research centers


Search results: Found 10

Listing 1 - 10 of 10
Sort by

Article
Radiopacity of modified microhybrid composite resin: (An in vitro study)

Authors: Sazan Sh. Saleem سازان سليم --- Salem A. Al-Samarai سالم السامرائي --- Dara H. Saeed دارا سعيد
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: special issue 1 Pages: 18-22
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: The aim of this study was to measure the radiopacity (RO) of modified microhybrid composite resins byadding 2 types of nanofillers (Zinc Oxide and Calcium Carbonate) in two concentrations 3% and 5% and comparingthem to unmodified microhybrid composite resins and to nanofilled composite resin.Materials and Methods: Two types of composite resin were used (Microhybrid composite MH Quadrent anterior shineand Nanofilled composite resin Filtek Z350 XT), for each tested group five disk-shaped specimens (1-mm-thick and 15mm diameter) were fabricated. The material samples were radiographed together with the aluminum step wedge.The density of the specimens was determined with a transmission densitometer and was expressed in term ofequivalent thickness of aluminum. Data analyzed by one-way ANOVA.Results: The radiopacity (RO) values of the tested group ranged between (0.9293- 2.6242 Eq. Al thickness) and therewere significant differences among them. Nanofilled composite resin Filtek Z350 XT showed the highest value of ROwhile unmodified Microhybrid composite MH Quadrent anterior shine showed the lowest value of RO.Conclusion: The addition of 3% of both the ZnO and CaCO3 nanofillers fillers to microhybrid composite significantlyincreased the RO, while the addition of 5% of CaCO3 and ZnO nanofillers to microhybrid composite showed nonsignificantincrease in the RO of the composite.


Article
Effect of curing modes on the depth of cure of resin composite

Author: Abdul–Adheem R Al–Mallah
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2007 Volume: 7 Issue: 2 Pages: 195-200
Publisher: Mosul University جامعة الموصل

Loading...
Loading...
Abstract

Aims: To study the effect of different curing modes of Light emitting diodes (LED) curing unit on thedepth of cure (DOC) of composite resin with light and dark shades and compare the results withconventional curing method by the use of halogen curing light. Materials and Methods: A total of 40cylindrical composite resin samples (4mm diameter and 6mm height) were prepared, 20 of light shadeand 20 of dark shade. They were subjected to four curing modes (n=5 for each group): conventionalhalogen light, and three modes related to the LED light curing unit (LCU) which were: Fast (F); Ramped(R); and Pulsed (P). The samples were irradiated to the time required by the manufacturer for each curingmode, and a digital micrometer was used to measure the depth of cure according to scraping methoddescribed in ISO 4049:2000. Data were collected and analyzed for comparison. Results: No significantdifference was found in the DOC of composite irradiated by LED curing light for all of the three curingmodes or shade. However, the LED produced significantly greater depths of cure when compared withconventional halogen curing unit for both shades. The lighter shade was cured to a significantly greaterdepth than dark one when considering halogen LCU. Conclusions: All curing modes of the LED lightcan produce similar DOC regardless of composite shade when irradiated to the time recommended by themanufacturer. However, Curing with conventional halogen curing unit yielded the least DOC values forlight or dark shades when compared with LED units. Longer irradiation times are needed to cure darkshades by the use of halogen LCUs.


Article
The Effect of Various Bur Types, Bond-ing Agents, and Composite Types on The Microleakage of Resin Composites

Author: Raghad A Al-Askry
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2010 Volume: 10 Issue: 1 Pages: 176-185
Publisher: Mosul University جامعة الموصل

