2014 Wolters Kluwer All Rights Reserved  Topics -Simple and complex shank designs -Shank flexibility -Functional and lower shank portions -The best instrument for a task -Specialized instruments with extended lower shanks 16 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Shank Bends The shanks of most periodontal instruments are bent in one or more places to facilitate placement of the working-end against the tooth surface. 17 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Simple Shank Design -Hold the instrument so that the working-end tip or toe is facing you -Simple shank will appear to be straight 18 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Complex Shank Design -Hold the instrument so that the working-end tip or toe is facing you -Complex shank has side-to-side bends 19 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Comparison of Shank Designs Simple shanks: for use on anterior teeth (also called straight shanks) Complex shanks: for use on posterior teeth (also called angled or curved shanks) 20 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Selecting the Right Shank for the Task Should I select an instrument with a simple shank design or a complex shank design? 21 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Anteriors: Simple Shank Anterior teeth are wedge shaped. A simple shank is adequate to reach along the crown and onto the root. 22 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Posteriors: Complex Shank Posterior teeth have large, bulky crowns that are larger in diameter than the roots. A complex shank is needed for posterior teeth. 23 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Complex Shank: Facial and Lingual The illustration shows a molar when viewed from the mesial aspect. Front-to-back shank bends allow you to reach the facial and lingual surfaces of the root. 24 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Complex Shank: Proximal Surfaces The illustration shows a molar when viewed from the facial aspect. Side-to-side bends allow you to reach the mesial and distal surfaces of the root. 25 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Shank Flexibility 26 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Strength of Instrument Shank -Clinician applies pressure against handle and shank to remove calculus deposits -Type and diameter of metal determines strength: – Rigid shank—removes heavy deposits – Flexible shank—removes small to medium deposits 27 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Flexible Shank Characteristics -Enhances amount of tactile information transmitted to clinician’s fingers -Desirable for explorers used to detect deposits beneath gingival margin -Vibrations are created when working-end quivers over tooth surface irregularities -Vibrations are transmitted from working-end, through the shank, and into the handle 28 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Regions of the Shank 29 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Functional and Lower Portions 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; also called the “terminal” shank 30 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Functional Shank -Begins below the working-end, and extends to the last bend in the shank nearest the handle 31 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Lower Shank -The portion of the functional shank nearest to the working- end 32 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Functional and Lower Shanks 33 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Selecting the Best Instrument for a Task 34 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Instrument Use: Simple Shank -Simple shank with short functional shank length: supragingival use on anterior teeth -Simple shank with long functional shank length: subgingival use on anterior teeth 35 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Complex Shank Use -Complex shank with short functional shank length: supragingival use on posterior teeth -Complex shank with long functional shank length: subgingival use on posterior teeth 36 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Specialized Instruments with Extended Lower Shanks 37 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Extended Lower Shanks Instrument A has a standard lower shank. Instrument B has an extended lower shank. 38 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company Use: Extended Lower Shank Instruments with extended lower shanks can reach the middle- and apical-third of the root surface. 39 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Important Shank Characteristics -Determine if shank is simple or complex -Recognize shank flexibility -Recognize the functional shank -Recognize the lower shank -Recognize an extended lower shank 40 Copyright © 2016 by Jones & Bartlett Learning, LLC, an Ascend Learning Company  Section 3 Design Characteristics of Instrument Working-End Copyright © 2014 Wolters Kluwer All Rights Reserved  Topics -Single- and double-ended instruments -Instrument identification -Parts of the working-end -Working-end in cross section -Introduction to instrument classification 42 Copyright © 2017 Wolters Kluwer All Rights Reserved Single- and Double-Ended Instruments 43 Copyright © 2017 Wolters Kluwer All Rights Reserved  Single-Ended Instruments Periodontal instruments are available in single ended, such as this periodontal probe. 