Over dentures/ orthodontic straight wire technique

OVER DENTURES
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com
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INTRODUCTIOININTRODUCTIOIN

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• It is recognized that, this technique
helps reduce impact of some of
complete denture wearing
consequences like :-
• Residual ridge resorption;
• Loss of occlusal stability;
• Undermined esthetic appearance
• Compromised masticatory appearance

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REGARDED AS A FORM OF PREVENTIVE
THERAPY.
PREVENTIVE
PROTHODONTICS

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DEFINITION:
A removable partial denture or complete denture that covers
and rests on one or more remaining natural teeth,the roots of
the natural teeth,and/or dental implants.
A prosthesis that covers and is partially supported by natural
teeth ,natural tooth roots and/or dental implants.

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THIS IS ALSO CALLED AS
• OVERLAY DENTURE.
• OVERLAY PROSTHESIS

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• IMPORTANCE OF THE OVER DENTURE.
.
• NEUROMUSCULAR CONTROL &TACTILE
DISCRIMINATION.
• ROOT PREPARATION.
• DIFFERENT TYPES OF ATTACHMENTS.

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ROOT PREPARATION :
• PLANING OVER DENTURES.
• SELECTION OF THE ABUTMENTS.
• SPACE REQIREMENTS.
• BARE ROOT FACE.
• PRECIOUS METAL COPINGS
• METHODS OF RETENTION.

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IMPORTANCE OF THE OVER
DENTURES:
• PSYCHOLOGICAL BENEFITS TO THE
PATIENTS.
• THE EFFECT UPON THE EDENTULOUS
RIDGE.
• TACTILE DISCRIPTION.
• IMPROVED STABILITY AND RETENTION OF
THE PATIENT.

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PSYCHOLOGICAL BENEFIT
TO THE PATIENT.

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EFFECT UPON EDENTULOUS
RIDGES
REVIEW LITERATURE:
In 1967&1969 TALLGREN showed that
reduction of anterior height of mandibular
ridge was 6 times greater than maxillary
residual ridge.
2.Mean loss of mandibular ridge was
6.6mm &maxillary ridge is 1.6mm.

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• Where as bone loss in partially
edentulous ridges in lower jaw
is 0.8 and he showed that wide
& unpredictable range of
resorption pattern found in
patients 3-6months after
complete denture insertion

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• CRUM & ROONEY (1978) :retaining of
mandibular canines for over dentures
helped to preserve the remaining
edentulous ridge.
• An interesting finding was that
patients with remaining canines lost
less ridge height in region between
the canines than those without any
natural teeth.

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• CRUM(1978):
• In a 5 years study patients
wearing over denture lose about
8 times less bone than those
with complete denture in the
anterior region.

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• LORD &TEEL (1974)
They stressed that “teeth that are too
weak for normal partial dentures
abutments may be suitable for over
denture.”
This type of approach was
particularly recommended when
denture was opposed by natural
teeth.

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• WICAL & BRUSSEE(1979):
• He claimed that alveolar ridge
resorption can be reduced for
patient with immediate
replacement denture by means of
supplemental calcium & vit.D

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NEURO MASCULAR CONTROL &
TACTILE DISCRIMINATION
• There differences between subjects with
complete denture and over dentures in
neuro physiology.
• Over dentures may impart a mechanical
stability which itself enables an improved
neuromuscular performance by the
subjects.
• Enhanced perception of occlusal forces
improves the subject ability to grade them
because of the proprioreception.www.indiandentalacademy.com

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• The stability offered by an over
denture might be expected to provide
a more resistant platform for the
generation of the force by
masticatory musculature.
• There is difference between
interocclusal force that is given by
over denture patients &complete
denture patients. Stable occlusal
foundation gives more inter occlusal
force than the unstable one

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• Preservation of the periodontal
input providesneuro
physiological bonus to the over
denture patients.
• This proproception is due to
mechanoreceptors that are
present in the gingiva alveolar
bone & periosteum

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PERIODONTAL TREATMENT FOR
THE OVER DENTURE PATIENTS:
• Plaque score has to be taken.
• This provides the base line for the
evaluation of the oral hygiene on ongoing
treatment plan &patient motivation.
• A color coded periodontal probe should
be used to plot the pockets depths on
mesial distal ,buccal& lingual sides.

