Utilization of desktop 3D printer-fabricated "Cost-Effective" 3D models in orthognathic surgery.

BACKGROUND: In daily practice, three-dimensional patient-specific jawbone models (3D models) are a useful tool in surgical planning and simulation, resident training, patient education, and communication between the physicians in charge. The progressive improvements of the hardware and software have made it easy to obtain 3D models. Recently, in the field of oral and maxillofacial surgery, there are many reports on the benefits of 3D models. We introduced a desktop 3D printer in our department, and after a prolonged struggle, we successfully constructed an environment for the "in-house" fabrication of the previously outsourced 3D models that were initially outsourced. Through various efforts, it is now possible to supply inexpensive 3D models stably, and thus ensure safety and precision in surgeries. We report the cases in which inexpensive 3D models were used for orthodontic surgical simulation and discuss the surgical outcomes. REVIEW: We explained the specific CT scanning considerations for 3D printing, 3D printing failures, and how to deal with them. We also used 3D models fabricated in our system to determine the contribution to the surgery. Based on the surgical outcomes of the two operators, we compared the operating time and the amount of bleeding for 25 patients who underwent surgery using a 3D model in preoperative simulations and 20 patients without using a 3D model. There was a statistically significant difference in the operating time between the two groups. CONCLUSIONS: In this article, we present, with surgical examples, our in-house practice of 3D simulation at low costs, the reality of 3D model fabrication, problems to be resolved, and some future prospects.

Surgical Orthodontic Treatment Involving Mandibular Premolar Extraction in Patient with Mandibular Retrusion Associated with Temporomandibular Joint Osteoarthritis.

Here, we report retention following surgical orthodontic treatment in a patient with vertical maxillary excess associated with temporomandibular joint osteoarthritis (TMJOA) and marked mandibular retrusion. The patient was a man aged 20 years 10 months who presented with the chief complaint of maxillary protrusion. The facial profile was of the convex type due to marked mandibular retrusion. In addition, the patient had a gummy smile. Intraoral findings revealed a Class II molar relation, +11 mm overjet, and 0 mm overbite. Mandibular dentition arch length discrepancy showed crowding of -2 mm, and the maxillary dentition showed a spaced arch of +5 mm. Panoramic radiographs confirmed flattening of the condylar head and proliferation of the bone margin. Cephalometric analysis of the skeletal pattern revealed that, horizontally, the maxilla was anterior and the mandible posterior; vertically, a dolichofacial pattern was noted. The anterior maxillary tooth axis was standard, but the anterior mandibular tooth axis showed labial inclination. Based on these findings, skeletal maxillary protrusion associated with TMJOA was diagnosed. Surgical orthodontic treatment comprised bilateral mandibular first premolar extraction with two-jaw surgery and genioplasty. Orthodontic treatment was performed with a multibracket system using a 0.22-slot pre-adjusted edgewise appliance. At 2 years and 11 months after initiation of treatment, the maxilla was transposed 6 mm upwards by orthognathic surgery and the mandible 17 mm anteriorly and 5 mm upwards by counterclockwise rotation. At 3 years and 10 months, the Pogonion was moved 6 mm anteriorly by genioplasty. At 4 years, orthodontic treatment was concluded on confirming satisfactory occlusion and improvement in facial features. At 2 years after completion of treatment, occlusion and the maxillofacial morphology remain stable, with almost no relapse. In addition, no temporomandibular joint disorder symptoms have occurred. Careful comprehensive follow-up observation will be continued.

Incidental findings during head and neck MRI screening in 1717 patients with temporomandibular disorders.

OBJECTIVE: Magnetic resonance imaging (MRI) plays an important role in the evaluation of temporomandibular disorders (TMDs). At our institution, we perform additional head and neck screening using head coils when performing MRI screening of the temporomandibular joint (TMJ) to detect lesions in areas other than the TMJ (lesions discovered by chance, or incidental findings; IFs) and to conduct a diagnosis of exclusion. The objective of this study was to determine the number and frequency of IFs detected during head and neck screening, according to sites and diseases. MATERIALS AND METHODS: The study evaluated 1717 patients with clinically suspected TMDs who underwent MRI of the TMJ. IFs were assessed on horizontal sections of images of the craniofacial region obtained by the short tau inversion recovery imaging technique. RESULTS: The patients undergoing MRI of the TMJ comprised 433 males and 1284 females. Among the patients, at least one IF was detected on images in 461 patients. The most common IF site was the maxillary sinus. Based on diagnostic imaging, there were 21 IFs (1.2%) associated with TMD symptoms, or for which an association with TMD symptoms could not be ruled out. CONCLUSIONS: Combination of conventional MRI imaging of the TMJ with craniofacial MRI screening may allow detection of lesions other than TMDs, thereby confirming the usefulness of MRI. Detection of IFs may require development of different therapeutic strategies than those for TMDs.

