(800) 854-7256 Main  |  (855) 289-9657 Case Pickup  |  New Customer  |  My Account NEW
?php get_header(); ?>

Screw-Retained BioTemps® Bridge

hs-sae-kim

by Sae Kim, Production Manager, BioTemps Department


In the presence of sufficient implant stability, temporization affords a wide array of benefits. In addition to providing the patient with a lifelike prosthesis while the implant osseointegrates and the soft tissue heals, temporaries help establish an ideal emergence profile and esthetic gingival contours and margins for the planned restoration. Provisionalization also gives the patient an opportunity to verify the fit and esthetics of the proposed prosthesis, providing clinicians with an extra measure of certainty.

Another option finding favor among practitioners is the screw-retained restoration, which eliminates the need for cement cleanup while easing prosthetic retrieval and maintenance. Screw-retained crowns are also beneficial when there is limited interocclusal space, facilitating implant therapy for cases in which such treatment might otherwise be contraindicated. Fabricated from layered poly(methyl methacrylate) (PMMA), BioTemps® Provisionals (Glidewell Laboratories; Newport Beach, Calif.) provide the ideal pathway to a well-fitting, esthetic screw-retained restoration.

The versatility of CAD/CAM technology and layered PMMA means this approach can be adopted whether a single-tooth, multi-unit or full-arch case is being restored. Following a 5-unit screw-retained BioTemps bridge through the various stages of laboratory production demonstrates the means through which this treatment protocol ensures an ideal prosthetic outcome for the final restoration.

The Process

To begin the process, the lab produces a working cast that will serve as the basis for determining the prosthetic design of the BioTemps provisional, including analogs that represent the position of the implants and a soft-tissue model that replicates the patient’s gingival anatomy (Fig. 1). The working cast is mounted on the articulator along with the opposing model and checked to ensure an accurate interocclusal relationship (Fig. 2).

im0603-screw-retained-01

Figure 1: Working cast with soft-tissue material.

im0603-screw-retained-02

Figure 2: The working model is articulated with the opposing cast to check the bite before moving forward with the fabrication process.

After verifying the bite, the models undergo a series of scans to generate the digital information needed to determine the CAD design for the screw-retained temporary bridge. For the first of three scans, the soft-tissue material is removed from the working cast, and scanning abutments are attached (Figs. 3a, 3b). The scanning abutments convey the precise positions of the implants for incorporation in the virtual model that will be used to design the BioTemps restoration (Fig. 4). The scanning abutments are then removed and the soft-tissue material is replaced so the second scan can be taken (Fig. 5). This produces the data needed to design a prosthesis that conforms to the patient’s gingival anatomy and establishes esthetic margins. Lastly, the working cast and opposing model are mounted and scanned together, capturing the interocclusal relationship (Fig. 6).

im0603-screw-retained-03a

Figures 3a, 3b: The model is prepared for the first of three scans by removing the soft-tissue material and attaching scanning abutments to the implant analogs.

im0603-screw-retained-03b

Figures 3a, 3b: The model is prepared for the first of three scans by removing the soft-tissue material and attaching scanning abutments to the implant analogs.

Figure 4: The working cast is first scanned with the scanning abutments in place and no soft-tissue material.

im0603-screw-retained-05

Figure 5: The second scan includes the working model with soft-tissue material.

im0603-screw-retained-06

Figure 6: The third and final scan creates a virtual representation of the bite from the articulated models.

A specially trained technician utilizes dental CAD software to design the screw-retained BioTemps bridge on the virtual model generated from the scans. The prosthetic teeth are selected from a digital crown library, including three screw-retained units and two pontics. After the crowns are selected, the design software generates an ideal tooth form for each individual unit of the bridge, and the technician positions the units on the virtual model (Figs. 7a, 7b). The margins are defined and verified, and the restorative design is determined, including the size, shape, dimensions, and interproximal and opposing contacts for the five adjoining crowns of the temporary prosthesis (Figs. 8a, 8b).

im0603-screw-retained-07a

Figures 7a, 7b: The five crowns of the BioTemps bridge are selected from a virtual library and positioned on the digital model so the prosthetic design can be determined.

im0603-screw-retained-07b

Figures 7a, 7b: The five crowns of the BioTemps bridge are selected from a virtual library and positioned on the digital model so the prosthetic design can be determined.

im0603-screw-retained-08a

Figures 8a, 8b: The width, height, contours, contacts and bite of the 5-unit BioTemps bridge are fine-tuned and verified using advanced CAD software.

im0603-screw-retained-08b

Figures 8a, 8b: The width, height, contours, contacts and bite of the 5-unit BioTemps bridge are fine-tuned and verified using advanced CAD software.

A specially trained technician utilizes dental CAD software to design the screw-retained BioTemps bridge on the virtual model generated from the scans.

Next, the locations of the access holes for the titanium copings are determined. The data generated from the scanning abutments is essential in positioning the openings in alignment with the implants (Fig. 9). The access holes are created with the proper dimensions needed to accommodate the titanium copings and are situated to ensure a passive fit of the prosthesis (Figs. 10a, 10b).

im0603-screw-retained-09

Figure 9: The information obtained from the scanning abutments helps ensure access holes that align with the implant positions.

im0603-screw-retained-10a

Figures 10a, 10b: Using digital representations of the titanium copings, access holes are designed through which screws will be inserted to attach the prosthesis to the implants.

im0603-screw-retained-10b

Figures 10a, 10b: Using digital representations of the titanium copings, access holes are designed through which screws will be inserted to attach the prosthesis to the implants.

The data generated from the scanning abutments is essential in positioning the openings in alignment with the implants.

After confirming the prosthetic design on the virtual model, CAM files are generated and sent to the milling center for fabrication of the screw-retained temporary (Figs. 11a–11c). A layered PMMA disc is attached to the mill, and the temporary restoration is milled, creating an exact physical duplicate of the CAD design (Figs. 12a, 12b). The technician removes the prosthesis from the disc using a handpiece (Figs. 13a, 13b).

The BioTemps bridge is touched up using a bur and disc to ensure lifelike esthetics (Figs. 14a, 14b). Titanium copings are seated in the access holes of the provisional, which is then attached to the working model to verify the accuracy of the milled prosthesis (Figs. 15a–15c). After making any needed adjustments, the screw-retained bridge is cleaned in preparation for the staining and glazing process (Fig. 16). If necessary, stain is applied to match the shade requested by the doctor. The prosthesis is then glazed and light-cured (Figs. 17a, 17b). Lastly, the titanium copings are cemented into the openings of the finished BioTemps bridge (Fig. 18).

With the fabrication process complete, final QC is performed to ensure an accurate bite, margins, shade, contours and adherence to any special instructions provided by the doctor (Figs. 19a, 19b). The BioTemps bridge is sent to the doctor for patient try-in and can be worn for an interim to ensure the patient is satisfied with the function and esthetics of the prosthetic design (Fig. 20). The CAD file is updated with any necessary modifications prior to milling of the final screw-retained bridge, resulting in an extremely accurate restoration.

Conclusion

The screw-retained BioTemps bridge is produced using a combination of cutting-edge CAD/CAM technology and traditional lab fabrication techniques. The result is a natural-looking, durable prosthesis that can serve as a temporary restoration for the duration of healing while establishing ideal gingival contours for the planned screw-retained restoration.

Note: Clinical dentistry and images in Figure 20 courtesy of Siamak Abai, DDS, MMedSc

Inclusive Magazine: Volume 6, Issue 3

Subscribing Has Its Perks!


Offers on products you may already use
Introductory offers on new products
Educational materials