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DIAGNOSIS
• Clinical &radiographic
examination has to be established
to examine the gingiva & alveolar
bone

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PROGNOSIS
• The roots that are remain beneath the
over denture should be spaced out
around the dental arch.
• Where the adjacent roots retained
prognosis is less satisfactory.
• Canine teeth provide the most
frequent abutment beneath the over
dentures
• Canines are usually amongst the last
teeth lost due to periodontal diseasewww.indiandentalacademy.com

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IDEAL REQUIREMENTS OF
THEABUTMENTS FOR OVER
DENTURES
• The gingival tissue should be firm,pink &tightly
attached to the neck of the tooth &underlying bone
• A sufficient level of alveolar &supporting bone
should remain free from angular bony defects.
• The abutments should be definitely root filled and
free from caries.
• The abutments should exhibit a minimal degree of
mobility once they have been sectioned 2-3mm
above gingival marginwww.indiandentalacademy.com

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SEQUENCE OF TREATMENT:
• Emergency care
• Disease control
• Extraction of badly decayed teeth
• Transitional partial dentures
• Endodontics
• Periodontal surgery
• Waiting period for the maturation of the tissues
• Construction of the over dentures.www.indiandentalacademy.com

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PRELIMINARY PERIODONTAL
TREATMENT
• SCALING
• ROOT PLANNING
• PLAQUE CONTROL

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CORRECTIVE PERIODONTAL THERAPY
• The depths remain following preliminary
periodontal treatment corrective procedure are
required.
• The periodontal tissues beneath over denture may
be at greater risk than those around normal teeth'
due to build up of the plaque &irritation that may
occur from movement of the denture base under
these conditions,pocket correction procedure may
break down the reformation of the pocket depth.

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POCKET ELIMINATION PROCEDURES
• An internal bevel incision carried out
around the abutment teeth using no.15
blade just apical to the gingival margin.
• “tramline”incisions are used along the
crest of the ridge.once the incision has
been completed the full thickness flap is
then detached from the underlying bone

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• In order to position the flap apically
the dissection must be carried a
sufficient distance to allow the flap to
drape it self without blanching ,when
it its positioned with its gingival
margin just coronal to the alveolar
crest
• Buccal side often possible to use the
split thickness flap

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PLANNING FOR OVER
DEUTURES:
1.PERIODONTAL CONSIDERATIONS OF THE
OVER DENTURE.
2. TOOTH LOCATION.
3. ENDODONTIC COSIDERATIONS
4. NO.OF OVERDENTURE ABUTMENT TEETH.
5. THE AMOUNT OF SPACE BETWEEN THE
ABUTMENTS
6.SPACE REQUREMENTS.
7.BARE ROOT FACE.www.indiandentalacademy.com

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Periodontal considerations
• Reducing the tooth to the gingival level
drastically reduces the leverage forces.
• As a rule of thumb, where 1/3rd
of the root
remain in the bone will not withstand the
significant loads.
• Where the bone support is greater some
lateral loads may be applied to provide
essential stability to the prosthesis.

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TOOTH LOCATION:
• The canine regions are strategic positions for
the over denture abutments.
• With regard to lower denture it is wise to select
the teeth that can be joined by an imaginary
line at right angles to the sagittal plane rather
than provide a diagonal fulcrum line.

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ENDODONTIC COSIDERATIONS:
• Sound teeth with satisfactory root fillings must
obviously be strong candidates for the
abutments.
• Single rooted canal easier to root fill than multi
rooted teeth.
• Multi rooted teeth with hemi section procedure
are normally valuable in these areas.

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NO.OF ABUTMENTS:
• Two abutments on opposing side of the arch
say, in canine regions will give excellent
results.
• If more abutments are retained, it will
complicate construction of the over denture.

