Intraoral Digital Impression Technique Compared to Conventional Impression Technique. A Randomized Clinical Trial Bj ¨ orn Gjelvold, DDS, 1 Bruno Ramos Chrcanovic, DDS, MSc, 2 Eva-Karin Korduner, DDS, 1 Ingrid Collin-Bagewitz, DDS, PhD, 1 & Jen ¨ o Kisch, DDS 1 1 Folktandv ˚ arden Sk ˚ ane AB—Centre of Dental Specialist Care Malm ¨ o, Malm ¨ o, Sweden 2 Department of Prosthodontics, Malm ¨ o University, Malm ¨ o, Sweden Keywords Digital impression; computer-aided impression; clinical efficiency; intraoral scanner; patient perception; CAD/CAM. Correspondence Bj ¨ orn Gjelvold, Folktandv ˚ arden Sk ˚ ane AB—Centre of Dental Specialist Care Malm ¨ o, Sp˚ arv ¨ agsgatan 12 Malm ¨ o 214 27, Sweden. E-mail: bjorn.gjelvold@gmail.com. Bruno Ramos Chrcanovic ORCID: http://orcid.org/0000-0002-3460-3374 Bj ¨ orn Gjelvold ORCID: http://orcid.org/0000-0001-6186-4804 Funded by Region Sk ˚ ane and Folktandv ˚ arden Sk˚ ane AB (Public Dental Care Service, Scania, Sweden). The authors deny any conflicts of interest. Accepted July 24, 2014 doi: 10.1111/jopr.12410 Abstract Purpose: To compare digital and conventional impression techniques in a randomized clinical trial; specifically, procedure times, patient-centered outcomes, and clinical evaluation of the restorations. Materials and Methods: Forty-two patients in need of tooth-supported single crowns and/or fixed partial prostheses up to six units were randomly allocated to one of the impression techniques. The procedure times, dentists’ and patients’ assessments using a visual analog scale (VAS), and clinical evaluation of the restorations were compared between the two groups. Results: The mean total procedure times for digital and conventional impression technique were 14:33 ± 5:27 and 20:42 ± 5:42, respectively (p < 0.0001). Mean impression times were 7:33 ± 3.37 and 11:33 ± 1.56, respectively (p < 0.0001). Mean VAS scores for the dentist’s assessment of difficulty (0 to 100; very difficult = 100) were 24.00 ± 18.02 and 48.02 ± 21.21, respectively (p < 0.0001). Mean VAS scores for the patients’ assessment of discomfort (0 to 100; very discomforting = 100) was 6.50 ± 5.87 and 44.86 ± 27.13, respectively (p < 0.0001). Occlusal contacts showed a better result for the digital technique. Conclusion: The results of this study demonstrated that the digital technique was more efficient and convenient than the conventional impression technique. Dental impressions have been used to obtain impressions of the intraoral conditions; casts need to be made to fabricate restorations on the casts. Impressions have a wide range of applications, ranging from providing casts for treatment plan- ning or patient communication to providing final casts for the production of definitive/interim restorations. 1 In the so-called “conventional” technique, a cast is produced after an impression has been made with a tray filled with an impression material. Impressions made with irreversible hy- drocolloids should be poured immediately, as delayed pouring negatively influences their dimensional stability and precision. 2 Elastomeric impression materials available for final impres- sions are vinyl siloxanether, vinylpolysiloxane, silicone, and polyether. 3 They are still the most common methods of transferring information from the patient to the dental labo- ratory when making indirect restorations. 1 With the increasing use of digital intraoral impression sys- tems, developed in the 1980s, the total elimination of phys- ical casts using conventional impression systems has become possible. 4 In the digital system, the intraoral condition has been digitally recorded using an intraoral 3D acquisition device, and the acquired information enables the computer to generate a vir- tual model. Definitive restorations are fabricated on the basis of the virtual model. 5 An increasing number of fixed prosthe- ses have been manufactured with intraoral digital impression techniques now becoming an important part of the digitization process of prosthodontics. 6 The digital impression technique has many advantages, such as improvement of patient acceptance, reduction in the distortion of impression materials, the possibility of providing improved 3D previsualization of tooth preparations, and potential cost- and time-effectiveness. 4,7-11 Previous 1 Journal of Prosthodontics 00 (2015) 1–6 C  2015 by the American College of Prosthodontists