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At least 613 records · Page 34Linked to original sources
PubMed2006

[The study on biocompatibility of diamond-like carbon coated nickel-titanium shape memory alloy with osteoblasts cultured in vitro].

OBJECTIVE: To investigate the biocompatibility of diamond-like carbon (DLC) coated Nickel-Titanium shape memory alloy with osteoblasts cultured in vitro. METHODS: Rabbit's osteoblasts were incubated with DLC-coated Nickel-Titanium shape memory alloy disks and uncoated ones of equal size for 5 days. The control group (without shape memory alloy in culture media) was performed simultaneously. The cultured cells were counted and graphed. The samples from culture media were collected and the concentrations of alkaline phosphatase (ALP) and nickel (Ni2+) were measured from the 1st to 5th day respectively. RESULTS: The proliferation of osteoblasts and the concentration of ALP in both DLC-coated group and control group was higher than uncoated group. The proliferation of osteoblasts on the 3rd, 4th, and 5th day in both DLC-coated group and control group was significantly higher than that in the uncoated group (P < 0.05). The concentration of ALP in DLC-coated group on the 2nd, 3rd, and 5th day and in the control group on the 3rd, 4th, and 5th day was significantly higher than that in the uncoated group (P < 0.05). The concentration of Ni2+ on the 3rd, 4th, and 5th day was significantly lower than that in the uncoated group (P < 0.05). CONCLUSION: DLC- coated Nickel-Titanium shape memory alloys appears to have better biocompatibility with osteoblast cultured in vitro compared to uncoated ones.

Alloys↗
PubMed2006

High-risk pregnancies in Diamond-Blackfan anemia: a survey of 64 pregnancies from the French and German registries.

We reviewed 64 pregnancies in 26 women with Diamond-Blackfan anemia (DBA) included in the French and German DBA registries. Complications were seen in 42 pregnancies (66%) and included abortion, pre-eclampsia, in utero fetal death, intrauterine growth retardation, retroplacental hematoma, pre-term delivery and fetal malformations. Of the 34 children (53%) born alive, 13 had DBA. No correlations were found between pregnancy outcome and features of either maternal or child DBA. Pregnancies in DBA-affected women are at high risk, especially for complications likely to be of vascular-placental origin. Careful monitoring with prevention of severe anemia and early introduction of aspirin is suggested.

Anemia↗
PubMed1991

[The effect of diamond grinding instrument of different grit on dental hard tissue].

Under practice-related conditions 100 human molars and premolars were prepared with diamond grinding instruments of different grit. We obtained the smoothest surfaces by using the extra-fine grit at 250,000 rpm, thus indicating the suitability of these instruments for finishing cavity walls especially at high rotating speeds. Only slight differences were found between medium and coarse grit. The time saved by choosing the super-coarse grit for preparation is largely compensated because finishing of rough cavity walls will take longer. No constant effect of the rotating speeds on the depth of roughness of cavity walls was observed.

Carbon↗
PubMed2006

[The effect of surface free energy parameters of diamond-like carbon films deposited on medical polyethylene terephthalate on bacterial adhesion].

Diamond-like carbon (DLC) films were deposited by acetylene plasma immersion ion implantation-deposition (PIII-D) on biomedical polyethylene terephthalate (PET). The capacities of Staphylococcus aureus (SA), Staphylococcus epidermidis (SE), Escherichia coli (EC), Pseudomonas aeruginosa (PA) and Candida albicans (CA) for adhesion to PETs are quantitatively determined by the plate counting and Gamma-ray counting of 125I radio labeled bacteria in vitro. The results indicate that the capacities of five types of bacteria for adhesion to PETs are all suppressed by C2H2 PIII-D (P<0.05). The surface energy components of the various substrates and bacteria are calculated based on measurements in water, formamide and diiodomethane and Lifshitz-van del Waals/acid-base approach (LW-AB). The surface free energies obtained are used to calculate the interfacial free energies of adhesion (deltaF(adh)) of five kinds of bacteria on various substrates, and the results show that it is energetically unfavorable for bacterial adhesion to the DLC films already deposited on PET by C2H2 PIII-D.

Bacterial Adhesion↗
PubMed2006

Use of CVDentUS diamond tips for ultrasound in cavity preparation.

AIM: The aim of this study was to evaluate the use of CVDentUS tips for preparing cavities with ultrasound by dentists certified to use the Chemical Vapor Deposition (CVD) system. METHODS AND MATERIALS: One thousand sixty (1060) questionnaires were sent via e-mail inquiring about the use of the system with regard to the indication for use, need for anesthesia, final form of cavity preparation, and tip wear. RESULTS: Of the valid answers, 81.4% of the dentists used this system for tooth preparation in up to 60% of cases treated. For these procedures, 17.8% did not require use of local anesthesia while using the system. The final form of preparation compared to high speed diamond tips was considered to be more conservative by 48.3% of the certified professionals. With regard to wear, tip and/or adapter fractures, and low cutting speed, 44.4% of users reported problems. DISCUSSION: The CVD system seems to be used for tooth cavity preparation by the majority of the certified dentists. This is due to the resultant conservation of tooth structure despite the necessity of anesthesia and the limitations with regard to the lack of cutting efficiency of CVDentUS and tip wear. CLINICAL SIGNIFICANCE: The CVD system seems to present limitations with regard to cutting efficiency, wear, and the use of anesthesia in a majority of restorative procedures.