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THE AMOUNT OF THE SPACE
BETWEEN THE ABUTMENTS:
• Adjacent roots can complicate the plaque
control &denture construction.
• If adjacent roots to be preserved,it is better to
restore the individually .
• Connecting the root surfaces has several
mechanical advantages like inclined loads
resolved in more axial direction and there will
be a marked resistance to loads with lateral and
rotational components.

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SPACE
REQUIREMENTS
Over dentures tend to occupy more vertical
space than the tooth substance that they
replace.The reason is more bulk material is
required for the strength of the denture base
material
When additional components are added the
space available is further reduced.
Buccolingual space &labiolingual space
requirements also needs considerations.

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BARE ROOT FACES:
• Occlusal section of the root canal can be obturated
with glass ionomer &silver amalgam.
• If the roots are curved highly polished surface can be
produced to have following advantages: -
• It is the simplest cheapest &least space consuming
solution.
• It is ideal solution during maturation of the edentulous
ridges.
• This approach can also be used to evaluate the
questionable abutments.

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COTRAINDICATIONS:
• It should not be used on along term basis
.where natural teeth are indirect opposition.The
incidence of longitudinal root fracture has been
significantly raised
• It should not be used on long term basis unless
a highly polished surface can be produced

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OCCLUSAL SURFACES
• In many respects porcelain is the ideal artificial occlusal
surfaces both from point of view of appearance and
function.
• porcelain require mechanical retention within the
acrylic resin with denture base.
• This mechanical retention requires vertical space, a
precious commodity where remaining roots are covered
by a denture.
• The differing coefficient of expansion between
porcelain acrylic resin increases likelihood of stress
concentration around the artificial
• weakens the prosthesis.

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• The are certain advantages and disadvantages if
porcelain over acrylic resin teeth.
• -porcelain is brittle material that chips cannot be used n
cross section.
• Porcelain teeth are some what heavier than acrylic
resin counterparts so that despite the complete denture
use ,once over denture planned there are remarkably
few situations in which porcelain occlusal surfaces can
be employed.
• Acrylic resin teeth directly bonds to the denture base
&the required Buccolingual is less than porcelain teeth.

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• The wear resistance of acrylic teeth is less
compared to porcelain teeth.
• Wearing acrylic resin teeth with gold occlusal
surfaces is in many respects the ideal
arrangement it is particularly useful where
acrylic teeth opposed by natural teeth
surfaces.acrylic resin teeth have high rate of
wear.

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Methods of retention
• Borders seal always plays an important role in
retention
• Incase of over dentures simple copings are
involved in the primary form of retention.
• The location and number of retainers also plays
an important role .
• Excessive retainers complicate the construction
of the prosthesis, they make plaque control
more difficult and weakens the denture.
• Grip forces 300- 500gms/retainer gives
adequate retention.www.indiandentalacademy.com

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• After the root preparation there different
methods for obtaining retention &stability.
• 1.precious metal copings.
• Dome shaped copings.
• Attachments.

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PRECIOUS METAL COPINGS
• The wide variety of shapes &contours are
available for to give the operator enormous
scope with the design of the restoration.
• Gold copings can be used to impart the
stability &retention.
• Crown &sleeve coping retainer similar to gold
coping also gives the better retention
&stability, but because of the rounded form
denture will move when horizontal forces are
applied.

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• C.This problem can be overcome by using inner&outer
copings.
• The inner coping cemented on the tooth &the outer
copings forms the part of the denture base.
• There are certain advantages &disadvantages of using
acrylic outer copings.
• The degree of stabilization &retention can be
controlled by the operator.
• it is comparatively easier to do the adjustments.
• if the copings has to be placed on the adjacent teeth
it is difficult to place the metal copings because the
proximal surfaces may interfere.
`

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• Another approach of making copings are simple
thimble shaped copings.
• Thimble shaped copings needs considerable
vertical &Buccolingual space further more this
coping must be covered by adequate thickness of
the denture base material.
• The retention obtained for the over denture will vary
inversely with tape of the coping.
• The recommended height of the preparation is
4mm.
• This thimble shaped copings are particularly useful
in the awkward distribution of the teeth.

