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Article
Effect of different metal surface treatments on microleakage of the two types of acrylic resin: Heat cure and light cure at Co/Cr interface

Authors: Shatha S. Al-Ameer --- Firas A. Farhan
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2009 Volume: 21 Issue: 3 Pages: 31-36
Publisher: Baghdad University جامعة بغداد

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Abstract

ABSTRACT
Background: The microleakage (M.L) at the metal-resin interface in a removable partial denture may results in
discoloration, fluid percolation, and acrylic resin deterioration. Enhancing resistance to microleakage at this interface
may improve the long-term union between the two materials (alloy and acrylic resin). The aim of this study was to
determine the effect of various metal surface treatments on microleakage and bonding between the metal alloy
and acrylic resin used in the fabrication of a removable partial denture.
Materials and Methods: Sixty rectangular Co/Cr samples (50 mm x 25 mm x 1 mm) were prepared and they had a
grid pattern, which formed 50 squares which then divided into 2 groups according to the type of acrylic resin
received each one 30 samples {A- for heat cure resin (HCR), B- for visible light cure resin (VLCR)} which were
subdivided according to the type of surface treatments into 3 subgroups each one 10 samples (A1 B1 for Air
Abrasion -- A2 B2 for Metal Prime II (MP II) application -- A3 B3 for combination of Air Abrasion and Metal Primer II
application). Each sample was divided into experimental half (treated) and a control half (untreated). The samples
were thermocycled (3000 cycles, 5 °C to 50 °C with a dwell time of 1 minute) after application of resin, and placed in
sodium fluorescein (0.2 g / 1000 mL) dye solution (Uranine dye, BDH chemicals Ltd Poole, England) for 48 hours. If the
penetration of the dye was not more than half of the square it was recorded half square and if it was more than half
it was recorded as one square.
Results: The results showed that the subgroup that received Air Abrasion + Metal Primer II surface treatments for both
types of resins HC and VLC (A3 and B3) had the least M.L values, followed by the Air Abrasion subgroup (A1 and B1).
Subgroups that received Metal Primer II alone (A2 and B2) showed the highest M.L value than the other subgroups.
All Co/Cr samples with VLCR showed less dye penetration than that of HCR whether with surface treatment or
without suggesting higher binding of resin with the Co/Cr surface.
Conclusion: A combination of air abrasion and MP II for light cure samples showed the highest reduction in M.L
compared to all other types of surface treatments and to HCR. MP II alone was less effective in reduction of M.L than
other surface treatments. The use of VLCR with different metal surface treatments revealed greater reduction in M.L
than that when used HCR even when there is no surface treatment.
Keywords: Co/Cr- heat and light cure resin interface, metal surface treatments, microleakage. (J Bagh Coll Dentistry
2009; 21(4):31-36)

Keywords


Article
Assessment of Calcium Carbonate Coating on Osseointegration of Commercially Pure Titanium Implant by Torque Removal Test and Histomorphometric Analysis

Authors: Mustafa S. Mahmood --- Shatha S. Al-Ameer
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2017 Volume: 29 Issue: 1 Pages: 32-38
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: One of the most important methods to replace lost teeth is dental implants. In order to increase the strength of connection of the implant with the jaw bone to provide early loading after placement, implant is coated by different coating materials that achieved that purpose. The aim of this study was to evaluate the influence of coating CP Ti implant with calcium carbonate on the strength of bone-implant interface after two and six weeks of implantation in rabbit femur bone by torque removal test, histological and histomorphometric analysis.Materials and methods: Coating the surface of commercially pure titanium screws with extra pure synthetic calcium carbonate via electrophoretic deposition method (EPD) was done. The surface of disc samples after coating was checked by optical microscopy, X-ray diffraction examination and measurement of coating thickness. Ten male white French rabbits were prepared for implantation. Forty screws were implanted in the femur bone, two implant screws in each femur bone. The first screw is coated with calcium carbonate and compared with the second uncoated screw. Rabbits are divided into two groups according to the healing periods 2 and 6 weeks. By torque removal, the osseointegration is measured. Single screw from each group was used for histological and Histomorphometric analysis.Results: There was significant increased mean torque removal for screws coated with calcium carbonate compared with uncoated screws. Histological examination showed an increase in the growth of bone cells for coated screws, and the histomorphometric analysis showed an increase in new bone formation percent (NBFP).Conclusion: Coating the surface of the CP Ti implant with calcium carbonate via electrophoretic deposition method had great effect in increasing the osseointegration than uncoated surface.


