- Email: [email protected]
Biomechanical and animal-experimental results of a new osteosynthesis material made from shape memory alloy
Int. J. Oral Maxillofac. Surg. 2005; 34 (Supplement 1): $ 1 - $ 1 8 1
84 were subcutaneously administered into the cervical back for 3 weeks (Group SC). Experiment 3) 5 pg of rhBMP-2 and 1 ml of atellocollagen solution was mixed with SVA (1.5 mg or 3.0 mg/disk). A BMP-SVA pellet was made and implanted the same as above, as the simultaneous implantation group (Group SI). On day 21 after implantation, each pellet was removed and ectopically formed bone was evaluated. PO and the SC groups that used SVA showed no significantly stimulative effects. Other groups showed increased new bone volume and wet weight, projected and radiopaque areas as observed on X-ray film, and calcium contents that were significantly higher than those in the control group. In the SC group that used SV, ALP and TRAP activities were lower than those in the control group. In the SI group, ALP and TRAP activities were higher than those in the control group. In the PO group, SV or SVA appeared to show no effect on ectopic bone formation because large amounts of them accumulated in the liver. In the SC group, it was speculated that SV was more effective on osteogenic cells because it is more lipophilic than SVA. In the SI group, the degree of ALP activity was superior to that of TRAP activity with high bone turnover. These results suggest that various pathways of simvastatin administration have different effects on ectopic osteoinduction. There is the possibility that simultaneously implanted simvastatin could become a useful adjuvant for enhancing BMP-2 induced bone formation.
046. Trauma V
[•
THE USE OF BIODEGRADABLE PLATES AND SCREWS TO STABILIZE FACIAL FRACTURES
R. Bell, C. Kindsfater. Department of Oral and Maxillofacial Surgery Legacy Emanuel Hospital and Health Center and Oregon Health & Science University Portland, Oregon, USA The purpose of this preliminary retrospective study is to review the demographics and outcome of patients with a variety of facial fractures that were stabilized with PL bone plates and screws. The records of 295 consecutive patients with facial fractures treated by open reduction and internal fixation, performed by the author from 2001 through 2003, were retrospectively reviewed. The data collected included variables such as demographic information, fracture pattern, method/material of fixation and outcome. Excluded from the study were those patients with inadequate records or at least 3 weeks follow-up. All fractures were approached in the standard fashion and stabilized utilizing either 1.5 mm or 2.0 mm titanium or biodegradable fixation plates and screws placed with adherence to standard AO-ASIF principles. Patients were selected to receive biodegradable fixation on the basis of mechanism of injury, the degree of bony displacement demonstrated on clinical and radiographic examination, patient age, and fracture pattern or location. Intermaxillary fixation for a period of 1 to 2 weeks and guiding elastics were used when appropriate. Outcome measures such as infection, non-union, mal-union, and were identified and subjectively assessed. Descriptive statistics were recorded and an analysis of variants performed in an effort to identify predictors of poor outcome. 281 patients met the criteria for inclusion in the study (age: 2-92 years, mean =29.1; M=160, F=45) with follow-up of 3 weeks to 3 years. 44/205 (21%) patients with a variety of facial fractures were identified as having received biodegradable plates and screws. All patients eventually went on to satisfactory healing with favorable restoration of form and function. Complications occurred in 14 patients overall ( 7 % ) a n d included: infection (n=7), malunion (n=4), non-union (n = 1), enopthalmos (n = 1), ectropion (n = 1 ) a n d entropion (n= 1). Neither age, sex, fixation material, nor fracture pattern was a significant predictor of complications (p>.05). Favorable healing can be observed through the use of biodegradable PL plates and screws to stabilize selected midface fractures in patients of all ages, as well as mandible fractures in early childhood. [~6~]
USE OF RESORBABLE PLATES FOR TRAUMATOLOGY OF THE FACIAL SKELETON - 3 YEARS REVIEW
S. Kyriakou, E. Parara, N. Papadogeorgakis, P. Christopoulos, C. Perisanides, N. Mavrovouniotis, S. Dimtsas, S. Sotiriadou, K. Alexandridis. University of Athens, Oral and Maxillofacial Dept.,
Athens, Greece To present our experience with resorbable plates for fixation of facial fractures We reviewed the data of 20 patients with facial fractures who
underwent open reduction and fixation with resorbable plates in the dept of Oral and Maxillofacial surgery of Evangelismos General Hospital, over the last 3 years. Twenty patients aged 18-40 years were treated. Seven were female. In all patients resorbable plates were used mainly because of the young age of the patients. 48 mini resorbable plates were used both in the mandible and maxilla. Intraoperative difficulties associated with the lurning curve were the most common complication. No infection or secondary motility was noted in any patient. Resorbable plates have been successfully used in oral and maxillofacial surgery and orhtopedics over the last years. Biocompatibility and excellent pliance are great advantages, especially in pediatric trauma.
