Sem 3: notes (Rotary Dental Instruments and Basic Instruments)

Dental Handpieces

  • Driven by compressed air (air turbine) or a micromotor.
  • Types:
    • Contra-angle handpiece
    • Straight handpiece

Air Turbine

  • Speed: 200,000200,000 to 450,000450,000 rpm.
  • Driven by compressed air.
  • Tasks: opening cavities, shaping, removing old fillings, preparing fillings and inlays.
  • Burs: smooth, diamond grit (or sintered carbides).
  • Requires water cooling.

Straight Handpiece

  • Speed: 500−25,000500 - 25,000 rpm.
  • Mounted on a micromotor.
  • Cutters: prosthetic or surgical (ISO 10 coding).
  • Without cooling: Used outside the oral cavity for prosthodontics (denture correction) and orthodontics (removable appliances).
  • With cooling: Used in oral surgery to remove bone and separate teeth.

Contra-Angle Handpiece

  • Types:
    • Universal (Blue): Standard tip 1:1, used in conservative dentistry with carbide burs/brushes, polishing rubbers, abrasive disc mandrels and Arkansas stones (ISO code 20).
    • Accelerating (Red): High-speed, 1:5 acceleration, used in prosthodontics and conservative dentistry with diamond-coated burs (ISO 31).
    • Slow-Speed (Green): Handpieces 4:1, 10:1, 16:1 (reduces speed upon resistance), used in endodontics, oral surgery and prosthodontics with machine endodontic files, brushes, polishing rubbers and surgical burs (ISO 20).

Burs in Dentistry

  • Machine tools mounted on dental handpieces.
  • Parts: shaft, neck, head.
  • Division based on shaft:
    • Straight handpiece: long, smooth shaft.
    • Contra-angle handpiece: shorter, notched shaft.
    • Air turbine: short, thin, smooth shaft.
  • Division based on material:
    • Hardened metal alloys
    • Sintered carbide
    • Diamond grit
  • Applications:
    • Turbine burs: Diamond bits for enamel work and removing fillings, preparing teeth for crowns.
    • Micromotor burs: Sintered carbide for preparing dentin.
    • Straight handpiece burs: Milling cutter for prosthodontics/orthodontics (correcting dentures/appliances), separating roots, cutting bone.
  • Division based on head shape: ball, rose, crevice, flame.

ISO Marking for Burs

  • A - Head material (806-diamond)
  • B - Handle shape (31-turbine, 10-straight, 20-contra-angle)
  • C - Length (4-standard 22mm, 5-surgical 26mm)
  • D - Head shape (3 digits), grit (next 3 digits)
  • E - Head diameter (e.g. 012 - 1.2mm)

Diamond Bur Grit Levels

  • Black - Super coarse (SC) – 181µm181 µm
  • Green - Coarse (C) – 151µm151 µm
  • Blue - Medium (M) – 107−126µm107-126 µm
  • Red - Fine (F) – 40µm40 µm
  • Yellow - Super Fine (SF) – 20µm20 µm
  • White - Ultra Fine (UF) – 15µm15 µm

Dental Lamps

  • Halogen lamps: blue light (390-510nm), intensity 400-950 mW/cm2. Higher intensity = faster polymerization. Soft-start.
  • Plasma lamp: plasma arc, narrow (430-500nm) or broad spectrum (370-510nm), shortens exposure time.
  • Argon laser: narrow spectrum 480-490nm, exposure time may be too short.
  • Diode lamp (LED): light-emitting diodes, low intensity (290 mW/cm2), narrow spectrum 460-490nm, small, infrared-free.

Basic Dental Instruments

  • Dental mirror
  • Dental probe
  • Dental/anatomical forceps
  • Air-water syringe
  • Excavator
  • Flat plastic
  • Ball plugger
  • Dental matrices
  • Metal/plastic spatula
  • Glass plate
  • High-volume suction
  • Saliva ejector

Dental Mirror

  • Construction: handle, mirror (18-20mm, also 22, 24 mm, at 135∘135^\circ to 165∘165^\circ angle), concave mirror.
  • Application: viewing surfaces, illumination, holding/deflecting soft tissues, percussion examination.
  • Types: flat, magnifying, front-surface (rhodium), rear-surface, illuminated, rhodium plated.

Dental Probe

  • Construction: shank, sharp tip (90-135 degrees).
  • Types by tip: straight, obtuse, sickle, claw.
  • Application: palpation, cavity detection, examining smoothness/sensitivity of hard tissues, dentin hardness, filling adhesion, percussion examination.
  • Division by application: endodontic, root caries, universal, periodontal.

Dental/Anatomical Forceps

  • Construction: 2 elastically connected arms, narrow beaks (smooth/grooved), bent at obtuse angle, pin for stabilization.
  • Application: inserting/removing cotton rolls, gripping small instruments.

Air-Water Syringe

  • Element of dental unit; delivers water, compressed air, or mixture.
  • Three-function syringe (or six-function with heating).
  • Application: drying cavities/surfaces, blowing out shavings, cleaning mirror.

Excavator

  • Construction: Shank, sharp working tip (various sizes, flat-cut).
  • Application: manual dentin preparation, removing excess primer/temporary fillings.
  • Types: single/double-sided, left/right.

Flat Plastic

  • Construction: double-sided, spatula/ball ends, steel or titanium nitride coated.
  • Application: applying/shaping fillings, removing excess material.

Ball Plugger

  • Construction: double-sided, smooth ball/pear/cylinder tip.
  • Application: condensing material in defect.

Dental Matrices

  • Compound shape: metal/polyester belt + tensioner (Ivory, Mifam, Nystroma, Tofflemire’a).

Metal/Plastic Spatula

  • Metal: Prepare temporary/root canal filling materials.
  • Plastic: Prepare cements.

Glass Plate

  • Construction: smooth/matte surfaces.
  • Application:
    • Matte: phosphate cement, temporary filling cements.
    • Smooth: silica cements.