Radiographic template fabrication
- 1.Review the acquired CBCT record by using a 3-dimensional viewer (Planmeca Romexis Viewer, v2.3.0.R; Planmeca Oy, Helsinki, Finland) to make a thorough assessment before implant placement.
- 2.Orient the image so that the vertical plane is perpendicular to the axis of the ridge for optimal accuracy when measuring available bone dimensions for implant placement. For treatment planning purposes, move the cross-sectional slices in 3 different planes (sagittal, vertical, and horizontal) as follows: Displace the sagittal and vertical planes on the viewer so that they intersect at the site of the prospective implant, which coincides with the radiopaque marking of the Ca(OH)2 ribbon. Place the horizontal plane at the level of the mental foramen to evaluate the distance between the prospective implant site and the mental foramen (Fig. 3).
- 3.On the vertical cross-section, determine the available bone height and width as well as the restorative space, which is represented by the distance between the crest of the residual ridge and the most coronal Ca(OH)2 radiopaque marking (Fig. 4).
- 4.Determine the buccolingual angulation of the implant bed in relation to the alveolar contour. Based on this information, determine how much crestal alveolar bone reduction is necessary to accommodate the minimal restorative space needed for the prosthetic rehabilitation. For example, note that a Straumann Tissue Level Standard Plus Implant (Institut Straumann AG, Basel, Switzerland) with a Locator (Zest Anchors Inc, Escondido, Calif) attachment incorporated in a mandibular overdenture requires a minimum of 7.3 to 8.3 mm (1.8 mm of smooth implant collar, 1 mm for the soft tissue collar built into the Locator abutment, 2.5 mm height of denture cap which includes the patrix Locator attachment, and 2 to 3 mm of acrylic resin).
- 5.Finally, by using the shape of the alveolar ridge as a reference, determine the appropriate angle of the implant bed preparation in the buccolingual dimension. As an example, note that Figure 4 illustrates that the axis of the implant bed will be parallel to the lingual cortical bone.
- 6.If needed, displace the site of the implant osteotomy based on the anatomy observed on the CBCT record, and then measure this displacement in relation to the radiopaque reference marking.
- 1.Use the patient's mandibular denture to transfer the location of the radiopaque markings (distal line angles of the canine) used during the CBCT acquisition. Mark these sites in the intaglio of the mandibular denture with a color transfer applicator (Dr Thompson's Color Transfer Applicators; Great Plains Dental Products Co Inc, Kingman, Kans) (Fig. 5).
- 2.Reposition the denture intraorally with slight pressure to impress the mucosa with the reference point markings from the prosthesis intaglio (Fig. 6).
- 3.Incise the mucosa and slightly elevate a mucoperiosteal flap to mark the alveolar crest with a small round bur at the sites where the mucosa has been impressed. Alternatively, if the site has been displaced during the CBCT-based treatment planning, mark the alveolar crest at the desired distance, taking the color marking on the mucosa as a reference point (Fig. 7).
- 4.Elevate a full thickness flap before proceeding with alveoloplasty, implant bed preparation, and placement according to the predetermined length, diameter, and angulation (Fig. 8).
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