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Öğe Allogenic versus Autogenous Bone Rings in Dental Implant Surgery: Guidance of Stress Analysis-Part II(Amer Scientific Publishers, 2018) Ozgul, Ozkan; Altay, Berkan; Atil, Fethi; Onder, M. Ercument; Tekin, Umut; Yilmaz, Seda; Kocyigit, Ismail DorukObjective The aim of this study is to compare the stress distribution along the alveolar bone following the allogenic and autogenous bone ring assisted immediate dental implant surgery using three dimensional finite element analyses Material and Methods Finite element models of maxilla and mandible that augmented with autogenous and allogenic bone ring graft with dental implant were created Vertical force of 100 N and oblique force of 100 N at 45(degrees) angle were applied to root formed design dental implant and abutment Results The highest calculated values of VonMisses (VM) stresses were observed in oblique loaded mandible model which augmented with allogenic graft In all models the highest VM stress values were greater for oblique loading compare to vertical loadings Allogenic bone ring grafts contribute the stresses more evenly through the implant, as for the autogenous grafts stresses are concentrated in the neck area of the implant Discussion Allogenic and autogenous grafts applied with implant placement create different stress distributions Stress distributions should be considered when choosing type of biomaterial.Öğe Choosing Implant Type for Using with Allogeneic Bone Ring Graft: Guidance of Stress Analysis-Part I(Amer Scientific Publishers, 2018) Ozgul, Ozkan; Kocyigit, Ismail DorukObjective: The aim of this study is to compare the stress distribution of three different implant macro design applied with allogeneic cancellous bone rings using three dimensional finite element analyses. Material and Methods: Finite element models of maxilla and mandible that augmented with allogeneic bone ring graft with implants were created. Vertical force of 100 N and oblique force of 100 N at 45 degrees angle were applied to three different (variable thread, cylindrical, standard thread) macro design implants. Results: Stress concentrations in the conjunction of neck of the implant and allogeneic bone ring were higher than other areas. The highest calculated values of Von Misses stresses were observed in standard thread implant with oblique loading in mandible model. In all models the highest stress values were greater for oblique loading compare to vertical loading. Discussion: Implant macro designs shows different distributions to implanted bone or graft. It should be considered when choosing an implant in the cases augmented with allogeneic cancellous bone ring.Öğe Effect of Locally Administered Alendronate on Onlay Grafts(Amer Scientific Publishers, 2017) Tekin, Umut; Ozgul, Ozkan; Tuz, Hakan; Korkusuz, Petek; Kocyigit, Ismail Doruk; Atil, Fethi; Onder, M. ErcumentObjective: The present study compared the effects of local alendronate application on the osteogenesis of autogenous and xenogenous onlay grafts implanted in rabbit mandibles. Material and Methods: 28 New Zealand rabbits were used in this experimental animal study. The animals were randomly divided into 4 groups according to graft material as follows: D1: autogenous graft-saline; D2: 60% autogenous graft-40% alendronate D3: xenogenous bone graft-saline; D4: 60% xenogenous graft-40% alendronate. 3 histologic parameters were evaluated: the ratio of new bone formation to the total defect area, the active osteoblast-lined bone length, and the ratio of osteocyte-filled lacunae to total lacunae. At the same time, the grafted zones were evaluated using dual-energy X-ray absorptiometry (DEXA) and the Bone mineral density scores were measured. Results: The present study showed better results for the group receiving alendronate applied to autogenous graft when compared to other groups. Discussion: The administration of alendronate increases the resistance of autogenous graft; it may also enhance new bone formation and increase the viability of xenograft. Further animal studies supported with biomechanical tests are required prior to human studies.