Mandibular Reconstruction with Free Vascularized Fibular Graft.

An iliac block graft is the most commonly used biomaterial for reconstruction following resection of the mandible. Its use has some disadvantages, however, including limitations on the amount of bone that may be harvested, and the subsequent increase in burden on the iliac bone. Therefore, recently, free vascularized fibular grafts have been used as an alternative in some cases. Here, we report the advantages of, and issues related to reconstruction using free vascularized fibular grafts observed at Tokyo Dental College Chiba Hospital. Eight patients undergoing mandibular reconstruction using free vascularized fibular grafts between January 2003 and January 2017 were investigated. Of these, 6 were men, and 2 were women. Age ranged from 38 to 74 years (average, 54 years). Primary diseases comprised malignant tumor in 3 patients, benign tumor in 3, and radiation osteomyelitis of the mandible in 2. The defects were classified as follows according to the CAT system (Condylar Head, Mandibular Angle, Mental Tubercle): 3 cases of Body, 2 of AT, and 1 case each of TT, ATTA, and CATT. The resection range of the mandible was 5-16 cm (average, 10 cm). The single barrel technique was used in 7 cases, and the double barrel technique in 1. In terms of the flap survival ratio, complete engraftment was achieved in 6 out of the 8 cases. Two cases of radiation osteomyelitis of the mandible, with necrosis caused by vascular breakdown after wound infection, were observed, however. While the advantages of mandibular reconstruction by this method include comparatively safe conditions and functional recovery, there were also some problems. It was inappropriate for cases of radiation osteomyelitis of the mandible; those where anti-inflammatory therapy was ineffective; and those where greater resection of the soft tissue was required. Further study is needed to clarify the criteria for selecting this procedure.

Utilizing a low-cost desktop 3D printer to develop a "one-stop 3D printing lab" for oral and maxillofacial surgery and dentistry fields.

BACKGROUND: In the oral and maxillofacial surgery and dentistry fields, the use of three-dimensional (3D) patient-specific organ models is increasing, which has increased the cost of obtaining them. We developed an environment in our facility in which we can design, fabricate, and use 3D models called the "One-stop 3D printing lab". The lab made it possible to quickly and inexpensively produce the 3D models that are indispensable for oral and maxillofacial surgery. We report our 3D model fabrication environment after determining the dimensional accuracy of the models with different laminating pitches (; layer thickness) after fabricating over 300 3D models. Considerations were made for further reducing modeling cost and model print time. MDCT imaging was performed using a dry human mandible, and 3D CAD data were generated from the DICOM image data. 3D models were fabricated with a fused deposition modeling (FDM) 3D printer MF-2000 (MUTOH) with a laminating pitch of 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm. Each 3D model was then subjected to reverse scanning to evaluate the modeling conditions and deformation during modeling. For the 3D image processing system, Volume Extractor 3.0 (i-Plants Systems) and POLYGONALmeister V2 (UEL) were used. For the comparative evaluation of CAD data, spGauge 2014.1 (Armonicos) was used. RESULTS: As the laminating pitch increased, the weight of the 3D model, model print time, and material cost decreased, and no significant reduction in geometric accuracy was observed. CONCLUSIONS: The amount of modeling material used and preparation cost were reduced by increasing the laminating pitch. The "One-stop 3D printing lab" made it possible to produce 3D models daily. The use of 3D models in the oral and maxillofacial surgery and dentistry fields will likely increase, and we expect that low-cost FDM 3D printers that can produce low-cost 3D models will play a significant role.

Postoperative Conversion Disorder in Elderly Oral Cancer Patient.

Conversion disorder is a condition in which psychological stress in response to difficult situations manifests as physical symptoms. Here, we report a case of postoperative coma due to conversion disorder in an elderly oral cancer patient. An 82-year-old woman was referred to Tokyo Dental College Chiba Hospital with a mass lesion on the tongue. A biopsy revealed a well-differentiated squamous cell carcinoma. Surgical treatment was performed for the tongue carcinoma and tracheotomy for management of the airway. On postoperative day 5, the patient exhibited loss of consciousness (Glasgow Coma Scale: E1, VT, M1; Japan Coma Scale: III-300). The patient's vital signs were all normal, as were the results of a full blood count, brain-CT, MRI, and MRA. Only the arm dropping test was positive. Therefore, the cause of the coma was diagnosed as conversion disorder. Seven hours later, the patient showed a complete recovery.