Article
Water sorption of newly formulated resin-modified and conventional glass ionomer cements

Authors: Shatha S.Al-Ameer --- Saad S.Rahmatallah --- Monadle R. Hadi
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2010 Volume: 22 Issue: 4 Pages: 28-31
Publisher: Baghdad University جامعة بغداد

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Abstract

ABSTRACT
Background: Chemical bonding of glass ionomer cements to tooth structure may be affected by dimensional
changes associated with water absorbed by the material when it is in service inside the oral environment. The aim of
this work was to measure the amount of water absorbed by new formulated cements and compare it with cements
with old formula and two commercial cements.
MATERIALS AND METHODS: Four types of cements were prepared, two were resin-modified light-cured(1 and 2)and
two were conventional chemical-cured (4 and 5). Two commercial cements were used, the first was light-cured
cement 3 (Vivaglass) and the second was chemical-cured cement 6 (Nikang). Five specimens with 9mm diameter
and 4mm height were produced for each type of cement. The weight of each specimen was recorded after 24
hours before immersing in distilled water using very sensitive weight measuring balance with a precision ± 2 mg. A
desiccator was used to absorb water from the specimen material for 24 hours. Then the weight of each specimen
was recorded. The specimens were immersed in 20 milliliters of distilled water at room temperature (25ºC ± 2). The
weight of each specimen was then recorded after different immersing times of five minutes, 10 minutes, 15 minutes,
30 minutes, 60 minutes, one day, three days, one week, 10 day, and two weeks, until no more water absorbed. The
value of water sorption was calculated and the final value was rounded to the nearest 0.1mg/cm2.
RESULTS: Resin modified cements showed higher values of water sorption than those of conventional types of glass
ionomer cements. The highest value of short-term water sorption test was recorded for cements (5) followed by
cement (2). While the lowest value of water sorption was recorded for cement (3)
CONCLUSSION: Resin-modified cements absorb more water than conventional cements. Changing the powder
formula had no clear effect on water sorption, while the resinous components of the liquid had direct effect on
water sorption of the tested cements.
Key words: Water sorption, resin-modified glass ionomer cement, conventional glass ionomer cement. (J Bagh Coll
Dentistry 2010;22(4):28-31).

Keywords


Article
Fluoride release from newly formulated resin-modified and conventional glass ionomer cements

Authors: Shatha S.Al-Ameer --- Saad S.Rahmatallah --- Monadle R. Hadi
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2010 Volume: 22 Issue: 4 Pages: 32-35
Publisher: Baghdad University جامعة بغداد

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Abstract

ABSTRACT
Background: Glass ionomer cement has been used as a restorative material for its chemical bonding to tooth
structure and fluoride release to the surrounding tooth structure. The aim of this study was to see if increasing the
fluoride contents in the cement powder increases the amounts of fluoride released from the set cement.
Materials and Methods: Two types of cements were prepared with increased fluoride contents: cement (1) as lightcured
resin-modified and cement (2) as chemical-cured conventional glass ionomer cements. Two commercial
cements were used for comparison, cement (3) was light-cured (Vivaglass), and cement (4) was chemically-cured
(Nikang). Five specimens for each type of cement were used as discs of 6mm diameter × 3mm height. The
specimens were immersed in artificial saliva solution for 1 day, 1week, 2 weeks, 1 month and 2 months. The amount
of fluoride ions released in the saliva solution was then measured using fluoride ion specific electrode connected to
an ion- analyzer.
Results: The experimental cements (1 and 2) showed increased amounts of fluoride release than commercial
cements (3 and 4). The total amount of fluoride release from the resin-modified cement (1) was more than that of
conventional cement (2) through the time of test.
Conclusion: Fluoride release of prepared cements was higher than that of commercial cements. Increasing fluoride
contents within the cement formula led to increased fluoride release of the set cement.
Key words: Fluoride, resin, glass ionomer cement. (J Bagh Coll Dentistry 2010;22(4):32-35).

