In this work, the dry turning of Inconel 601 alloy in a dry environment with PVD-coated cutting inserts was studied. Turning was performed at various cutting speeds, feeds, insert shapes, corner radii, rake angles, and approach angles. After machining, arithmetic mean surface roughness (Ra) and flank wear (VB) were measured, and the material removal rate was also calculated (MRR). An analysis of variance (ANOVA) was performed to determine the effects of the turning input parameters. For the measured values, the turning process was modeled using an artificial neural network (ANN). Based on the obtained model, the process parameters were optimized using a genetic algorithm (GA). The objective function was to simultaneously minimize Ra and VB and maximize MRR. The accuracy of the model and the optimal values were further validated by confirmation experiments. The maximum percentage errors, which are less than 2%, indicate the possibility of practical implementation of the hybrid approach for modeling and optimization of dry turning of Inconel 601 alloy.

Introduction. An autologous bone (bone derived from the patient himself) is considered to be a ?golden standard? in the treatment of bone defects and partial atrophic alveolar ridge. However, large defects and bone losses are difficult to restore in this manner, because extraction of large amounts of autologous tissue can cause donor-site problems. Alternatively, data from computed tomographic (CT) scan can be used to shape a precise 3D homologous bone block using a computer-aided design-computer-aided manufacturing (CAD-CAM) system. Case report. A 63-year old male patient referred to the Clinic of Dentistry of Vojvodina in Novi Sad, because of teeth loss in the right lateral region of the lower jaw. Clinical examination revealed a pronounced resorption of the residual ridge of the lower jaw in the aforementioned region, both horizontal and vertical. After clinical examination, the patient was referred for 3D cone beam (CB)CT scan that enables visualization of bony structures and accurate measurement of dimensions of the residual alveolar ridge. Considering the large extent of bone resorption, the required ridge augmentation was more than 3 mm in height and 2 mm in width along the length of some 2 cm, thus the use of granular material was excluded. After consulting prosthodontists and engineers from the Faculty of Technical Sciences in Novi Sad we decided to fabricate an individual (custom) bovine-derived bone graft designed according to the obtained 3D CBCT scan. Conclusion. Application of 3D CBCT images, computer-aided systems and software in manufacturing custom bone grafts represents the most recent method of guided bone regeneration. This method substantially reduces time of recovery and carries minimum risk of postoperative complications, yet the results fully satisfy the requirements of both the patient and the therapist.

The beneficial effect of autologous blood products in the post-extraction period has been proven regarding acceleration of soft tissue healing, pain reduction, swelling and trismus, but data concerning bone healing are contradictory. The objective of this study was to evaluate the effect of L-PRF on bone tissue healing after third mandibular molar extraction. Extractions of bilateral, symmetrical, impacted mandibular molars were performed in 30 patients, in a prospective split-mouth, randomized, double-blind clinical trial. L-PRF was applied to one alveolus, while the other alveolus was left to heal spontaneously. A sample of 60 extraction alveoli (the control and experimental groups, with 30 alveoli each) was analyzed. Two CBCT images were performed immediately after the surgery and eight weeks postoperatively to reconstruct the healing site and analyze the volume of the extraction defect and bone density. The depth of the periodontal pocket on the adjacent tooth was clinically measured 7 days and 8 weeks after extraction. The results show that the minimum and maximum values of the monitored parameters in the alveoli in both the control and experimental groups are within the expected range. Based on p = 0.826 (MANOVA; for I measurement) and p = 0.499 (MANOVA; for II measurement), it was concluded that no significant difference and clearly defined boundary between the groups were observed. Considering that p > 0.1 (VOL, bone density, periodontal pocket) is for both I and II measurement, no significant difference was observed between the groups regarding the wound volume, bone density and periodontal pocket.