BackgroundImplants that can be used in the prosthetic rehabilitation of full and partial edentulous patients are now frequently used due to advances in dentistry. Despite advanced methods of applications, failures and complications can still be seen. The aim of our study was to evaluate clinical prosthetic values and complications that occurred during 4-year follow-up in implant-supported restorations.Material/MethodsThis retrospective study included 40 patients who received oral rehabilitation with an implant-supported prosthesis. A total of 162 implants were placed: 99 in the maxilla and 63 in the mandible. The prosthetic and surgical data were recorded. Data including prosthetic complications and implant loss were recorded and statistically analyzed using Cox proportional hazard regression analysis.ResultsIn total, 159 implants (98.14%) survived, 3 implants (1.86%) failed, and 100% of the protheses were successful. There were 62 dental implants used as abutments for removable dentures and 97 for fixed dentures. The most frequent prosthetic complications after placement of an implant-supported prosthesis were loss of retention, mucositis, abutment screw loosening, and fracture. Patient satisfaction after prosthesis use was also evaluated, showing that satisfaction was systematically increased.ConclusionsTo minimize the frequency of complications, protocols must be established from diagnosis to the completion of treatment and follow-up of implant-supported prostheses, especially in terms of adequate technical steps and careful radiographic evaluation of the components.

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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.

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Aim: To evaluate the stress distribution in the cortical bone under parafunctional forces with different occlusal thicknesses, monolithic zirconia with different implant diameters, and number variations in implant-supported fixed prosthetic restorations applied in patients with bruxism. Methodology: The tomographic sections of the previously registered mandible were used in order to model the mandible. Modeled bone height is 30 mm, cortical bone thickness is 1.5 mm, and trabecular bone thickness is modeled as 13 mm. By placing two implants in the created bone model, a three-member main model (Group 1), the number of implants was increased, three implants supported the Group 2 models, the diameter of the implants was increased, and the Group 3 models were created. The created Group 1, 2, 3 models, the occlusal thickness was divided into subgroups with 1.0, 1.5, and 2.0 mm, respectively (Groups A, B, and C). The groups were applied in two directions: vertical and 30o oblique. Stress values under forces were analyzed by finite element stress analysis. Results: Under vertical loading, the maximum principal stress value in the cortical bone was found to be lowest in Group 2C, and the highest maximum principal stress value was found in Group 1A. The minimum principal stress value in the cortical bone was found to be the lowest in Group 3C, and the highest minimum principal stress value was found in Group 1A. Under oblique loading, the maximum principal stress value in the cortical bone was found to be the lowest in Group 3C and the highest maximum principal stress value was found in Group 1A. The minimum principal stress value in the cortical bone was found to be lowest in Group 3C, and the highest minimum principal stress value was found in Group1A. Conclusion: Stresses caused by oblique forces are more than vertical forces. Increasing the occlusal thickness of the implant fixed prosthesis material, implant diameter, and number reduce the minimum and maximum principal stress values in the cortical   How to cite this article: Kantaci Y, Ülkü SZ. Evaluation of the stress distribution in the cortical bone caused by variations in implant applications in patients with bruxism: A three-dimensional finite element analysis. Int Dent Res 2021;11(Suppl.1):194-200. https://doi.org/10.5577/intdentres.2021.vol11.suppl1.27   Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

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.

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