dental implant prosthetics and abutments

Prosthetics

The prosthetic procedure shall be presented on simple examples of different types of
prosthetic constructions.

Choosing the Right Abutment Height

The proper height of the transgingival part of the abutments is very important for the final
result. It determines not only the proper function of the whole prosthetic construction but
aesthetic outcome as well.
When choosing proper abutment height it is helpful
to determine the gingiva height (GH = distance
between gingival margin and the implant.). This
should be done after healing period (full gingiva
maturation) using grooves on the healing abutment
(2mm, 4mm and 6mm the abutment top).

For overdentures it is important to choose the
lowest abutment possible (the higher the abutment
the higher the lateral-leverage forces on the
implant). Therefore, in some cases it would be
indicated to do gingiva correction rather than
choose higher abutments!

When choosing the right abutment hygiene should be taken into
consideration. It is extremely important to enable the patient
proper cleaning of the prosthetic construction. Therefore, in some
situations too short abutment may be an obstacle for good hygiene
(especially for bar overdentures).
Bite relation can also influence the abutment choice. In cases
when there is not sufficient space between the maxilla and the
mandible using certain types of abutments or even type of
restoration may be impossible or strongly contraindicated!
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For fixed constructions it is the general rule to choose the abutment so that the future margin of
the crown be hidden under the gingiva. This because of higher aesthetic demands for crown and
bridge works. For Octalock system, however, which has a range of abutments that can be easily
prepped to fit particular clinical situation, the dentist can choose a higher abutment and let his lab
correct margins in height to follow exactly the contour of the gingiva.
Every situation should be judged individually and the prospective decision should be a balanced
choice between local bite relations, implant mechanics, patient’s motivation and possibility to
keep the prosthesis clean.

Transgingival height - OCTA

Dyna Octalock System has been design to be flexible and universal. All
abutment lines are compatible with both implant diameters, which in practical term
means, that any of the Octalock abutments will fit either Ø3.6 or Ø4.0
interchangeably. Such solution does not require colour coding system for different
diameters. It saves also the need to have excessive
stock of prosthetic parts.
However, when choosing the proper abutment one
should remember that the effective transmucosal
height for the same abutment placed on different
implants will be different. To understand this
clearly please see the picture below.
Given the same total height of abutments placed on
different implant diameters there will be a
discrepancy in height between the top of the
implant and the margin of chamfer preparation (or
the top of the abutment). This discrepancy is
caused by the fact that the same abutment “fits
somewhat deeper” in the Ø4.0mm implant.
When using the product catalogue please notice information
between ( ) giving the exact transgingival height for Ø3.6 and
Ø4.0mm.

Screwing the Abutment
All final abutments must always be torqued onto the implants with 32
Ncm using the torque wrench instrument and adequate screwdriver. Every
abutment should be checked for fit (X-ray photo). This will prevent undesired
loosening and possibility of the abutment fracture.
The abutment must be screwed in full contact with the implant without any debris
between.
All final abutments, must be checked for loosening after a few weeks, meaning
that the final restoration may only be produced/finally cemented after re-screwing
(Torque Wrench) of the abutment.

Torque Wrench Use

The Dyna Torque Wrench is a special instrument used to screw Dyna
abutments to the torque of 30 or 35Ncm*. It should be used with all Dyna
abutments to screw them into implants definitively and prevent from
unscrewing. (see also instruction for use delivered with the Dyna Torque
Wrench).
*Apply 35 Ncm indication for all abutments placed directly on implant level
Apply 30 Ncm indication for all abutments placed on extension level
The Dyna “S” drivers can also be used in combination with the ITI
Straumann Torque Wrench.*(see also 5.3)
Dyna Torque Wrench should be calibrated once a year for proper torque.
*ITI Straumann is a registered name of the ITI Straumann(CH)

Anti-rotation IMPLANT-ABUTMENT
It has been proven that loosening of the
abutments, especially with single tooth
replacements, can be prevented by screwing the
abutment into the implant with sufficient torque.
This torque will result in an upward force (preload)
onto the implant threads so friction will
prevent the abutment from rotating.


Research showed the torque of 32Ncm to be ideal to prevent the Dyna abutments
form loosening without overloading them. The desired amount of torque depends on the
materials used and the quality of the threads, No compromises are in the production of
Dyna products. All implants and abutments are made of Ti grade 5 and are equipped
with the most accurate threads (6H/6h).

It is recommended to reapply the same torque to the abutment, after one or two
weeks, before cementing the prosthesis. As there is some relaxation in every material,
causing a reduction of the pre-load. Retightening can prevent the abutments from
unscrewing.
Therefore, in cases of fixed constructions producing a temporary crown or bridge
has two major advantages:
-possibility to screw the abutment again
-possibility to form the gingiva in desired way and achieve maximally aesthetic
result.

Octalock System has been designed to achieve 0 degree rotation in the clinical use,
as well as to enable easy transfer of the situation in the patients mouth to the lab model. The use
of the octagon and conical connection has been carefully chosen.