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DOME SHAPED COPINGS.
• The height of the preparation for using dome shaped
copings is 2mm above the ridge crest.
• Because of the mall size, lateral loads are reduced
&spaced occupied is minimum.
• Their contribution to the retention of the prosthesis is
negligible.
• This can be recommended where the thimble copings
cannot be be used.
• Easier for the impression procedures&location
procedures.
• This can be used for the immediate replacement of the
over denture. www.indiandentalacademy.com

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• The design of the preparation is simple
,chamfer finish line is given.
• The design of the coping must be taken
into account,the space available,and the
forces that will withstand ,and must be
contoured to facilitate the plaque control.
• The coping should be at least 1mm thick to
with stand the forces.

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ATTACHMENTS
The third option available for the retention &stability of
the over denture is using attachments.
• USES:prefabricated attachments provides
considerable retention&stability.
• These attachments are normally midway between
simple dome shaped copings &tall thimble shaped
copings.
• A wide range of the attachments are available that
range from traditional mechanical units to those which
retention &stability is obtained by magnetic forces.

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• Employing attachments adds to the expense
of the restoration.
• Attachments not only requires precise location
between the various components,but may
place additional forces on their dowels.
• Nevertheless in selected patients they give
satisfactory results.

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ATTACHMENT SYSTEMS
• Stud attachments are simplest among the all
attachments.
• The male part consists of stud shaped projection
soldered to the diaphragm of dowel retained.
• The female part fits over the male unit &
embedded within the denture base of the
prosthesis.
• They are relatively small they can provide
additional retention,stability &support.
• In inadequate vertical space,less bone support of
the root these dome shaped copings are
recommended. www.indiandentalacademy.com

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• They are of two types :
• 1.Extra radicular:-in which male elements
projects from the root surface of the
preparation.
• 2.Intra radicular:-in which the male element
form the part of the denture base & engages
a specially produced depression with in the
root contour. www.indiandentalacademy.com

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USE OF ATTACHMENTS
• Prefabricated attachments are versatile and
may provide considerable retention and
stability.In some instances the additional
retention may have dramatic effect on
restoration.
• A variety of attachments are available that
range from the traditional mechanical units to
those in which retention and stabilization is
provided by magnetic forces.

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• Stud attachments are particularly useful may
have be divided into those extra radicular and
projects from a diaphragm on root preparation
and those that are intraradicular applies loads
with in the root contour.
• The advantage of intraradicular attachments are
–less vertical space is occupied by the
attachment.
• Employing attachments adds to the expense of
the restoration and felt that the load distribution
to the abutments might not be so favorable
through the attachments.

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• Attempting to seat oversized casting will
result in vertical fracture of the root where
as undersized castings result in less
retention.
• Laboratory produced dowels are indicated
for the unusual shape or angled roots .but
the problems and difficulties cannot be
underestimated.

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ATTACHMENT SYSTEMS
• Stud attachments are simplest among the all
attachments.
• The male part consists of stud shaped projection
soldered to the diaphragm of dowel retained.
• The female part fits over the male unit &
embedded within the denture base of the
prosthesis.
• They are relatively small they can provide
additional retention,stability &support.
• In inadequate vertical space,less bone support of
the root these dome shaped copings are
recommended. www.indiandentalacademy.com

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• They are of two types :
• 1.Extra radicular:-in which male elements
projects from the root surface of the
preparation.
• 2.Intra radicular:-in which the male element
form the part of the denture base & engages
a specially produced depression with in the
root contour. www.indiandentalacademy.com

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SELECTION OF THE ATTACHMENTS:
• The rigid units,due to their small size are not
entirely immovable ,other units frequently allow
more movement than should be ever required.
• Extra radicular stud attachments are relatively
strong and can also provide retention than intra
radicular attachments.
• Larger the attachments are relatively stronger
than smaller ones and less prone to wear.
• The space availability will govern by the attachment
selection.

