Prosthodontic Discussion

Dr. Lanny Levenson wrote " Could you show the steps in the fabrication of a stent for implant placement? I do wax ups and  send a thin "suck-down" stent to the oral surgeon but I would like to see the steps and how you go about the fabrication of the thicker style implant stent and how you handle implant angulation in your communication with the oral surgeon."

 

 Answer:

 

Great question! As you know, dental implant therapy should always be restoratively driven. Therefore, it is the restorative dentist that is responsible for the desired prosthesis and determining the implant location to coincide with the desired restoration. The desired restoration should always allow for co-localization of dental implant placement. The best way to communicate this desired implant placement to the surgeon is with the use of a surgical template. While there are many ways to fabricate a surgical template, they should follow several basic criteria.

-         Co-localize implant placement with desired restorative outcome taking into account the anatomical features of the implant site.

-         Stable and retentive on teeth

-         Able to be sterilized

-         Techniques applicable for the single tooth, multiple teeth, or completely edentulous patient

-         Can be used as a radiographic template

 

Follow these simple steps:

 

            1. Diagnostic waxing of desired restoration (Figure 1)

              

                 

                                                Figure 1

 

            2. Duplicate cast of desired restoration.

            3. Use a thermoplastic matrix on the cast of the desired restoration. Material should be 2mm-3mm in thickness to provide ridged support.   (Figure 2)

            

              

                                             Figure 2

 

            4. The matrix should be trimmed from the cast at the height of contour of the retentive teeth and maintain the entire outline for the desired restoration.

Recommended bur for trimming this thick material: Brassler 219 acrylic bur.

            5. Lubricate a cast that has the missing tooth/ teeth and fill the missing tooth portion of the template with clear orthodontic resin. Place the template onto the cast and allow the material to set (figure 3) working the template on and off the cast as it sets to prevent it from locking onto the cast.

 

             

                                          Figure 3

 

            6. Upon collaboration with the surgeon, place a hole in the desired position of the implant template taking into account the adjacent teeth and anatomic structures and contours of the desired restoration. (Figure 4) Do not compromise the implant position due to lack of bone.

 

             

                                          Figure 4

 

 There are many predictable grafting techniques to improve ridge width and height. You may want to reduce the clinical height of the template or create an access groove to make it easier for the surgeon to place the guide drill into the template. (Figure 5)

 

          

                                                                              Figure 5

 

This technique does not take into account the exact position of the underlying bone and anatomic structures. It approximates the desired implant position but visualization of the ridge anatomy and underlying structures must be performed by the surgeon during placement. There are computer based CT generated planning software programs that take into account the desired restoration along with the CT image of bone and anatomic structures and allows for precision placement of the dental implant with a very precisely fabricated surgical template.

 

Hope this helps!!