James F. Fondriest, DDS and David C. McClenahan, DDS
This article provides a step-by-step procedure for producing radiographic stents. Two common treatment scenarios are explored.
Computed tomography (CT) studies can be used to determine the suitability, appropriate sites and the size of the implant to be placed. They also provide information on the need for pre-implantation ridge surgery.
These studies can be enhanced with the use of radiographic markers that can show the location and tooth contours of the proposed restoration,1-2 as well as the use of interactive software (SIM-Plant, Columbia Scientific). S1MPlant allows the implant team to analyze CT data on their personal computers. This software allows the manipulation of the three-dimensional data to provide maximum information on the anatomic structures, bone quality and quantity, and it can be used ,to measure accurately in any dimension.3
By using radiographic markers at the time of scanning, the surgeon and restorative dentist can plan the exact placement of implants with respect to embrasures, cemento-enamel junction of adjacent teeth and emergence profiles relative to the planned contour of the anticipated prosthetic restoration.4
Radiographic preplanning also allows the restorative dentist to anticipate the prosthetic parts necessary to complete the treatment plan. A more predictable time and cost estimate can therefore be made for the patient. This cumulative knowledge helps to further implant restoration predictability.
This article features a method of fabricating radiographic treatment planning stents for use in cross-sectional radiography (linear tomography or CT scans). Each method is broken down into steps for convenient reference.
Case 1: Posterior edentulous mandible
1.Duplicate and mount study casts (Fig 1).
2.Wax up preliminary treatment plan and duplicate in stone or develop a composite (Triad, Dentsply) model 5 (Fig 2).
3.Make a suckdown template of 1 mm clear shim (Biocryl, Great Lakes Orthodontics) using a clear acrylic sheet (Biostark, Great Lakes Orthodontics) over the hard model (Fig. 3).
4.Trim excess plastic to allow for ease of placement and removal from the duplicate hard model (Fig. 4).
5.Mix barium sulfate USP (white powder that can be procured from radiology clinic at hospital or from local pharmacist) with acrylic powder (Jet, Lang Dental Manufacturing) in a ratio of one part barium sulfate, 10 parts powder (Fig. 5).
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