107 resultados para SOFT-START POLYMERIZATION

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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AIM To compare dentoskeletal and soft tissue treatment effects of two alternative Class II division 1 treatment modalities (maxillary first permanent molar extraction versus Herbst appliance). METHODS One-hundred-fifty-four Class II division 1 patients that had either been treated with extractions of the upper first molars and a lightwire multibracket (MB) appliance (n = 79; 38 girls, 41 boys) or non-extraction by means of a Herbst-MB appliance (n = 75; 35 girls, 40 boys). The groups were matched on age and sex. The average age at the start of treatment was 12.7 years for the extraction and for 13.0 years for the Herbst group. Pretreatment (T1) and posttreatment (T2) lateral cephalograms were retrospectively analyzed using a standard cephalometric analysis and the sagittal occlusal analysis according to Pancherz. RESULTS The SNA decrease was 1.10° (p = 0.001) more pronounced in the extraction group, the SNB angle increased 1.49° more in the Herbst group (p = 0.000). In the extraction group, a decrease in SNB angle (0.49°) was observed. The soft tissue profile convexity (N-Sn-Pog) decreased in both groups, which was 0.78° more (n. s.) pronounced in the Herbst group. The nasolabial angle increased significantly more (+ 2.33°, p = 0.025) in the extraction group. The mechanism of overjet correction in the extraction group was predominantly dental (65% dental and 35% skeletal changes), while in the Herbst group it was predominantly skeletal (58% skeletal and 42% dental changes) in origin. CONCLUSION Both treatment methods were successful and led to a correction of the Class II division 1 malocclusion. Whereas for upper first molar extraction treatment more dental and maxillary effects can be expected, in case of Herbst treatment skeletal and mandibular effects prevail.

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QUESTIONS UNDER STUDY: To determine the perception of primary care physicians regarding the risk of subsequent atherothrombotic events in patients with established cardiovascular (CV) disease, and to correlate this perception with documented antithrombotic therapy. METHODS: In a cross-sectional study of the general practice population in Switzerland, 381 primary care physicians screened 127 040 outpatients during 15 consecutive workdays in 2006. Perception of subsequent atherothrombotic events in patients with established CV disease was assessed using a tick box questionnaire allowing choices between low, moderate, high or very high risk. Logistic regression models were used to determine the relationship between risk perception and antithrombotic treatment. RESULTS: Overall, 13 057 patients (10.4%) were identified as having established CV disease and 48.8% of those were estimated to be at high to very high risk for subsequent atherothrombotic events. Estimated higher risk for subsequent atherothrombotic events was associated with a shift from aspirin monotherapy to clopidogrel, vitamin K antagonist or aspirin plus clopidogrel (p <0.001 for trend). Clopidogrel (12.7% vs 6.8%, p <0.001), vitamin K antagonist (24.5% vs 15.6%, p <0.001) or aspirin plus clopidogrel (10.2% vs 4.2%, p <0.001) were prescribed in patients estimated to be at high to very high risk more often than in those at low to moderate risk. CONCLUSIONS: Perception of primary care physicians regarding risk of subsequent atherothrombotic events varies in patients with CV disease, and as a result antithrombotic therapy is altered in patients with anticipated high to very high risk even though robust evidence and clear guidelines are lacking.

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PURPOSE: To evaluate the ratio of soft tissue to hard tissue in bilateral sagittal split setback osteotomy with rigid internal fixation or wire fixation. MATERIALS AND METHODS: A literature search was performed using PubMed, Medline, CINAHL, Web of Science, the Cochrane Library, and Google Scholar Beta. From the original 766 articles identified, 8 articles were included. Two articles were prospective and 6 retrospective. The follow-up period ranged from 1 year to 12.7 years for rigid internal fixation. Two articles on wire fixation were found to be appropriate for inclusion. RESULTS: The differences between short- and long-term ratios of the lower lip to lower incisors for bilateral sagittal split setback osteotomy with rigid internal fixation or wire fixation were quite small. The ratio was 1:1 in the long term and by trend slightly lower in the short term. No distinction was seen between the short- and long-term ratios for mentolabial fold. The ratio was found to be 1:1 for the mentolabial fold to point B. In the short term, the ratio of the soft tissue pogonion to the pogonion showed a 1:1 ratio, with a trend to be lower in the long term. The upper lip showed mainly protrusion, but the amount was highly variable. CONCLUSIONS: This systematic review shows that evidence-based conclusions on soft tissue changes are difficult to draw. This is mostly because of inherent problems of retrospective studies, inferior study designs, and the lack of standardized outcome measurements. Well-designed prospective studies with sufficient samples and excluding additional surgery, ie, genioplasty or maxillary surgery, are needed.