~--]A
NEW RESORBABLE FIXATION TECHNIQUE IN CRANIOFACIAL SURGERY
U. Eckelt 1 , E. Pilling 1 , E. Stelnicki 2. 1Dept.of Oral and Maxillofacial
Surgery, Technical University, Dresden, Germany; 2Memorial Medical Office Centre, Hollywood, USA A new method for osteosynthesis in oral and craniomaxillofacial surgery is presented. Resorbable PDLLA pins in different diameters and lengths can be driven by utrasonic power providing a direct fusion of the pin into cortical as well as cancellous bone with extraordinary stability. The pins design is unique and has especially been designed for this purpose. The mechanical stability and the biocompatibility of the technology was investigated in vivo in two different animal models as a comparison between the normal resorbable screw fixation and the new pin system. The study was performed over a period of 6 months. In the lower jaw of 20 adult female sheep one 1.6 x 5 mm and a 2.1 x 5 mm resorbable screw and two pins with the same diameter have been inserted for the semiquantitative evaluation of the histological response. To investigate the biomechanical stability a lamb model of craniosynostosis was created. Skull defects were produced on both sides of 15 lambs in the age of 3 months. On one side they have been treated with a mesh and screw combination and on the other with the new pin fixation system. After the sacrifice of the animals tensible and bending test have been done and the histology of non-decalcified sections was performed for cell morphology and bone remodeling activity. A statistically significant advantage for the new pin fixation system could be established in the field of the mechanical stability as well as for the needed operation time. We found no inflammation at the soft tissue covering the screws and pins and normal new bone formation and remodelling activity around the both different implants. Bone degradation or resorption as result of the mechanical stress by the ultrasonic power couldn't be recorded. Using this procedure for fixing a PDLLA plate or mesh, the pins ally immediately to a plate or mesh by merging the materials together. This is confirmed by the excellent biomechanical results of the new pin fixation system. As only pre-drilling with special drill bits is required, time-consuming tapping is completely skipped which is considered a huge benefit especially in treating pediatric craniofacial syndroms.
•G-4-•
BIOMECHANICAL AND ANIMAL-EXPERIMENTAL RESULTS OF A NEW OSTEOSYNTHESIS MATERIAL MADE FROM SHAPE MEMORY ALLOY
R. Sader, H. Schieferstein, A. Abeln, T. Wetzel, T. Keller, B. Exner, E J0rgens, H.-E Zeilhofer. Department of craniomaxillo- and plastic
facial surgery, University Hospital of Frankfurt, Theodor-Stern-Kai 7, D-60590 Frankfurt/Main, Germany Primary fracture healing after osteosynthetic treatment of jaw fractures could be obtained so far only with a compression osteosynthesis. Autocompressive shape memory materials were not suitable because of its high transformation temperature and lacking biocompatibility regarding bone healing. Aim of the study to evaluate a new osteosynthesis material by biomechanical and biocompatibilty tests. In biomechanical preliminary tests at six jaw models the biomechanical stability was investigated by conventional mini plates versus a new clip system made from shape memory material. Subsequently, one took place in-vivo experiments at 7 Beagle dogs attained full growth. After randomization the mandibula was osteotomized and then fixed with the clip system versus to a conventional osteosynthesis. In a sub-group the new osteosynthesis material was coated by plasma immersion ion implantation to improve biocompatibility. After 3 weeks the animals were sacrificed and the fracture healing was examined fluorescence-microscopically and histologically. In biomechanical testing it was proven that an osteosynthesis with 3 clips guaranteed
Oral Presentations/O47. Other IV the same torsion and bending stability high-significantly as with 2 mini plates. Due to their superelasticity by the shape memory efffect the clips however showed superiory over the conventional material concerning gaping. The histological evaluation showed that using the clips a primary fracture healing could be obtained. Coated clips exhibited thereby a better a osseointegration. The accomplished investigations show that this new osteosynthesis material can be used in the treatment of fractures of the facial skeleton. The biomechanical properties of that new osteosynthesis material show superiority over conventional methods.
