Chapter 2- Impression taking and die preparation
Instructor of The Nippon Dental University College at Tokyo
Yoshio Yamaguchi
Director of KEN. DENTALX Co. Ltd.
Kenji Matsuura
I.

Method of impression taking to the fabrication of die for one-piece typeThe impression taking technique for AQB one-piece implant is the same as that for the natural teeth
therefore it is a relatively simple procedure. There are instances such as in some combinations ofimplants with certain diameters or the length of abutment or the parallel nature of the implant bodywhereby preventative measures for fracture of the abutment is necessary.
[Agar alginate combined impression]①

Take impression after establishing a firm interaction between the implant and the bone (usuallyafter two to three months) (Fig. 4-2-1 to 4).

②

Select a tray with a size so that the sides of the trays do not contact the implant body (Fig. 4-2-5).

③

The agar impression agent should be applied mainly to the abutment surroundings (Fig. 4-2-6).

④

Complete the impression taking (Fig. 4-2-7).

⑤

Modeling material
1. In modeling material selection for the implant superstructure, the important factors are thehardness and its dimensional stability.
2. If the blood is smeared on the impression material, rinse and disinfect before application of plaster(Fig. 4-2-9).

⑥The floor of the working model should be constructed with the same modeling material for the finish(Fig. 4-2-10).

Fig. 4-2-1 Implant AQB one-piece

Fig. 4-2-2 Single implant casetype to the left maxillary first molar

Fig. 4-2-3 Antagonist teeth

Fig. 4-2-4 Occlusal relationshipFig. 4-2-5 Impression tray

Fig. 4-2-6 Injection of agar impression
material (Aromaloid, GC Co.)

Fig. 4-2-7 Alginate impression

Fig. 4-2-8 Fabrication of die, super hardmaterial (Aroma Fine DF, Normal set,plaster (Fujirock GC) was used.

GC Co.)

Measure to prevent abutment fracture.

Fig. 4-2-9 Differentiate the use of hard

Fig. 4-2-10 Use the same modelingplaster for instances when substancesmaterial for the floor to achieve as much

such as blood becomes smeared on thedimensional stability as possible.

impression agent (New Plastone, GCCo.)
II. Method of impression taking to the fabrication of die for one-piece T-type
The method is generally the same as that for the one-piece type, but here the rubber based impression
agent is used to prevent the abutment fracture.
[Impression technique with rubber based agent]① Take the impression with the impression tray (Fig. 4-1-15)② Construct a working model with hard plaster (Fig. 4-2-16)③ Forming individual tray for abutment impression and custom tray
1. The outline of the individual tray should be recorded (Fig. 4-2-17).
2. The thickness of the impression material is evened out by forming wax relief on the cast, andapplying room temperature curing resin (Fig. 4-2-18).

3. Form impression by compressing the resin on the impression tray with the usual procedures (Fig.
4-2-19).
4. Once the tray resin has set, relieve the internal stress by dipping the tray into warm and cold
water in alternating manner (Fig. 4-1-20).
④ For silicon rubber impressions, employ impression agent with a high viscosity. The abutment is at
higher risk of fracturing with a small degree of elasticity (Fig. 4-2-21 a,b).

Fig. 4-2-11 Implant AQB T-type to

Fig. 4-2-12 Implant AQB T-type to thethe right mandibular molar region

first and second molars

Fig. 4-2-13 Antagonist teeth

Fig. 4-2-14 Occlusal relationshipFig. 4-2-15 Impression taking withFig. 4-2-16 Working model for thethe net impression tray

formation of individualized tray andcustom tray

Fig. 4-2-17 Recording the outine ofFig. 4-2-18 The individualized tray was

the individualized trafabricated with Unifast III (GC)Fig. 4-2-19 The custom tray wasFig. 4-2-20 place the tray alternately

fabricated with resin Quicky for

into warm and cold water to relieve

impression tray (Nissin Dental

internal pressure

Products Inc.)

Fig. 4-2-21 a,b Examixfine injection type was employed as the silicon rubber agent⑤ Fabrication of working model
1. Apply epoxy resin to the abutment site (Fig. 4-2-22)
2. Apply super hard plaster to the remaining space, and form a segmented type working model (Fig.
4-2-23).
3. Take impression of the abutment surroundings with silicon paste, and trim the abutment margin(Fig. 4-2-24).
4. State after the completion of trimming (Fig. 4-2-25).
5. A completed artificial gingival model (Fig. 4-2-26)

Fig. 4-2-22 Polyrock epoxy modelFig. 4-2-23 A working model wasmaterial (Metalor Dental, Inc.) wasfabricated with New Fujirock model

used as a measure for preventing

material

fracture of the abutment

Fig. 4-2-24 The margin was trimmed

Fig. 4-2-25 State after the trimming

using diamond point

Fig. 4-2-26 Soft tissue moulaghe (Sybron DentalSpecialties) was used as the artificial gingiva
materialIII. Method of impression taking to the fabrication of die for two-piece typeThe impression taking technique for AQB two-piece type implant is conducted in the same way as othertwo-piece types. The techniques comply with both the simple closed tray method as well as the precision
open tray methods (Fig. 4-2-27).
[Impression technique with rubber based material]① Take impression once the intactness of the gingivae has been confirmed after the secondary operation.
Connect the multi-abutment that corresponds with the implanted fixture, with HEX driver (Fig.
4-2-28).
② Take impression for the individual tray (Fig. 4-2-29).
③ Construct the working model from the impression tray (Fig. 4-2-30).

