PATIENT VISIT 2– FINAL IMPRESSIONS
Laboratory Procedures

Boxing of Final Impression
1. Definitions
    Boxing - Enclosing an impression to produce a base, to preserve the vestibular contours of the final impression, and to create a land area to protect the cast.
    Master cast - A replica of the prepared tooth surfaces (where necessary), residual ridge areas, and/or other parts of the dental arch used to fabricate a dental restoration or prosthesis.
   You may use either the wax, the alginate or the  Play-Doh techniques to box your final complete dentures.  Be sure you are thoroughly familiar with whichever boxing technique you choose to avoid remaking final impressions due to improper boxing.

2. Equipment and materials
a. Wax, beading (red, rod and rope), boxing (red) and baseplate (pink)
b. Knife, Bard Parker No. 6 with sharp No. 25 blade
c. Bunsen burner and matches
d. Wax spatula
e. Plaster spatula
f. Knife, laboratory

Wax Boxing Technique

Maxillary

1. Remove the disinfected impression from the Ziploc bag.  Rinse and dry the impression thoroughly.
2. Flatten a strip of rod wax with your fingers to a thin ribbon shape.  Place it below the trimmed margin of the dried final impression and press it into place.  Wax will not adhere to a wet tray or rubber base.  The wax should extend from the pterygomaxillary notch area of one side to the pterygomaxillary notch area on the other side.  It is not placed on the posterior border.
3. Next, starting at the middle of the posterior border, a strip of red rope wax is placed on the distal of the posterior border.  It is then continued over the flattened wax and around the impression.  The rope wax must not be above the height of the impression along the posterior border.  On the buccal and labial surface it should be 4 mm from the crest of the border of the impression.  The rope wax is then sealed to the impression with a warmed spatula and wax.
4. Attach a strip of boxing wax around the beading wax, starting at the middle of the posterior border.  The beading wax should not be displaced against the border.  Remove excess boxing wax with a heated knife blade.  Gently press the ends together and seal with a heated spatula.
5. Seal any open areas with a hot spatula and wax.  The seal must be complete or stone will leak through when the cast is poured.

Boxing upper impression using wax

Mandibular

1. Remove the disinfected impression from the bag.  Rinse and dry the impression thoroughly.
2. Place the trimmed lower impression on a sheet of pink baseplate wax.  Using a warmed knife, outline the shape of the tongue area in the wax using the impression as a pattern.  Cut out the wax and seal it to the lingual area of the impression tray using a wax spatula.  The wax should be 2-3 mm from the crest of the border of the impression.
3. Next, rod shaped wax is flattened into a ribbon form and pressed into place along the lower margin of the final impression from one retromolar pad area to the other.  A strip of rope wax is placed around the impression over the flattened wax and sealed with a hot wax spatula.  Another strip of rope wax may be needed to obtain the desired thickness of the base to avoid fracture.
4. Firmly attach a strip of boxing wax around the beading wax.  The beading wax should not be displaced against the border.
5. Seal any open areas with a hot spatula and wax.

Boxing lower impression using wax
Play-Doh Technique
 

click here for video

1. Place a ball of Play-Doh  on a flat surface. Create a concavity in the Play-Doh  to accommodate the final impression. Place the final impression into this concavity.

2. Try to seal around the impression using wet finger. About 2-3mm of the impression borders should be visible superior to the Play-Doh and all the tissue surface  should be Play-Doh free. Again use wet finger to smoothen and seal the surface of the Play-Doh.

3. Rap a strip of boxing wax around the Play-Doh. Seal it with hot wax spatula.

The advantages of this technique are its speed and ease of use. 

 Play- Doh

Creating a space for the final impression

Final impression

Boxing using Play Doh