Dental Cavity Preparation↗
PubMed2006

Translational efficiency in patients with Diamond-Blackfan anemia.

BACKGROUND AND OBJECTIVES: Diamond-Blackfan anemia (DBA) is a rare congenital pure red cell aplasia characterized by normochromic macrocytic anemia, reticulocytopenia, and normocellular bone marrow with a selective deficiency of erythroid precursors. Ribosomal protein S19 (RPS19), currently the only gene associated with DBA, is mutated in 25% of DBA patients, but its role in erythropoiesis is unknown. We attempted to elucidate the importance of RPS19 in translation in relation to the pathogenesis of DBA. DESIGN AND METHODS: We measured translation and proliferation rates in unstimulated and phytohemagglutinin (PHA)-stimulated lymphocytes isolated from DBA patients, as well as in K562 cells expressing several RPS19 mutants to directly test the effect of RPS19 mutations on translation. The effect of leucine on overall translation was also studied. RESULTS: We found that the level of translation was on average 48-73% of controls in both unstimulated and PHA-activated DBA lymphocytes irrespective of mutations in RPS19. The addition of leucine increased the translational level in RPS19-non-mutated DBA cells, but not in cells with an RPS19 mutation. In unstimulated DBA cells, proliferation was significantly impaired in both RPS19-mutated and non-mutated cells, but in both groups could be efficiently activated by PHA. Studies on K562 cells showed that RPS19 mutations affecting RPS19 conserved arginines R56Q and R62Q could significantly inhibit the rate of protein synthesis, indicating the importance of RPS19 in translation. INTERPRETATION AND CONCLUSIONS: Our results indicate that inefficient translation may be the main cause of DBA, and administration of leucine may be beneficial for at least some DBA patients.

Anemia, Diamond-Blackfan↗
PubMed1989

[Cool diamond burrs in test conditions].

In almost 500 differentiated measurements of temperature and grinding performance of diamond grinding tools with and without cooling grooves--in conjunction with both a turbine and a high-speed angle piece--under practical conditions, it is demonstrated how many-sided this complex of issues is; it is further demonstrated that it is not possible to generally conclude that all so-called CD grinding tools have better cooling capabilities and/or that they are better suited to prevent excessive heat generation in comparison with grinding tools without cooling grooves. This is equally applicable to grinding performance.

Carbon↗
PubMed1978

Congenital hypoplastic anemia (Diamond-Blackfan syndrome) terminating in acute myelogenous leukemia.

A 31-yr-old female with congenital hypoplastic anemia (Diamond-Blackfan syndrome) whose long course terminated in acute myelogenous leukemia is described. In contrast to Fanconi anemia, malignant transformation rarely occurs in congenital hypoplastic anemia. This patient's diagnosis of congenital hypoplastic anemia is supported by her clinical course, absence of renal abnormalities, a negative family history for hematologic disorders, normal chromosome studies, failure of her skin fibroblasts to transform in culture with SV-40 virus, macrocytic erythrocyte indices, erythrocyte enzyme studies, and bone marrow findings. Only two other cases of malignancy have been reported in patients with congenital hypoplastic anemia. The development of malignancy in these patients suggests that malignant transformation may be a concern in the long-term progression of congenital hypoplastic anemia.

Adult↗
PubMed1984

Experimental synovitis induced by aluminium phosphate in rabbits. Comparison of the changes produced in synovial tissue and in articular cartilage by aluminium phosphate, carrageenin, calcium hydrogen phosphate dihydrate, and natural diamond powder.

The goal of this experimental study was to examine the effect on articular tissue of tribasic aluminium phosphate (crystalline and amorphous forms) after intraarticular injection in rabbit and to compare it with that of various phlogistic compounds such as carrageenin, calcium hydrogen phosphate dihydrate and diamond powder, as a control. Synovium and cartilage were studied with light microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive micro-analysis (EDM). Crystalline and amorphous aluminium phosphate could induce a synovitis with articular effusion in rabbits. With TEM, lysosomal inclusions of phagocytosed material were observed. Through SEM coupled with EDM, aluminium associated with phosphate was found in cellular elements.

Aluminum Compounds↗
PubMed1982

Diamond knife.

We present a new diamond knife which allows for reasonably precise incisions in cornea or sclera. The knife may be ultrasonically cleaned and is sharper than any metal knife whose edge we have examined to date by scanning electron microscopy. The edge is approximately 0.1 micron in width, compared to 1-5 micron width edges of most metal knives. We feel that this prototype will allow investigators to recommend special modifications to the manufacturer of their own choice.

Carbon↗
PubMedDate not supplied

[State of accommodation depending on age of emmetropic and hypermetropic subjects engaged in diamond sorting].

