Liver Trauma Management

Liver trauma is responsible for the majority of penetrating abdominal trauma and is the third most common injury caused by firearms. Presenting a 20% mortality rate, it is an organ with wide and complex vascularization, receiving blood from the hepatic veins and portal vein, as well as from the hepatic arteries. The diagnosis is not always simple in polytrauma patients and contains a wide range of exams such as computerized tomography and diagnostic peritoneal lavage. Treatment depends mostly on a few factors such as the patient’s hemodynamic stability, the degree of injury according to the AAST classification, the resources available, and the surgeon’s expertise. Considering these factors, minor lesions can be treated mostly with a conservative approach in hemodynamically stable patients. Embolization by arteriography has shown good results in major lesions in clinically stable patients as well. On the other hand, more complex lesions associated with hemodynamically unstable patients may indicate damage control surgery applying techniques such as temporary liver packing and clamping the pedicle to restore the hemodynamic status. This chapter aims to describe those techniques and their indications in liver trauma

Monomer conversion of pre-heated composite

The potential for maximizing conversion of room-temperature, photoactivated resin composite in the oral environment is limited. Pre- heating composite prior to light- curing is hypothesized to increase monomer conversion and reduce the duration of light exposure. Composite temperature was controlled at between 3 degrees C and 60 degrees C prior to exposure with a conventional quartz- tungsten-halogen curing unit: 5, 10, 20, or 40 sec. Monomer conversion was calculated from infrared spectra at 0 mm ( top) and 2- mm- deep surfaces 5 min after light initiation. A strong, positive correlation existed between temperature and monomer conversion: top r(2) = 0.999, 2 mm r(2) = 0.998. Conversion ranged from 31.6% ( 3 degrees C) to 67.3% ( 60 degrees C). The duration of light exposure, reduced by 50 to 75% with pre- heated composite, yielded the same or significantly higher conversion ( p = 0.001) than with control ( 22 degrees C, 20 sec). Both hypotheses were accepted: Pre- heating composite prior to photoactivation provides greater conversion requiring reduced light exposure than with room- temperature composite.84766366

Effect of composite temperature on in vitro intrapulpal temperature rise

Objectives. To measure in vitro intrapulpal temperature when placing and restoring with either room - temperature or pre-heated (54 and 60 degrees C) composite. Methods. A K-type thermocouple was placed in the pulpal chamber of an extracted, human bifurcated upper premolar which had a Class V preparation (I mm remaining dentin thickness) on the facial surface. Tooth roots were immersed in a thermostatically controlled water bath and perfused with water at 1.25 mu l/min to simulate physiological circulation in the pulp chamber. The thermocouple was connected to an analog-to- digital converter. The preparation was filled using composite either at room - temperature, or pre-heated to 54 or 60 degrees C with a commercial compule heater (Calset (TM)), using standard clinical procedures by one person while continuously monitoring intrapulpal temperature (n = 5). Temperature rise over baseline values were determined at various stages during the restoration process: composite placement, contouring, prior to light-curing, and immediately after light-curing (20 s, Optilux 501). At each measurement interval, intrapulpal temperature values were compared using ANOVA and the Tukey-Kramer post hoc test (alpha = 0.05). Results. Significant differences were found in intrapulpal temperature when comparing preheated and room-temperature composite treatments with respect to baseline among the stages of the restorative process. However, the extent of this increase with heated composite was only 0.8 degrees C. A 5 degrees C intrapulpal temperature rise was seen for all groups during photopolymerization. Significance. Use of pre-heated composite only mildly increased intrapulpal temperature values when compared to composite delivered at room- temperature in an in vitro test environment. The largest temperature change occurred with application of the curing light. (C) 2006 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.23101283128

Polymerization kinetics of pre-heated composite

Temperature affects the polymerization behavior of dimethacrylate- based materials. This study describes the influence of pre-polymerization temperature and exposure duration on polymerization kinetics of a commercial dental photo-activated composite at the top and at 2-mm depth. We used the temperature-controlled stage of a diamond-attenuated-total-reflectance unit to pre-set composite temperature between 3 and 60 degrees C. Composite was light-exposed by a conventional quartz-tungsten-halogen curing unit for 5, 10, 20, or 40 sec. Real-time conversion, maximum conversion rate ( Rp(max)), time to achieve Rpmax, and conversion at Rpmax were calculated from infrared spectra. Composite pre-warming enhanced maximal polymerization rate and overall monomer conversion (top significantly greater than 2 mm). Time when Rpmax occurred did not change with temperature, but occurred sooner at the top than at 2-mm depth. Conversion at Rp(max) increased with temperature, allowing more of the reaction to occur prior to vitrification than at room temperature.851384

In Vivo Temperature Measurement: Tooth Preparation and Restoration with Preheated Resin Composite

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Statement of the Problem: Composite preheating has shown to improve material physical properties in vitro, but no data exist on the use of this technique in vivo during placement. Purpose: The study aims to measure in vivo prepared tooth surface temperature during a restorative procedure using resin composite either at room temperature (23.6 degrees C) or preheated to 54.7 degrees C in a commercial compule heating device set to heat at 60 degrees C. Methods: Class I preparations (N = 3) were made on a patient requiring multiple posterior restorations. A probe containing two thermocouples was used to record temperature values at the tooth pulpal floor and 2 mm higher (top of the tooth preparation/restoration) after tooth preparation (prep), acid etching (etch), placement and curing of a bonding agent (BA), and during placement of composite used at room temperature (RT) or preheated in a commercial device (CalsetTM, AdDent Inc., Danbury, CT, USA) set to 60 degrees C. Data were compared with two-way analysis of variance, Tukey-Kramer post hoc test (alpha = 0.05). Results: No significant difference in pulpal floor temperature existed between prep (27.8 degrees +/- 1.3 degrees C) and etch (26.3 degrees +/- 1.3 degrees C), which were significantly lower than BA (30.5 degrees +/- 1.3 degrees C) (p = 0.0001). Immediate placement of preheated composite resulted in significantly higher pulpal floor (36.2 degrees +/- 1.9 degrees C) (p = 0.0025) and top composite temperatures (38.4 degrees +/- 2.2 degrees C) (p = 0.0034) than RT values (30.4 degrees +/- 2.2 degrees C and 29.6 degrees +/- 0.9 degrees C, respectively). Conclusions: In vivo use and placement of preheated resin composite resulted in temperature increase of 6 degrees to 8 degrees C than room temperature material. These values, however, were much lower than expected. CLINICAL SIGNIFICANCE Although having many potential benefits, composite preheating may not be as clinically effective in delivering resin of predetermined temperature at the time of cure as laboratory experiments would suggest. Despite only moderate composite temperature increase over use of room temperature material, preheating still provides advantages in terms of ease of handling and placement. (J Esthet Restor Dent 22:314-323, 2010).225314322Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Medical College of Georgia, School of DentistryCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPES [03/48031