Öğe Effect of Locally Applied bFGF on Implant Stability: Biomechanical Evaluation of 2 Different Implant Surfaces in Rabbits(Lippincott Williams & Wilkins, 2014) Kartal, Yasemin; Ucok, Cahit; Ozgul, Ozkan; Kocyigit, Ismail Doruk; Suer, Berkay TolgaObjectives: The aim of this study was to evaluate the implant stability with the addition of local application of basic fibroblast growth factor (bFGF) during the osseointegration of 2 different dental implant surfaces using rabbit tibia model. Materials and Methods: Fifty-six dental implants, 28 of hydrophilic surface (SLActive) and 28 of hydrophobic surface (OsseoSpeed), were placed in 14 mature New Zealand rabbits. The rabbits each received both SLActive and OsseoSpeed implants per tibia, and bFGF was applied locally on 1 randomly selected tibia. Half of the subjects were killed at the fourth week of healing period, and the other half were killed at the twelfth week. Stabilization was assessed using resonance frequency analysis (RFA) and removal torque value (RTV). Results: The local application of bFGF was found to enhance osseointegration, especially at the fourth week of healing period after application (P = 0.046). RFAs and RTVs were found to be higher in bFGF-treated implant with hydrophilic surfaces when compared with both bFGF-treated hydrophobic implants and nontreated hydrophilic controls. Conclusion: Local application of bFGF seems to increase the stabilization values in implants with hydrophilic surfaces and those with hydrophobic surfaces.Öğe Effect of Systemic Oxytocin Administration on New Bone Formation and Distraction Rate in Rabbit Mandible(W B SAUNDERS CO-ELSEVIER INC, 2020) Altay, Berkan; Dede, Eda Ciftci; Ozgul, Ozkan; Atil, Fethi; Kocyigit, Ismail Doruk; Orhan, Kaan; Tekin, UmutPurpose: The main disadvantage of distraction osteogenesis is the prolonged treatment protocol. Recently, oxytocin (OT) has been found to have anabolic effects on bone metabolism. In this experimental study, the effects of OT on the mandibular distraction gap in rabbits at 2 different distraction rates were evaluated. Materials and Methods: This experimental study was conducted on 28 male New Zealand white rabbits. The animals were divided into 3 experimental groups and 1 control group. Group A (control group, n = 7) consisted of animals with distraction at a rate of 1 mm/day, and group B (n = 7) consisted of animals with a distraction rate of 2 mm/day; groups A and B received postoperative saline solution injection. Group C (n = 7) consisted of animals with distraction at a rate of 1 mm/day, and group D (n = 7) consisted of animals with a distraction rate of 2 mm/day; postoperative OT injection was performed in groups C and D. Results: Both histomorphologic and micro-computed tomography evaluations showed increased bone healing in the OT-treated groups. Conclusions: On the basis of the evaluation of both the histomorphometric and micro-computed tomographic data, systemic OT administration was found to increase new bone formation and bone healing with distraction osteogenesis. (C) 2020 American Association of Oral and Maxillofacial SurgeonsÖğe Evaluation of Advanced Platelet Rich Fibrin (A-PRF) on Bone Healing. Is It Better than Old Version? A Histological Animal Study(Amer Scientific Publishers, 2017) Titirinli, Kubra; Tekin, Umut; Atil, Fethi; Onder, M. Ercument; Senguven, Burcu; Ozgul, Ozkan; Kocyigit, Ismail DorukObjective: This study aims to evaluate the effect of fibrin, which is formed with an alteration to the standard PRF centrifugation protocol, on the bone formation. The study additionally aims to assess cell-distribution, and to evaluate the effects of alterations in the speed and duration of centrifugation on the changes in cell-distribution and the formation of hard tissue, by making histological investigations. Materials and methods: Ten New Zealand rabbits were used in this experimental animal study. PRF (2700 rpm, 12 min) and APRF (1500 rpm, 14 min) were placed in the standard bone defects that formed in the right corpus of the mandible randomly. No additional material was placed in the left mandible defect, as a control group. Rabbits were sacrificed after two months, the histological evaluation was performed. Results: There were no marked differences between groups in regard to the quantity of bone formation and bone quality. The quantities of new bone formation were (mean) 56.9%, 55%, 42.5%. Discussion: It may be considered that PRF and its variations have positive effects on the new bone tissue and cell number, and may lead to more rapid ossification compared to the unprocessed bone defects.