The effect of simulated field storage conditions on the accuracy of rapid user-friendly blood pathogen detection kits.

Being able to test for the presence of blood pathogens at forward locations could reduce morbidity and mortality in the field. Rapid, user-friendly blood typing kits for detecting Human Immunodeficiency Virus (HIV), Hepatitis C Virus (HCV), and Hepatitis B Virus (HBV) were evaluated to determine their accuracy after storage at various temperatures/humidities. Rates of positive tests of control groups, experimental groups, and industry standards were compared (Fisher's exact chi2, p < or = 0.05). Compared to the control group, 2 of 10 HIV detection devices were adversely affected by exposure to high temperature/high humidity or high temperature/low humidity. With one exception, none of the environmentally exposed HCV or HBV detection devices exhibited significant differences compared to those stored under control conditions. For HIV, HCV, and HBV devices, there were differences compared to the industry standard. Collectively, this evaluation of pathogen detection kits revealed that diagnostic performance varies among products and storage conditions, and that the tested products cannot be considered to be approved for use to screen blood, plasma, cell, or tissue donors.

Accuracy of user-friendly blood typing kits tested under simulated military field conditions.

Rapid user-friendly ABO-Rh blood typing kits (Eldon Home Kit 2511, ABO-Rh Combination Blood Typing Experiment Kit) were evaluated to determine their accuracy when used under simulated military field conditions and after long-term storage at various temperatures and humidities. Rates of positive tests between control groups, experimental groups, and industry standards were measured and analyzed using the Fisher's exact chi-square method to identify significant differences (p < or = 0.05). When Eldon Home Kits 2511 were used in various operational conditions, the results were comparable to those obtained with the control group and with the industry standard. The performance of the ABO-Rh Combination Blood Typing Experiment Kit was adversely affected by prolonged storage in temperatures above 37 degrees C. The diagnostic performance of commercial blood typing kits varies according to product and environmental storage conditions.

Determination of minimum suction level necessary for field dental units.

A significant problem with most field dental units is that their suction is too weak to effectively remove debris from the mouth. The purpose of this study was to determine the minimum clinically acceptable suction level for routine dentistry. A vacuum pump was connected to a high-volume dental evacuation line in a simulated clinical setting and different suction airflow rates were evaluated by nine evaluator dentists for their capability to effectively remove amalgam debris and water. Airflow levels were rated as "clinically acceptable" or "clinically unacceptable" by each evaluator. Data were analyzed using a chi2 test for trend. Analysis indicated a significant linear trend between airflow and ratings (p < 0.0001). The first airflow level considered by all evaluators as producing clinically acceptable suction was 4.5 standard cubic feet per minute (0.127 standard cubic meters per minute). This value should be the minimum level required for all military field dental units.

Portable dental equipment: dental units and x-ray equipment.

Portable dental equipment makes it possible for clinicians to provide dental care to patients who are unable to travel to a traditional dental clinic. Nonambulatory, homebound, and institutionalized patients benefit greatly when portable equipment is used to address their dental treatment needs on-site. In recent years, more brands of portable equipment have been introduced to the market, some of which are quite sophisticated in terms of their design and uses. This article seeks to describe two kinds of commercially available portable equipment--dental units and x-ray devices--and to discuss their capabilities and features.

Stability of user-friendly blood typing kits stored under typical military field conditions.

To help preserve in-theater strength within deployed military units, commercially available, rapid, user-friendly ABO-Rh blood typing kits were evaluated to determine their stability in storage conditions commonly encountered by the warfighter. Methods for environmental exposure testing were based on MIL-STD-810F. When Eldon Home Kits 2511 were exposed to various temperature/relative humidity conditions, the results were comparable to those obtained with the control group and those obtained with industry-standard methods. For the ABO-Rh Combination Blood Typing Experiment Kits, 2 of the exposure treatments rendered them unusable. In addition, a third set of exposure treatments adversely affected the kits, resulting in approximately 30% blood type misclassifications. Collectively, this evaluation of commercial blood typing kits revealed that diagnostic performance can vary between products, lots, and environmental storage conditions.

The release of mercury from amalgam restorations and its health effects: a review.

