Temporary threshold shift after noise exposure in hypobaric hypoxia at high altitude: results of the ADEMED expedition 2011.

OBJECTIVES: To evaluate whether there is an increased risk for noise-induced hearing loss at high altitude rsp. in hypobaric hypoxia. METHODS: Thirteen volunteers got standard audiometry at 125, 250, 500, 750, 1000, 1500, 2000, 3000, 4000, 6000, and 8000 Hz before and after 10 min of white noise at 90 dB. The system was calibrated for the respective altitude. Measurements were performed at Kathmandu (1400 m) and at Gorak Shep (5300 m) (Solo Khumbu/Nepal) after 10 days of acclimatization while on trek. Temporary threshold shift (TTS) was analyzed by descriptive statistics and by factor analysis. RESULTS: TTS is significantly more pronounced at high altitudes. Acclimatization does not provide any protection of the inner ear, although it increases arterial oxygen saturation. CONCLUSION: The thresholds beyond which noise protection is recommended (> 80 dB) or necessary (> 85 dB) are not sufficient at high altitudes. We suggest providing protective devices above an altitude of 1500 m ("ear threshold altitude") when noise level is higher than 75 dB and using them definitively above 80 dB. This takes the individual reaction on hypobaric hypoxia at high altitude into account.

The effect of zirconia and titanium surfaces on biofilm formation and on host-derived immunological parameters.

The aim of this study was to analyse the effect of zirconia and titanium surfaces on biofilm formation and host-derived parameters. Studies comparing zirconia and titanium surfaces were selected up to September 1, 2019. The outcome measures were surface roughness, contact angle, bacterial count, bacterial adherence, biofilm thickness, bacterial distribution, and specifically investigated biofilm and specific host-derived immunological parameters. Random-effects meta-analyses of in vitro and in vivo studies were conducted. A total of 39 studies were included for data extraction. In the systematic review data, 10 studies stated that zirconia accumulated less initial oral biofilm parameters, 16 investigations showed negligible inter-material differences, and only one study showed that zirconia attracted the most biofilm. However, in the meta-analysis, the bacterial coverage was found to be significantly superior for zirconia surfaces (P< 0.00001); the other outcome measures did not show any statistically significant differences between zirconia and titanium for the remaining parameters and the studies presented a substantial degree of heterogeneity. Overall, on the basis of the meta-analysis, the current data situation does not allow a clear preference for the use of zirconia or titanium.

Influence of bone density, screw size and surgical procedure on orthodontic mini-implant placement - part A: temperature development.

The aim of this in vitro study was to determine the influence of bone density, orthodontic mini-implant (OMI) size, and the surgical procedure on temperature increase during implant site osteotomy and placement. OMIs of different sizes (2.0×7, 2.3×7, 2.0×11, and 2.3×11mm) were placed in artificial bone blocks of different densities (D1-D4). Optionally, the drilling and insertion angle was 90° or 60° to the bone surface. A total of 640 OMIs were inserted, and predrilling was performed in 320 cases. All insertions were done without irrigation with an axial load of 20N, which resulted in 64 groups. Temperature measurements were performed during implant site preparation and placement using Type-K-thermocouples. Mean temperature increase differed for OMI osteotomy between 1.38°C and 8.75°C and placement between 3.8°C and 18.74°C, respectively. Critical thermal increase was especially reached during placement using long implants. Increasing bone density and implant size (diameter

Influence of bone density, screw size and surgical procedure on orthodontic mini-implant placement - part B: implant stability.

This in vitro study aimed to investigate the influence of bone density, implant size, and surgical procedure on the primary stability (PS) of orthodontic mini-implants (OMIs). In total, 640 OMIs of various sizes (2.0 × 7, 2.3 × 7, 2.0 × 11 and 2.3 × 11 mm) were inserted in the artificial bone of different densities (D1-D4). Placement was performed with an insertion angle of 90° or 60° to the bone surface and in 320 cases without predrilling, which resulted in 64 groups. PS was measured on the basis of implant stability quotient (ISQ) and insertion torque (IT). With regard to all possible influencing parameters, the mean PS differed between 39.20 and 60.00 (ISQ), and 10.00 and 39.00 Ncm (IT). The effect of OMI size and surgical procedure was dependent on bone quality. For example, implant size had less effect in high-density bone and was stronger with decreasing density. Overall, implant length had a greater influence than the diameter, and a high correlation was found among both PS measurement techniques. Therefore, a suitable choice of implant size and surgical protocol with regard to bone density can positively influence PS. In principle, ISQ and IT are suitable for measuring OMI stability.

