Precision
attachments such as Dalbo / Swiss Mini, Ceka / Swiss Anchor or Split Roach
Ball and many other precision attachments have their limitations. A recent
study by M. Wichmann, DDS and W. Kunz, DDS “Wear Study of Attachments
“Journal of Prosthodontics, 12 404-9, 1999 has determined that conventional
metal attachments showed significant wear and retention loss. By contrast
the plastic attachments showed only negligible friction loss and the most
consistent retention force. In addition, replacement of the plastic inserts
restored friction to the initial manufactured retention. Furthermore the
study concluded wear induced loss of retention in attachment retained dentures
poses a major clinical problem. To counteract this unwanted effect, most
prefabricated precision attachments can be activated to restore wear induced
loss of friction. This is achieved by design elements such as resilient
metal tongues, partially or completely slotted male components or set screws.
Over time activation of these metal male components will induce fatigue
of the metal alloy followed by breakage of the retention elements, if they
have not already worn out during daily function. The question is then how
costly will it be to replace the existing abutment restoration with the
same attachment system? Or should you consider another approach? A recent
innovation by Bredent has revolutionized attachment systems. The existing
VKS- OC/SG stud attachment has been engineered with a threaded
screw and a reversed hex at the head of the stud, which can be rotated
in or out of the restoration when necessary. This exchangeable stud will
be able to be used vertically with the OC retention sequence or horizontally
with the SG retention sequence. The exchangeable stud will extend the life
of the restoration far beyond accepted parameters. The exchangeable stud
can be replaced intraorally when the plastic retention sequence of green,
yellow and red are exhausted. Indications for use are bilateral removable
partial dentures, implant bar supported over dentures and root cap treatment
over dentures. The exchangeable stud is made of titanium, whereas the retaining
housing is offered in platinum / iridium or a gold, platinum/ palladium
alloy. Procedures both clinical and technical are relatively simple. In
the laboratory the exchangeable male stud and retaining housing are waxed
to the abutments or bar following the path of insertion. Using the hexagonal
screw driver the titanium stud head is rotated out of the threaded housing
counter clock wise. Prior to investing the waxed abutments or bar, the
retention stud must be replaced with the fixation pin. Colloidal Graphite
is applied on to the threads of the fixation pin before investing so as
to protect the integrity of the threaded housing as it is being held in
place during the burnout and casting procedure. Later the casting is sand
blasted and the fixation pin is turned out before porcelain application
on the crowns. In the case of the bar or root caps treatment the stud is
replaced into the housing and it is polished to a high luster with titanium
polishing paste. The yellow retention sleeve is positioned on the stud
and the model is prepared for duplication of the removable full or partial
denture. Clinically, when the retention sequence is exhausted and the stud
wears, it can be removed intraorally and replaced into the existing abutments
or bar. Then a new retention sequence can commence. This procedure can
be performed indefinitely, provided that proper maintenance of the restoration
is carried out. Source; Peter T. Pontsa RDT. For further information
contact us at 1-800-250-5111 or E-Mail: info@dent-line.com
Multisil-Soft
is a silicone denture relining material suitable for new and old restorations
that are based on polymethyl-methacrylate material. The indicated range
of usage is for cushioning of hard palate,as an over denture during the
healing phase following implant placement , subsequent to multiple tooth
extractions and to relieve pressure areas in the upper and lower jaw. Multisil-Soft
is specifically for indirect preparation of full or partial dentures. It
is packaged in dual cartridge auto mix format with dosing gun.
Most types of acrylic based relining systems require messy handling procedures
were as the Multisil-Soft has flow characteristics that allow rapid processing.
When cured the material is permanently elastic and prolonged comfort of
wear is a distinctive feature. To process this material the model and denture
are placed into a reline unit. The areas of the denture to be relined is
reduced by 2 mm then a chamfer 1 mm deep is prepared in the vestibular
area 3 to 4 mm above the peripheral borders. The surface can be cleaned
with oil free air. The master model is sealed with separator (e.g. Isoplast
54001019). Apply Multisil Primer onto all areas to receive the material
and let dry three minutes. Then apply the Multisil-Soft uniformly and completely
onto the prepared areas. At room temperature the material can be processed
in approximately three minutes. Once the application is complete, the reline
unit is closed and curing is either carried out under atmospheric pressure
or in the pressure pot at 45â Celsius. Deflasking is carried out
after hardening time of 15 minutes. Polymerizing in the pressure pot should
be the preferred method since it increases physical values for the resin-silicone
bonding system. When Multisil-Soft is totally cured it exhibits exceptional
wear and tear. The functional margins and transitional zones are contoured
using a scalpel or silicone bur (S237QG65). Alternatively there are two
other silicone burs that can be used to finish other areas (S263QG60) and
(S187QG23). Next apply Multisil Soft sealing agent onto the processed silicone
areas and allow it to air dry. The sealing agent adds a permanent shine
to the silicone surface and protects against accumulation of plaque and
penetration of bacteria into the surface. Multisil-Soft has a shelf life
of two years if it is stored in the original sealed container at room temperature
under 28 C and protected against sunlight. The relined denture can be cleaned
by the patient several times a day under running water with a tooth brush
and a non abrasive soap. If an ultrasonic is used the denture must be placed
in a zip lock bag with some water in it before being submerged in the cleaning
system. Failure to do so will result in the reline material separating
from the denture. Source; Peter T. Pontsa RDT, for additional
information contact Dent-line of Canada Inc. at 1-800-250-5111 or E-Mail:
info@dent-line.com
Dent-Line of Canada Inc. Would like to congratulate the participants
who completed the Bredent Vario Soft 3 attachment and milling course held
this past November 9th and 10th at Lab Dentaire de l’Outaouais. Peter T.
Pontsa, RDT (centre) facilitated the course while giving encouragement
and guidance during the attachment placement and with the milling techniques.
The Dent-liner; Vol. 7, No. 1
Publisher: Peter T. Pontsa RDT
Editor: A. Van Breemen BA
E-Mail: info@dent-line.com
Subscription Rates:
Canada
1year $5.00
USA
1 year $7.00
International 1 year $15.00
