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Öğe A study on the discoloration of different dental porcelain systems(Istanbul Univ Press, Istanbul Univ Rectorate, 2023) Ulucan, Mehmet Cagatay; Avsar, Melek Kilic; Bolayir, GirayPurposeThis study aimed to investigate the discoloration of four types of dental porcelain systems (feldspathic, monolithic zirconia, lithium disilicate, and leucite glass -ceramic) with various surface treatments (glazed and mechanically polished) after undergoing chewing simulation against a natural tooth antagonist.Materials and Methods Disc-shaped porcelain groups (9x3mm) were produced for the following categories: feldspathic glazed (FG), feldspathic mechanically polished (FM), zirconia glazed (ZG), zirconia mechanically polished (ZM), lithium disilicate glazed (ExG), lithium disilicate mechanically polished (ExM), leucite glass-ceramic glazed (EG), and leucite glass-ceramic (EM). In vitro chewing simulation was conducted on all porcelain groups, and a spectrophotometer was used to compare the color changes between their initial states. Results The Delta E values (discoloration) of all porcelain samples were statistically different (p<0.05), and the Delta E values of the glazed samples were higher than those of the mechanically polished samples. ConclusionAll the glazed samples are more likely to show more color change than the mechanically polished sample groups.Öğe Applied and computational investigation of plasticizing effects of dibutyl maleate on polymethyl methacrylate acrylic resin material(Elsevier, 2024) Tugut, Faik; Bolayir, Giray; Gulnahar, Evrem; Kaya, Savas; Boztug, Ali; Maslov, Mikhail M.In this study, the amount of change in the glass transition temperature (Tg) of PMMA was analyzed by DSC by adding different ratios of dibutyl maleate (DBM) plasticizer to polymethyl methacrylate (PMMA), which is used as the main ingredient of prosthetics in dentistry. For this, liquid DBM was added to powdered PMMA at a rate of 2, 5, 8 and 15 % by mass, and polymerization was carried out at 100 degrees C. Mechanical tests such as impact resistance, transverse resistance and maximum flexion tests were applied to these prepared mixtures. It was observed that there was a significant parallelism between the Tg values calculated from the DSC curves and the mechanical tests. The Tg value of PMMA was reduced by approximately half with the addition of DBM plasticizer. Additionally, the chemical interaction between PMMA and DBM was analyzed in the light of the Density Functional Theory (DFT) calculations. The binding energy for the mentioned interaction was determined as 1.591 eV. After both species interacted with each other, the glass transition temperature of the formed complex system was theoretically also predicted through the quantitative structure-property relationship (QSPR) model. For theoretical prediction of Tg, the molecular traceless quadrupole moment Theta and the molecular average hexadecapole moment phi, are used. The change determined as experimental in glass transition temperature as a result of the interaction between PMMA and DBM was supported with theoretical calculations. Experimental and theoretical data are in good agreement.Öğe Bond strength of a silicone soft lining material to poly(methyl methacrylate) resin treated with maleic anhydride and its terpolymers(TAYLOR & FRANCIS LTD, 2007) Turgut, Mehmet; Bolayir, Giray; Dogan, Orhan Murat; Keskin, Selda; Dogan, Arife; Boztug, AliThis study investigated the effectiveness of surface treatment of Poly (methyl methacrylate) (PMMA) denture base resin on tensile bond strength between PMMA/silicone-based soft liner. A total of 25 specimens were fabricated and assigned into five groups (n = 5). The surfaces of PMMA were treated with maleic anhydride, maleic anhydride-styrene-vinyl-acetate, n-butylmaleate-styrene-vinyl-acetate, or n-pentamaleate-styrene-vinyl-acetate prior to Primo adhesive primer application and silicone liner placement. The Primo adhesive primer on applied group untreated dentuse base resin served as control. The tensile test was performed using a universal testing machine. Fractured surfaces were observed under Scanning Electron Microscopy (SEM) and spectroscopic interpretation of the interfaces was done by Fourier Transform Infrared (FTIR). Test results showed that surface treatment increased interfacial strength giving the highest value for n-butylmaleatestyrenevinyl acetate treated group. SEM micrographs revealed that the specimens with n-butylmaleate-styrene-vinyl-acetate and n-pentamaleate-styrene-vinylacetate terpolymers underwent cohesive failure. FTIR analysis indicated secondary interactions such as hydrogen bonding, possibly on acrylic resin surfaces, caused by the use of maleic anhydride and its terpolymers, and the adhesive.