Fig. 4-2-27 Once confirming theFig. 4-2-28 Place the multi-abutment

healing of the gingivae, after thethat corresponds with the size of thesecondary surgery, take impression

buried fixture

Fig. 4-2-29 Close the access hole ofFig. 4-2-30 Be aware of the abutment

the abutment, temporarily, withfracture, particularly with certain

utility wax or cotton wool for taking

parallel orientation of implant

the impression with alginate
impression tray
④ To even out the thickness of the silicon impression agent, apply relief with use of paraffin wax. The
surroundings of the multi-abutment requires a relief space of over 5 mm to secure the space requiredfor pick-up coping.
⑤ Preparation of impression taking process for closed tray method (Fig. 4-2-31)
1. Produce a custom tray (Fig. 4-2-32).
2. Apply pick-up coping to the multi-abutment groove with elasticity (Fig. 4-2-33).
3. Place the pick-up coping so that the opening of the impression support faces the buccolabial sides(Fig. 4-2-34).
⑥ Open tray impression taking technique
1. Close the constructed hole with coping-screw using paraffin wax. If the hole is too large, the fillingpressure of the impression agent becomes reduced, subsequently affecting the accuracy of theimpression (Fig. 4-2-35,36).
2. Form a hole on the top of the pick-up coping, being cautious to avoid any of the tools touching thecoping screw (Fig. 4-2-37).
3. After the placement onto the multi-abutment, confirm that it is applied without any excess space(Fig.4-2-38).
4. Trial placement of the custom tray. In the open tray method, the coping screw should be insertedwith after softening the wax.
5. Insert silicon impression agent to the gingivae surrounding the multi-abutment and to the holding
portion of the pick-up coping, with syringe designed specifically for this purpose (Fig. 4-2-40 a,b).

Fig. 4-2-31 Apply relief on the cast so

Fig. 4-2-32 Fabricated with tray-type resinthat the top of the coping screw is

Quickyexposed roughly by 1 mm from the tray.

Fig. 4-2-33 The insertion of pick-up

Fig. 4-2-34 The pick-up coping may

coping should be checked with thebecome discolored or damaged if

clicking touchincorrectly applied

Fig. 4-2-35 Fabrication of open-tray

Fig. 4-2-36 The hole for the coping screw
should not be made unnecessarily enlarged

Fig. 4-2-37 Open a hole on the top of theFig. 4-2-38 Placement on thepick-up coping with a design knife

multi-abutment

Fig. 4-2-39 The positional relationship of the intraoral screw and the tray is easier to recognizewith the screw cavity

Fig. 4-2-40 a,b Exafineimplant (GC Co.) is available on the market as a silicon rubber impression
agent specifically for use of implants

6. Remove the impression material so that the coping screw is exposed out of the paraffin wax (Fig.
4-2-41).
7. Once the impression material has been set, loosen the coping screw with HEX driver bit to remove
the tray. The screw does not have to be removed completely as the displacement of the connection
to the fixture allows it to be moved up and down by 2 mm (Fig. 4-2-42).
8. Complete the impression taking procedure once the impression interior has been closely inspected.
With the open-tray method, the separation is possible between the fixture and the abutment, andmulti-abutment and pick-up coping. If the multiple fixtures could not be implanted in parallel,
there have been cases in which the multi-abutment is left remaining on the intraoral fixture. Afterthe impression taking, the multi-abutment in the oral cavity should be replaced with healing
abutment. The technical operation of this step also applies to the close-tray method (Fig. 4-2-43).
9. Fix the multi-abutment, the buried fixture and the implant analogue, with a corresponding
diameter, securely with an abutment screw. Pull the structure from both sides to confirm that nospaces are available for rotation or jerking (Fig. 4-2-44).
10. Restore multi-abutment and implant analogue to the pick-up coping. Confirm that it has beencorrectly restored and that it does not rotate or become dislodged easily (Fig. 4-2-45).
11. Reproduce the gingivae with silicon specific for artificial gingivae. Here, gingival mask soft(GmbH & Co. KG) was used as the silicone impression agent. The ideal thickness of the artificial
gingival silicone should allow for the joint of the multi-abutment and the implant analogue to bejust hidden.
⑦ Fabricating the working model
1. Apply the model material upon confirming setting of silicone artificial gingivae material. NewFujirock IMP (GC Co.), a modeling material specific for implant use was employed. The characteristicof this agent is that it limits the initial expansion as well as the residual expansion to the utmost. Themodel material can be removed roughly 40 minutes after its application (Fig. 4-2-47).
2. Complete the working model. When displacing the model, be cautious of it breaking (Fig. 4-2-48 to50).

Fig. 4-2-41 Remove the impression

Fig. 4-2-42 Loosen the coping screw

agents using various tools

using HEX driver bit

Fig. 4-2-43 completed impression

Fig. 4-2-44 Secure the implantanalogue firmly with abutment screw

Fig. 4-2-45 When connecting theFig. 4-2-46 Reproduce gingivae withcoping screw, ensure that no rotational

the artificial gingivae silicone

forces are not applied on the pick-up

impression agent.

coping or the multi-abutment

Fig. 4-2-47 New Fujirock IMP (GC Co.)

Fig. 4-2-48 The completed working
model from the labial side

Fig. 4-2-49 The completed working

Fig. 4-2-50 The state removed with themodel from the palatal aspect

artificial gingivae