Comparison of oral surgery task performance in a virtual reality surgical simulator and an animal model using objective measures.

The use of virtual reality (VR) simulation for surgical training has gathered much interest in recent years. Despite increasing popularity and usage, limited work has been carried out in the use of automated objective measures to quantify the extent to which performance in a simulator resembles performance in the operating theatre, and the effects of simulator training on real world performance. To this end, we present a study exploring the effects of VR training on the performance of dentistry students learning a novel oral surgery task. We compare the performance of trainees in a VR simulator and in a physical setting involving ovine jaws, using a range of automated metrics derived by motion analysis. Our results suggest that simulator training improved the motion economy of trainees without adverse effects on task outcome. Comparison of surgical technique on the simulator with the ovine setting indicates that simulator technique is similar, but not identical to real world technique.

Local regularization of tilt projections reduces artifacts in electron tomography.

Electron tomography produces very high resolution 3D image volumes useful for investigating the structure and function of cellular components. Unfortunately, unavoidable discontinuities and physical constraints in the acquisition geometry lead to a range of artifacts that can affect the reconstructed image. In particular, highly electron dense regions, such as gold nanoparticles, can hide proximal biological structures and degrade the overall quality of the reconstructed tomograms. In this work we introduce a pre-reconstruction non-conservative non-linear isotropic diffusion (NID) filter that automatically identifies and reduces local irregularities in the tilt projections. We illustrate the improvement in quality obtained using this approach for reconstructed tomograms generated from samples of malaria parasite-infected red blood cells. A quantitative and qualitative evaluation for our approach on both simulated and real data is provided.

Improving the quality of electron tomography image volumes using pre-reconstruction filtering.

Electron tomography produces highly magnified 3D image volumes useful for investigating the structure and function of cellular components. Image quality is degraded by multiple scattering events and quantum noise, which depend on the angle at which individual tilt projections are collected. We have adapted a biomedical imaging approach to improve image quality by enhancing individual tilt projections prior to volumetric reconstruction. Specifically, we have developed a family of non-linear anisotropic diffusion (NAD) filters parameterized by the tilt angle. We give a quantitative and qualitative evaluation of our pre-processing approach and the NAD filter. We show an improvement in the reconstructed volumes for tomograms generated from both plastic-embedded and cryo-stabilized samples of malaria parasite-infected erythrocytes.

Towards defining dental drilling competence, part 1: a study of bone drilling technique.

Technical skills are critical for dentists. Computer-based simulation offers a range of potential benefits for surgical training, but to date the development of simulators has not been characterized by a structured investigation of specific mechanisms by which trainees attain competence. This two-part study contributes to the understanding of the manner in which surgical psychomotor skills are acquired so that this knowledge can be incorporated into the design of training simulations. We studied participant groups of varying skill levels as they performed a drilling task in oral surgery. In this first part of our study, we investigated the elements of surgical technique and differences in the drilling performance of novice, competent, and expert dentists. Our results indicate that novice dentists employ a technique that differs considerably in drilling stroke length and duration from that employed by experts. Expert dentists perform faster, apply more force, lift the bur off the bone less, and produce superior results compared with novices.

Towards defining dental drilling competence, part 2: a study of cues and factors in bone drilling.

The study of expertise in surgery aims to facilitate the development of improved training methods by understanding the characteristics of expert practitioners. In this article and its companion, we present our study of the characteristics of competence and expertise in the field of oral surgery. We observed participants of different skill levels as they performed an ex vivo drilling task designed to test the psychomotor skill of distinguishing the material boundaries between tooth and bone. Part 1 of this study examined the physical characteristics of drilling performance, while this article examines the cognitive aspects of performance. In this article we investigate the psychomotor cues used for decision making during drilling and explore other factors that affect a participant's ability to distinguish tooth from bone. Our results suggest that visual and tactile cues were the most important cues guiding drilling performance in all participant groups. Our results also suggest that when compared to experts, novices relied more on visual cues rather than tactile cues and lacked the psychomotor skills required to utilize the broader range of cues used by experts.