Biomedical subjects

James C Ragain

Publications and source records attributed to James C Ragain.

7 recordsLinked to original sources

PubMed2006

Evaluation of field dental equipment in a deployment environment.

Dental officers and technicians must have reliable, durable, well-performing field dental equipment to enable them to provide dental care to deployed troops in operational environments. Unfortunately, no organized program exists to test such equipment before its purchase and use in the field. This article presents the results of a project conducted by the Naval Institute for Dental and Biomedical Research and the Air Force Dental Evaluation and Consultation Service to evaluate commercially available field dental equipment through laboratory testing and clinical-user evaluations in theater. The purpose of this 2-year project was to identify the best-performing and most cost-effective field dental equipment for possible future procurement. Initial laboratory testing was performed at the Naval Institute for Dental and Biomedical Research, and the equipment was then shipped to Kuwait for in-theater environmental and clinical-user testing. A seven-member scientific team of military dental officers and technicians was deployed for 1 month to perform in-theater testing under regional environmental conditions and to coordinate clinical-user evaluations. The testing provided beneficial results by identifying equipment that performed properly and equipment that exhibited shortcomings serious enough to render it inadequate for operational use. It is recommended that the project serve as a model for future testing and evaluation of medical/dental equipment by all of the military services.

Dental Equipment↗

PubMed2005

Comparison of two video-imaging instruments for measuring volumetric shrinkage of dental resin composites.

OBJECTIVES: The purpose of this study was to measure the polymerization shrinkage of three dental resin composites using two commercially available video-imaging devices to determine if the devices produced equivalent results. METHODS: Small, semi-spherical specimens of a microhybrid (Venus), microfill (Filtek A110), and flowable (Esthet*X Flow) resin composite were manually formed and light activated for 40s using a light-curing unit. The volumetric polymerization shrinkage of fifteen specimens of each brand of resin composite was measured using the AcuVol and the Drop Shape Analysis System model DSA10 Mk2 (DSAS) video-imaging devices. Mean volumetric shrinkage values were calculated for each resin composite and equivalence was evaluated using the two one-sided tests approach. Differences between the means that were less than approximately 5% of the observed shrinkage were considered indicative of clinical equivalence. RESULTS: Mean volumetric shrinkage values measured for the resin composites were: Venus (AcuVol, 3.07+/-0.07%; DSAS, 2.90+/-0.07%); Filtek A110 (AcuVol, 2.26+/-0.10%; DSAS, 2.25+/-0.09%); and Esthet*X Flow (AcuVol, 5.01+/-0.17%; DSAS, 5.14+/-0.11%). Statistical analysis revealed that the two imaging devices produced equivalent results for Filtek A110 and Esthet*X Flow but not for Venus. CONCLUSIONS: Video-imaging systems provide an easy method for measuring volumetric shrinkage of resin composites. As with other methods for measuring volumetric shrinkage, however, they are best used to comparatively measure different materials within the same laboratory.

Acrylic Resins↗

PubMed2005

Dental sealant longevity in a cohort of young U.S. naval personnel.

BACKGROUND: The U.S. Navy emphasizes caries prevention and encourages the placement of dental sealants on the caries-susceptible teeth of patients at risk of developing caries. The authors analyzed dental records to assess the longevity of dental sealants placed in naval personnel. METHODS: A cluster sample of dental records from 1,123 personnel who entered naval service in 1997 was drawn from eight Navy dental treatment facilities. The authors determined the number of sealants provided, the number of sealants that failed over the observation period (1997-2001), the dates of sealant failure and the longevity of sealants placed during and after recruit training. RESULTS: A total of 319 personnel received sealants during their first two years of service. The authors evaluated 1,467 sealed teeth. They followed the sealants for an average of 35 months. They noted 179 sealant failures in 102 subjects; 69 previously sealed teeth required sealant replacement, and 110 sealed teeth required restoration of the occlusal surface. Among those sealants that failed, the mean length of time from placement to failure was 26 months. Sealant failure rates were significantly higher among subjects at moderate risk or high risk of developing caries than among subjects at low risk. CONCLUSIONS: After an average of 35 months, 87.8 percent of the sealants placed in this population were retained and functional. Subjects who were at moderate or high risk of developing caries demonstrated significantly higher sealant failure rates than those at low risk of developing caries. CLINICAL IMPLICATIONS: Dental sealants can be retained successfully in adults. They should be considered a viable treatment alternative for adult patients who are susceptible to caries; however, patients at elevated risk of developing caries may require more frequent re-evaluation and maintenance to achieve maximum benefit.

Adolescent↗

PubMed2005

Disinfectants' effect on mercury release from amalgam.

