Observation of Azimuth-Dependent Suppression of Hadron Pairs in Electron Scattering off Nuclei.

We present the first measurement of dihadron angular correlations in electron-nucleus scattering. The data were taken with the CLAS detector and a 5.0 GeV electron beam incident on deuterium, carbon, iron, and lead targets. Relative to deuterium, the nuclear yields of charged-pion pairs show a strong suppression for azimuthally opposite pairs, no suppression for azimuthally nearby pairs, and an enhancement of pairs with large invariant mass. These effects grow with increased nuclear size. The data are qualitatively described by the gibuu model, which suggests that hadrons form near the nuclear surface and undergo multiple scattering in nuclei.These results show that angular correlation studies can open a new way to elucidate how hadrons form and interact inside nuclei.

Surgery Versus 5% Imiquimod for Nodular and Superficial Basal Cell Carcinoma: 5-Year Results of the SINS Randomized Controlled Trial.

We previously reported modest clinical 3-year benefit for topical imiquimod compared with surgery for superficial or nodular basal cell carcinoma at low-risk sites in our noninferiority randomized controlled SINS trial. Here we report 5-year data. Participants were randomized to imiquimod 5% cream once daily (superficial basal cell carcinoma, 6 weeks; nodular basal cell carcinoma, 12 weeks) or excisional surgery (4-mm margin). The primary outcome was clinical absence of initial failure or signs of recurrence at the 3-year dermatology review. Five-year success was defined as 3-year success plus absence of recurrences identified through hospital, histopathology, and general practitioner records. Of 501 participants randomized, 401 contributed to the modified intention-to-treat analyses at year 3 (primary outcome), 383 (96%) of whom had data at year 5. Five-year success rates for imiquimod were 82.5% (170/206) compared with 97.7% (173/177) for surgery (relative risk of imiquimod success = 0.84, 95% confidence interval = 0.77-0.91, P < 0.001). These were comparable to year 3 success rates of 83.6% (178/213) and 98.4% (185/188) for imiquimod and surgery, respectively. Most imiquimod treatment failures occurred in year 1. Although surgery is clearly superior to imiquimod, this study shows sustained benefit for lesions that respond early to topical imiquimod.

Nocturia Work Productivity and Activity Impairment Compared with Other Common Chronic Diseases.

OBJECTIVES: The International Continence Society defines nocturia as the need to void one or more times during the night, with each of the voids preceded and followed by sleep. The chronic sleep disturbance and sleep deprivation experienced by patients with nocturia affects quality of life, compromising both mental and physical well-being. This paper aims to characterise the burden of nocturia by comparing published data from patients with nocturia with data from patients with any of 12 other common chronic conditions, specifically focusing on its impact on work productivity and activity impairment, as measured by the instrument of the same name (WPAI). METHODS: A systematic literature review of multiple data sources identified evaluable studies for inclusion in the analysis. Study eligibility criteria included use of the WPAI instrument in patients with one of a predefined list of chronic conditions. We assessed the quality of each included study using the Newcastle-Ottawa scale and extracted basic study information, work and activity impairment data. To assess how work and activity impairment from nocturia compares with impairment from other common chronic diseases, we conducted two data syntheses (pooled and unpooled). RESULTS: The number of evaluable studies and the range of overall work productivity impairment reported, respectively, were as follows: nocturia (3; 14-39 %), overactive bladder (5; 11-41 %), irritable bowel syndrome/constipation (14; 21-51 %), gastroesophageal reflux disease (GERD) (13; 6-42 %), asthma/allergies (11; 6-40 %), chronic obstructive pulmonary disease (COPD) (7; 19-42 %), sleep problems (3; 12-37 %), arthritis (13; 21-69 %), pain (9; 29-64 %), depression (4; 15-43 %) and gout (2; 20-37 %). CONCLUSIONS: The overall work productivity impairment as a result of nocturia is substantial and was found to be similar to impairment observed as a result of several other more frequently researched common chronic diseases. Greater awareness of the burden of nocturia, a highly bothersome and prevalent condition, will help policy makers and healthcare decision makers provide appropriate management of nocturia.

Plant species effects on soil nutrients and chemistry in arid ecological zones.

