A custom made device prepared for a particular patient which is used to confine and control an impression material making an impression. It makes on the cast obtained from primary impression. It is used for making final impression. Edentulous ridge shows variations in shape and size. It shows the type of impression technique 1, Selective pressure technique 2, Minimal pressure technique

1. CUSTOM TRAY FABRICATION AND
MATERIALS
DR MUHAMMAD JUNAID AJMAL KHAN
BSC , BDS , RDS , FCPS (R)
PROSTHODONTIC DEPARTMENT

2. INTRODUCTION
 A custom made device prepared for a particular patient which is used to confine
and control an impression material making an impression.
 It makes on the cast obtained from primary impression.
 It is used for making final impression.
 Edentulous ridge shows variations in shape and size.
 It shows the type of impression technique
1, Selective pressure technique
2, Minimal pressure technique

3. OBJECTIVE
 To fabricate individualized final impression trays as an aid to:
1, Correct coverage of the ridge
2, Development of the border seal
3, Even distribution of the final impression

4. MATERIALS AND EQUIPMENTS
 Diagnostic cast
 Base plate wax
 Self cure acrylic resin
 Mixing jar(porcelain jar)
 Vaseline
 Red and Blue pencil
 Sharp Knife
 Plastic spatula
 Acrylic Burs

5.  Cellophane
 Wet pumice
 Glass Slab/ Roller
 Cutter Tray Frame

6. IDEAL REQUIREMENTS OF CUSTOM TRAY
 It should be dimensionally stable
 It should be strong and rigid
 It should be easy to construct
 It should be inexpensive
 It should be easy to trim in the clinic
 Handle should not interfere with border molding
 Smooth margins
 Allow adhesion to final impression

7.  Posterior limit should slightly overextended to inclusion of posterior detail

8. ADVANTAGES OF SPECIAL TRAY
 Less impression material is required
 More accurate impression
 It provide even thickness of impression material
 Easier and quicker work
 More accurately adapted to the oral vestibules
 Less bulky

9. PROCEDURE
 OUTLINING THE CAST:
(MAXILLARY)
1, Using blue pencil, outline the depth of fold,
extend from hamular notch to hamular notch,2mm
posterior to the fovea.
2, Using red pencil, draw a line 2mm short to the
mucobuccal fold, interior to blue line, provide
room for the frenum attachments, extend from hamular
notch to hamular notch, coinciding with blue line.

10.  (MANDIBULAR):
1, Using blue pencil, ouline the depth of fold.
2, Using red pencil, draw a line 2mm short to the
mucobuccal fold, interior to blue line (start at retromolar
pad, outline distal extent of pad, carry lateral end to the
external oblique ridge, follow ridge to about 2nd bicuspid
area).
3, Leave adequate room for frenum.
4, Lingually tray is 2mm short to floor of mouth
5, Distal-lingual border is obtained by dropping line from distal of
retromolar pad perpendicular to floor of mouth

11. TYPES OF TRAY
 Spaced special tray:
1, Stopper
2, Without stopper
 Closed fit tray:

12. FABRICATION OF A SPECIAL TRAY
 The cast should be soaked in water for 5 minutes.
 Severe undercuts should be blocked out using wax.
 The border of the special tray and relief areas should be marked.
 The borders of the tray marked on the cast are grooved deeper using carver, this
act as guide to trim the tray later.

13. For close fit special tray
 Application of separating medium on study
cast.
 Using the cold cure acrylic tray material by
either dough or sprinkle on technique.
For spaced special tray
 Adapting the wax spacer should be about 2
mm thick, posterior palatal seal area is not
covered with spacer on cast.
 Stopper
 Application of separating medium on the
spacer and stopper areas.
 Using cold cure acrylic material by either
dough or sprinkle on technique.
 When special tray is removed from the cast,
wax spacer is left inside the tray to proper
positioned in the mouth during border
molding procedure.

14. TRAY FABRICATION TECHNIQUE FROM
DENTURE
 Select a container slightly wider than the denture.
 Mix sufficient alginate to fill half the container.
 Wipe onto the undersurface of the denture taking care, not to trap bubbles.
 Seat the denture into the alginate and cover 2-3 mm of the extension with the
material.
 Remove the denture from the alginate after the material has set.
 Inspect the alginate impression. There should be no voids or bubbles and the
denture extension should be defined.
 Using alternate application of powder and liquid and build up the contour and
thickness of the tray.
 Finish the tray and smooth the borders

15. WAX SPACERS AND RELIEF
 RELIEF:
1, Reduction of undesirable pressure from a specific region under a
denture base.
2, The creation of space in an impression tray for the impression material.
 RELIEF AREAS:
There are certain areas of the denture foundation, which do not
tolerate undue pressure from the denture.

16. (Maxilla):
1, Incisive papilla
2, Mid palatine raphe
3, hard sharp bony areas on the ridge
4, Tori and bony prominence crestal to undercut area
5, Labial undercut on anterior and slight buccal undercut in bicuspid region
(Mandible):
1, Mental foramen
2, Crest of alveolar ridge
3, Torus mandibularis
4, Labial undercut
5, Retromylohyoid areas

17. PROCEDURE TO PROVIDE RELIEF
 Relieving the impression tray:
We can record these areas with minimal pressure. By two
ways.
1, Wax spacer
2, Relieving the tray
 Relieving the denture base:
A thin layer of metallic foil is adapted onto the master cast
over the areas needing relief just before acrylization. After denture
processed, the foil is removed.
 Some operators recorded entire denture bearing areas with minimal pressure or selective /
minimal pressure.