Keywords


Article
Histological and histomorphometric analysis of strontium chloride coated commercially pure titanium implant compare with hydroxyapatite coating

Authors: Ghasak H. Jani --- Shatha S. Al-Ameer --- Salam N. Jawad
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2015 Volume: 27 Issue: 1 Pages: 26-31
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: In recent years, the immediate loading of dental implants has become more accepted as a standardprotocol for the treatment of the edentulous area. Success in implant dentistry depends on several parameters thatmay improve phenomenon of osseointegration and new bone formation in close contact with the implant. The aimof study was to evaluate the effect of strontium chloride coating of screw shape commercially pure titanium dentalimplant osseointegration at bone - implant interface by histomorphometric analysis and compare withhydroxyapatite coating at 2 time periods (2 weeks and 6 weeks).Materials and methods: Electrophoretic Deposition Technique (EPD) was used to obtain a uniform coating layer oncommercially pure titanium screws. The tibia of 4 white New Zealand rabbits was chosen as implantation sites. Eachtibia of rabbit received two screws, one strontium chloride coated and one hydroxyapatite coated and a total 30histological sections were obtained for each coating material in each period of time. Histomorphometric analysiswas performed to measure new bone formed ratio between implant and original bone, after 2 and 6 weeks healingperiods.Results: There was increased in new bone formation ratio for the strontium chloride coated implants thanhydroxyapatite coated implants and over the two periods of time. There was an increase in the new bone formationratio at bone-implant interface with time.Conclusion: Coating commercially pure titanium implant with strontium chloride was more efficient in increasingosseointegration at bone implant interface than hydroxyapatite , which was demonstrated by higher new boneformation and maturation at the two periods of time 2 weeks and 6 weeks after implantation


Article
The effect of storage time and disinfection method on the activity of some dental stone disinfectants

Authors: Enas M. Tarik ايناس طارق --- Shatha S. Al-Ameer شذى الامير
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2005 Volume: 17 Issue: 3 Pages: 8-12
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: It has been recommended that all materials returning from the laboratory be disinfected before placement in the patient’s mouth. Various adverse reactions have been reported when using disinfectant solutions with impression materials. Therefore, disinfection of dental cast may be effective in preventing cross infection. This study was carried out to evaluate the effect of storage time on the antimicrobial activity of chlorhexidine, sodium hypochlorite, and madacide-1 solutions and to test the effect of spray, immersion and incorporation techniques on their activities.Materials and Methods: Stone specimens were prepared in cylindrical blocks, under aseptic conditions, containing the three tested solutions applied by spray, immersion and incorporation methods. These specimens were stored for (1½h, 1 day, 3days, 7days, and 10days) and then tested by using disk-diffusion plate method to estimate the release of disinfectant solutions against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa,and Candida albicans. The zones of inhibition were measured with a ruler (in mm) after incubation, which was for 24h at 37°C aerobically.Results: The results showed that all microorganisms were sensitive to chlorhexidine and sodium hypochlorite while E.coli and P. aeruginosa were resistant to madacide. Also it was shown that chlorhexidine was more effective than madacide and sodium hypochlorite as a long acting disinfectant while sodium hypochlorite was the most effective as a short acting one.Conclusion: Immersion method had more inhibitory effect than the other methods representing (60 %) of all the tested specimens followed by incorporation method (25%) and the least percentage for spray method (15%).


