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Article
Shear bond strength of different lingual buttons bonded to wet and dry enamel surfaces with resin modified glass ionomer cement (in vitro comparative study)

Authors: Hiba M. Alkhateeb هبة محمد الخطيب --- Eman I. Al-Sheakli ايمان الشيخلي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: 1 Pages: 146-152
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: This study was aimed to investigate the effect of three lingual button (Nickel free / rectangular base,Nickel free / round base and Composite) and bonding environment, wet and dry enamel surface, on: the shearbond strength (SBS) of light and self-cured Resin Modified Glass Ionomer Cements, and the debonding failure sites.Materials and method: One hundred twenty no-carious, free of cracks maxillary first premolar teeth were selected.Three types of orthodontic lingual buttons were used in this study: Nickel free / rectangular base, Nickel free / roundbase and Composite buttons. The teeth were divided into two groups of sixty teeth each. One group was used fortesting the chemically cured GC Fuji Ortho Resin modified Glass Ionomer (RMGIC), while the other was used fortesting the light cured GC Fuji Ortho LC RMGIC. Each was further subdivided into two subgroup; thirty teeth werebonded to wet enamel surface while the other was bonded after drying the enamel surface. Then each ten teethfrom each subgroup were bonded with only one type of buttons. The sample was tested for bond strength using theuniversal testing machine and the Adhesive Remnant Index (ARI) was inspected under the stereomicroscope.Results:The highest (SBS) values were obtained in the Nickel free / round base button with both types of RMGIC in wetand dry environment as revealed by ANOVA test. While t-test revealed that both systems of RMGIC yield relativelylower values of (SBS).Conclusions:The GC Fuji Ortho RMGICs resist shear force in dry better that in wet environment.Nickel free / roundbase buttons give the greatest shear bond strength among the three types of button.The composite buttons givegreater bond strength in dry than in wet environment with both GC Fuji Ortho and GC Fuji Ortho LC RMGICs


Article
The effect of thermocycling and debonding time on the shear bond strength of different orthodontic brackets bonded with light-emitting diode adhesive (In vitro study)

Author: Harraa S. Mohammed-Salih حراء صباح محمد صالح
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: 1 Pages: 139-145
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Thermocycling simulates the temperature dynamics in the oral environment. This in vitro study done tomeasure and compare the effect of thermocycling on the shear bond strength of stainless steel and sapphirebrackets bonded to human enamel teeth using light cured orthodontic adhesive and debonded at various time,and to measure adhesive remnant index after debonding.Materials and Methods: one-hundred-twenty extracted upper first premolars for orthodontic reason were used in thisstudy; depending on weather thermocycled or not, the sample was divided into two main groups, then within eachgroup 30 teeth were used for stainless-steel brackets (Bionic®) and for sapphire brackets (Pure®). Both groups weresubdivided into three groups (n = 10) according to the debond times: I: debond after 24 hour, II: debond after 7 daysand III: debond after 30 days. Within 24 hr, half of the sample was thermocycled manually for 500 complete cyclesbetween 5/55°C and the remaining sample was stored in distilled water at room temperature and water waschanged daily until debond time for each group was performed. The adhesive remnant index was tested under 20Xmagnification lens using stereomicroscope.Results and Conclusions: Both bracket types demonstrated high shear bond strength values before thermocycling(P≤0.05), whereas after 500 thermocycles, there were significant changes in shear bond strength resulted in markedreduction in the stainless steel brackets than in the sapphire brackets (P≤0.05). Shear bond strength values increasedwith time for both stainless steel and sapphire brackets with and without thermocycling (P≤0.05). The tendency ofbond failure was increased at the bracket/adhesive interface rather than enamel/bracket interface in the stainlesssteel brackets whereas at the enamel/bracket interface rather than bracket/adhesive interface in the sapphirebrackets.


Article
Effect of plasma treatment of acrylic denture teeth and thermocycling on the bonding strength to heat cured acrylic denture base material

Author: Hikmat J. Aljudy حكمت جميل الجودي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: special issue 1 Pages: 6-11
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Acrylic resin polymer s used in prosthodontic treatment as a denture base material for several decades.Separation and debonding of artificial teeth from denture bases present a laboratory and clinical problem affectpatient and dentist. The aim of this study is to evaluate the effect of oxygen plasma and argon plasma treatment ofacrylic teeth and thermocycling on bonding strength to hot cured acrylic resin denture base material.Materials and Methods: Sixty denture teeth (right maxillary central incisor) are selected. The denture teeth are waxedonto the beveled surface of rectangular wax block according to Japanese standard for artificial teeth. The controlgroup consisted of 20 denture teeth specimen without any treatment. The oxygen plasma group consisted of 20denture teeth specimen treated with oxygen plasma for two minutes exposure time at plasma apparatus. The argonplasma group consisted of 20 denture teeth treated with argon plasma for two minuets exposure time. All thespecimens are undergone flasking and wax elimination procedure in the conventional way. All specimens stored indistilled water for 7 days at 37°C, then half of the specimens of all groups undergoes thermocycling between 5°C -55°C in 60 seconds cycles for three days and tested for shear bond strength using universal testing machine the datawas collected and analyzed statistically using analysis of variance and independent sample t-test.Results: The plasma treated groups showed the higher mean force required to fracture the acrylic teeth from theirheat cured acrylic resin denture bases, as compared to control group, and the oxygen plasma treatment groupshowed higher shear bond value than the argon plasma treatment. The thermocycling had a deleterious effect onbonding strength for control group while the plasma treated group showed an increase in bond strength followingthermocycling.Conclusion: Plasma treatment method was an effective approach for increasing the shear bond strength as a resultof surface oxidation and chemical etching effect of oxygen plasma and micromechanical interlocking effect ofargon plasma