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• The rigid units allow a neat good looking and
retentive restoration to be made where four or
more widely spaced and abutment remain.
• Cylindrical stud attachments produce tipping
action on the abutments.
• Ball and socket attachments are started to
produce four times more tipping action than the
cylindrical attachments.
• Extra bracing of the roots may obtained by
connecting them.
• The leverage effect of the root must be an
important factor.

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NUMBER OF THE ATACHMENTS.
One stud attachment on each side of the arch will
usually suffice ,other remaining roots can be
covered with simple copings.
Increasing the no.of the attachments in a denture
does not produce the corresponding
improvement in the retention,it may contribute
to improved stability,but this leads to weaken
the prosthesis.

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CONNECTING ADJACENT COPINGS
• Two stud attachments on adjacent roots are
seldom necessary.
• They would serve only weaken the
prosthesis,complicate the plaque control.
• By this method rotational loads will be well
resisted and the inclined forces resolves in the
axial direction.

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--
• The connection between the two copings will
need to be planned with some care.
• The contours of the connection should be self
cleansable.
• It should not impinge on the tissues.
• This type of the attachment system particularly
useful hen the level of the adjacent margins are
about equal and there is at least 2-3mm
between the roots.

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DIFFERENT ATTACHMENT SYSTEMS
• DOLBO SUTD UNITS.
• The Dalbo ball &socket device is extremely popular it
combines neatness &strength.
• They are of different types:
• Ball &socket
• The rigid Dalbo attachment.
• The Dalbo ball &socket is the simplest of all series
• It is 4mm height.
• It allows limited vertical &rotational movements.

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• It has spherical shaped male section that is
easy to clean.
• The fingers of the socket is surrounded by
nylon ring that simplifies the adjustments.
• In this series female units need simply be
buried in the acrylic resin.
• Adjustments are easy to carry out and wear of
the male unit seen if it is incorrectly aligned.
• The retention of the unit can be increased by
altering the position of the lamellae.
• Adjustments can be done with the special
adjusting tool. www.indiandentalacademy.com

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• The adjustment tool has retractable spring
loaded plunger that fits the internal aspect of
the attachment.
• As the instrument is pressed down onto the
attachment lamellae squeezed inwards
• This procedure carried out carefully to avoid
the subsequent fracture of the prosthesis.

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THE COMPACT UNIT
• The Compact unit is another mall unit.
• The over all height is 2.85mm but the diameter
of retention knob is 2.8mm.
• Divergence upto10 degrees has been permitted
between two attachments.
• The female section incorporates 8 lamellae that
provides adjustable retention.
• The lamellae are protected by plastic sleeves.

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BATTESTI UNIT:
• The male unit is splits and incorporates the adjustment
for the retention.
• The male unit can be removed from the base &can be
replaced.
• This allows a comparatively neat female unit and
reduce the overall diameter[2.3mm] if the attachment.
• Three types of the designs are made.
• Two allows vertical translation & one is ball &socket
attachment.

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THE CONOD UNIT:
• The Conod rigid unit available in three
heights,also incorporates split male section.
• This allows the diameter of the attachment to
2.4mm.
• Split male unit require special instrument for the
adjustment.m

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BARR &FAH UNITS.
They are rigid and require little vertical space.
However it is the unit with rounded male section
2.2mm tall that requires the least space.
They require alignment and positioning
procedures similar to other stud attachments.

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CEKA SYSTEM
• This system available as rigid and resilient
attachments.
• Both share the common base but different female
section.
• The space required for the CEKA system is 1.4mm
PLACEMENT OF THE ATTACHMENT STP BY STEP
PROCEDURE:
-the spring pin is removed from the unit special mandrel
is attached.
-insert the mandrel into the attachment base.
-align the base on the coping connect with the sticky
wax www.indiandentalacademy.com

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•
CEKA SYSTEM.
• This system available as rigid and resilient
attachments.
• Both share the common base but different
female section.
• The space required for the CEKA system is
1.4mm

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• Locating instruments are available to place the
base of the attachment onto the coping.
• Insert the locating pin into the screw base .
• Investment is placed around the dowel and
coping.
• Solder the attachment base &the co[ping.
• After the soldering attachment screw into the
base forms the part of the coping.
• Align the attachment base in the coping wax.

