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Öğe Ana modelin elde edilmesinde vakumlu kabin tekniği(2015) Akpınar, Yusuf Ziya; Aslan, Muhammed Ali; Tatar, Numan; Yılmaz, BetülAmaç: Bu çalışmanın amacı farklı karıştırma ve döküm tekniklerinin alçının fiziksel özellikleri üzerine etkisini karşılaştırmaktır. Gereç ve Yöntemler: Çalışma planı iki yönlü olarak düzenlenmiştir; farklı karıştırma tekniklerinin alçının fiziksel özellikleri ve kalitesi üzerine etkisini incelemek. Örnekler karıştırma tekniklerine göre dört gruba ayrıldı: El ile karıştırma (Grup H), vakumlu mikser ile karıştırma (Grup VM), vakumlu kabin ile karıştırma (Grup VK), vakumlu mikser ve sonrasında vakumlu kabin kombinasyonu(Grup VM/VK) . Altmış örnek, üç nokta bükülme testi için hazırlandı. Model kırıklıkları kaydedilerek Kruskal-Wallis istatistik testi ile analiz edildi. Alt çene fantom akrilik dişler (Diş No: 43, 42, 41, 31, 32, 33) shoulder basamaklı metal desteksiz seramik veneer kron preparasyonu yapıldı ve ölçü alındı. Ana model üzerindeki poroziteler x40 büyütmeli mikroskop altında incelendi. Sonuçlar analizi için Tek Yönlü Varyans Analiz (α = 0.05) yöntemi kullanıldı. Bulgular: Sonuçlar göster, VM/VK tekniğinin modeldeki poroziteyi anlamlı ölçüde (p < 0.05) azalttığını ve modelin dayanım derecesini arttırdığını göstermiştir. En yüksek dayanım değeri Grup VM/VK' da (31.8 ± 0.7 MPa) oluşurken en az dayanım değeri Grup H' de (20.8 ± 0.1 MPa) oluştu. Sonuç: Vakumlu kabin ve vakumlu mikser tekniği ile kombinasyonu ana model dayanıklılığını arttırır ve poroziteyi azaltır. Bundan dolayı bu teknik ana modellerin dökülmesi için düzenli olarak kullanılabilir.Öğe Effect of bleaching agents on surface texture of feldspathic ceramic(Ondokuz Mayis Universitesi, 2014) Ural, Çağrı; Gençer, Yücel; Tarakçı, Mehmet; Aslan, Muhammed Ali; Arıcı, Selim; Tatar, NumanThe aims of this study were to evaluate the effects of different carbamide peroxide concentrations on surface structure changes of porcelain restorative materials. A total of 50 discs were made and divided into five groups each include 10 specimens. One group served as control and no bleaching agent was applied. Other groups were immersed in the bleaching gels with the concentration of 10% (Group 10), 15% (Group 15), 20% (Group 20), 35% (Group 35) for an average of 8 hours per day. The bleaching procedure was performed over a period of 21 days. The surface roughness values were measured by surface profilometry. Treated ceramic surfaces were examined by scaning electron microscopy (SEM) and atomic force microscopy (AFM). The data were analyzed by analysis of variance and post-hoc Tukey test. The results showed that higher concentration of carbamide peroxide gel effect the surface roughness of test specimens significantly. The highest surface roughness values were obtained in group 35 (0.57 ?m±0.19) and showed significantly different from group C (0.24 ?m±0.11) which was the lowest surface roughness values. The concentration of the carbamide peroxide bleaching agent used in this study affected the surface roughness of the porcelain test specimens. Ceramic restoration should be protected before any bleaching for preventing negative effects of agent on surface properties.Öğe Effect of different denture adhesives on retention of complete dentures: an in vivo study(Taylor & Francis Ltd, 2017) Yeğin, Elif; Akpınar, Yusuf Ziya; Yavuz, Tevfik; Aslan, Muhammed AliThe increase in prevalence of tooth loss with the effect of population aging produces the growing need for complete dentures. The success and acceptance of complete dentures by the patient depends on sufficient retention and stability. Therefore, denture adhesives are regularly used by denture wearers to improve the function of complete denture. We evaluated the effect of three different denture adhesives (Corega, Protefix, Fittydent) on the retention of maxillary complete denture (MCD) using with digital dynamometer (DD). For this purpose, denture adhesives were applied on MCDs of 30 participants. After chewing procedure, the force was applied at 45 degrees to the palatal surface of denture by DD. Dislodgement force