Photogrammetry - An alternative to conventional impressions in implant dentistry? A clinical pilot study

Purpose: The purpose of this clinical pilot study was to describe a photogr ammetric technique to determine implant positions in the oral cavity, and t o test and compare this technique to conventional impression/master cast pr ocedures for fabrication of titanium frameworks with a computer numeric-con trolled (CNC) milling technique. Materials and Methods: Implant positions w ere recorded by means of conventional impressions/master casts as well as i ntraoral 3-dimensional photogrammetric measurements in 2 patients who were provided with 5 Branemark implants each in the edentulous mandible, For eac h patient 2 titanium frameworks were made by means of a CNC milling techniq ue (All-in-One). Both frameworks had an identical design, but the orientati ons of the framework cylinder fit surfaces were machined either from measur ements from the master casts or from the intraoral photogrammetric measurem ents. The frameworks were tried for fit in the oral cavity and on the maste r casts. Results: Both cases showed different precision of fit when compari ng the 2 frameworks on the master casts. One of the 2 photogrammetric frame works was not considered acceptable when tried on the models. In the oral c avity, however, all 4 frameworks presented comparable fit, and all were acc epted for clinical use. Conclusion: The clinical experiences with try-in of the 4 different frameworks indicated that the photogrammetric technique co uld be a valid option for conventional impressions when using CNC milling f abrication in implant dentistry. The different results from the model and o ral examinations also imply the difficulties of assessing clinical fit when testing fit at the master cast level only.