Hand Instruments for Manipulation of Restorative Materials

Hand Instruments for Manipulation of Restorative Materials

General Classification of Operative Instruments

  • Cutting instruments
  • Condensing instruments
    • Hand
    • Mechanical
  • Plastic instruments
    • Spatulas
    • Carvers
    • Burnishers

Lecture Outline

  • Instruments used for manipulation of:
    • Amalgam
    • Direct tooth-colored restorative materials
  • Instrument grasps
  • Sharpening of hand instruments
  • Advantages of hand instruments

Gold Foil

  • Cohesive gold was used by Arabs in the later 18th century.
  • Considered the best with excellent clinical characteristics.
  • Requires high clinical skill and is time-consuming.
  • Special condensers are needed, e.g., set of Loma Linda.

Amalgam

  • Used more than any other restorative material.
  • Relatively simple technique.
  • Clinical characteristics offer good service ability and durability.
  • Prepared by mixing alloy with mercury through amalgamation or trituration.
  • The produced plastic (soft) mass is packed or condensed into the prepared cavity where it hardens.

Instruments for Amalgam Placement, Condensing, and Carving

  1. Carrier
  2. Condenser
  3. Carver
  4. Burnisher
1- Amalgam Carrier (GUN)
  • Working end:
    • Spring-loaded barrel with a central plunger (finger level push).
    • May be single or double-ended.
    • Angled relative to the long axis of the handle for improved access.
    • May have a bi-angled design.
  • Used to load amalgam into the cavity.
2- Amalgam Condensers
  • Hammer-like working end.
  • Double-ended.
  • Shank is usually bi-angled.
  • Nib face:
    • Smooth or serrated.
    • Smooth tends to slip.
    • Serrated prevents slipping during condensation.
    • Serrated face tends to clog up with amalgam and must be cleaned immediately after use.
  • Many shapes and sizes are available.
  • Shape should be selected to fit within the outline form of the cavity: round, elliptic, triangular, trapezoidal, and rectangular.
  • Size is important depending on the cavity.
  • Objective of condensation:
    • Adapt amalgam intimately to the prepared walls & margin.
    • Compact amalgam to produce uniform mass.
Mechanical Condensers
  • Grouped into vibratory types.
  • Caution should be taken when working near margins to avoid breakage.
  • Not superior to manual ones.
3- Amalgam Carver
  • Double-ended hand instrument with a sharp blade.
  • Two blades may not have identical shapes on the same instrument.
  • Blades are set at right angles to each other to improve access.
  • Shanks are usually contra-angled.
  • Several types are available, but the commonly used are:
    • Cleoid-Diacoid Carver
    • Hollenback Carver
    • Ward’s Carver
A. Cleoid-Diacoid Carver
  • Working ends comprise two sharp blades.
  • The discoid is useful for removing gross excess at the initial stage of carving an amalgam restoration.
  • The cleoid end is used for defining anatomical grooves and pits.
B. Hollenback Carver
  • Has elliptical blades with sharp or pointed tips set at right angles to each other.
  • Available in two sizes: standard Hollenback and the smaller 1/2.
  • Versatile and can be used to carve most aspects or surfaces of the restoration.
C. Ward’s Carver
  • Two types are available: Ward 1 and 2.
  • In Ward No. 1, one shank is mono-angled, and the other is bi-angled.
  • The blades are identical.
  • Ward’s Carver is usually used to carve amalgam & wax.
  • Ward No. 2 is very similar to a Hollenback carver except that the end of one of the blades is rounded rather than pointed.
4- Burnisher
  • The working end consists of smooth surfaced nibs of various sizes and shapes.
  • Examples: tail-ended, egg, conical burnishers, beaver-tail.
  • Generally, a burnisher is double-ended with two different nib shapes on each instrument.
  • Used for adapting, compacting amalgam to the cavity walls and margins.
  • Improves the surface quality of amalgam.
  • Makes the surface shiny by rubbing.

Tooth-Colored Restorations

  • Since early in dentistry, matching tooth color with a restorative material has been of concern.
  • Many materials are available nowadays (composite resin, glass-ionomer, compomer).
  • None are ideal but have advantages and limitations.
Plastic Filling Instrument (PFI)
  • Double-ended instrument with a bi-angled shank.
  • Used to manipulate materials in a soft state.
  • Used to carry and place various cements and composite resin in a tooth cavity.
  • Some have flat blades, others rounded.
Flat Plastic Instrument
  • Generally made of stainless steel.
  • Non-stick hard plastics are available, which are useful as the adhesion of cements and composite resin is minimal, thus preventing the restorative material from being dragged from the tooth upon removal of the instrument.
  • Recently, titanium nitride instruments prevent stickiness of composite.
Cement Spatula
  • Either double or single-ended hand instrument with a straight shank.
  • The working end consists of a flat wide blade.
  • Used for mixing various cements on a glass slab or paper pad.
  • Plastic or agate spatula is preferred over metal to minimize possible contamination of the mix from a braded metal.

