HAND INSTRUMENTS IN OPERATIVE DENTISTRYMATERIAL:-Carbon steel-Stainless steel-Heat treatmentG.V. Black's classification1. Cutting instrumentsa) HandChisels,excavators,hatchets,hoes.b) RotaryBurs,stones,discs.2. Condensing instrumentsPluggers: Hand.3. Plastic instrumentsSpatulas, carriers, carvers, plastic fillinginstruments, burnishers.4. Finishing and polishing instrumentsa) HandOrangewood sticks,polishing points,finishing strips.b) RotaryFinishing burs,mounted brushes andstones, rubber cupsand discs.5. Isolation instrumentsRubber dam kit (frame, clamps, sheet, forceps, punch) saliva ejector high volume evacuatorcotton roll holder.6. Miscellaneous instrumentsMouth mirrors, probes, scissors, pliers, tweezer, etc. Marzouk'sclassification 1. Exploring instrumentsMouth mirrors, explorers, periodontal probes, cotton tweezers.2. Instruments for tooth structure removal (A) Hand cutting instruments - Chisels,excavators and special forms of chisels.(B) Rotary cutting instruments - Handpieces,burs, abrasives.3. Restoring instrumentsCement spatulas, plastic filling instruments,amalgam carriers, condensers, burnishers,carvers, files, knives.4. Finishing and polishing instrumentsFinishing strips, finishing burs, brushes, rubbercups, cloth.1. Exploring instruments Mouth mirrors Mouth mirrors are used to provide a clear and distinct vision of the operating area .Functionsi. Help in direct visualization of the field ofoperation.ii. Reflect the operating light and thusilluminate the operating area.iii. Provide indirect visualization of obscureareas of the mouth.iv. Retract the soft tissues like the tonguecheeks or lips thus aiding in better accessand visualization of the working area. Explorers These are delicate, pointed instruments use for tactile examination of tooth surface & restorations to identify any irregularities. Straight explorer Right-angled explorer Arch explorer Interproximal explorerPeriodontal probes In operative dentistry, they are useful to measure the dimensions of cavity preparations.Cotton tweezers Cotton tweezers or pliers have angled tips. They are used to place and remove cotton rolls used For isolation of teeth. They can also carry small items like cotton pellets to dry the teeth. Instruments used for removal of tooth structureBalancing In order to cut hard enamel and dentin using hand instruments, much force has to be generated at the tip of the instrument. At the same time the instrument should not rotate while it is in use. For this purpose balancing of hand instruments is done.Balancing is achieved by providing angles in the shank of the instrument so that the cutting edge of the blade is within 2-3mm of the long axis of the instrument. Balancing also provides better access and a clear view of the operating site. Instrument formulaI Unit -- Blade widthII Unit -- Blade lengthIII Unit Blade angleIV Unit Primary cutting edge angleFor instruments with four units, the IV unit is placed second in the code. The two instruments which have a four number formula are:1. Gingival margin trimmer.2. Angle former.Instrument bevels In most hand cutting instruments there is a single bevel on the end of the blade which forms the primary cutting edge. These are called single beveled instruments.Right and left beveled - Single beveled instruments are usually made in pairs having bevels on opposite sides of the blade. Mesial and distal bevels - Certain instruments have cutting edges perpendicular to the axis of the handle. motions Chopping--- Using the instrument parallelto the long axis of the blade .Pulling---Moving the instrument towards the operator's hand .Pushing---Moving the instrument away from the operator's hand Scraping---. Moving the instrument from side to side or back and forth on the tooth surface. For this motion, the blade should be held at 45 to 90 to the surface being scraped. Thrusting---Forcibly pushing the instrument against a surface.Hand cutting instruments 1. Excavators2. Chisels3. Special chisels Hatchet excavator: ordinary hatchet or the bi-beveled hatchedIn this instrument, the cutting edge of the blade is in the same plane as the long axis of the handle and is bi-beveled To sharpen internal angles, prepare retentive areas for direct filling gold restorations in anterior teeth.Hoe excavator This instrument has the primary cutting edge of the blade perpendicular to the long axis of the handle.Some hoes have longer and heavier blades with contra-angled shanks for use on enamel of posterior teeth.For planing cavity walls and forming line angles in Class III and Class V cavity preparation for direct filling gold restorationsSpoon excavatorCutting edge is semi-circular circumferential bevel & sharpened to a thin edge.Lateral cutting inst.Scooping out carious dentine, carving amalgam or direct inlay wax patternsChiselsused for cutting enamel. These have a blade which ends in a cutting edge formed by a bevel on one side only. The cutting edge of a chisel is at a right angle to the handle.Enamel hatchet Special chiselBlade is large & beveled only on one side.Cutting edge is || to long axis of the handle.Shank has one or more angle.Cut \ cleave undermined enamel in proximal cavities & on buccal & lingual walls.