Öğe Effect of bleaching on color change and refractive index of dental composite resins(JAPANESE SOC DENTAL MATERIALS DEVICES, 2008) Hubbezoglu, Ihsan; Akaoglu, Baris; Dogan, Arife; Keskin, Selda; Bolayir, Giray; Ozcelik, Suleyman; Dogan, Orhan MuratThis study investigated the effects of three bleaching agents (Whiteness Perfect, Whiteness Super, and Whiteness HP) on the color change and refractive index of three dental composites (Admira, Durafill VS, and Gradia Direct). Twenty diskshaped specimens (10 x 2 mm) of each composite were prepared and divided into four subgroups (n = 5). An unbleached group was used as a control, while the remaining specimens in the three subgroups were bleached with one of the bleaching agents respectively. Color change was assessed according to CIELAB color system and refractive indices were determined by phase modulated spectroscopic ellipsometry. Color differences between bleaching and baseline value (Delta E) were less than 3.3 for all groups. However, bleaching with Whiteness HP led to noticeable color changes for Admira and Durafill VS. While this agent had no effect on the refractive indices of these composites, the other two agents containing carbamide peroxide increased their refractive indices. Therefore, results suggested that replacement of such composite restorations may be required after bleaching.Öğe Effect of Bleaching on Roughness of Dental Composite Resins(TAYLOR & FRANCIS LTD, 2008) Dogan, Arife; Ozcelik, Suleyman; Dogan, Orhan Murat; Hubbezoglu, Ihsan; Cakmak, Mehmet; Bolayir, GirayThis study investigated the effect of three bleaching agents (Whiteness Perfect, Whiteness Super, Whiteness HP) on roughness of three dental resin composites (Admira, Durafill VS, Gradia Direct). Twenty disk-shaped standard specimens (102mm) of each composite material were prepared and divided into four subgroups (n=5). In each resin composite group, the unbleached specimens served as control; the other specimens were bleached with one of the bleaching agents according to the manufacturer's instruction. Roughness values were assessed using the atomic force microscope and metallographic microscope. Two-dimensional and 3D images were also taken for detecting surface alterations of each specimen group. Although the surfaces of all specimens did not seem to be smooth, the unbleached control specimens showed more irregular areas compared with those of the bleached ones. Roughness values were decreased in bleached groups to some extent depending on the bleaching agents used.Öğe The effect of Esthetic fibers on impact resistance of a conventional heat-cured denture base resin(JAPANESE SOC DENTAL MATERIALS DEVICES, 2007) Dogan, Orhan Murat; Bolayir, Giray; Keskin, Selda; Dogan, Arife; Bek, Bulent; Boztug, AliThis study was conducted to observe the changes in impact resistance of a denture base resin reinforced with five types of fiber. E-glass, polyester, rayon, nylon 6, and nylon 6/6 fibers were cut into 2, 4, and 6 mm lengths and added into the resin at a concentration of 3% by weight. Five test specimens for each formulation, as well as control specimens without fiber, were prepared using a mold including a V-shaped notch with 55 x 10 x 10 mm dimensions. Impact tests were carried out using a Charpy-type tester. Additionally, surfaces of the impact sections were observed under a scanning electron microscope (SEM). Results indicated that impact energy tended to increase with fiber length, and that the highest value was recorded for rayon fiber-reinforced specimens of 6 mm length. E-glass fiber reinforcement produced relatively stable, high values for each length, whereby good interfacial strength between polymer matrix and glass fibers was confirmed by SEM analysis.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 Light Curing Modes and Resin Composites on Temperature Rise under Human Dentin: An in vitro Study(JAPANESE SOC DENTAL MATERIALS DEVICES, 2008) Hubbezoglu, Ihsan; Dogan, Arife; Dogan, Orhan Murat; Bolayir, Giray; Bek, BulentThe influence of three curing modes of a high-powered LED curing unit on temperature rise under 2-mm-thick dentin was investigated during the polymerization of resin composite samples of Admira, Filtek P60. Premise, Tetric Flow, Tetric Ceram, and Filtek Z250. Ninety standard specimens were prepared. The bonding agents and resin composites were cured with standard, pulse, or soft-start mode (n=5 for each curing mode). Temperature rise was measured using a type 1, thermocouple. Data were analyzed by two-way ANOVA and Tukey's test. Soft-start curing led to statistically higher temperature rises compared than the other two modes. The highest temperature rise was observed for Admira and Tetric Flow cured with soft-start mode. The lowest temperature rise was observed for Premise cured with pulse mode. However, temperature rise did not reach the critical value that can cause pulpal damage by virtue of a prominent safety feature of the high-powered LED LCU, which ensures that no excessive heat is produced by all the three curing modes.