Integration of Laser Scanning and Three-dimensional Models in the Legal Process Following an Industrial Accident.

BACKGROUND: In order to obtain a deeper understanding of an incident, it needs to be investigated to "peel back the layers" and examine both immediate and underlying failures that contributed to the event itself. One of the key elements of an effective accident investigation is recording the scene for future reference. In recent years, however, there have been major advances in survey technology, which have provided the ability to capture scenes in three dimension to an unprecedented level of detail, using laser scanners. METHODS: A case study involving a fatal incident was surveyed using three-dimensional laser scanning, and subsequently recreated through virtual and physical models. The created models were then utilized in both accident investigation and legal process, to explore the technologies used in this setting. RESULTS: Benefits include explanation of the event and environment, incident reconstruction, preservation of evidence, reducing the need for site visits, and testing of theories. Drawbacks include limited technology within courtrooms, confusion caused by models, cost, and personal interpretation and acceptance in the data. CONCLUSION: Laser scanning surveys can be of considerable use in jury trials, for example, in case the location supports the use of a high-definition survey, or an object has to be altered after the accident and it has a specific influence on the case and needs to be recorded. However, consideration has to be made in its application and to ensure a fair trial, with emphasis being placed on the facts of the case and personal interpretation controlled.

Comparative bioavailability and antimicrobial activity of cetylpyridinium chloride mouthrinses in vitro and in vivo.

PURPOSE: Commercialized cetylpyridinium chloride (CPC) mouthrinses were compared for antimicrobial substantivity/bioavailability in an in vitro disk retention assay (DRA) and clinical antimicrobial activity in vivo in the plaque glycolysis and regrowth method (PGRM). METHODS: Formulations compared in this testing included commercially available CPC mouthrinses: Crest Pro Health (CPH), (containing 700 ppm formulated CPC); Colgate Total Puerto Rico (CT450), (containing 450 ppm formulated CPC); Colgate Total US (CT750), (containing 750 ppm formulated CPC); and Scope Mouthwash (SCP), (containing 450 ppm formulated CPC). A water control (CTR) was included in one of the PGRM clinical trials. Two separate clinical PGRM studies employed a controlled, double-blind, randomized, crossover design where qualified adult PGRM panelists were supplied with acclimation NaF dentifrice for use throughout the trials. On treatment days, subjects sampled baseline plaque and then rinsed with assigned mouthrinse following morning toothbrushing. Treated plaque samples were collected 15 and 45 minutes after rinsing. Sampled plaques were vortexed, normalized for biomass and incubated under standard conditions to assess glycolysis. pH response of treated plaques in incubation buffers were compared to baseline untreated plaque values and an Area Under Curve (AUC) composite/aggregate analysis of glycolysis inhibition was used for treatment comparisons. A laboratory disk retention substantivity/bioavailability assay measured adsorption affinity of CPC in mouthrinse for anionic cellulose disks in vitro. RESULTS: Clinical PGRM studies showed significant differences in antibacterial clinical efficacy of commercialized mouthrinses. Combining clinical study results reveals rank ordered efficacy CPH > CT750 > SCP > CT450 > CTR. Comparison of DRA to PGRM glycolysis showed a linear relation highlighting correlation of CPC bioavailability to clinical antimicrobial performance of CPC mouthrinses.

Topical oral cavity pharmacokinetic modeling of a stannous fluoride dentifrice: an unusual two compartment model.

A pharmacokinetic model was developed describing the pharmacokinetics of stannous fluoride in human subjects after oral topical application of a stannous fluoride dentifrice. Twenty subjects participated in an investigation of an experimental dentifrice. Subjects rinsed their mouths with the experimental dentifrice slurry. Saliva and plaque samples were obtained from the subjects at various times up to 6 h after administration. Samples were analyzed for total tin content, used as an analytical marker for the active stannous fluoride ingredient, using a graphite furnace atomic absorption spectrometer. The modeling indicates that there is an obvious kinetic relationship between saliva and plaque compartments and that stannous fluoride is very well retained in and slowly released from plaque (and oral surfaces) into saliva. Additionally, both compartments are simultaneously loaded during administration unlike typical systemic drug behavior, and the elimination rate "constant" from the central compartment (saliva) changes due to changes in salivary flow. Stannous fluoride is cleared from saliva rapidly but very well retained in gingival plaque. The model with simultaneous loading of plaque and saliva describes these observations and may account for the prolonged antiplaque and antigingivitis benefits of stannous fluoride.

Sustained antibacterial actions of a new stabilized stannous fluoride dentifrice containing sodium hexametaphosphate.

Stannous fluoride has been used as a chemotherapeutic agent for years to improve oral health. The benefits of stannous fluoride in controlling caries, plaque, and gingivitis are directly associated with its antimicrobial actions. Recently, a novel dentifrice was developed that combines stannous fluoride with an anticalculus agent, sodium hexa. metaphosphate. A series of independent evaluations were conducted to assess the long-lasting antimicrobial activity of stannous fluoride in the new stannous fluoride/sodium hexametaphosphate dentifrice: an in vitro Live/Dead assay; an in vivo Plaque Glycolysis and Regrowth Model study; a rapid in vitro salivary bacteria metabolic activity study; and a 12-hour in vivo tin-retention study. In the Live/Dead study, the new stannous fluoride/sodium hexametaphosphate dentifrice killed approximately 90% to 99% of the salivary microbes 16 hours after a single exposure. Similarly, the stannous fluoride dentifrice produced statistically significant reductions in plaque acid production and plaque regrowth activity compared to plaque treated with a standard fluoride dentifrice at all time intervals measured after product exposure (15 and 45 minutes). Results from the final two studies collectively demonstrated the presence of total soluble tin, which serves as a marker for the active stannous fluoride, at levels above the minimum concentration for inhibition of salivary bacteria metabolic activity 12 hours posttreatment. These findings confirm the long-lasting antibacterial action of the new stannous fluoride dentifrice, which serves as a basis for its therapeutic benefits.