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.

Effect of hypoxia on TRPV1 and TRPV4 channels in rat pulmonary arterial smooth muscle cells.

Transient receptor potential (TRP) channels of the vanilloid subfamily, mainly TRPV1 and TRPV4, are expressed in pulmonary artery smooth muscle cells (PASMC) and implicated in the remodeling of pulmonary artery, a landmark of pulmonary hypertension (PH). Among a variety of PH subtypes, PH of group 3 are mostly related to a prolonged hypoxia exposure occurring in a variety of chronic lung diseases. In the present study, we thus investigated the role of hypoxia on TRPV1 and TRPV4 channels independently of the increased pulmonary arterial pressure that occurs during PH. We isolated PASMC from normoxic rat and cultured these cells under in vitro hypoxia. Using microspectrofluorimetry and the patch-clamp technique, we showed that hypoxia (1 % O2 for 48 h) significantly increased stretch- and TRPV4-induced calcium responses. qRT-PCR, Western blotting, and immunostaining experiments revealed that the expression of TRPV1 and TRPV4 was not enhanced under hypoxic conditions, but we observed a membrane translocation of TRPV1. Furthermore, hypoxia induced a reorganization of the F-actin cytoskeleton, the tubulin, and intermediate filament networks (immunostaining experiments), associated with an enhanced TRPV1- and TRPV4-induced migratory response (wound-healing assay). Finally, as assessed by immunostaining, exposure to in vitro hypoxia elicited a significant increase in NFATc4 nuclear localization. Cyclosporin A and BAPTA-AM inhibited NFATc4 translocation, indicating the activation of the Ca(2+)/calcineurin/NFAT pathway. In conclusion, these data point out the effect of hypoxia on TRPV1 and TRPV4 channels in rat PASMC, suggesting that these channels can act as direct signal transducers in the pathophysiology of PH.