Öğe The effects of maleic anhydride terpolymer and its ester derivatives on tensile bond strength between the acrylic resin and resilient lining material(JOHN WILEY & SONS INC, 2007) Dogan, O. Murat; Bolayir, Giray; Boztug, Ali; Turgut, Mehmet; Zengin, H. BayramThe present study investigated the effects on the bonding between the denture base acrylic resin and the soft silicon based lining material of maleic anhydridestyrene-vinyl acetate (MA-St-VA) terpolymer and some of its ester derivatives. These ester derivatives were n-propylmaleate-styrene-vinyl acetate (n-PrMA-St-VA), n-buthylmaleate-styrene-vinyl acetate (n-BuMA-St-VA) and n-benzylmaleate-styrene-vinyl acetate (n-BzMA-St-VA). Fourier Transform infrared spectroscopy method was used to determine interactions between terpolymers with the acrylic resin and soft lining material. The tensile bond strength of all the groups was compared and the obtained differences were statistically significant (P < 0.05). The highest value was found for the samples lined with n-BuMA-St-VA (2.11 +/- 0.21 MPa) and the samples lined with n-BzMA-St-VA had the lowest bond strength (0.3 +/- 0.1.2 MPa). (c) 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104:1338-1341, 2007.Öğe The effects of some methacrylate monomers used as liquid component on tensile and flexural strengths of a poly (methyl methacrylate) denture base resin(MATRICE TECHNOLOGY LIMITED, 2006) Do'an, Orhan Murat; Bolayir, Giray; Keskin, Selda; Boztug, Ali; Do'an, Arife; Bek, BuelentThis study was conducted to observe the effect of different monomers on tensile and flexural strengths of poly (methyl methacrylate) (PMMA) denture base resin when they were used as a liquid component. A conventional heat-cured denture base polymer powder was mixed with ethyl, isobutyl and tert-butyl methacrylate monomers, respectively. After the polymerization process was completed, the tensile and flexural strength values of these specimens were compared with those that of PMMA resin specimens polymerized with methyl methacrylate monomer (MMA). Tensile specimens were prepared in a dumbbell shape using a stainless steel mold constructed according to ASTM D638M-91a. Rectangular flexural specimens were prepared as designated in ASTM D790M-92. Each group was subjected to tensile strength and flexural strength tests using a crosshead speed of 50 mm min(-1) using a universal testing machine. In addition to mechanical tests, the structural change in the acrylic resin specimens prepared with different monomers was observed by Fourier Transform Infrared Spectrometer with Attenuated Total Reflectance unit (FTIR-ATR). The differences in the tensile strength values of all specimens were not found to be statistically significant (p > 0.05), whereas, the flexural strength values showed statistical differences among the groups tested (p < 0.05). In the results of the tests performed, it was reached that the flexural and tensile strength values of acrylic resins obtained by various methacrylate monomers were different. It can be said that these acrylic resins can be used for various aims in the different fields as well as in dentistry field.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 Evaluation of laser treatment on reline-base composites(TAYLOR & FRANCIS LTD, 2007) Bolayir, Giray; Turgut, Mehmet; Hubbezoglu, Ihsan; Dogan, Orhan Murat; Keskin, Selda; Dogan, Arife; Bek, BuelentThe effects of different laser treatments on some mechanical properties of acrylic resin and soft liner were investigated. A total of 60 test specimens were fabricated according to test requirements. The specimens were roughened with Potassium-ticanyl-Phosphate (KTP), Er:YAG, and Nd:YAG lasers before application of soft liner. The flexural, peel, and tensile bond strengths were measured using a universal testing machine. Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) spectra of surfaces were also obtained to evaluate changes on the lased surfaces. No significant difference was apparent between the tensile bond strength values of the groups. Although peel strength values obtained for each of the laser types were lower than those of the control group, flexural strength values were higher than those of the control specimens. The spectra of specimens showed that lasing led to some chemical changes on the resin surfaces. Physical changes on the treated surfaces were visualized by scanning electron microscopy (SEM) analysis. Results of this study suggest that such treatments may be warranted because of the increase in flexural strength.Öğe The evaluation of some flexural properties of a denture base resin reinforced with various aesthetic fibers(SPRINGER, 2008) Dogan, Orhan Murat; Bolayir, Giray; Keskin, Selda; Dogan, Arife; Bek, BuelentThis study was performed to determine whether some flexural properties of a denture base resin material could be improved through reinforcement with five types of aesthetic fibers at 3% concentration by weight and in 2, 4, and 6 mm length. Five specimens of similar dimensions were prepared for each of the test groups; base resin and the same resin with glass, rayon, polyester, nylon 6 and nylon 6,6 fibers in three different lengths. Flexural properties were evaluated by using a 3-point bending test. A visual examination was also made to determine mode of fracture of the specimens. The incorporation of different fibers in varying lengths had no significant effect on flexural strength of the resin. The specimens reinforced with nylon 6,6 fibers of 6 mm length showed the highest flexural strength. Young's modulus and maximum load suggests that such reinforcement makes resin resistant to fracture.