Analysis of Needlestick and Similar Injuries over 10 Years from April 2004 at Tokyo Dental College Chiba Hospital.

Here we investigated needlestick and similar injuries reported over a 10-year period between April 2004 and March 2014. The purpose of this study was to prevent recurrence and reduce the incidence of such injuries at Tokyo Dental College Chiba Hospital. The Division of Medical Risk Management at Chiba Hospital anonymized the data to protect personal information prior to analysis. A total of 213 injuries occurred over the 10-year period investigated, but the number of cases decreased yearly. Many cases involved dental undergraduate students and dentists, followed by trainee dentists, students at the school of dental hygiene, nurses, dental hygienists, and cleaners. Suture needles, followed by injection needles, were the top two most common injury-causing instruments, contributing to approximately 50% of the total number of such cases. Many injection needle injuries occurred during tidying up, while those caused by suture needles occurred during dental treatment. Taken together, these findings suggest the importance of strict adherence to guidelines provided in safety manuals on error-free procedures and handling of instruments. Improvement in the ability to sense potential risk is essential if such injuries are to be avoided.

Narrow-band imaging system with magnifying endoscopy for early oral cancer.

It is often difficult to detect early oral cancer due to the specificity of the oral mucosa structure. The aim of this study was to investigate the potential of narrow band imaging (NBI) as an effective and non-invasive diagnostic tool in early oral cancer and other oral diseases. A magnifying endoscopy system manufactured by Olympus Corporation was used. A total of 121 subjects were included in the study. Subepithelial capillary loops were identified and categorized according to the classification of Inoue, with healthy mucosa graded as Type I or II, and that showing evidence of cancer-induced morphological change as Type III or IV. Sensitivity and specificity for the identification of oral cancer were estimated at 92.3% and 88.2%, respectively. Examination under a microscope with H&E staining and immunostaining for CD34 revealed dilation and extension of the capillaries in epithelial dysplasia, in addition to thickening of the epithelial layer. The present results indicate that use of NBI in conjunction with conventional magnifying endoscopy has great potential as an effective and non-invasive diagnostic tool in the early detection of oral cancer.

Accidental ingestion or aspiration of foreign objects at Tokyo Dental College Chiba Hospital over last 4 years.

The aim of this study was to investigate cases of accidental ingestion or aspiration occurring at Tokyo Dental College Chiba Hospital over the last 4 years in order to determine how the incidence of such events could be reduced. Forty cases of accidents occurring at our hospital over a 4-year period commencing in 2008 (representing 27% of the total number of accidents) included accidental ingestion in 39 patients and aspiration in one. Most of these accidents occurred during the removal or placement of restorations or prosthetics, and the ingested objects were mostly crowns and inlays. Accidental ingestion or aspiration occurred more frequently in the right molar region and when procedures were conducted by practitioners with less than 1 to 7 years of experience, and especially 1 to 3 years only. A higher rate of such accidents was observed in male patients in their 50s to 70s. The conventional safety procedures developed by the Medical Risk Management Team should be adhered to wherever possible. Furthermore, we propose the following measures based on the present results: accident prevention training for students and clinical trainees; improvement of the in-hospital manual; personal coaching for those breaching the guidelines of the safety manual; and raising awareness of the need for greater care in preventing incidents of accidental ingestion or aspiration at the Tokyo Dental College Chiba Hospital.

Bisphosphonate-related osteonecrosis of jaw (BRONJ) in Japanese population: a case series of 13 patients at our clinic.