Accommodation was studied in 449 diamond sorters aged 17 to 51 engaged in this work for 1 to 34 years with emmetropic and hypermetropic refraction. Questionnaires helped detect subjects who had no complaints of vision (group A) and those with asthenopia complaints (group B). In both groups, in emmetropic and hypermetropic subjects, the furthest point of clear vision was converging the eye by 1.96 +/- 0.04 diopters on an average, that is, there was pseudomyopia. In hypermetropic subjects with occupational ophthalmopathy the nearest point is withdrawn starting from the age of 31-35 till it merges with the furthest point in subjects over 45, that is, the accommodation volume becomes nearly nuel. The results of this study contradict the assumption existing in ophthalmology about an earlier onset of presbyopia in hypermetropia than in other types of refraction. Early correction of near vision is connected with superimposition of accommodation deterioration in ametropia. It is recommended to carry out rehabilitative measure as soon as the first asthenopia signs manifest; these measures should be aimed at weakening of refraction by the site of the furthest clear vision point. In subjects aged 31-35 with occupational ophthalmopathy refraction by the nearest clear vision point should be enhanced if possible.

Accommodation, Ocular↗
PubMed1993

Diamond-like carbon as biological compatible material for cell culture and medical application.

Ion beam assisted diamond-like carbon (DLC) films have been used for growing the human hematopoietic myeloblastic ML-1 cells and human embryo kidney 293 cells in the control environment. DLC films were directly deposited onto the P-35 plastic dishes by impacting the high kinetic energy (1000 eV) of methane ions at room temperature. The present results showed that both ML-1 and HEK 293 cells continuously grow with and without DLC films. It has demonstrated that human cells proliferated on DLC film with very high viability and DLC material had no toxicity to cultured human ML-1 and HEK 293 cells. We conclude that DLC film is a biological compatible material for potential cell culture matrix and bio-medical applications.

Biocompatible Materials↗
PubMed1993

[The effects of sterilization with microwaves on diamond burs].

The author evaluates microwave sterilization effects on diamond dental burs by viewing them under stereomicroscope before and after sterilization cycles. After fifteen cycles it has been observed that no damage was present. Such sterilizing system can be used as an alternative method against disposable burs. This study does not treat about its biological efficacy.

Carbon↗
PubMed1996

[A proposed clinical method for the finishing of composite-resin restorations by means of diamond burs and abrasive disks and strips: a SEM analysis].

INTRODUCTION: Composite resin is the most cosmetic material used in restorative dentistry. Its functional and cosmetic features are enhanced by an appropriate finishing. A non finishing surface is very rough, allowing therefore plaque accumulation and pigments deposition deriving from feeding. MATERIALS AND METHODS: In this study the authors performed several finishing methods using diamond burs, abrasive disks and abrasive strips. All the samples were analyzed by means of SEM at 100x, 300x and 500x. RESULTS AND DISCUSSION: The results showed several differences among tested samples according to the material and the technique used. Satisfactory finishing is performed by the association of medium and fine sizes finishing burs (Intensiv 50/D4 and Intensiv 40/D4) and medium and fine abrasive disks (Sof Lex Pop On 3M 1981 M and F), or by medium and fine finishing abrasive burs and abrasive strips (Sof Lex 3M Coarse-Medium/Aluminum Oxide N. 1954-150 and Fine-Superfine N. 1956-120).

Composite Resins↗
PubMedDate not supplied

Efficient endodontic access: rapid pulpotomy with a safe-ended diamond.

A correct access opening is the key to endodontics. An adequate anatomical access preparation maximizes cleaning, shaping, and obturation. The major objectives of access preparation are straight line access to the apical area, conservation of tooth structure, and unroofing of the pulp chamber. The safe-ended diamond bur technique provides an efficient and rapid means to obtain the objective of access preparation in posterior teeth.

Bicuspid↗
PubMed1997

An evaluation of operator preference of diamond burs in coronal tooth preparation.

Three postgraduate prosthodontic students served as clinicians/evaluators in a study rating their preferences for three different diamond cutting instruments from three manufacturers. Each evaluator prepared the axial walls of complete veneer crowns on extracted molar teeth and then ranked their preference of the instruments. To prepare nine teeth, each of the three instruments was used in random order and without knowledge of the specific manufacturer. The methodology for analyzing the evaluators' preferences and the results are discussed.

Analysis of Variance↗
PubMed1984

Endothelial damage in monkeys after radial keratotomy performed with a diamond blade.

Anterior radial keratotomy was performed with a diamond blade in ten rhesus monkey eyes. Results were compared with those of a previous study in which a metal blade was used. Histologic assessment showed endothelial degeneration, but fewer edematous endothelial cells, than in the previous study. Specular microscopy demonstrated statistically significant endothelial cell losses (7.99%), when preoperative and three-month postoperative values were compared. Autoradiography showed little cell division in the endothelial cell layer. Cell loss seemed to be repaired mainly by the spreading of neighboring cells. Endothelial cell division is also limited in humans, and the cumulative loss of cells due to surgical trauma combined with continuous damage-related losses and later age-related reductions in cell numbers could produce corneal decompensation in some patients years after radial keratotomy.

Animals↗