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Öğe Effect of Hemp Fiber Addition on Mechanical Properties of Acrylic Resin: Coupled Experimental and Theoretical Study(Korean Fiber Soc, 2022) Bolayir, Giray; Soygun, Koray; Avsar, Melek Kilic; Boztug, Ali; Kaya, Savas; Katin, Konstantin P.We present experimental and theoretical study of the fiber-matrix composites based on polymethyl methacrylate (PMMA) prosthetic material. Hemp fibers of different lengths and concentrations were added to PMMA. In total, ten groups of composite samples were prepared. Flexural strength test was performed for each sample. We found that the addition of hemp fibber significantly change the mechanical properties of pristine PMMA. The nature of the interaction between PMMA and hemp fiber were further investigated with scanning electronic microscopy, infrared spectrometry and density functional theory. This interaction were described atomistic level in terms of quantum descriptors of reactivity, such as chemical potential, electronegativity, chemical hardness and softness, electrophilicity, electrodonating and electroaccepting powers and electrons transfer. We observed the formations of strong hydrogen bonds between the matrix and fibers, which explain the observed improvement of mechanical properties.Öğe Effect of Maleic Anhydride Pretreatment on Tensile Bond Strength of a Silicone Soft Liner to a Denture Base Polymer(QUINTESSENCE PUBLISHING CO INC, 2011) Demir, Hakan; Soygun, Koray; Dogan, Arife; Keskin, Selda; Dogan, Orhan Murat; Bolayir, GirayPurpose: To determine the effect of resin surface treatment with dissolved maleic anhydride in butanone added into primer on the tensile bond strength between an acrylic denture base resin and a silicone soft liner. Materials and Methods: To test tensile bond strength, standard dumbbell-shaped acrylic specimens were prepared. Five experimental groups, including the control, were tested (n = 5). Maleic anhydride solutions prepared in butanone at concentrations of 1%, 5%, 10% or 20% were then mixed with 1 ml of Primo adhesive and the mixtures were applied onto the resin bonding surfaces. Silicone liner material was applied to resin surfaces in the conventional manner. Tensile bond strength of the specimens was measured in a universal testing machine. Fractured surfaces were observed under the scanning electron microscope, and resulting chemical changes with the solutions used were analyzed spectroscopically. Results: The highest bond strength value was obtained for the group treated with 5% maleic anhydride (2.53 +/- 0.48 MPa); the lowest value was for the group treated with 20% maleic anhydride (1.59 +/- 0.29 MPa). Mixed failure was the dominant type seen in the experimental groups. Spectroscopic analysis showed the interaction of the anhydride carbonyl groups with the Primo primer. Conclusion: The treatment of resin surfaces with maleic anhydride added to Primo adhesive effectively increased bond strength between silicone soft liner and denture base resin.Öğe The Effect of Surface Treatments on Tensile Bond Strength between a Silicone Soft Liner and a Heat-Cured Denture Base Resin(TAYLOR & FRANCIS LTD, 2011) Soygun, Koray; Bolayir, Giray; Dogan, Arife; Demir, Hakan; Dogan, Orhan Murat; Keskin, SeldaThis study evaluated tensile bond strength of a denture soft lining material to a poly (methylmethacrylate) (PMMA) denture base resin subjected to different surface treatment modalities and thermocycling. The materials tested were a silicone-based liner, Molloplast B (R), and a heat-cured denture base resin, Meliodent (TM). The denture soft lining material was packed against cured PMMA base resin, which was smoothed; sandblasted with 250-mu m Al2O3 particles; or lased with a KTP laser; or against uncured PMMA dough (n = 10). In each group, five specimens were thermocycled in a water bath (5-55 degrees C; 3000 cycles) before testing, whereas the other five were directly tested after 24 h. A tensile test was performed using a universal testing machine. Data showed that different treatment modalities of resin surfaces affected adhesion between these two materials and the highest bond values were recorded for cured/smoothed samples under each condition tested. Thermocycling of specimens had no significant reducing effect on measured bond strength values.