was recorded by means of Newton. There were four measurements on each patient including; group of control: Group C; Group CR: Corega; Group F: Fittydent; Group P: Protefix. The result of the study was statistically evaluated by using analysis of variance (ANOVA) and Tukey HSD test. Statistics of ANOVA showed a significant difference among all the four groups (p=0.00, <0.05). Tukey HSD test indicated that there was a statistical difference between Group F and the other groups, but there was not a significant difference between the other groups. The highest adhesive strength value was observed in group F, the lowest in group C. Use of denture adhesives improved the retentive strength of complete denture.Öğe Effect of different surface shapes formed by femtosecond laser on zirconia-resin cement shear bond strength(Taylor & Francis Ltd, 2015) Akpınar, Yusuf Ziya; Yavuz, Tevfik; Aslan, Muhammed Ali; Kepceoğlu, Abdullah; Kılıç, Hamdi ŞükürObjective: The purpose of this study was to evaluate the effect of different surface shapes formed by femtosecond (FS) laser on zirconia (Y-TZP)-resin cement shear bond strength (SBS). Background data: All ceramic restoration is used as an alternative to metal-ceramic restorations, due to its better aesthetics, strength, and toughness properties. However, bond strength of restoration to tooth and other materials is effective to long term success of the restoration, and to achieve it surface treatment is required on ceramic surface. Materials and methods: Forty square-shaped zirconia samples were prepared and assigned to four groups of 10. The details of the groups are as follows: Group A, square-shaped recessed surface; Group B, square-shaped projection surface; Group C, circular-shaped recessed surface; Group D, circular-shaped projection surface. The SBSs values were performed with a universal testing machine at a crosshead speed of 1mm/min. The data were analyzed statistically using analysis of variance (ANOVA) and Tukey HSD multiple comparisons tests. Results: The one-way ANOVA results on SBSs of the zirconia material bonded with resin cement revealed significant differences among the groups (p<0.05). The Tukey HSD test results revealed that Group B and D had significantly higher SBS values than other groups (p<0.05), but there were no significant differences between each other (p>0.05). Additionally, Group A and C had significantly lower values than other groups (p<0.05). Conclusions: Different surface shapes formed by FS laser provided a significant increase in SBSs. The SBS values of projection surfaces of circular and square-shapes are greater than that of recessed surfaces of circular and square-shapes.Öğe Effect of femtosecond laser beam angle on bond strength of zirconia-resin cement(Springer London Ltd, 2015) Akpınar, Yusuf Ziya; Kepçeoğlu, Abdullah; Yavuz, Tevfik; Aslan, Muhammed Ali; Demirtağ, ZülfikarYttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic is widely used as an all-ceramic core material because of its enhanced mechanical and aesthetic properties. The bond strength of Y-TZP restorations affects long-term success; hence, surface treatment is required on ceramic boundaries. This study evaluated the effect of different laser beam angles on Y-TZP-resin cement shear bond strength (SBS). Forty plates of Y-TZP ceramics were randomly assigned to four groups (n = 10). A femtosecond amplifier laser pulse was applied on Y-TZP surface with different incidence angles (90A degrees, 75A degrees, 60A degrees, 45A degrees). The resin cement was adhered onto the zirconia surfaces. The SBS of each sample was measured using universal testing machine at crosshead speed of 1 mm/min. The SBS was analyzed through one-way analysis of variance (ANOVA)/Tukey tests. The results showed that the degree of laser beam angle affects the SBS of resin cement to Y-TZP. The laser beam was applied to a surface with a 45A degrees angle which resulted in significantly higher SBS (18.2 A +/- 1.43 MPa) than other groups (at 90A degrees angulation (10.79 A +/- 1.8 MPa), at 75A degrees (13.48 A +/- 1.2 MPa) and at 60A degrees (15.85 A +/- 0.81 MPa); p < 0.001). This study shows that decreasing of the angle between the ceramic surface and the laser beam increased the SBS between the resin cement and the ceramic material, as well as the orifice.