“Dredging Method” - A Conservative Approach for the Treatment of Ameloblastoma

“Dredging Method” - A Conservative Approach for the Treatment of Ameloblastoma

Daisuke Izumiyama, 

Tamaki Yamada, Yoichi Ohiro, Kanchu Tei

Oral and Maxillofacial Surgery, Department of Oral Pathobiological Science, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University

Ameloblastoma is an odontogenic tumor with variable clinical characteristics and histological patterns. Most cases are very extensive at the time of treatment because the tumor has painless and shows a slow and expansive growth. Ameloblastoma is a benign tumor, but the recurrence rate is extremely high if it is treated improperly. Therefore, the main treatment is still wide resection. The resection of the mandible is associated with many complications such as deformity, dysfunction, phychological distress and loss of jaw bone support even after reconstruction. We introduce a conservative procedure “Dredging Method”, which eradicates the tumor and restores the normal form and function of the jaw to overcome these disadvantages. “Dredging Method” consists of the four steps; Deflation, Enucleation, repeated Dredging, and Follow up. Deflation is the first step in which the portion of overlying bone and the tumor wall are removed. It is important to release intracystic pressure and make a single bony cavity. Enucleation is the second step in which the whole tumor is removed with the surrounding bone tissue. Dredging is the third step in which the scar tissue covered by bone surface and the surrounding bone tissue are removed. This step is performed repeatedly to accelerate the new bone formation and to eradicate the tumor cell nests in dredged out scar tissues with an interval of two to three months. Follow up is the last step. A continuous and regular follow up is important to identify the recurrence as a small lesion on X-ray before it sets large. Ameloblastoma is known to occur most commonly on the site of the lower molar. If the teeth are involved in Ameloblastoma, the teeth will almost be extracted because the tumor will recur at the surrounding the teeth. However, recently, in our department, we have tried to preserve both the jawbone and the teeth involved in Ameloblastoma by “modified-Dredging Method“. To preserve the teeth is very important for oral function. We are going to make a standard to preserve the teeth in the future.

(336 words)

Takahiro KANNO

Dr. Takahiro KANNO, DDS, PhD, FIBCSOMS

Department of Oral and Maxillofacial Surgery, Shimane University Faculty of Medicine (Director&Head: Prof. Joji Sekine, DDS, PhD, FIBCSOMS)

Brief C.V.

Dr. Takahiro Kanno, DDS, PhD, FIBCSOMS, graduated from School of Dentistry and Graduate School, Kyushu Dental College in 2001 (D.D.S.) and awarded Ph.D degree (Maxillofacial Surgery) from Graduate School of Kyushu Dental College (Head & Mentor: Prof. Tetsu Takahashi) in 2005. He worked at The Dept. of Oral and Maxillofacial Surgery of Kyushu Dental College (2001-2005) and at The Div. of Oral-Maxillofacial Surgery of Kagawa Prefectural Central Hospital (Director: Dr. Masaharu Mitsugi) (2005-2012). He studied abroad for clinical fellowships (AO fellow and IBRA fellow) at The Dept. of Oral and Maxillofacial Surgery, Ludwig-Maximilians-Universität Munich, Germany (2006) and at The Dept. of CranioMaxillofacial Surgery, University of Bern, Switzerland (2007). He is now employed by Shimane University Faculty of Medicine as a full time medical faculty (2012-present). He is Associate Professor, Deputy-Director of The Dept of Oral and Maxillofacial Surgery (Director & Head: Prof. Joji Sekine) and a part time faculty oral-maxillofacial surgeon of Kagawa Prefectural Central Hospital. He has more than 150 scientific papers published, among them 80 published in international journals and 250 abstracts. 　

Board Certification

Senior Consultant of Oral-Maxillofacial Surgery by JSOMS

Senior Consultant of Maxillofacial Implant Surgery by JAMI

General Clinical Oncologist by JBCT

Fellow of International Board Certified Specialist in Oral and Maxillofacial Surgery (FIBCSOMS) by IBCSOMS

Specialty: ・Surgical treatment of oral, head and neck cancer and reconstruction ・Maxillofacial trauma ・Orthognathic surgery　・Oral and maxillofacial implant surgery

A New Conception of Oral Potentially Malignant Disorders (PMDs) and Surgical Management of PMDs

A New Conception of Oral Potentially Malignant Disorders (PMDs) and Surgical Management of PMDs

JojiSekine, D.D.S., Ph.D., FIBCSOMS,

Takahiro Kanno, D.D.S., Ph.D., FIBCSOMS

Professor and Chairman,

Department of Oral and Maxillofacial Surgery, Shimane University Faculty of Medicine

