The document discusses various impression techniques used for dental implants. It describes the key components used, such as implant analogues and impression copings. The most common impression materials are vinyl polysiloxanes and polyether rubbers due to their dimensional stability and detail reproduction. Direct open tray techniques involve exposing the impression coping screws and incorporating the copings into the impression tray. Indirect closed tray techniques retain the copings in the mouth and reattach them to analogues in the lab. Factors like implant angulation, number of implants, and interarch space determine whether open or closed tray methods are preferred. Accurate transfer of the implant positions is crucial for passive fitting of the final prosthesis.

1. Impression Techniques in
Implants
Mohammad Ibrahim AL-graisi
BDS-Msc
PROSTHODONTIC DEPARTMENT

2. Introduction:
• The main goal of an impression implant restoration is to accurately relate
an analogue/abutment of the implant to the other structures in the dental
arch. This review focuses on the components, impression materials and
the various impression techniques that can be used in implant restorations
with note on recent advances in implant impressions
• The success of implants depends on its osseointegration and the passive
fit of the prosthesis.
• The discrepancies in the passive fit of the prosthesis may lead to
complications such as screw loosening, screw facture, occlusal
discrepancies, increased plaque accumulation, resulting in loss of
osseointegration and implant fracture.

5. Impression Materials:

6. A primary concern when dealing with the impression restorations is accurate
transfer of the relationship of the implant and /or any remaining dentition to the
master cast
If the transfer of the analog is not accurate it will affect the passive fit of the
prosthesis, for this the impression material used should be resilient enough to
spring out of the undercuts and stiff enough to allow for accurate seating of the
components in to impression
It should also prevent dislodging of the components during the pouring of the
impression and avoid the fracture of the stone when the prepared abutments are
small. Thus the impression material should be sufficiently flexible and rigid.
The most commonly used impression materials in implant dentistry are vinyl
polysiloxanes and polyether rubber base impression materials.
Vinyl polysiloxane impression materials are often used as they have excellent
dimensional stability, superior deformation recovery and accurate reproduction of
details. The mechanical properties of the siloxane impression material are adequate
to withstand various stresses upon removal and maintain dimensional stability.

7. The most important property of an impression material is its wettability which helps provide
detail reproduction in wet oral surfaces and also reproduces the details accurately with
gypsum slurry.
A newer impression material Vinyl polyether silicon (VPES) which is a combination of
vinylpolysiloxane(VPS) and polyether(PE) has been introduced which according to the
manufacturer has intrinsic hydrophilicity and high dimensional stability.

8. Components

9. Implant Analogue or Replica
are metal replicas that duplicate the implant head or abutment connected to the implant
which are used in laboratory to construct working model.

10. Impression copings
have been designed for making final impression after the soft tissue has matured. These
copings have the same flare as the healing abutments and should fully support the soft
tissue around the head of the implant. They are various types of copings available which
are selected based on the impression techniques.
In transfer type the coping is retained in the mouth when set impression is removed.
In pick up type the coping gets incorporated in the impression and it is removed from the
mouth with the set impression

11. Impression Techniques:

12. IMPLANT LEVEL IMPRESSION TECH
Direct Impression techniques (Open tray, Pick Up): A custom or stock open tray
with access to the impression coping screws is required, which exposes the coronal ends
of the impression coping.(fig:2) Impression material is syringed around the impression
coping and filled tray is then inserted into the mouth, ensuring that guidepin of the
impression coping is visible and protrudes through the hole in the tray. Impression
copings are unscrewed and they are removed from the mouth together with the set
impression.(fig:3)The implant analogues are connected to the copings using the same
screw.(fig:4). Some precautions to be taken are: radiographically confirmed seating of
impression coping to the implant and use vinyl gloves when elastomeric impression
material is used.This technique can be used for single tooth restorations, multi-unit
restorations and implant over dentures for either cement retained or screw retained
prosthesis.
FIGURE 2 FIGURE 3 FIGURE 4

13. An advantage of OPEN TRAY technique
• is the dentist can confirm the laboratory preparation and contour of the provisional
prosthesis to achieve the desired healing and soft tissue contour before final crown
fabrication.26
• The direct technique can be further subdivided into splinted and non-splinted
techniques. The splinting procedure is recommended in case of multiple implants to
decrease the amount of distortion and to improve impression accuracy and implant
stability. Splinting of the transfer copings prevents rotational movement of impression
copings in the impression material during analog fastening, which provides better
results than not splinting.
• Reduces the effect of the implant angulation
• Reduces the deformation of the impression material.
• removes the concern for replacing the coping back into its respective space in the
impression.
Disadvantage of Open Tray
• The movement of impression copings inside the impression material during clinical
and laboratory phases may cause inaccuracy in transferring the spatial position of
implants from the oral cavity to the master cast.
• some rotational movement of the impression coping when securing the implant analog
may occur.
• Blind attachment of the implant analog to the impression coping may result in a misfit

14. Indirect technique(closed tray):
An indirect technique is also known as closed tray impression technique.The copings are
connected to the implant (fig:5)and after the removal of impressions they are retained on
the implants. These copings are then removed from the implant, attached to the implant
analogues and reinserted in the impression. (fig 6&7).Clinical situations which indicate the
use of the closed tray technique, such as when the patient has limited interarch space, a
tendency to gag, or if it is too difficult to access an implant in the posterior region of the
mouth.
FIGURE5 FIGURE 6 FIGURE 7

15. Advantages of Closed Tray
Easier
Suitable for short inter arch distance.
Visual fastening of the analog to the coping is more accurate
Disadvantages of Closed Tray
Inaccuracies with recovery and subsequent deformation of impression material may be
encountered with nonparallel implants.
Not Suitable for deeply placed implants.

16. ABUTMENT LEVEL IMPRESSION TECHNIQUES
Direct techniques
By intra oral preparation of the abutment
Indirect techniques
• Open tray techniques
• Closed tray techniques
• Press-fit techniques