Autogenous bone graft and PRP for maxillary reconstruction

©ral P r e s e n t a t i o n s / ©20. R e c o n s t r u c t i v e S u r g e r y II

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ipslateral loading, contralateral loading, bilateral loading and oblique loading were applied on BMM. T test and variance analysis of SAS 6.12 was used. BMM consisted of buttress area and muscle area with different size. Double lag screws along biomechanical tract of mandible was designed for BMM fixation. Under four loading conditions, the stress of BMM was reasonable and well distributed, where the maximum stress was located in mandibular angle. The maximum stress of bone tissue, arounding lag screw and BMM abutment was significantly less than that of normal cancellous bone (t=-4.21208, p=0.0008<0.01). The design of digital model of biomechanics mandible was reasonable, which conformed to the biomechanical principle of mandible.

detailed postoperative control. Conventional X-ray and CT imaging consisting of a static single picture selection can miss decisive information which if neglected can lead to failures in orbital reconstruction. The application of the dynamic computer assisted modern imaging reduces this risk. It shows not only the individual anatomical situation but also the optimal result of the operation in advance. Computer aided preoperative imaging is a valuable tool in orbital surgery. It leads to a higher level of security during the operation and opens the door to a higher quality of patient care. In cases were anatomical structures which are needed for exact positioning of fragments or grafts are missing it is a mandatory prerequisite in combination with intraoperative navigation for an exact reconstruction.

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References

DEVELOPMENT OF COMPUTER-AIDED FUNCTIONAL EVALUATION SYSTEM FOR PATIENTS AFTER GLOSSECTOMY

N. Suzuki. Dept of Oral and Maxfllofacial Surgery, Showa University Dental Hospital, Tokyo, Japan The purpose of this study was to develop a computer-aided functional evaluation system for patients with tongue and mouth floor resection by comparing Magnetic Resonance Imaging (MRI) data with acoustic data. 3D MRI and acoustic measurement were employed for this study. The vowel /i/ was selected as the speech sample because its production requires the strongest tongue movement among five vowels. 3D MRI slices were taken at 5 mm intervals to analyse the vocal tract shape and area function (cross-section). Spectral peak frequencies of F1 and F2 from 300 to 500 Hz and from 1500 to 3000 Hz were measured. Ten patients were investigated by 3D MRI and compared with 5 normal subjects. Meanwhile, 16 patients and 10 normal subjects were measured acoustically. The following results were obtained: (1) Vocal tract shape was associated with the extent of resection (partial-, hemi-, subtotaland total-glossectomy) and reconstructive procedure (several kinds of flaps). (2) The acoustic features of severely resected patients exhibited (a) higher F1 than normal, (b) two peaks in the 1500 to 3000Hz range, and (c) lower F2 than normal. In conclusion, to evaluate results after tongue and mouth floor resection, the locations of the F1 and F2 ranges and the narrow area function of the central portion of the palate (around the first molar teeth) are proposed as important cues. From these results the possibility of development of computer-aided functional evaluation system for Iossectomee is suggested. References

[1] Bear T, Gore JC, Gracco LC,Nye PW:Analysis of vocal tract shape and dimentions using magnetic resonance imaging: Vowals. J Acoust Soc Am, 90: 799-828, 1991. [2] Georgian DA, Logemann JA, Fisher HB: Compensatory articulation patterns of a surgically treated oral cancer patient. J Speech Hear Disord, 47: 154-159, 1982. [3] Imai S, Michi K: Articuratory function after resection of the tongue and floor of the mouth: palatometric and perceptual evaluation.J Speech Hear Res, 35: 68-78, 1992. [4] H. Nishimoto, M. Akagi, T. Kitamura, and N. Suzuki: Analysis of transfer functions for defoemed vocal tract models after tongue and mouth floor resection. TECHNICAL REPORT OF IEICE. TP2002-58:5-10 (2002-07).