44 Copyright © 2017 Wolters Kluwer All Rights Reserved  Double-Ended Instruments -Curets are frequently double-ended instruments -Double-ended instruments may have: – Unpaired working-ends – Paired working-ends 45 Copyright © 2017 Wolters Kluwer All Rights Reserved  Double-Ended Instruments (cont.) -Unpaired working-ends have dissimilar working- ends -Paired working-ends have mirror image working- ends 46 Copyright © 2017 Wolters Kluwer All Rights Reserved  Unpaired Versus Paired Instrument A - Unpaired Instrument B - Paired 47 Copyright © 2017 Wolters Kluwer All Rights Reserved Instrument Identification 48 Copyright © 2017 Wolters Kluwer All Rights Reserved  Design Name Design Name: school or person who designed instrument (e.g., Gracey) 49 Copyright © 2017 Wolters Kluwer All Rights Reserved  Design Number Design Number: identifies the working-ends (e.g., 1 and 2) 50 Copyright © 2017 Wolters Kluwer All Rights Reserved Working-End Identification 51 Copyright © 2017 Wolters Kluwer All Rights Reserved  Number Along Handle Each working-end is identified by the number closest to it. 52 Copyright © 2017 Wolters Kluwer All Rights Reserved  Number Around Handle (cont.) The first number (on the left) identifies the working-end at the top. The second number is the working-end on the lower end of the handle. 53 Copyright © 2017 Wolters Kluwer All Rights Reserved  Working-End Design An instrument’s function is determined, primarily, by the design of its working-end. To determine an instrument’s use, you must recognize the design characteristics of the working-end. 54 Copyright © 2017 Wolters Kluwer All Rights Reserved  Overview: Parts of Working-End Face Back Lateral surfaces Cutting edges Toe or tip 55 Copyright © 2017 Wolters Kluwer All Rights Reserved  Face and Back The shaded surface on this illustration is the face. The surface opposite the face is the back of the working-end. 56 Copyright © 2017 Wolters Kluwer All Rights Reserved Lateral Surfaces The surfaces on either side of the face are called the lateral surfaces of the working-end. 57 Copyright © 2017 Wolters Kluwer All Rights Reserved  Cutting Edge The cutting edge is a sharp edge formed where the face and lateral surfaces meet. Most working-ends have two cutting edges. 58 Copyright © 2017 Wolters Kluwer All Rights Reserved  Toe This is a birds-eye view, looking down on the face. On some working-ends the cutting-edges meet to form a rounded toe. 59 Copyright © 2017 Wolters Kluwer All Rights Reserved  Tip This is a birds-eye view, looking down on the face. On some working-ends the cutting-edges meet to form a pointed tip. 60 Copyright © 2017 Wolters Kluwer All Rights Reserved The Working-End in Cross Section 61 Copyright © 2017 Wolters Kluwer All Rights Reserved The cross section of a working-end is exposed by cutting through the working-end at right angles to its longest dimension. 62 Copyright © 2017 Wolters Kluwer All Rights Reserved  Significance of Cross Section The cross section of a working-end determines whether the instrument can be used subgingivally—beneath the gingival margin—or is restricted to supragingival use. 63 Copyright © 2017 Wolters Kluwer All Rights Reserved  Instrument Use Working-ends that are triangular in cross section are limited to supragingival use. Working-ends that are semi-circular in cross section may be used supragingivally and subgingivally. 64 Copyright © 2017 Wolters Kluwer All Rights Reserved Creating a Cross Section Saw a pencil into two parts by cutting it in the middle perpendicular to the long axis of the pencil. 65 Copyright © 2017 Wolters Kluwer All Rights Reserved Hexagonal Cross Section The pencil is hexagonal in cross section. A hexagon is a six- sided figure. 66 Copyright © 2017 Wolters Kluwer All Rights Reserved Working-End Cross Section Imagine cutting the working-ends of these instruments in half to reveal the cross section. 67 Copyright © 2017 Wolters Kluwer All Rights Reserved Shape of Cross Section -One working-end is semi-circular in cross section -The other is triangular in cross section 68 Copyright © 2017 Wolters Kluwer All Rights Reserved Semi-Circular Cross Section Curets are instruments that are semi-circular in cross section. Curets may be used supragingivally and subgingivally. 69 Copyright © 2017 Wolters Kluwer All Rights Reserved Triangular Cross Section Sickle scalers are instruments with triangular cross sections. Sickle scalers are limited to supragingival use. 70 Copyright © 2017 Wolters Kluwer All Rights Reserved  Introduction to Instrument Classification 71 Copyright © 2017 Wolters Kluwer All Rights Reserved Periodontal instruments are divided into types, or classifications, based on the specific design characteristics of the working-ends. 72 Copyright © 2017 Wolters Kluwer All Rights Reserved Classification of Instruments 73 Copyright © 2017 Wolters Kluwer All Rights Reserved Periodontal Probe -A slender instrument used to evaluate the health of the periodontal tissues -Blunt, rod-shaped working-end 74 Copyright © 2017 Wolters Kluwer All Rights Reserved  Explorer -Used to locate calculus deposits, tooth irregularities, and defective restoration margins -Circular in cross section 75 Copyright © 2017 Wolters Kluwer All Rights Reserved  Sickle Scaler -Used to remove supragingival calculus deposits -Triangular in cross section -Pointed tip -Pointed back 76 Copyright © 2017 Wolters Kluwer All Rights Reserved  Curet -Used to remove calculus deposits -Semi-circular in cross section -Rounded toe -Rounded back 77 Copyright © 2017 Wolters Kluwer All Rights Reserved Periodontal File -Used to crush large calculus deposits -Each working-end has several cutting edges 78 Copyright © 2017 Wolters Kluwer All Rights Reserved  Skill Application -Practice identifying parts of the working-end and shank -Use various colors of nail polish to paint and identify the following on several instruments: – Face and lateral surfaces of working-end – Functional and lower shanks 79 Copyright © 2017 Wolters Kluwer All Rights Reserved  Summary An instrument’s function is determined, primarily, by the design of its working-end. To determine an instrument’s use, you must recognize the design characteristics of the working-end. 80 Copyright © 2017 Wolters Kluwer All Rights Reserved