Randomized in situ study on the efficacy of CO2 laser irradiation in increasing enamel erosion resistance.

OBJECTIVES: The aim of this double-blind, randomized in situ study was to evaluate the erosion-preventive effect of a specific set of CO2 laser parameters, associated or not with fluoride. METHODS: Two hundred forty bovine enamel blocks were prepared for individual palatal appliances (n = 6 samples/appliance). The study had four phases of 5 days each, with ten volunteers and the following treatments: CO2 laser irradiation (L), fluoride treatment (F), combined fluoride and laser treatment (FL), and no treatment, control (C). Laser irradiation was performed at 0.3 J/cm2 (5 µs/226 Hz/10.6 µm) and the fluoride gel contained AmF/NaF (12'500 ppm F-/pH = 4.8-6). For erosive demineralization, the appliances were immersed extra-orally in citric acid (0.05 M/20 min/pH = 2.3) twice daily. Analysis of enamel surface loss was done using a 3D-laser profilometer on 3 days. Additionally, fluoride uptake was quantified and scanning electron microscopies were done. Data were analyzed with repeated measures ANOVA and post hoc pairwise comparisons (α = 0.05). RESULTS: At all analyzing days, both laser groups caused the lowest means of enamel loss, which were also statistically significant lower than C (p < 0.05). At day 5, FL means ± SD (33.6 ± 12.6 µm) were even significantly lower than all other groups (C 67.8 ± 15.4 µm; F 57.5 ± 20.3 µm; L 46.8 ± 14.5 µm). Significantly increased enamel fluoride uptake was observed for both fluoride-containing groups (p < 0.05) at day 1. CONCLUSION: Compared to the control, the CO2 laser irradiation with a specific set of laser parameters (0.3 J/cm2/5 µs/226 Hz) either alone or in combination with a fluoride gel (AmF/NaF) could significantly decrease enamel erosive loss up to 5 days in situ. CLINICAL RELEVANCE: Combined CO2 laser-fluoride treatment has a significant anti-erosive effect.

Characterization of blunt chest trauma in a long-term porcine model of severe multiple trauma.

Chest trauma has a significant relevance on outcome after severe trauma. Clinically, impaired lung function typically occurs within 72 hours after trauma. However, the underlying pathophysiological mechanisms are still not fully elucidated. Therefore, we aimed to establish an experimental long-term model to investigate physiological, morphologic and inflammatory changes, after severe trauma. Male pigs (sus scrofa) sustained severe trauma (including unilateral chest trauma, femur fracture, liver laceration and hemorrhagic shock). Additionally, non-injured animals served as sham controls. Chest trauma resulted in severe lung damage on both CT and histological analyses. Furthermore, severe inflammation with a systemic increase of IL-6 (p = 0.0305) and a local increase of IL-8 in BAL (p = 0.0009) was observed. The pO2/FiO2 ratio in trauma animals decreased over the observation period (p < 0.0001) but not in the sham group (p = 0.2967). Electrical Impedance Tomography (EIT) revealed differences between the traumatized and healthy lung (p < 0.0001). In conclusion, a clinically relevant, long-term model of blunt chest trauma with concomitant injuries has been developed. This reproducible model allows to examine local and systemic consequences of trauma and is valid for investigation of potential diagnostic or therapeutic options. In this context, EIT might represent a radiation-free method for bedside diagnostics.

Effects on primary stability of three different techniques for implant site preparation in synthetic bone models of different densities.