The presence of vegetation strongly influences ecosystem function by controlling the distribution and transformation of nutrients across the landscape. The magnitude of vegetation effects on soil chemistry is largely dependent on the plant species and the background soil chemical properties of the site, but has not been well quantified along vegetation transects in the Great Basin. We studied the effects of plant canopy cover on soil chemistry within five different ecological zones, subalpine, montane, pinyon-juniper, sage/Mojave transition, and desert shrub, in the Great Basin of Nevada all with similar underlying geology. Although plant species differed in their effects on soil chemistry, the desert shrubs Sarcobatus vermiculatus, Atriplex spp., Coleogyne ramosissima, and Larrea tridentata typically exerted the most influence on soil chemistry, especially amounts of K(+) and total nitrogen, beneath their canopies. However, the extent to which vegetation affected soil nutrient status in any given location was not only highly dependent on the species present, and presumably the nutrient requirements and cycling patterns of the plant species, but also on the background soil characteristics (e.g., parent material, weathering rates, leaching) where plant species occurred. The results of this study indicate that the presence or absence of a plant species, especially desert shrubs, could significantly alter soil chemistry and subsequently ecosystem biogeochemistry and function.

Surgical excision versus imiquimod 5% cream for nodular and superficial basal-cell carcinoma (SINS): a multicentre, non-inferiority, randomised controlled trial.

BACKGROUND: Basal-cell carcinoma is the most common form of skin cancer and its incidence is increasing worldwide. We aimed to assess the effectiveness of imiquimod cream versus surgical excision in patients with low-risk basal-cell carcinoma. METHODS: We did a multicentre, parallel-group, pragmatic, non-inferiority, randomised controlled trial at 12 centres in the UK, in which patients were recruited between June 19, 2003, and Feb 22, 2007, with 3 year follow-up from June 26, 2006, to May 26, 2010. Participants of any age were eligible if they had histologically confirmed primary nodular or superficial basal-cell carcinoma at low-risk sites. We excluded patients with morphoeic or recurrent basal-cell carcinoma and those with Gorlin syndrome. Participants were randomly assigned (1:1) via computer-generated blocked randomisation, stratified by centre and tumour type, to receive either imiquimod 5% cream once daily for 6 weeks (superficial) or 12 weeks (nodular), or surgical excision with a 4 mm margin. The randomisation sequence was concealed from study investigators. Because of the nature of the interventions, masking of participants was not possible and masking of outcome assessors was only partly possible. The trial statistician was masked to allocation until all analyses had been done. The primary outcome was the proportion of participants with clinical success, defined as absence of initial treatment failure or signs of recurrence at 3 years from start of treatment. We used a prespecified non-inferiority margin of a relative risk (RR) of 0.87. Analysis was by a modified intention-to-treat population and per protocol. This study is registered as an International Standard Randomised Controlled Trial (ISRCTN48755084), and with ClinicalTrials.gov, number NCT00066872. FINDINGS: 501 participants were randomly assigned to the imiquimod group (n=254) or the surgical excision group (n=247). At year 3, 401 (80%) patients were included in the modified intention-to-treat group. At 3 years, 178 (84%) of 213 participants in the imiquimod group were treated successfully compared with 185 (98%) of 188 participants in the surgery group (RR 0.84, 98% CI 0.78-0.91; p<0.0001). No clear difference was noted between groups in patient-assessed cosmetic outcomes. The most common adverse events were itching (211 patients in the imiquimod group vs 129 in the surgery group) and weeping (160 vs 81). We recorded serious adverse events in 99 (40%) of 249 participants in the imiquimod group and 97 (42%) of 229 in the surgery group had serious adverse events, but none were regarded as related to treatment. 12 (5%) participants in the imiquimod group withdrew because of adverse events compared with four (2%) in the surgery group. INTERPRETATION: Imiquimod was inferior to surgery according to our predefined non-inferiority criterion. Although excisional surgery remains the best treatment for low-risk basal-cell carcinoma, imiquimod cream might still be a useful treatment option for small low-risk superficial or nodular basal-cell carcinoma dependent on factors such as patient preference, size and site of the lesion, and whether the patient has more than one lesion. FUNDING: Cancer Research UK.

Do increased summer precipitation and N deposition alter fine root dynamics in a Mojave Desert ecosystem?

