Dental Instruments
Step One: Learning objectives
You will be trained to identify common dental hand instruments and describe their function.
You will describe separate parts of hand instruments.
You will identify common dental rotary instruments and describe their function.
You will describe the parts of handpieces and rotary attachments.
Step Two: Lesson preview
A dental assistant ensures that all instruments are well maintained and sterile.
You need to recognize all instruments.
This lesson introduces hand and rotary dental instruments.
The list is ample, but information is presented in an easy-to-digest manner.
Step Three: Hand instruments
Dentists use a wide variety of hand instruments to perform restorative procedures.
Hand instruments use no electrical power.
During procedures, you pass these instruments to the dentist.
By the time you’re ready to work, dentists will expect you to understand and recognize each one.
Becoming familiar with them starts here.
Common chairside instruments
Most instruments are stainless steel; some are carbon steel, hard plastic, or other materials.
Classified into four categories: examination, tooth prep, restorative, accessory.
Within each class, instruments are identified by instrument numbers and design features.
A manufacturer’s instrument number uniquely identifies a hand tool; stamped on the instrument and in catalogs.
Some dentists refer to pliers and forceps by number rather than name.
You’ll want to become familiar with tool names and numbers for these and other implements.
Design features: all hand instruments consist of three parts: the handle, shank, and working end. These parts appear in images with descriptions.
Handle
The portion you hold.
Some handles are smooth; others have grooves.
Shapes include round or hexagonal.
Grip and smoothness reflect how the operator will hold and use the instrument.
Shank
Connects the handle to the working end.
May be angled to reach specific areas of the mouth.
Its thickness determines how much pressure you can apply without breaking the instrument.
Working end
The part that touches the tooth and performs a function.
Ends can have a point, blade, or nib.
Some hand instruments are double-ended (two working ends).
Black’s formula, angles and dimensions
G. V. Black developed Black’s instrument formula describing the angles and dimensions of a hand instrument’s working end.
Each cutting and scaling instrument shows three numbers identifying blade width, length, and angle.
Quick reference: Black’s instrument numbers in sequence describe:
Width of blade in tenths of millimeters, w (tenths of mm).
Length of blade in millimeters, l (mm).
Angle of blade in degrees, \theta, relative to the handle.
Example values:
Width: w = 10 (tenths of mm) ⇒ 1.0 mm; Length: l = 7 (mm); Angle: \theta = 90^\circ.
Blade angle and function classification
Instruments are also classified by function: cutting vs non-cutting.
Cutting instruments include: angle formers, gingival margin trimmers, chisels, hatchets, excavators, hoes.
Non-cutting instruments include: basic instruments, condensers, burnishers, files, carriers, finishing knives, carvers, plastic filling instruments, composite instruments.
Examination instruments
Mouth mirrors: provide indirect vision; may retract lips, cheeks, and tongue; reflect light into the mouth.
Mirror design: straight handle, slight shank angle, working end with mirror on one side; can be single or double sided; flat or concave; magnifying options.
Mouth explorers: examine tooth surfaces for defects (caries, small fractures, pulp exposures, anomalies); tips are sharp, pointed, thin, and flexible; single or double ended; tip shapes may reflect or shepherd’s hook.
Periodontal probe: measures pocket depth between tooth and gum; deeper pocket may indicate decay or disease; long, thin working end with a blunted tip; calibrated markings on the working end.
Tooth preparation
Tools prepare the tooth for restoration by removing decayed structure, smoothing cavity walls and floors, and placing bevels or retention grooves.
Includes hatchets, hoes, chisels, gingival margin trimmers, angle formers.
Excavator: versatile; removes soft dentin, debris, and decay; used with a push-pull scraping motion.
Hatchet: cleans and smooths cavity walls; removes enamel not supported by dentin; operators push forward with a pushing motion.
Hoe: removes calculus and deposits; straight cutting edge; used with a pulling motion.
Chisels: flatten and split enamel during preparation; bevels used; bevel is an edge with an angle < 90°; straight, Wedelstadt, and Binangle varieties exist.
Gingival margin trimmer: modified chisel with a curved blade; cuts enamel and places bevels along gingival margins; double-ended with one end curving right, the other left.
Angle former: similar to hoe but with cutting edge at an angle other than 90°; forms and defines point angles; downward pushing motion.
Restorative instruments
Amalgam carrier: fills cavities with amalgam; acts like a syringe with tubular tips; double-ended ends carry material; lever releases amalgam into tooth.
