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Article
Removal of mercury contamination from the dental clinic with metal backing for X-ray film

Author: Angham G. AL-Hashimi انغام الهاشمي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2005 Volume: 17 Issue: 2 Pages: 24-27
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Mercury in dental clinic has been recognized as a potential health hazard. This evaluated the removal of Hg spills from different surface in dental clinic with tin in the metal backing for dental x-ray film.Materials and Methods: Hg 90 drops (each one of 0.2 g) placed on 9 different surfaces in the dental clinic, and were divided into: Group I (protective surfaces) subgroup 1 (mask) subgroup 2 (gloves) subgroup 3 (dental apron)Group II (dental instrument and equipment) subgroup 1 (metals, for example, the metal tray of sterilizer) subgroup 2 (dental chair unit) subgroup 3 (wet surfaces, for example, the vacuum suction tank of the sucker). Group III (other clinical surfaces) subgroup 1 (working bench) subgroup 2 (the floor) subgroup 3 (the carpet). The metal backing for x-ray film (0.4 g) placed on each Hg spill, and the time of adsorption was recorded in seconds using a digital timer.Results: The results showed adsorption of Hg spills to the metal backing for x-ray film in all groups except in the crevice of the carpet. Group I subgroup 2 showed the faster interaction (7.1 + 2.828 sec.) while group II subgroup 3 showed the slowest interaction (90.3 + 20.981 sec.).Conclusion: Hg spills on dental protective surfaces can be removed easily, while the most difficult spills to be removed were on the wet surface. Furthermore, Hg spills in crevis of the carpet can not be removed

Keywords

Mercury --- metal backing --- x-ray film


Article
The effect of extending the head length of carbide fissure bur on it's effectiveness in cutting dentin

Author: Angham G. Al-Hashimi انغام الهاشمي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2005 Volume: 17 Issue: 3 Pages: 42-44
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Extending the head length of carbide fissure bur is one of the major trends in bur design. The Aim of study was to evaluate the effectiveness of one of the major trends in bur design which is the extended head length carbide fissure bur, in cutting dentin.Materials and methods: The cutting of extended head length (EHL) and non extended head length (NEHL) carbide fissure burs were evaluated on dentin specimens mounted in acrylic blocks. The specimens were divided into two groups: Group I Cutting performed with NEHL carbide fissure bur (10 burs), Group II Cutting performed with EHL carbide fissure bur (10 burs). Ten cuts were performed with each bur and a total of 200 cutting rates or CRs (mm/sec) were recorded. The CRs were statistically analyzed using analysis of variance (ANOVA) test, least significant difference (LSD) test, and student t-test.Results: A significant difference (P< 0.5) appeared between CRs of group I after cut 7 and in group II after cut 2.Conclusion: Although, extending the head length of carbide fissure bur enhances it's cutting effectiveness, but such a bur is readily dulled during cutting procedure


Article
The shear bond strength of an immediate and delay repaired light-cure composite restoration (In vitro study)

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Abstract

Background: Defects in composite resin restoration whether discovered at the time of placement or associated withold composite resin restoration could be repaired without replacing the entire restoration. This in vitro study wasconducted to determine and compare the shear bond strength of an immediate and delay repaired light curedcomposite restoration.Materials and methods: Eighty acrylic blocks (25x25x15 mm) were constructed from cold cure acrylic resin; each onecontained an acrylic hole (6mm diameter and 3mm depth) that filled with Helioprogress composite resin. The surfacelayer of the composite resin samples was light cured through plastic strip, abraded by finishing discs and rinsed withdeionized distilled water for 15 sec. The eighty specimens were divided randomly into two groups according to thestorage time in deionized distilled water before the repair:Group I: Stored for 15 min. (Immediate repair group)Group II: Stored for 1week. (Delay repair group)Both groups were subdivided into 4 subgroups according to the surface treatment they received:Subgroup 1: No surface treatment (control)Subgroup 2: 37% phosphoric acid etchant (15 sec.)Subgroup 3: Heliobond (light activated for 20 sec.)Subgroup 4: 37% phosphoric acid and Heliobond.Repair was done by using a standardized translucent plastic straw (3mm diameter and 6mm length) and was filledHelioprogress composite resin and light cured for 40 sec. in four directions. All the specimens were stored in deionizeddistilled water for 24 hr. testing was done by the Zwick testing machine by applying shearing force with speciallydesigned chisel-shape rod. Data obtained were statistically analyzed using analysis of variance test and t-test.Results: The results showed very highly significant difference between the similar subgroups in group I vs. group II andthere was non-significant difference between subgroup 1 vs. 2 and between subgroup 3 vs. 4.Conclusion: Delaying the repair procedure for 1 w resulted markedly reduced the bond strength, the surfacetreatment with 37% phosphoric acid slightly reduced the bond strength in the immediate repair while slightlyincreased it in the delay repair, Furthermore, the surface treatment with Heliobond fifth generation bonding agentmarkedly increased the bond strength in both repairs.

Keywords

Repair --- composite --- shear bond

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