Comparison of digital scanning and conventional impression taking for implant-supported prostheses

The effect of discrepancies between digital scans and conventional impressions on the clinical performance of a permanent restoration has not been fully understood.Thirty patients received conventional impressions and digital scans of a single implant restoration. Two crowns were made for the same implant using both methods. The time taken for each procedure was recorded. After analyzing the accuracy and effectiveness of both crowns, the best one was placed. A questionnaire was conducted to assess the preferences and comfort when using crowns made by one method or another.The total time for the traditional impression technique was 15 minutes, while the time for the digital scanning technique was significantly less – 10 minutes.The preparation time, including the disinfection of the silicone impressions, their transportation to the laboratory, the casting of the impressions, the hardening of the plaster, as well as the preparation of the model by the technician, was 4 hours for conventional impressions.The timing for sending the STL file and modeling the structure was less than 2 hours for the digital scan method. The production time of crowns takes 3 hours for both conventional impressions and digital ones.Of all crowns selected for placement, 46.7% were made from conventional impressions and 53.3% from digital scans. Participants preferred the digital scanning technique (89%) over the traditional impression-taking technique (11%).The data from this study suggest that digital scanning and CAD/CAM technology may be more effective and better accepted by study par-ticipants for a single implant restoration than conventional impressions and plaster casts.

Digital mapping of a manual fabrication method for paediatric ankle–foot orthoses

Ankle–foot orthoses (AFOs) are devices prescribed to improve mobility in people with neuromuscular disorders. Traditionally, AFOs are manually fabricated by an orthotist based on a plaster impression of the lower leg which is modified to correct for impairments. This study aimed to digitally analyse this manual modification process, an important first step in understanding the craftsmanship of AFO fabrication to inform the digital workflows (i.e. 3D scanning and 3D printing), as viable alternatives for AFO fabrication. Pre- and post-modified lower limb plaster casts of 50 children aged 1–18 years from a single orthotist were 3D scanned and registered. The Euclidean distance between the pre- and post-modified plaster casts was calculated, and relationships with participant characteristics (age, height, AFO type, and diagnosis) were analysed. Modification maps demonstrated that participant-specific modifications were combined with universally applied modifications on the cast's anterior and plantar surfaces. Positive differences (additions) ranged 2.12–3.81 mm, negative differences (subtractions) ranged 0.76–3.60 mm, with mean differences ranging from 1.37 to 3.12 mm. Height had a medium effect on plaster additions (rs = 0.35). We quantified the manual plaster modification process and demonstrated a reliable method to map and compare pre- and post-modified casts used to fabricate children's AFOs.

VERGILIUS

Vincenzo Capozzoli presents VERGILIUS, a collaborative platform for studying and promoting the heritage of the University of Paris 1 Panthéon-Sorbonne, which consists in Greek antiquities, a model of the ancient city of Rome, a collection of pottery sherds from the Near East, a corpus of stamp seals from ancient Iran, several thousands of slides and photographs, the archives of former professors, a collection of plaster casts and a film library. Since October 2011, these collections have been digitized and organised into archives and virtual exhibitions. This work has proved a valuable training instrument for students, who learn about the objects and their history but also significantly improve their IT skills.