Condenser (pack): packs amalgam or other restorative materials into cavity prep; three types:
Smooth condenser (plugger)
Serrated condenser
Interproximal condenser: packs amalgam into interproximal spaces; ends may be smooth or serrated; mesial, middle, distal, or off-center shapes.
Carver: removes excess material and carves anatomical form into restoration before it hardens; four main types:
Carving occlusal anatomy (for chewing surfaces)
Discoid-Cleoid carver (double-ended; one end discoid, one end cleoid)
Hollenback carver (double-ended; ends at different angles)
Half-Hollenback carver (half size)
Burnisher: smooths surface of freshly placed amalgam; rounded working end comes in shapes such as ball, football, acorn, beavertail; football-shaped is common.
Composite instruments: work on composite materials; coated or made from scratch-resistant materials to avoid scratching; placement instruments (often anodized aluminum or Teflon) and burnishers (coated with titanium nitride or gold titanium nitride) for final contouring; coatings provide hard, smooth, nonstick surfaces.
Files: trim excess filling material and smooth margins; various shapes; one side can be rough or serrated; can be single or double-ended; reach interproximal areas.
Finishing knives: trim interproximal material from amalgam restorations; recreate proximal wall contour; can be single or double-ended.
Accessory (miscellaneous) instruments
Spatulas, articulating forceps, scissors, pliers, retainers, paper holders, articulators.
Infection control note: follow proper sterilization or disinfection guidelines before returning items to the cabinet.
Spatulas: cement spatula (single-ended; stainless steel) for mixing liners, base materials, cement; impression spatulas: larger, wider blades; handles may be metal or wood for grip.
Articulating forceps: multi-use; place or remove objects in the oral cavity.
Forceps table (selected examples):
Band or beaks fit into dam clamp holes; provision crown removal (temporary crown removal).
Dental dam forceps are used for specific dam procedures.
Scissors: cut tissue and materials; straight or curved blades; narrow or wide cutting edges; crown and bridge scissors (trim aluminum crowns, temporary crowns, gingival retraction cords, matrix bands).
Tissue scissors and suture scissors: straight or curved; end notches may be present.
Pliers: vary by purpose (bird beak, cotton pliers, grass material handling; serrated tips; used for placing/removing arch wires, cotton products, wedges, matrix bands, etc.).
Matrix retainer: holds the matrix band in place during interdental restorations (e.g., Tofflemire matrix band retainer).
Articulating paper holder: grips articulating paper for bite checks; articulating paper marks occlusal surfaces to assess contacts.
Articulator: mechanical device that imitates mouth and jaw movements; used for mounting dental models and fabricating appliances.
Quick reference: tool categories and sanitary classifications
Critical tools require sterilization between patients: mouth mirror, explorer, periodontal probe, excavator, tooth prep tools (hatchet, chisel, gingival trimmer, angle former), amalgam carrier, condenser, carver, burnisher, composite instruments, spatulas; accessory tools: forceps, scissors.
Sanitary quick reference table (highlights):
Mouth mirror → Examination
Explorer → Examination
Periodontal probe → Examination
Excavator → Tooth prep
Hatchet → Tooth prep
Chisel → Tooth prep
Gingival trimmer → Tooth prep
Angle former → Tooth prep
Amalgam carrier → Restoration
Condenser → Restoration
Carver → Restoration
Burnisher → Restoration
Composite instruments → Restoration
Spatulas → Accessory
Forceps → Accessory
Scissors → Accessory
Step Six: Review practice exercise six to one
1. These use no electrical power. Answer: A) hand instruments.
2. Dental professionals use instruments from this manual category to remove decay. Answer: C) preparation.
3. You’ll find miscellaneous instruments in this category. Answer: D) accessory.
4. This uniquely identifies a hand tool. Answer: Instrument number.
5. All hand instruments have circa three parts. Answer: 3 parts.
6. This part of a hand instrument connects the handle to the working end. Answer: Shank.
7. Its thickness determines how much pressure you can apply. Answer: Shank.
8. The number sequence on a cutting/scaling instrument shows width, length, and angle. Answer: Width, Length, Angle.
9. If width is 5 (tenths of mm), it equals 0.5 mm. Answer: w=5 (tenths of mm) = 0.5 ext{ mm}.
The industry classifies instruments by function to describe their usage. Answer: Function.