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ROTHERMANN UNIT:
• The Rothemann unit requires little vertical space.
• It is available as rigid & resilient units.
• The overall height of the unit is 1.1mm &1.7mm for
the resilient unit.
• The Rothermann unit is button shaped unit the male
has the groove .
• The female section slides over the tapered edge of
the male, with free ends of the female engages the
deepest retaining groove.
• The female section is designed to retain by the
• acrylic resin.

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• Apart from the little vertical space
requirement this is particularly useful in
tilted teeth.
• Like most other stud attachment, adequate
bulk of the acrylic is essential around the
attachment.

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GERBER UNITS
• Available as 2 types of units –rigid &resilient.
• Each of these available in two sizes.
• The larger of the resilient unit is 5.2mm
&shorter one is 4.4mm.
• The retention of the both types of the Geber
is obtained by retaining spring.

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O-SO SYSTEM
• The system comprises of Vitallium male stud
incorporating its own dowel.
• No conventional female is required in the
denture,instead a rubber ring is incorporated .
• This arrangement results in saving of space
&cost.the total space required is 3.2mm.
• There will be excessive wear of the attachment with
excessive divergence.
• The hemispherical head of the male unit permits
ball &socket rotation &includes a pressure relating
groove to simplify the seating of the denture

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CLINICAL STEPS:
• The Endodontically treated roots are reduced to
gingival level.
• Use carbide burs(no.700) to prepare pilot hole to depth
of about 6mm following center of the root.
• Then the hole is enlarged with round carbide bur.
• After the preparation has made,the zero degree male
units are tried ,ensuring that they seat correctly.
• Depend upon the contour of the edentulous ridges the
units are selected whether to use parallel attachments
angulated attachment.
• During processing a void should be left over each root
to allow the male &eventual ring component of the
attachment that will be placed later on.

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HOWMEDICA AND INOUE UNITS
• Howmedia has the plastic dowel form with around
head known as micro ring system.
• The plastic pattern is incorporated in the wax up of the
root face restoration.retention is provided by small ring
that engages the depression under the stud.
• Another attachment system employing an ‘o’shaped
rubber retaining element is produced by Inoue
attachment.
• Four sizes of the plastic patterns are produced &can
be incorporated in wax up of the root restoration.

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• A small measuring device to help with
planning vertical &Buccolingual space
comes with the kit and the unit can be cast
in the material of choice.
• Intra-oral location procedure of the rubber
ring are normally recommended.

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• The other two new comers to the field
has been produced by WHALEDENT
&DR.KURER stud attachments.

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INTRA RADICULAR STUD ATTACHMENT:
• ZEST ANCHOR ATTACHMENT:
• The nylon male is incorporated in the denture
base & projects downwards,engaging the
recess in the root preparation.
• The design reduces the vertical space
requirement &imparts the strength of the
denture.
• The loads that are applied at a point that is
well apical to the gingival margin of the root ,a
feature that is impossible to achieve with
conventional projecting attachment.www.indiandentalacademy.com

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• Available in two sizes:
• depend upon the root length
• depend upon the diameter .

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• Vertical space requirement are similar to those of
Rothermann unit.
• This particular attachment system can be employed
for the root preparation without laboratory work.
• STEPS INVOLVING:
• The abutment on the master cast are cut down to
1mm above the gingival margin.
• No.42 drill used to prepare the hole in area
corresponding with the center 0.of the root .
• Red spacer plugs inserted into the prepared
abutment &denture waxed up round them.

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• This spacer acts as a guide to attachment
that will be replaced later on.
• With the spacer the denture is processed
and remount on the articulator & check
the occlusion.

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The mutual repulsion system has paired
bar magnets with like poles adjacent
&cured into maxillary &mandibular
complete dentures.
When magnets were at or near tooth
contact the repelling forces exerted a
seating effect on both dentures.
The disadvantage of this system is the
repelling forces rapidly decreases when
jaws are widly separated.
The constant forces increases the ridge
resorption.

