In vitroandin vivocharacterization of a novel tricalcium silicate-based ink for bone regeneration using laser-assisted bioprinting.

Grafts aside, current strategies employed to overcome bone loss still fail to reproduce native tissue physiology. Among the emerging bioprinting strategies, laser-assisted bioprinting (LAB) offers very high resolution, allowing designing micrometric patterns in a contactless manner, providing a reproducible tool to test ink formulation. To this date, no LAB associated ink succeeded to provide a reproduciblead integrumbone regeneration on a murine calvaria critical size defect model. Using the Conformité Européenne (CE) approved BioRoot RCS® as a mineral addition to a collagen-enriched ink compatible with LAB, the present study describes the process of the development of a solidifying tricalcium silicate-based ink as a new bone repair promoting substrates in a LAB model. This ink formulation was mechanically characterized by rheology to adjust it for LAB. Printed aside stromal cells from apical papilla (SCAPs), this ink demonstrated a great cytocompatibility, with significantin vitropositive impact upon cell motility, and an early osteogenic differentiation response in the absence of another stimulus. Results indicated that thein vivoapplication of this new ink formulation to regenerate critical size bone defect tends to promote the formation of bone volume fraction without affecting the vascularization of the neo-formed tissue. The use of LAB techniques with this ink failed to demonstrate a complete bone repair, whether SCAPs were printed or not of at its direct proximity. The relevance of the properties of this specific ink formulation would therefore rely on the quantity appliedin situas a defect filler rather than its cell modulation properties observedin vitro. For the first time, a tricalcium silicate-based printed ink, based on rheological analysis, was characterizedin vitroandin vivo, giving valuable information to reach complete bone regeneration through formulation updates. This LAB-based process could be generalized to normalize the characterization of candidate ink for bone regeneration.

Influence of practical and clinical experience on dexterity performance measured using haptic virtual reality simulator.

INTRODUCTION: Development of dexterity, hand-eye coordination and self-assessment are essential during the preclinical training of dental students. To meet this requirement, dental simulators have been developed combining virtual reality with a force feedback haptic interface. The aim of this study was to assess the capability of the VirTeaSy© haptic simulator to discriminate between users with different levels of practical and clinical experience. MATERIALS AND METHODS: Fifty-six volunteers divided into five groups (non-dentists, 1st/3rd/final-year dental students, recent graduates) had three attempts to prepare an occlusal amalgam cavity using the simulator. Percentages of volumes prepared inside (%IV) and outside (%OV) the required cavity, skill index and progression rate, referring to the evolution of skill index between trials 1 and 3, were assessed. The dental students and recent graduates completed a questionnaire to gather their opinions about their first hands-on experience with a haptic simulator. RESULTS: The results showed no significant difference between the groups at the first attempt. Following the third attempt, the skill index was improved significantly. Analysis of progression rates, characterised by large standard deviations, did not reveal significant differences between groups. The third attempt showed significant differences in skill index and %IV between 1st-year undergraduate dental students and both non-dentists and recent dental graduates. The questionnaire indicated a tendency for dental operators to consider the simulator as a complement to their learning and not a substitute for traditional methods. CONCLUSION: This study did not show the ability of a basic aptitude test on VirTeaSy© haptic simulator to discriminate between users of different levels of expertise. Optimisations must be considered in order to make simulation-based assessment clinically relevant.