These provide indirect vision. Answer: Mouth mirrors.
Used to examine teeth surfaces for defects. Answer: Mouth explorer.
Measures pocket depth. Answer: Periodontal probe.
Removes soft dentin, debris, and decay. Answer: Excavator.
Chisel classification. Answer: Cutting.
Carver classification. Answer: Non-cutting.
Burnisher classification. Answer: Non-cutting.
Hatchet classification. Answer: Cutting.
Hoe classification. Answer: Cutting.
File classification. Answer: Non-cutting.
Condenser classification. Answer: Non-cutting.
Description of a hatchet: cleans and smooths the tooth’s walls in cavity preparation. Answer: Cleaning/smoothing action.
Description of a chisel: flattens and splits enamel in cavity prep. Answer: Flatten and split enamel.
Angle former description: defines the point angles on the tooth. Answer: Defines point angles.
Hoe removes calculus and deposits. Answer: True/Yes (removes deposits).
Double-ended carver with a disc shape and pointed end. Answer: Discoid-Cleoid.
Performs final contouring for pits, fissures, etc. Answer: Composite burnisher.
Emulates a mouth/jaw for modeling. Answer: Articulator.
Pliers to remove retraction cords, wedges, and matrix bands. Answer: Cotton pliers.
Measures pocket depth. Answer: Periodontal probe.
Fills cavities with amalgam. Answer: Amalgam carrier.
Carbon paper used to check bite. Answer: Articulating paper.
Step Seven: Dental rotary instruments
A rotary instrument enables dental professionals to remove or reduce tooth matter and to shake teeth during various procedures.
Burs and polishing tools reflect the primary rotary instruments used.
As a dental assistant, you’ll hand these instruments to the operator and maintain them.
Burr: any rotary instrument with a sharp cutting head made of tiny blades; used to prepare teeth, excavate decay, finish cavity walls and restoration surfaces, drill old restorations, finish crown prep, and adjust temporary crowns.
Burr parts
Shank: connects to handpiece; types include:
Straight shank: long straight shank for straight-line attachment on a low-speed handpiece.
Latch-type shank: small groove at the end to lock into a contra angle attachment on a low-speed handpiece.
Friction grip shank: short, smooth shank held by friction on high-speed handpieces.
Neck: connects shank and head.
Head: cutting, polishing, or finishing portion; comes in different sizes, shapes, and materials.
Bur storage
Bur blocks: polypropylene blocks with holes for shanks; some have magnetized bases; sterilizable in autoclave.
Cutting burs
Have six to eight cutting blades; vary by shape; numbers identify shape/size; dentists may request a bur by number.
Common bur types:
Surgical bur: six blades, flat end; aggressive for gingival walls and amalgam prep.
Diamond bur: very hard; cleaner cuts; finish well; used for ceramics; grit variations affect cutting rate; can lose efficiency after repeated sterilization.
Carbide bur: great for chipping tooth surfaces and removing metal restorations; finishing and trimming composites; preparing teeth for fillings.
330 and 557 are common numbers with specific shapes; 7,901 is a carbide bur; 7,404 is another carbide type.
Finishing burs: used in final polishing; have more blades/flutes than cutting burs.
Fissurotomy burs: small, fast-cutting; recontour fissures with minimal enamel removal; often do not require anesthetic; limited to pits, fissures, and grooves.
Abrasive rotary instruments
Consist of metal shaft, mandrel, and a disc/point/stone/wheel covered with abrasive material.
Abrasive materials:
Silicon carbide: wheels, points, stones; moderately rough for polishing metal restorations.
Garnet: coarse to medium finish for initial finishing stages.
Cuttlebone: used for finishing.
Sandpaper: abrasives on flexible paper disks or strips; moderate abrasion for finishing/polishing.
Carborundum: for cutting or separating structures.
Rubber: used to polish restorations (amalgam, composite, gold).
Abrasive rotary instruments in air
Air abrasive units deliver a controlled stream of abrasive via handpiece nozzle using air and water pressure.
Used for polishing or abrading a tooth; typical abrasive is alpha alumina.
Used to remove decay and prepare pits/fissures for sealants/restorations; often requires minimal anesthesia.
Air-abrasive unit components: device and handpiece; classification: semi-critical.
Step Eight: Tray systems
Tray systems organize and transport instruments to the treatment room; saves time and mental energy.
You place instruments and items on the tray in the order they’ll be used.