Hand Instrument Grasps

  • Precise instrument control is important during operation procedures.
  • Hand slips while operating may gouge the gingiva and result in a lack of confidence by the patient.
  • Control is the basic issue and essential for a good operator.
  • To achieve control against unwanted movement, the dentist with his hands and body must provide rigidity and bracing.
  • Correct dental instrument grasps must be learned before bad habits are formed.
Basic Instrument Grasps
1) Pen Grasp
  • More flexibility of movement but less power.
  • Used when an up and down, chopping motion with action is the wrist.
  • The most frequently used in operative procedure.
  • Dental instrument should not be grasped as a writing pen.
  • The shaft is engaged by the end of the middle finger to be more secure and provides the operator with more finger power in its usage.
  • The ring finger serves as a brace against the teeth to permit chopping action.
  • Possibility of slippage of ring finger if teeth are wet.
  • Precaution measure and dry field.
2) Modified Pen Grasps
  • Used when a rotating motion is taking place in the forearm instead of the wrist.
  • Difficult to learn, but very effective when mastered.
  • Difference between it and pen grasp: The angle formed by the shaft of the instrument and the long axis of the forearm (90º90º).
Inverted Pen Grasp
  • Same as pen grasp except that hand rotated so that palm faces toward the operator.
  • Commonly used for preparing lingual aspect of maxillary anterior teeth.
3) Palm and Thumb Grasp
  • Provides limited movement with controlled power.
  • Instrument is grasped very near to its working end.
  • The thumb can be braced against the teeth so as to provide control during instrument movements.
  • The instrument is grasped with the thumb serving as a brace.
  • This grasp is the same as holding the knife for peeling the skin of an apple.
  • This grasp has limited use only while operating on maxillary anterior teeth.
4) Modified Palm Grasp
  • Should be learned after the palm grasp has been mastered.
  • The tip of the thumb rests on the tooth being prepared or the adjacent tooth.
  • Provides more control to avoid slipping of instrument.
  • This grasp is commonly used in maxillary anterior teeth.
Rules
  • Bracing with the thumb or fingers always whenever cutting is applied.
  • Bracing always be moved as close to the contact point.
  • Selection and application of grasp depend on:
    • Position of the operator
    • Quadrant being operated
    • Specific procedure

Advantages of Hand Cutting Instruments

  • Self-limited in cutting enamel.
  • They can remove large pieces of undermined enamel.
  • Create a smooth surface on cutting.
  • No vibration or heat.
  • Long lifespan and can be sharpened.

Sharpening Hand Instruments

  • Goals:
    • Instrument must be kept sharp.
    • Maintain life of instrument
    • Maintain the contour (shape) of instrument
  • Advantages of using well-sharpened instruments:
    • Less pressure, force, and treatment time
    • Minimized patient discomfort
    • Improved efficiency, tactile sensation, and instrument control.
How to Recognize Sharpness?
  • If the cutting edge digs in during an attempt to slide the instrument forward over the surface, the instrument is sharp.
  • Magnifying loupes are useful in evaluating the condition of the cutting edge.
What to Use?
I. Hand Sharpening Stone
  • Arkansas stone
II. Motorized Grinder
  • Arkansas wheel
  • Wax impregnated wheel
    • No oil, polishing compound to reduce heat
  • Slot guide
  • Oscillating sharpener
Principles
  • The instrument should be clean and sterile before sharpening.
  • Establish & maintain proper angle between stone and instrument.
  • Lubricate the stone during sharpening to reduce clogging & heat.
  • A stable and firm grip of both instrument and stone is required.
  • Apply light stroke or pressure.
  • When sharpening is completed, observe the cutting edge (4-5 scrapes, blade end only sharpened).
Disadvantages of Hand Sharpening Stone
  • Difficult to maintain precision and uniformity.
  • A small diameter stone reduces the quality and accuracy of edges (inexperienced operator).
II. Motorized Grinder
  • Rotary-type consist of:
  • Advantages:
    • Instrument sharpened
    • Minute loss in the blade
  • Disadvantages:
    • Sustained contact against the wheel:
      • Reduce blade length
      • Generate heat
      • Shorten the working life of the instrument