Öğe Effects of Different Denture Cleansers on the Tensile Bond Strength of Denture Liners(TAYLOR & FRANCIS LTD, 2009) Demir, Hakan; Soygun, Koray; Bolayir, Giray; Dogan, Arife; Keskin, Selda; Dogan, Orhan MuratThe effect of two denture cleansers (Polident (R) and Protefix (R)) on the tensile bond strength between four soft liner materials (Molloplast B (R), Permaflex (R), Sofreliner Tough Medium (R), and GC Reline Soft (R)) and a conventional denture base resin was investigated. For each of the liner materials 35 test specimens were prepared according to test the requirements and assigned into seven groups (n=5). Before tensile testing, five of the liner specimens were kept in water or soaked in two cleansing solutions during 2 and 7 d. Five other samples served as a control group subjected directly to tensile testing. The bond strength values were obtained using a universal testing machine and compared statistically. The type of failure was assessed visually. No significant difference was found between the groups for the tested conditions used (p0.05). The most frequent failure mode was cohesive for Molloplast and Permaflex specimens, adhesive for Sofreliner Tough Medium, and a mixed type of failure was observed for GC Reline Soft material.Öğe Effects of the Different Methacrylate Monomers on Bond Strength Between Soft Liner and Acrylic Resin(ASIAN JOURNAL OF CHEMISTRY, 2013) Bolayir, Giray; Soygun, Koray; Simsek, Selcuk; Yilmaz, Ersen; Dogan, Arife; Boztug, Ali; Dogan, Orhan MuratIn the present study, tensile bond strength between on acrylic resin and a soft liner, molloplast B, was studied. To enhance the bonding capacity between these materials, acrylic resin surface was modified using ethyl methacrylate, iso-butyl methacrylate or tert-butyl methacrylate monomers. The monomers were applied onto the surfaces of methacrylate components for 60, 120 or 180 s and the bond strength values were obtained. The values were statistically compared. Changes on the modified surfaces were investigated by fourier transform infared spectroscopy with attenuated total reflectance (FTIR-ATR). The highest bond strength value was obtained from 120 s treatments with ethyl methacrylate and the lowest value was obtained from 60 s treatments with iso-butyl methacrylate. These high alkyl monomers also had secondary interactions on the acrylic surfaces, evidenced by FTIR-ATR.Öğe Farklı rezin esaslı protez kaide materyallerinin bazı reolojik özelliklerinin araştırılması(Cumhuriyet Üniversitesi, 2009) Soygun, Koray; Bolayır, GirayBu in vitro çalışmanın amacı, 4 mm uzunluğunda estetik 3 farklı fiber ağırlıkça %3 konsantrasyonda rastgele oryantasyonla akrilik protez kaide rezininin güçlendirilmesinin ve akrilik rezine alternatif yüksek tesirli poliamid 6.6 protez kaide rezinlerin, bükülme dayanımının, darbe dayanımının, ısısal ve reolojik özelliklerini araştırmaktır.Protez kaide plağı olarak yaygın kullanılan poli(metil metakrilat) rezin kontrol örneklerine 3 farklı türdeki (E-cam, naylon 6, naylon 6.6) fiberlerin ilave edildiği ve ayrıca geleneksel akrilik protez kaidesine alternatif olan yüksek tesirli poliamid 6.6 esaslı (Valplast) protez kaide rezin örnekleri, test gereksinimlerine göre hazırlanan standart metal kalıplar yardımıyla elde edildi. Bükme testi için örnekler, ADA standart No.12, darbe testi için ASTM D-256 standartlarına uygun olarak hazırlandı. Mekanik test öncesi örnekler, 37 ºC de 24 saat distile su içerisinde bekletildi. Bükme ve darbe dayanım özelliklerini değerlendirmek için, üç nokta eğme (n=7) test cihazı (Lloyd NK5, Lloyd Instruments Ltd, Fareham Hampshire, UK) 5 mm/dakika hız ile uygulandı. Darbe (n=7) test cihazı (Dynatup 9250 HV, Instron, UK), termogravimetrik analiz (Perkinelmer, Diamond TG/TDA, USA) cihazı, termomekanik analiz (Shimadzu TMA 50, Shimadzu, North America) cihazı ile test edildi. Bükülme testi sonrası her bir grup için tipik kırık yüzeyler, taramalı elektron mikroskopla polimer matris/fiber ara yüz bağlantısı için incelendi. Tüm testler oda sıcaklığında yapıldı; elde edilen veriler istatistiksel olarak analiz edildi.Mekanik test sonuçları, yüksek tesirli poliamid 6.6 esaslı protez kaide materyali bükme ve darbe dayanımlarının, kontrol ve fiber eklenen gruplardan daha iyi sonuçlar sağladığını gösterdi.En yüksek bükme ve darbe dayanımları, sırasıyla Valplast ve cam fiber ilave edilen gruplar için elde edildi. SEM analizi ile polimer matris / fiber adezyonu cam fiber eklenen örneklerde görüldü.Termogravimetrik ve termomekanik analiz test sonuçları, ilave edilen fiberlerin polimer matrisle uyumlu olduğu, tüm örnek gruplarının ağız sıcaklığı değişim aralığında ısısal bozunma olmadığı, termomekanik analiz test sonuçlarından elde edilen parametreler de örnek grupların kontrol grubuna göre daha iyi sonuçlar verdiği kaydedildi.Sonuçlar, bu fiberlerin ve alternatif rezinlerin klinikte kullanımları açısından incelenen test yöntemleri dışında daha ileri çalışmalar yapılmasına işaret etmektedir.Anahtar kelimeler: Akrilik rezin, güçlendirme, fiber, yüksek tesirli poliamid 6.6 rezin, mekanik özellikler, termogravimetrik özellikler, termomekanik özellikler.