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•Mutual attraction of unlike forces:-this
system used mainly in sectional dentures,
obturators&multi component maxillofacial
prosthesis.
•In this system the magnets are placed in
denture &underlying soft tissue.
•Continuous attracting forces could cause
the embedded bar magnets move through
the bone erode the soft tissue &become
exfoliated. www.indiandentalacademy.com

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•Magnets used:-the most commonly used
magnets are rare earth cobalt(REC); cobalt
samarium(Co-Sm).
•They are short magnets,2mm long or even
less.
•The magnetic forces they exert is more
than 100grms.
•In case of over dentures,the magnets are
placed in the roots &impression surface of
the over denturewww.indiandentalacademy.com

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•Dislodging forces which exceeds the retention
forces unseat the denture.
•The clinical & technical procedures used to
insert the magnets are simple.
•There are no path of insertion restriction and
thus specialized instruments that are required for
precision attachments are not necessary.
•Disadvantages:-the small root face of the
supporting roots limit the size of the magnet that
can be used,there by limits the retention
provided.

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•The magnetic alloy can erode &fracture in
the mouth.to eliminate this problem they are
coated with silver amalgam or they will be
electroplated.
•The thickness of the protective layer also
reduces the magnetic effect and there by
retention.
•Finally unavoidable magnetic field
surrounds both intra radicular &denture
magnets. www.indiandentalacademy.com

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118
•BIOLOGICAL EFFECT OF THE MAGNETS:
•There could be physical effect because of the presence
of magnetic field gradient.
•There might be chemical effect because of the alloy it
self.
•COPARISION OF THE MAGNGETS & PRECISION
ATTACHMENTS :
•Magnets are simple low cost,self adjustable,inherent
stress breaking,automatic reseating after denture
displacement.
•No special tools are required for the adjustments.www.indiandentalacademy.com

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MAGNETIC RETENTION SYSTEMS:
• 1.CEMENTED IN KEEPER SYSTEM.
• 2.SCREWED IN KEEPER SYSTEM.
• 1.cemented in keeper system:a shallow oval
shaped cavity is prepared on the root face of
the & a preformed magnetisable disc 5mm
long, 3.2mm wide 1.2mm thick cemented into
the cavity.
• The root face magnet surface attaches with
retentive element.

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• The other face slightly rounded edges which
inserted in the root face cavity.
• Two magnetic retention units per denture will
provide the adequate retention ,but three or four
evenly distributed around the mouth gives better
retention &stabilityif more than that patients feel
difficult to remove the denture.
• PROCEDURE: Prepare the root face flat &level
with gingival margin.
• The root faces are trimmed so,that more or less
right angles to the long axis of the root.

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• Enlarge the canal with round bur penetrates the root
canal to the depth of about 3mm.
• Select the size of the attachment.
• The root face cavity should be cut to the largest size
with out lateral root perforation.
• Check the fit of the system.
• Any cement which is relatively insoluble and abrasion
resistant can be used to hold the keeper in the root
cavity.
• The keeper is then inserted using handle with light
finger pressure is applied until the cement reaches the
initial set.

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• SCREWED ON KEEPER SYSTAEM:
• Specially used on root where further root canal
treatment may be required (or) reduction in root height
may become necessary because of anticipated
gingival recession or mucogingival surgery is required.
• The screwed on system is cone shaped counter sunk
holes which pass the two self threading pins used to
hold it against the root face.
• The system covers 50% more of the root face than
does cemented in keeper system.
• This does not require large root face

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• The screwed on system adds 1.2mm to height of the
root face.
• The clinical root preparation is same as cemented in
keeper system.
• The prefabricated keeper is trail fitted to the root face to
verify that close contact between the matting faces has
been achieved.
• The keeper is held in the position with the help of the
probe .
• The holes are prepared of self threaded pins.
• After the holes has been prepared,self threading pins
have been screwed against the root face.