[ - 0 - - ~ - ~ DYNAMIC IMAGE ANALYSIS IN ORBITAL DEFORMITIES A MANDATORY PREREQUISITE FOR RECONSTRUCTIVE SURGERY

B. Sinikovic, A. Schramm, D. Grotzer, N.-C. Gellrich. Department of Oral and Maxillofacial Surgery, Medical University of Hannover, Hannover, Germany The orbit is one of the most delicate regions of the facial skeleton to be reconstructed. Although computer tomography (CT) has become the predominant diagnostic investigation in this field it is often used in a limited way. Still several reasons like posttraumatic atrophy of the orbital fat or neural disorders are often blamed for suboptimal clinical results. The purpose of this presentation is to focus on the reconstruction of the orbital walls as the main factor of surgical success. Clinical cases showing the major problems of the orbital surgery and preoperative planning are presented. A comparison is made between conventional pre- and postoperative diagnostics and computer assisted dynamic image analysis using DICOM files of CT scans with appropriate analysis software. This technique allows additional intraoperative guidance and

[1] Advanced procedures in reconstructive and function-preserving orbital surgery by computer-assisted presurgical planning (CAPP) and computerassisted surgery (CAS) Zizelmann C, Schramm A, Schon R, Ridder G J, Maier W, Schipper J, Gellrich NC HNO. 2004 Nov 12; e-publication DOI: 10.1007/s00106-004-1178-x. [2] Navigation-aided reconstruction of medial orbital wall and floor contour in cranio-maxillofacial reconstruction. Schmelzeisen R, Gellrich NC, Schoen R, Gutwald R, Zizelmann C, Schramm A. Injury. 2004 Oct;35(10):955-62. [-0--~--~ BIORESORBABLE POLY-L/DL-LACTIDE [P(L/DL)LA 70130] PLATES ARE RELIABLE FOR REPAIRING OF LARGE INFERIOR ORBITAL WALL BONY DEFECTS: A PILOT STUDY J. AI-Sukhun, R. Kontio, C. Lindqvist. Departments of Oral and

Maxillofacial Surgery, Institute of Dentistry, Helsinki University Central Hospital, Helsinki University, Finland The purpose of this study was to share our clinical experience on the use of bioresorbable poly-L/DL-Lactide implants [P(L/DL)LA 70/30] to repair, large, inferior orbital wall defects and to evaluate whether P(L/DL)LA 70/30 implants adequately support the orbital soft tissue contents. Ten patients, who suffered pure orbital blow-out fractures, with 2-3cm, bony defect in the inferior orbital wall, took part in the study. The inferior orbital wall was explored via subciliary approach. After repositioning of orbital content, each inferior orbital wall was reconstructed using a round plate of P(L/DL)LA 70/30 (PolyMax, Synthes, Oberdorf, Switzerland). CT and MRI coronal sections were undertaken before the operation and two and 36 weeks postoperatively. The MRI studies showed no abnormal tissue, foreign body, reactions in the orbital region. The material showed adequate strength to stabilize bone segments during the critical period of bone healing. The bone healing seems to take place along the bone fragments. The clinical outcome was excellent in 8 out of the 10 cases (80%). At the end of the study, only one patient had mild enophthalmos. Bioresorbable P(L/DL)LA 70/30 implants are safe and efficient for the repair of large defects (2-3cm) in the inferior orbital wall. It seems that this is the first reported biodegradable material, in the literature, to promote bone healing along the bone fragments of the inferior orbital wall.

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AUTOGENOUS BONE GRAFT AND PRP FOR MAXILLARY RECONSTRUCTION

G.C. Beltr~o, A.T. Abreu, R.G. Beltr~o, N.E Finco, C.F. Finco. PosGraduation Program in Oral and maxillofacial Surgery and Traumatology,

University of Dentistry, Pontificia UnJversJdade Cat6ilca of Rio Grande do Sul, Porto Alegre/RS, Brazil The bone loss in maxilla often occurs by a sort of causes such as periodontitis, trauma, infection and pour treatments. Low bone quality is another problem that increases the early loss and difficult the implant treatment. In Brazil there's a lot of patients that needs total maxillary reconstruction. Iliac bone graft is the most used in this kind of procedure due to its characteristics: bone quality, low morbidity, quantity and presence of steam cells. Platelet Rich Plasma (PRP) has been used as a growth factors source for bone grafts. The PRP increases bone and soft tissue regeneration, facilitate bone modeling and stimulate steam cells. The porpose of this study is to demonstrate a surgical protocol for maxillary recontruction. The Bucomaxillofacial service of Sao Lucas Hospital has been used iliac bone graft with PRP for alveolar reconstruction with good results. For this study were selected ten toothless patients (mean age 50.6 years) that needed maxillary reconstruction for implants rehabilitation. All patients sign up an informed consent. They were submit