Öğe Investigation of Mechanical and Structural Properties of Blend Lignin-PMMA(HINDAWI PUBLISHING CORPORATION, 2013) Soygun, Koray; Simsek, Selcuk; Yilmaz, Ersen; Bolayir, GirayThis in vitro study investigated the mechanical and structural characteristics of lignin-added PMMA resin composites at concentrations of 1, 3, and 5% by weight. Four sample groups were formed. For the transverse strength test, the specimens were prepared in accordance with ANSI/ADA specification number 12, and for the impact test ASTMD-256 standards were used. With the intent to evaluate the properties of transverse strength, the three-point bending (n = 10) test instrument (Lloyd NK5, Lloyd Instruments Ltd., Fareham, Hampshire, UK) was used at 5 mm/min. A Dynatup 9250 HV (Instron, UK) device was employed for the impact strength measurements (n = 10). All resin samples were tested by using a thermomechanical analyzer (Shimadzu TMA 50, Shimadzu, Japan). Mechanical tests revealed that, although the control group was found to have the value of highest transverse strength, the highest impact strength was observed in the PMMA-L-1 group. Upon examining the thermomechanical analysis data, it could be seen that the E value of the control sample was higher than that of all the other samples. Adding lignin powder into PMMA performs plasticizer effect on resin matrix.Öğe Investigations on the effects of mouthrinses on the colour stability and surface roughness of different dental bioceramics(KOREAN ACAD PROSTHODONTICS, 2017) Soygun, Koray; Varol, Osman; Ozer, Ali; Bolayir, GirayPURPOSE. In this study, three bioceramic materials, [IPS Empress CAD (Ivoclar), IPS e.max CAD (Ivoclar), and Lava Ultimate CAD (3M ESPE)] were treated with three commercial mouthrinses [Listerine, Tantum Verde, and Klorhex]; and changes in colour reflectance and surface roughness values were then quantitatively assessed. MATERIALS AND METHODS. One hundred and twenty ceramic samples, with dimensions of 2 x 12 x 14 mm, were prepared and divided into nine sample groups, except three control samples. The samples were immersed in the mouthrinse solutions for 120 hrs, and changes in colour reflectance and surface roughness values were measured by UV light spectrophotometry (Vita Easyshade; VITA Zahnfabrik) and by profilometer device (MitutoyoSurftest SJ- 301), respectively. The change of surface roughness was inspected by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). RESULTS. There was a positive correlation between the Delta E and increase in the surface roughness. Two of the ceramic materials, IPS Empress and Lava Ultimate, were affected significantly by the treatment of the mouthrinse solutions (P<.05). The most affecting solution was Tantum Verde and the most affected material was Lava Ultimate. As expected, the most resistant material to Delta E and chemical corrosion was IPS e max CAD among the materials used. CONCLUSION. This work implied that mouthrinse with lower alcohol content had less deteriorating effect on colour and on the surface morphology of the bioceramic materials.Öğe Mechanical and thermal properties of polyamide versus reinforced PMMA denture base materials(KOREAN ACAD PROSTHODONTICS, 2013) Soygun, Koray; Bolayir, Giray; Boztug, AliPURPOSE. This in vitro study intended to investigate the mechanical and thermal characteristics of Valplast, and of polymethyl methacrylate denture base resin in which different esthetic fibers (E-glass, nylon 6 or nylon 6.6) were added. MATERIALS AND METHODS. Five groups were formed: control (PMMA), PMMA-E glass, PMMA-nylon 6, PMMA-nylon 6.6 and Valplast resin. For the transverse strength test the specimens were prepared in accordance with ANSI/ADA specification No.12, and for the impact test ASTM D-256 standard were used. With the intent to evaluate the properties of transverse strength, the three-point bending (n=7) test instrument (Lloyd NK5, Lloyd Instruments Ltd, Fareham Hampshire, UK) was used at 5 mm/min. A Dynatup 9250 HV (Instron, UK) device was employed for the impact strength (n=7). All of the resin samples were tested by using thermo-mechanical analysis (Shimadzu TMA 50, Shimadzu, Japan). The data were analyzed by Kruskal-Wallis and Tukey tests for pairwise comparisons of the groups at the 0.05 level of significance. RESULTS. In all mechanical tests, the highest values were observed in Valplast group (transverse strength: 117.22 +/- 37.80 MPa, maximum deflection: 27.55 +/- 1.48 mm, impact strength: 0.76 +/- 0.03 kN). Upon examining the thermo-mechanical analysis data, it was seen that the E value of the control sample was 8.08 MPa, higher than that of the all other samples. CONCLUSION. Although Valplast denture material has good mechanical strength, its elastic modulus is not high enough to meet the standard of PMMA materials.