1,721,304 research outputs found
Morphological analysis and cellular growth evaluation related to different implant surface treatment: an in vitro investigation.
No full textALP enzymatic activity related to different implant surface microtopographies
No full textThe aim of this study was an in vitro investigation of the Alkaline
Phosphatase (ALP) enzymatic activity related to different surface
treatments applied to ten implant systems in order to assess if the
interaction between cells and implant (osteoblastic proliferation and
differentiation) was influenced by the surface structure and/or
surface composition of the fixture. The originality of this study
was that all implants were tested as manufactured for clinical use.
The implant systems object of this study divided by the surface
treatment were the following: Machined: Mk III Branemark;
Sandblasted: Ankylos, Silhouette and Galant (experimental fixture);
Etched: Osseotite, Mac System,MK 4 (experimental fixture),
ITI; Oxided: Ti Unite, Pilot. We used Sa-OS2 cultured osteoblasts
and we analyzed n14 fixtures for each implant system (n11 fixture
for the cellular growth curve and n13 fixtures for the ALP activity).
After 14 days the assay for the ALP activity was carried out
according to Wataha et al. (JBMR, 1997) After the cellular growth
evaluation in a Burker’s hemocytometer chamber we quantify by a
spectrophotometer at 405nm the absorbance value for each sample
(the absorbance value indicate the amount of the conversion by ALP
of the P-Nitro-Phenyl-Phosphate into P-Nitro-Phenol) and we
corrected the mean value for cell number determined before. The
data were statistically analyzed by ANOVA and Post hoc Scheffe`
Test. Within the limits of the in vitro investigations we can
conclude that:
The etched surfaces shown more cellular growth than others.
The sandblasted surfaces shown the smallest amount of
cellular proliferation but a very high differentiation (according
to Postiglione et al 2003 that found an inverse correlation
between the two factors)
We found a statistically significant difference in ALP activity
only between oxided and etched surfaces (p < 0.05)
The sandblasted and oxided surfaces shown more osteoblastic
differentiation (more ALP enzymatic activity)
Themachined surface is competitive, as regard the osteoblastic
differentiation, with the rougher surfaces.
Actually it’s still difficult to recommend a particular rougher
surface
The role of surface implant treatments on the biological behavior of SaOS-2 osteoblast-like cells. An in vitro comparative study
No full textObjectives The aim of this study was an in vitro comparison of osteoblast adhesion, proliferation and differentiation related to six dental implants with different surface characteristics, and to determine if the interaction between cells and implant is influenced by surface structure and chemical composition.
Material and Methods Six types of implants were tested, presenting four different surface treatments: turned, sandblasted, acid-etched, anodized.
The implant macro- and micro-structure was analyzed by SEM, and the surface chemical composition was investigated by EDX analysis.
SaOS-2 Osteoblasts were used for the evaluation of cell adhesion and proliferation by SEM, and cell viability in contact with the various surfaces was determined by cytotoxicity MTT assays. Alkaline Phosphatase (ALP) enzymatic activity in contact with the six surfaces was evaluated. Data were normalized after cell count and statistically analyzed using one-way ANOVA and Sheffè’s post hoc test.
Results All the implants tested supported cell adhesion, proliferation and differentiation, revealing no organic contaminants nor cytotoxicity effects. The industrial treatments investigated changed the implant surface microscopic aspect and SaOS-2 cell morphology appeared to be influenced by the type of surface treatment at 6, 24 and 72 hours of growth. SaOS-2 cells spread more rapidly on sandblasted surfaces. Turned surfaces showed the lowest cell proliferation at SEM observation.
Sandblasted surfaces showed the greatest ALP activity values per cell, followed by turned surfaces (P<.05).
Conclusions On the base of this in vitro investigation, differently surfaced implants affected osteoblast morphology, adhesion, proliferation and differentiation. Sandblasted surfaces promoted the most suitable osteoblast behavior
Chemical EDX analyis of different surface modified implant systems
No full textThe main used processes of modification of the implant surface are:
machining, sandblasting, etching and oxiding. They have the purpose
to reduce the times of the osseointegration and to improve its
quality. The aim of this study was to investigate how these processes
macroscopically (at 5 m depth) modify the implant surface and its
chemical composition. The originality of this investigation was that
all the implants were tested as manufactured for clinical use.
