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Öğe Effects of high temperature on dental restorative materials for forensic purposes(Springer, 2021) Çarıkçıoglu, Burak; Misilli, Tuğba; Deniz, Yeşim; Aktaş, ÇağatayThis study aimed to observe the efects of high temperature on diferent restorative dental materials by detecting changes in their microstructural and elemental composition. Disk shaped samples (10 mm diameter, 2 mm depth) were prepared from 8 dental materials (compomer, glass carbomer, ormocer, giomer, zinc reinforced glass ionomer (GI), silver-alloy reinforced GI, zirconia reinforced GI, and conventional GI). Scanning electron microscopy/Energy dispersive X-ray spectroscopy (SEM/EDS) was used to characterize sample surface structures and elemental composition. The same samples were also analyzed using X-ray fuorescence (XRF) to determine the trace element content. Each sample was placed in a porcelain furnace and exposed to 900 °C for 30 min. Observations of macroscopic changes in samples after exposure high temperature were recorded. The microstructural changes in sample surfaces after incineration were detected by SEM. The elemental compositions obtained before and after the incineration were compared after repeating the XRF and EDS analyses. Dental materials demonstrated specifc macroscopic changes and microstructural deteriorations detected by SEM images after exposure to high temperature. While several changes occurred in the elemental content of materials in terms of amount, the original elemental composition was preserved. The ability to distinguish dental materials by elemental analyses has had an important impact on the identifcation process.Öğe Effects of radiotherapeutic X-ray irradiation on cervical enamel(Taylor and Francis Ltd., 2021) Deniz, Yeşim; Aktaş, Çağatay; Misilli, Tuğba; Çarıkçıoğlu, BurakPurpose Therapeutic radiation used for head and neck cancers mainly affects the cervical region of the tooth. To better understand the impact of therapeutic radiation on tooth, we aimed to examine the crystallinity, micro-morphology, and elemental composition of the cervical inner enamel located adjacent to the dento-enamel junction. Materials and methods Ninety-one specimens obtained from 16 impacted third mandibular molars were randomly divided into seven groups (0, 10, 20, 30, 40, 50, and 60 Gy irradiation groups). Energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM) were performed after the irradiation by 6 MV photon energy. The X-ray diffraction (XRD) were conducted in every group before and after irradiation. Elemental compositions, and Ca/P, P/N, Ca/N atomic ratios were subjected to the Shapiro-Wilk normality test. All of the elements except Mg showed a normal distribution and were compared by the one-way ANOVA. The non-normally distributed Mg data and Ca/P, P/N, and Ca/N ratios were compared by the Kruskal-Wallis test. Results The results showed that widening in the interprismatic spaces were observed in the experimental groups subjected to 30 Gy and the following increased doses. In addition, there were no significant differences in C, O, Ca, P, N percentages between irradiated and non-irradiated groups (p > .05). An increase in atomic ratio of the Mg was detected after samples conducted by 60 Gy radiation dose (p < .05). The stoichiometric Ca/P, Ca/N, and P/N atomic ratios did not change by irradiation (p > .05). The XRD peaks of the inner enamel crystalline phase showed a slight decline in the 60 Gy radiation dose group. Conclusion Radiation effects begin to be seen after 30 Gy radiation dose groups. The widen interprismatic spaces seen obviously in 50 Gy and 60 Gy dose groups. Besides Mg ratio showed an increase in the 60 Gy dose group. But it should be thought that radiation caries is a multi-factorial disease that is in collaboration with various radiation-induced side effects.Öğe Evaluation of the Effectiveness of Polyether Silicone-based and Polyvinyl Siloxane Dental Impression Materials for Shielding Scattered Radiation During Radiotherapy(Aydın Adnan Menderes University, 2023) Deniz, Yeşim; Aktaş, Çağatay; Işıktaş Acar, EzgiObjective: Radiation-induced oral mucositis is a major problem associated with radiotherapy. This study aimed to investigate the effectiveness of polyether silicone-based (PE) and polyvinyl siloxane (PVS) impression materials in protecting adjacent tissues from radiation scattered from dental materials. Materials and Methods: Amalgam, zirconium, and titanium dental material specimens were covered with 5 mm PE and PVS in the study group. The dental materials were placed in a linear accelerator device