Climate change is expected to impact the amount and distribution of precipitation in the arid southwestern United States. In addition, nitrogen (N) deposition is increasing in these regions due to increased urbanization. Responses of belowground plant activity to increases in soil water content and N have shown inconsistent patterns between biomes. In arid lands, plant productivity is limited by water and N availability so it is expected that changes in these factors will affect fine root dynamics. The objectives of this study were to quantify the effects of increased summer precipitation and N deposition on fine root dynamics in a Mojave Desert ecosystem during a 2-year field experiment using minirhizotron measurements. Root length density, production, and mortality were measured in field plots in the Mojave Desert receiving three 25 mm summer rain events and/or 40 kg N ha(-1)  yr(-1) . Increased summer precipitation and N additions did not have an overall significant effect on any of the measured root parameters. However, differences in winter precipitation resulting from interannual variability in rainfall appeared to affect root parameters with root production and turnover increasing following a wet winter most likely due to stimulation of annual grasses. In addition, roots were distributed more deeply in the soil following the wet winter. Root length density was initially higher under canopies compared to canopy interspaces, but converged toward the end of the study. In addition, roots tended to be distributed more deeply into the soil in canopy interspace areas. Results from this study indicated that increased summer precipitation and N deposition in response to climate change and urbanization are not likely to affect fine root dynamics in these Mojave Desert ecosystems, despite studies showing aboveground plant physiological responses to these environmental perturbations. However, changes in the amount and possibly distribution of winter precipitation may affect fine root dynamics.

Concurrent and lagged impacts of an anomalously warm year on autotrophic and heterotrophic components of soil respiration: a deconvolution analysis.

*Partitioning soil respiration into autotrophic (R(A)) and heterotrophic (R(H)) components is critical for understanding their differential responses to climate warming. *Here, we used a deconvolution analysis to partition soil respiration in a pulse warming experiment. We first conducted a sensitivity analysis to determine which parameters can be identified by soil respiration data. A Markov chain Monte Carlo technique was then used to optimize those identifiable parameters in a terrestrial ecosystem model. Finally, the optimized parameters were employed to quantify R(A) and R(H) in a forward analysis. *Our results displayed that more than one-half of parameters were constrained by daily soil respiration data. The optimized model simulation showed that warming stimulated R(H) and had little effect on R(A) in the first 2 months, but decreased both R(H) and R(A) during the remainder of the treatment and post-treatment years. Clipping of above-ground biomass stimulated the warming effect on R(H) but not on R(A). Overall, warming decreased R(A) and R(H) significantly, by 28.9% and 24.9%, respectively, during the treatment year and by 27.3% and 33.3%, respectively, during the post-treatment year, largely as a result of decreased canopy greenness and biomass. *Lagged effects of climate anomalies on soil respiration and its components are important in assessing terrestrial carbon cycle feedbacks to climate warming.

Atmospheric mercury exchange with a tallgrass prairie ecosystem housed in mesocosms.

This study focused on characterizing air-surface mercury Hg exchange for individual surfaces (soil, litter-covered soil and plant shoots) and ecosystem-level flux associated with tallgrass prairie ecosystems housed inside large mesocosms over three years. The major objectives of this project were to determine if individual surface fluxes could be combined to predict ecosystem-level exchange and if this low-Hg containing ecosystem was a net source or sink for atmospheric Hg. Data collected in the field were used to validate fluxes obtained in the mesocosm setting. Because of the controlled experimental design and ease of access to the mesocosms, data collected allowed for assessment of factors controlling flux and comparison of models developed for soil Hg flux versus environmental conditions at different temporal resolution (hourly, daily and monthly). Evaluation of hourly data showed that relationships between soil Hg flux and environmental conditions changed over time, and that there were interactions between parameters controlling exchange. Data analyses demonstrated that to estimate soil flux over broad temporal scales (e.g. annual flux) coarse-resolution data (monthly averages) are needed. Plant foliage was a sink for atmospheric Hg with uptake influenced by plant functional type and age. Individual system component fluxes (bare soil and plant) could not be directly combined to predict the measured whole system flux (soil, litter and plant). Emissions of Hg from vegetated and litter-covered soil were lower than fluxes from adjacent bare soil and the difference between the two was seasonally dependent and greatest when canopy coverage was greatest. Thus, an index of plant canopy development (canopy greenness) was used to model Hg flux from vegetated soil. Accounting for ecosystem Hg inputs (precipitation, direct plant uptake of atmospheric Hg) and modeled net exchange between litter-and-plant covered soils, the tallgrass prairie was found to be a net annual sink of atmospheric Hg.

Prolonged suppression of ecosystem carbon dioxide uptake after an anomalously warm year.