[-O-~-]
MINIPLATE OSTEOSYNTHESIS WITH FOUR DIFFERENT SYSTEMS IN SHEEP
85 cases. In children there were more advantages because of the facial growth that is not affected with the fixation. In adults we opted in used resorbale material in fractures with no or minimal muscle influence in the estability. The complications observed were no related with resorbable material. More patients, more and extensive follow-ups is needed. References
[1] Ricalde P, Posnick JC. Degradation rate of delta (resorbable) internal fixation: report of two cases. J Oral Maxillofac Surg. 2004 62(2):250-5. [2] Norholt SE, Pedersen TK, Jensen J. LeFort I miniplate osteosynthesis: a randomized, prospective study comparing resorbable PLLA/PGA with titanium. Int J Oral Maxillofac Surg 2004 245-52.
R. Gutwald, R. SchSn, N.-C. Gellrich, M. Metzger, J. Kuschnierz, N. Weyer, R. Schmelzeisen. Department of ©ral and Maxillofacial
047. Other IV
Surgery, University of Freiburg, Germany The purpose of this investigation was to evaluate the influence on bone healing following osteosynthesis in the mandible of sheep with four different 2.0 miniplate systems. ST = Miniplates with Self-Tapping Screws. The screws were inserted manually after predrilling. SDF = Miniplates with Self-Drilling-Forming Screws. The screws, which formed their own thread into the bone, were inserted manually without predrilling. SDT-L = Self-Drilling-Tapping-Locking. The screws had a drill-like tip and a separate selftapping shaft. A special thread beneath the screw head was designed to lock into corresponding threaded plate holes. They were inserted with a special micro-motor-machine. ST-L = SelfTapping-Locking. The screws had also a thread beneath the screw head in order to lock into the plate holes. The screws were inserted manually after predrilling. In 24 sheep a standardised osteotomy was performed at the right premolar space. Osteosynthesis was performed with one of the above mentioned systems. Sacrification time points were at 4 and 8 weeks. After computer-tomography and assistance of a Navigationsystem the callus formation was measured. Histological analysis was performed at each osteotomy. After 4 and 8 weeks the highest callus formation was seen by the SDF-System followed by the ST- and SDT-LSystem. The Locking-System ST-L showed the lowest callus formation. In relation to the osteotomy gap the lowest percentage of new bone formation after 4 weeks was observed with the ST-, SDF- and SDT-LSystems whereas the highest rate of bone formation was seen by the ST-L-System. After 8 weeks an increase of bone formation within the ST-, SDF- and SDT-L-Systems could be observed, coming up to comparable values as the ST-L-System. The Self-Tapping-Locking-System showed the highest stability. Therefore the clinical use of this system in difficult cases should be supported.
[-0--'~
THE USE OF POLYLACTIC IMPLANTS AND PLATES (DELTA SYSTEM - LEIBINGER) IN ORAL AND MAXILLOFACIAL TRAUMA: A PRELIMINARY REPORT
EB. Mariani, L.E.C. Pagotto, A.R.S. Colucci, L.C. Manganello-Souza.
Associa~o Brasileira de OdontologiaABO Sec~o S~o Paulo, Hospital Municipal de Urg#ncias, Guarulhos, Brazil The purpose of this study was to evaluate and report our initial experience with a resorbable fixation system in maxillofacial trauma. The specific goals were to evaluate the stability, complications, advantages and disadvantages of the use of resorbable. From January 2004 to January 2005 we operated 15 cases of facial fractures including 4 children and 11 adults from 4 to 53 years of age. Children were treated with a single 1.7 mm plate. The adults fractures evolved were 4 blow-out orbital floor fractures, 5 zigomatic fractures, 2 LeFort II fracture. Blowout fractures were treated with resorbable mesh for orbital floor reconstruction. Zigomatic fractures and LeFort II fractures were treated with fixation in two points with 2.2 mm resorbable plate. We observed 1 case of superficial infection in angle mandibular fracture in a 7 years old child with Congenital Acquired Immunodefiency Syndrome, which presented a bilateral mandibular fracture. It was used Clindamicine 600 mg/day for 10 days to treat with good result. The others cases presented a good healing of the mandibular fractures with no mobility after a mean of 8 months post-operatively. In adult cases we observed one case of post-operative diplopia in very high supra-version, and the patient opted for no new surgical intervention. In one case of LeFort II fracture we observed what we considered a high level of maxillary mobility and opted for 10 days of maxillo-mandibular immobilization with successful result. Resorbable plates and mashes bring a good result in maxillofacial trauma in selected
•G-•'-•
HISTOLOGICAL EVALUATION OF DERMIS GRAFTS FOLLOWING DISCECTOMY IN THE RABBIT CRANIOMANDIBULAR JOINT
G. Dimitroulis 1 , J. Slavin 2. Departments of 1Special Surgery and
2Anatomical Pathology, St. Vincent's Hospital Melbourne, The University of Melbourne, Australia The purpose of this study is to determine the histological fate of the full thickness skin graft when placed into the temporomandibular joint using a rabbit model. Fourteen New Zealand white rabbits were used and divided into 3 groups. Two rabbits were used as controls (Group A) whereby a sham operation was undertaken. In six rabbits (Group B) the joint capsule of the left craniomandibular joint (CMJ) was surgically breached and the wound was repaired. The remaining six rabbits (Group C) also had the same surgical procedure to the left CMJ but with the interpositional placement of a full thickness skin graft which was taken from the skin of their necks. All grafts were placed above the head of the condyle and firmly secured to the surrounding tissues with non-resorbable sutures. The rabbits were sacrificed at 1, 3 and 5 months following surgery and the left CMJ's were histologically prepared and examined under light microscopy. The interpositional skin graft in all experimental animals (Group C) were found adjacent to the condyle on the lateral aspect rather than above the condylar head where it was originally sutured in place. Significant atrophy and reduction in the number and size of the skin appendages such as sweat glands and hair follicles was found within the grafted skin of all experimental animals compared to normal skin. All the grafts demonstrated evidence of epidermoid inclusion cysts. The full thickness skin graft may not be a suitable interpositional material for the TMJ because of the high risk of epidermoid cyst formation and the propensity for lateral displacement of the graft even when sutured into the appropriate intra-articular position.
[O4•
THE ROLE OF INTERLEUKIN (IL)-II~, IL-6 AND IL-8 IN PATHOGENESIS OF ODONTOGENIC CYSTS
K. Isik 1 , H. Ataoglu 2 , S. Haliloglu 3. 1Oral and Maxillofacial Department,
Selcuk University, Faculty of Dentistry, Konya, Turkey; 2Oral and Maxillofacial Department, Selcuk University, Faculty of Dentistry, Konya, Turkey; 3Biochemistry Department, Selcuk University, Faculty of Veterinary, Konya, Turkey, Oral and Maxillofacial Department, Baskent University, Faculty of Dentistry, Konya, Turkey The purpose of this study was to determine IL-11-~, IL-6 and IL-8 levels in odontogenic cyst fluids and, if exists, to find that whether the size, location and type of the cyst has an effect on the type and amount of ILs. Cystic fluids aspirated from 15 radicular, 7 dentigerous and 4 keratocysts were subjected to enzyme immuno assay test to determine IL-11-~, IL-6 and IL-8 levels. According to our results, there was no relationship between the IL levels and location or size of the lesions (p>0.05). On the other hand, when the IL types were compared, it was found that smaller cysts had less IL-11-~than IL-8 and larger cysts had less IL-11-~than IL-6 and IL-8 (p<0.01). When keratocysts were evaluated, there was no significant correlation between IL types (p>0.05). In dentigerous cysts, IL-11-~was significantly less than IL-6 and IL-8. In radicular cysts, IL-11-~was again less than IL-8 (p<0.01). IL-11-~, IL-6 and IL-8 should have an effect in
84 were subcutaneously administered into the cervical back for 3 weeks (Group SC). Experiment 3) 5 pg of rhBMP-2 and 1 ml of atellocollagen solution was mixed with SVA (1.5 mg or 3.0 mg/disk). A BMP-SVA pellet was made and implanted the same as above, as the simultaneous implantation group (Group SI). On day 21 after implantation, each pellet was removed and ectopically formed bone was evaluated. PO and the SC groups that used SVA showed no significantly stimulative effects. Other groups showed increased new bone volume and wet weight, projected and radiopaque areas as observed on X-ray film, and calcium contents that were significantly higher than those in the control group. In the SC group that used SV, ALP and TRAP activities were lower than those in the control group. In the SI group, ALP and TRAP activities were higher than those in the control group. In the PO group, SV or SVA appeared to show no effect on ectopic bone formation because large amounts of them accumulated in the liver. In the SC group, it was speculated that SV was more effective on osteogenic cells because it is more lipophilic than SVA. In the SI group, the degree of ALP activity was superior to that of TRAP activity with high bone turnover. These results suggest that various pathways of simvastatin administration have different effects on ectopic osteoinduction. There is the possibility that simultaneously implanted simvastatin could become a useful adjuvant for enhancing BMP-2 induced bone formation.
046. Trauma V
[•
THE USE OF BIODEGRADABLE PLATES AND SCREWS TO STABILIZE FACIAL FRACTURES
R. Bell, C. Kindsfater. Department of Oral and Maxillofacial Surgery Legacy Emanuel Hospital and Health Center and Oregon Health & Science University Portland, Oregon, USA The purpose of this preliminary retrospective study is to review the demographics and outcome of patients with a variety of facial fractures that were stabilized with PL bone plates and screws. The records of 295 consecutive patients with facial fractures treated by open reduction and internal fixation, performed by the author from 2001 through 2003, were retrospectively reviewed. The data collected included variables such as demographic information, fracture pattern, method/material of fixation and outcome. Excluded from the study were those patients with inadequate records or at least 3 weeks follow-up. All fractures were approached in the standard fashion and stabilized utilizing either 1.5 mm or 2.0 mm titanium or biodegradable fixation plates and screws placed with adherence to standard AO-ASIF principles. Patients were selected to receive biodegradable fixation on the basis of mechanism of injury, the degree of bony displacement demonstrated on clinical and radiographic examination, patient age, and fracture pattern or location. Intermaxillary fixation for a period of 1 to 2 weeks and guiding elastics were used when appropriate. Outcome measures such as infection, non-union, mal-union, and were identified and subjectively assessed. Descriptive statistics were recorded and an analysis of variants performed in an effort to identify predictors of poor outcome. 281 patients met the criteria for inclusion in the study (age: 2-92 years, mean =29.1; M=160, F=45) with follow-up of 3 weeks to 3 years. 44/205 (21%) patients with a variety of facial fractures were identified as having received biodegradable plates and screws. All patients eventually went on to satisfactory healing with favorable restoration of form and function. Complications occurred in 14 patients overall ( 7 % ) a n d included: infection (n=7), malunion (n=4), non-union (n = 1), enopthalmos (n = 1), ectropion (n = 1 ) a n d entropion (n= 1). Neither age, sex, fixation material, nor fracture pattern was a significant predictor of complications (p>.05). Favorable healing can be observed through the use of biodegradable PL plates and screws to stabilize selected midface fractures in patients of all ages, as well as mandible fractures in early childhood. [~6~]
USE OF RESORBABLE PLATES FOR TRAUMATOLOGY OF THE FACIAL SKELETON - 3 YEARS REVIEW
S. Kyriakou, E. Parara, N. Papadogeorgakis, P. Christopoulos, C. Perisanides, N. Mavrovouniotis, S. Dimtsas, S. Sotiriadou, K. Alexandridis. University of Athens, Oral and Maxillofacial Dept.,
Athens, Greece To present our experience with resorbable plates for fixation of facial fractures We reviewed the data of 20 patients with facial fractures who
underwent open reduction and fixation with resorbable plates in the dept of Oral and Maxillofacial surgery of Evangelismos General Hospital, over the last 3 years. Twenty patients aged 18-40 years were treated. Seven were female. In all patients resorbable plates were used mainly because of the young age of the patients. 48 mini resorbable plates were used both in the mandible and maxilla. Intraoperative difficulties associated with the lurning curve were the most common complication. No infection or secondary motility was noted in any patient. Resorbable plates have been successfully used in oral and maxillofacial surgery and orhtopedics over the last years. Biocompatibility and excellent pliance are great advantages, especially in pediatric trauma.
~--]A
NEW RESORBABLE FIXATION TECHNIQUE IN CRANIOFACIAL SURGERY
U. Eckelt 1 , E. Pilling 1 , E. Stelnicki 2. 1Dept.of Oral and Maxillofacial
Surgery, Technical University, Dresden, Germany; 2Memorial Medical Office Centre, Hollywood, USA A new method for osteosynthesis in oral and craniomaxillofacial surgery is presented. Resorbable PDLLA pins in different diameters and lengths can be driven by utrasonic power providing a direct fusion of the pin into cortical as well as cancellous bone with extraordinary stability. The pins design is unique and has especially been designed for this purpose. The mechanical stability and the biocompatibility of the technology was investigated in vivo in two different animal models as a comparison between the normal resorbable screw fixation and the new pin system. The study was performed over a period of 6 months. In the lower jaw of 20 adult female sheep one 1.6 x 5 mm and a 2.1 x 5 mm resorbable screw and two pins with the same diameter have been inserted for the semiquantitative evaluation of the histological response. To investigate the biomechanical stability a lamb model of craniosynostosis was created. Skull defects were produced on both sides of 15 lambs in the age of 3 months. On one side they have been treated with a mesh and screw combination and on the other with the new pin fixation system. After the sacrifice of the animals tensible and bending test have been done and the histology of non-decalcified sections was performed for cell morphology and bone remodeling activity. A statistically significant advantage for the new pin fixation system could be established in the field of the mechanical stability as well as for the needed operation time. We found no inflammation at the soft tissue covering the screws and pins and normal new bone formation and remodelling activity around the both different implants. Bone degradation or resorption as result of the mechanical stress by the ultrasonic power couldn't be recorded. Using this procedure for fixing a PDLLA plate or mesh, the pins ally immediately to a plate or mesh by merging the materials together. This is confirmed by the excellent biomechanical results of the new pin fixation system. As only pre-drilling with special drill bits is required, time-consuming tapping is completely skipped which is considered a huge benefit especially in treating pediatric craniofacial syndroms.
•G-4-•
BIOMECHANICAL AND ANIMAL-EXPERIMENTAL RESULTS OF A NEW OSTEOSYNTHESIS MATERIAL MADE FROM SHAPE MEMORY ALLOY
R. Sader, H. Schieferstein, A. Abeln, T. Wetzel, T. Keller, B. Exner, E J0rgens, H.-E Zeilhofer. Department of craniomaxillo- and plastic
facial surgery, University Hospital of Frankfurt, Theodor-Stern-Kai 7, D-60590 Frankfurt/Main, Germany Primary fracture healing after osteosynthetic treatment of jaw fractures could be obtained so far only with a compression osteosynthesis. Autocompressive shape memory materials were not suitable because of its high transformation temperature and lacking biocompatibility regarding bone healing. Aim of the study to evaluate a new osteosynthesis material by biomechanical and biocompatibilty tests. In biomechanical preliminary tests at six jaw models the biomechanical stability was investigated by conventional mini plates versus a new clip system made from shape memory material. Subsequently, one took place in-vivo experiments at 7 Beagle dogs attained full growth. After randomization the mandibula was osteotomized and then fixed with the clip system versus to a conventional osteosynthesis. In a sub-group the new osteosynthesis material was coated by plasma immersion ion implantation to improve biocompatibility. After 3 weeks the animals were sacrificed and the fracture healing was examined fluorescence-microscopically and histologically. In biomechanical testing it was proven that an osteosynthesis with 3 clips guaranteed
Oral Presentations/O47. Other IV the same torsion and bending stability high-significantly as with 2 mini plates. Due to their superelasticity by the shape memory efffect the clips however showed superiory over the conventional material concerning gaping. The histological evaluation showed that using the clips a primary fracture healing could be obtained. Coated clips exhibited thereby a better a osseointegration. The accomplished investigations show that this new osteosynthesis material can be used in the treatment of fractures of the facial skeleton. The biomechanical properties of that new osteosynthesis material show superiority over conventional methods.
