laboratory.   If   you   do   not   know   these   procedures, patient cases can be lost or routed improperly. If you have any questions about different procedures, ask the dentist or prosthetic technician. CASE  REQUESTS Cases  entering  the  laboratory  are  required  to  be accompanied  with  a  work  authorization  request  (DD Form  2322).  Requests  are  to  be  filled  out  with instructions, signed by the requesting doctor, and must indicate  desired  completion  date.  The  case  is  then entered  into  the  Prosthetic  Log  and  assigned  a  case number.  This  entry  must  be  made  by  the  person delivering the case to the laboratory. IMPRESSIONS Before  entering  the  laboratory  ALL  impressions are  to  be  sprayed  with  an  approved  disinfectant  in accordance  with  BUMEDINST.  6610.10,  chapter  6, and covered with a plastic wrap (head rest covers work great). The laboratory technician is to be informed of the arrival of the impressions. Alginate   Impressions Alginate impressions are to be placed into the tray holder at the plaster bench to prevent distortion of the impression (a moist paper towel should be placed over the  impression  to  prevent  dehydration  of  the  material). Final  Impressions This  includes  complete  dentures,  removable partial   dentures,   crowns,   and   bridges.   These impressions are poured as prescribed by the doctor; if no instructions are provided, they will be poured with stone mixed with liquid stone hardener. Study Casts Study casts are fabricated for diagnostic purposes and  poured  as  prescribed  by  the  doctor.  If  no instructions  are  provided,  they  will  be  poured  in plaster. STONE OR PLASTER CASTS Trim  the  casts  once  they  are  separated  from  the tray. Casts are trimmed to remove excess material by use of the model trimmer. You  are  required  to  don  protective  ear  and eyewear. Turn on water supply to desired flow. Activate the model trimmer. Trimmed  casts  will  be  rinsed,  dried,  and  marked with the patient's last name and case number (if space is available). The case will then be routed according to the work authorization request. CASES WHILE IN THE LABORATORY Casts will be kept in case pans, protected in plastic (when   available).   Case   pans   will   be   labeled   with patient's   name,   doctor,   date   started,   and   prothesis being fabricated. Pumice   and   polishing   procedures   for   the fabrication  of  new  protheses  will  not  require  special precatutions. Repairs, relines, rebases, or adjustments of  any  prosthesis  that  has  had  contact  with  patient's body fluids are considered old cases and will require precautions.  Lathe  instructions  for  pumice  and polishing are as follows: The  technician  is  required  to  ensure  correct placement of the protective shield is in the down position before activating the lathe. Pumice is to be replaced after each use. Wheels/brushes used for pumice and polishing are  to  be  removed  from  machine  and  sent  to CSR. Prostheses should be put into a glass beaker or ziplock bag containing cleaning solution, then placed  into  ultrasonic. Ultrasonic Cleaner The prosthetic ultrasonic cleaning machine is the same as the CSRs except that dental prostheses are run through. The following are guidelines for its use: Ultrasonic to contain water approximately 1 to 1-1/2  inches.  Special  solutions  to  be  used  in ziplock bags or glass beakers. General-purpose  cleaner  or  stone  and  plaster remover solutions can be reused when used on new cases. Once solution is used for an old case, the solution is to be discarded. Stain and tarter solution is used for old cases and will be used one time then discarded. Once  the  ultrasonic  cleaning  procedure  is completed,  the  prosthesis  is  then  brushed  and  rinsed with  water.  It  is  then  bagged  and  replaced  into  the assigned case pan. 8-34