Hideto Saijo

Maxillofacial reconstruction using custom-made artificial bones fabricated by inkjet printing technology

Ideally, artificial bones should be dimensionally compatible with deformities, and be biodegradable and osteoconductive; however, there are no artificial bones developed to date that satisfy these requirements. We fabricated novel custom-made artificial bones from α-tricalcium phosphate powder using an inkjet printer and implanted them in ten patients with maxillofacial deformities. The artificial bones had dimensional compatibility in all the patients. The operation time was reduced due to minimal need for size adjustment and fixing manipulation. The postsurgical computed tomography analysis detected partial union between the artificial bones and host bone tissues. There were no serious adverse reactions. These findings provide support for further clinical studies of the inkjet-printed custom-made artificial bones.

Evaluation of 15 mandibular reconstructions with Dumbach Titan Mesh-System and particulate cancellous bone and marrow harvested from bilateral posterior ilia

This study reports on 15 mandibular reconstructions using the Dumbach Titan Mesh-System and particulate cancellous bone and marrow harvested from bilateral posterior ilia. All cases showed segmental defects. Eleven cases involved patients with malignant tumor. Six patients had received irradiation of 40-50 Gy. Reconstructions were performed immediately in 1 patient and secondarily in the remaining 14 patients. In 13 cases, mandibles were successfully reconstructed. Of these 13 patients, 9 reconstructions were completed without complications, whereas the other 4 cases showed complications. In 2 cases, reconstruction failed completely. Overall success rate was 87%. Statistical analysis revealed the extent of mandibular defect, but not malignancy of the original disease or radiotherapy of <or=50 Gy, as a significant factor in the occurrence of postoperative complications. Although no significant correlation was identified, cases in which mandibular continuity was lost at the time of reconstruction tended to show a higher postoperative complication rate. These results suggest that for the management of patients with malignant disease, resected mandible and soft tissue should be properly reconstructed using the metal plate and soft tissue flap at the time of cancer ablation surgery to reduce postreconstructive complications. Preoperative fabrication of the titanium mesh using a 3-dimensional skull model is expected to improve surgical outcomes.

A novel method for designing and fabricating custom-made artificial bones

Artificial bones are useful for tissue augmentation in patients with facial deformities or defects. Custom-made artificial bones, produced by mirroring the bone structure on the healthy side using computer-aided design, have been used. This method is simple, but has limited ability to recreate detailed structures. The authors have invented a new method for designing artificial bones, better customized for the needs of individual patients. Based on CT data, three-dimensional (3D) simulation models were prepared using an inkjet printer using plaster. The operators applied a special radiopaque paraffin wax to the models to create target structures. The wax contained a contrast medium to render it radiopaque. The concentration was adjusted to achieve easy manipulation and consistently good-quality images. After the radiopaque wax was applied, the 3D simulation models were reexamined by CT, and data on the target structures were obtained. Artificial bones were fabricated by the inkjet printer based on these data. Although this new technique for designing artificial bones is slightly more complex than the conventional methods, and the status of soft tissue should also be considered for an optimal aesthetic outcome, the results suggest that this method better meets the requirements of individual patients.

Clinical presentation of epignathus teratoma with cleft palate; and duplication of cranial base, tongue, mandible, and pituitary gland.

A 2-day-old girl was diagnosed with an oral epignathus teratoma and an uncommon combination of orofacial malformations including cleft palate; tongue, mandible, cranial base, cervical vertebrae, lower lip, and pituitary gland duplications; and fistula of the glabella and lower lip. Computed tomography revealed that the mass within the nasal cavity had tooth-like calcifications and protruded into the nasopharynx and oral cavity. It was implanted on the anterior wall of the body of the sphenoid bone and was accompanied with mandibular duplication. Magnetic resonance imaging detected duplication of the pituitary gland and confirmed the absence of intracranial communication of the nasopharyngeal mass. The teratoma did not cause respiratory obstruction; however, the patient required continuous nasogastric tube feeding. Usually, an epignathus teratoma is associated with few midline defects and can be corrected with multiple interventions at different time points. The current study describes the surgical procedure comprising excision of the tumor along with reconstructive surgeries of the mandible, tongue, and fistulae undertaken when the infant reached 7 months of age. The cleft palate was repaired at 18 months of age using the Kaplan buccal flap method. Histopathologic examination confirmed a grade 0 teratoma covered with keratinized skin and containing pilosebaceous and sweat glands, adipose tissue, and smooth muscle. The long-term success of this intervention was determined at the follow-up examination conducted at 3 years of age, with no signs of the teratoma recurrence observed.

Evaluation of Mandibular Hypoplasia in Patients With Hemifacial Microsomia: A Comparison Between Panoramic Radiography and Three-Dimensional Computed Tomography

Objective To compare the accuracy of three-dimensional computed tomography (3D-CT) and panoramic radiography in the evaluation of mandibular hypoplasia in patients with hemifacial microsomia (HFM). Design Retrospective study of imaging data. Setting Images selected from the archives of the University of Tokyo Hospital. Subjects Twenty patients with unilateral HFM who had undergone both panoramic radiography and 3D-CT in the same period. Method Mandibular deformities were classified according to the Pruzansky classification; eight patients had Grade I deformity and 12 patients had Grade II deformity. Ramus heights were measured on both panoramic radiographs and 3D-CT. Main outcome measures Magnification in panoramic radiographs and extent of mandibular asymmetry as estimated by the affected/unaffected side ratio based on two methods were examined. The Pearson product-moment correlation coefficient was used to estimate correlations between parameters. Results The magnification of ramus heights on panoramic radiographs showed large variations in Grade II patients. The affected/unaffected side ratio estimated by the two methods showed a strong correlation in Grade I patients (correlation coefficient 0.99; p < .0001). Conversely, a weak correlation was seen in Grade II patients (correlation coefficient 0.77; p = .0036), and affected/unaffected side ratios from panoramic radiographs were both over- and underestimated. Conclusions The accuracy of evaluation using panoramic radiography was fairly reliable in Grade I patients. Conversely, accuracy was poor in Grade II patients, and evaluation using 3D-CT seems preferable. The combination of two methods with careful consideration is recommended for clinical applications.