Preparation of implant sites affect the primary stability of implants that is necessary for osseointegration. We have investigated the effect on the primary stability of implants of three techniques used to prepare the site for implants in synthetic bone models of different densities. A total of 540 implants of varying diameters (3.3 (narrow), 4.1 (standard), and 4.8 (wide) mm) and lengths (8 or 12mm) were inserted into three artificial bone blocks (the density of which decreased from D2, D3, to D4), and we compared conventional, fully-guided, and condensing preparation of the site. After insertion, primary stability was measured using resonance frequency analysis. There were significant differences between conventional and condensing procedures (p <0.0001 in all cases) and between fully-guided and condensing procedures (p<0.01 in all cases), but there were no differences between fully-guided and conventional procedures when short implants were used, with a standard or wide diameter in low-density bone blocks (D3 and D4). In low-density bone blocks (D3 and D4) wide implants (4.8mm) compared with narrow (3.3mm) resulted in significantly better primary stability (p<0.0001 in all cases). Fully-guided preparation of the implant site is associated with increased primary stability, but is not an alternative to bone condensing. Use of longer or wider implants can increase primary stability, but the effect is less pronounced after bone condensing.

Thermal evaluation by infrared measurement of implant site preparation between single and gradual drilling in artificial bone blocks of different densities.

The aim of this study was to investigate the influence of bone density and drilling protocol on heat generation during implant bed preparation. Ten single and 10 gradual implant sites with diameters of 2.8, 3.5, and 4.2mm were prepared in four artificial bone blocks (density types I-IV; D1-D4). Drilling was done at constant speed (1500rpm) and with external irrigation (50ml/min); vertical speed was set at 2mm/s. An infrared camera was used for temperature measurements. Significantly higher temperatures for single drilling were found between 2.8-mm drills in D1 (P=0.0014) and D4 (P<0.0001) and between 3.5-mm drills in D3 (P=0.0087) and D4 (P<0.0001), as well as between 4.2-mm drills in D1 (P<0.0001) and D4 (P=0.0014). Low bone density led to a thermal decrease after single drilling and a thermal increase after gradual drilling. Burs with a large diameter always showed a higher temperature generation. In comparisons between 2.8- and 4.2-mm diameters for both single and gradual drills, significant differences (P<0.001) were noted for bone types II, III, and IV. Single drilling could generate more heat than traditional sequential drilling, and bone density, as well as drill diameter, influenced thermal increases. Particularly in lower-density bone, conventional sequential drilling seems to raise the temperature less.

Compensating for poor primary implant stability in different bone densities by varying implant geometry: a laboratory study.

The aim of this study was to determine the influence of implant diameter and length on primary stability in artificial bone blocks. In total, 240 implants of various diameters (Ø 3.3, 4.1, and 4.8mm) and lengths (8 and 12 mm) were inserted in four artificial bone blocks of different densities (D1-D4). The primary stability for each bone block density was measured and compared with the primary stability of a narrow and short implant (Ø 3.3mm, length 8mm) in the next higher density block. Analysis was done by three-way ANOVA, and mean differences were determined with the 95% confidence interval. Levels of primary stability achieved by choosing the next higher diameter or length were not comparable to those of the next level of block density. However, equivalent values could be achieved by selecting the largest diameter for short and long implants in the lowest block density D4, as well as for long implants in bone type D2. The diameter of an implant has greater influence on primary stability than length. In particular, in the case of poor bone quality, a variation of implant geometry can lead to significant improvement in primary stability.

[Evaluation of 12 pilot projects to improve outpatient palliative care]. / Evaluation von 12 Pilotprojekten zur Verbesserung der ambulanten Palliativversorgung.

BACKGROUND: With a priority programme the German Cancer Aid supported the development of quality-assured outpatient palliative care to cover the whole country. The 12 regional pilot projects funded with the aim to improve outpatient palliative care in different models and different frameworks were concurrently monitored and evaluated. METHODS: The supported projects, starting and ending individually, documented all patients who were cared for using HOPE (Hospice and palliative care evaluation) and MIDOS (Minimal documentation system for palliative patients). Total data were analyzed for 3239 patients decriptively. In addition to the quantitative data the experiences of the projects were recorded in a number of workshops (2008, 2009, 2010, and 2012). In particular, the experiences reported in the final meeting in July 2012 were considered for this article as well as the final reports for the German Cancer Aid. RESULTS: In the quantitative evaluation 85.6% of 3239 palliative care patients had a cancer diagnosis. In all model projects the goal of a network with close cooperation of primary providers, social support, and outpatient and inpatient specialist services has been achieved. For all projects, the initial financing of the German Cancer Aid was extremely important, because contracts with health insurance funds were negotiated slowly, and could then be built on the experiences with the projects. CONCLUSION: The participants of the project-completion meeting emphasized the need to carry out a market analysis before starting palliative care organizations considering the different regional structures and target groups of patients. Education, training and continuing education programs contribute significantly to the network. A reliably funded coordination center/case management across all institutions is extremely important.

