Diş Hekimliği Fakültesi / Faculty of Dentistry
Permanent URI for this collectionhttps://hdl.handle.net/11727/2120
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Item Stress Distribution on Short Implants at Maxillary Posterior Alveolar Bone Model With Different Bone-to-Implant Contact Ratio: Finite Element Analysis(2016) Yazicioglu, Duygu; Bayram, Burak; Oguz, Yener; Cinar, Duygu; Uckan, Sina; 26867093The aim of this study was to evaluate the stress distribution of the short dental implants and bone-to-implant contact ratios in the posterior maxilla using 3-dimensional (3D) finite element models. Two different 3D maxillary posterior bone segments were modeled. Group 1 was composed of a bone segment consisting of cortical bone and type IV cancellous bone with 100% bone-to-implant contact. Group 2 was composed of a bone segment consisting of cortical bone and type IV cancellous bone including spherical bone design and homogenous tubular hollow spaced structures with 30% spherical porosities and 70% bone-to-implant contact ratio. Four-millimeter diameter and 5-mm-height dental implants were assumed to be osseointegrated and placed at the center of the segments. Lateral occlusal bite force (300 N) was applied at a 25 degrees inclination to the implants long axis. The maximum von Mises stresses in cortical and cancellous bones and implant-abutment complex were calculated. The von Mises stress values on the implants and the cancellous bone around the implants of the 70% bone-to-implant contact group were almost 3 times higher compared with the values of the 100% bone to -implant contact group. For clinical reality, use of the 70% model for finite element analysis simulation of the posterior maxilla region better represents real alveolar bone and the increased stress and strain distributions evaluated on the cortical and cancellous bone around the dental implants.Item Effects of Platelet-Rich Fibrin Membrane on Sciatic Nerve Regeneration(2018) Bayram, Burak; Akdeniz, Sidika Sinem; Diker, Nurettin; Helvacioglu, Fatma; Erdem, Saban Remzi; 0000-0002-7825-1083; 0000-0002-6026-0045; 0000-0002-7537-2170; 29381631; AAS-4519-2020; AAH-8887-2021; AAJ-2370-2021Alternative treatment approaches to improve the regeneration capacity of damaged peripheral nerves are currently under investigation. The objective of the present study was to evaluate the effects of platelet-rich fibrin (PRF) membrane after sciatic nerve crush injury in rabbits by histomorphometric and electromyographic analysis. The left sciatic nerves of 20 male Vienna rabbits were clamped for 30seconds to induce crush injuries. Animals were randomly divided into 2 groups: PRF and control. For each animal in the PRF group, a PRF membrane was wrapped around the injured part of the sciatic nerve to form a tube. No additional treatment was performed in the control group. After a 12-week healing period, tissue samples from the injured nerve region were harvested and the g-ratio of axons, axon density, and impulse transmission changes were evaluated. Analysis revealed that axon density differences were not statistically significant between groups (P=0.139). The rate of nerve fibers with optimum g-ratio was significantly lower in the PRF group than in the control group (P=0.02). Conduction velocity differences between groups were not statistically significant. Although PRF application has previously shown positive regeneration effects on maxillofacial tissues, local PRF membrane application in tube form did not show any histomorphometric or functional improvement in peripheral nerve crush injury recovery.Item Treatment efficiency of activator and skeletal anchored Forsus Fatigue Resistant Device appliances(2020) Ince-Bingol, Sinem; Kaya, Burcak; Bayram, Burak; Arman-Ozcirpici, Ayca; 0000-0002-7014-0784; 32671559Objectives The aim of the study was to investigate the treatment efficiency of miniplate anchored Forsus Fatigue Resistant Device (MAF) as compared with the activator appliance. Materials and methods Mandibular retrognathia was treated with two methods, the MAF group (8 girls, 11 boys, mean age 13.03 +/- 0.69 years) and the activator group (7 girls, 12 boys, mean age 12.68 +/- 0.73 years). An untreated control group (9 girls, 10 boys, mean age 12.95 +/- 0.73 years) was constructed to eliminate growth-related changes through the American Association of Orthodontists Foundation Legacy Collection. Data of 114 lateral cephalograms were analyzed. Results The inhibition of the maxillary growth was greater in the MAF group, whereas forward displacement of the mandible was higher in the activator group (P < 0.05). Sagittal maxillomandibular relation was improved similarly in both treatment groups (P < 0.05). Mandibular length was increased in both treatment groups with the highest increase in the activator group (P < 0.05). Retroclination of the incisors was observed in the MAF group (P < 0.05). The upper lip was retruded in the MAF group and lower lip was protruded in the activator group (P < 0.05). Conclusion The activator created greater mandibular changes, whereas the MAF provides somewhat smaller mandibular changes due to the restriction caused by retroclined maxillary incisorsItem Effect of Induced Membrane on Guided Bone Regeneration in an Experimental Calvarial Model(2020) Altiparmak, Nur; Akdeniz, Sidika Sinem; Akcay, Eda Yilmaz; Bayram, Burak; Araz, Kenan; 0000-0001-6831-9585; 31934967; AAK-1960-2021Objective: The aim of this study was to evaluate the effect of induced membrane on guided bone regeneration and to compare its effect with poly-tetra-flourur-ethylene (PTFE) membrane and collagen membrane. Methods: Sixteen white Vienna rabbits were used for experiments. Initially 1 defect was created on the parietal bone of all animals and cement was placed inside the defects. After 8 weeks, the bone cements were removed, without damaging the induced membrane formed in the defect cavity. And then 2 more defects