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Effect of Milling Protocols on Trueness and Precision of Ceramic Crowns.


  • 影响因子:1.81
  • DOI:10.1111/jopr.13245
  • 作者列表:"Al Hamad KQ","Al-Rashdan RB","Al-Rashdan BA","Baba NZ
  • 发表时间:2021-02-01

PURPOSE:To investigate the effect of different milling protocols for different ceramic materials on the trueness and precision of milled ceramic crowns. MATERIALS AND METHODS:A definitive impression from a patient requiring a ceramic crown was used to fabricate forty glass ceramic crowns (VITABLOCS mark II, Vita Zahnfabrik) milled with wet, hard milling protocol, and 40 zirconia crowns (inCoris TZI, Dentsply, Sirona) milled with dry, soft milling protocol, using a 5-axis milling machine (inLab MC X5; Dentsply Sirona). Trueness and precision for different crown areas were evaluated with a 3D evaluation software (Geomagic Control X, 3D systems). Statistical analysis was performed between the 2 crown types with independent t-test, and analysis of variances followed by Bonferroni tests among crown areas for each crown. RESULTS:All areas of the glass ceramic crowns had higher trueness than the zirconia crown areas (p < 0.05). Crown areas of each crown type had significantly different trueness values (p < 0.001, F = 175.17 for glass crowns, p < 0.001, F = 35.04 for zirconia crowns). Glass crowns had 3.78 µm precision, while zirconia crowns had 4.12 µm precision, with a precision difference range between the 2 types of crowns from 0.32 µm for the inner surface to 6.5 µm for the marginal surface. CONCLUSIONS:Type of ceramic material and milling protocol affected trueness of the milled crown, with higher trueness for the hardmilled glass crowns than the soft milled zirconia crowns. Soft milled zirconia crowns were generally overmilled in comparison with the reference design and glass crowns. However, glass crowns exhibited more undermilling in thin and deep areas. The crown area affected trueness, with external areas having better trueness than internal areas. The 5-axis milling machine had high precision, which was minimally affected by the ceramic type, milling protocol, or crown area.


前言: 目的: 探讨不同陶瓷材料的不同铣削方案对磨制烤瓷冠的真伪及精度的影响。 材料和方法: 使用一名需要陶瓷冠的患者的明确印象来制作四十个湿硬铣削方案研磨的玻璃陶瓷冠 (VITABLOCS mark II,Vita Zahnfabrik) 和40个干软铣削方案研磨的氧化锆冠 (inCoris TZI,Dentsply,Sirona),使用5轴铣床 (inLab MC X5; Dentsply Sirona)。用3D评估软件 (Geomagic Control X,3D系统) 评估不同冠部区域的真实性和精度。采用独立t检验对2种牙冠类型进行统计学分析,并对每个牙冠的牙冠区域进行Bonferroni检验后进行方差分析。 结果: 玻璃烤瓷冠全冠面积均高于氧化锆冠面积 (p <0.05)。各冠类型的冠面积具有显著不同的真度值 (p <0.001,玻璃冠F = 175.17,p <0.001,氧化锆冠F = 35.04)。玻璃冠的精度为3.78微米,而氧化锆冠的精度为4.12微米,两种冠的精度差异范围从内表面的0.32微米到边缘表面的6.5微米。 结论: 陶瓷材料的类型和铣削方案影响铣削冠的真度,硬磨玻璃冠的真度高于软磨氧化锆冠。与参考设计和玻璃牙冠相比,软磨氧化锆牙冠通常被覆盖。然而,玻璃冠在薄而深的区域表现出更多的下磨。冠区影响真伪,外部区域的真伪优于内部区域。5轴铣床具有高精度,受陶瓷类型,铣削方案或冠面积的影响最小。



作者列表:["Juan-Carlos PM","Perla-Lidia PP","Stephanie-Talia MM","Mónica-Griselda AM","Luz-María TE"]