89-1 Enya-cho, Izumo, Shimane 693-8501, Japan

Tel.: +81-853-20-2301

Fax: +81-853-20-2299

E-mail: georges@med.shimane-u.ac.jp

Oral squamous cell carcinoma (OSCC) comprises 92-95% of all oral cancers. OSCC sometimes show the features of oral epithelial dysplasia (OED), numerous criteria exist for the diagnosis of epithelial dysplasia, and there is not always a clear-cut distinction between what presents a mild dysplasia consisting only of focal dysplasia, which may represent carcinoma in situ (CIS). OED is usually confirmed to a single tissue compartment and may progress to cancer, but does not always do so. CIS or oral intraepithelial neoplasia (OIN) are lesions that have the morphologic characteristics of cancer, including atypical cells and dysplastic tissue organization, but are confirmed to one tissue component and do not penetrate the basement membrane. Numerous criteria exist for the diagnosis of OED, and there is not always a clear-cut distinction of what represents mild dysplasia— consisting of only focal atypia, moderate dysplasia, and severe dysplasia—which may present as OIN and CIS. Recently, such borderline lesions are called potentially malignant disorders (PMDs). This paper presents how we distinguish PMDs and other lesions as well as surgical management of PMDs.

The study included 114 patients (64 men, 50 women). All participants provided informed consent to participate, following approval of the study protocol (approval no. 996; March 26, 2012) by the ethics committee of Shimane University Hospital. In all patients, biopsy was done, which were formalin fixed, paraffin embedded.  Histopathological diagnoses was done by specialist of Pathology in our hospital. There were 67, 10, and 37 patients with OED, CIS, and OSCC, respectively. The expressions of Nucleus accumbens-associated protein 1 (NAC1), cytokeratine 13 and 17, human papilloma virus (HPV) 16, 18, and p16 were examined. Furthermore, c-mic, E-cadherin, vimentin and Ki-67 were also used for distinguishing PMDs.

       NAC1 labeling indices (Lis) cut-off values which discriminated between OED and CIS/OSCC were 50%. NAC1 was also available for distinguishing normal and OED with LIs cut-off value of 60%.OED and OIN was distinguished using Ki-67 and c-mic, on the other hands, OIN and OSCC was distinguished by the expression of E-cadherin and vimentin.

In conclusion, PMDs (borderline lesions between normal and malignancy) are very difficult to be diagnosed by routine HE staining. Our approach by various immunohistochemical staining would be feasible to distinguish PMDs from normal and OSCC. Regarding the management of PMDs, surgery should be indicated as some PMDs show features of malignancy. More detailed study would be needed for accurate diagnoses of PMDs.

Professor Joji George SEKINE

Joji George Sekine, D.D.S., Ph.D., FIBCSOMS

関根　淨治　教授

        Professor and Chairman, Department of Oral and Maxillofacial Surgery,

         Shimane University Faculty of Medicine,

         89-1 Enya-cho, Izumo 693-8501, Japan. 

         Tel: +81-853-20-2301, Fax: +81-853-20-2299,

         E-mail: georges@med.shimane-u.ac.jp

         http://www.med.shimane-u.ac.jp/oral/index.html

Education

1989 Graduated Fukuoka Dental College (D.D.S.)

1996 Awarded the degree of Ph.D. (Nagasaki University)

Research and professional experiences

1989-1990 Resident, Department of Anatomy, Fukuoka Dental

          College

1990-1991 Resident, Department of Oral and

          Maxillofacial Surgery, Nagasaki University Dental   

          Hospitals

1991-1992 Resident. Department of Anesthesiology and Intensive

          Care Unit, Nagasaki University Medical Hospital

1992-1999 Assistant professor, Nagasaki University Dental Hospital,                                                                

          working  under  Professor Tsugio Inokuchi on oral  

          cancer resection and reconstructive  surgery 

          using bone, flap and dental implant.

1999-2007 May

           Lecturer, Department of Oral and Maxillofacial Surgery, 

           Nagasaki University Medical and Dental Hospital

2006 Sep.- 2007 May 

　　　　　 Visiting professor, Department of Oral & Maxillofacial Surgery,

           Umeå University

2007 Jun.-  Professor and Chairman, Department of Oral and Maxillofacial Surgery,

           Shimane University Faculty of Medicine

           Head, Maxillofacial Implant Center, Shimane University Medical Hospital

2013.Apr.-  Visiting Professor, Health Science University of Mongolia

Specialty

・ Senior consultant and accredited maxillofacial surgeon, Japanese Society of 

 Oral and Maxillofacial Surgeons

・ Senior consultant, Japanese Academy of Maxillofacial Implants

・ Certified cytopathologist, Japanese Society of Clinical Cytology

・ Clinical instructor certified by Minister of Health, Labor and Welfare

・ Clinical oncologist, Certified by Japanese Board of Cancer Therapy (JBCT)

