What is a Precision Attachment?
A precision attachment is a precision-machined male and
female (key and lock) housing that connects a removable partial
denture to fixed bridgework in cases where the fixed bridgework
is not possible.
What are the Advantages of Precision Attachment
Precision attachment partial dentures are the very best
restorations where fixed restorations are contraindicated.
Several key advantages of this type of restoration:
• Cosmetic Appearance, avoids the need for unsightly
• Maintainable Periodontal Health
• Longevity of Abutment Teeth
• Patient Comfort
• Questionable Teeth can be saved in a way that does
not affect the case
• Longevity if they are lost in the future.
• Natural Tooth and/or Implant Abutments can Be Used
• Precision Attachment Partial Dentures Can Be Adapted
to Compensate for Future Changes in the Mouth
• Prevent bone resorption of the ridges under the partial
• Confer the highest degree of patient comfort.
Even though there are no locking mechanisms, a good precision
attachment partial denture will not dislodge during normal
function. The reason the partial denture does not continually
fall out is because it is surveyed in two directions so that
the path of insertion is different from the pull of the muscles
and the action of the tongue and gravity. Although the partial
cannot be dislodged during function, it can move in a vertical
direction slightly to release the forces instead of passing
along these forces to the abutment teeth. The result is physiologic
stimulation of the abutment teeth and the edentulous ridges.
Clinical experience has shown that this physiologic stimulation
results in increased longevity of the abutment teeth, even
when a few teeth are required to carry the load of an entire
arch. The stimulation of the edentulous ridge also prevents
the bone resorption that typically reduces tissue support
for the partial denture. The tissue under a well-fitting precision
attachment partial is typically healthy and firm. There is
surprisingly little wear of attachments that are used in this
manner, even after many years of function! While the prosthesis
may require relining or alteration of the occlusion to compensate
for changes, it is rarely necessary to adjust or replace the
attachments on the partial. The partial denture is never kept
in a glass overnight. It is worn 24 hours a day to prevent
collapse of the musculature and the occlusion and only removed
for cleaning and hygiene.
Implants are sometimes used to retain a full denture if not
enough implants can be placed to create a full arch of fixed
bridge work. However, implants are quite strong and have been
used successfully to support precision attachment cases for
over 14 years. Because precision attachment cases work so
well on the weakest teeth imaginable, they work exceedingly
well on implants, which are usually strong.
An implant- supported precision attachment partial denture
is far superior to an implant-supported full denture for the
• Superior Comfort and Self-Esteem. The posterior bar
can be made thin and only covers a small area of the palate,
while a denture usually covers the entire palate. The patient
wearing an attachment case has anterior (front) teeth that
do not come out, unlike the patient wearing a denture. He
or she doesn’t feel bad looking in the mirror when removing
a partial denture for hygiene.
• Superior Function. Unlike a denture, the posterior
bar of an attachment case frees the tongue for normal speech
and allows taste buds on the anterior palate to function normally.
An attachment case doesn’t have the anterior-posterior
movement that an implant supported denture might have. Patients
with an attachment case on implants can bite into anything.
This may not be possible with any type of denture.
• Increased Longevity. A precision attachment case does
not place lateral forces on implants, which can be destructive
to implants as well as natural teeth. Implants are not indestructible
and if overloaded they can fail. A denture connected to implants,
however, is usually locked in place.
• Patients Avoid Wearing Dentures. A denture that rests
on tissue can only exert 10 to 15% of the force of a patient
with natural teeth. Although the placement of implants may
make wearing a denture easier, most people don’t want
to go through the surgery and expense unless they are going
to get rid of the denture. Patients who wore an attachment
case prior to wearing a denture know the difference between
the two, and they are thrilled that they can have the same
exact case on implants.
• Both Natural and Implant Abutments Can Be Used. Single
posterior teeth that remain from a previous attachment case
can be left intact, and used as part of the new attachment
case! Unlike fixed bridgework, a precision attachment partial
denture can link both implant and natural abutments because
of the stress-breaking action of the attachment case.
• Patients Choose Implants to Avoid Wearing Dentures.
Implants can usually be placed in the upper and lower anterior
regions of the dental arches. The placement of just three
implants is enough to make a fantastic attachment case—an
anterior fixed bridge and a precision attachment posterior
A common misconception is that implants make precision attachments
dentures obsolete. The rationale for using implants with attachments
is that placing enough implants for a full arch of fixed bridgework
may not be possible for the following reasons:
• Anatomical Problems: Most of the anatomical problems
encountered for placing implants are in the posterior regions
of the mouth. Inadequate bone under the sinus (upper arch)
or above the mandibular nerve (lower arch) may make it impossible
to place implants of adequate length to support fixed bridgework.
• Bone Grafts: The prognosis for success is lower when
bone grafts are required for implant placement and the duration
of treatment is much longer. Candidates for these procedures
are patients who understand the risks and accept them in order
to have fixed bridgework.
• Bone Quality: The bone in some areas of the mouth
may have poor quality for the placement of implants. The lowest
quality bone is typically found in the upper arch-posterior
• Fixed Bridgework with teeth cantilevered may be inappropriate.
Studies have proven that four or five implants in the anterior
region can be used with cantilevers (unsupported teeth added)
to create a successful case.
Even though the cantilever fixed bridges work well with implants,
they may not be the best option if:
• Anatomical deficiencies prevent the placement of sufficient
implants to support fixed bridgework.
• The patient has been comfortable with an attachment
case in the past.
• The patient does not want too many implants placed.
Patients who do not want the extra surgery and expense of
multiple implants are very receptive to the placement of only
three implants to restore an entire arch.