Öğe Peel Bond Strength of Two Silicone Soft Liners to a Heat-cured Denture Base Resin(QUINTESSENCE PUBLISHING CO INC, 2011) Demir, Hakan; Dogan, Arife; Dogan, Orhan Murat; Keskin, Selda; Bolayir, Giray; Soygun, KorayPurpose: This study investigated the peel strength of two different soft liners to a polymethylmethacrylate (PMMA) denture base resin before and after thermocycling. Materials and Methods: The silicone-based soft liner materials tested were Molloplast B and Permaflex; the denture base material was a heat-cured acrylic resin, Meliodent. A total of 40 specimens was prepared using rectangular molds with dimensions of 100 x 10 x 2 mm for PMMA and 150 x 10 x 2 mm for soft liners, as described in ASTM-D903-93. For each of the liner materials, 10 specimens were packed against a cured PMMA denture base surface as recommended by the manufacturers. The other 10 specimens were packed against PMMA denture base dough and processed together. In each group, 5 of the specimens were tested directly, while the other 5 were thermocycled in a water bath (5 C to 55 C; 3000 cycles) before testing. Peel testing was performed using an Instron testing machine. Results: The results revealed that peel strength values of the Permaflex specimens prepared according to the manufacturer's recommendations were significantly higher than those of Molloplast B (p < 0.05). However, when packing was done against uncured PMMA dough, the difference between the specimens of two liners was not significant. Thermocycling led to significant decreases in the peel strength of both Permaflex liner specimens packed against cured/uncured PMMA resin surfaces (p < 0.05), whereas this process did not affect the strength of Molloplast B specimens. Conclusion: Results indicated that the material Molloplast B was superior to the material Permaflex in terms of peel strength when the specimens were simultaneously polymerized with PMMA and thermocycled.Öğe Preparation of complete denture with neutral zone stability: Case report(2010) Soygun, Koray; Demir, Hakan; Bolayir, GirayThe aims of making complete dentures are to repair the functional losses of a patient, provide proper phonation and to improve aesthetics. Ensuring both denture retention and its stability is of paramount importance. Retention depends on the accuracy of the impressions from the patient and the congruence of the denture base with the tissue, and stability relies on tooth position, base flange form, contour of the polished surfaces, and the amount of occlusion. It has been reported in the literature that, muscle functions of the cheek, lips and tongue are major factors for the dentures stability. The stability factors besides occlusion are known to be determined by the procedures in defining the neutral zone. Thus definition of neutral zone is necessary to provide stability in dentures. In our two cases, we present the preparation of complete denture for an edentulous patient.Öğe The surface and phase analysis studies on dental bioceramics subjected to different mouthrinse solutions(SPRINGER, 2018) Ozer, Ali; Soygun, Koray; Bolayir, GirayIn this study, three bioceramic materials, [IPS Empress (R) CAD (Ivoclar), IPS e.max (R) CAD (Ivoclar), and Lava Ultimate (R) CAD (3 M ESPE)] were treated with three commercial mouthrinses [Listerine, Tantum Verde and Klorhex]; and surface phase changes were then assessed. The samples were prepared with dimensions of 2 x 12 x 14 mm. They were immersed in the mouthrinse solutions by using a home-made agitation instrument for 120 h, but for the control group, the rinsing solution was distilled water. Surface phase changes were measured by X-ray diffraction (XRD) device (Bruker AXS D8 Advance, USA), and the change of surface roughness was inspected by scanning electron microscopy (LEO 440 Computer Controlled Digital, UK). XRD patterns of IPS e.max (R) CAD, IPS empress (R) CAD, and Lava Ultimate (R) CAD were evaluated in the study and phases were determined as different mouthwash deterioration then the effects of peak formation was indicated. Phases were seen some differentiation in terms of the crystalline structure. SEM images to investigate the surface roughness of the samples were employed. When the distilled water was applied, the surface was smoother and compact, but the surface of the samples subjected to Tantum Verde, Klorhex, and Listerine showed that the surface was deformed by erosive wear and corrosion of the ingredients. This work implied that mouthrinse with lower alcohol content had less deteriorating effect on the bioceramic materials. In terms of phase and surface roughness change, Lava Ultimate (R) CAD has been effected the most corroded surface among used bioceramics owing to organic content concentration.
