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Selected AbstractsMinimally Invasive Flapless Implant Surgery: A Prospective Multicenter StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2005ODhc, William Becker DDS ABSTRACT Background: Placement of implants with a minimally invasive flapless approach has the potential to minimize crestal bone loss, soft tissue inflammation, and probing depth adjacent to implants and to minimize surgical time. Purpose: The aim of this multicenter study was to evaluate implant placement using a minimally invasive one-stage flapless technique up to 2 years. Materials and Methods: Fifty-seven patients ranging in age from 24 to 86 years were recruited from three clinical centers (Tucson, AZ, USA; Tel Aviv, Israel; Göteborg, Sweden). Seventy-nine implants were placed. A small, sharp-tipped guiding drill was used to create a precise, minimally invasive initial penetration through the mucosa and into bone (Nobel Biocare, Yorba, Linda, CA, USA). Implants were placed according to the manufacturer's instructions, with minimal countersinking. The parameters evaluated were total surgical time, implant survival, bone quality and quantity, implant position by tooth type, depth from mucosal margin to bone crest, implant length, probing depth, inflammation, and crestal bone changes. At 2 years, for 79 implants placed in 57 patients, the cumulative success rate using a minimally invasive flapless method was 98.7%, indicating the loss of 1 implant. Changes in crestal bone for 77 baseline and follow-up measurements were insignificant (radiograph 1: mean 0.7 mm, SD 0.5 mm, range 2.8 mm, minimum 0.2 mm, maximum 3.0 mm; radiograph 2: mean 0.8 mm, SD 0.5 mm, range 3.4 mm, minimum 0.12 mm, maximum 3.5 mm). Using descriptive statistics for 78 patients (one implant lost), mean changes for probing depth and inflammation were clinically insignificant. The average time for implant placement was 28 minutes (minimum 10 minutes, maximum 60 minutes, SD 13.1 minutes). Average depth from mucosal margin to bone was 3.3 mm (SD 0.7 mm, minimum 2 mm, maximum 5 mm, range 3 mm). Thirty-two implants were placed in maxillae and 47 in mandibles. Conclusions: The results of this study demonstrate that following diagnostic treatment planning criteria, flapless surgery using a minimally invasive technique is a predictable procedure. The benefits of this procedure are lessened surgical time; minimal changes in crestal bone levels, probing depth, and inflammation; perceived minimized bleeding; and lessened postoperative discomfort. [source] The micro-topography of the wetlands of the Okavango Delta, BotswanaEARTH SURFACE PROCESSES AND LANDFORMS, Issue 1 2005T. Gumbricht Abstract The surface of the 40 000 km2 Okavango alluvial fan is remarkably smooth, and almost everywhere lies within two to three metres of a perfectly smooth theoretical surface. Deviations from this perfect surface give rise to islands in the Okavango wetlands. This micro-topography was mapped by assigning empirical elevations to remotely sensed vegetation community classes, based on the observation that vegetation is very sensitive to small, local differences in elevation. Even though empirical, the method produces fairly accurate results. The technique allows estimation of depths of inundation and therefore will be applicable even when high resolution radar altimetry becomes available. The micro-topography has arisen as a result of clastic sedimentation in distributary channels, which produces local relief of less than two metres, and more importantly as a result of chemical precipitation in island soils, which produces similar local relief. The micro-topography is, therefore, an expression of the non-random sedimentation taking place on the fan. Volume calculations of islands extracted from the micro-topography, combined with estimates of current sediment in,ux, suggest that the land surface of the wetland may only be a few tens of thousands of years old. Constant switching of water distribution, driven by local aggradation, has distributed sediment widely. Mass balance calculations suggest that over a period of c. 150 000 years all of the fan would at one time or other have been inundated, and thus subject to sedimentation. Coalescing of islands over time results in net aggradation of the fan surface. The amount of vertical aggradation on islands and in channels is restricted by the water depth. Restricted vertical relief, in turn, maximizes the distribution of water, limiting its average depth. Aggradation in the permanent swamps occurs predominantly by clastic sedimentation. Rates of aggradation here are very similar to those in the seasonal swamps, maintaining the overall gradient, possibly because of the operation of a feedback loop between the two. The limited amount of local aggradation arising from both clastic and chemical sedimentation, combined with constant changes in water distribution, has resulted in a near-perfect conical surface over the fan. In addition to providing information on sedimentary processes, the micro-topography has several useful hydrological applications. Copyright © 2004 John Wiley & Sons, Ltd. [source] The effect of ultrasonically activated irrigation on reduction of Enterococcus faecalis in experimentally infected root canalsINTERNATIONAL ENDODONTIC JOURNAL, Issue 11 2010A. J. Harrison Harrison AJ, Chivatxaranukul P, Parashos P, Messer HH. The effect of ultrasonically activated irrigation on reduction of Enterococcus faecalis in experimentally infected root canals. International Endodontic Journal, 43, 968,977, 2010. Abstract Aim, To investigate the ability of an ultrasonically activated irrigating system to eliminate bacteria from the canal wall and dentinal tubules of extracted teeth. Methodology, One hundred and thirty roots of intact human teeth were inoculated with Enterococcus faecalis for 4 weeks. The straight roots were randomly allocated to a baseline group (n = 25) or subjected to routine cleaning and shaping procedures (n = 105). Two sub-groups of prepared canals were then additionally exposed either to ultrasonic irrigation with 1% sodium hypochlorite (NaOCl) for 1 min (n = 35) or to 1 week of intracanal medication with calcium hydroxide [Ca(OH)2] (n = 35). All roots were processed for light microscopy (Brown and Brenn stain) (n = 28) or scanning electron microscopy (n = 7). Triplicate histological sections from each of the apical, middle and coronal thirds were scored for bacterial presence using pre-defined criteria. Results, Baseline bacterial penetration resulted in an average depth of tubule invasion of 151 ,m. Routine canal preparation failed to eliminate bacteria consistently from either the canal wall or within tubules. Ultrasonic irrigation and medication with Ca(OH)2 consistently eliminated bacteria from the canal wall (P < 0.001) compared with baseline and routine treatment, and more frequently from dentinal tubules than routine canal preparation alone (P < 0.01). Ultrasonic irrigation was as effective in bacterial reduction as 1 week of intracanal medication with Ca(OH)2, but neither led to complete bacterial elimination in all roots. Conclusions, Ultrasonically activated irrigation for 1 min with 1% NaOCl after canal preparation in straight root canals is potentially an effective supplementary step in microbial control. [source] Freezing of lakes on the Swiss plateau in the period 1901,2006INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 4 2008H. J. Hendricks Franssen Abstract Data of ice cover for deep Alpine lakes contain relevant climatological information since ice cover and winter temperature are closely related. For the first time, ice cover data from 11 lakes on the Swiss plateau have been collected and analysed for the period 1901,2006. The ice cover data used stem from systematic registration by individuals or groups (fishermen, an ice club and lake security service) and from several national, regional and local newspapers. It is found that in the past 40 years, and especially during the last two decades, ice cover on Swiss lakes was significantly reduced. This is in good agreement with the observed increase in the winter temperature in this period. The trend of reduced ice cover is more pronounced for lakes that freeze rarely than for the lakes that freeze more frequently. This agrees well with the stronger relative decrease in the probability to exceed the sum of negative degree days (NDD) needed for freezing the lakes that rarely freeze. The ice cover data are related with the temperature measurements such as the sum of NDD of nearby official meteorological stations by means of binomial logistic regression. The derived relationships estimate the probability of a complete ice cover on a lake as function of the sum of NDD. The sums of NDD needed are well related to the average depth of the lake (rNDD,Depth = 0.85). Diagnosing lake ice cover on the basis of the sum of NDD is much better than a prediction on the basis of a climatological freezing frequency. The variance of lake ice cover that cannot be explained by the sum of NDD is important for judging the uncertainty associated with climate reconstruction on the basis of data on lake ice cover. Copyright © 2007 Royal Meteorological Society [source] Variability of Organic Matter Processing in a Mediterranean Coastal LagoonINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 5-6 2004Margarita Menéndez Abstract The spatial variability of plant organic matter processing was studied experimentally in a shallow coastal lagoon (Tancada lagoon, average depth: 37 cm, area: 1.8 km2) in the Ebro River Delta (NE Spain). To determine the effect of hydrology and sediment characteristics on plant organic matter processing, leaves of Phragmites australis at the end of its vegetative cycle and whole plants of Ruppia cirrhosa(Petagna) Grande, just abscised, were enclosed in litter bags. Two different mesh sizes (100 ,m and 2 mm) were used to study the effect of macroinvertebrates on decomposition. The bags were placed in the water column and approximately 15 cm above the sediment at 6 different locations in the lagoon. The experiment was performed twice, in autumn-winter and spring-summer. The effect of macroinvertebrates on decomposition rate was not significant in Tancada lagoon. Breakdown rates showed spatial differences only in spring-summer. In the autumn-winter experiment, the effect of strong wind masked the effects of environmental variables and hydrology on decomposition rate. In the spring-summer experiment, characterised by high stability of the water column, dissolved inorganic nitrogen (DIN) concentration in the water column and organic matter in the sediment were the main factors determining the variability of organic matter processing. A positive relationship was calculated between P. australis decomposition rate and dissolved inorganic nitrogen in spring-summer (r2 = 0.92, p < 0.001). (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Microchannels created by sugar and metal microneedles: Characterization by microscopy, macromolecular flux and other techniquesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2010Guohua Li Abstract The objective of this study was to investigate the feasibility of using microneedle technology to enhance transcutaneous permeation of human immunoglobulin G (IgG) across hairless rat skin. Microchannels created by maltose and metal (DermaRollerÔ) microneedles were characterized by techniques such as methylene blue staining, histological examination, and calcein imaging. Methylene blue staining and histological sections of treated skin showed that maltose microneedles and DermaRollerÔ breached the skin barrier by creating microchannels in the skin with an average depth of ,150,µm, as imaged by confocal microscopy. Calcein imaging and pore permeability index values suggested the uniformity of the created pores in microneedle-treated skin. Transdermal studies with IgG indicated a flux rate of 45.96,ng/cm2/h, in vitro, and a Cmax of 7.27,ng/mL, in vivo, for maltose microneedles-treated skin while a flux rate of 353.17,ng/cm2/h, in vitro, and a Cmax of 9.33,ng/mL, in vivo, was achieved for DermaRollerÔ-treated skin. Transepidermal water loss measurements and methylene blue staining, in vivo, indicated the presence of microchannels for upto 24,h, when occluded. In conclusion, the microchannels created by maltose microneedles and DermaRollerÔ resulted in the percutaneous enhancement of a macromolecule, human IgG. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1931,1941, 2010 [source] | |||||||||||||