The study of temporomandibular joint (TMJ) and its relationship to function of the stomathognathic system has been a topic of interest in dentistry for many years. This relationship has proved to be quite complex. The TMJ is certainly one of the most complex joints in the body. As knowledge of the anatomy and physiology of the TMJ increases, and instruments and techniques for measuring dynamic skull-fossamandibular factors are developed, many more general dentists are attempting to -and are expected to-diagnose and treat TMJ-oriented problems. Temporomandibular disorders (TMD) include clinical disorders involving the masticatory muscles, the TMJ and the adjacent structures. TMD was recognized as a main source for pains in the orofacial area, which are not caused from dental origin, and is defined by the American Academy of Orofascial Pain (AAOP) as a sub-group within the frame of musculoskeletal disorders. The main etiology for TMD has not been found yet.
PURPOSEIn this study, we aimed to evaluate the amount of marginal gap with two different substructure materials using identical margin preparations.MATERIALS AND METHODSTwenty 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.RESULTSAccording to the results obtained, the marginal gap in the galvano copings before cementation was measured as, on average, 24.47 ± 5.82 µm before and 35.11 ± 6.52 µm after cementation; in the laser-sintered Co-Cr structure, it was, on average, 60.45 ± 8.87 µm before and 69.33 ± 9.03 µm 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.CONCLUSIONMarginal 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.
The aim of this study was to compare the histologic findings from the condyles of rats with the general system findings. 30 SpragueDawley adult rats were used. The rats were sacrified and their condyles and femurs were examined histologically. The rats' weight were observed weekly, their femoral height and weight, femoral mineral elements, and their daily food and water consumes were recorded. The results were analysed statistically by using SPSS (10.0). During the histologic examination of femur, the osteogenesis and calcification of the femur layers of the male/female rats in the experimental group were found to be lower than those of the ones in the control group. In addition to that, during the histological examination of condyle the level of thickness of condyle layers, the number of cellular elements, the osteogenesis and calcification seemed to be decreased for the male/female rats in the experimental group than for those in the control group. The decrease was found to be more significant for the female rats than the male rats in experimental group and it is thought that this is related to the gonad hormones. These findings emphasize that a reduction of sex hormone levels, induced by adrenalectomy, significantly influences condylar histogenesis.
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