Biocompatibility of posterior restorative materials

Biocompatibility of dental materials is an important consideration for the patient, clinician, laboratory technician and manufacturer. This paper examines biocompatibility testing methods and the biocompatibility of posterior restorative materials, including amalgam, casting alloys, resin composites, dentin bonding agents, cements, porcelains and ceramics.     

Age-related changes in the electrophysiological response to visual stimulus novelty: a topographical approach

The relationship of task relevance and stimulus probability to P300 morphology, latency and distribution was assessed. Eight year olds and adults completed visual oddball tasks of recognition memory with frequent non-target (60%), infrequent target (20%), and infrequent novel (20%) stimuli. Stimuli consisted of 2 female faces posing neutral expressions, and 40 trial unique novel photographs depicting scenes, animals, objects or abstract patterns. Event-related potentials were recorded from 17 electrodes over frontal, central and parietal scalp, including lateral temporal sites. All stimuli elicited P300 responses at parietal electrodes, with the largest responses to the target stimuli (relevant and infrequent). The P300 responses of adults and children were morphologically dissimilar, with children showing broader peaks and latency shifts across electrodes. In addition, the eight year olds displayed a frontal negativity to novel stimuli which was absent in the responses of adult participants. Results suggest that different anatomical or functional circuitry may be involved in the processing of novelty for adults as compared to eight year olds.     

Normal brain F-18 FDG-PET and MRI anatomy

Image registration techniques will become increasingly important in correlative multimodality imaging. In the case of PET, a structural imaging study can be invaluable in correlating structure metabolism relationships. A registered brain atlas of PET and MRI has been developed by the authors that allows clinicians, residents, fellows, and others to refer to a structural abnormality on MRI or metabolic abnormality on PET and correlate it neuro-anatomically.     

Prehospital resuscitation of hypotensive trauma patients with 7.5% NaCl versus 7.5% NaCl with added dextran: a controlled trial

Small volume infusions of hypertonic saline combined with dextran are very effective in resuscitating animals that have been subjected to hemorrhagic shock, and seem to be effective in resuscitating trauma patients with severe injuries. In this study, the contribution of the dextran component was investigated in a prospective, three-armed, double-blind, randomized trial. Trauma patients transported by ambulance to the hospital with a systolic blood pressure of 90 mm Hg or less were given 250 mL of (1) normal saline (NS); (2) 7.5% NaCl (HS, for hypertonic saline); or (3) 7.5% NaCl in 6% dextran 70 (HSD). Infusion of the study solution was followed by administration of conventional isotonic fluids as the patients' conditions indicated. By predetermined hypothesis, the observed survival rates in the three treatment groups were compared with the predicted survival rates from the TRISS methodology. The 7.5% NaCl solution significantly improved upon the predicted survival for the entire cohort and for high-risk patients when compared with the survival estimates from the TRISS methodology. The addition of a colloid, in the form of 6% dextran 70, did not offer any additional benefit, at least in this setting of rapid urban transport.