Prognostic role of microRNA polymorphisms in advanced gastric cancer: a translational study of the Arbeitsgemeinschaft Internistische Onkologie (AIO).

BACKGROUND: To determine the prognostic role of selected microRNA (miRNA) polymorphisms in advanced gastric cancer (AGC). PATIENTS AND METHODS: Six hundred and seventy-four AGC patients received 5-fluorouracil (F), leucovorin (L), oxaliplatin (O) or FL + cisplatin (P) or additional docetaxel (T) to FLO (FLOT) within four clinical trials. Polymorphisms of mir-26a1 (rs7372209), mir-27a (rs895819), mir-100 (rs1834306), mir-146a (rs2910164), mir-196-a2 (rs11614913), mir-219-1 (rs107822) and mir-423 (rs6505162) were genotyped. Variable selection for the final multivariate model (n = 487) was based on univariate and multivariate Cox-regression analyses with a cut-off P-value of ≤ 20%. RESULTS: Genetic factors significantly associated with overall survival (OS) were rs7372209 (mir-26a1) variant genotypes (hazard ratio, HR 1.307 [95% confidence interval (CI) 1.031-1.656], P = 0.0272), rs895819 (mir-27a) variant genotypes (HR 1.304 [95% CI 1.031-1.650], P = 0.0270) and rs11614913 (mir-196a2) variant genotypes (HR 0.791 [95% CI 0.625-1.000], P = 0.0497). Clinical factors with significant impact on OS were Eastern Cooperative Oncology Group (ECOG) 2 performance status (HR 1.880 [95% CI 1.254-2.820], P = 0.0023), curative surgery of advanced disease (HR 0.235 [95% CI 0.123-0.449], P < 0.0001) and addition of docetaxel in locally AGC patients (HR 0.348 [95% CI 0.145-0.838], P = 0.0301). Combined analyses revealed an improved OS in patients without any unfavourable genotype of 18 months compared with 14, 12 and 10 months in patients with 1, 2 and 3 unfavourable genotypes, respectively (P = 0.0257). CONCLUSIONS: These data suggest a significant impact of selected miRNA polymorphisms on prognosis in AGC.

Carbon dioxide-contrasted computed tomography angiography: high pitch protocols and adapted injection parameters improve imaging quality.

PURPOSE: To systematically investigate the impact of image acquisition and contrast injection parameters for CO2-enhanced CT angiography (CTA) of the aorto-iliac and peripheral arteries in a pig model using commercially available equipment. The aim was to establish an imaging protocol that is ready for use in human subjects. MATERIALS AND METHODS: Three domestic swine underwent CO2-CTA with varying injection parameters: pitch (1.0, 3.0), injection pressure (0.7 bar, 1.0 bar, 1.3 bar) and scan delay (2 s, 4 s, 6 s). Objective (vessel diameter) and subjective (image quality) parameters and applied radiation doses were systematically evaluated. To ensure clinical applicability of the setting, only approved catheters/injectors and standard injection parameters were evaluated. RESULTS: The image quality scores were superior and the vessel diameter was larger with high pitch in comparison to standard pitch (diameters: 4.7 ± 2.0 mm vs. 3.6 ± 2.1 mm, p = 0.0040, scores: 2.6 ± 1.1 vs. 2.0 ± 1.1, p = 0.0038). High injection pressure (1.3 bar) improved the image quality as assessed by subjective and objective ratings (diameters: 3.6 ± 2.0 mm, 4.0 ± 2.1 mm and 4.6 ± 2.1 mm, for 0.7, 1.0 and 1.3 bar, p-values ≤ 0.0052, scores: 1.9 ± 1.1, 2.3 ± 1.1 and 2.7 ± 1.2, p-values ≤ 0.0017), the same was observed for a shorter injection delay (diameters: 3.5 ± 2.0 mm, 4.2 ± 2.1 mm and 4.8 ± 2.1 mm, for 6 s, 4 s, and 2 s, p ≤ 0.0022, scores: 1.9 ± 1.1, 2.3 ± 1.1 and 2.7 ± 1.1, p-values ≤ 0.0013). The dose length products were 239 ± 47 mGycm (high pitch) and 565 ± 63 mGycm (standard pitch, p-values < 0.0001). CONCLUSION: A higher pitch, shorter delay and higher injection pressure improve image quality in CO2-enhanced CTA. Since commercially available, clinically approved equipment was used. The protocol is now ready for use in human subjects.

Thermoregulation of Premature Infants during and after Skin-to-Skin Care.

OBJECTIVE: Providing normothermia is an important issue in daily routine care of premature neonates. We recently found with infrared thermography (IRT) a drop in skin temperature of premature babies after they were positioned from skin-to-skin care (SSC) back into the incubator. Since this did not disappear within 10 min, we wanted to find out how long it takes until the baby has fully warmed up after SSC and if the IRT measurements correlate with conventional rectal temperature? STUDY DESIGN: A prospective observational study was undertaken with 5 premature infants [3 male, median gestational age 28 weeks (25-29), median age at study 34 d (28-52), median birth weight 898 g (400-1095), median weight at study 1263 g (790-1465)], temperature was determined with IRT (leg, back, arm, head, upper abdomen; diameter 1 cm, scale 0.00°C), comparison with 2 conventional sensors and rectal temperature. Temperatures were recorded every 2 min and displayed for 4 time points, namely at the beginning and the end of skin-to-skin care (SSC1, SSC2), as well as at the beginning and the end of a subsequent 60 min incubator period (I). RESULTS: A significant rise during SSC occurred while the cooling after SSC persisted during the complete incubator measurement time (I; p<0.05). Rectal temperature remained stable through the whole measuring period. CONCLUSION: While SSC in our setting led to an increase in temperature, the lack of compensation of peripheral heat loss in the incubator after 60 min may express an inadequate peripheral regulation of body temperature. This should be taken into account before routine care after SSC.

Diagnostic value of an interleukin-6 bedside test in term and preterm neonates at the time of clinical suspicion of early- and late-onset bacterial infection.

BACKGROUND: For quick detection or exclusion of neonatal early-onset bacterial infection (EOBI) or late-onset bacterial infection (LOBI), interleukin (IL)-6 is used. Its clinical use is sometimes limited due to prolonged recall times. Therefore, an IL-6 bedside test was established. OBJECTIVE: To compare the diagnostic value of plasma IL-6 and an IL-6 bedside test at the time of clinical suspicion in the course of EOBI and LOBI. METHODS: Eighteen term (mean gestational age 40.2 weeks, SD 1.3) and 88 preterm (mean gestational age 30.1 weeks, SD 4.2) neonates with clinical and serological signs of bacterial infection were analysed. Eight had an EOBI, and 24 had a LOBI, of whom 13 were blood culture positive. Twelve term and 62 preterm neonates with risk factors but without proven EOBI/LOBI served as a non-infected group. RESULTS: At the time of clinical suspicion, the sensitivity of the IL-6 bedside test in comparison to plasma IL-6 was 69 versus 75% (p = 0.7744, McNemar's test), and specificity was 77 versus 81% (p = 0.6476, McNemar's test; cutoff level 50 ng/l). For LOBI, both the sensitivity (75%) and specificity (82%) of the bedside test exceeded values calculated for EOBI (sensitivity 50%, specificity 75%). CONCLUSION: No significant difference between the bedside and established plasma IL-6 test was detected for LOBI. For detection of EOBI, the bedside test was not sensitive enough. Larger studies are needed to verify our findings before IL-6 bedside tests can be recommended routinely.

Influence of selection bias on the test decision. A simulation study.