were created. All defects were filled with xsenogenic graft materials and were covered with newly formed induced membrane, d-PTFE membrane and collagen membrane. Eight animals were sacrificed at 4th week and other 8 animals were sacrificed at 8th week and all bone specimens were histologically evaluated. Results: New bone formation and bone marrow ratios were significantly higher in induced membrane and d-PTFE membrane group compared to collagen membrane group (P < 0.05) at 4th week. Mature bone ratios were significantly higher in induced membrane and d-PTFE membrane group compared to collagen membrane group (P < 0.05) at 8th week. The best CD31 value was detected with d-PTFE membrane group at 4th week and with induced membrane at 8th week. Conclusion: Induced membrane can act as a strong barrier membrane and stimulate bone regeneration. Induced membrane technique can be accepted as a good alternative for the reconstruction of critical size defects in maxillofacial region.Item Comparison of Success Rate of Dental Implants Placed in Autogenous Bone Graft Regenerated Areas and Pristine Bone(2020) Altiparmak, Nur; Akdeniz, Sidika Sinem; Diker, Nurettin; Bayram, Burak; Uckan, Sina; 32282668Autogenous bone grafting still has been considered as the "gold standard" and wildly used in the case of alveolar bone reconstruction. The aim of the present study is to evaluate the success rate of implants placed in autogenous block augmented ridges and implants placed in pristine bone (PB). This study included 113 patients. Fifty-three patients were treated with autogenous block grafts and particulate bone, after 6 months of healing implant placements were performed in autogenous bone augmented (ABA) areas. In 60 patients implant placement was performed, with no need for grafting and implants were placed into the PB. Follow-up data (pain, mobility, exudation from peri-implant space, success rate, marginal bone resorption) were collected after 5 years of prosthetic loading. The cumulative implant success rate at the 5-year examination was 92.45% for the ABA group and 85% for PB group. There were 3 failed implants in the ABA group and 3 in PB group. Average marginal bone loss was 1.47 mm on ABA group and 1.58 mm on PB group. No statistically significant differences for pain, exudation from peri-implant space, implant mobility, implant success, peri-implant bone loss parameters, and patient satisfaction level were found between groups. The obtained data demonstrated that the success rate of implants placed in regenerated areas are very similar to the success rate of implants those placed in PB.Item Positive effect of platelet rich fibrin on osseointegration(2016) Oncu, Elif; Bayram, Burak; Kantarci, Alpdogan; Gulsever, Serap; Alaaddinoglu, Emine-Elif; 0000-0001-6718-3882; 27475686Background: Leukocyte-platelet rich fibrin (L-PRF) is a second generation platelet concentrate clinically used to accelerate tissue healing and bone regeneration. Achieving reduced implant osseointegration time could provide immediate or early loading of implants. The aim of this study was to evaluate the L-PRF-induced osseointegration and bone-implant contact (BIC) in an experimental animal model. Material and Methods: Twelve 4-month-old New Zealand white rabbits were used. Following general anesthesia, 3-5 mL of blood was obtained from the central artery in rabbit ear and L-PRF was prepared. Two implant cavities (5 mm long and 3 mm in diameter) were created in each tibia with a total of four cavities in each animal. Two of these cavities were selected and covered with PRF (test group). The remaining L-PRF was used to soak the implants placed into the L-PRF covered sockets. Other cavities were left as controls. In total, 48 implants were placed. Animals were sacrificed after two, three, or four weeks. Histological samples were obtained and peri-implant tissues were histomorphometrically evaluated for bone-to-implant contact and new bone formation. Results: Histomorphometric analyses of the defects revealed that the L-PRF was detectable up to the second week. Application of L-PRF increased the rate and amount of new bone formation in the experimental group compared to the control group. Bone-to-implant contact was enhanced when the surface was pre-wetted with L-PRF (p<0.01). Conclusions: The results of this study demonstrated that L-PRF application may increases amount and rate of new bone formation during the early healing period and provides a faster osseointegration around implants.Item Comparison of Tunnel and Crestal Incision Techniques in Reconstruction of Localized Alveolar Defects(2017) Altiparmak, Nur; Uckan, Sina; Bayram, Burak; Soydan, Sidika; 28520823Purpose: The aim of this study was to compare the complication rates of recipient sites prepared using two incision techniques: crestal and tunnel. Materials and Methods: In this prospective study, patients underwent augmentation procedures (68 patients; 75 sites) by the same surgeon that were performed consecutively using the crestal incision technique (27 horizontal, 10 vertical; crestal group) or the tunnel incision technique (27 horizontal, 11 vertical; tunnel group). Autogenous bone block grafts were harvested with a piezoelectric surgical device, and the grafts were fixed at the recipient sites by two titanium screws in both groups. The authors evaluated minor exposure, transient paresthesia, major exposure, permanent paresthesia, gingival recession at adjacent teeth, surgery time, and visual analog scale pain scores. Results: Soft tissue dehiscence and graft failure were significantly lower in patients undergoing the tunnel technique. Conclusion: The tunnel incision technique significantly decreased soft tissue exposure, the most common complication of augmentation procedures with autogenous onlay bone grafts. This technique should be considered an alternative to the crestal incision technique for preparation of the recipient site.