IDENTIFICATION OF OPERATIVE INSTRUMENTS

ecause  of  the  many  hard  to  reach  areas  in  the human   mouth   and   various   functions   required, operative instruments come in a wide variety of sizes and  shapes.  To  be  an  effective  dental  assistant,  you must be able to understand why, where, and when the dentist  will  use  them.  We  will  discuss  hand  cutting instruments,  amalgam  instruments  that  consist  of condensers,  carvers    and  burnishers,  and  composite (resin) instruments. HAND  CUTTING  INSTRUMENTS Many  dental  procedures  require  the  use  of  hand instruments  with  sharp  cutting  edges.  This  cutting instrument group used in operative dentistry includes excavators,   chisels,   hatchets,   hoes,   and   gingival margin   trimmers.   They  are  used  in  the  cavity preparation  of  both  amalgam  and  composite  (resin) restorations. Spoon  Excavators The spoon excavator is a double-ended instrument with   a   spoon,   claw,   or   disk-shaped   blade.   Spoon excavators  are  used  primarily  to  remove  debris  from tooth  cavities.  Their  tips  and  sides  are  designed  for cutting action. The most common sizes are the small and the large (fig. 4-1) spoon extractors. Chisels Dental  chisels  are  commonly  referred  to  as miniature  chisels.  Chisels  are  used  to  cleave  (split) tooth enamel, to smooth cavity walls, and to sharpen cavity preparations. The two most common types used in operative dentistry are the Wedelstaedt and biangle chisels   (fig.   4-2).   The   Wedelstaedts   have   slightly curved shanks and are used primarily on anterior teeth. The biangle chisels have two distinct angles—one at the  shank,  and  one  at  the  working  end.  This  design allows  access  to  tooth  structures  that  would  not  be possible with straight chisels. Hatchets A  dental  hatchet  (fig.  4-3)  resembles  a  camper's hatchet,  except  much  smaller.  Like  dental  chisels, some have single cutting ends, and others have cutting edges on both ends of the handle. Hatchet blades are set

Back Chapter 4 Operative Dentistry Up Dental Technican, Volume 2 - Dentist training manual for military dentists Next AMALGAM  CARRIERS Figure 4-1.—Small and large spoon excavators. Figure  4-2.—Wedelstaedt  and  biangle  chisels. Figure 4-3.—Hatchet. at  a  45-  to  90-degree  angle  from  the  shank.  These instruments  have  different  lengths  and  widths  of blades.  Hatchets  are  used  on  the  wall  of  the  cavity preparation  to  cleave  enamel  and  cut  dentin  so  there will be a sharp cavity outline. Hoes Dental hoes (fig. 4-4) look like a miniature garden hoe. They are used with a pulling motion to smooth and shape the floor and sides of cavity preparations. Hoe blades  are  set  at  a  45-  to  90-degree  angle  from  their handle. Gingival Margin Trimmers (GMTs) The  gingival  margin  trimmers  (GMTs)  (fig.  4-5) are  modified  hatchets  that  have  working  ends  with opposite curvatures and bevels. As the name implies, GMTs are used to trim, smooth, and shape the gingival floor  of  a  cavity  preparation.  GMTs  are  available  in double-ended styles and are used in pairs, such as the #26 and #27. This is because the working ends of the even-numbered  instruments  are  designed  for  use  on the distal surfaces, and the odd numbered are used on the mesial surfaces. AMALGAM  RESTORATION INSTRUMENTS The instruments discussed in this section are used when  the  dentist  elects  to  use  an  amalgam  or  a temporary dental material to restore a tooth. 4-2 d   Figure 4-4.—Hoe. Figure 4-5.—Gingival margin trimmers (GMTs). Condensing Instruments To deliver the amalgam to the cavity preparation and properly condense (pack) it, the dentist will use a variety  of  instruments. Amalgam   carriers   and condensers are used for this purpose. completed, eject any remaining a: nalgam alloy from the  carrier  into  the  amalgam  well  The  carrier  is  no longer  serviceable  when  the  amalgam  is  allowed  to harden in the carrier. CONDENSERS. —Amalgam   condensers,   often called  pluggers, are instruments used to condense or AMALGAM  CARRIERS.—Amalgam carriers (fig.   4-6)   transport   the   freshly   prepared   amalgam restorative  material  to  the  cavity  preparation.  These carriers have hollow working ends, called barrels, into which the amalgam is packed for transportation. Both single and double-ended carriers are available with a variety   of   barrel   sizes   including:   mini,   large,   and jumbo.  When  the  lever  (located  on  the  top  of  the carrier) is depressed, the amalgam is ejected into the cavity  preparation.  Normally,  two  carriers  are  used during the amalgam placement procedure. This saves time  for  the  dentist  who  is  ejecting  or  condensing  a carrier  load  while  you  are  refilling  the  carriers.  A poorly packed carrier of amalgam handed to the dentist may  fall  out  before  it  is  ejected  into  the  cavity preparation. It is your responsibility to ensure that all carriers are properly packed before the transfer to the dentist.  After  amalgam  material  placement  is pack  the  amalgam  filling  materials  into  the  cavity preparation.  The  hammer-like  working  end  is  large enough to compress the soft amalgam without sinking into it. Condensers come in single- and double-ended designs. They have various shaped and sized working ends,  which  may  be  smooth  or  serrated  as  shown  in figure 4-7. Carvers After the amalgam is condensed, it must then be carved  to  approximately  the  same  original  tooth structure.  Carvers  have  sharp  cutting  edges  that  are used to shape, form, or cut tooth anatomy into amalgam restorations. Figure 4-8 illustrates these instruments that come  in  assorted  shapes  and  sizes  in  double-ended designs.   Many   carvers   were   designed   for   carving specific  tooth  surfaces.  The  Interproximal  and  #1/2 Hollenback  were  designed  for  carving  proximal  (in between) tooth surfaces; whereas, the discoid-cleoid # 89/92  and  Tanner  #5  are  used  on  occlusal  surfaces. Carvers shaped similar to Vignon or Frahm #2/3 (also  Figure 4-6.—Amalgam carriers. Figure 4-7.—Amalgam condensers. called  acorn  carvers)  are  used  to  quickly  carve  the basic  anatomy  on  occlusal  surfaces.  As  with condensers,  dentists  also  have  favorite  carvers  that they  use  routinely.  You  must  know  the  dentist's preference so that you can have the desired instrument ready when it is needed. Burnishers When the carving is complete, the dentist may use burnishers to smooth and polish the restoration, and to remove  scratches  left  on  the  amalgam  surface  by  a carving instrument. Burnishers have smooth rounded