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)