18. TYPES OF TRAYS
 Acrylic custom tray
 Vacuum- formed tray
 Visible light cure tray
 Shellac custom tray

19. ACRYLIC CUSTOM TRAY
 The acrylic available as tray material is specially formulated type. It has a higher
filler content, so it less sticky and more moldable
 Separating media is applied and allowed to dry.
 Types:
1, heat cure
2, self cure

20. METHODS OF ADAPTATION
 Direct adaptation:
1, powder liquid is mixed according to instruction
2, hand, cast and glass slab should be coated with Vaseline
3, when it reaches the dough stage, it is removed and kneaded.
4, Material shaped into a 2 mm thick sheet by either 2 glass slab/
plastic roll.
5, In maxilla, it is in the shape of flat ball, adapt it first in the palate, over the ridge
and into the fold areas. In mandible, it adapt on bench top, on side of arch first and
spread into place over remaining portion on the arch and folded portion.
6, Excess material can be shaped into a tray handle.
7, place cast with resin tray into curing oven for 5 minutes and without curing, keep
tray on model for 24 hours for maximum polymerization.
8, Remove the tray, trimming and finishing the tray according to the marking on cast.

22.  Using molds:
1, Tray forming mold can be made from dental stone.
2, The mold is lubricated with petroleum jelly.
3, Mix acrylic is packed.
4, The surface may be smoothened with a lubricated roller.
5, After it has reached sufficient consistency, it is removed and
adapted onto the cast.
6, It provide more uniform thickness.

24.  Sprinkle-on technique:
1, The powder and liquid are loaded in separate dispensers.
2, Small quantity of powder and liquid is sprinkled on particular
area over the cast (associated landmarks are covered) in
alternate layers till relative thickness is achieved.
3, liquid polymerizes the powder
4, Roughen the ridge area on the top of the tray anteriorly at the
midline, to make the handle

26.  Advantages:
1, Ease of use
2, Minimal wastage of material
 used:
It is used for individualized impression tray

27. VACUUM-ON FORMED TRAYS
 Thermoplastic sheets are commercially available.
 These are placed in the machine and softened.
 It is lowered over the cast and vaccum machine is switched on.
 Vaccum created pulls and adapts softened sheet onto the cast.
 Asbestos used as a relief material.

28. VISIBLE LIGHT CURE TRAYS
 Visible light cure material is readily adapted and shaped manually with wet
fingers.
 The excess material trimmed with knife.
 After tray has been completed formed, it is light cured in a curing unit or chamber.

29. SHELLAC CUSTOM TRAYS
 It is still commonly used, in spite of drawbacks.
 Drawbacks:
1, They are relatively weak.
2, They are relatively unstable dimensionally.
 Strengthening of trays:
1, Tray need to reinforced in order to reduce distortion and
improve strength.
2, In maxilla, stainless steel wire is adapted across the palatal seal
area .
3, In mandibular, wire is adapted across the lingual flange.
 Wire are secured by adapting a layer of compond/self cured acrylic.
 Handle are made with compound/ self cured acrylic resin.

30. TRIMMING THE TRAY
 Maxillary tray:
It is trimmed 2-3 mm short of the reflection all around and
should extend up to and include posterior vibrating line posteriorly.
 Mandibular tray:
It is also trimmed 2-3 mm short of the reflection all around except
posterior region, it should include retromolar pad area.
 Borders:
It should be smoothed and polished to avoid rough edges.
 The tray is ready for trial in the patient mouth.

31. SPECIAL TRAY HANDLES
 Handle designed in a wide variety of ways.
 It is commonly made from excess material.
 It is placed onto the front the tray in the shape to the length, width and inclination of 2
central incisors. It should be positioned just lingual to the crest of the ridge in the midline.
 Blend the resin, to make it smooth and wrinkle free and flatten top of handle.
 REQUIREMENTS:
1, They should be easy to grasp.
2, They should not interfere with border moulding maneuvers.

32. PROBLEMS AND ERRORS
 INCORRECT OUTLINED MODEL:
it will result in overextended or underextended
 EXCESSIVELY THICK TRAYS:
it require much mechanical reduction and polishing at the chairside.
 THIN TRAY:
it weak and distort in the final impression procedure, it may also break.
 INCORRECTLY DESIGNED TRAY HANDLES:
it will prevent proper manipulation of the lip and
interfere with accurate impression procedures.
 IMPERFECTION ON THE INTERNAL SURFACE OF THE TRAY:
it will result in inaccurate cast.

33. REFERENCE
 JHON J. MANAPPALLIL :complete denture prosthetic;(ed 13),2013 pp115-119.
 Bernard Levin, Glenn D Richardson :complete denture prosthodontics;(ed 17)
,2002 pp31-33.
 Faryal Saeed Abdal, Prof Dr Sajid Naeem :abdal,s manuals of dentistry;(ed
1),2016pp52-54.
 Dr. Azad Almuthaffer :complete denture prosthodontics;(ed 2)2016pp33-40.

34. THANK YOU