Replacing a tooth to an existing RPD after an extraction allows
the patient to have an immediate esthetic replacement. If this can
be done immediately in the dental chair, then it eliminates the
need for an impression(s), a lab procedure, expense and a return
visit for the patient. An interim prosthesis will allow patient use
of the RPD while the extraction site heals. It can also eliminate the
need to make a new RPD if all esthetic and functional requirements
are fulfilled. Some form of retention will be needed to secure a
replacement denture tooth to the RPD. Existing clasps [1], adjacent
denture teeth [2], solder or laser welded retention [3], wire loops
[4] and simple undercuts have all been used to add or repair an
RPD. An endodontic post can add significant retention to a resin or
acrylic RPD. Use the endodontic post system drill to make a hole in
the RPD base. Place a thin film of light polymerizing gel (Triad) into
the drill hole before seating then securing (curing) the measured
and cut post. Placing two posts provides better retention.
The new flex type RPDs are not able to be repaired using
traditional repair resin. A screw type endodontic post system can
be used to create retention in a flex type RPD. (Figure 1) The threads
will engage the flex base material similar to dentin. Narrow and
short threaded post systems work better for this application. Nontreaded
endodontic posts can be placed in a Methylmethaculate
resin RPD base or adjacent denture teeth with a light polymerizing
gel to gain retention for addition of a denture tooth. (Figure 2) After
an endodontic post(s) are secured to a RPD, a matching denture
tooth can be relieved to passively fit over the post. (Figures 1 & 2)
It is important to ensure the correct orientation to esthetically and
functionally replace a missing tooth. The denture tooth can then
be positioned in the patient’s mouth to verify correct function and
esthetics. Ensure that adjacent tooth undercuts are not engaged
before curing. Once correct placement is confirmed the denture
tooth can be secured to the RPD over the endodontic posts with
light polymerizing gel and tissue colored repair material directly
(Triad gel and repair material) in the patient’s mouth. Trim and
polish. After the patient has healed the intaglio surface can be
relined and/or a new RPD can be made.
Figure 1: Treaded endodontic post in flex type RPD for retention element.
Figure 2: Non-treaded endodontic post in acrylic RPD for retentive element.