Öğe Evaluation of the fracture resistance and failure types of different CAD-CAM ceramic crowns supported by angled titanium abutments(Wiley, 2023) Yuksel, Merve; Saygin, Aysegul Goze; Bolayir, GirayPurpose To evaluate the fatigue resistance of computer-aided design and computer-aided manufacturing (CAD-CAM) single-ceramic crowns which were applied on angled implant abutments after thermomechanical aging. Materials and Methods Titanium abutments (N = 72, MODE Medical Dental Implant, Turkey) with three different angles (0, 15 degrees, and 25 degrees) were restored using different materials (monolithic zirconia [Zir], lithium silicate ceramic reinforced by zirconia [VS], and hybrid ceramic [VE]). Crowns in the maxillary first premolar form were cemented to abutments using resin cement (Panavia 2.0 Introkit). Dynamic loading and thermomechanical aging were applied to the specimens (120,000 cycles, 49 N, 5-55 degrees C). Fracture resistance values were measured in the universal test machine and fracture types were determined. Two-way ANOVA and Tukey test were used for statistical analysis (Jamovi version 2.3.5). Results Both the abutment angle and the type of material had a significant effect on fracture resistance (F = 3.295, p < 0.05). The highest fracture resistance was obtained in Group 0-Zir, and the lowest fracture resistance was obtained in Group 15-VE. Fracture resistance showed significant differences between Group 0 and Group 15 for the Zir and VE materials, and between Group 0 and Group 25 for VS (p < 0.05); no statistical significance was determined between the other groups (p>0.05). When failure types were evaluated, they were seen to be full or partial crown fractures, and abutment deformation was found in some samples. Conclusions Monolithic crowns may be preferred on angled abutments. The fracture resistance of CAD-CAM materials decreases as the angle of abutments increases. Monolithic zirconia has higher fracture resistance than other materials.Öğe Flexural and bonding properties of a denture base polymer treated with nitric acid or ultraviolet radiation before relining with Molloplast-b(TAYLOR & FRANCIS LTD, 2007) Dogan, Orhan Murat; Keskin, Selda; Bolayir, Giray; Usanmaz, Ali; Bek, BuelentThis study investigated adhesive forces and flexural strength of acrylic resin denture base relined with Molloplast-B soft lining material. To increase bonding between the two materials, the surface of the resin was modified with ultraviolet (UV) irradiation or nitric acid treatment. The peel strength greatly increased with nitric acid treatment because of the high polarity on the poly (methyl methacrylate) (PMMA) surface and the increase in the surface roughness, whereas low peel strength was seen with the UV treatment of the PMMA surface. Although both types of the surface pretreatment increased the flexural strength of PMMA-reline composites compared with the control and bulk PMMA groups, the increase in the UV-treated group was found to be higher than that of the nitric acid treated group.Öğe Investigation of colour and surface changes of ceramic CAD/CAM blocks with different surface treatments after immersion to different beverages(Springer, 2022) Avsar, Melek Kilic; Bolayir, Giray; Saygin, Aysegul; Ulucan, Mehmet CagatayThis study aims to investigate the colour and surface changes of CAD-CAM porcelain blocks with different surface finishing treatments after being deposited into beverages. A total of 128 disc-shaped samples obtained from different CAD/CAM materials [Monolithic Zirconia (Z), Vita Suprinity (VS) and Vita Enamic (VE)] and feldspathic porcelain (FP) as the control group were divided into two subgroups [manual polish (M), glaze (G)] according to their surface finishing treatments. Measurements of the samples kept in different liquids (coffee and wine) after initial surface roughness and colour measurements (Delta E) were repeated on the 14th day. It was measured using a spectrophotometer for colour value measurement and an optical profilometer for surface roughness values, and SEM images were taken. When the initial and 14th-day surface roughness measurements were compared, significant differences were found in all groups (p < 0.05). The lowest roughness value (0.10 +/- 0.001) was obtained in the VS-M group aged into wine, while the highest roughness value (0.33 +/- 0.001) was obtained in the VE-M group aged into wine. Comparing the averages of colour changes (Delta E), the highest Delta E average was found in the FP-M group deposited into coffee (3.70 +/- 0.50), while the lowest Delta E value was found in the VE-M group deposited into wine (0.50 +/- 0.13). Depending on the structural characteristics of porcelain groups in terms of surface roughness and colour, we can say that the surface finishing treatment and beverage types have different effects.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.
