The aim of this study was to evaluate the accuracy of full-arch digital impressions when compared to conventional impressions, when performed on the abutment or implant level. Methods: One resin cast with six implants and another cast with six abutments were scanned with Primescan v5.1 (PS51), Primescan v5.2 (PS52), Trios 3 (T3), and Trios 4 (T4). Additionally, conventional impressions (A) were made, poured in gypsum, and digitized using a lab scanner (IScan D104i). A coordinate machine (Atos, GOM, Braunschweig, Germany) was used to generate the reference scan of both casts. For all scans, the position of the implants was calculated and matched with the reference scan. Angular and coronal measurements per implant were considered for trueness and precision. Results: For the implant-level model, PS52 performed significantly better in terms of trueness and precision compared to all other impressions, except for the angular trueness of A (p = 0.072) and the coronal trueness of PS51 (p = 1.000). For the abutment-level model, PS52 also performed significantly better than all other impressions, except for the coronal trueness and precision of A (p = 1.000). Conclusions: Digital impressions for full-arch implant supported prostheses can be as accurate as conventional impressions, depending on the intra-oral scanner and software. Overall, abutment level impressions were more accurate compared to implant level impressions.

Objective: It has been stated that blood pigments within discolored teeth may interfere with Laser Doppler Flowmetry (LDF) measurements. The aim of this study was to assess pulp vitality with LDF in a cohort of discolored traumatized teeth referred for endodontic treatment or where the referring dentist had doubts regarding maintained tooth vitality. Background: Discoloration of teeth is a common sequel of dental trauma. Still today, it is taken as an indicator for root canal treatment. Transient apical breakdown (TAB) is confused with apical periodontitis, although it is a sequel of dental trauma in young mature teeth and will result in revascularization and dissolution of the apical radiolucency. Methods: A total of 26 patients with 28 discolored teeth, belonging to a cohort of referred patients with traumatized teeth referred for root canal treatment and/or pulp vitality assessment were screened on color with photographs by three investigators, with traditional sensibility tests and with a Moor VMS II LDF meter. Results: The color of the intrinsically discolored teeth was grayish in 58% of teeth, blue 20%, pink/crimson 12%, and yellow 4%. Eighty-five percent were central maxillary incisors, 11% were mandibulary incisors. Thanks to LDF, 43% of the trauma cases in this small cohort with discoloration underwent root canal treatment instead of 70% with traditional sensibility tests as indicator. TAB was found in 11%. Conclusions: LDF was decisive in diagnosing vitality of discolored teeth and there was no negative impact of tooth discoloration on LDF measurements.