Ten of the major used implant systems were the object of this
study: they were divided by the surface treatment in: Machined:
Mk III Branemark; Sandblasted: Ankylos, Silhouette and Galant (experimental fixture); Etched: Osseotite, Mac System, MK 4
(experimental fixture), ITI; Oxided: Ti Unite, Pilot . Each fixture
was analyzed by SEM (Leo 420) at 50x and 5000x at 15 KV of
scanning power. The EDX analysis (Energy Dispersion X-ray
analysis) was considered to study eventual inclusion of material
left from the processes of surface modification, cleaning and
decontamination. The EDX analysis scans the implant surface at
a 5m of depth and is performed during SEM observations using a
specific micro tip that identify the chemical elements.
The results from SEM analysis shown macroscopical residuals of
aluminum oxide on the SLA surface and some oil spots on the
machined surface.
The results from the EDX analysis are below summarized:
Sandblasted surfaces showed particles of Alumina
Oxided surfaces showed very high peaks of O2
Etched surfaces showed only Titanium peaks
Machined surfaces showed low peaks of O
Osteoblast proliferation and differentiation on different bone graft materials
No full textAim of this study was to investigate the biological activity of eight
bone graft materials analyzing their influence on osteoblast proliferation
and differentiation. The materials were classified as:
Synthetic materials: Sintbone (Ghimas), Fisiograft (Ghimas) and
Ostim (Heraeus-Kulzer).
Animal-derived materials: Biogen (Biotek), BioOss (Geistlich)
and Osteograft (Dentsply-Friadent).
Mixed materials: Biostite (Vebas) and PepGen P-15 (Dentsply-
Friadent). The bone graft materials have been tested by the MTT
test (proliferation quantitative analysis) using osteoblasts SaOS-
2 coming from human osteosarchoma. Afterwards the ALP
enzymatic assay was performed. Both tests were repeated three
times for each specimen at 3 and 5 days. After the quantitative
evaluation of the cellular proliferation by MTT test, we quantified
the absorbance value for each specimen using a spectrophotometer
at 405nm and we calculated the mean ALP value
for each specimen, for each group of materials and the ALP/
MTT ratio. Data were statistically analyzed (ANOVA one way
and post hoc Scheffe` tests). The mean values of MTT (proliferation
test) and of ALP (differentiation test) were different between
tested materials. Within the limits of the in vitro studies
it can be concluded that: Tested bone graft materials induced
different amounts of cell proliferation and differentiation. Synthetic
and animal-derived materials showed the best values of
both parameters considered (proliferation and differentiation)
statistically different from mixed materials (P < 0.05). In particular,
Biostite (mixed materials) showed statistically lowest
values of proliferation and differentiation (this material has a
cytotoxic effect) with respect to the others (P < 0.001). Synthetic
materials, as well as animal-derived ones could be used
An in vitro study of the tensile strength of a new titanium root post with respect to the type of luting cement used
No full textBACKGROUND: Assessing the retentive capabilities of a new titanium root post (Optipost, Komet-Gebr. Brasseler, GmbH and Co. KG Lemgo, Germany) with a decreasing diameter shape (turret like) and how these can be improved by the choice of fixing cement. METHODS: The tensile strength was assessed in relation to the type of cement used. The following cements were tested: Compolute composite cement (Espe), C/B Crown & Bridge Luting Composite (Bisco), Diamond Link cement (DRM) with Harvard cement as a control. The cementing procedures laid down by the manufacturers were followed in the case of each cement. The results of the traction tests were analysed and compared statistically and a SEM evaluation of the root/cement and cement/post interface was carried out. RESULTS: The results showed that the highest absolute mean value (best performance) was Diamond Link cement (46.48+/-14.31 kg) which also came out best in the statistical analysis (Scheffe Test p=0.007). Analysis of the samples at the SEM confirmed the results of the traction tests. CONCLUSIONS: The characteristic > form of the Optipost root post and the sanding of the surface would appear to be important factors which, together with the adhesive cementing technique, lead to a high decementing resistance
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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