BACKGROUND: Selection bias arises in clinical trials by reason of selective assignment of patients to treatment groups. Even in randomized clinical trials with allocation concealment this phenomenon can occur if future assignments can be predicted due to knowledge of former allocations. OBJECTIVES: Considering unmasked randomized clinical trials with allocation concealment the impact of selection bias on type I error rate under permuted block randomization is investigated. We aimed to extend the existing research into this topic by including practical assumptions concerning misclassification of patient characteristics to get an estimate of type I error close to clinical routine. To establish an upper bound for the type I error rate different biasing strategies of the investigator are compared first. In addition, the aspect of patient availability is considered. METHODS: To evaluate the influence of selection bias on type I error rate under several practical situations, different block sizes, selection effects, biasing strategies and success rates of patient classification were simulated using SAS. RESULTS: Type I error rate exceeds 5 percent significance level; it reaches values up to 21 percent. More cautious biasing strategies and misclassification of patient characteristics may diminish but cannot eliminate selection bias. The number of screened patients is about three times larger than the needed number for the trial. CONCLUSIONS: Even in unmasked randomized clinical trials using permuted block randomization with allocation concealment the influence of selection bias must not be disregarded evaluating the test decision. It should be incorporated when designing and reporting a clinical trial.

Quality indicators for the development and didactics of ultrasound courses in continuing medical education.

PURPOSE: Based on evaluation data from participant feedback, a concept was to be developed for introductory abdominal ultrasound courses lasting several days. This approach was to be developed incrementally with the intent of maximizing the learning effect per time. MATERIALS AND METHODS: This concept has been modified annually over several years based on the findings of educational research and the scores on final examinations in OSCE format. It has been modified with the aid of detailed questionnaires completed by approximately 2000 participating physicians and has thus undergone incremental optimization. RESULTS: Analysis of the most recent 1005 questionnaires has shown that participants recommend a modular course design with only brief lectures on theory (average optimal duration of 20 min., SD 9.6 min.). These should alternate with longer practical "hands-on" ultrasound exercises (60 - 90 min., accounting for at least 50 - 60 % of the course time), consolidating drawing exercises, and breaks. 51 % of the physicians specified 5 participants as the ideal group size for practical exercises, while 43 % specified only 4. The discussion presents 10 specific quality indicators for efficient ultrasound courses. It elucidates the feasibility and logistical prerequisites of this model, and compares it with other basic course concepts. Furthermore, this article presents a model for an evaluation covering the course concept and tutors as well as discussing a training program for tutors including a cost analysis. CONCLUSION: In summary, the participants estimate the course design to represent a mature concept that has demonstrated its feasibility and broad acceptance among physicians in CME.

[Accompanying evalution of funded projects in palliative medicine of the German Cancer Aid]. / Begleitevaluation des Förderschwerpunkts Palliativmedizin der Deutschen Krebshilfe.

INTRODUCTION: The German Cancer Aid funded 12 regional projects which developed different models of palliative home care. The realization of the projects were concurrently monitored and evaluated. MATERIAL AND METHODS: The funded projects were asked to document all patients who were cared for beginning in January 2009 using HOPE (Hospice and palliative survey), MIDOS (Minimal documentation system for palliative patients) and the Barthel index. Documentation was mandatory at the beginning and the end of care as well as when patients changed settings, for example when patients were transferred from a palliative care unit to a palliative home care service. Additionally the projects were visited by an independent observer. RESULTS: Overall the 12 projects documented 2,663 patients. Analysis revealed differences between the projects mainly concerning target groups and interventions. DISCUSSION: The results of this evaluation can support the discussion about the development of palliative home care in Germany with particular focus on possible interrelations between structures, target groups and possible outcomes of care.

Prevention of toothbrushing abrasion of acid-softened enamel by CO(2) laser irradiation.