・ Fellow of International College of Surgeons (FICS)

・ Fellow of the International Board for the Certification of Specialists

 in Oral and Maxillofacial Surgery (FIBCSOMS)

・ Accredited oral oncologist, Certified by Japanese Society of Oral Tumors

Awards

・April 2007 International College of Surgeons Research Scholarship Grant

・June 2007 International College of Surgeons Young Investigator’s Award,

    ‘Oral rehabilitation by means of Osseointegrated Implants in  

    Oral Cancer Patients’, The 52^nd Annual Congress of the Japan 

    Section

“TENT POLE” GRAFTING For Complicated Alveolar Defects

 “TENT POLE” GRAFTINGFor Complicated Alveolar Defects

Professor Michael Yuanchien CHEN

“TENT POLE” concept for reconstruction of severely resorbed mandible as an adjunct procedure of complicated implant restoration was first advocated by Prof. Robert E. Marx who published a series of 64 consecutive successful cases through submental approach in the year 2002. However, in my hand, the “Tent Pole” grafting concept could also be extrapolated in atrophic upper & lower jaws with significantly vertical dimensional loss through intraoral approach either by para-crestal or vestibule incisions. Of all the biomaterials serving the purpose as “Tent Pole”, I’d like to introduce autogenous iliac “J-Bone Block” which is basically an onlay bone graft harvested from anterio-medial aspect of ilium. It allowed contour adjustment only by simple hand instruments such as rongeur or bone cutter, to be secured properly and intimately at recipient site by one mini-screw on each bone block so that transverse & vertical alveolar ridge augmentation could be achieved simultaneously. According to the differences of Pre-Op & 6 months Post-Op CBCT images calculated by computer software, “Mimics” , the average early volume shrinkage of the transplanted iliac J-Bone Blocks is about 17.3% with usually more than enough ridge volume left for placing regular diameter dental implants at ideal location and axial alignment. Subsequent overall survival rates of all these implant supported restorations are high above 90% in this author’s case series.

Computer Assisted & Ultrasonic Facial Skeletal Surgery ~ Efficiency, Precision and Safety ~

Computer Assisted & Ultrasonic

Facial Skeletal Surgery

~ Efficiency, Precision and Safety ~

Michael Yuanchien CHEN

Computer Assisted Surgery (CAS) can be categorized into 3 subgroups, robotic surgery, navigation systems and CAD/CAM technology. However, robotics seemed to be more practical and limited to soft tissue dissection while navigation procedures are generally considered time consuming during preoperative setting.

So, the outcomes of utilizing computer-aid virtual planning(CAD) and additive manufactured cutting / positioning guides(CAM) as well as powerful ultrasonic apparatus (BoneScalpel ^TM by Misonix Inc, Farmingdale, NY, USA & BONEMED Surgery Unit ^TM, VIA-TECH Biomedical. Co. Ltd, Taiwan) with tissue selective cutting characteristics in a series of more than 100 patients underwent 2-jaw orthognathic surgery in the OMS department of China Medical University Hospital, Taichung City, Taiwan from Jul. 2014 ~ Jul. 2017 will be presented. Both efficiency and preciseness are significantly improved by applying CAD/CAM technology in our case series especially for asymmetric cases when complicated pitch, roll, yaw are inevitable in which traditional 2D analysis is certainly insufficient and not reliable. The same CAD/CAM concepts are also applicable to cosmetic facial bone contouring and selected cases of benign jaw bone tumor resection with immediate reconstruction through trans-oral approach.

Professor Michael Yuanchien CHEN

Professor Michael Yuanchien CHEN

陳　遠謙　理事長

Current positions:

Chairman,

Dental Department & Division of Oral Maxillofacial Surgery,

China Medical University Hospital, Taichung City, TAIWAN.

Associate Professor,
College of Dentistry, China Medical University, Taichung City, TAIWAN.

President,

Taiwanese Association of Oral & Maxillofacial Surgeons(TAOMS).

Executive Council(Member-At-Large, 2016~2018),

Asian Association of Oral & Maxillofacial Surgeons.

Experiences:

Congress chairman,

2008  Annual Conference of TAOMS.

2016  Annual Conference of TAOMS.

2017  ACE Forum on OgS at China Medical University, Taichung, Taiwan.

International Committee Chair of TAOMS (2011~2017)

Education:

1980~1986 D.D.S.  School of Dentistry, Kaohsiung Medical University, Taiwan.

1993  Advanced Implant Course, University of Alabama at Birmingham, USA.

1998  Autogenous Bone Grafting Course, University of Miami, USA.

2000~2002 M.S. Institute of Medical Science, China Medical University, Taiwan.

2001  Orthognathic Surgery Course, National Seoul University, Korea.