Terrestrial ecosystems control carbon dioxide fluxes to and from the atmosphere through photosynthesis and respiration, a balance between net primary productivity and heterotrophic respiration, that determines whether an ecosystem is sequestering carbon or releasing it to the atmosphere. Global and site-specific data sets have demonstrated that climate and climate variability influence biogeochemical processes that determine net ecosystem carbon dioxide exchange (NEE) at multiple timescales. Experimental data necessary to quantify impacts of a single climate variable, such as temperature anomalies, on NEE and carbon sequestration of ecosystems at interannual timescales have been lacking. This derives from an inability of field studies to avoid the confounding effects of natural intra-annual and interannual variability in temperature and precipitation. Here we present results from a four-year study using replicate 12,000-kg intact tallgrass prairie monoliths located in four 184-m(3) enclosed lysimeters. We exposed 6 of 12 monoliths to an anomalously warm year in the second year of the study and continuously quantified rates of ecosystem processes, including NEE. We find that warming decreases NEE in both the extreme year and the following year by inducing drought that suppresses net primary productivity in the extreme year and by stimulating heterotrophic respiration of soil biota in the subsequent year. Our data indicate that two years are required for NEE in the previously warmed experimental ecosystems to recover to levels measured in the control ecosystems. This time lag caused net ecosystem carbon sequestration in previously warmed ecosystems to be decreased threefold over the study period, compared with control ecosystems. Our findings suggest that more frequent anomalously warm years, a possible consequence of increasing anthropogenic carbon dioxide levels, may lead to a sustained decrease in carbon dioxide uptake by terrestrial ecosystems.

Statin's cost-effectiveness: a Canadian analysis of commonly prescribed generic and brand name statins.

BACKGROUND: Generic statins may be considered as a compelling treatment option for managing dyslipidemia, due to their reduced cost, compared to their brand name equivalent. However, further assessment is needed to determine whether using a particular generic statin is more cost-effective relative to other brand-name statins. OBJECTIVE: The purpose of this study is to compare the cost-effectiveness of the most commonly prescribed statins in Canada with respect to 1) lowering low-density lipoprotein cholesterol level (LDL-C) and 2) achieving National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) LDL-C goal. METHODS: The study was conducted from the perspective of Canadian payers over a 1-year time horizon. Clinical data were obtained from the STELLAR trial (n=2268) in which patients received fixed doses of rosuvastatin, atorvastatin, simvastatin and pravastatin. Brand and generic drug costs were based on wholesale acquisition costs. Relative cost-effectiveness was assessed using the net monetary benefit approach (NMB), which allows probabilistic cost-effectiveness comparison of the various treatment options over a wide range of willingness-to-pay (WTP) values for a unit of clinical effect. RESULTS: Rosuvastatin 10mg was the most cost-effective statin over the largest range of WTP values. Pravastatin 10mg was cost-effective when the clinical outcomes had little or no monetary value. Rosuvastatin 20 mg was more cost-effective at the highest end of the WTP spectrum. CONCLUSION: The result of this analysis provides evidence that prescribing generic statins in Canada does not necessarily translate into the most cost-effective option for treating dyslipidemia; especially as the monetary value of 1% decrease in LDL-C or patients achieving NCEP ATP III target increases.

Cost effectiveness of rosuvastatin in treating patients to low-density lipoprotein cholesterol goals compared with atorvastatin, pravastatin, and simvastatin (a US Analysis of the STELLAR Trial).

Statin therapy decreases low-density lipoprotein cholesterol levels and the risk of coronary heart disease but has a considerable short-term effect on health care budgets. The cost effectiveness of rosuvastatin (Crestor) has been compared with those of atorvastatin, pravastatin, and simvastatin in lowering low-density lipoprotein cholesterol levels and achieving National Cholesterol Education Program Adult Treatment Panel III low-density lipoprotein cholesterol goals. The analysis was conducted from the perspective of health care payers in the United States. Clinical data were obtained from the Statin Therapies for Elevated Lipid Levels Compared Across Doses to Rosuvastatin (STELLAR) trial. Drug costs were based on wholesale acquisition costs. Cost effectiveness was assessed with the net monetary benefit approach and a 1-year time horizon. Rosuvastatin at 10 mg, the recommended starting dose, was the most cost-effective statin over a large range of "willingness-to-pay" values for a unit of clinical effect (i.e., a 1% decrease in low-density lipoprotein cholesterol or a patient achieving the goal).