Loading...
Loading...
Abstract

Aims: This in vitro study was conducted to investigate the effect of various bur types, bonding agents, and resin composite restorative materials on the microleakage at occlusal and gingival tooth/composite interfaces. Materials and methods: One hundred and sixty non carious, extracted human premolars were mounted in acrylic resin, the teeth were randomly divided into four groups (n=40) according to the bur types (diamond round bur, diamond fissure bur, carbide round bur, and carbide fissure bur). A standardize class V (3×2×2) mm dimensions cavity was prepared on the facial surface of each tooth (each group with corresponding bur type), then each group was divided into two subgroups (n=20) ac-cording to the type of adhesive systems used (P&B NT,& I-Bond), after that each subgroup farther divided in to two subgroups (n=10) according to the type of composite restorative materials (Arabesk & Tg) the final number of groups were (16) of (10) teeth in each. After the specimens were finished they stored for one month in 37ºc distilled water, thermo cycled for 500 cycles between (5ºc & 55ºc) and immersed in 0.5% methylene blue solution for 24h., and then sectioned longitudinally. For both occlusal and gingival margins, dye penetration at the tooth/composite interfaces were scored from 0-3 under stereomicroscope at a magnification x10, data were analyzed using unpaired T-test, ANOVA, and Duncan’s multiple rang test at 5% significant level. Results: T-test represent that there was less microleakage at occlusal margins than the gingival margins. ANOVA and Duncan’s multiple rang tests show that the less leakage was occurred with the use of carbide fissure bur at both occlusal and gingiv-al margins while the diamond round bur show the highest leakage at both margins. P&B NT show less leakage than I-Bond at the occlusal margin but there was no significant difference between P&B NT & I-Bond at the gingival margins also there was no significant difference between the ( Arabesk & Tg ) restorations at both occlusal and gingival margins. Conclusions: Within the limitations of this study results show that there was less microleakage at the occlusal margin than that at the gingival margins, and the use of carbide fissure bur to prepare the cavities for receiving resin composite materials show the least microleakage than other type of burs, and although phosphoric acid has been intensely used to etch the dental substrates (enamel and dentin) for providing a good bonding, self-etching adhesives can be considered an alternative methods to provided a good bonding for restorative procedures


Article
Fracture Resistance of Premolars with Different Filling Techniques

Author: Ammar Kh Al–Nori
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2007 Volume: 7 Issue: 3 Pages: S103-S108
Publisher: Mosul University جامعة الموصل

Loading...
Loading...
Abstract

Aims: To evaluate the fracture resistance of premolars with mesio–occluso–distal (MOD) preparations with resin composite using different incremental techniques when submitted to occlusal load. Materials and Methods: Fifty premolars were used and randomly divided into five groups of ten teeth each. The teeth in group I were prepared and not restored. The teeth in group II were restored in vertical technique. Teeth in group III were restored in horizontal technique. Teeth in group IV were restored in oblique technique. Teeth in groups II, III and IV were restored using Exite adhesive system and Tetric hybrid composite. Teeth in group V were restored in horizontal technique using combinations of Tetric flowable composite and Tetric hybrid composite. After thermocycling, the teeth were tested under universal compression machine. The data obtained in this research were subjected to analysis of variance and Duncan’s Multiple Range Test. Results: Both groups V and IV significantly increase the fracture resistance of teeth over groups II and III. Conclusions: Selection and appropriate use of materials, better placement technique and control polymerization shrinkage may increase the resistance of teeth to fracture with Class II resin composite restorations.


Article
Fluoride release from different tooth colored restorative materials: An in vitro study

Authors: Manal A AL-TAEE --- Abdul-haq A SULIMAN
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2001 Volume: 1 Issue: 3 Pages: S215-S228
Publisher: Mosul University جامعة الموصل

Loading...
Loading...
Abstract

This in vitro study evaluated the amount of fluoride released from fluoride-containing materials over a period of (30) days. Twenty eight disk samples (2.5 mm depth × 10 mm diameter) were prepared and divided into four groups: GroupI Vitremer glass ionomer, group II resin composite Tetric, group III resin composite Definite, and group IV Compoglass.The samples were stored in an incubator at 37°C for (24) hours. Each disk was suspended in an individual plastic tube containing (3) ml of deionized water. The water was changed every (24) hours, fluoride release was determined at each day for (30) days, after buffering the solution with equal volume of TISAB. The fluoride release was measured with a fluoride-ion selective specific electrode previously calibrated from (0.05) to (100) ppm. Fluoride release was expressed in part per million (ppm).ANOVA test was used to evaluate the data. The results revealed that Vetrimer glass ionomer released significantly more fluoride (4l ppm) for the first day than all the other products. This was followed by Compoglass which exhibits more fluoride release than the other two types (32 ppm), the Tetric composite resin Was the third material in the amount of fluoride released (3.75 ppm), and finally the resin composite Definite released fluoride in about (0.75 ppm). All fluoride release was decreased from day (1) to (30) observation period.


