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    CAN HISTOLOGICAL AND HISTOMORPHOMETRICAL CHANGES BE INDUCED IN RAT MANDIBULAR CONDYLE FOLLOWING OVARIECTOMY AND LONG-TERM EXTREMELY LOW FREQUENCY MAGNETIC FIELD EXPOSURE?
    (Taylor & Francis Ltd, 2012) Ulku, Sabiha Zelal; Akdag, Mehmet Zulkuf; Yavuz, Izzet; Celik, Mustafa Salih; Ketani, Muzaffer Aydin
    The quantity and quality of maxillary and mandibular bone have long been a focus of attention for dental clinicians. The mandibular condyle is a major growth site and plays an important role during mandibular growth. The aim of the present study was to evaluate the effects of long-term extremely low frequency magnetic field (ELF-MF) and hormonal changes produced by bilateral ovariectomy on the histologic and histomorphometric structure of rat mandibular condyle. Forty mature female Sprague-Dawley rats were randomly divided into four different groups (n = 10): control (Cnt), ovariectomy (OVX), ELF-MF exposure (ELF-MF), ELF-MF exposure with OVX application (ELF-MF+OVX). All rats were subjected to bilateral ovariectomy except those in Cnt and ELF-MF groups. ELF-MF and ELF-MF+OVX groups were exposed to 1.5 mT ELF-MF during 6 months, 4 h a day After all applications, left condyle of rats were removed to examine histopathologically. Some histopathologic changes were observed, such as irregular appearance in bone marrow cavities in rat condyles of OVX, ELF-MF and ELF-MF+OVX groups. Some disorders in transition from hypertrophic field to ossification layer and irregular appearance in calcification were determined in OVX group. In OVX+ELF-MF and ELF-MF groups, there was significant disruption and latency in calcification and ossification areas. However, no significant differences were found in the thickness of the condylar cartilage layer between groups (P > 0.05). It was suggested that long-term ELF-MF exposure and ELF-MF exposure with ovariectomy application can affect the histologic structure of rats' condyle. Consequently, it was concluded that long-term ELF-MF exposure and ovariectomy application can induce histopathological changes in the structure of the condyle and ELF-MF exposure cannot alter ovariectomy-induced changes.
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    Evaluation and comparison of the marginal adaptation of two different substructure materials
    (Korean Acad Prosthodontics, 2015) Karaman, Tahir; Ulku, Sabiha Zelal; Zengingul, Ali Ihsan; Guven, Sedat; Eratilla, Veysel; Sumer, Ebru
    PURPOSE. In this study, we aimed to evaluate the amount of marginal gap with two different substructure Materials using identical margin preparations. MATERIALS AND METHODS. Twenty stainless steel models with a chamfer were prepared with a CNC device. Marginal gap measurements of the galvano copings on these stainless steel models and Co-Cr copings obtained by a laser-sintering method were made with a stereomicroscope device before and after the cementation process and surface properties were evaluated by scanning electron microscopy (SEM). A dependent t-test was used to compare the mean of the two groups for normally distributed data, and two-way variance analysis was used for more than two data sets. Pearson's correlation analysis was also performed to assess relationships between variables. REAMS. According to the results obtained, the marginal gap in the galvano copings before cementation was measured as, on average, 24.47 +/- 5.82 mu m before and 35.11 +/- 6.52 mu m after cementation; in the laser-sintered Co-Cr structure, it was, on average, 60.45 +/- 8.87 mu m before and 69.33 +/- 9.03 mu m after cementation. A highly significant difference (P<.001) was found in marginal gap measurements of galvano copings and a significant difference (P<.05) was found in marginal gap measurements of the laser-sintered Co-Cr copings. According to the SEM examination, surface properties of laser sintered Co-Cr copings showed rougher structure than galvano copings. The galvano copings showed a very smooth surface. CONCLUSION. Marginal gaps values of both groups before and after cementation were within the clinically acceptable level. The smallest marginal gaps occurred with the use of galvano copings.
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    Öğe
    Influences of extremely low frequency magnetic fields on mineral and trace elements content of rat teeth
    (Academic Journals, 2008) Yavuz, Izzet; Akdag, M. Zulkuf; Dasdag, Suleyman; Ulku, Sabiha Zelal; Akkus, Zeki
    Exposure to extremely low frequency magnetic fields (ELF-MF) emanating from the generation, distribution, and utilization of electricity is widespread. The major debate in recent years has focused on the possibility that exposure to ELF-MF may result in adverse health consequences. The present study was carried out to investigate the effects of ELF-MF on the mineral content in rat teeth. 27 male Sprague-Dawley rats were divided into three groups: two experimental (each, n=10), one control sham (n=7). After ELF-MF and sham exposure, some mineral levels (Ca, Mg, Zn, and P) were determined with Atomic Absorbtion Spectrophotometry (AAS). It was determined that Ca levels increased in the two experimental groups as compared to the sham group (p<.05). The levels of Ca, Mg, Zn, and P in second experimental group rats were also higher than sham group (p<.05). The results demonstrate that ELF-MF can have significant effects on teeth mineral content. Future observations and epidemiological studies of ELF-MF effects should be accompanied by laboratory experiments to evaluate oral and dental effects.