نتایج جستجو برای: enamel crack
تعداد نتایج: 34861 فیلتر نتایج به سال:
This study investigated the prevalence of enamel hypoplasia and dental caries and the relationship between the two diseases in all 4- to 6-year-old Australian Aboriginal children of the Tiwi tribe on Bathurst Island. Seventy-nine of 80 children (99%) had enamel hypoplasia, with a mean of 12.0 +/- 4.1 hypoplastic teeth per child. Dental caries was noted in 66 (83%) of children and the mean numbe...
Matrix metalloproteinase 20 (MMP20) and kallikrein-related peptidase 4 (KLK4) are secreted proteinases that are essential for proper dental enamel formation. We characterized and compared enamel formed in wild-type, Mmp20 (-/-), Klk4 (-/-), Mmp20 (+/-) Klk4 (+/-), and Mmp20 (-/-) Klk4 (-/-) mice using dissecting and light microscopy, backscattered scanning electron microscopy (bSEM), SEM, micro...
This paper investigates the phenomenon of slant fracture observed in stable tearing tests of many ductile materials, where an initially flat crack, loaded under remote Mode I conditions, tends to grow into a slant crack and stay in the slant configuration until final fracture. In an effort to identify potential reasons why cracks prefer to grow in a slant manner, three-dimensional finite elemen...
Enamel, the outermost layer of teeth, is an acellular mineralized tissue that cannot regenerate; the mature tissue is composed of high aspect ratio apatite nanocrystals organized into rods and inter-rod regions. Amelogenin constitutes 90% of the protein matrix in developing enamel and plays a central role in guiding the hierarchical organization of apatite crystals observed in mature enamel. To...
initial cracks occur in high strength concrete sleepers for various reasons, such as shrinkage and wrong curing and long lifetime of over 50 years of sleepers. these cracks may lead to complete failure of the structure. in order to more accurately design the sleepers, fracture mechanics (not strength of materials) should be incorporated. in order to achieve this purpose, it is important to fore...
Most of what we know about the timing of human enamel formation comes from radiographic studies on children of known age. Here, we present new longitudinal data derived from a histological analysis of tooth enamel. Two samples, one from southern Africa and one from northern Europe, contained all anterior and molar tooth types. Two further samples contained only one tooth type: canines from a me...
An evaluation on the effects of 37% phosphoric acid and self – etching primer on shear bond strength of enamel Dr. A. Davari* - Dr. H. Hajizadeh* - Dr. H. Sharifikhatoonabadi** *- Assistant Professor of Operative Dentistry Dept. - Faculty of Dentistry - Yazd University of Medical Sciences. **- Dentist. Background and Aim: The goal of this study was to evaluate the effects of 37% phosphoric acid...
Background and Aims: Considering the preventive and therapeutic effects of resin infiltration (RI) and the unknown effect of bleaching on the enamel treated with this method, this in-vitro study aimed to assess the effect of bleaching on color stability of enamel lesions treated with RI. Materials and Methods: In this in-vitro, experimental study, enamel-dentin samples measuring 5×5×3 mm were ...
Although, experimental studies have reported fracture at the corner of Steel Plate Shear Walls (SPSW), no study has been performed to investigate the crack effect, yet. Therefore, in this paper, the effect of crack at the corner of SPSWs on the seismic behavior of the system was investigated. Two probable cracks, that have been studies at the corner of SPSWs utilizing extended Finite Element me...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید