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Evaluation of locking and non-locking reconstruction plate–screw system with lateral mandibular defects by FEA
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21st ICOMS 2013 - Abstracts: Oral Papers
T27.OR002
T27.OR004
Our experience in management of atrophic mandibular fractures: 2.0 mm locking plate system versus 2.4 mm locking plate system
A new ‘k’ shaped miniplate design for mandible angle fractures—mechanical test study
V. Basile ∗ , R. Saez Vigo, G. Novelli, F. Mazzoleni, A. Bozzetti
S. Kaman 1,∗ , I.D. Kocyigit 1 , H.H. Tuz 1 , B.T. Suer 2 , U. Tekin 1 1 Kirikkale
University Dentistry, Faculty Department of OMS, Turkey Gata Haydarpasa Training Hospital, Department of OMS, Turkey
Università Milano Bicocca, Ospedale San Gerardo, Monza, Italy
2
Background and objectives: Incidence of atrophic edentulous mandibular fractures is less than 1% of facial fractures. The fixation system may be the only way to enhance the outcome of treatment. The purpose of this study was to compare the outcomes of different plating system used for stabilization. Methods: Our sample included 23 patients treated for fractures of completely edentulous atrophic mandibles between 2004 and 2013. All patients had a panoramic X-rays and computed tomographic scans that allowed us to evaluate the class of atrophy according to the Luhr’s classification. 12 patients underwent open reduction and internal rigid fixation using 2.0 mm large profile locking bone plates, 11 patients were treated by 2.4 mm locking plates. Postoperative follow up was managed by clinical and radiographic revaluations. Results: Both patient groups achieved a complete fracture healing represented by clinical and radiographic union of fractured fragments. Conclusions: 2.0 mm large locking plate is thinner, less likely to expose through soft tissue, easier to adapt to the mandibular anatomy than 2.4 mm locking plate. However, according to the principle of load bearing fixation, 2.4 mm locking plate system still represents the reference hardware in severe mandibular atrophy. Key words: mandible; atrophy; fractures; plate system; edentulous
The aim of this study was to evaluate the efficiency of new titanium miniplate design (Modified Champy) resistance against the mechanical forces in mandible angle fracture. Thirty fresh sheep hemimandibles were assigned into three major (n = 10) and two subgroups (n = 5) and sectioned in the mandibular angle region to simulate the fracture. The bone segments fixed by 6 holes 2.0 mm non-compresion titanium miniplate via champy method and 6 holes 2.0 mm ‘k’ shaped titanium miniplate with 2.0 mm × 6 mm monocortical screws. After fixation hemimandibles were loaded in comprensive strength until a 4 mm displacement or fixation loose occured between the segments, vertically, horizontally and sagitally. ‘k’ shaped miniplate system (Modified Champy Technique) provided significantly greater resistance to displacement than conventional miniplate system (Champy Technique) (p < .01).
http://dx.doi.org/10.1016/j.ijom.2013.07.601 T27.OR003 Mandibular reconstruction with a newly designed Ti6Al4V modular endoprosthesis in macaca fascicularis N. Chanchareonsook 1,∗ , S. Lee 1 , H. Tideman 1 , S. Hollister 2 , C. Flanagan 2 , J.A. Jansen 3 1 Department
of Oral and Maxillofacial Surgery, National Dental Centre Singapore, Singapore Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI, USA 3 Department of Biomaterials, Radboud University Nijmegen Medical Centre, The Netherlands 2
Background: Mandibular modular endoprosthesis fixed with polymethylmethacrylate cement in the medullary space of the mandible to reconstruct segmental defects has been introduced in previous studies. However, device loosening and wound dehiscence have been reported. Objective: In vivo study of a newly designed non-cemented Ti6Al4V modular endoprosthesis. Methods: Endoprosthesis stems designed as hydroxyapatite coated tapered screws allow fitting into mandibular bone stumps without cementation. The body has a dove-tailed interlock with hydroxyapatite/bioglass surface coating. The devices were implanted for 6 months at unilateral mandibular segmental defects in 9 monkeys. Analysis was performed using biomechanical testing, histological and Micro CT analysis. Results: Mandibular contour and initial stability were satisfactory immediately post operation. 6 months after reconstruction, mechanical load bearing test showed mean stiffness value of 110.43 N/mm. Histomorphology analysis found 64.17% bone to stem contact. There was fibrous capsule and woven bone around the device body. Percent bone volume calculated from Micro-CT around the stem surface was found to be superior to previously reported cemented mandibular endoprosthesis. However, intraoral wound dehiscence was found in 6 animals. Conclusions: This newly designed mandibular endoprosthesis has potential in mandibular segmental reconstruction. Further modification to reduce wound dehiscence is required. Key words: mandible; endoprosthesis; bioglass; hydroxyapatite http://dx.doi.org/10.1016/j.ijom.2013.07.602
http://dx.doi.org/10.1016/j.ijom.2013.07.603 T27.OR005 Evaluation of locking and non-locking reconstruction plate–screw system with lateral mandibular defects by FEA G. Muftuoglu ∗ , B. Bayram Baskent University, Faculty of Dentistry, Department of Oral and Maxillofacial surgery, Turkey Objectives: The purpose of this study is to analyse and compare stess distrubiton on bone screws and plate systems in locking and non-locking screw–plates design with two different size of lateral mandibular defects. Methods: Solid mathematical model of the mandible was created by three dimensional finite elements analysis and two different lenght lateral resection was performed on model. Models were reconstructed with two different reconstruction plate system including three 2.4 mm titanium screws. Then resected bone lenght (2.5–5 cm) varied. Realistic mastication force was applied by simulating natural muscles vectors. The effects of plate–screw types to the stress formation on bone and hard-ware system were evaluated and compared. Results: The stress values of the cortical bone, plate and screw system of the conventional plate model was higher than the locking system model. The highest stress values were measured in the proximal segment especially in conjuction with convansional screw system. Furthermore, in use with locking system, the distribution of the stress on bone surface more homogeniously in both defect size. On the other hand in locking system, plates can subjected to much excessive force related with increasing defect size. Besides this, in large defect size a fatigue fracture of the plate itself can be occured by using locking system. On the bone surface, the amount of stress was less than conventional system and stress spreads wider area. Conclusion: It is evident that in the reconstruction model, the use of locking system offer an additional advantage over the conventional system particularly in small (25 mm) defects. Key words: locking plate; segmental resection; reconstruction; FEA; mechanical stress http://dx.doi.org/10.1016/j.ijom.2013.07.604
21st ICOMS 2013 - Abstracts: Oral Papers
T27.OR002
T27.OR004
Our experience in management of atrophic mandibular fractures: 2.0 mm locking plate system versus 2.4 mm locking plate system
A new ‘k’ shaped miniplate design for mandible angle fractures—mechanical test study
V. Basile ∗ , R. Saez Vigo, G. Novelli, F. Mazzoleni, A. Bozzetti
S. Kaman 1,∗ , I.D. Kocyigit 1 , H.H. Tuz 1 , B.T. Suer 2 , U. Tekin 1 1 Kirikkale
University Dentistry, Faculty Department of OMS, Turkey Gata Haydarpasa Training Hospital, Department of OMS, Turkey
Università Milano Bicocca, Ospedale San Gerardo, Monza, Italy
2
Background and objectives: Incidence of atrophic edentulous mandibular fractures is less than 1% of facial fractures. The fixation system may be the only way to enhance the outcome of treatment. The purpose of this study was to compare the outcomes of different plating system used for stabilization. Methods: Our sample included 23 patients treated for fractures of completely edentulous atrophic mandibles between 2004 and 2013. All patients had a panoramic X-rays and computed tomographic scans that allowed us to evaluate the class of atrophy according to the Luhr’s classification. 12 patients underwent open reduction and internal rigid fixation using 2.0 mm large profile locking bone plates, 11 patients were treated by 2.4 mm locking plates. Postoperative follow up was managed by clinical and radiographic revaluations. Results: Both patient groups achieved a complete fracture healing represented by clinical and radiographic union of fractured fragments. Conclusions: 2.0 mm large locking plate is thinner, less likely to expose through soft tissue, easier to adapt to the mandibular anatomy than 2.4 mm locking plate. However, according to the principle of load bearing fixation, 2.4 mm locking plate system still represents the reference hardware in severe mandibular atrophy. Key words: mandible; atrophy; fractures; plate system; edentulous
The aim of this study was to evaluate the efficiency of new titanium miniplate design (Modified Champy) resistance against the mechanical forces in mandible angle fracture. Thirty fresh sheep hemimandibles were assigned into three major (n = 10) and two subgroups (n = 5) and sectioned in the mandibular angle region to simulate the fracture. The bone segments fixed by 6 holes 2.0 mm non-compresion titanium miniplate via champy method and 6 holes 2.0 mm ‘k’ shaped titanium miniplate with 2.0 mm × 6 mm monocortical screws. After fixation hemimandibles were loaded in comprensive strength until a 4 mm displacement or fixation loose occured between the segments, vertically, horizontally and sagitally. ‘k’ shaped miniplate system (Modified Champy Technique) provided significantly greater resistance to displacement than conventional miniplate system (Champy Technique) (p < .01).