[-O-~-]
MINIPLATE OSTEOSYNTHESIS WITH FOUR DIFFERENT SYSTEMS IN SHEEP
85 cases. In children there were more advantages because of the facial growth that is not affected with the fixation. In adults we opted in used resorbale material in fractures with no or minimal muscle influence in the estability. The complications observed were no related with resorbable material. More patients, more and extensive follow-ups is needed. References
[1] Ricalde P, Posnick JC. Degradation rate of delta (resorbable) internal fixation: report of two cases. J Oral Maxillofac Surg. 2004 62(2):250-5. [2] Norholt SE, Pedersen TK, Jensen J. LeFort I miniplate osteosynthesis: a randomized, prospective study comparing resorbable PLLA/PGA with titanium. Int J Oral Maxillofac Surg 2004 245-52.
R. Gutwald, R. SchSn, N.-C. Gellrich, M. Metzger, J. Kuschnierz, N. Weyer, R. Schmelzeisen. Department of ©ral and Maxillofacial
047. Other IV
Surgery, University of Freiburg, Germany The purpose of this investigation was to evaluate the influence on bone healing following osteosynthesis in the mandible of sheep with four different 2.0 miniplate systems. ST = Miniplates with Self-Tapping Screws. The screws were inserted manually after predrilling. SDF = Miniplates with Self-Drilling-Forming Screws. The screws, which formed their own thread into the bone, were inserted manually without predrilling. SDT-L = Self-Drilling-Tapping-Locking. The screws had a drill-like tip and a separate selftapping shaft. A special thread beneath the screw head was designed to lock into corresponding threaded plate holes. They were inserted with a special micro-motor-machine. ST-L = SelfTapping-Locking. The screws had also a thread beneath the screw head in order to lock into the plate holes. The screws were inserted manually after predrilling. In 24 sheep a standardised osteotomy was performed at the right premolar space. Osteosynthesis was performed with one of the above mentioned systems. Sacrification time points were at 4 and 8 weeks. After computer-tomography and assistance of a Navigationsystem the callus formation was measured. Histological analysis was performed at each osteotomy. After 4 and 8 weeks the highest callus formation was seen by the SDF-System followed by the ST- and SDT-LSystem. The Locking-System ST-L showed the lowest callus formation. In relation to the osteotomy gap the lowest percentage of new bone formation after 4 weeks was observed with the ST-, SDF- and SDT-LSystems whereas the highest rate of bone formation was seen by the ST-L-System. After 8 weeks an increase of bone formation within the ST-, SDF- and SDT-L-Systems could be observed, coming up to comparable values as the ST-L-System. The Self-Tapping-Locking-System showed the highest stability. Therefore the clinical use of this system in difficult cases should be supported.
[-0--'~
THE USE OF POLYLACTIC IMPLANTS AND PLATES (DELTA SYSTEM - LEIBINGER) IN ORAL AND MAXILLOFACIAL TRAUMA: A PRELIMINARY REPORT
EB. Mariani, L.E.C. Pagotto, A.R.S. Colucci, L.C. Manganello-Souza.