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) affects quality of life and is an important problem for dentists. A Japanese position paper on BRONJ was published in 2010. The purpose of this study was to review clinical data on the treatment of BRONJ obtained at the Clinic of Oral and Maxillofacial Surgery, Tokyo Dental College, Chiba Hospital to further our understanding of this disease. A total of 13 patients (6 men and 7 women) were included. All the patients included in this study had received Bisphosphonate (BP) therapy and had BRONJ. Five of them (38.5%) had received oral BP therapy for osteoporosis, while the remaining 8 (61.5%) had received parenteral BP therapy for bone metastases from breast or prostate cancer. Osteoporosis patients were treated with risedronate or alendronate. Breast or prostate cancer patients were treated with zoledronate. Two patients with rheumatoid arthritis were treated with corticosteroid. Three patients had diabetes mellitus. Eleven patients were treated with antibiotics, while 5 underwent surgical treatment. Discontinuation of BP was recorded in 7 patients during dental treatment. Sequestration was observed in 6 patients during an 11-month follow-up. Eventually, healing and improvement of the oral mucosa were observed in 3 patients. The current standard treatment for BRONJ does not always provide good results. It is necessary to accumulate further clinical data to establish more effective treatment strategies for BRONJ.

Analysis of copy number abnormality (CNA) and loss of heterozygosity (LOH) in the whole genome using single nucleotide polymorphism (SNP) genotyping arrays in tongue squamous cell carcinoma

Chromosomal loss of heterozygosity (LOH) is a common mechanism for the inactivation of tumor suppressor genes in human epithelial cancers. LOH patterns can be generated through allelotyping using polymorphic microsatellite markers; however, owing to the limited number of available microsatellite markers and the requirement for large amounts of DNA, only a modest number of microsatellite markers can be screened. Hybridization to single nucleotide polymorphism (SNP) arrays using Affymetarix GeneChip Mapping 10 K 2.0 Array is an efficient method to detect genome-wide cancer LOH. We determined the presence of LOH in oral SCCs using these arrays. DNA was extracted from tissue samples obtained from 10 patients with tongue SCCs who presented at the Hospital of Tokyo Dental College. We examined the presence of LOH in 3 of the 10 patients using these arrays. At the locus that had LOH, we examined the presence of LOH using microsatellite markers. LOH analysis using Affymetarix GeneChip Mapping 10K Array showed LOH in all patients at the 1q31.1. The LOH regions were detected and demarcated by the copy number 1 with the series of three SNP probes. LOH analysis of 1q31.1 using microsatellite markers (D1S1189, D1S2151, D1S2595) showed LOH in all 10 patients (100). Our data may suggest that a putative tumor suppressor gene is located at the 1q31.1 region. Inactivation of such a gene may play a role in tongue tumorigenesis.

Vertical fracture of mandibular condyle treated with intra-articular pumping therapy: a case report.

We report a patient with vertical fracture of the mandibular condyle visualized by computed tomography (CT). A 43-year-old woman visited our department the day after the injury occurred. At the initial examination, she experienced pain in the left temporomandibular joint (TMJ) when opening her mouth. Maximum mouth opening distance was 15 mm. Routine radiography showed normal findings, but CT revealed vertical fracture of the left mandibular condyle. Based on clinical findings, conservative therapy consisting of intra-articular pumping therapy and training for mouth opening was initiated. After 10 days, mouth opening distance increased to 36 mm, and pain in the left TMJ disappeared.

Genetic effects of X-ray and carbon ion irradiation in head and neck carcinoma cell lines.

The effects of X-ray and carbon ion irradiation on DNA and genes in head and neck carcinoma cells were examined. Four head and neck cancer cell lines (squamous cell carcinoma, salivary gland cancer, malignant melanoma, normal keratinocyte) were treated with 1, 4, and 7 GyE of carbon ion, or 1, 4, and 8 Gy of X-ray, respectively. DNA and RNA in the treated cells were extracted and purified. PCR-LOH (polymerase chain reaction-loss of heterozygosity) analysis with 6 microsatellite regions on chromosome 17 was performed to determine DNA structural damage, and then microarray analysis was performed to reveal changes in gene expression. PCR-LOH analysis detected high LOH in cells treated by radiation, indicating that most of the damage by X-ray occurred in the target region on one of the homologous chromosomes. However, carbon ion caused homo-deletion, which means deletion of the counterparts in both homologous chromosomes.

Intravascular papillary endothelial hyperplasia arising from the upper lip.

We report a rare case of intravascular papillary endothelial hyperplasia (IPEH) arising from the upper lip. Pathologically, it consisted of a few lobulated masses lined by an incomplete fibrous capsule of variable thickness which was separated from the surrounding tissue and which partially formed papillary structures bearing fibrous stalks and a single layer of endothelium. The capillary formation was poorly defined, and mitotic figures were frequently observed. Immunohistochemically, the endothelial cells were positive for factor VIII related antigen and vimentin, and many cells were positive for PCNA, not only in the solid proliferating area but also in the papillary proliferating area. This case represents IPEH with high proliferative activity.