Gingival margin trimmer modified enamel hatchet the blade is curved which makes it a double-plane instrument and enhances its lateral scraping action The cutting edge of the gingival margin trimmer is not at 90 to the axis of the bladeThere are two pairs of gingival margin trimmers, constituting a set of four instruments: Right and left beveled, mesial and distal types.Mesial gingival margin trimmers: The II unit in the instrument formula is 85-75 for these instruments.Distal gingival margin trimmers: The II unit in the instrument formula is 95-100 To produce a proper bevel on the gingival enamel margins of Class II cavity preparations. To round or bevel the axiopulpal line angle in Class II cavity preparations.Angle former This instrument is a combination of a chisel and gingival margin trimmer.The cutting edge angle is usually 80 - 85C making it a four unit instrument.blade of the angle former is beveled on the sides ----three cutting edges- one primary and two secondary cutting edges To accentuate line and point angles in order to create retentive points in dentin for direct gold cavity preparations.Wedelstaedt chiselResembles straight chisel ,but has a slight vertical curvature in its shank.Single plane inst.For cleaving undermined enamel.Off-set hatchets The off-set is like the regular hatchet, except the whole blade is rotated a quarter of a turn forward or backward around its long axis .useful to create and shape specific angulations for cavity walls, especially in areas of difficult accessRestoring instrumentCement spatulas flat and wide nib with blunt or pointed edges. These may be single or double ended.Plastic filling instruments:cement carriersThey are double-ended having a flat nib with blunt edges on each end, one at 90 degrees to the other.Amalgam carriersHollow cylinder into which the triturated amalgam can be loaded.Condensers Hand or mechanical They are used to compact amalgam, direct gold or composite resins into the prepared cavity. Nibs of condensers may be round, triangular, parallelogram, etcBurnisherssurface of the restoration smooth and shiny.also used to contour metal bands so as to provide the desirable contours for the restoration. The nibs may be ball-shaped, egg-shaped, conical, beaver tail-shaped, etc.CarversCarvers are usually double-ended, binangled instruments with their nibs either beveled or knife edged. The most universally used carvers are the Hollenback carvers, cleoid-discoid carvers, and Frahms carvers. The Hollenback carvers are useful for carving occlusal, proximal and facial or lingual surfaces of amalgam restorations.The cleoid-discoid carvers are double ended. One end is claw-like while the discoid end is disclike in appearance. They are useful to carve the occlusal portions of amalgam restorations.The Frahms carver is also called as the diamond carver as it has diamond-shaped nibs. This is also very useful in carving amalgam restorations.All carvers should have sharp blades and may also be employed for carving inlay wax while fabricating direct or indirect wax patterns for inlays and onlays.FilesFiles are instruments with thin blades that have short teeth on their cutting surfaces. Files are used to trim overhangs of restorative materials like amalgam at the proximal or gingival margins.knivestrimming excess restorative material from various surfaces of teeth. The Bard-Parker knife which has several shapes of blades is most universally.Knives are also used to finish amalgam and direct gold restorations.Finishing and polishing instrumentsFinishing-removal of surface irregularities by a process of cutting and/or grindingPolishing: production of a perfectly smooth and shiny surfacea. Abrasive finishing stripsb. Finishing burs and points c. Brushesd. Mounted rubber.e. Cloth.f. Felt.g. Coated discsAbrasive finishing strips These