Öğe Effect of femtosecond laser treatment on the shear bond strength of a metal bracket to prepared porcelain surface(Mary Ann Liebert, Inc, 2015) Akpınar, Yusuf Ziya; Irgın, Celal; Yavuz, Tevfik; Aslan, Muhammed Ali; Kılıç, Hamdi Şükür; Üşümez, AslıhanObjective: The aim of this study was to investigate the effects of femtosecond laser treatment (Group FS) on the shear bond strength (SBS) of a metal bracket to prepared porcelain surface, and to compare it with other surface treatment techniques [50 mu m Al2O3 sandblasting (Group SB), 9.6% hydrofluoric acid gel (Group HF), and neodymium-doped yttrium aluminium garnet (Nd:YAG laser) (Group NY)]. Background data: Because of the increasing number of adult patients in current orthodontic practice, achieving sufficient bond strength of composite resin to porcelain restorations without bond failure during the treatment is a challenge for orthodontists. Methods: In total, 80 glazed feldspathic porcelain samples were prepared and randomly assigned to four groups of 20. Treated surfaces were treated with a silane agent. Brackets were bonded to porcelain samples. The specimens were stored in distilled water for 24 h and then thermocycled for 500 cycles between 5 degrees and 55 degrees C. The SBS of the brackets was tested with a universal testing machine at a crosshead speed of 1 mm/min, until bonding failure occurred. The data were analyzed statistically using analysis of variance (ANOVA) and Tamhane multiple comparisons tests. The results of ANOVA indicated that the SBS values varied according to the surface treatment method (p<0.001). Results: Results of the Tamhane post-hoc tests indicated that the bond strength in Group NY (5.11 +/- 1.53) was significantly lower than the other groups (p<0.05). There were no statistically significant differences among Groups SB (9.07 +/- 3.76), HF (9.09 +/- 3.51), and FS (11.58 +/- 4.16) (p=0.28). Conclusions: The results of this study showed that FS treatment produced high SBS of the processes assessed; therefore, it appears to be an effective method for bonding orthodontic metal brackets to prepared porcelain surfaces.Öğe Investigation of the effect of titanium alloy surface coating with different techniques on titanium-porcelain bonding(Mosby-Elsevier, 2016) Aslan, Muhammed Ali; Ural, Çağrı; Arıcı, SelimStatement of Problem. The bond strength of dental porcelain to titanium is inadequate as a clinical alternative to conventional alloys for metal ceramic restorations. Purpose. The purpose of this in vitro study was to evaluate the effects of coating titanium surface with a micro-arc oxidation (MAO) technique and hydroxyapatite (HA) on the bond strength of porcelain to titanium surfaces. Material and methods. One hundred twenty machined titanium specimens with a dimension of 25x3x0.5 mm were prepared from grade 5 titanium as the metal substrate. Specimens were divided into 6 groups (n=20) according to the surface treatment used: airborne-particle abraded (control), coated with MAO for 5 minutes, coated with MAO for 15 minutes, coated with MAO for 30 minutes, coated with HA, and combination of MAO and HA. Each group was further divided into 2 subgroups (n=10) according to the type of porcelain used: Noritake Ti-22 porcelain or Vita-Titankeramik porcelain. The bond strength was tested with a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically with 2-way ANOVA and Tukey honest significant differences multiple comparison tests (alpha=.05). Results. For both porcelain groups, the 30-minute MAO groups showed higher bond strength values than those of the control groups (P<.05). In the Vita Titankeramik porcelain subgroup, the specimens coated with HA- did not show any statistical differences compared with those of the control group (P>.05). Surface roughness was affected significantly (P<.001) by the coating procedure compared to that of the the control group. Conclusions. Coating with either MAO or HA improved titanium-porcelain adhesion.