Article
Effect of triammonium orthophosphate on fire retardationof Epoxy resin reinforced with wood flour
تأثير ثلاثي أمونيوم أورثو فوسفات على مقاومة الاحتراق لراتنج الايبوكسي المسلح بنشارة الخشب

Authors: Mohammed. H. Mokhilif محمد هلول مخيلف --- Harith. I. Jaffer حارث ابراهيم جعفر
Journal: Baghdad Science Journal مجلة بغداد للعلوم ISSN: 20788665 24117986 Year: 2011 Volume: 8 Issue: 2عدد خاص بمؤتمر الفيزياء Pages: 671-675
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Epoxy resin reinforced by 30% of wood flour was prepared as a composite . Triammonium orthophosphate as a flame retardant was added to composite at weight percentages of ( 0 , 2 , 3 , 5 , 7 , and 10 ) % . Hand lay-up technique was used to prepare sheets from that composite. The results indicated that the rate of burning decreases with increasing the weight percentage of that flame retardant. And the limiting oxygen Index (LOI ) increases with increasing concentration of that flame retardant .

تم دراسة تأثير اضافة ثلاثي أمونيوم اورثو فوسفات على لهوبية راتنج الايبوكسي المسلح بـ 30% من نشارة الخشب . استخدم المضاف بنسب مئوية ( 0 , 2 , 3 , 5 , 7 , 10 ) % . ثم حضر صفائح من المتراكب بالطريقة اليدوية لصب مكبوسات . قد اظهرت النتائج ان معدل احتراق العينات يتناقض مع زيادة النسب المئوية للمضاف وان معامل الاوكسجين المحدد (LOI ) يزداد مع زيادة تركيز المضاف .


Article
Effectiveness of Four Different Light-activated Composites Cure with Different Light Energy Densities

Author: Dr. Ali A. Al- Shekhli B.D.S., M.Sc., Ph.D.* د. علي الشيخلي
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2006 Volume: 3 Issue: 3 Pages: 224-229
Publisher: Al-Mustansyriah University الجامعة المستنصرية

Loading...
Loading...
Abstract

Background: This study investigated the influence of light energy density (intensityx time) on the effectiveness of composite cure in view of the curing profiles of lightpolymerizationunits with different light- activated composites to determine theenergy density that satisfies adequate polymerization of all light-activatedcomposites types used in this study.Materials and methods: This study investigated the hardness of the top/bottomsurfaces and hardness ratio of 2-mm thick composite specimens after exposure todifferent light energy densities. Parameters included five light intensities (200, 300,400, 500 and 600 mW/cm2) and seven curing times (20, 40, 60, 90, 120, 150 and180 seconds) for each of the four different light-activated composite materials(Tetric Ceram, Heliomolar, Herculite XRV and Degufill Mineral).Results: Statistical analysis of the data by using the one-way analysis of variancerevealed that, most of the hardness ratios exhibited a very highly significantdifference according to intensity, composite type and curing time. The resultsindicated that, Heliomolar and Degufill Mineral light-activated composites requiredapproximately (36 J/cm²) energy density for adequate polymerization for a 2-mmthick specimen while, Herculite XRV and Tertric Ceram light-activated compositesrequired approximately (12 J/cm²) energy density for adequate polymerization for a2-mm thick specimen.Conclusion: This study indicated that, final curing should not be done with energydensity less than (300 mW/cm2 for 120 seconds, 400 mW/cm2 for 90 seconds and600 mW/cm2 for 60 seconds) for Heliomolar and Degufill Mineral light-activatedcomposites.


Article
Tensile Bond Strength of Resin Composite to Er,Cr:YSGG Lased Dentin Bonded With Different Adhesive Systems

Authors: Ula A. Fathi --- Ma,an M. Nayif
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2015 Volume: 15 Issue: 2 Pages: 456-462
Publisher: Mosul University جامعة الموصل