are hand-held flexible strips of metal or plastic coated on one side with abrasive particles like aluminium oxide, sand, garnet, silicon carbide, etc. They are used for finishing interproximal areas of amalgam or composite restorations by using them in a back and forth motion.Finishing burs & pointsSteel finishing bursamalgam restoration.Carbide finishing burs---composite restoration.Finishing points consist of very fine diamond abrasives--- composite & GIC .Brushes & Mounted rubber Most brushes have synthetic bristles and are used in a contra-angle micromotor handpiece. They may be used alone or with an abrasive paste like prophylactic paste or pumice slurry. Mounted rubber rotary cups, discs, wheels, cones, etc., coated with abrasive particles like silicone carbide or aluminium oxide are used for finishing different restorations like composites, amalgam, cast gold and ceramics. Plain rubber cups are also used with polishing pastes to produce a polished surface.Coated discs Flexible heavy weight paper or mylar strips coated with a suitable abrasive such as sand, silico carbide, aluminium oxide, etc., held by an adhesive material. The discs are attached to a mandrel and used in a handpiece for rotary finishing of restorations.INSTRUMENT GRASPSMODIFIED PEN GRASPINVERTED PEN GRASPPALM AND THUMB GRASPMODIFIED PALM & THUMB GRASPRESTSUsed to steady the hand during operative procedures .SHARPENING HAND INSTRUMENTDull cutting edges causePainProlong timeLess controllableReduce qualityStationary sharpening stoneMechanical SharpenersHandpiece sharpening stonesStationary sharpening stoneThe most frequently used sharpening equipment consists of a block or stick of abrasive material called a ---- stoneCoarseMediumFine gritVarious shapes Flat Grooved Cylindric tapered Four types of materials Arkonsas stonessilicon carbideAluminum oxidediamondArkonsas stoneswhite or gray in color.Hard enough to sharpen steel, but not carbide instruments. Arkansas stones are available in hard and soft varietiessilicon carbide widely used as an industrial abrasive hard enough to cut steel effectively, but not hard enough to sharpen carbide instruments. SiC stones are available coarse and medium grits, but not in fine grits. lubrication with a light oil to prevent cloggingAluminum oxideCoarse and medium grit stones generally appear as speckled tan or brownish in color.Fine grit stones are usually white, have superior properties, and are less porous so that they require less lubrication during use. Diamondonly material capable of sharpening carbide as well as steel instruments.The diamonds are held in place by an electroplated layer of corrosion-resistant metal.Mechanical SharpenersRX HONING MACHINE.More easy.Less timeHandpiece sharpening stonesMounted Aluminum oxide & silicon carbide.PRINCIPLES OF SHARPENINGClean & sterile. Establish proper bevel angle (usually 45) and the desired angle of the cutting edge to the blade before placing the instrument against the stone, and maintain these angles while sharpening.Sharpen with a light stroke or pressure against the stone to reduce frictional heat; use a rest or guide whenever possibleRemove as little metal from the blade as possible, lightly hone the unbeveled side of the blade after sharpening.Remove all metal cuttings from thesharpening stone after use.Resterilize the sharpened instrumentsAdvantagesThey are self limited in cutting enamel they will not cut sound enamel, but cut only enamel undermined by loss of dentin. They can remove large pieces of underminedenamel quickly, thus saving time and effort.No vibration or heat accompanies the cuttingmaking it painless and with no adverseeffects on the tooth tissues.Most efficient means of precise cutting especially when cutting is needed adjacent to important anatomy.Have the longest life span, as Can be resharpened.