Associa~o Brasileira de OdontologiaABO Sec~o S~o Paulo, Hospital Municipal de Urg#ncias, Guarulhos, Brazil The purpose of this study was to evaluate and report our initial experience with a resorbable fixation system in maxillofacial trauma. The specific goals were to evaluate the stability, complications, advantages and disadvantages of the use of resorbable. From January 2004 to January 2005 we operated 15 cases of facial fractures including 4 children and 11 adults from 4 to 53 years of age. Children were treated with a single 1.7 mm plate. The adults fractures evolved were 4 blow-out orbital floor fractures, 5 zigomatic fractures, 2 LeFort II fracture. Blowout fractures were treated with resorbable mesh for orbital floor reconstruction. Zigomatic fractures and LeFort II fractures were treated with fixation in two points with 2.2 mm resorbable plate. We observed 1 case of superficial infection in angle mandibular fracture in a 7 years old child with Congenital Acquired Immunodefiency Syndrome, which presented a bilateral mandibular fracture. It was used Clindamicine 600 mg/day for 10 days to treat with good result. The others cases presented a good healing of the mandibular fractures with no mobility after a mean of 8 months post-operatively. In adult cases we observed one case of post-operative diplopia in very high supra-version, and the patient opted for no new surgical intervention. In one case of LeFort II fracture we observed what we considered a high level of maxillary mobility and opted for 10 days of maxillo-mandibular immobilization with successful result. Resorbable plates and mashes bring a good result in maxillofacial trauma in selected
•G-•'-•
HISTOLOGICAL EVALUATION OF DERMIS GRAFTS FOLLOWING DISCECTOMY IN THE RABBIT CRANIOMANDIBULAR JOINT
G. Dimitroulis 1 , J. Slavin 2. Departments of 1Special Surgery and
2Anatomical Pathology, St. Vincent's Hospital Melbourne, The University of Melbourne, Australia The purpose of this study is to determine the histological fate of the full thickness skin graft when placed into the temporomandibular joint using a rabbit model. Fourteen New Zealand white rabbits were used and divided into 3 groups. Two rabbits were used as controls (Group A) whereby a sham operation was undertaken. In six rabbits (Group B) the joint capsule of the left craniomandibular joint (CMJ) was surgically breached and the wound was repaired. The remaining six rabbits (Group C) also had the same surgical procedure to the left CMJ but with the interpositional placement of a full thickness skin graft which was taken from the skin of their necks. All grafts were placed above the head of the condyle and firmly secured to the surrounding tissues with non-resorbable sutures. The rabbits were sacrificed at 1, 3 and 5 months following surgery and the left CMJ's were histologically prepared and examined under light microscopy. The interpositional skin graft in all experimental animals (Group C) were found adjacent to the condyle on the lateral aspect rather than above the condylar head where it was originally sutured in place. Significant atrophy and reduction in the number and size of the skin appendages such as sweat glands and hair follicles was found within the grafted skin of all experimental animals compared to normal skin. All the grafts demonstrated evidence of epidermoid inclusion cysts. The full thickness skin graft may not be a suitable interpositional material for the TMJ because of the high risk of epidermoid cyst formation and the propensity for lateral displacement of the graft even when sutured into the appropriate intra-articular position.
[O4•
THE ROLE OF INTERLEUKIN (IL)-II~, IL-6 AND IL-8 IN PATHOGENESIS OF ODONTOGENIC CYSTS
K. Isik 1 , H. Ataoglu 2 , S. Haliloglu 3. 1Oral and Maxillofacial Department,
Selcuk University, Faculty of Dentistry, Konya, Turkey; 2Oral and Maxillofacial Department, Selcuk University, Faculty of Dentistry, Konya, Turkey; 3Biochemistry Department, Selcuk University, Faculty of Veterinary, Konya, Turkey, Oral and Maxillofacial Department, Baskent University, Faculty of Dentistry, Konya, Turkey The purpose of this study was to determine IL-11-~, IL-6 and IL-8 levels in odontogenic cyst fluids and, if exists, to find that whether the size, location and type of the cyst has an effect on the type and amount of ILs. Cystic fluids aspirated from 15 radicular, 7 dentigerous and 4 keratocysts were subjected to enzyme immuno assay test to determine IL-11-~, IL-6 and IL-8 levels. According to our results, there was no relationship between the IL levels and location or size of the lesions (p>0.05). On the other hand, when the IL types were compared, it was found that smaller cysts had less IL-11-~than IL-8 and larger cysts had less IL-11-~than IL-6 and IL-8 (p<0.01). When keratocysts were evaluated, there was no significant correlation between IL types (p>0.05). In dentigerous cysts, IL-11-~was significantly less than IL-6 and IL-8. In radicular cysts, IL-11-~was again less than IL-8 (p<0.01). IL-11-~, IL-6 and IL-8 should have an effect in