Bioimpedance-Guided Hydration for the Prevention of Contrast-Induced Kidney Injury: The HYDRA Study

Background

Intravascular volume expansion plays a major role in the prevention of contrast-induced acute kidney injury (CI-AKI). Recommended standard amounts of fluid infusion before procedures do not produce homogeneous responses in subjects with different initial hydration status.

A Digital Approach to Retrofitting a Post and Core Restoration to an Existing Crown

One problem that may arise in full‐coverage restorations is clinical crown fracture. Fracture of an endodontically treated and crowned tooth in the esthetic zone may be embarrassing to both the patient and clinician. If a completely sound margin and at least 2 mm of coronal structure remain, a fractured tooth may possibly be retreated by a repair. Several methods have been introduced to reproduce the original contour of the tooth for retrofitting an existing crown. If an existing crown is used as a template, excessive core material may remain over the margin, as loading the proper amount of core material is difficult, and making vent holes on the existing crown is not feasible. This article presents a repair technique to reuse an existing crown with computer‐aided design and computer‐aided manufacturing (CAD/CAM) technology. By using a milled poly(methylmethacrylate) matrix, the mentioned limitations are eliminated, and the original contour of the tooth can be effectively restored with minimal intervention. As an existing crown is reused, the issues of additional time and cost for repreparation, reimpression, and new crown are eliminated.     

Colour stainability of indirect CAD–CAM processed composites vs. conventionally laboratory processed composites after immersion in staining solutions

Objectives

The aim of this study was to determine, by using a spectrophotometer device, the colour stainability of two indirect CAD/CAM processed composites in comparison with two conventionally laboratory-processed composites after being immersed 4 weeks in staining solutions such as coffee, black tea and red wine, using distilled water as control group.

Methods

Two indirect CAD/CAM composites (Lava Ultimate and Paradigm MZ100) and two conventionally laboratory-processed composites (SR Adoro and Premise Indirect) of shade A2 were selected (160 disc samples). Colour stainability was measured after 4 weeks of immersion in three staining solutions (black tea, coffee, red wine) and distilled water. Specimen's colour was measured each week by means of a spectrophotometer (CIE L*a*b* system). Statistical analysis was carried out performing repeated ANOVA measurements and Tukey's HSD test to evaluate differences in ΔE₀₀ measurements between groups; the interactions among composites, staining solutions and time duration were also evaluated.

Results

All materials showed significant discoloration (p < 0.01) when compared to control group. The highest ΔE₀₀ observed was with red wine, whereas black tea showed the lowest one. Indirect laboratory-processed resin composites showed the highest colour stability compared with CAD/CAM resin blocks.

Conclusions

CAD/CAM processed composites immersed in staining solutions showed lower colour stability when compared to conventionally laboratory-processed resin composites.

Clinical significance

The demand for CAD/CAM restorations has been increasing; however, colour stainability for such material has been insufficiently studied. Moreover, this has not been performed comparing CAD/CAM processed composites versus laboratory-processed indirect composites by immersing in staining solutions for long immersion periods.     

Comparative assessment of relapse and failure between CAD/CAM stainless steel and standard stainless steel fixed retainers in orthodontic retention patients:: A randomized controlled trial

ObjectivesTo compare relapse and failure rates of computer-aided design/computer-aided manufacturing (CAD/CAM) and standard fixed retainers.Materials and MethodsThis single-center, single-blinded, prospective randomized clinical trial included 46 patients who completed active orthodontic treatment and complied with retention visits. The patients were randomly assigned to three groups: CAD/CAM group with multistranded stainless steel wires (CAD/CAM, n = 16), Lab group with the same multistranded wires (lab, n = 16), and control group with stainless steel Ortho-FlexTech wires (traditional, n = 14). Intraoral scans were obtained at placement of fixed retainers (T1), 3-month visit (T2), and 6-month visit (T3) and measured for intercanine width and Little''s Irregularity Index. Failures were recorded.ResultsThe CAD/CAM group experienced less intercanine width decrease than the traditional group at 3 months (mean difference, 0.83 ± 0.16 mm; 95% confidence interval [CI], 0.44–1.22; P < .001) and 6 months (mean difference, 1.23 ± 0.40 mm; 95% CI, 0.19–2.27; P < .05). The CAD/CAM group experienced less increase in Little''s Irregularity Index compared with the lab group within 3 months (mean difference, 0.81 ± 0.27 mm; 95% CI, 0.12–1.49; P < .05). Failures from greatest to least were experienced by the lab group (43.8%), the CAD/CAM group (25%), and the traditional group (14.3%).ConclusionsWithin 6 months of bonding fixed retainers, CAD/CAM fixed retainers showed less relapse than lab-based and traditional chairside retainers and less failures than lab-based retainers.     

不同粘接剂间隙对CAD/CAM嵌体边缘适应性的影响

目的 探讨不同粘接剂间隙对CAD/CAM嵌体氧化锆粘接强度的影响.方法 选取因正畸需要拔除的第一前磨牙30颗作为本研究对象,依照设置粘接剂间隙参数不同分为10μm(A组)、30μm(B组)、50μm(C组)制作嵌体;用轻体型硅橡胶复制边缘间隙,体视显微镜测量边缘间隙的厚度,使用SPSS13.0软件包对数据进行分析.结果 所有瓷嵌体均可顺利就位,测量数据均小于120μm,A组肩台间隙明显低于B组及C组(P<0.05),且B组轴面显著低于C组(P<0.05).结论 在粘接间隙设定为10~50μm时,CEREC制作瓷嵌体均可取得满意效果.