OBJECTIVE: The aim of the present study was to evaluate the effect of CO(2) laser irradiation (10.6µm) at 0.3J/cm(2) (0.5µs; 226Hz) on the resistance of softened enamel to toothbrushing abrasion, in vitro. METHODS: Sixty human enamel samples were obtained, polished with silicon carbide papers and randomly divided into five groups (n=12), receiving 5 different surface treatments: laser irradiation (L), fluoride (AmF/NaF gel) application (F), laser prior to fluoride (LF), fluoride prior to laser (FL), non-treated control (C). After surface treatment they were submitted to a 25-day erosive-abrasive cycle in 100ml sprite light (90s) and brushed twice daily with an electric toothbrush. Between the demineralization periods samples were immersed in supersaturated mineral solution. At the end of the experiments enamel surface loss was determined using a contact profilometer and morphological analysis was performed using scanning electron microscopy (SEM). For SEM analysis of demineralization pattern, cross-sectional cuts of cycled samples were prepared. The data were statistically analysed by one-way ANOVA model with subsequent pairwise comparison of treatments. RESULTS: Abrasive surface loss was significantly lower in all laser groups compared to both control and fluoride groups (p<0.0001 in all cases). Amongst the laser groups no significant difference was observed. Softened enamel layer underneath lesions was less pronounced in laser-irradiated samples. CONCLUSION: Irradiation of dental enamel with a CO(2) laser at 0.3J/cm(2) (5µs, 226Hz) either alone or in combination with amine fluoride gel significantly decreases toothbrushing abrasion of softened-enamel, in vitro.

Outcome and mortality risk factors in long-term treated ICU patients: a retrospective analysis.

BACKGROUND: Little is known about the prognosis and outcome of critically ill patients with a prolonged length of stay (LOS). The aim of this study was to examine mortality and its risk factors in patients requiring intensive care therapy for more than 30 days. METHODS: A retrospective, single-center analysis of data collected in a surgical intensive care unit (ICU) of a university hospital in Germany from 2005 to 2007 was conducted. All demographic data and clinical variables were collected. A univariate analysis followed by multivariate regression was performed to detect the relevant risk factors for short and long-term mortality. RESULTS: Altogether, 10 737 patients were admitted to the ICU; 136 patients fulfilled the criteria for long-term treatment, 75% (N=102) of whom were discharged from ICU. The one-year survival rate was 61.8% (N=60). The most significant risk factors were pulmonary compromise with prolonged mechanical ventilation and infectious disorders leading to sepsis. However, sepsis was not a predictor of outcome. Weaning failure was present in 67.6% (N=92) at day 30 but was reduced to 37.5% of the cases (N=51) over the total course of the stay. Acute and long-term prognoses were determined by a successful weaning. CONCLUSION: Although the long-term treatment of critically ill patients requires significant effort, the outcome for this particular cohort was reasonably favorable. Prolonged mechanical ventilation and weaning are the factors that influence mortality independently of sepsis. Because reasonable improvements can be shown even after a prolonged LOS, further attention should be paid to weaning processes.

Rehardening of acid-softened enamel and prevention of enamel softening through CO2 laser irradiation.

OBJECTIVES: The aims of the present study were to investigate whether irradiation with a CO(2) laser could prevent surface softening (i) in sound and (ii) in already softened enamel in vitro. METHODS: 130 human enamel samples were obtained and polished with silicon carbide papers. They were divided into 10 groups (n = 13) receiving 5 different surface treatments: laser irradiation (L), fluoride (AmF/NaF gel) application (F), laser prior to fluoride (LF), fluoride prior to laser (FL), non-treated control (C); and submitted to 2 different procedures: half of the groups was acid-softened before surface treatment and the other half after. Immersion in 1% citric acid was the acid challenge. Surface microhardness (SMH) was measured at baseline, after softening and after treatment. Additionally, fluoride uptake in the enamel was quantified. The data were statistically analysed by two-way repeated measurements ANOVA and post hoc comparisons at 5% significance level. RESULTS: When softening was performed either before or after laser treatment, the L group presented at the end of the experiments SMH means that were not significantly different from baseline (p = 0.8432, p = 0.4620). Treatment after softening resulted for all laser groups in statistically significant increase in SMH means as compared to values after softening (p < 0.0001). Enamel fluoride uptake was significantly higher for combined laser-fluoride treatment than in control (p<0.0001). CONCLUSION: Irradiation of dental enamel with a CO(2) laser at 0.3J/cm(2) (5 µs, 226 Hz) not only significantly decreased erosive mineral loss (97%) but also rehardened previously softened enamel in vitro.