Any antirotation is of no use when there exists a significant freedom of movement between an
abutment and an implant. Most of the systems present on the market, nowadays, have a rotational
freedom of 4 to 12 degrees. This may influence clinical performance of any prosthetic
construction and make the accurate transfer mouth-model virtually impossible. Only a 0 degree
rotational freedom can guarantee the best results, as only then the implant analogue position in the
model will be the same as in the mouth.
Dyna Octalock system has been designed to the make transfer procedure as precise as possible.
To assure this, the octagon connection has been planned so that the external octagon has slightly
tapered walls (around 1 degree). Due to this modification by means of micro deformation,
abutments are prevented from any rotation once seated and screwed in the implant. This 0 degree
rotational freedom results in a perfect , trouble-free transfer from mouth to the model and vice
versa. This means in terms of practical usage, no more problems with taking impressions. The
fixed prosthesis is made in the lab on the same abutment as the one placed later in the mouth of the
patient, and therefore, it will always have a prefect fit.
Because of the fact that the tapered octagon suffers only minor deformations, the conical
connection placed above it provides a perfect seal from the outside environment. Choosing two
different angulations always results in a 100% closed connection between the implant and the
abutment. At the same time this conical connection provides a stable fit in the implant, which
makes the whole construction very solid an generates the ideal distribution of the applied forces.
To protect the fixation screw from braking and unscrewing it has been added a conical head. This
provides the same stability as the conical connection and makes the whole system self centring.
Due to friction forces only a small amount of the applied torque will be transferred to the thread of
the screw resulting in a considerable tension relaxation. This, in combination with the conical
connection, makes it almost impossible to overload, and brake the screw during normal
physiological use.
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The internal octagon has been introduced for several reasons:
 Increase of the implant wall strength (comparing with the hexagon design) – allowing for
the same diameter of the fixating screw and the hexagon\octagon wall, the minimal
thickness of the implant wall for hexagon design is about 30% thinner than for analogue
situation with octagon design.

 improved aesthetics – the octa has been chosen to be internal instead of external so that no
space is lost from the connection upwards. In this way it is possible to use a very low
abutment in all those situations where the gingiva thickness is insufficient, so that no
compromise in aesthetics has to be made.
 possibility of adding the morse taper above it – in this way the new connection joins the
best features of the other renowned implants systems in one, giving the security of equal
force distribution, brake protection and the best aesthetics.
 increase of the prosthetic positions for e.g. the angulated abutment

Antirotation ABUTMENT-CROWN
Dyna Octalock System has been provided in a reliable system
preventing loosening of the abutments during clinical function.
Combination of internal octagon and conical surfaces gives the
guarantee for precise fit and stabilisation. Nevertheless, when
restoring single elements its is important not to forget about
antirotation for the crown (crown-abutment antirotation). Dyna
OCTALOCK abutments have no special antirotational structures
solving that problem (contrary to all-in-one Dyna abutments that
have standard either special grooves or castellated parts).
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It is the user’s responsibility to provide the finally prepared
abutments in antirotational structures.
In case of using standard abutments it is possible to create a “side
groove” on it or prepare the upper part so that it would have sort of
U formed cuts. In case of using Universal abutments it is the
technician who makes antirotational structures.

Impression Technique

There are several impression techniques that can be used for the Dyna
abutments:
8.5.1 Transfer technique/pick up technique (ball abutment)
Special standardized transfer copings for transferring the position of the abutment exactly
and reliably onto the master model are needed in this technique.
Once the gingiva has healed the healing abutment is unscrewed and replaced by the proper
ball abutment. The transfer coping is than clicked onto the abutment and the usual
impression with individual tray can be taken. As the impression material has set the
impression is pulled out and the position of the coping in it is checked. Ball laboratory
analogues are then clicked into the copings and the master model is casted.
8.5.2 Open-tray technique (bar abutment, alternatively medical or fixed abutment)
An alternative method (transferring the position of the implant) is to use an open tray
technique. In this case the individual tray is provided with opening(s) over the implants The
impression copings are screwed in with the long fixation screws, replacing the healing
abutments. The tray is checked in the mouth. There should be enough space for impression
material, and the screws should stick out of the opening(s). The opening(s) should be
covered with soft wax and the impression may be taken. Once the material has set the long
fixation screws are unscrewed and the impression is pulled out. Using the same screws the
lab implant analogue is connected by the dentist or technician to the impression copings, and
the master model poured out. It is important not to change the position of the copings in the
impression material during manipulation.
When taking the impression over more implants we recommend splinting the impression
copings with one another before actual impression taking.
For Octalock system, designed so that both the technician and the dentist could work on the
same abutment, the open tray technique is the method of choice.
8.5.3 Standard impression (fixed abutment)
Some situations demand taking a standard impression as for eg. crowns and bridges on
natural dentition. In such cases first the healings have to be replaced by chosen abutments
and the impression can be taken as usual. After pulling out, the model can be cast directly
after repositioning of the laboratory abutment analogues.*
*more details about this technique will be given on Dyna courses