http://dx.doi.org/10.1016/j.ijom.2013.07.601 T27.OR003 Mandibular reconstruction with a newly designed Ti6Al4V modular endoprosthesis in macaca fascicularis N. Chanchareonsook 1,∗ , S. Lee 1 , H. Tideman 1 , S. Hollister 2 , C. Flanagan 2 , J.A. Jansen 3 1 Department
of Oral and Maxillofacial Surgery, National Dental Centre Singapore, Singapore Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI, USA 3 Department of Biomaterials, Radboud University Nijmegen Medical Centre, The Netherlands 2
Background: Mandibular modular endoprosthesis fixed with polymethylmethacrylate cement in the medullary space of the mandible to reconstruct segmental defects has been introduced in previous studies. However, device loosening and wound dehiscence have been reported. Objective: In vivo study of a newly designed non-cemented Ti6Al4V modular endoprosthesis. Methods: Endoprosthesis stems designed as hydroxyapatite coated tapered screws allow fitting into mandibular bone stumps without cementation. The body has a dove-tailed interlock with hydroxyapatite/bioglass surface coating. The devices were implanted for 6 months at unilateral mandibular segmental defects in 9 monkeys. Analysis was performed using biomechanical testing, histological and Micro CT analysis. Results: Mandibular contour and initial stability were satisfactory immediately post operation. 6 months after reconstruction, mechanical load bearing test showed mean stiffness value of 110.43 N/mm. Histomorphology analysis found 64.17% bone to stem contact. There was fibrous capsule and woven bone around the device body. Percent bone volume calculated from Micro-CT around the stem surface was found to be superior to previously reported cemented mandibular endoprosthesis. However, intraoral wound dehiscence was found in 6 animals. Conclusions: This newly designed mandibular endoprosthesis has potential in mandibular segmental reconstruction. Further modification to reduce wound dehiscence is required. Key words: mandible; endoprosthesis; bioglass; hydroxyapatite http://dx.doi.org/10.1016/j.ijom.2013.07.602
http://dx.doi.org/10.1016/j.ijom.2013.07.603 T27.OR005 Evaluation of locking and non-locking reconstruction plate–screw system with lateral mandibular defects by FEA G. Muftuoglu ∗ , B. Bayram Baskent University, Faculty of Dentistry, Department of Oral and Maxillofacial surgery, Turkey Objectives: The purpose of this study is to analyse and compare stess distrubiton on bone screws and plate systems in locking and non-locking screw–plates design with two different size of lateral mandibular defects. Methods: Solid mathematical model of the mandible was created by three dimensional finite elements analysis and two different lenght lateral resection was performed on model. Models were reconstructed with two different reconstruction plate system including three 2.4 mm titanium screws. Then resected bone lenght (2.5–5 cm) varied. Realistic mastication force was applied by simulating natural muscles vectors. The effects of plate–screw types to the stress formation on bone and hard-ware system were evaluated and compared. Results: The stress values of the cortical bone, plate and screw system of the conventional plate model was higher than the locking system model. The highest stress values were measured in the proximal segment especially in conjuction with convansional screw system. Furthermore, in use with locking system, the distribution of the stress on bone surface more homogeniously in both defect size. On the other hand in locking system, plates can subjected to much excessive force related with increasing defect size. Besides this, in large defect size a fatigue fracture of the plate itself can be occured by using locking system. On the bone surface, the amount of stress was less than conventional system and stress spreads wider area. Conclusion: It is evident that in the reconstruction model, the use of locking system offer an additional advantage over the conventional system particularly in small (25 mm) defects. Key words: locking plate; segmental resection; reconstruction; FEA; mechanical stress http://dx.doi.org/10.1016/j.ijom.2013.07.604