Loading...
Loading...
Abstract

Aims: Tensile bond is important for assessing the success of adhesive restorative materials. The aim of this study is to evaluate the tensile bond strength of resin composite restoration to Er,Cr:YSGG lased dentin bonded with three types of adhesive systems. MATERIALS AND METHODS: Occlusal enamel of eighteen molars samples was removed to expose the underlining dentine. Er,Cr:YSGG laser irradiation was performed to central dentin. Samples were assigned randomly to three groups (N = 6): Group Ι: dentin was treated total etch adhesive (Adper single bond, 3M ESPE); Group II: treated with all in one self—etch adhesive (Adper easy one, 3M ESPE); Group III: treated with two step self—etch adhesive (Clearfil SE bond, Kurary). A translucent plastic tube was fixed and filled incrementally with hybrid resin then small metal screw with ring head was embedded in last increment. Samples were stored in distilled water at 37°C for 24 hours. Tensile bond strength was measuredd using universal testing machine (Digital Force Gauge IMADA CO., LTD, Japan), the failure mode was evaluated. Then statistical analysis was done include descriptive, one way analysis of variance test, and Post Hoc tests. RESULTS: A significant differences in tensile bond strength were observed among groups (p < 0.05). Total etch adhesive bonded demonstrate significantly higher tensile bond strength value than one step self–etch and two step self–etch adhesives (p < 0.05). No significant differences were observed between one step self–etch and two step self–etch adhesives (P>0.05). CONCLUSION: The tensile bond strength of resin composite to Er,Cr:YSGG lased dentin was influenced by adhesive type. Total etch adhesive bonded had higher tensile bond strength than one step and two steps self–etch adhesives.


Article
The Influence of Composite Type and Shade Selection on Depth of Cure of Light-activated Composites

Author: Isra’a A. Al- Aubi B.D.S., M.Sc.* د. اسراء العبيدي
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2006 Volume: 3 Issue: 2 Pages: 117-121
Publisher: Al-Mustansyriah University الجامعة المستنصرية

Loading...
Loading...
Abstract

AbstractBackground: This study investigated the influence of composite type and shade ondepth of cure of light- activated composites.Materials and methods: This study investigated the depth of cure of two compositematerials using two different shades. Parameters included two shades (A1 and C3) oftwo different light-activated composites(Helio Progress and King Dental) cured for 40seconds.Results: Statistical analysis of the data by using the one-way analysis of variancerevealed that, both composite type and shade significantly affect composite depth ofcure.Conclusion: This study indicated that, Although, both composite type and shade weresignificantly affect depth of cure but the effect of composite type on composite depthof cure is much more than that of composite shade.


Article
Evaluationof Curing Depth of Bulk-Fill Resin Composite (A comparative study)

Authors: Salam A. Al-Araji --- Mohammed A. Ibrahim --- Hala A. Ragab
Journal: Medical Journal of Babylon مجلة بابل الطبية ISSN: 1812156X 23126760 Year: 2015 Volume: 12 Issue: 1 Pages: 310-316
Publisher: Babylon University جامعة بابل

Loading...
Loading...
Abstract

This study evaluated the depth of cure (DOC) of recently introduced resin composites for posterior use, bulk filled flowable composite (SureFil® SDR® flow DENTSPLY Caulk) at different depth. 30 specimens were prepared and divided into two Groups,Group 1: specimens with 2 mm depth, Group 2: specimens with 4mm depth. The composite specimens were prepared by using molds of different depth, one of them with was a hole of 4 mm depth and 4 mm internal diameter and the other was with a depth of 2 mm at the same diameter. The hole was bulk filled with SDR flowable composite resin and light cured for 20 seconds with a modern high-intensity LED curing unit (Elipar™ S10, 3M.US.), followed by 24 hours storage in complete darkness incubator at 37 C◦. The degree of conversion was measured on the top and the bottom for both depths using Fourier transform infrared (FTIR) spectroscopy. A bulk filled flowable (SDR)revealed a significant difference in degree of conversion (DOC) when the bottom surface of the specimen witha 2mm depth (DOC=76.27112163) wascompared with the bottom surface of the 4mm depth specimen (DOC=73.92160935). The 2mm depth wasshown statistically significantly higher mean values degree of conversion than 4 mm depth (P-value = 0.032). There was no statistically significant difference in the degree of conversion mean values between the top and the bottom surfaces of the specimen of the same group (P >0.05).Upon the result of thisin vitro study, it was found that the degree of conversion of the SDR bulk-fill flowable resin compositewasaffected by depths. As the depth of the resin compositewas increased the degree of conversion was decreased.

Listing 1 - 10 of 10
Sort by
Narrow your search

Resource type

article (10)


Language

English (10)


Year
From To Submit

2015 (2)

2013 (1)

2011 (1)

2010 (1)

2007 (2)

More...