Int. J. Oral Maxillofac. Surg. 2005; 34 (Supplement 1): $ 1 - $ 1 8 1

40 to the same surgical protocol: appositional bone graft in anterior maxilla covered with PRP and bilateral "sinus lift" procedure with particulate bone graft and PRE No biomaterials were used. After four or six months the patients were submitted to implants placement procedure. The implants used were 3i osseotite® and the implants number was 6-8 per patient (mean 6.8) and all implants were placed in bone grafted areas. The results of this study shows that all patients could have implants placed in maxilla after 4-6 months. The postoperative problems were minimal as little pain and small bone graft exposure. No infection was registered. After 4 months of implant placement surgery, none implant was lost. The authors conclude that iliac bone graft is the most indicated for maxillary bone graft reconstruction and PRP allows better results as well as treated surface implants.

[-O-~'-~ REPAIR OF MANDIBULAR CONTINUITY DEFECTS USING MINIPLATES AND AUTOLOGOUS PLATELET RICH PLASMA IN DOGS R.F. Elgazzar, A.I. Abdelhady, G.E. Elsayyad, I.E. Megahed. Oral and Maxillofacial Surgery Department, Faculty of Dentistry, Tanta University, Tanta, Egypt Reconstruction of the mandible after continuity resection poses a challenge in that a functionally as well as an aesthetically pleasing result is required. New methods of maxillofacial reconstruction include the use of bone engineering techniques and platelet rich plasma (PRP). The objective of this study was to investigate the effect of PRP on the healing of non-critical mandibular bone defects in dogs. Segmental bone defects of 1 cm size were created in the mandibular molar area of 10 Balady Dogs. Bony gaps were bridged with titanium miniplates. The dogs were divided randomly into 2 groups, in the experimental group (group I), the bone defects were filled with autologous blood clot and the pre-made PRP gel. In the control group (group II), the bone defects were only filled with blood clot. All dogs were killed after 12 weeks and specimens were evaluated radiographically and Histopathologically. The results of this study showed that, filling of the bony defects with hard callus and maturation of bone was prominent in the PRP treated group, compared to the control group. Using PRP enhances bone healing and maturation and improves the repair of mandibular non critical segmental bone defects.

O21. Distraction Osteogenesis I

[-O2"~-1 THE CASE DEPENDANT ALVEOLAR RECONSTRUCTION IN ORAL IMPLANTOLOGY: CRITERIAS FOR PREFERRING BETWEEN ALVEOLAR DISTRACTION OSTEOGENESIS AND AUTOGENOUS BONE GRAFTING S. Yilmaz, S. Basa. Dept.of Oral and Maxillofacial Surgery, Faculty of

Dentistry, Marmara University, Istanbul, Turkey Alveolar distraction osteogenesis (ADO) and autogenous bone grafts are widely used techniques in oral reconstructions prior to implant placement. We try to determine in which defects and conditions alveolar distraction osteogenesis and bone grafting suits best as an osseous regenerative procedure. Patients with alveolar defects occurred after teeth extraction, severe periodontal disease, benign or malignant jaw tumor resections, facial trauma and atrophic edentulous ridges were treated. Rigid and non-rigid alveolar distractors of different brands were used in vertical augmentation of these defects. As distractors were placed, the devices were activated after 7 days until the desired vertical height was reached. The consolidation period for cases was set to be three months and following dental implants were placed in the distracted alveolar bones. Mandibular symphis, ramus regions and maxillary tuberosities were main bone donor sites for harvesting block grafts. Block grafts were secured with cortical screws. Mixture of b-tricalcium phosphate particles, platelet rich plasma and autogenous particulate bone was introduced under cortical blocks. ADO proceeded without any complication. A newly formed bone and augmentation of intraoral soft tissues was observed during removal of devices. Adequate vertical augmentation was achieved by ADO. The vertical distraction provided placement of the longest implants in the anterior mandible. After grafting procedures no complication occurred in donor and host sites. Only one patient experienced flap exposure which