Are cost benefits of anticoagulation for stroke prevention in atrial fibrillation underestimated?

BACKGROUND AND PURPOSE: Stroke outcomes in patients with atrial fibrillation (AF) tend to be worse than those in patients without AF. The objective of this study was to evaluate whether the cost benefits of anticoagulation for stroke prevention in AF may currently be underestimated by existing economic models that do not distinguish between different stroke outcomes. METHODS: A literature review was conducted in 3 areas: (1) studies comparing stroke outcomes in AF and non-AF patients; (2) studies providing long-term cost of stroke estimates; and (3) studies modeling the cost-effectiveness of anticoagulation with a vitamin K antagonist (eg, warfarin) in AF patients. RESULTS: There is considerable evidence that stroke in AF patients has a worse outcome than in patients without AF, including higher mortality, severity, and recurrence rates, and greater functional impairment and dependency. Estimates of the long-term cost of stroke of different severities were between US 24,991 dollars for a mild stroke over 5 years and US 142,251 dollars for a major ischemic stroke over a lifetime (2004 prices). The cost of a severe ischemic stroke may typically be 3-times that of mild stroke. However, cost-effectiveness models for anticoagulation in patients with AF have used average (not AF-specific) cost-of-stroke data, and most have used stroke severity distributions derived from clinical trials, which may differ from those in clinical practice. CONCLUSIONS: Existing economic models underestimate the cost benefits of anticoagulation for stroke prevention because they do not adjust for poorer outcomes associated with cardioembolic strokes.

Smile analysis and face-bow transfer: enhancing aesthetic restorative treatment.

The objective of current aesthetic dental treatments are to enhance the patient's smile by improving the overall dental appearance. A detailed analysis of the patient's face as it relates to the three-dimensional position, shape, and color of the teeth is required to improve this appearance. A full frontal and lateral evaluation of the patient's facial form is required to successfully complete on aesthetic smile evaluation. Additional considerations include cephalometry and a thorough dental analysis. This article demonstrates a comprehensive smile analysis technique and its communication to the dental technician.

Nanoleakage at the dentin adhesive interface vs microtensile bond strength.

Excessive etching of the dentin may decrease bond strength because the adhesive may fail to completely infiltrate to the base of the over-etched demineralized collagen network. The purpose of the present study was to evaluate the influence of increasing etching times on the microtensile bond strength of Single Bond and the leakage of silver ions within the hybrid layer. After etching occlusal dentin for 15, 30, or 60 seconds with 35% phosphoric acid gel, Single Bond was applied and cured for 10 seconds. Z100 was added and cured for 60 seconds. After 24 hours of water immersion, the teeth were sectioned into slices 0.7 mm thick, and hour-glass-shaped specimens were prepared. Alternate slices were either dried for 30 minutes in air, kept wet, or they were coated with fingernail varnish except for 0.5 mm around the bonded area. Only the varnished samples were then stained with 50% AgNO3. Microtensile bond strength was tested using a Vitrodyne V-1000 universal tester. The samples of the stained group were embedded in self-curing PMMA and polished. All samples were observed with an SEM. Nanoleakage of silver ions was measured by exposure to laser ablation with an inductively connected plasma mass spectrometer and by electron dispersive elemental analysis. Increasing etching times seemed to have a negligible effect on bond strength of Single Bond, producing an average value of ca 38 MPa. However, the silver uptake increased upon prolonged etching times. Short-term results suggest that overetching has no detrimental effect on bond strength values of Single Bond. However, increased silver uptake, depending on the etching time, raises concern about the long-term stability of the bond.

Effect of water content on the physical properties of model dentine primer and bonding resins.

