Background: This in vitro study was carried out to evaluate the effects of various veneering dentin ceramic thicknesses and repeated firings on the color of lithium disilicate glass-ceramic (IPS e.max Press) and zirconium-oxide (IPS ZirCAD) all-ceramic systems, measured by clinical spectrophotometers (Easyshade Advance 4.0) . Materials and methods: The 72specimens cube-shaped have the dimension of about 11 mm in width, 14 mm in length, 1mm in thickness, these cores divided into 3 groups according to the type of material each group have (24)core specimens. Each group had been divided into three sub-groups (each having 8 specimens) according to veneering with dentin ceramic thicknesses: as 0.5, 1, or 2 mm (n=8). IPS e.max press and ZirCAD cores group had been veneered with IPS e.max Ceram dentin ceramic shade A2 according to manufacturer’s instructions and the metal group had been veneered with IPS classic dentine ceramic with shade A2 according to manufacturer’s instructions. Repeat firings (3, 5 and 7 times) had been applied on all the specimens. Color differences among ceramic specimens had been measured using a clinical spectrophotometer (VITA Easyshade); the color data had been expressed according the Vita Classic shade guide. Results: The shade of all specimens had been compared inside the subgroups and with the main groups. The percentage of color agreement among the subgroups showed the color of all ceramic systems had been affecting by firing interval, the ceramic thickness and brand of ceramic. The number firings intervals applied on the all ceramic system has a significant effect on the final color, the increase of firing number change the color to a darker and reddish color. The 5th firing interval is the point at which the major color changes happened (darker shade), and in next interval (7th firing) less color changes happened. The thickness of veneering ceramic affected the color significantly. The 0.5 mm specimens in all groups showed the highest percentage of agreement (less color changes) after firing intervals, then the 1mm came and the least percentage of agreement ( highest color changes ) was the 2 mm specimens. The Brand of veneering ceramic and the type of core record a significance difference in color changes when exposed to firing heat. Conclusion: With limit of this study, the final color of the all ceramic system definitely affected by the number of firing cycle exposed to, and the veneering ceramic thickness have a clear effect on the final shade of the all ceramic tested.
Background: (ABO) Blood type have an effect on general health including oral health as salivary physicochemical characteristics differ among different type of blood and as consequence these affect the severity of dental caries. The aim of the present study is an assessment of the prevalence of caries experience among different blood type in relation to salivary physicochemical characteristic. Materials and Methods: Two hundred and fifty females' college students in Al-Qadisyia University aged 18 years old were selected on random basis; they were divided to four groups according to their blood type, Dental experience was diagnosed and recorded according to DMFs (Mülemman, 1976) Index, this allows recording decayed lesion by severity. A su
... Show MorePoly-ether-ether-ketone (PEEK) was introduced in dentistry as an alternative to metal alloys.
To assess the effectiveness of PEEK-fixed retainers in preserving the stability of mandibular anterior and participant satisfaction as compared to the Dead-soft coaxial fixed retainer (DSC).
A single-centre, two-arm parallel groups
Background: With the increasing demands for adult orthodontics, a growing need arises to bond attachments to porcelain surfaces. Optimal adhesion to porcelain surface should allow orthodontic treatment without bond failure but not jeopardize porcelain integrity after debonding.The present study was carried out to compare the shear bond strength of metal bracket bonded to porcelain surface prepared by two mechanical treatments and by using different etching systems (Hydrofluoric acid 9% and acidulated phosphate fluoride 1.23%). Materials and Methods: The samples were comprised of 60 models (28mm *15mm*28mm) of metal fused to porcelain (feldspathic porcelain). They were divided as the following: group I (control): the porcelain surface left u
... Show MoreBackground: Depression is a common mental disorder that presents with depressed mood;it can become chronic or recurrent and affect dental health .Thus this research aimed to assess the prevalence and severity of dental caries among students with different grade of depression in relation to physicochemical characteristics of stimulated whole saliva. Materials and methods: The total sample involved for depression status assessment is composed of 800 students for both gender aged 15 years old that were selected randomly , This was performed using children depression inventory (CDI) index that divided the students into four groups of depression(low or average grade, high average grade, elevated grade and very elevated grade). The diagnosis and
... Show MoreThe habitat type and food availability always influence the population size of many
organisms. Bird’s feeding pattern should be abstracted to complete avian community structure
data. The agronomy main research farm of Orissa University of Agriculture and Technology
is a well-managed multi-crop agro-ecosystem which provides a suitable ground for ecological
research. In a multi-crop farmland, the association of Barn Swallow Hirundo rustica Linnaeus,
1758, with the Indian mustard Brassica juncea (L.) Czernajew, 1859 crops have been
recorded for the first time while hovering only on this field. A flock of Barn swallows was
recorded in 32 field visits while flying continuously over the Indian mustard field after
flow
In this paper, we introduce and study new types of soft open sets and soft closed
sets in soft bitopological spaces (X,~ ,~ ,E) 1 2 , namely, (1,2)*-maximal soft open
sets, (1,2)*-maximal soft (1,2)*-pre-open sets, semi (1,2)*-maximal soft (1,2)*-preopen
sets, (1,2)*-maximal soft closed sets, (1,2)*-maximal soft (1,2)*-pre-closed
sets, (1,2)*-minimal soft open sets, (1,2)*-minimal soft (1,2)*-pre-open sets, (1,2)*-
minimal soft closed sets, (1,2)*-minimal soft (1,2)*-pre-closed sets, and semi (1,2)*-
minimal soft (1,2)*-pre-closed sets. Also, properties and the relation among these
concepts have been studied.
Los nombres propios nombran a un ser o a un objeto, distinguiéndolo de los demás seres de su misma clase, se escriben siempre con letra mayúscula a principio de palabra. Los lingüistas hacen mayor hincapié en las divergencias de referencia, entre nombres propios y nombres comunes. Así, suele decirse que el sustantivo propio no tiene como referente ningún concepto. El asunto de la traducción de los nombres propios parecería una cuestión de gusto personal del traductor pero vemos también que en algunas épocas es más frecuente traducirlos, y en otras, por el contrario, se prefiere dejar esos nombres en su forma original, tal vez con algunas adaptaciones ortográficas. Parecería entonces cuestión de modas. Pero, eviden
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