Amalgam has successfully been used as a restorative material in dentistry for over a century. It has proven to be a cost-effective, wear-resistant material which, when properly placed, can provide many years of service. However, amalgam's popularity has decreased in recent years due, in part, to patient concerns about its potential for adversely affecting their health. Other reasons for its reduced use include the increased emphasis on more esthetic restorative materials and environmental concerns regarding the amount of mercury discharged into wastewater from dental offices. Controversy persists about amalgam's possible role in causing health problems due to its release of mercury. Although conclusive evidence is lacking that directly correlates amalgam with adverse health effects, clinicians should remain knowledgeable about mercury release from amalgam in order to intelligently address their patients' concerns. This article reviews the latest published scientific literature to provide this information.

Hardness of three resin-modified glass-ionomer restorative materials as a function of depth and time.

STATEMENT OF THE PROBLEM: The polymerization of bulk-placed resin-modified glass-ionomer (RMGI) restoratives is compromised when penetration of the curing light is limited because of the materials' thickness. It is unknown if additional post light-curing resin polymerization and/or glass-ionomer setting occurs over time to ensure adequate polymerization. PURPOSE: The primary objective was to evaluate the depth of cure of various thicknesses of RMGI restorative products over 1 year using Knoop hardness (KH) testing. MATERIALS AND METHODS: The materials were placed in Delrin molds having an internal diameter of 5.0 mm and heights of 2, 3, 4, and 5 mm and were photopolymerized with a halogen light-curing unit. Five specimens of each depth were prepared for each time period evaluated. Specimens were stored in darkness at 37 +/- 2 degrees C and 98 +/- 2% humidity until being tested at 24 hours, 1 week, and 1, 3, 6, 9, and 12 months after fabrication. Mean KH values were calculated for the bottom and top surfaces of each thickness group and used to determine bottom/top hardness ratios. Data were compared using two-way analysis of variance (factors of time, thickness) at a 0.05 significance level with Scheffé's post hoc analysis, where required. RESULTS: The materials had relatively stable top surface KH, which permitted valid assessment of changes in bottom surface KH over time. The bottom surface KH of some RMGIs changed significantly over time (p < 0.001), but degrees of change were material dependent. Certain RMGIs demonstrated a potential for statistically significant post light-activation hardening; however, that too was material dependent. As compared with top surface KH, deeper layers of the thicker RMGI specimens consistently failed to achieve an adequate degree of polymerization. CONCLUSION: Although certain RMGI materials demonstrate a potential for post light-activation chemically initiated resin polymerization and/or polyalkenoate acid/base reaction, these reactions may not be sufficient to ensure that the material is adequately polymerized for long-term success. This is particularly true when RMGI materials are placed in thicker layers where curing light penetration may be compromised. CLINICAL SIGNIFICANCE: RMGI materials should not be placed in bulk but photopolymerized in layers to ensure adequate light activation. The results of this study suggest that Photac-Fil Quick be placed in layers no thicker than 2 mm while Fuji II LC and Vitremer may be placed in layers up to 3 mm in thickness.

Metal-ceramic alloys in dentistry: a review.

PURPOSE: The purpose of this article is to review basic information about the alloys used for fabricating metal-ceramic restorations in dentistry. Their compositions, properties, advantages, and disadvantages are presented and compared. In addition to reviewing traditional noble-metal and base-metal metal-ceramic alloys, titanium and gold composite alloys are also discussed. MATERIALS AND METHODS: A broad search of the published literature was performed using Medline to identify pertinent current articles on metal-ceramic alloys as well as articles providing a historical background about the development of these alloys. Textbooks, the internet, and manufacturers' literature were also used to supplement this information. RESULTS: The review discusses traditional as well as more recently-developed alloys and technologies used in dentistry for fabricating metal-ceramic restorations. Clear advantages and disadvantages for these alloy types are provided and discussed as well as the role that compositional variations have on the alloys' performance. This information should enable clinicians and technicians to easily identify the important physical properties of each type and their primary clinical indications. CONCLUSIONS: A number of alloys and metals are available for metal-ceramic use in dentistry. Each has its advantages and disadvantages, primarily based on its specific composition. Continuing research and development are resulting in the production of new technologies and products, giving clinicians even more choices in designing and fabricating metal-ceramic restorations.

Measurement of select physical and mechanical properties of 3 machinable ceramic materials.

