Evaluation of Intraoral Scanning Technique in Fabrication of Implant Supported Full Arch Fixed Screw Retained Superstructure.

Thesis Type: Dental Specialty

Institution Of The Thesis: Hacettepe University, Diş Hekimliği Fakültesi, Diş Hekimliği Klinik Bilimler Bölümü, Turkey

Approval Date: 2017

Thesis Language: Turkish


Supervisor: Kıvanç Akça


In recent years, direct digital impression (direct-dI) technique has been evolved into implant supported fixed partial dentures. However, knowledge with regards to use of the same technology for edentulous arches is insufficient. The aim of this study, therefore, was to compare positional accuracy of implants recorded with conventional impression (cI) and direct-dI techniques. For this purpose, four implants, two straight anterior and two angulated posterior, supporting fixed full-arch screw retained prosthesis in rehabilitation of maxillary edentulism was studied. In simulation of the described  clinical scenario, a solid master model was used in impression making of dental implants with conventional and digital techniques. For cI group, implants were recorded with open- and closed-tray approach using elastomeric impression material, and followed by study cast model production with dental stone. For direct-dI group, different scan-posts, original and non-original approach, were digitalized using an intraoral scanner. From these data study digital models were designed, and 3D printed with additive manufacturing. Implant positions in  all study cast- and digital- models were recorded manually and visually in three dimension using co-coordinate measuring machine (CMM) and laser scanning machine (LSM) respectively. Implant positions were compared between impression techniques and within each impression approach as well.  Except for posterior angulated implants recorded with cI and direct-DI, differences for all implant positions in angular measurements with CMM between impression techniques and within impression approach were statistically insignificant. All implant positions in linear measurements displayed statistically insignificant difference. LSM implant angulation data were statistically different for anterior straight implants between cI and direct-DI techniques, and within direct-dI technique for original versus non-original scan posts aproch. All other measurements presented insignificant differences both between impression techniques and within impressioın approaches. direct-dI technique using an intraoral scanner in fabrication of full-arch implant supported fixed restoration is promising due to similar implant position recordings compared to cI technique. Furthermore, use of non-original scan posts may be considered as an alternate to originals. In conclusion direct-dI technique can be accepted as a valid concept in recording of implant positions with different angulations to support full arch one-piece screw retained implant superstructures.