operative instruments

1. PRESENTED BY, SHIJI MARGARET FINAL BDS DEPARTMENT OF CONSERVATIVE DENTISTRY AND ENDODONTICS OPERATIVE INSTRUMENTS

2. CONTENTS Introduction Classifications of instruments Instrument parts Instrument nomenclature Instrument formula Exploring instruments Instrument design Restorative instruments Classification Types Dental burs Classification of burs Bur design conclusion Reference

3. CLASSIFICATION GV BLACKS classification 1.Cutting instruments a. Handcutting instruments -hatchets -chisels -hoes -excavators b. Rotary instruments - burs -stone -discs

4. 2. Condensing instruments a. pluggers -hand -mechanical 3. Plastic instruments -plastic filling instruments -cement cariers - carvers - burnishers - spatulas

5. HAND Orangewood sticks Polishing points Finishing strips ROTARY Finishing burs Mounted brushes Mounted stones Rubber cups 4. Finishing and polishing instruments

6. 5. Isolation instruments Rubber dam Saliva ejector Cotton roll holder Evacuating tips and equipment

7. 6. Miscellaneous instruments mouth mirrors explorers probes scissors pliers others

8. MARZOUCK CLASSIFICATION Exploring instruments - tweezers - Retractors - Probes - Separators Instruments for tooth structure removal a. hand cutting -excavators - chisels -special form of chisel b. handpiece -burs - ultrasonic

9. INSTRUMENT PARTS . a . blade . b. shank. c. handle

10. . SHAFT Used as a handle , is straight without variations in size. It may be serrated to increase friction for hand gripping.

11. SHANK It connects the handle to the blade. It is here where any angulation in the instrument can be given.

12. BLADE It is the functional end of the instrument.It is connected to the handle by the shank. The blade ends in cutting edge.

13. CUTTING EDGE . It is the working part of the instrument . It is usually in the form of a bevel with different shapes BLADE ANGLE. It is defined as the angle between the long axis of the blade and long axis of the shaft CUTTING EDGE ANGLE . It is defined as angle between the margin of the cutting edge and the long axis of the shaft .

14. INSTRUMENT NOMENCLATURE G. V Black described dental instruments as follows. The order denotes the purpose of the instrument , eg excavator , scaler . The suborder denotes the position or manner of use of the instrument ,e.g. push or pull. The class describes the form of the blade ,e.g. hatchet, chisel. The subclass denotes the angle or shape of the shank.e.g straight- no angle

15. INSTRUMENT FORMULA The width of the blade in tenths of millimeters. The primary cutting edge angle formed between cutting edge and central axis of shaft. The length of the blade in millimeters. The blade angle in centigrade .

16. EXPLORING INSTRUMENTS MOUTH MIRRORS TYPES OF MIRROR SURFACES 1 a. front surface reflecting mirror b. rear surface reflecting mirror 2. a. plane or flat surface b. concave surface 3. a. one sided b. two sided

17. USES Direct vision Indirect illuminaton Transillumination Retraction

18. EXPLORER Diagnostic aid in evaluating condition of teeth especially in pits and fissures PARTS Straight explorer Shephered’s crrok or curved explorer Interproximal explorer

19. TWEEZERS They have angled tip and available in different sizes. They are used to place and remove cotton rolls and other small materials. PERIODONTAL PROBES They are used for measuring pocket depth.

20. INSTRUMENT DESIGN . Direct cutting and lateral cutting instruments. Contrangling . Right and left instruments. Single bevelled instruments. Bibevelled instrument. Triple bevelled instruments. Circumferentially bevelled instruments. Single ended and double ended instruments.

21. A direct cutting instrument : The force applied in the same plane as that of the blade and handle ; it is called single planed instrument. Have 2 or more curves or angles in their shanks ,and in the same plane as the handle. Used in direct or lateral cutting. 1.DIRECT CUTTING AND LATERAL CUTTING INSTRUMENTS.

22. Lateral cutting instruments : The force applied at a right angle to the plane of blade and handle. Are called double planed instruments Have an angle or curve in a plane at a right angle to that of handle. Used in lateral cutting .

23. Have one or more angles in shank placing the working point within 3mm from the axis of handle. This principle of design is called contrangling . A short blade and small blade angle requires only bi angle- contrangling . While longer blade and greater blade angles requires triple angle contrangling . 2.CONTRANGLING .

24. Direct instruments are made either right or left by placing a bevel on one side of the blade. If the the cutting edge down and pointing away from the operator and the bevel is on the right side ,it will be’ right’ instrument. If the bevel is on the left ,it will be a left instrument. These are all single planed instruments. . 3 .RIGHT AND LEFT INSTRUMENTS .

25. SINGLE ENDED AND DOUBLE ENDED INSTRUMENTS. Double ended instruments incorporating the right and left or the mesial and distal form of the instrument in the same handle. Single ended instrument have only one specific function.

26. EXCAVATORS These are designed for excavation removal of carious dentin and for the shaping of the internal parts of cavities. HOE EXCAVATOR. SPOON EXCAVATOR. DISCOID EXCAVATOR. CLEIOD EXCAVATOR. HATCHET EXCAVATOR.