BACKGROUND: Mercury environmental discharge is under increased scrutiny by the U.S. Environmental Protection Agency (EPA). Dental amalgam should be processed properly to prevent an additional environmental burden. Some processing agencies require that submitted amalgam be noninfectious. Investigations have demonstrated that oxidizing disinfectants mobilize mercury from amalgam into solution and add mercury to the environmental burden if it is disposed of improperly. The authors conducted a study to evaluate the effect of representative disinfectants on amalgam mercury release. METHODS: The authors sized a high-copper spherical amalgam alloy to match that typically found in dental unit suction traps. They exposed 20 grams of the alloy to several disinfectant solutions and evaluated the filtered supernatant solution for mercury content. RESULTS: Chlorine disinfectant materials discharged the most mercury ions, followed by bromide, iodophor, peroxide/peracetic acid and phenolic disinfectants. The quaternary ammonium compound did not discharge mercury ions above the detection limit (0.2 parts per billion) into solution. CONCLUSIONS: A quaternary ammonium compound did not mobilize mercury ions into solution when used as a disinfectant agent for amalgam. Chlorine disinfectants mobilized mercury ions the most, followed by bromide, iodophor, peroxide/peracetic acid and phenolic disinfectants. CLINICAL IMPLICATIONS: Dentists are obligated to be good environmental stewards and should follow practices that reduce environmental mercury release. Dental personnel should be aware that oxidizing disinfectants mobilize mercury ions into solution, which will be added to the environment if they are processed improperly. If required by processing, dental personnel should consider the different oxidizing effects of commonly used disinfectants.

Anti-Infective Agents, Local↗

PubMed2004

Statistical estimation of resin composite polymerization sufficiency using microhardness.

With respect to determining sub-surface resin polymerization sufficiency, this study compared a traditional method of applying linear regression to bottom- to top-surface Knoop hardness ratios to an alternative method based on nonlinear regression. Inverse linear regression on ratios was used to estimate the exposure duration required for 80% bottom-surface hardness with respect to the top, in six light-by-material groups. Alternatively, a one-phase, two-parameter, exponential association of the form Y=Y(max)(1-e(-kt)) (where Y(max) is maximum hardness, k is a rate constant, and t is exposure duration), was used to model hardness. Inverse nonlinear regression estimated, for each condition, the exposure duration required for the bottom surface to achieve 80% of corresponding condition (light and material) top-surface Y(max). Mathematically, analysis of ratios was demonstrated to yield potentially less precise and biased estimates. Nonlinear regression yielded better statistical fit and provided easily accessible tests for differences in k across light-system groups. Another recently proposed nonlinear model for polymerization, Y=Y(max)kt(n)/(1+kt(n)), was also considered. While this new model has substantially greater phenomenological and mechanistic justification, we found that the model-fitting process was more sensitive to initial parameter values and sometimes yielded untenable results when applied to our data. However, we believe that these problems would not occur if sample points are well distributed across a wide range of exposure durations, and that the model, Y=Y(max)kt(n)/(1+kt(n)), should be considered for such data sets.

Analysis of Variance↗

PubMed2003

Diagnosis of militarily relevant diseases using oral fluid and saliva antibodies: fluorescence polarization immunoassay.

This laboratory is developing fluorescence polarization (FP) methods as diagnostic tools to assay antibodies in saliva and other oral fluids. FP provides quantitation of molecular interaction, such as antigen-antibody binding, of a single, small-volume sample in real time and without prior separation of components such as blood cells. There is potential for wide-spread use of these homogeneous assays as noninvasive tests, especially as more compact, simplified fluorescence polarimeters become available. FP tests can be designed that are applicable to a wide spectrum of microorganisms and may be used in a clinic or far-forward deployed setting to aid in diagnosis of disease or verification of vaccination. Rapid salivary diagnostics, including FP, have been identified by the Office of Naval Research as requirements for future naval capabilities in basic and applied medical research for warfighter protection in casualty prevention. The applications of FP salivary diagnostics for determination of tuberculosis exposure and of anthrax immunization status are discussed as examples.

Anthrax↗

PubMedDate not supplied

Waterline biofilm and the dental treatment facility: a review.

Biofilms are well-organized communities of cooperating microorganisms that can include bacteria, protozoa, diatoms, and fungi. Surveys of dental unit waterlines (DUWLs) indicate that biofilm formation is a universal problem and that environmental and human-derived opportunistic pathogens can be cultured consistently from biofilms retrieved from DUWLs and other dental devices. Although the health risks presented by waterline bacterial colonization have yet to be adequately addressed, professional and ethical considerations indicate that steps should be taken to improve the quality of DUWLs. To address these concerns, the Council on Scientific Affairs of the ADA recently published a list of products cleared by the FDA to control dental waterline contamination. The goal of this article is to increase the awareness of potential health risks posed by biofilm formation and provide information on techniques and devices designed to control the microbial contamination of DUWLs.

Bacteria↗