Dental student self-assessment of a medical history competency developed by Oral and Maxillofacial Surgery Faculty.

PURPOSE: To develop a standardized competency exam to evaluate dental student knowledge of patients with complex medical histories. Analysis was performed to determine if there is a difference between dental student self-assessment of the exam compared to oral surgery faculty. The overall goal is to enhance student comprehension of advanced medical patients in the pre-doctoral oral and maxillofacial surgery clinic and make changes based on student responses. METHODS: The exam took place in a simulation laboratory containing two-way mirrors where the student could not see the evaluator. Three standardized patients (trained actors) were given different medical history scenarios to learn prior to the exam. Students were randomly assigned to interview one patient. The graders consisted of senior and junior level faculty. In real time (live) randomized manner, faculty assessed each student using a standardized rubric to assign a score of 1 to 4. Immediately afterwards, students assessed their own performance using the same scale. RESULTS: Students gave themselves significantly higher grades (P < 0.001) on the exam (10.7 ± 0.12) compared to the faculty (9.2 ± 0.17). There was no significant difference in student (P = 0.16) or faculty assessment (P = 0.29) between the three different medical scenarios. There was no significant difference between faculty in assessment of student performances (P = 0.16). CONCLUSION: These results suggested that students overestimated their performance compared to the faculty assessment. This could be due to that students assessed their performance based on memory and self-confidence; that exceeds their expectations. Internal calibration of student performances and faculty grading using standardized criteria may produce more accurate and reliable outcomes in student scoring.

Methamphetamine abuse and dentistry.

Methamphetamine is a highly addictive powerful stimulant that increases wakefulness and physical activity and produces other effects including cardiac dysrhythmias, hypertension, hallucinations, and violent behavior. The prevalence of methamphetamine use is estimated at 35 million people worldwide and 10.4 million people in the United States. In the United States, the prevalence of methamphetamine use is beginning to decline but methamphetamine trafficking and use are still significant problems. Dental patients who abuse methamphetamine can present with poor oral hygiene, xerostomia, rampant caries ('Meth mouth'), and excessive tooth wear. Dental management of methamphetamine users requires obtaining a thorough medical history and performing a careful oral examination. The most important factor in treating the oral effects of methamphetamine is for the patient to stop using the drug. Continued abuse will make it difficult to increase salivary flow and hinder the patient's ability to improve nutrition and oral hygiene. Local anesthetics with vasoconstrictors should be used with care in patients taking methamphetamine because they may result in cardiac dysrhythmias, myocardial infarction, and cerebrovascular accidents. Thus, dental management of patients who use methamphetamine can be challenging. Dentists need to be aware of the clinical presentation and medical risks presented by these patients.

High resolution protein localization using soft X-ray microscopy.

Soft X-ray microscopes can be used to examine whole, hydrated cells up to 10 microm thick and produce images approaching 30 nm resolution. Since cells are imaged in the X-ray transmissive "water window", where organic material absorbs approximately an order of magnitude more strongly than water, chemical contrast enhancement agents are not required to view the distribution of cellular structures. Although living specimens cannot be examined, cells can be rapidly frozen at a precise moment in time and examined in a cryostage, revealing information that most closely approximates that in live cells. In this study, we used a transmission X-ray microscope at photon energies just below the oxygen edge (lambda = 2.4 nm) to examine rapidly frozen mouse 3T3 cells and obtained excellent cellular morphology at better than 50 nm lateral resolution. These specimens are extremely stable, enabling multiple exposures with virtually no detectable damage to cell structures. We also show that silver-enhanced, immunogold labelling can be used to localize both cytoplasmic and nuclear proteins in whole, hydrated mammary epithelial cells at better than 50 nm resolution. The future use of X-ray tomography, along with improved zone plate lenses, will enable collection of better resolution (approaching 30 nm), three-dimensional information on the distribution of proteins in cells.

The role of pH and osmolarity in evoking the acetic acid-induced wiping response in a model of nociception in frogs.

Acetic acid applied to the hindlimb of a frog evokes a vigorous wiping of the exposed skin. The aim of this study was to determine if acetic acid evokes this wiping response by decreasing subepidermal pH. Because acetic acid is hyperosmolar, a second aim was to determine if the osmolarity of acetic acid contributed to evoking the wiping response. In behavioral experiments, different acids or acetic acid/sodium acetate buffers at different pHs were used to evoke the wiping response. In separate experiments, subepidermal pH was measured in vitro while these same solutions were applied to samples of skin from frogs. The wiping response evoked by acetic acid was associated with a decrease in subepidermal pH to a level that has been shown to activate nociceptors. Interestingly, formic, oxalic, sulfuric, and hydrochloric acid evoked the wiping response without decreasing subepidermal pH. The osmolarity of acetic acid contributed to evoking the wiping response because buffers at subthreshold pHs evoked the wiping response. Also, the osmolarity required to evoke the wiping response depended upon the pH of the buffer. Thus, acetic acid and the buffers at pH 2.97 and 4.67 could evoke the wiping response by decreasing subepidermal pH. In contrast, formic, oxalic, sulfuric, and hydrochloric acid, as well as the buffers at pH 5.17 and 5.67, evoked the wiping response through another mechanism, perhaps by increasing subepidermal osmolarity. These studies demonstrate that both pH and osmolarity may contribute to nociception produced by algesic chemicals and may be important in inflammatory pain.

Intraplantar injection of hyaluronic acid at low pH into the rat hindpaw produces tissue acidosis and enhances withdrawal responses to mechanical stimuli.

Application of buffers covering a range of acidic pH values activates and sensitizes nociceptors and produces pain. The purpose of this study was to determine whether a range of acidic pH in tissue produces mechanical hyperalgesia. Tissue acidosis was produced in the hindpaw of the rat by intraplantar injections of hyaluronic acid (HA) adjusted to pH 7.4, 6.0, 5.0, 4.0 or 3.0. Mechanical hyperalgesia was assessed by evaluating responses to application of a von Frey monofilament to the plantar surface before and after injection of HA. In separate experiments, magnitude of tissue acidosis produced by injection of HA was determined by measuring pH of intraplantar tissue using a pH microelectrode. Although needle stick alone produced mechanical hyperalgesia, intraplantar injections of HA at pH 6.0 or 5.0 produced significantly greater mechanical hyperalgesia. In contrast, mechanical hyperalgesia produced by injection of HA at pH 7.4, 4.0 or 3.0 was not different from that produced by needle stick. Although injection of HA at low pH produced tissue acidosis in a pH dependent manner, only a narrow range of tissue acidosis (pH = 6.38-6.00) produced mechanical hyperalgesia. Our data suggest that tissue acidosis induces mechanical hyperalgesia; however, the range of tissue pH that produces this effect is limited.