was closed with a secondary intervention. Minimal postoperative donorside morbidity was observed in osteotomized symphises and ascending rami. Infection and flap exposure is not seen in none of the ADO cases Horizontal augmentation was provided mainly by onlay grafting whereas the vertical ridge augmentation was made by ADO. Bone grafting in means of onlay ridge augmentation provides better bucco-lingual augmentation rather than vertical ADO. Soft tissue closure is more difficult and generally the doomed grafted ridge is likely to flap exposure. The reconstructive technique should be selected according to defect size and patient compliance. ADO and bone grafting have many advantages and disadvantages upon each other.The criterias for choosing the ADO or grafting is discussed in the presentation with various cases.

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USE OF AN ALVEOLAR DISTRACTION DEVICE FOR REPOSITIONING THE MAXILLARY SEGMENT TO CORRECT ASYMMETRY OF THE MAXILLOMANDIBULAR COMPLEX

K. Yamauchi, K. Funaki, T. Kanno, W. Ariyoshi, T. Takahashi. Kyusyu Dental College Science of Physical Functions, Dept. of Oral and Maxillofacial Surgery, Div. of Maxillofacial Reconstructive Surgery, Japan In patients with hemifacial microsomia, distraction osteogenesis is an acceptable treatment modality for correcting the facial asymmetry according to a considerable number of clinical report. However, disadvantages of distraction osteogenesis are also documented, including difficulty correcting both the maxilla and mandible simultaneously and the development of malocclusion during or after the distraction osteogenesis. In this study, we use an alveolar distraction device on the maxilla and perform a conventional mandibular osteotomy; then, the maxilla and mandible are distracted simultaneously to obtain an appropriate occlusion for correcting the facial asymmetry. Under general anesthesia, an incision is made in the upper buccal sulcus from the canine to the first molar on each side. The periosteum is elevated along the anterior aspect of the maxilla, from the piriform aperture to the malar area. The nasal mucoperiosteum is elevated at the lateral maxillary wall only, preserving the nasal floor and anterior nasal spine. A complete horizontal osteotomy is then made in the maxilla at the level of the nasal floor using a reciprocating saw. The pterygomaxillary junction is freed using a bone spreader at the zygomatic buttress on the affected side only. While spreading the segment on the affected side, the nasal spine and septum are freed at the same time. On the unaffected side, the pterygomaxillary junction is kept intact. After confirming the mobility of the maxillary segment, an intraoral alveolar vertical distractor (Martin, Tuttlingen, Germany) is fixed at the zygomatic buttress area of the affected side, and a hinged bone plate or miniplate is fixed to the zygomatic buttress of the unaffected side. Subsequently, we perform an intraoral vertical ramus osteotomy (IVRO), as described by Hall. After the mandibular osteotomy, rigid intermaxillary fixation (IMF) using soft wires and elastics is performed at the end of the operation. The mandible followed the maxillary changes, so that the facial profile was achieved via a three-dimensional change in elongation with medial rotation. In both cases, the facial asymmetry was greatly improved with horizontalization of the occlusal plane. This method achieves very acceptable functional and aesthetic results in a few weeks without the need for a complex osteotomy combined with a bone graft. Our technique is one treatment modality for correcting facial asymmetry in adults.

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THE USE OF AUTOGENOUS BONE GRAFTS ON THE TRANSPORT DISC ON ALVEOLAR DISTRACTION OSTEOGENESIS

M.M. Soares, E Guerra, L. Marinho, A. Safady. Osteogenesis Institute,

Brazil The use of distraction osteogenesis on atrophied alveolar bone is limited by the amount of bone available for the transport disc. The use of bone graft to improve the volume of the transport bone before the distraction has been reported; however it increases the time on the treatment and introduce another surgical procedure For this study 11 patients with severe maxillary atrophy were selected being four partially ant seven totally edentulous patients All the graft used were autogenous bone grafts, being the donor site the mandibular ramus. The atrophied alveolar areas were submitted to sinus graft and distraction osteogenesis on the anterior maxilla, with the horizontal osteotomy being extended to the sinus floor in order to transport the sinus floor and the graft to a