OBJECTIVE: To measure select physical and mechanical properties of 3 machinable ceramic materials (IPS Empress CAD, Ivoclar Vivadent; Vitablocs Mark II, Vident; Paradigm C, 3M ESPE). METHOD AND MATERIALS: The physical and mechanical properties tested were hardness (using Vickers hardness), flexural strength and modulus (with 3-point bending), fracture toughness (with Vickers hardness indentation), and coefficient of thermal expansion (using a thermomechanical analyzer). For each of the materials, 25 specimens were fabricated to test each property, except for coefficient of thermal expansion, where n = 5. For each tested property, data were analyzed using 1-way analysis of variance and Tukey Studentized range test (significance level = .05), when required for post hoc testing. RESULTS: Mean Vickers hardness ranged from 511.3 (SD 8.6) for Paradigm C to 569.3 (SD 10.2) for Vitablocs Mark II. Flexural strength was greatest for IPS Empress CAD at 137.51 (SD 23.34) MPa and least for Vitablocs Mark II at 94.08 (SD 14.21) MPa. Flexural modulus ranged from 8.65 (SD 2.24) GPa (Vitablocs Mark II) to 16.10 (SD 5.94) GPa (IPS Empress CAD). IPS Empress CAD had the highest fracture toughness at 2.18 (SD 0.30) MPa.m(1/2), while Vitablocs Mark II had the lowest at 1.37 (SD 0.22) MPa.m(1/2). Paradigm C exhibited the highest thermal expansion coefficient at 16.87 (SD 4.37) 3 10(-6)/degrees C, and Vitablocs Mark II had the lowest at 8.60 (SD 1.47) 3 10(-6)/degrees C. CONCLUSIONS: The 3 ceramic materials significantly differed in all of the properties measured. Vitablocs Mark II was the hardest of the 3 materials, and IPS Empress CAD had the greatest flexure strength, flexural modulus, and fracture toughness.

Fracture resistance of amalgam/glass-polyalkenoate open sandwich Class II restorations: an in vitro study.

OBJECTIVE: To investigate the effect of two glass-polyalkenoate restorative materials used as root-dentin replacements on the fracture strength of Class II amalgam restorations. MATERIALS AND METHODS: Class II slot preparations extending 2mm apical to the cemento-enamel junction were made in 30 teeth and randomly assigned to three groups. Group 1 (Control): restored entirely with amalgam (Tytin, Sybron Kerr, Orange, CA, USA). Group 2: The root-dentin area was restored with a viscous conventional glass-polyalkenoate restorative material (Fuji IX GP, GC America, Alsip, IL, USA), and the remainder of the preparation restored with amalgam. Group 3: The root-dentin area was restored with a resin-modified glass-polyalkenoate restorative material (Fuji II LC, GC America) and the remainder restored with amalgam. The amalgam restorations were loaded in compression to failure and the data analyzed using one-way ANOVA (alpha=0.05). RESULTS: No significant differences in fracture strength were found. CONCLUSION: Root-dentin replacement with the tested glass-polyalkenoate materials did not affect the fracture strength of Class II amalgam restorations.

Rapid point-of-care test to detect broad ranges of protective antigen-specific immunoglobulin G concentrations in recipients of the U.S.-licensed anthrax vaccine.

Currently, there is no routine monitoring of an immune response to the anthrax vaccine. Simple on-site tests are needed to evaluate the antibody response of anthrax-vaccinated individuals in the Armed Forces and others at high risk. Using a prototype lateral flow assay (LFA) (R. E. Biagini, D. L. Sammons, J. P. Smith, B. A. MacKenzie, C. A. F. Striley, J. E. Snawder, S. A. Robertson, and C. P. Quinn, Clin. Vaccine Immunol. 13:541-546, 2006), we investigated the agreement between a validated anthrax protective antigen (PA) immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) and the LFA for 335 unvaccinated and vaccinated subjects. We also investigated the performance of the LFA under the following conditions: thermal shock (i.e., thermal cycling between temperature extremes), high temperature/high relative humidity, high temperature/low relative humidity, and low temperature/low relative humidity. With the anti-PA ELISA used as a standard, the LFA was shown to be optimally diagnostic at 11 microg/ml anti-PA-specific IgG. At this concentration, the LFA specificity and sensitivity were 98% (95% confidence interval [CI], 97% to 100%) and 92% (CI, 88% to 97%), respectively. Receiver operating characteristic curve analysis yielded an area under the curve value of 0.988 (CI, 0.976 to 1.00), suggesting that the LFA is an extremely accurate diagnostic test. For < or = 4 or > or = 50 microg/ml PA-specific IgG, the LFA results for each environmental condition were identical to those obtained in the laboratory. These data indicate that this rapid point-of-care test would be a feasible tool in monitoring the serological antibody responses of individuals that have been vaccinated against anthrax.

Clinical user evaluation of field dental equipment under military deployment conditions.

The purpose of this work was to evaluate the clinical performance of a number of types of field (i.e., portable) dental equipment used under actual military deployment conditions. This equipment is often used under demanding field conditions where temperature, humidity, and air quality are not controlled. 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 at military deployment sites. The purpose of the study was to identify the best-performing and most cost-effective field dental equipment for possible operational use by the U.S. Navy. Initial laboratory testing was performed at the Naval Institute for Dental and Biomedical Research and the equipment was then shipped to Okinawa, Japan, where it was tested by military dentists and assistants under deployment conditions. The testing provided beneficial results by identifying equipment that performed properly and equipment that exhibited shortcomings serious enough to render it inappropriate for field use.

Mineral trioxide aggregate material use in endodontic treatment: a review of the literature.

OBJECTIVE: The purpose of this paper was to review the composition, properties, biocompatibility, and the clinical results involving the use of mineral trioxide aggregate (MTA) materials in endodontic treatment. METHODS: Electronic search of scientific papers from January 1990 to August 2006 was accomplished using PubMed and Scopus search engines (search terms: MTA, GMTA, WMTA, mineral AND trioxide AND aggregate). RESULTS: Selected exclusion criteria resulted in 156 citations from the scientific, peer-reviewed dental literature. MTA materials are derived from a Portland cement parent compound and have been demonstrated to be biocompatible endodontic repair materials, with its biocompatible nature strongly suggested by its ability to form hydroxyappatite when exposed to physiologic solutions. With some exceptions, MTA materials provide better microleakage protection than traditional endodontic repair materials using dye, fluid filtration, and bacterial penetration leakage models. In both animal and human studies, MTA materials have been shown to have excellent potential as pulp-capping and pulpotomy medicaments but studies with long-term follow-up are limited. Preliminary studies suggested a favorable MTA material use as apical and furcation restorative materials as well as medicaments for apexogenesis and apexification treatments; however, long-term clinical studies are needed in these areas. CONCLUSION: MTA materials have been shown to have a biocompatible nature and have excellent potential in endodontic use. MTA materials are a refined Portland cement material and the substitution of Portland cement for MTA products is presently discouraged. Existing human studies involving MTA materials are very promising, however, insufficient randomized, double-blind clinical studies of sufficient duration exist involving MTA for all of its clinical indications. Further clinical studies are needed in these areas.

Development and testing of a novel forward-deployable dental dressing.

The purpose of this study was to measure select properties of four temporary filling materials suitable for use in treating minor dental emergencies in the field. Specimens were made of each of the following four materials: intermediate restorative material, Fuji IX GP Fast, Ketac-Molar Quick, and the forward-deployable dental dressing recently developed by the Naval Institute for Dental and Biomedical Research. Twenty-fours hours after specimen fabrication, five properties (hardness, compressive strength, diametral tensile strength, flexural strength, and flexural modulus) were measured for each of the materials and compared using analysis of variance and Tukey-Kramer tests to determine whether significant differences existed among the materials (alpha = 0.05). Data analysis revealed that significant differences existed among the products for all of the properties tested. The forward-deployable dental dressing's properties compared favorable with and, in many cases exceeded those of intermediate restorative material, Fuji IX GP Fast, and Ketac-Molar Aplicap Quick.

Current update on portable dental equipment.

The dental care needs of the elderly are increasing as their population grows. For some of the elderly (eg, the nonambulatory, homebound, institutionalized), accessing dental care is a problem because they are unable to visit a traditional dental clinic. In the past, dental care has been taken to the homebound or institutionalized elderly by dentists using portable dental equipment. However, the perception that such equipment is difficult or impossible to obtain has limited the availability of on-site care. The purpose of this article is to describe various types of portable dental equipment and their features so that dentists interested in providing care to this group of patients are aware of them.

Accuracy of LED and halogen radiometers using different light sources.