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BAR ATTACHMENTS.
• Bar attachments are those attachments allows the
movement between the components.
• Their application in the over dentures construction
where 2 or 3 teeth are remain.
• The bar is usually attached to the root filled teeth
locking the roots together &improving the crown root
ratio.
• The bar joints are subdivide into two groups:
• 1.single sleeve bar joints.
• 2.multiple sleeve bar joints.

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SINGLE SLEEVE BAR JOINTS:
The bar has been produced from wrought wire
pear shaped in cross section running between the
abutments &just contact with the oral mucosa.
Two sizes of the Dolder bar joints are produced
With heights of 3.5mm &4.5mm.
Sufficient bulk of the acrylic resin must cover the
sleeve to prevent the fracture.
The original aim of the DOLDER joint was to
allow considerable amount of the vertical &
rotational movements & rotation around the long

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• As a single sleeve bar it has to run straight ,it cannot
follow the anteroposterior curvature of the ridge.
• Where ever possible the bar should be aligned
perpendicularly to the line bisecting the angle between
the two lines drawn along the crest of the posterior
edentulous ridges.
• Where the arch is markedly curved ,that may occupy
tongue space so that, it is better to select another
attachment system.
• In marked irregularities of the soft tissue mucosa
&mucogingival areas preliminary minor surgery give
batter results.

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• Where a large depression is involved the bar
can be connected into it with two connecting
elements& there by reduces the space
occupation.
• Where there are just two teeth & roots on the
same side ,such as canine & molar the bar
joins two roots& thus run parallel to the
edentulous ridges.
• The thickness of the bar is cannot be less
than 2mm.

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MULTIPLE SLEEVE SYSTEM:
Several short sleeves are substituted .
There is no need to the bar to run straight, it can be bent
to follow the vertical contours as well as antero
posterior curvature of the ridge.
This simplifies the plaque control.
The sleeves can be placed at convenient location of the
denture.
The bars in the circular cross section is the most
versatile as it can be bent into all planes.
The rigid bars are available in the oval cross sections.
The tags in the bars resist the rotational movements of
the denture.

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IMPRESSION PROCEDURES
Locating procedures before denture construction.
locating procedures after denture construction.
Locating procedures before denture construction:
1.all in one procedure.
2.Completing metal work of restoration before overall
impression.
3.Transfer coping technique.
Locating procedures after denture construction:
Intra oral &extra oral processing technique.

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All in one impression:
• This procedure is particularly useful root
surfaces to be left bare, rather than covering
with precious metal coping.
• The recommended material for this technique is
Zoë.
• The all in one procedure is not usually suitable
for when copings or root preparation to be
made as sectioning of cast that is required to
produce individual dies

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Completing metal work
• Particularly useful when individual precious metal root
copings are to be constructed.
• When attachments are concerned,the method is
modified.it is even more important to ensure that
pathof insertion of the denture to be clearly marked in
the master cast before any metal work is completed.
• The unpolished restorations are placed on their
respective roots checked for the accuracy,bbut not
cemented.
• The metal restoration are now transferred to the
impression

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• The dies are produced &placed on their
respective castings and a master cast made on
which the denture eventually constructed.

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Transfer coping technique:
• The procedure allows the operator to
concentrate in each individual root preparation.
• Impression is placed in copper band is usually
employed for the impression technoque with
stainless steel dowel or resin pattern to give an
accurate impression of the root canal.
• A copper plated die is produced & this die
transfer copings are constructed.
• Transfer copings are placed on each of the
preparation when operator has determined that
they seat accurately.

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• Special tray is used for the impression
procedure.
• The dies are placed in the respective
places &impression is made.
• The dies are transferred to the impression
from which master cast is produced.

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INTRA ORAL PROCESSING
• In this procedure the removable section of the
attachment is connected to the over denture in the
mouth with self polymerizing resin.
• A vent is placed on the lingual surface of the
denture&attachment is placed in proper
location.the self polymerizing resin is used to
attach the female section in the denture.The
excess material will be flown out through the
vent.

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