Methods:
An impression of the maxillary denture was made extraorally using
alginate and a Lang denture duplicator (Lang Dental, Wheeling, IL) to
allow fabrication of a diagnostic guide to be utilized with a CBCT in
the planning phase of treatment. The patient was dismissed and appointed
to return for the CBCT.
Lucitone acrylic was mixed and poured into the duplicator. Upon setting
the duplicate denture was removed and any marginal flash was removed
with an acrylic bur and polished. (Figure 1)
Holes were drilled through the center of the convexity of the tissue
surface through the cingulum of the oral surface of the anterior teeth
and the central fossa of the posterior teeth of the duplicated denture
with a 3/32nd drill. In the proposed sites 2 mm guide
sleeves were placed in the holes of the teeth of the duplicated denture.
The patient returned and the duplicate diagnostic denture with the 2 mm
guide sleeves was inserted intraorally and the CBCT was performed. The
patient was again dismissed, and an appointment was scheduled for the
surgical phase of treatment.
The CBCT was imported into the planning software
(InvivoTM 5, Osteoid, Santa Clara, CA). The treatment
plan was to place four implants spread around the arch to retain a new
prosthesis with Atlantis Conus frictional fit abutments (Dentsply
Sirona, York, PA) in the implants and corresponding caps embedded in the
prosthesis. Analysis of perspective sites at tooth numbers 3, 4, 5, 6,
8, 10, 12 and 13 were selected based on a preliminary review of the
initial CBCT and the position of the available bone and its relation to
the maxillary sinuses bilaterally.
The maxillary right first molar site (#3) was analyzed, and it was
determined insufficient crestal height was present inferior to the sinus
floor and would require sinus augmentation to permit implant placement
at that site. However, the patient preferred not to have the sinus
elevation. (Figure 2)
The maxillary right 2nd premolar site (#4) was
analyzed, and sufficient bone was noted for implant placement. (Figure
3)
The maxillary right 1st premolar site (#5) was
analyzed, was selected for placement of a fixation screw for the full
arch surgical guide and sufficient bone was present to accommodate a 17
mm screw. No angle or linear corrections are needed. (Figure 4)
The maxillary right canine site (#6) was analyzed, and sufficient
height was noted for implant placement. (Figure 5)
The maxillary right central incisor site (#8) was analyzed, and
sufficient bone was noted for implant placement without perforation of
the nasal floor. (Figure 6)
The maxillary left lateral incisor site (#10) was analyzed, and
sufficient bone was noted for implant placement without perforation of
the nasal floor. However, a 15˚ angle correction is necessary to place
the implant as planned. (Figure 7)
The maxillary left 1st premolar site (#12) was
analyzed, and sufficient bone was noted for implant placement. (Figure
8)
The maxillary right 2nd premolar site (#13) was analyzed, and
sufficient bone was noted for implant placement. (Figure 9)
A decision was made for each site whether or not it was suitable for
implant placement.
The scan data was imported into planning software
(InvivoTM 5) and each potential site was analyzed.
Site #3 was analyzed, although adequate width buccal-palatal was
present, insufficient crestal height was present that a crestal sinus
lift would be required to allow an implant to be placed at this site.
(Figure 2) It was decided based on that information that this site would
not be used for implant placement. Site #4 was then analyzed, and it
was determined sufficient crestal height and adequate ridge width was
present buccal-palatal to allow implant placement. A 4.8 x 9mm Astra EV
implant was selected for this site with no correction required in the
buccal-palatal or mesial-distal directions. (Figure 3) Site #5 was
decided that implant placement would not be at this site but a fixation
screw would be placed to stabilize the full arch edentulous surgical
guide and there was sufficient bone present to accommodate the screw
without contact anatomical structures (maxillary sinus). (Figure 4) Site
#6 was next analyzed, and it was determined that no angle correction
would be needed at this site. A 4.2 x 11 mm Astra EV implant was planned
for the site following 5mm crestal ridge reduction (Figure 5) Site #8
was determined to accommodate a fixation screw for the surgical guide
and following analysis a 1mm offset correction would be needed to avoid
the incisive canal. (Figure 6) Site #10 was analyzed and an angle
correction to the buccal of 15 degrees would be required as well as
crestal bone reduction of 5-6mm would be needed due to the thin crestal
ridge. A 3.6 x 10 mm Astra EV implant was planned for this site. (Figure
7) Site #12 was planned for a fixation screw and analysis determined no
angle correction would be needed. (Figure 8) Finally, site #13 was
analyzed and no correction was required at this site to accommodate an
implant and a 4.8 x 8mm Astra EV implant was planned for this site.
(Figure 9) The final plan was for placement of implants at sites #4, 6,
10 and 13 with fixation screws at sites #5, 8 and 12.
A putty base was created in the diagnostic guide using a 2-part hard
setting polysiloxane material (Coltene Whaledent, Cuyahoga Falls, OH).
Guide posts (2 x 30 mm) (DePlaque) were inserted through the guide
sleeves in the diagnostic guide at sites #4, 5, 6, 8, 10, 12 and 13
before the putty base had set. (Figure 10) Following setting of the
putty base, the guide posts were removed, and the diagnostic guide was
separated from the base. The 2-piece lower-part straight, offset and
angle corrected guide posts were inserted into the 2 mm holes in the
putty. (Figure 11 left) An acrylic bur was used to make indentations in
the putty base so the rectangular base of the guide posts were flush
with the tissue level. 2-Piece lower-part guide posts replacing 2 mm
straight guide posts for the planned sites for implants and guide
fixation screws were placed into the putty base at the sites #4, 5, 10,
12 and 13 previously occupied by the 2 mm guide posts. A 2 mm offset
lower-part of the 2-piece guide post was placed at site #6 with the
offset positioned to the distal to even out the spacing. At site #8 a 1
mm offset lower part of the 2-piece guide post was placed in the putty
base. An angle correction was required at site #10, this was
accomplished with the Guide Right bending tool (DePlaque) (Figures 12
and 13) and the corrected guide post was inserted into site #10. (This
completed the base to fabricate the corrected surgical guide. (Figure 11
right) The 3 mm upper-removable-part of the 2-piece guide posts were
placed onto the lower-part of each guide post to position the 3 mm in ID
guide sleeves (Figure 14) that were to accommodate the 3 mm depth stop
drills that will be utilized at surgery. (Figure 15)
The holes in the duplicate of the denture were enlarged to allow it to
seat over the guide posts and their sleeves on the putty base. Primotec
LC gel (Primotec USA, Norwalk, CT) was placed to fixate the guide
sleeves to the duplicate denture and then light-cured to complete the
corrected surgical guide. (Figure 16)