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.

Control of vertebrate skeletal mineralization by polyphosphates.

BACKGROUND: Skeletons are formed in a wide variety of shapes, sizes, and compositions of organic and mineral components. Many invertebrate skeletons are constructed from carbonate or silicate minerals, whereas vertebrate skeletons are instead composed of a calcium phosphate mineral known as apatite. No one yet knows why the dynamic vertebrate skeleton, which is continually rebuilt, repaired, and resorbed during growth and normal remodeling, is composed of apatite. Nor is the control of bone and calcifying cartilage mineralization well understood, though it is thought to be associated with phosphate-cleaving proteins. Researchers have assumed that skeletal mineralization is also associated with non-crystalline, calcium- and phosphate-containing electron-dense granules that have been detected in vertebrate skeletal tissue prepared under non-aqueous conditions. Again, however, the role of these granules remains poorly understood. Here, we review bone and growth plate mineralization before showing that polymers of phosphate ions (polyphosphates: (PO(3)(-))(n)) are co-located with mineralizing cartilage and resorbing bone. We propose that the electron-dense granules contain polyphosphates, and explain how these polyphosphates may play an important role in apatite biomineralization. PRINCIPAL FINDINGS/METHODOLOGY: The enzymatic formation (condensation) and destruction (hydrolytic degradation) of polyphosphates offers a simple mechanism for enzymatic control of phosphate accumulation and the relative saturation of apatite. Under circumstances in which apatite mineral formation is undesirable, such as within cartilage tissue or during bone resorption, the production of polyphosphates reduces the free orthophosphate (PO(4)(3-)) concentration while permitting the accumulation of a high total PO(4)(3-) concentration. Sequestering calcium into amorphous calcium polyphosphate complexes can reduce the concentration of free calcium. The resulting reduction of both free PO(4)(3-) and free calcium lowers the relative apatite saturation, preventing formation of apatite crystals. Identified in situ within resorbing bone and mineralizing cartilage by the fluorescent reporter DAPI (4',6-diamidino-2-phenylindole), polyphosphate formation prevents apatite crystal precipitation while accumulating high local concentrations of total calcium and phosphate. When mineralization is required, tissue non-specific alkaline phosphatase, an enzyme associated with skeletal and cartilage mineralization, cleaves orthophosphates from polyphosphates. The hydrolytic degradation of polyphosphates in the calcium-polyphosphate complex increases orthophosphate and calcium concentrations and thereby favors apatite mineral formation. The correlation of alkaline phosphatase with this process may be explained by the destruction of polyphosphates in calcifying cartilage and areas of bone formation. CONCLUSIONS/SIGNIFICANCE: We hypothesize that polyphosphate formation and hydrolytic degradation constitute a simple mechanism for phosphate accumulation and enzymatic control of biological apatite saturation. This enzymatic control of calcified tissue mineralization may have permitted the development of a phosphate-based, mineralized endoskeleton that can be continually remodeled.

Simulation-based medical error disclosure training for pediatric healthcare professionals.

Ethical and regulatory guidelines recommend disclosure of medical errors to patients and families. Yet few studies examine how to effectively train healthcare professionals to deliver communications about adverse events to family members of affected pediatric patients. This pilot study uses a preintervention-postintervention study design to investigate the effects of medical error disclosure training in a simulated setting for pediatric oncology nurses (N=16). The results of a paired t test showed statistically significant increases in nurses' communication self-efficacy to carry out medical disclosure (t = 6.68, p < .001). Ratings of setting "realism" and simulation effectiveness were high (21 out of 25 composite score). Findings provide preliminary support for further research on simulation-based disclosure training for healthcare professionals.

Absence of the proapoptotic Bax protein extends fertility and alleviates age-related health complications in female mice.

The menopausal transition in human females, which is driven by a loss of cyclic ovarian function, occurs around age 50 and is thought to underlie the emergence of an array of health problems in aging women. Although mice do not undergo a true menopause, female mice exhibit ovarian failure long before death because of chronological age and subsequently develop many of the same age-associated health complications observed in postmenopausal women. Here we show in mice that inactivation of the proapoptotic Bax gene, which sustains ovarian lifespan into advanced age, extends fertile potential and minimizes many age-related health problems, including bone and muscle loss, excess fat deposition, alopecia, cataracts, deafness, increased anxiety, and selective attention deficit. Further, ovariectomy studies show that the health benefits gained by aged females from Bax deficiency reflect a complex interplay between ovary-dependent and -independent pathways. Importantly, and contrary to popular belief, prolongation of ovarian function into advanced age by Bax deficiency did not lead to an increase in tumor incidence. Thus, the development of methods for postponing ovarian failure at menopause may represent an attractive option for improving the quality of life in aging females.