Sterilization
All prosthetic components are supplied clean but not sterile. Operator is
obliged to sterilize them or disinfect in appropriate manner

Shape of the Fixed and Memory Abutments GG GN

Transgingival part.
The transgingival shape is made according to the aesthetic principle* The GG abutments, with a
diameter of 6mm for the Ø 3,6mm and Ø 4mm implants and 7mm for the Ø 5mm implants, are
indicated for central incisors and first and second molars. The GN abutments for the Ø3.6mm and
the Ø4.0mm implants have a diameter of 5mm and a diameter of 5,5mm for the Ø5mm implants.
The GN abutments are available in a trans-gingival height of 2, and 3mm and are meant for all
crown & bridge indications. Ø 3.6, 4.0, 5.0 GG and GN memory abutments can be screwed into
the implants by means of the special GG instrument and torque wrench. Ø3.0 memory abutments
have the outer diameter Ø5.0 and are produced without the castellated part. They should be
screwed with the universal memory instrument.
*The abutments are designed with a convex shape offering the following advantages:
1. the different diameters allow the technician to produce fixed prosthetics with better
aesthetics
2. the convex shape provides more freedom for the papillae
3. there is no downward pressure on the surrounding gingiva, so the margins of the crown
or bridge stay more subgingivaly.
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Supragingival part (abutment-head)
The height of the abutment head is always 6mm. Because of the castellated design of the GG
abutments and the GN Memory abutments the Torque Wrench can be used to obtain the optimal
torque. The GN fixed abutments are screwed into the implant by means of the Memory instrument
without Torque Wrench and therefore are not meant to be used for single tooth restorations*.
*This limitation can be solved with Dyna Octalock implants and abutments. Please refer to Dyna Octalock Manual.
Note:
Always bend the Torque Wrench twice manually before use! Read the instructions of use!
The new GG instrument (art. code 5383) that can be used in combination with the Torque Wrench
(art. code 5083) exactly matches the castellated shape of the abutments.
Note:
The previous (concave) healing abutments for crown & bridge for Ø4.0mm implants (5815) can
not be used with the new (convex) GG and GN abutments!

Memory Abutment

In many clinical situations it is not possible to obtain an ideal path of insertion
(especially in the maxilla) for fixtures, corresponding with the loading axis of the prosthetic
construction. Bone quality and quantity limitations, position of anatomical structures are one of
the reasons influencing potential choice of implantation place. The main reason, however, seems
to be the protrusive shape of the anterior maxillary part which develops due to the horizontal
resorption of the alveolar bone.
In such cases the clinician faces two options: applying advanced bone remodelling techniques or
using angulated abutments. The latter solution though biomechanically unfavourable seems to be
much easier and more useful in everyday practice.
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One of the solutions is to offer besides standard straight abutments also pre- angulated ones.
They can be angulated between 5o and 20o . Consequently, there is a necessity to have whole
range of these abutments, available at the moment of abutment installation, to meet all possible
modalities. Moreover, they often have to be additionally adjusted to achieve desired parallelism.
Dyna memory abutment is an adjustable abutment system based on the use of shape memory
alloy allowing to avoid aforementioned problems. The system consists generally of one type of
abutment that can be angulated between 0o to 20o .
This eliminates the need to have very expensive stock in hand and allows for obtaining
uncompromised parallelism.
The world wide patented Dyna memory abutment is an assembled two part implant abutment to
be used in all types of fixed prosthetic appliances together with Dyna Implant System. The
transmucosal matrix part is produced out of titanium and the patrix out of nitinol.. Both parts
create a sort of a ball joint and thanks to sufficient friction are rigidly connected in body
temperature. When the temperature of the patrix decreases to around 0o the abutment head can
be moved with Memory Instrument to the desired angle.
The idea of this abutment is based on a friction force, strong enough to create sufficient retention
between two elements, that can be changed (using the memory shape effect). Memory effect is
used in such a way that the two parts of the patrix ball that in room temperature are under
considerable pressure (high friction) inside the matrix would move to each other when cooled to 0
degree, thus releasing internal pressure (low friction) and allowing the abutment head to rotate
inside the cup. With an increase of temperature the two halves of the ball regain their pressure by
going back to their primal position (shape memory) and fix rigidly matrix and patrix.
A similar idea though achieved by applying sufficient mechanical force is used to fixate the
abutment itself in the implant. Screwing it with around 32 Ncm torque creates friction force
between screws of the abutment and implant that can be in physiological conditions considered as
antirotation protection.

Hygiene Requirements
Every construction made on implants should include in its design hygiene aspects.
This means that patient should be able to keep the prosthesis clean. It is the dentist task to access
patient’s ability and motivation to perform everyday hygiene and afterwards decide on type of the
prosthesis. On the other hand it is the technician task to produce a construction easy to clean
arranging e.g. interproximal spaces to be easily accessible with interproximal brushes.
Proper hygiene is conditio sine qua non for predictable functioning of the implant supported
prostheses.