Article
The influence of different pH of saliva and thermal cycling on the adaptation of different denture base materials

Authors: Yasir A. Hussein ياسر حسين --- Shatha S. Al-Ameer شذى الامير
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 3 Pages: 47-53
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The difference in the adaptation of denture bases processed from heat cure acrylic, light cure acrylicand nylon materials and the effect of artificial accelerated aging (thermal cycling and pH) on the adaptation wasstudied.Materials and methods: One hundred eighty stone cast were prepared and assigned into 3 main groups accordingto the denture base material that processed on them(heat cure, light cure, nylon), each denture base and its castwas sectioned at posterior palatal border and the gap between the denture base and the cast was measured usingdigital microscope. Half of each group exposed to thermal cycling (2000 cycle) between (5 C-55 C ) 30 second ineach bath then the adaptation was evaluated again. All denture bases were stored in artificial saliva of different pH(5.7, 7,8.3) at 37 C for 30 days, then the adaptation was measured again.Results and discussions: The results showed that the adaptation of heat cure acrylic was better than light cure andnylon before and after aging process. The nylon showed the poorest adaptation. Thermal cycling decreases theadaptation of all denture bases. Variation of pH effected the adaptation of heat cure and light cure denture basesand did not affect the adaptation of nylon


Article
Effect of thermocycling on some mechanical properties of polyamide hypoallergenic denture base material (comparative study)

Authors: Azad M.R. Al-Muthaffer ازاد المظفر --- Shatha S. Al-Ameer شذى الامير
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: special issue 2 Pages: 25-30
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Hypoallergenic denture base material became recently the most attractive option due to their use asalternative to poly methyl methacrylate in hypersensitive patients. The study of the effects of thermocycling on themechanical properties is very important, as it is beneficial for clinical purposes.Materials and methods: One hundred and sixty specimens were prepared according to manufacturer's instructionsand they were divided into two groups: Valplast and Vertex as a control group (eighty specimens for each), twentyspecimens from each material were used to test each of property. They were either thermocycled or notthermocycled (n = 10).Results: There was significant difference between polyamide and conventional heat cured acrylic in the four testedproperties. Furthermore, thermocycling significantly decreased the flexural strength of both polyamide and the heatcured acrylic and it significantly increased the tensile strength and hardness of both tested materials. Thermocyclingdid not significantly affect the impact strength of both materials.Conclusions: Vertex showed higher values of flexural strength than Valplast, flexural strength of both materialsdecreased post-thermocycling. Although the flexural strength of valplast was relatively low, it demonstrated greaterimpact strength than Vertex, impact strength of both tested materials was not affected by thermocycling. The tensilestrength of Vertex was more than Valplast, for both materials tensile strength increased after thermocycling. Thehardness of Vertex was higher than that of Valplast, both materials' hardness increased after thermocycling


Article
The effect of recasting on the Fatigue resistance of Co-Cr alloys

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Abstract

The present study evaluated the effect of recasting cobalt-chromium alloys with the addition of new alloy in different ratios (75% and 50%) on the deflection fatigue resistance using three types of alloys: Wironit (Bego), Remanium (Dentaurum), and Wisil (Wipla). Each alloy was divided into three groups for each test, group I (100% new alloy), group II (75% new alloy +25% recast alloy), and group III (50% new alloy + 50% recast alloy).Fatigue specimens produced were butterfly-shaped and half round at their cross section with 18mm length, 1mm thickness, and 2mm width. For each alloy group, five samples were prepared.The results of this study revealed that recasting with adding 75% new alloy did not significantly affect the fatigue resistance of Wironit and Wisil alloys, while significantly affected that of Remanium. Recasting with the addition of 50% new alloy significantly decreased the fatigue resistance of the three types of alloys.Wironit alloy showed the higher mean values for deflection fatigue resistance compared with Remanium and Wisil alloys.

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