Metastasis of Hepatocellular Carcinoma into the Mandible with Radiographic Findings Mimicking a Radicular Cyst: A Case Report

INTRODUCTION Hepatocellular carcinoma (HCC) is a common neoplasm worldwide, with more than half of the tumors associated with regional metastasis. Extrahepatic metastasis is also common, and the most frequently affected sites are the lungs, abdominal lymph nodes, diaphragm, and bone. However, HCC metastasis to the mandible is rare, with approximately 50 cases reported in the literature. METHODS In this report, we describe a case of HCC metastasis to the mandible at the apex of #18 root in a 62-year-old man. This patient had already been diagnosed with metastasis to pancreatic caput lymph node. The radiographic features of the mandible resembled radicular cyst and did not show typical findings of malignancy. RESULTS Under the first diagnosis of radicular cyst, root canal treatment was initially performed, and then surgical treatment of the removal of the cystic lesion and #18 extraction were performed. Finally, the lesion was diagnosed as HCC metastasis from pathological examination. Consequently, he received constitutional chemotherapy in the hepatitis unit and is now in remission. CONCLUSION This case shows the importance of considering the differential diagnosis of malignancy.

Submucous cleft palate: variations in bony defects of the hard palate

We have analysed bony defects of the hard palate in patients with submucous cleft palate to find out whether velopharyngeal insufficiency (VPI) is dependent on the extent of these defects. We evaluated the maxillofacial structures associated with cleft palate by 3-dimensional computed tomography (CT) in 23 children diagnosed with submucous cleft palate. Bony defects of the hard palate were divided into Type I, defined as absent posterior nasal spine (n=12), Type II, V-shaped bony notch (moderate, n=7), and Type III, as bony defect extending into the incisive foramen (severe, n=4) defects, respectively. VPI was found in 10, 3, and 4 patients, respectively. Neither VPI nor the degree of bifid uvula was significantly associated with the types of bony defects.

Treatment of ankylosed maxillary central incisors by single-tooth dento-osseous osteotomy and alveolar bone distraction

When tooth ankylosis occurs in growing children, the ankylosed tooth fails to erupt and gradually positions itself below the occlusal plane. This causes functional and esthetic problems, and orthodontic treatment is often impossible. To clarify this problem, we developed a new treatment protocol for the movement of ankylosed teeth. This consists of single-tooth dento-osseous osteotomy and alveolar bone distraction using orthodontic multibracket appliances. A special distraction device is not required, thus reducing the burden to patients. Two cases in which an ankylosed maxillary central incisor was successfully treated with this protocol are presented.

Cyclooxygenase-2 activity is important in craniofacial fracture repair.

The aim of this study was to examine the effect of cyclooxygenase (COX)-2 on bone repair after craniofacial fracture in mice. A 4-mm fracture was created in the parietal bone of 8-week-old male COX-2 wild-type (COX-2(+/+)) and knockout (COX-2(-/-)) mice. Ribonucleic acid was extracted from the fractured bone and analysed. For morphological and histological analysis, the mice were killed 8 and 12 weeks after treatment, and sections were prepared. Three-dimensional computed tomography was performed, and the sections were stained with hematoxylin-eosin for histological examination. Expression of COX-2 messenger ribonucleic acid was induced in COX-2(+/+) mice, but not in COX-2(-/-) mice. Ossification at the fracture site was almost complete 12 weeks after fracture in COX-2(+/+) mice. In COX-2(-/-) mice, incomplete union had occurred at the fracture site. In both types of mice, the fracture site contained no cartilaginous tissue, and the callus formed from the periosteal side. These results suggest that COX-2 plays an important role in craniofacial fracture repair and that COX-2-selective non-steroidal anti-inflammatory drugs might interfere with fracture repair of the membranous viscerocranium in the clinical setting.

Preclinical and clinical research on bone and cartilage regenerative medicine in oral and maxillofacial region

Abstract Recently, there have been remarkable advances in regenerative medicine, and almost all disorders of the oral and maxillofacial region could be research targets of regenerative medicine. Meanwhile, treatment in this region has been well established using biomaterials, prostheses, and microsurgery. Therefore, to surpass such a conventional approach as an alternative, regenerative medicine should take an approach of being less invasive and/or more effective. In this report, we present our preclinical and clinical research on bone and cartilage regenerative medicine in the oral and maxillofacial region. Regarding bone regenerative medicine, we have tried to develop artificial bone that would maximize bone formation at the transplanted site, but would subsequently be replaced by autologous bone. We have made custom-made artificial bone (CT-Bone) using alpha-tricalcium phosphate (α-TCP) particles and an ink-jet printer, and have conducted clinical research and trials on 30 patients. To develop tissue-engineered cartilage with proper three-dimensional (3D) morphological form and mechanical strength, we have optimized the culture medium of chondrocytes and the scaffold. Following a preclinical study confirming efficacy and safety, we have conducted clinical research in three patients with nasal deformity associated with cleft lip and palate, and are now starting multicenter clinical research.