at a distance of 100 cm from the radiation source and coincided with a field size of 15x15 mm. Samples placed perpendicular to the central beam were irradiated with 6 MV photons at a fractional daily therapeutic radiation dose of 2 Gy. Thermoluminescent dosimeters (TLD-100) placed 90 degrees lateral to the specimens were used to record the scattered dose data. In the control group, uncovered dental materials were irradiated, and scattered doses were measured by TLD. The TLD data of the study and control groups were compared by independent t-test to analyze the shielding effect of PE and PVS. In addition, the photon stopper properties of PE and PVS were compared. The photon interaction parameters and effective atomic numbers of dental materials were calculated. Results: It was calculated that the PE and PVS significantly prevent the dose enhancement caused by dental materials (p<0.05). There was no difference between impression materials in the photon-stopping properties (p>0.05). Conclusion: PE and PVS can be used as scatter dose shields for the 2 Gy daily fractional dose. This study demonstrates the radiation-shielding properties of PE for the first time.Öğe Influence of Different Plaque Control Methods and Hydrothermal Aging on Structural Properties of Monolithic Zirconia(Adnan Menderes University, 2021) Öztürk Ulusoy, Habibe; Aktaş, ÇağatayObjective: This study aimed to investigate the effect of hydrothermal aging and various plaque removal methods, which are a part of professional dental cleaning, on zirconia’s structural properties. Materials and Methods: Seventy-two disk-shaped monolithic zirconia specimens (diameter 12 mm and thickness 1 mm) divided into six groups were subjected to no surface treatment, instrumentation with steel curette and ultrasonic steel scaler, and air abrasion with sodium bicarbonate, erythritol, and glycine before being aged in an autoclave at 0.2 MPa and 134 °C for 2 h. Specimens were analyzed using X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectrometry, and atomic force microscopy to evaluate crystal structure, microstructure, and surface roughness. Further, the contact angle and Vickers hardness measurements were performed for wettability and hardness evaluations. A biaxial bending test was applied to measure the durability of the material. Results: According to the results, no significant change was found in the crystal structure, surface roughness, and bending strength of zirconia (p>0.05). In contrast, a substantial decrease in surface hardness values and a significant increase in wettability values were observed in the steel curette and ultrasonic steel scaler groups compared with other groups (p<0.05). Conclusion: The use of abrasive powders in dental plaque control after prosthetic treatment can help maintain periodontal health and long-term use of prosthesis after restoration of monolithic zirconia.Öğe Investigation of Dosage Distributions of Polyvinyl Siloxane Dental Impression Shields for Head and Neck Radiotherapy with Thermoluminances Dosimeters(Marmara University, 2023) Ulusoy Öztürk, Habibe; Deniz, Yeşim; Aktaş, Çağatay; Gül Aygün, Esma BaşakObjective: This study aimed to assess the effects of denture materials on dose distribution on a head and neck radiotherapy-appropriate model and calculate the thickness of a stent by polyvinyl siloxane dental impression material for shielding scattered radiation from dental restorations. Methods: In the first step of the study, 5mm diameter and 5mm height of cylindrical dental material of titanium, zirconia lithium disilicate were irradiated with 6-Megavoltage photons from a clinical linear accelerator. In the second step, dental materials at the center of polyvinyl siloxane thicknesses of 5, 10, and 20mm were irradiated with 2 Gray and 10 Gray fractional doses. Measurements were made using three thermoluminescent dosimeters positioned laterally. The percentage backscattered dose and percentage dose decrease values were calculated to interpret the results. Results: According to the result, dosages scattered from dental materials increased for samples irradiated with 2Gy; a decreased dose was reported for samples irradiated with a 10Gy. 5mm PVS samples provided higher dose attenuation than others. Regardless of dental material, it is seen that the attenuation intensities calculated from TLD-100 dosimeters ranged from 22.7 to 38,62 for 2Gy, and 10.01 to 38,87 for 10Gy. Conclusion: Dental material alters the scattered radiation. In irradiated head and neck cancer patients, a 5mm thick guard is sufficient to prevent radiation diffused from dental materials in clinical usage.