In-house cDNA microarray analysis of gene expression profiles involved in SCC cell lines.

To analyze gene expression in oral cancer, we produced a specialized in-house cDNA microarray. The cDNA library was constructed from surgical specimens of oral squamous cell carcinoma (SCC) using an oligo-capping method. cDNA clones (n=4,800) were randomly selected and their 5'-end nucleotide sequences were determined. Overlapping clones were excluded, and 1,423 independent clones were selected and used for microarray production. Compared to the public nucleotide sequence database, 61% of our cDNA clones were full-length. By correlating expression patterns across SCC cell lines, we identified 53 genes (7 up-regulated and 46 down-regulated) that are differentially expressed in SCC cell lines compared to normal mucosa. Semi-quantitative RT-PCR analysis confirmed these findings and validity of our cDNA microarray. Using specimens from SCC patients, we investigated the expression status of the IL-1ra gene, which showed the down-regulated gene by microarray analysis. Gene expression clearly fell in the SCC specimens relative to their references, which indicated that our in-house cDNA microarray system rapidly identified and characterized candidate biomarkers for clinical use.

Over-expression of DNA methyltransferases and CDKN2A gene methylation status in squamous cell carcinoma of the oral cavity.

The present study was designed to investigate the potential relationship between CDKN2A (p16) gene hypermethylation, which has reported to be frequently observed in oral squamous cell carcinomas (OSCCs), and expression of human DNA methyltransferases (DNMTs: DNMT1, DNMT3A and DNMT3B). Twenty-five pairs of primary OSCCs and matched normal oral mucosa tissues were examined. The p16 gene was hypermethylated (48%) in the tumors showing significant down-regulation of both mRNA and protein expressions. A demethylation assay on 8 OSCC-derived cell lines was also performed by means of treatment with the demethylating agent, 5-aza-2'-deoxycytidine. Four of 5 cell lines showing down-regulation of the p16 gene, revealed re-activation of gene expression after the treatment. In contrast, frequent over-expression of DNMT mRNA expression, also found in the expression of the proteins, was detected: DNMT1 at 72% and DNMT3A at 56%, and DNMT3B at 64%, respectively. However, we could not identify any statistical significance between p16-hypermethylation status in individual tumors and the expression of any of the three DNMTs. These data suggest that hypermethylation of the p16 gene and up-regulation of DNMTs are involved in oral carcinogenesis, but they may be through different mechanisms.

High prevalence of decreased expression of KAI1 metastasis suppressor in human oral carcinogenesis.

PURPOSE: KAI1 was originally identified in prostate cancer as a metastasis suppressor gene. Recent studies have shown a frequent down-regulation of KAI1 expression in many tumor types, whereas mutation or hypermethylation of the gene is infrequent. The aim of the present study was to examine whether loss of KAI1 expression that might be caused by genetic or epigenetic alterations could contribute to oral carcinogenesis. EXPERIMENTAL DESIGN: We analyzed mutational and methylation status of the KAI1 gene and both the mRNA and protein level in a series of oral tumors [28 precancerous lesions, 101 primary oral squamous cell carcinomas (OSCCs), and 30 metastatic OSCCs] and OSCC-derived cell lines. We also examined p53 protein expression, which has been reported to be a candidate activator for the KAI1 gene. RESULTS: With the exception of three microsatellite instabilities in the KAI1 gene, we found no mutations in the coding sequence of the KAI1 gene, no loss of heterozygosity, and no hypermethylation of the KAI1 promoter region in all samples investigated. By immunohistochemistry, however, high frequencies of KAI1 down-regulation were evident not only in the metastatic OSCCs [29 of 30 (97%)] but also in the primary OSCCs [83 of 101 (82%)] and in the precancerous lesions [13 of 28 (46%)]. There was a significant relationship between down-regulation of KAI1 protein expression and primary tumors associated with lymph node metastases (P = 0.0115), whereas there was no statistical correlation between p53 status and KAI1 expression. Taken together, reverse transcription-PCR data were consistent with the protein expression status in 16 patients from whom mRNA was available. CONCLUSIONS: Our data suggest that whereas loss of KAI1 protein expression is associated with primary tumors with lymph node metastases, the down-regulation of KAI1 is an early event in the progression of human oral cancer. The down-regulation of KAI1 is not associated with either mutation, allelic loss, methylation of the promoter, or p53 regulation.