Tray options: plastic or metal trays, tubs, or cassette systems.
Color coding and barriers help with handling, storage, and sterilization.
Positioning instruments on the tray:
Place three instruments first on the left: mouth mirror, explorer, and cotton pliers.
Then place remaining instruments left to right by function: examination, hand cutting, restorative, then accessory.
Group related instruments together (e.g., all carvers).
Place cotton supplies along the top; place scissors, hemostats, and hinged instruments on the far right for easy access.
Cleaning and return: keep instruments clean, remove debris with gauze sponges, and return them to their original positions after receiving them from the operator.
Modern storage: trays classified as semi-critical; all items must be sterilized after each patient.
Cassette system
Cassettes carry instruments into the treatment room and then to cleaning/sterilization.
Some instruments are color coded and pre-labeled by procedure names.
Process: open cassette, rearrange instruments for cleaning, close cassette, run through ultrasonic cleaner or instrument washer, rinse, wrap, package, label, sterilize, and store.
Cassettes come in different sizes and can be stored horizontally or vertically.
Color coding helps identify procedure type, treatment room, operator, and sequence; diagonal colors can indicate sequence.
Step Eleven: Practice exercise 6-2
A rotary instrument enables dental health professionals to do this: Shape teeth. (Answer: A)
All rotary instruments with a sharp cutting head are called: burs. (Answer: B or C depending on the specific prompt; the material uses “c burs” for this item.)
Shank with a small groove to lock into a contra angle on a low-speed handpiece: latch type. (Answer: C)
Narrow portion connecting the shank and the head: neck. (Answer: C)
It is made of plastic and holds burs: burr block. (Answer: B)
A fissurotomy bur is used for rapid cutting to recontour pits/fissures with minimal enamel removal. (Answer: D)
A finishing bur is used in the final stage of polishing. (Answer: C)
A diamond bur is very hard with excellent cutting ability. (Answer: B)
A cutting bur is described as having six to eight cutting blades. (Answer: A)
Identify the bur numbers from images: 7,901, 557, 330, etc. (Answers reflect the provided references: 7,901; 557; 330; diamond bur; etc.)
The bur types and their typical uses were reviewed, including: surgical bur, carbide bur, diamond bur, fissurotomy bur, finishing bur, laboratory bur, and surgical burs.
Common shapes for abrasive rotary instruments include: disc, point, stone, wheel. (Answer: four shapes)
Surgical burs or root canal files are used in endodontic procedures (root canal).
Store burrs in a burr block when not in use; keep blocks sterilized.
Where to store burrs: burr blocks.
Repeated sterilization can diminish the cutting efficiency of diamond burs due to loss of diamond flakes.
In an endodontic context, surgical burs are used to clean and enlarge canal walls during root canal procedures.
Step Eleven: Additional practice prompts (summary cross-check)
General checks like identifying tool categories, sequence on the tray, and color-coding logic are reinforced in practice exercises.
Step Twelve: Why this matters
As a dental assistant, you handle many tools and must pass them to the dentist quickly, prudently, and organized.
Familiarity with instruments prevents delays, reduces patient wait times, and upholds professionalism.
This lesson divided tools into manual and rotary instruments, with images and explanations for clear recognition.
Rotary instruments are powerful and require proper handling and maintenance.
Summary
Manual instruments (unmotorized) fall into four categories: examination, tooth prep, restorative, and accessory; all are classified as critical and require sterilization.
Black’s formula provides the angles and dimensions of working ends: three numbers (width, length, angle).
The lesson covered categories and specific instruments within each, with practice opportunities to view, review, and recognize tool functions.
Rotary instruments (bur heads, abrasive tools) are used to shape, cut, polish, and contour both teeth and restorative materials; proper storage and sterilization are emphasized.
Storage and organization (tray systems and cassette systems) help ensure efficiency, infection control, and clear workflow in the treatment room.
Endnotes
Journal entry prompts:
Compare different types of rotary instruments (e.g., dental burs, diamond discs, polishing cups) in terms of design, shape, size, and task suitability.
Reflect on hand instrument shafts (straight, contra-angled, right-angled) and how shaft design influences task performance.
Consider why recognizing and understanding each hand instrument is essential for a dental assistant’s professionalism and efficiency.
Journal prompts (optional)
How do instrument design features influence ease of use and patient comfort?
How can you improve instrument recognition before clinical practice?