METHODS::The ATP binding-cassette superfamily corresponds the mostly transmembrane transporters family found in humans. These proteins actively transport endogenous and exogenous substrates through biological membranes in body tissues, so they have an important role in the regulation of many physiological functions necessary for human homeostasis, as well as in response regulation to several pharmacological substrates. The development of multidrug resistance has become one of the main troubles in conventional chemotherapy in different illnesses including cancer, being the increased efflux of antineoplastic drugs the main reason for this multidrug resistance, with a key role of the ABC superfamily. Likely, the interindividual variability in the pharmacological response among patients is well known, and may be due to intrinsically factors of the disease, genetic and environmental ones. Thus, the understanding of this variability, especially the genetic variability associated with the efficacy and toxicity of drugs, can provide a safer and more effective pharmacological treatment, so ABC genes are considered as important regulators due to their relationship with the reduction in pharmacological response. In this review, updated information about transporters belonging to this superfamily was collected, the possible role of these transporters in cancer, the role of genetic variability in their genes, as well as some therapeutic tools that have been tried to raise against main transporters associated with chemoresistance in cancer.

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作者列表:["Sawada H","Oeda T","Kohsaka M","Tomita S","Umemura A","Park K","Yamamoto K","Kiyohara K"]

METHODS:BACKGROUND:Cholinergic neurotransmission regulates neuroinflammation in Parkinson disease (PD). RESEARCH DESIGN AND METHODS:The authors conducted a delayed-start study of donepezil for cognitive decline in non-demented PD patients. The study consisted of a 96-week randomized placebo-controlled double-blind phase 1, followed by a 24-week donepezil extension phase 2. The primary outcome measure was a change in the Mini-Mental State Examination (MMSE) at week 120. RESULTS:A total of 98 patients were randomly allocated to the early-start (donepezil-to-donepezil) and delayed-start (placebo-to-donepezil) groups. Mean (SD) of the baseline MMSE was 27.6 (2.0) and 28.0 (2.1), respectively. MMSE change at week 120 was better in the early-start group than in the delayed-start group, but the difference was not significant. The MMSE declined in apolipoprotein ε4 carriers, but not in non-carriers, and the factor interaction (intervention × ε4 genotype) was highly significant (P < 0.001). Analyzed with the interaction, the difference was significant (group difference 1.95 [0.33 to 3.57], P = 0.018). The MMSE decline slope in phase 1 was significantly better in the early-start group than in the delayed-start group (P = 0.048). CONCLUSIONS:Cognitive function deteriorated in ε4 carriers, but not in non-carriers, and early-start donepezil may postpone cognitive decline in the former.

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作者列表:["Louvrier A","Terranova L","Meyer C","Meyer F","Euvrard E","Kroemer M","Rolin G"]

METHODS::Since the discovery of dental pulp stem cells, a lot of teams have expressed an interest in dental pulp regeneration. Many approaches, experimental models and biological explorations have been developed, each including the use of stem cells and scaffolds with the final goal being clinical application in humans. In this review, the authors' objective was to compare the experimental models and strategies used for the development of biomaterials for tissue engineering of dental pulp with stem cells. Electronic queries were conducted on PubMed using the following terms: pulp regeneration, scaffold, stem cells, tissue engineering and biomaterial. The extracted data included the following information: the strategy envisaged, the type of stem cells, the experimental models, the exploration or analysis methods, the cytotoxicity or viability or proliferation cellular tests, the tests of scaffold antibacterial properties and take into account the vascularization of the regenerated dental pulp. From the 71 selected articles, 59% focused on the "cell-transplantation" strategy, 82% used in vitro experimentation, 58% in vivo animal models and only one described an in vivo in situ human clinical study. 87% used dental pulp stem cells. A majority of the studies reported histology (75%) and immunohistochemistry explorations (66%). 73% mentioned the use of cytotoxicity, proliferation or viability tests. 48% took vascularization into account but only 6% studied the antibacterial properties of the scaffolds. This article gives an overview of the methods used to regenerate dental pulp from stem cells and should help researchers create the best development strategies for research in this field.

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