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PURPOSE: The purpose of the present systematic review was to evaluate the soft tissue/hard tissue ratio in bilateral sagittal split advancement osteotomy (BSSO) with rigid internal fixation (RIF) or wire fixation (WF). MATERIALS AND METHODS: The databases PubMed, Medline, CINAHL, Web of Science, Cochrane Library, and Google Scholar Beta were searched. From the original 711 articles identified, 12 were finally included. Only 3 studies were prospective and 9 were retrospective. The postoperative follow-up ranged from 3 months to 12.7 years for RIF and 6 months to 5 years for WF. RESULTS: The short- and long-term ratios for the lower lip to lower incisor for BSSO with RIF or WF were 50%. No difference between the short- and long-term ratios for the mentolabial-fold to point B and soft tissue pogonion to pogonion could be observed. It was a 1:1 ratio. One exception was seen for the long-term results of the soft tissue pogonion to pogonion in BSSO with RIF; they tended to be greater than a 1:1 ratio. The upper lip mainly showed retrusion but with high variability. CONCLUSIONS: Despite a large number of studies on the short- and long-term effects of mandibular advancement by BSSO, the results of the present systematic review have shown that evidence-based conclusions on soft tissue changes are still unknown. This is mostly because of the inherent problems of retrospective studies, inferior study designs, and the lack of standardized outcome measures. Well-designed prospective studies with sufficient sample sizes that have excluded patients undergoing additional surgery (ie, genioplasty or maxillary surgery) are needed.

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We propose a computationally efficient and biomechanically relevant soft-tissue simulation method for cranio-maxillofacial (CMF) surgery. A template-based facial muscle reconstruction was introduced to minimize the efforts on preparing a patient-specific model. A transversely isotropic mass-tensor model (MTM) was adopted to realize the effect of directional property of facial muscles in reasonable computation time. Additionally, sliding contact around teeth and mucosa was considered for more realistic simulation. Retrospective validation study with postoperative scan of a real patient showed that there were considerable improvements in simulation accuracy by incorporating template-based facial muscle anatomy and sliding contact.

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Objective: To compare the soft and hard tissue healing and remodeling around tissue-level implants with different neck configurations after at least 1 year of functional loading. Material and methods: Eighteen patients with multiple missing teeth in the posterior area received two implants inserted in the same sextant. One test (T) implant with a 1.8 mm turned neck and one control (C) implant with a 2.8 mm turned neck were randomly assigned. All implants were placed transmucosally to the same sink depth of approximately 1.8 mm. Peri-apical radiographs were obtained using the paralleling technique and digitized. Two investigators blinded to the implant type-evaluated soft and hard tissue conditions at baseline, 6 months and 1 year after loading. Results: The mean crestal bone levels and soft tissue parameters were not significantly different between T and C implants at all time points. However, T implants displayed significantly less crestal bone loss than C implants after 1 year. Moreover, a frequency analysis revealed a higher percentage (50%) of T implants with crestal bone levels 1–2 mm below the implant shoulder compared with C implants (5.6%) 1 year after loading. Conclusion: Implants with a reduced height turned neck of 1.8 mm may, indeed, lower the crestal bone resorption and hence, may maintain higher crestal bone levels than do implants with a 2.8 mm turned neck, when sunk to the same depth. Moreover, several factors other than the vertical positioning of the moderately rough SLA surface may influence crestal bone levels after 1 year of function.

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X-ray computed tomography (CT) using phase contrast can provide images with greatly enhanced soft-tissue contrast in comparison to conventional attenuation-based CT. We report on the first scan of a human specimen recorded with a phase-contrast CT system based on an x-ray grating interferometer and a conventional x-ray tube source. Feasibility and potential applications of preclinical and clinical phase-contrast CT are discussed.

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Critical limb ischemia due to peripheral arterial occlusive disease is associated with a severely increased morbidity and mortality. There is no effective pharmacological therapy available. Injection of autologous bone marrow-derived mononuclear cells (BM-MNC) is a promising therapeutic option in patients with critical limb ischemia, but double-blind, randomized trials are lacking.

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To investigate the surface hardness (Vickers hardness, HVN) of one light-curing flowable resin composite and five dual-curing resin cements after different polymerization procedures.

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Computerized soft-tissue simulation can provide unprecedented means for predicting facial outlook pre-operatively. Surgeons can virtually perform several surgical plans to have the best surgical results for their patients while considering corresponding soft-tissue outcome. It could be used as an interactive communication tool with their patients as well. There has been comprehensive amount of works for simulating soft-tissue for cranio-maxillofacial surgery. Although some of them have been realized as commercial products, none of them has been fully integrated into clinical practice due to the lack of accuracy and excessive amount of processing time. In this chapter, state-of-the-art and general workflow in facial soft-tissue simulation will be presented, along with an example of patient-specific facial soft-tissue simulation method.