OBJECTIVE: Primers and adhesives containing hydroxyethyl methacrylate (HEMA) are placed on moist dentine even though several studies indicate that water may interfere with the polymerization reaction. The purpose of this study was to evaluate the influence of increasing amounts of water on the physical properties of a model dentine primer resin (HEMA) and model dentine bonding resin (a mixture of HEMA and Bis-GMA). METHODS: Miniature (ca 10 x 0.5 mm (long x thick) hour-glass shaped and parallel-sided specimens were created by casting the monomer or comonomer mixtures into appropriately shaped moulds. The water content was either 0, 5, 9, 17 or 29 vol%. One hour after polymerization, half the specimens were subjected to physical testing under dry conditions. The other half were immersed in water for 24 h and then tested while wet. The ultimate tensile strength (UTS), modulus of elasticity (E), percent elongation at failure, and toughness were calculated. RESULTS: The properties of the dry-stored primer and bonding resins were not altered by water incorporation up to 9 vol%. Higher water content lowered the physical properties (P < 0.05). Immersion of primers polymers in water for 24 h significantly decreased their properties. Water immersion of the bonding resins was unaffected only for specimens containing 0 or 5 vol% water. CONCLUSIONS: The plasticizing effects of extrinsic water are far more important than the effects of intrinsic water in poly-HEMA resin. Hybrid layers composed primarily of poly-HEMA would be expected to be more elastic than those made with bifunctional, cross-linked polymer chains.

Anterior implant-supported reconstructions: a surgical challenge.

Reconstructive procedures are able to provide improved aesthetics for implant patients who present with anatomical limitations (e.g., vertical or horizontal tissue loss) in the anterior maxilla. Aesthetic results, however, are directly related to the ability of the treatment team to reconstruct the lost bone and soft tissue, place the implant into its proper tridimensional position in the patient's arch, and use precise restorative techniques. This article presents comprehensive treatment steps for the utilization of single-unit and multiple-unit implant-supported restorations in the anterior maxilla.

Anterior implant-supported reconstructions: a prosthetic challenge.

Recent investigations have demonstrated that the successful utilization of anterior implant-supported restorations in the maxilla is dependent upon the satisfaction of numerous surgical and prosthodontic criteria. Conservative treatment alternatives that use a provisionalization phase can provide clinical benefits for patients with partial edentulism by guiding tissue maturation following completion of a meticulous surgical procedure. This article demonstrates a series of prosthetic considerations that guide contemporary aesthetic restorations, and highlights the underlying surgical factors related to this treatment.

Perfusing dentine with horse serum or physiologic saline: its effect on adhesion of dentine bonding agents.

Freshly prepared dentine specimens of human teeth were perfused with either horse serum or physiologic saline. After application of AllBond2, ART Bond, Syntac or an experimental dentine bonding agent called P-Bond, a composite cylinder was added and cured at the same time. After 1500 thermal cycles with constant imitation of intrapulpal pressure, the shear bond strengths were measured. Resulting shear bond strength values were analysed with Students t-test or Mann-Whitney Test. The values for AllBond2 were not significantly different. The values for ART Bond (P < 0.05) and for Syntac (P < 0.05) were significantly higher if the dentine was perfused with horse serum. For P-Bond (P < 0.001) the values were significantly higher if the dentine was perfused with physiologic saline. According to these results it does not seem to be appropriate to take a clear decision as to which of the two perfusing media investigated might be more suitable to imitate in vivo conditions.

Evaluation of the interface between one-bottle bonding agents and dentin by cryopreparation and low-temperature scanning electron microscopy (LTSEM). A pilot study on perfused dentinal samples.

OBJECTIVES: Dentin bonding samples are generally observed in the high vacuum chamber of an electron microscope only after completion of the bonding procedure fixation, dehydration and drying of the specimens. The purpose of this study was to observe the effect of each step in the application of various one-bottle dentin bonding agents (DBA) using cryopreparation followed by low-temperature scanning electron microscopy (LTSEM). METHODS: Prime&Bond 2.1 (P&B 2.1), Coltène Experimental (Exp.) and Syntac Single Component (Syntac SC) were applied onto perfused dentin of extracted, human third permanent molar teeth. After acid-etching, rinsing and drying, and following the application of the respective resins, the teeth were fractured at random and plunge-frozen in liquid nitrogen before examination under LTSEM. As this method preserves the state of the treated surface at the moment when it is frozen, each step of the application of the DBA can be observed as if it were a 'real-time' procedure. RESULTS: Acid-etching the dentin resulted in the removal of the smear layer for all materials tested. Those one-bottle DBAs which recommend the application of two consecutive resin layers (P&B 2.1 and Syntac SC) showed incomplete saturation of the dentinal surface after application of the first layer. With Syntac SC the incomplete saturation was more pronounced than with P&B 2.1. The use of Exp. resulted in a much more homogeneous coverage of the dentin despite only one layer of resin having been applied. CONCLUSION: It is concluded that cryo-preparation followed by LTSEM appears to be a method which allows each stage of the application of DBA to be evaluated.