Article
Bond Strength of Endodontic Sealers to Gutta Percha and Dentin

Authors: Raghad A Al-Askary --- Sabah A Ismail --- Nawal A Al-Sabawi
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 2 Pages: 282-289
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: The aims of present study were to compare shear bond strength (SBS) and push-out bond strength (PBS) of three types of sealers to gutta percha (G) and dentin (D) and to assess failure modes at debonded interfaces. Materials and Methods: Sealers tested were AH Plus, Sealer 26, and Endofill. In PBS, 30 mandibular premolar decoronated and instrumented with rotary ProTaper to F3 then teeth were divided into 3 groups (10 teeth in each) and obturated with F3 proTaper G and one of tested sealer, 1mm mid root slices were prepared for PBS test. In SBS/D, 30 root cylinders 7 mm length were embedded horizontally in resin then root surfaces were flattened and smooth. In SBS/G, 30 G cylinders were embedded in a resin. In both SBS tests, specimens were divided into three groups, 10 samples each then polyethylene tubes positioned on polished specimens (prepared for SBS/D and SBS/G) filled with one of the tested sealer. All BS tests were performed on digital universal testing machine. Collected data analyzed statistically using one way ANOVA and Tukey test. Results: PBS, SBS/D, and SBS/G for AH Plus significantly higher than Sealer 26 and Endofill. Also Sealer 26 exhibited significantly higher bond strength than Endofill. Predominance mode of failures were adhesive and mixed. Conclusions: According to the finding of present study, it can be concluded that the AH Plus for root canal therapy produce better results in endodontic. PBS and SBS were sufficient tests to measure bond strength of root canal sealers to G and D.


Article
Effect of different acids surface treatments and thermocycling on shear bond strength of composite resin to feldspathic ceramic

Author: Ammar A. Lateef عمار لطيف
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: 1 Pages: 27-33
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: the aim of this study was to evaluate the effect of different surface acids treatments (37%phospjoricacid, 5%hydrofluoric acid, 1.23 acidulated phosphate fluoride) of feldspathic ceramic VITA 3D MASTER , and theeffect of thermocycling on shear bond strength using a ceramic repair kit (ivoclar/vivadent).Material and Methods: sixty Nickel-Chromium metal base plates were prepared(9mm diameter,3mm depth) usinglost wax technique, 2mm thick layer of ceramic(VITA 3D MASTER) fused to metal plates, all specimens wereembedded in acrylic resin blocks except their examined surfaces and divided into 3 main groups 20 specimenseach, Grp A: treatment with 37%phosphoric acid for 2 mins, Grp B: etching with 5% hydrofluoric acid for 2mins, GrpC: etching with 1.23% acidulated phosphate fluoride for 10 mins; monobond-plus, heliobond, resin composite(TetricEvoCeram) were applied to each specimen according to manufacturer's instruction using transparent splitmold(5mm diameter, 4 mm height); specimens were stored in 37OC distilled water for 12 weeks, 10 specimens ofeach group were subjected to thermocycling between 5 oC and 55 o C for 800 cycles with 30s dwell time; shearbond strength was determined by a universal testing machine (instron 1122) at a cross head speed 0.5mm/min; Oneway ANOVA test, LSD test and student-t test were used to analyze shear bond strength.Results: Mean shear bond strength values for the tested groups were: A1= 11.65±0.68 Mpa, A2=10.88±0.58 Mpa,B1=17.93±0.41 Mpa, B2=17.42±0.35 Mpa, C1=15.17±0.61 Mpa, C2=14.51±0.48 Mpa ; one way ANOVA test showedhighly significant difference among groups; LSD test revealed that the use of 5% HF for ceramic surfacetreatment(GB) was highly significant than the treatment with 37%PA(GA) or 1.23%APF(GC) respectively and the useof 1.23%APF(GC) was highly significant than the use of 37%PA(GA); Student t- test showed a significant differencebetween subgroups of the same group with and without thermocycling.Conclusion: ceramic surface treated with 5% HF acid for 2 mins recorded the highest shear bond strength, followedby surface treatment with 1.23% APF for 10 mins, most specimens treated with 5%HF showed cohesive failure with inceramic while specimens treated with 1.23%AFP showed more (adhesive/cohesive) failure than adhesive orcohesive alone, and specimens treated with 37% PA showed nearly 50:50 adhesive and combination failure,thermocycling reduced the bond strength of each group significantly.

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