PURPOSE: To determine the accuracy of commercially available, handheld light-emitting diode (LED) and halogen-based radiometers using LED and quartz-tungsten-halogen (QTH) curing lights with light guides of various diameters. METHODS: The irradiance of an LED curing light (L.E. Demetron 1, SDS/Kerr, Orange, CA, USA) and a QTH curing light (Optilux 501, SDS/Kerr) were measured using multiple units of an LED (Demetron L.E.D. Radiometer, SDS/Kerr) and a halogen radiometer (Demetron 100, SDS/Kerr) and compared with each other and to a laboratory-grade power meter (control). Measurements were made using five light guides with distal light guide diameters of 4, 7, 8, 10, and 12.5 mm. For each light guide, five readings were made with each of three radiometers of each radiometer type. Data were analyzed with two-way analysis of variance/Tukey; alpha = 0.05. RESULTS: In general, both handheld radiometer types exhibited significantly different irradiance readings compared with the control meter. Additionally, readings between radiometer types were found to differ slightly, but were correlated. In general, the LED radiometer provided slightly lower irradiance readings than the halogen radiometer, irrespective of light source. With both types of handheld radiometers, the use of the larger-diameter light guides tended to overestimate the irradiance values as seen in the control, while smaller-diameter light guides tended to underestimate. CLINICAL SIGNIFICANCE: The evaluated LED or halogen handheld radiometers may be used interchangeably to determine the irradiance of both LED and QTH visible-light-curing units. Measured differences between the two radiometer types were small and probably not clinically significant. However, the diameter of light guides may affect the accuracy of the radiometers, with larger-diameter light guides overestimating and smaller-diameter guides underestimating the irradiance value measured by the control instrument.

Effect of humidity on the volumetric polymerization shrinkage of resin restorative materials.

This study measured the volumetric polymerization shrinkage of three resin restorative materials under ambient (that is, room) relative humidity conditions and compared it with shrinkage occurring under a higher humidity condition that simulated the oral cavity. Small, semi-spherical specimens of a compomer, microfill composite, and flowable microhybrid composite were formed and light-activated using a halogen photocuring unit. The volumetric polymerization shrinkage of 15 specimens of each product was measured using a drop shape analysis unit for the relative humidity level of the ambient room (58.6 +/- 5.9%) and a higher humidity level that simulated the oral cavity (98.0 +/- 2.9%). Mean volumetric shrinkage values were calculated for each resin composite and the data were analyzed using a two-way analysis of variance (alpha = 0.05) to determine if significant differences existed between the amount of volumetric polymerization shrinkage that occurred under ambient room humidity conditions and the amount that occurred under simulated intraoral humidity conditions. Statistical analysis indicated that there was no significant difference (p = 0.17).

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.

Volumetric polymerization shrinkage of resin composites under simulated intraoral temperature and humidity conditions.

This study measured the volumetric shrinkage of resin composites polymerized under temperature and humidity conditions simulating the oral cavity and compared them to those occurring under ambient room conditions. Small, semispherical specimens of a microhybrid (Z100), microfill (Filtek A110) and flowable microhybrid (4 Seasons Flow) resin composite were manually formed and light activated for 40 seconds using a halogen light-curing unit (Spectrum Curing Light). The volumetric polymerization shrinkage of 10 specimens of each brand of resin composite was measured using a drop shape analysis unit (Drop Shape Analysis System, model DSA10 Mk2) under each of two temperature/relative humidity conditions: room conditions (22 +/- 2 degrees C and 60 +/- 5%) and those simulating intraoral conditions (35 degrees C and 92 +/- 5%). Mean volumetric shrinkage values were calculated for each resin composite and the data were analyzed using two-way analysis of variance and t-test (a=0.05) to determine if significant differences existed between the amount of volumetric polymerization shrinkage that occurred under ambient room conditions and that which occurred under simulated intraoral conditions. Mean volumetric shrinkage values measured for the resin composites were: 2.26 +/- 0.04% (ambient) and 2.61 +/- 0.04% (intraoral) for Z100; 1.96 +/- 0.04% (ambient) and 2.28 +/- 0.04% (intraoral) for Filtek A110 and 4.53 +/- 0.06% (ambient) and 5.34 +/- 0.05% (intraoral) for 4 Seasons Flow. For each resin composite, statistical analysis indicated that the amount of volumetric shrinkage measured under simulated intraoral conditions was significantly greater than what was measured under ambient room conditions (p<0.0001).

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.