Öğe Evaluation of Preoperative Model Surgery and the Use of a Maxillary Sinus Surgical Template in Sinus Floor Augmentation Surgery(Lippincott Williams & Wilkins, 2013) Kocyigit, Ismail Doruk; Coskunses, Fatih Mehmet; Ozgul, Ozkan; Tuz, Hakan Hifzi; Kartal, Yasemin; Polat, Muhlis; Orhan, KaanMaxillary sinus augmentation is an accepted technique for dental implant placement in presence of insufficient maxillary bone. There are various techniques in the literature, either by crestal or lateral approach in maxillary sinus augmentation that have high percentage of success, while all have complications. Schneiderian membrane perforation is the most common complication encountered during surgery. The aim of this study was to evaluate the benefits of preoperative model surgery and the ease of use of a maxillary sinus surgical template (MSST) during maxillary sinus augmentation surgery with a lateral approach. Ten patients included in the study needed rehabilitation of a partially or totally edentulous maxilla with an implant-supported fixed prosthesis and requiring sinus augmentation. A questionnaire was asked to performing surgeons, and study results showed the use of an MSST was found to be effective in terms of adaptation (62.5%), window preparation (87.5%), ease of elevation (95.9%), ease of grafting (95.9%), reduction of perforation risk (91.7%), and achieving immobility during the procedure (62.5%); however, the use of an MSST was also found to prolong the surgical procedure (100%) and restrict the view of the surgical area (79.2%). Maxillary sinus augmentation appears to be a useful tool for locating an appropriate entrance to the sinus cavity, allowing for safe elevation of the sinus membrane and effectively grafting the sinus floor.Öğe A Simple Solution for Vector Control in Vertical Alveolar Distraction Osteogenesis(Allen Press Inc, 2014) Kocyigit, Ismail Doruk; Tuz, Hakan H.; Ozgul, Ozkan; Coskunses, Fatih Mehmet; Kisnisci, Reha S.One of the important and frequent complications in alveolar distraction osteogenesis is vectorial change of the transport segment. This report presents a simple solution for vector angulation control by placing intermaxillary fixation screws intraoperatively. Advantages of the technique are also discussed.Öğe Stress Analysis of Zygomatic Implants on the Augmented Maxillary Sinus: Is It Necessary to Graft?(Lippincott Williams & Wilkins, 2017) Kaman, Suleyman; Atil, Fethi; Tekin, Umut; Ozgul, Ozkan; Onder, Mustafa Ercument; Yilmaz, Seda; Kocyigit, Ismail DorukPurpose: Zygomatic implants are becoming an ideal therapy with advanced implant-supported prosthetic treatment for the posterior atrophic maxilla. The purpose of this study is to examine the quantity and distribution of stress, which was caused by zygomatic implants placed using intrasinus method with or without augmentation to the atrophic posterior maxilla. Materials & Methods: In this study, 3-dimensional atrophic edentulous maxilla models with and without sinus augmentation are designed with computer-aided programs. Stress analysis was carried out on the created computer models for maxillary alveolar cortical bone, for cortical bone in the zygomaticomaxillary suture, and for zygomatic spongy bone at the apex of the zygomatic implant and for metal substructure of Von Misses stress data. Results: Having augmented the maxillary sinus with graft, it was observed that after the loading especially in the posterior region, the tensile and compressive stresses on the alveolar crest was distributed more homogeneously and the stress generated on the cortical bone was reduced through the graft. Conclusion: Although zygomatic implants are graftless solutions for athrophic maxilla, sinus augmentation will be useful for bearing stress around the implants.