27. SPOON EXACAVATORS. A B C A.bin-angle spoon B.Triple angle spoon C.spoon

28. Used for cutting mesial and distal walls of premolars and molars. HOE EXCAVATOR.

29. DISCOID EXCAVATOR These are disc like . Have a blade which is circular in shape. Cutting edge extending around the periphery except where it is joined to the shank. It is used for the same purpose and in the same manner as a spoon excavator. It is double –planed instrument right or left cutting movements.

30. It resembles a claw ,hence the name “ cleoid ”. It is essentially a spoon excavator except the blade comes to a point. It is double –planed instrument with lateral cutting movements. Used in carving amalgam and excavating decay. CLEOID EXCAVATOR.

31. CHISEL These are intended for cutting enamel. It usually bevelled on one side . STRAIGHT CHISEL. MONO ANGLE CHISELS. BI ANGLE CHISELS. TRIPLE ANGLE CHISELS.

32. STRAIGHT CHISELS. Have a straight blade in line with the handle and shank. The cutting edge is on one side only, with the bevel of the hand running at a right angle to the shaft. They are single planed instruments with 5 possible cutting movements.

33. ENAMEL HATCHET. The shank has one or more angles or curves. The blade is in same plane ,parallel with the shaft. Cutting edge is in the form of a bevel parallel to the shaft; either paired or may be bibevelled . These are single planed instruments with vertical, push, pull, and either right or left lateral cutting. Smaller size for anterior teeth, and larger size for posterior teeth

34. SPECIAL FORMS OF CHISELS These designed to perform specific functions. ENAMEL HATCHETS. GINGIVAL MARGIN TRIMMERS. ANGLE FORMERS. WEDELSTEADT CHISELS. OFFSET HATCHETS. TRIANGULAR CHISELS. HOE CHISELS. HATCHETS OR OFFSET HATCHETS.

35. GINGIVAL MARGINAL TRIMMERS. Similar to spoon excavators and the cutting edge similar to single bevelled hatchets. 2 types are; Distal gingival margin trimmers. Mesial gingival margin trimmers. They are used for creating the proper bevel of the gingival floors and also for forming sharp angles in internal parts of cavity preparations. They are also used in pull and push motions.

36. RESTORATIVE INSTRUMENTS CEMENT SPATULAS Several types of spatulas are available in the market differing in shape and size. On the basis of size, cement spatula can be classified into: - large - small

37. PLASTIC FILLING INSTRUMENT These instruments have a small metal ball at the working end. They are used to mix, carry and place cements. CONDENSER It is used to deliver the restoration to the tooth preparation and for proper condensation

38. AMALGAM CARRIERS To pack amalgam material in to the tooth preparation, amalgam carriers are used. They carry the freshly prepared restorative material in to the tooth. CARVERS They are used to contour the restoration. Sharp cutting edges present in carvers are used to sharpen and form tooth anatomy from a restoration.

39. BURNISHERS For final condensation of amalgam Initial shaping of occlusal anatomy of amalgam COMPOSITE RESIN INSTRUMENT A wide range of double ended instruments are used to transport and place resins They are made up of plastic or titanium coating

40. ROTARY CUTTING INSTRUMENTS Those instruments which rotate on an axis to do the work of abrading and cutting on tooth structure. TYPES : - Handpiece - Bur HANDPIECES The first rotary instruments were drill or bur heads that were twisted with the fingers for crude cutting of the tooth tissue

41. Types of hand piece Contra-angle hand piece Head of handpiece is first angled away from and then back towards the long axis of the handle a.Airoter contraangle handpiece -it gets power from the compressed air supplied by the compressor. It has high speed and low torque.

42. Micromotor handpiece In straight handpiece long axis of the bur lies in same plane as long axis of handpiece .

43. DENTAL BURS It is a rotary cutting instrument which has bladed cutting edge. They are used to remove tooth structure either by chipping or grinding.

44. Classification of burs According to mode of attachment latch type friction grip According to their composition stainless steel tungston carbide combination According to their motion right bur left bur According to the length of their head long short regular

45. According to their use cutting burs finishing burs polishing burs According to their shape round bur inverted cone bur pear-shaped wheel shaped tapering fissure straight fissure end cutting bur

46. BUR DESIGN BUR BLADE It is the projection on the bur head which forms a cutting edge.it has two surfaces rake face-surface of bur lade on the leading edge clearance face-surface of bur blade on the trailing edge

47. RAKE ANGLE -angle between rake face and radial line Positive rake angle-when rake face trails the radial line. Negative rake angle-when rake face is ahead of radial line. Zero rake angle-when rake face and radial line coincide each other.

48. RADIAL LINE It is the line connecting center of the bur and the blade. LAND It is the plane surface immediately following the cutting edge. CLEARANCE ANGLE This is the angle between the clearance face and the work.

49. BLADE ANGLE it is the angle between the rake face and the clearance face. CONCENTRICITY it is a direct measurement of symmetry of the bur head. RUN-OUT it measures the accuracy with which all the tip of blades pass through a single point when bur is moving.

50. REFERENCE 1. Sturdevants art and science of operative dentistry. 2. Marzouk . 3. Nisha Garg